فهرست مطالب

  • سال شانزدهم شماره 5 (آذر و دی 1398)
  • تاریخ انتشار: 1399/03/03
  • تعداد عناوین: 8
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  • رضا کیانتاژ، علی رمضانی*، ناهید امراللهی صفحات 1-13
    زمینه و هدف

    امروزه می توان از فرهنگ ایمنی در سازمانهای صنایع مختلف، به عنوان یک مزیت رقابتی بلند مدت نام برد که بهبود آن منجر به جلوگیری از وقوع حوادث پرهزینه برای انواع سازمانها در کشورهای مختلف می شود. بعد از حادثه ی نیروگاه اتمی چرنوبیل و گزارش کارشناسان ایمنی آژانس بین المللی انرژی اتمی در مورد کاستی های فرهنگ ایمنی در آن نیروگاه، روش های مختلفی برای تعریف و سنجش مفهوم فرهنگ ایمنی در سازمانها و شیوه های تاثیرگذاری و ارتقاء آن مفهوم ارایه شده است. از طرف دیگر مفاهیم مدیریت دانش و یادگیری سازمانی نیز جزو موضوعاتی هستند که ارتباط تنگاتنگی با مفهوم فرهنگ سازمانی دارند و تحقیقات بسیاری جهت تحلیل اثرات آنها بر مولفه های گوناگون سازمانی در صنایع مختلف انجام شده است. در این راستا این مطالعه با هدف بررسی تاثیر استقرار فرایندهای مدیریت دانش در ارتقاء جایگاه مفهوم فرهنگ ایمنی در سازمان به اجرا درامده است.

    روش بررسی

    در این تحقیق ابتدا مدل نظری مناسب در مورد ارتباط بین پنج مشخصه ی فرایندهای مدیریت دانش)اخذ دانش، تسهیم دانش، خلق دانش، کدگذاری دانش و نگهداشت دانش) و فرهنگ ایمنی در سازمان ارایه شد و سپس به صورت تجربی داده های جمع آوری شده از نمونه آماری 98 نفره از کارکنان ایرانی درگیر در عملیات اصلی راکتورهای اتمی ایران با روش حداقل مربعات جزیی (PLS) از روش های جدید تکنیک مدل سازی معادلات ساختاری (SEM) مورد تجزیه و تحلیل همبستگی قرار گرفت. نرم افزار مورد استفاده در این تحلیل SmartPLS 3 بود و از پرسشنامه کیانتو (Kianto, 2008) برای سنجش فرایندهای مدیریت دانش و پرسشنامه آژانس بین المللی انرژی اتمی (SCPQ-LH) در سال 2017 برای سنجش سطح فرهنگ ایمنی در سازمان استفاده شد. در ادامه با توجه به عنوان شغلی کارکنان و ارتباط آن با موضوع ایمنی، مدل ارایه شده برای دو گروه 1- کارکنان بخش های مرتبط با ایمنی مانند بخش های حفاظت در برابر اشعه و HSE و... و 2- دیگر کارکنان درگیر در عملیات اصلی راکتور هسته ای مانند کارکنان بخش های تولید، مهندسی یا کنترل کیفی نیز مورد بررسی و تحقیق قرار گرفت و شدت نتایج همبستگی بدست آمده با توجه به ارتباط عنوان شغلی کارکنان به موضوع ایمنی مورد توجه قرار گرفت.

    یافته ها

    یافته های بدست آمده در این تحقیق نشان داد که مدیریت دانش قادر به تبیین 57 درصد از تغییرات متغیر فرهنگ ایمنی برای کارکنان عملیاتی این تاسیسات اتمی می باشد. به ویژه که نتایج تحقیق از تشدید این همبستگی به 62 درصد در میان پرسنل واحدهای مرتبط با ایمنی که فرایندهای مدیریت دانش را بیشتر برای دانش ایمنی بکار گرفته بودند در مقابل دیگر پرسنل فعال در عملیات اصلی تاسیسات (به میزان 53 درصد) حکایت داشت.

    نتیجه گیری

    نتایج حاصل از این پژوهش نشانگر این موضوع است که استقرار فرایندهای مدیریت دانش، بویژه دانش مرتبط با ایمنی)احتمالا در اثر تسهیل و بهبود مبحث یادگیری سازمانی) تاثیر مستقیمی در ارتقاء فرهنگ ایمنی در سازمان دارد و می توان از سیستم مدیریت دانش به عنوان عاملی در جهت ارتقاء فرهنگ ایمنی در سازمان در بلند مدت بهره جست. در این راستا طرح ریزی سیستم مدیریت دانش سازمان به صورت هدفمند و تاکید آن بر مدیریت دانش ایمنی می تواند به عنوان عاملی در جهت تشدید و تسریع ارتقاء فرهنگ ایمنی در سازمان بکارگرفته شود. از دیگر نتایج بدست آمده در این تحقیق ارتباط تنگاتنگ سیستم مدیریت دانش سازمان با موضوع یادگیری سازمانی است. که بر اساس این نتیجه فرایندهای مدیریت دانش تقدمی بر مفهوم مدیریت دانش در سازمان ندارند و نمی توان فرایندهای مدیریت دانش را به عنوان عامل سازنده ی سازه ی مدیریت دانش در سازمان در نظر گرفت بلکه مفهوم مدیریت دانش در سازمان وجود مستقلی است که تاثیر مستقیمی بر یادگیری سازمانی و مفهوم فرهنگ سازمانی دارد و حتی می توان این سیستم را از طریق اثرات تاثیر آن بر موضوع یادگیری سازمانی تعریف کرد و سنجید.

    کلیدواژگان: فرهنگ ایمنی، مدیریت دانش، فرهنگ سازمانی
  • رضا رمضانیان*، سید سعید حسن الحسینی صفحات 14-29
    زمینه و هدف

    رتبه بندی یک نوع معیار صلاحیت گذاری بر اساس استانداردهای تعریف شده است و  برای تضمین کیفیت و کمیت پیمانکاران در ارایه ی خدمات و دفاع از حقوق ذینفعان و استفاده کنندگان می باشد. رویکرد ترکیبی فرآیند تحلیل سلسله مراتبی فازی و تاکسونومی به عنوان روش های تصمیم گیری چندمعیاره، به تصمیم گیرندگان کمک می کند تا مشکلات را سازماندهی و تحلیل، و گزینه ها را اولویت بندی کنند. در این تحقیق به شناسایی شاخص ها، انتخاب سنجه ها و وزن دهی شاخص ها و همچنین ارزیابی عملکرد نظام مدیریت HSE پرداخته شده است. در نهایت، 5 سازمان فعال در صنعت ساخت شناور با روش تاکسونومی رتبه بندی شده اند.

    روش بررسی

    مطالعه حاضر از نوع توصیفی- تحلیلی و کاربردی است. جامعه آماری این پژوهش دانش آموختگان رشته های مرتبط با مقوله ایمنی، بهداشت و محیط زیست با سابقه کار در زمینه ارزیابی عملکرد می باشند. تعداد نمونه 8 نفر بوده که با توجه به نوع نمونه گیری یعنی غیراحتمالی، هدفمند و در دسترس، این تعداد با هدف مطالعه سازگار می باشد. استانداردهای ISO 14001:2015 و ISO 45001:2018 و نیز دروس دانشگاهی مهندسی ایمنی صنعتی، مهندسی بهداشت حرفه ای و مدیریت/مهندسی محیط زیست و همچنین استفاده از نظرات خبرگان مبنای شناسایی شاخص های مدیریتی و عملیاتی این نظام مدیریت می باشند. جهت کمی نمودن هر شاخص ، سنجه هایی تعیین می گردد. خبرگان پس از انتخاب سنجه ها، به آن ها وزن داده که با استفاده از رویکرد فرآیند تحلیل سلسله مراتبی فازی به روش واکاوی توسعه ای و بکارگیری مقایسات زوجی، وزن شاخص ها و سنجه ها تعیین گردید. در نهایت، با استفاده از سنجه های منتخب به ارزیابی عملکرد این نظام مدیریت در 5 سازمان فعال در صنعت ساخت شناور با روش تاکسونومی پرداخته شد.

    یافته ها

    با بررسی ادبیات موضوع و دریافت نظرات خبرگان، 10 معیار کلی و 54 شاخص شناسایی گردید بطوری که تعداد شاخص ها و زیرشاخص های مدیریتی به ترتیب 7 و 28 مورد و تعداد شاخص ها و زیرشاخص های عملیاتی به ترتیب 3 و 26 مورد می باشد، با این حال با توجه به مقایسات زوجی انجام شده، مجموع وزن شاخص های مدیریتی معادل 5/40 درصد و مجموع وزن شاخص های عملیاتی معادل 5/59 درصد می باشد. با وجود تعداد بیشتر شاخص های مدیریتی، وزن و اهمیت شاخص های عملیاتی در ارزیابی عملکرد  HSEبیشتر است. 3 معیار عملیاتی بیشترین اوزان را به خود اختصاص داده و پس از آن معیارهای مدیریتی قرار می گیرند. همچنین از بین 54 شاخص شناسایی شده، 6 شاخص اول که دارای بیشترین وزن هستند همگی از نوع شاخص های عملیاتی و 6 شاخص آخر که دارای کمترین وزن می باشند از نوع شاخص های مدیریتی هستند. نتایج رویکرد پیشنهادی نشان داد سازمان اول در اولویت اول قرار گرفته است. رتبه بندی سازمان ها با احتساب اوزان شاخص ها و بدون احتساب آن ها محاسبه شد که نتیجه حکایت از تاثیر اوزان شاخص ها در رتبه بندی سازمان ها دارد. لحاظ این مهم در ارزیابی عملکرد سازمان ها بخصوص در حوزه نظام مدیریت ایمنی، بهداشت و محیط زیست پیشنهاد می گردد.

    نتیجه گیری

    نتایج تحقیق انجام شده نشان داد می توان روش ترکیبی پیشنهادی شامل فرآیند تحلیل سلسله مراتبی فازی و تاکسونومی را با موفقیت به منظور ارزیابی عملکرد نظام مدیریت HSE به کار گرفت. به نظر می رسد ارزیابی عملکرد با استفاده از روش های تصمیم گیری به همراه مشارکت نیروهای انسانی می تواند منتج به اثربخشی بیشتر این نظام مدیریت شود.

    کلیدواژگان: ارزیابی عملکرد، نظام مدیریت ایمنی، بهداشت و محیط زیست، فرآیند تحلیل سلسله مراتبی فازی، تاکسونومی
  • حمیده نیک نظر، امیر هوشنگ مهرپرور، مصطفی بهجتی، علی دهقانی، محمدجواد زارع* صفحات 30-39
    زمینه و هدف

    در حال حاضر در نتیجه پژوهش روی حیوانات آزمایشگاهی، اطلاعات فروانی از تاثیر عوامل مختلف محیطی در وقوع ناهنجاری های مادر زادی به دست آمده است، اما هنوز اطلاعات جامعی در خصوص علل وقوع ناهنجاری های مادرزادی قلبی(CHD) در جمعیت های انسانی وجود ندارد.. محققان بیان کرده اند مشاغلی مانند داروسازی ، مهندسی شیمی، رنگرزی که افراد در معرض حلال ها قرار می گیرند، خطر ابتلای نوزاد به نقایص چشمی، قلبی و روده ای و شکاف لب و کام را افزایش می دهد. در مطالعه اسنیدجر میان تماس شغلی مادران وCHD  فرزندان ارتباطی مشاهده نشد در حالیکه تماس پدران با فتالات باعث افزایش CHD در نوزادان گردید. با توجه به مطالب ذکر شده شناخت عوامل محیطی و شغلی موثر در بروز ناهنجاری های مادرزادی قلب از جمله مواجهات شغلی پدران می تواند به شناخت عوامل غیر ژنتیکی موثر در بروز ناهنجاری های مادرزادی قلب کمک کند بنابرای این مطالعه با هدف بررسی مواجهه شغلی پدران با حلال ها و بروز ناهنجاری مادرزادی قلب نوزادان انجام شد.

    روش بررسی

    مطالعه حاضر به صورت مورد- شاهدی بر روی600 کودک انجام شد. 200 کودک مبتلا به ناهنجاری های مادرزادی قلب تشخیص داده شده (گروه مورد) و 400 کودک سالم (گروه شاهد) بودند. ابزار گردآوری پرسشنامه ی محقق ساخته بود که از طریق مصاحبه تلفنی توسط پژوهشگر تکمیل شد. سوالات پرسشنامه شامل اطلاعات دموگرافیک، شغل پدر، سبک زندگی و عوامل محیطی بود. پس از تکمیل پرسشنامه ها بررسی مواجهه شغلی پدر با استفاده از روش ماتریکس ارزیابی شغل انجام گرفت. بدین منظور ماتریس ارزیابی مواجهه شغلی با حلال ها در نرم افزار اکسل تهیه گردید. امتیاز دهی به مواجهه هر شغل با حلال براساس نظرات 10 نفر از کارشناسان بهداشت حرفه ای با تجربه و آشنا به مشاغل مختلف انجام شد. جهت تحلیل داده ها از نرم افزار SPSS16 و شاخص های توصیفی و پراکندگی نظیر فراوانی و درصد استفاده شد همچنین جهت ارزیابی تماس شغلی از نرم افزار STATA14 و جهت برآورد نسبت شانس و نسبت شانس تطبیق یافته از آزمون های رگرسیون لجستیک استفاده شد.

    یافته ها

    شایع ترین ناهنجاری های مشاهده شده در این مطالعه نقص دیواره بین بطنی (63n=) %5/31 و باز بودن مجرای شریانی (48n=) 24% بود. نتایج مطالعه نشان داد که مادران گروه مورد در مقایسه با مادران گروه شاهد از سطح تحصیلات پایین تری برخوردار بودند (001/0p-value <). در این مطالعه نسبت جنسیتی دختر به پسر 1:06/1بود. نتایج مطالعه نشان داد که تماس شغلی پدران با حلال ها در نمونه مورد (66%) نسبت به نمونه شاهد (55%) بیشتر بوده است این رابطه از لحاظ آماری معنی دار می باشد (21/2-06/1CI= 95% ، 53/1OR=). بعد از حذف اثر عوامل مداخله گر ارتباط معناداری بین مواجهه پدر با حلال ها و ناهنجاری قلبی در نوزادان مشاهده نشد (84/0-6/1 CI= 95% ، 28/1 AOR=).

    نتیجه گیری

    از محدودیت های مطالعه تعداد نسبتا کم نمونه و محدود کردن مطالعه به بازه زمانی خاص و همچنین استفاده از ماتریکس ارزیابی شغل به تنهایی و عدم اندازه گیری بیو مارکر های حلال ها در بافت و مایعات بدن والدین و جنین بود. با وجود محدودیت های مطالعه یافته های مطالعه نشان داد که یکی از عوامل محیطی تاثیرگذار بر سلامت جنین مواجهات شغلی پدران از جمله مواجهه با حلال ها می باشد. بنابراین نظارت بر بکارگیری استاندارهای بهداشتی در محیط کار و آموزش زوج های جوان در خصوص عوامل غیرژنتیکی موثر در بروز ناهنجاری ها مادرزادی، می تواند در سلامت نسل آینده موثر می باشد.

    کلیدواژگان: کلیدواژه ها: ناهنجاری های مادرزادی قلب، حلال ها، مواجهه شغلی پدران، ماتریکس ارزیابی شغل
  • محمدامین رشیدی، روح الله حاجی زاده، محمدحسین بهشتی، عظیم اکبری، عبدالحسین پورنجف، علی خوانین*، مسعود پورنجف، فرشته نیکوند، یوسف فقیه نیا ترشیزی صفحات 40-51
    زمینه و هدف

    شرایط جوی نامناسب از جمله عوامل زیان آوری هستند که اکثر شاغلین در محیط های کاری مخصوصا محیط هایی که هم فرایند کار و هم شرایط جوی منطقه نامناسب است، با آن سروکار دارند. بطور کلی کارگران شاغل در قنادی ها مخصوصا در فصل تابستان با استرس گرمایی بالایی مواجهه دارند. بنظر می رسد مواجهه با گرمای بیش از حد علاوه بر اینکه با اختلال در سیستم فیزیولوژی و سلامتی افراد سبب ایجاد بیماری ها و عوارض متعددی می گردد، راندمان و بازده کاری را نیز تحت تاثیر قرار می دهد. این مطالعه با هدف تعیین میزان استرس گرمایی در شاغلین کارگاه های قنادی در شهرستان ایلام انجام گرفت.  

    روش بررسی

    این مطالعه به صورت توصیفی- تحلیلی در تابستان 1396 بر روی 104 نفر از کارگران شاغل در 35 کارگاه قنادی انجام گرفت. تعداد نمونه ی پژوهش بر اساس روش سرشماری انتخاب گردید. اندازه گیری متغیرهای مورد مطالعه در گرم ترین ساعات روزکاری (ساعات 10 الی 14) و برای هر کارگر تنها یک بار و آن هم در بدترین ایستگاه کاری (نزدیک ترین ایستگاه به منبع گرما) انجام گرفت. ارزیابی استرس گرمایی با استفاده از شاخص WBGT (بر اساس استاندارد ISO7243) و شاخص DI صورت گرفت. همزمان با اینکه پارامترهای محیطی مورد سنجش قرار گرفتند، دمای دهانی کارگران توسط یک دماسنج پزشکی دیجیتال اندازه گیری گردید. در نهایت تجزیه و تحلیل داده های جمع آوری شده با استفاده از نرم افزار SPSS 22 و آزمون های آماری کولموگروف- اسمیرنوف، من ویت نی، کروسکال والیس، آنالیز واریانس یک طرفه و همبستگی پیرسون انجام گرفت.

    یافته ها

    یافته های این مطالعه نشان داد که میانگین شاخص WBGT بر حسب شغل در مشاغل فر، پهن کن، مخلوط کن و نظافت و بسته بندی به ترتیب 96/3 ± 66/33، 05/3 ± 58/29، 61/3 ± 73/31، 44/2 ± 87/29 و همچنین بر حسب فر (محصول) در فر گردان (شیرینی تر و خشک)، فر طبقه ای (کیک و نان فنتزی) و فر کوره ای (باقلوا و کعک) به ترتیب 86/3 ± 94/30، 89/3 ± 14/34 و 91/2 ± 2/32 می باشد که این نتایج نشان می دهد میزان استرس گرمایی در بخش کار با دستگاه فر و محصول کیک و نان فانتزی (فر طبقه ای) بیشتر از بقیه بخش ها بوده است. آزمون همبستگی پیرسون نشان داد که هیچگونه همبستگی معنی داری بین دمای دهانی با شاخص ها و متغیرهای مورد مطالعه وجود ندارد (05/0<p). نتایج آزمون من ویت نی مشخص کرد که بین متغیر جنسیت با دمای دهانی تفاوت معنی دار آماری وجود داشت (05/0>p) به طوریکه میانگین این متغیر در زنان با میانگین 27/0 ± 7/36 بیشتر از مردان با میانگین 84/0 ± 42/36 بود. نتایج مطالعه حاضر نشان داد که 6/85 % از افراد مورد مطالعه از لحاظ شاخص احساس ناراحتی (DI) در حیطه شدید قرار گرفتند.

    نتیجه گیری

    طبق نتایج، تقریبا کلیه ی شاغلین کارگاه های قنادی در معرض استرس گرمایی می باشند اما کارگران شاغل در زیرگروه های شغلی فر و مخلوط کن، فر طبقه ای (محصولات کیک و نان فانتزی) و فر کوره ای (محصولات باقلوا و کعک) و همچنین جنس مونث در معرض استرس گرمایی بالاتری قرار دارند و بنابراین در زمان اتخاذ اقدامات کنترلی اولویت با چنین افرادی می باشد. بنابراین اعمال راهکارهای کنترلی از قبیل استفاد از عایق های حرارتی، برقراری سیستم تهویه مطبوع و غیره ضروری و الزامی می باشد.

    کلیدواژگان: استرس گرمایی، شاخص WBGT، شاخص DI، شاغلین قنادی
  • ابوالفضل قهرمانی*، الیاس تقی زاده، ایرج محبی صفحات 52-61
    زمینه و هدف

    قوانین و مقررات ایمنی و بهداشت شغلی[1](OHS) کشور ما با هدف تامین شرایط بهداشتی و ایمنی در محیطهای کاری تدوین شده اند. اجرای الزامات مقررات OHS نقش زیادی در ارتقاء وضعیت OHS در سازمان ها دارند و رویکردهای مختلف مدیریت ایمنی بر انطباق با الزامات مقررات OHS تاکید دارند. بررسی ها نشان می دهد که مقررات OHS در محیط های کاری مختلف بویژه در کشورهای در حال توسعه به طور کامل اجرا نمی شوند. در آیین نامه کمیته حفاظت فنی و بهداشت کار [2](CTPHW) بر تشکیل جلسات کمیته تاکید شده که از آن طریق باید مسایل مربوط به OHS در محیطهای کاری مورد بررسی قرار گیرد تا تصمیماتی برای ارتقاء وضعیت OHS در سازمان ها انجام شود. بررسی ها نشان داد که تابحال هیچ مطالعه پژوهشی در زمینه نحوه اجرای این آیین نامه در سازمان ها و بررسی محتوای مستندات مربوطه در مجلات علمی گزارش نشده است. لذا این مطالعه با هدف بررسی محتوای صورتجلسات CTPHW شرکت های تولیدی انجام شد.

    روش بررسی

    برای انجام این مطالعه کیفی، تعداد 740 صورتجلسه مربوط به سالهای 94-90 جمع آوری شد. شرکت تولیدی در یکی از شهرستان های شمالغرب کشور قرار داشتند. در این مطالعه متن مستندات کاغذی و الکترونیکی صورتجلسات CTPHW با استفاده از از روش تحلیل محتوا[3] و براساس سوالات پژوهشی به موضوعات و دسته های موردی سازماندهی شدند. هر کدام از صورتجلسات برای چندین بار بررسی شدند تا تعداد بندها، کلمات مهم و طرح های کنترلی مصوب مشخص شوند. هر کدام از صورتجلسات به صورت کلمه به کلمه کدگذاری شدند و طرح های کنترلی مصوب توسط اعضای CTPHW از نظر نوع روش مورد استفاده برای کنترل خطرات، عادی (روتین) یا غیر عادی (غیر روتین) بودن و همچنین از نظر موضوعی ایمنی، بهداشتی و ارگونومی مورد بررسی قرار گرفتند.

    یافته ها

    بررسی محتوای صورتجلسات نشان داد که بیشترین تعداد صورتجلسات (241 مورد) مربوط به سال 94 و کمترین تعداد (34 مورد) مربوط به سال 90 بود. از نظر موضوعی بیشترین تعداد بند ها و کلمات مربوط به ایمنی  و کمترین تعداد مربوط به ارگونومی بودند. تعداد کل طرح های کنترلی در این مطالعه 2553 مورد بود که بیشترین طرح های مورد بحث مربوط به مهندسی (958 مورد) و کمترین آنها مربوط به اعمال کاری (145 مورد) بود.

    نتیجه گیری

    یافته های این مطالعه نشان داد که الزامات آیین نامه CTPHW بدرستی در شرکت های تولیدی مورد مطالعه اجرا نشده است. این مطالعه بر پیگیری های بیشتر سازمانهای قانونی ذیربط برای اجرای هر چه بهتر الزامات این آیین نامه CTPHW در شرکت های تولیدی تاکید دارد. آموزش و تشویق شرکت های تولیدی از طرف سازمان های قانونی ذیربط می تواند از طریق فرهنگ سازی درست ایمنی، اجرای الزامات آیین نامه CTPHW و ارتقاء وضعیت OHS را در آنها در پی داشته باشد.

    کلیدواژگان: مطالعه کیفی، بررسی مستندات، تحلیل محتوی، ایمنی، ضمانت اجرایی
  • جلیل درخشان، مجید معتمد زاده، عرفان طاهرپور، رستم گلمحمدی، محمد بابامیری*، مریم فرهادیان صفحات 62-74
    زمینه و هدف

    صدا یکی از موثرترین عوامل برون زاد تاثیر گذار بر مکانیزم های پردازشی مغز انسان است که نقش عمده ای در بروز خطاهای انسانی و حوادث شغلی دارند. صدای کم فرکانس از مهم ترین منابع مولد صدا در محیط است و  حتی در ترازهای پایین آزاردهنده بوده و عملکرد شناختی افراد را تحت تاثیر قرار می دهد. برخی از تفاوت های فردی مانند دست برتری، برون گرایی، روان رنجور خویی و حساسیت به صدا می توانند تاثیر صدا بر عملکردهای شناختی را کاهش یا افزایش دهند. هدف این تحقیق بررسی اثر دست برتری بر عملکردهای شناختی در حضور صدای با فرکانس پایین می باشد.

    روش بررسی

    پژوهش حاضر از نوع مداخله ای می باشد. جامعه پژوهش دانشجویان دانشگاه علوم پزشکی همدان بودند که از میان آن ها تعداد 120 نفر به روش نمونه گیری هدفمند (40 نفر راست دست، 40 نفر دوسو توان و40 نفر چپ دست) انتخاب شدند. کلیه آزمایش ها در دانشکده بهداشت دانشگاه علوم پزشکی همدان و در یک اتاق با شرایط آکوستیکی و فیزیکی کنترل شده در اسفندماه سال 1396 صورت گرفت. برای تعیین دست برتری از پرسشنامه دست برتری چاپمن استفاده شد. با شبیه سازی محیط واقعی هر یک از افراد موردمطالعه درشدت صوت متداول در صنعت (45 و 65 دسی بل) به مدت 40 دقیقه در معرض مواجهه قرار گرفتند. شرایط محیطی در شرایط آسایش حرارتی و معادل با دمای تر گوی سان 18 درجه سلسیوس و رطوبت نسبی 50 درصد بدون وجود جریان هوای مزاحم ثابت نگاه داشته شد. همچنین با استفاده از لامپ های فلورسنت و هالوژن روشنایی 500 لوکس با سطح درخشندگی مطلوب سطوح تامین و در طول انجام تمامی آزمایش ها ثابت نگاه داشته شد. در این مطالعه از صدای ضبط شده سیستم تهویه صنعتی در محیط کار استفاده شد که با استفاده از نرم افزارCool edit Program  در باند فرکانسی مدنظر ویرایش گردید و در حین مواجهه با استفاده از آزمون عملکرد پیوسته دیداری-شنیداری ((IVA PLUS CPT عملکردهای شناختی(زمان واکنش، توجه، تعادل، تمرکز و سرعت پردازش) افراد موردبررسی قرار گرفت. داده ها با استفاده از نرم افزار SPSSv:20 و آزمون کروسکال والیس و تحلیل واریانس موردبررسی قرار گرفتند.

    یافته ها

    میانگین سنی افراد 94/23 با انحراف معیار 25/3 بود. توزیع افراد مورد آزمایش ازنظر جنس، فقط مردان بودند و 85 درصد از آن ها را مجردان و بقیه را متاهلین تشکیل می دادند. بیشتر شرکت کنندگان این مطالعه از رشته های علوم بهداشتی و مقطع تحصیلی 80 درصد آن ها نیز کارشناسی بود.   نتایج نشان داد با افزایش تراز صوت از 45 به 65 دسی بل صدا با فرکانس پایین عملکردهای شناختی افراد بهبود پیدا می کند و همجنین بین مولفه های عملکردهای شناختی و دست برتری تفاوت معناداری وجود دارد(05/0p<)، بطوریکه افراد راست دست مولفه های شناختی شنیداری بهتر، و افراد چپ دست مولفه های شناختی دیداری بهتری نسبت به هم داشتند و عملکرد دو سو توان نسبت به دو گروه دیگر در سطح بالاتری قرار دارد (0/05>p).

    نتیجه گیری

    نتایج این مطالعه نشان می دهد که مواجهه با صدا فرکانس پایین در مولفه های عملکردهای شناختی شرکت کنندگان تاثیرگذار بود و همچنین  بین افزایش تراز صوت و مولفه های عملکردهای شناختی با دست برتری رابطه معناداری وجود دارد. حین مواجهه با صدا افراد دو سو توان مولفه های عملکردهای شناختی بالاتری داشتند. بر این اساس در پست های کاری و وظایف شغلی حساس که نیازمند استفاده از عملکردهای شناختی هستند اثر دست برتری افراد باید مد نظر قرار گیرد.

    کلیدواژگان: صدای فرکانس کم، دست برتری، عملکرد شناختی
  • سمیرا کاظمی، علی صفری واریانی، حدیث خوشنواز، احمد نیک پی* صفحات 75-87
    زمینه و هدف

    کیفیت هوا در محیط های داخلی  یکی از موضوعات مهم در حوزه سلامت می باشد که در چند سال اخیر و با تغییر در الگو های زندگی مورد توجه قرار گرفته است. تولوین یکی از ترکیبات آلی با کاربرد گسترده صنعتی می باشد. این ترکیب ها به دلیل فشار بخار بالایی که دارند از پتانسیل انتشار و ایجاد مواجهه تنفسی در فرآیندهای ساخت و حتی در هنگام استفاده از محصولات که در ساخت آنها استفاده شده اند برخوردار هستند. با توجه به اثرات بهداشتی ترکیبات آلی فرار، کنترل آنها پیش از تخلیه به محیط زیست و همچنین ارایه روش هایی برای کنترل آنها در محیط های داخلی ضروری به نظر می رسد. فرآیند اکسیداسیون فوتوکاتالیتیکی ترکیبات آلی فرار یکی از روش های موثر و همسو با محیط زیست در زمینه حذف ترکیبات آلی فرار محسوب می شود. مهم ترین محدودیت این روش، وابستگی حذف آلاینده به شیمی سطح و زمان ماند آلاینده بر سطح بستر می باشد. در این مطالعه به منظور بهبود افزایش زمان ماند و بهبود کارایی حذف، از مخلوطی از دی اکسید تیتانیوم و کربن فعال در ساخت بستر جذبی- فوتوکاتالیتیکی استفاده شد. این مطالعه با هدف بررسی کارایی حذف بخار تولوین در بستر جذبی-فوتوکاتالیتیکی انجام گردید.

    مواد و روش کار

    در این پژوهش، از دی اکسید تیتانیوم و مخلوط دی اکسید تیتانیوم و کربن فعال پودری محلول در آب مقطر جهت ساخت بستر فوتوکاتالیتیکی و بستر جذبی- فوتوکاتالیتیکی استفاده شد. لایه نشانی بسترها به روش غوطه ور سازی بستر پشم شیشه انجام شد. بررسی توزیع سایزی ذرات و کیفیت لایه نشانی به روش میکروسکوپ الکترونی انجام گردید. کارایی اکسیداسیون فوتوکاتالیتیکی تولوین در دو رآکتور مجزا در حضور تابش فرابنفش مورد بررسی قرار گرفت. طراحی آزمون ها به منظور بررسی تاثیر غلظت اولیه تولوین و گذر حجمی جریان بر کارایی حذف فوتوکاتالیتیکی در سیستم های فوتوکاتالیتیکی و جذبی-فوتوکاتالیتیکی با استفاده از روش سطح پاسخ  (RSM)انجام شد.

    یافته ها

    نتایج نشان داد که راندمان حذف و ظرفیت حذف تولوین در بسترهای فوتوکاتالیتیکی و جذبی- فوتوکاتالیتیکی متاثر از گذر حجمی جریان و غلظت ورودی آلاینده به سیستم بود. در شرایط بهینه عملیاتی، راندمان حذف در بسترهای فوتوکاتالیتیکی و جذبی- فوتوکاتالیتیکی به ترتیب در بارگذاری 84/5 و 1/65 میلی گرم به ازای متر مکعب در ثانیه و زمان ماند 2 و8/5 ثانیه، 99/98% و 95/14 % به دست آمد و ظرفیت حذف نیز در نقاط بهینه عملیاتی در دو فوتوکاتالیست جذبی و غیر جذبی 5008/71 و 1204/85 میلی گرم به ازای هر متر مکعب در دقیقه بود.

    نتیجه گیری

    بسترهای حذف فوتوکالیتیکی از کارایی خوبی در زمینه حذف ترکیبات آلی در محیط های داخلی، برخوردار هستند. تلفیق آنها با جاذب های سطحی منجر به توسعه بسترهای خودپالای جذبی-کاتالیتیکی می شود که ظرفیت حذف آلاینده را تا 5 برابر بسترهای کاتالیتیکی بهبود بخشیده و زمینه ساز کوچک سازی بستر کنترلی و  امکان استفاده از آنها را در سیستم های تصفیه هوای خانگی و صنعتی فراهم می نماید. افزایش کارایی حذف در بسترهای جذبی- فوتوکاتالیتیکی با افزایش هواگذر به دلیل کاسته شدن از ضخامت لایه مرزی و بهبود انتقال جرم از جریان هوا به سایت های جذبی و کاتالیتیکی می باشد.

    کلیدواژگان: کیفیت هوا در محیط های داخلی (IAQ)، دی اکسید تیتانیوم (TiO2)، کربن فعال، ترکیبات آلی فرار، تولوئن، اکسیداسیون فوتوکاتالیتیکی، بستر جذبی- فوتوکاتالیتیکی
  • بهزاد فولادی*، عباس محمدی، علی راستین، کامبیز احمدی، فرامرز قره گوزلو صفحات 88-97
    زمینه و هدف

    منابع روشنایی فلورسنت رایجترین منابع جهت تامین روشنایی در محیط های اداری می باشند و اخیرا منابع دیودهای منتشر کننده نور (ال ای دی) بعنوان گزینه روشنایی برای کاربردهای اداری مطرح شده اند و احتمال جایگزین شدن آنها با منابع فلورسنت در آینده وجود دارد. هدف از مطالعه حاضر، مقایسه اثر منبع روشنایی فلورسنت و ال ای دی بر سطح هوشیاری افراد می باشد.

    روش بررسی

    در این مطالعه مقطعی 28 نفر (8 زن و 20مرد) با میانگین و انحراف معیار سنی 7/4 ± 18/25 سال، بصورت داوطلبانه مشارکت داشتند. پیش از آزمون هدف مطالعه برای مشارکت کنندگان تبیین گردید. هر شرکت کننده در دو آزمون تحت نور چراغ فلورسنت و  هم چنین نور ال ای دی مورد دو سنجش (ارزیابی ذهنی آسایش بینایی و ارزیابی سطح هوشیاری) قرار گرفت. پرسشنامه بررسی روشنایی اداری برای ارزیابی ذهنی آسایش بینایی داوطلبان مورد استفاده قرار گرفت. هم چنین برای ارزیابی سطح هوشیاری شرکت کننده ها از دستگاه ثبت امواج مغزی (الکتروآنسفالوگرام) مدل نکسوس - 4 استفاده گردید. مطابق با راهنمای اندازه گیری روشنایی ایران میزان روشنایی هر یک از منابع روشنایی با استفاده از دستگاه لوکس متر تعیین گردید. جهت تحلیل یافته ها از آمار توصیفی و هم چنین آزمون تی- تست با استفاده از نرم افزار SPSS نسخه 18 با سطح معناداری 05/0 استفاده گردید.

    یافته ها

    نتایج مطالعه نشان داد که تنها سوالات 2 (بطورکلی میزان روشنایی این اتاق راحت است)، 3 (رنگ لامپ این اجازه را به من می دهد تا کارهای مختلف را به راحتی انجام دهم) و 4 (رنگ پوست من در زیر نور این چراغ طبیعی به نظر می رسد) پرسشنامه بررسی روشنایی اداری اختلاف معناداری را در ارزیابی ذهنی آسایش بینایی ناشی از منابع نوری فلورسنت و ال ای دی نشان دادند. هم چنین در زمینه ترجیح دادن نور منابع روشنایی،  چراغ فلورسنت 83/66 امتیاز  و چراغ ال ای دی 83/51 امتیاز را کسب نمودند. که این اختلاف از لحاظ آماری معنی دار بود. از نظر آسایش بینایی نیز نور فلورسنت (1/68 امتیاز) در مقایسه با نور ال ای دی (33/67 امتیاز)، منبع نوری راحت تری قلمداد شد، ولی از نظر آماری اختلاف معنی داری بین این دو منبع روشنایی در این خصوص مشاهده نگردید. میانگین توان نسبی باندهای فرکانسی آلفا، بتا و گامای ثبت شده توسط الکتروانسفالوگرام افراد در مواجهه با منبع نوری ال ای دی نسبت به منبع نوری فلورسنت، بالاتر بود. بعلاوه، میانگین توان امواج آلفا و بتا ثبت شده برای دو منبع فلورسنت و ال ای دی به ترتیب برابر 154، 225، 223 و 241 میکرو ولت بود. که از لحاظ آماری اختلاف معنی دار بیان گردید.

    نتیجه گیری

    مطالعه حاضر با رویکرد سنجش کمی و کیفی صورت پذیرفت که مطابق نتایج مشخص گردید که افراد مشارکت کننده نور حاصل از منابع روشنایی فلورسنت را بیشتر ترجیح می دهند و احساس بهتری را تحت مواجهه با نور فلورسنت در قیاس با نور منابع ال ای دی بیان داشتند. هم چنین روشنایی تامین شده توسط منابع ال ای دی اثر نامطلوبی در فرایند هوشیاری افراد نشان داد.

    کلیدواژگان: روشنایی، سطح هوشیاری، الکترو آنسفالوگرم، فلورسنت، ال ای دی
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  • Reza Kiantaj, Ali Ramezani*, Nahid Amrolahi Pages 1-13
    Background and aims

    Today, the safety culture in the High-Reliability Organizations (HRO) across various industries of a country is described as a long-term competitive advantage that can be considered as a factor in preventing costly events for organizations and countries. Therefore, promoting safety culture in such organizations can be weighed up as one of the main concerns of the organization and government managers and regulatory agencies. So how can industry managers, regulatory agencies and government officials help the organizations improve their safety culture? According to the results of this paper, the established processes of knowledge management system after sufficient time can enhance the organization's safety culture and help managers in this way. In this paper, we examine the relationship between the knowledge management system and the safety culture variables among Iran's nuclear reactors staff.According to the majority of safety culture scholars, Schein's organizational culture model (1992) has been used to address the safety culture in this research. Schein defines organizational culture: "A pattern of shared basic assumptions that the group learned as it solved its problems of external adaptation and internal integration that has worked well enough to be considered valid and, therefore, to be taught to new members as the correct way to perceive, think and feel in relation to those problems." Guldenmound (2000) declares: "In the way, Schein conceives and defines (organizational) culture, there is no need for a specific definition for safety culture. Basic assumptions permeate throughout the organization, including its aspect of safety." So safety culture can be treated as one aspect of the entire organizational culture. What comes from Schein's definition of organizational culture is that any cultural constructions and cultural activities in an organization or industry have to deal with collective learning. As a consequence, any efforts to enhance the safety culture of an organization should lead to positive learning experiences and cross the organizational learning membrane. Subsequently, these positive experiences gradually will penetrate to the organizational learning membrane and mix with the basic assumptions of organization members at this time new cultural assumptions will emerge.The authors believe that knowledge management systems in organizations can be used as the most effective tools for acquiring new knowledge and facilitating their learning. So that organizations via knowledge management systems can acquire knowledge and the culture of knowledge (according to practice-based perspective to knowledge) to develop their culture or promote their safety culture. For this reason, the implemented knowledge management system in an organization can be seen as a factor in promoting the concept of safety culture in that organization. Consequently, it is expected that a positive correlation is observed between these two variables over a relatively long term period. In this research, the knowledge management system has been considered in an exogenous construct and a reflective model about its core processes and safety culture variable. The reason behind this model is that the concept of knowledge management can exist as a pure entity in the organization because according to the perception of authors from the concept of practice-based perspective to knowledge the epistemology of knowledge management is related to organizational learning not to some processes in the organizations. This notion of knowledge management is opposed to the objective perspective and calls for a deeper understanding of learning and knowledge in organizations.

    Method

    The research data were collected from employees in Iran nuclear reactors located in Tehran, Isfahan, Arak and Bushehr cities using a paper questionnaire. In these facilities, responses were acquired from 98 respondents, representing the tow functional sectors of the organization: 1- safety-related sections like HSE and radiation protection sectors 2- other operating sections like engineering, technical support, and sectors that are engaged in core operation of the organization. The respondents were categorized as follows: 30 (30 percent) were technicians; 56 (56 percent) were experts; 12 (12 percent) were supervisors; With regards to gender all respondents were (100 percent) male.Knowledge management processes were measured by inquiring the respondents to reply to a set of items on a scale from 1 to 7 (1 completely disagree, 7 completely agree). These 25 Items were drawn from the Organisational Renewal Capability Inventory survey (Kianto, 2008).  Kianto (2016) states that: “In sum, the literature typically identifies four to six knowledge management processes that are cyclically interrelated. Similar to these views, this paper proposes that KM processes can be divided into five main types: knowledge acquisition, knowledge sharing, knowledge creation, knowledge codification, and knowledge retention. Although these types are, to some extent, interrelated and overlapping, and are cyclically interrelated, they are individually distinguishable because of their different foci.” The scale for knowledge acquisition tested the significance and fluency of knowledge acquired from extra-organizational sources, while the scale for knowledge sharing pointed horizontal knowledge flows inside the organization. Knowledge retention addressed the constancy and conservation of knowledge inside the organization. Items for knowledge creation addressed the periodicity and the foundation of new idea development in various groups of activities. Items for knowledge codification looked at the amount of documentation and storage and the scope of knowledge repositories.To measure the construct of safety culture, respondents were asked to answer questions similar to the one on the previous scale from 1 to 7 (1= strongly disagree and 7= strongly agree). These questions were drawn from the IAEA's 2017 Safety Culture Perception Questionnaire for License Holders (IAEA SCPQ-LH, 2017). The IAEA Safety Culture Perception Questionnaire for License Holders (SCPQ-LH) is one of five data collection methods used by the International Atomic Energy Organization to perform safety culture assessments. The questionnaire has been developed by an international group of experts with skillfulness in organizations safety culture, nuclear safety issues and questionnaire development, chaired by Dr. Mark Fleming, St Mary’s University, Canada.The data were analyzed with structural equation modeling (SEM), directed using the partial least squares (PLS) package (version 3 of SmartPLS). The first step was to assess the validity and reliability of the measurement model. Subsequently to test the hypotheses and examine connections between the study variables the structural model was used. In addition to testing the research model, the authors wanted to assess the relationship between knowledge management processes and safety cultures in more detail so the research model was tested for three groups of employees: 1- whole sample data 2- safety-related employees (like HSE or radiation protection sections employees, N=46) 3- operator related employees (like engineering and technical support or various operator groups sections, N=52).

    Results

    According to this research findings, knowledge management processes accounted for nearly 57 percent of variance for whole employees. Therefore, establishing knowledge management processes in a high-reliability organization like nuclear reactor operators is significantly linked with safety culture. Interestingly, severity of this relationship differs as a function of job characteristics and the type or content of knowledge that is to be found in the scope of the knowledge management system for that group of employees because knowledge management processes explained a larger amount of the variance of safety culture (62 percent) for safety-related employees and a smaller amount for other operator employees (53 percent). For this reason, phrases like Nuclear Knowledge Management (NKM) or safety-related knowledge management which is used in the International Atomic Energy Organization or other national or international institutions is justified and acceptable. In addition to this, organizations can enhance the safety culture by using design for their knowledge management system and emphasizing the development and dissemination of safety knowledge in the organization. This type of knowledge management system may be referred to as a strategic knowledge management system for safety.The consistency of the results obtained from the reflective model for knowledge management and failure to obtain reliable and meaningful results for the model in which the knowledge management construct was applied endogenously in the formative model with its indicators can be seen as evidence of the validity of the reflective model used in this study. It should be noted, indicators in the reflective models are manifestations of the constructs whereas indicators are defining characteristics of the constructs in the formative models. And from item relationships with construct antecedents and consequences point of view, indicators are required to have the same antecedents and consequences in a reflective model. Conversely, indicators in the formative models have not the same antecedents and consequences. It points out, this variable should be considered as a deep and independent concept in the organization that relates to deeper concepts such as organizational learning and organizational culture and must be evaluated with an impact on organizational learning.

    Conclusion

    To summarize, the real learning in organizations is a subject that occurs in deep organizational layers (according to Shine's organizational culture model) and the actual results of knowledge management systems should be sought in influencing these layers and points issue can lead to a more comprehensive definition of the concept of knowledge management in organizations with regard to its impact on organizational learning and other contextual issues such as organizational culture. This capability of the knowledge management system makes it as an agent in improving issues such as safety culture in the industries of countries.It should be noted that the results of this study cannot be directly used as a degree to evaluate safety culture in these facilities. The lack of women in this study was one of the constraints of this study that could be covered in future surveys with access to more employees.

    Keywords: Safety culture, Knowledge management, organizational culture
  • Reza Ramezanian*, Seyed Saeed Hasanolhosseini Pages 14-29
    Background and aims

    Given the ever - expanding growth of science and technology that the multiplicity, variety, and complexity of industrial processes have been only a part of it, and despite the many human needs to be met using science and technology, the devastating effects must not be forgotten. These consequences are either due to the unknown dimensions and aspects found in modern science and technology or the result of mismanagement, illness and work - related accidents. Among these effects and consequences are environmental consequences. Research shows that occupational accidents are among the most important consequences of globalization, especially in developing countries. On the other hand, the environment has suffered from the pollution caused by industrial and manufacturing centers to the extent that the pervasive environmental crises such as gradual warming, stratospheric ozone depletion, acid rain, depletion environmental crises such as gradual global warming, stratospheric ozone depletion, acid rain, depletion of water oxygen and aquatic death, soil degradation caused by waste and chemicals and, to some extent, noise pollution, result from unequal confrontation between industry and environment. Health, Safety, and Environment (HSE) management is responsible for planning, implementing, monitoring and optimizing operational processes in the areas of environmental management, health protection and occupational safety. Regulatory requirements play an important role in HSE discipline. Considering the threats posed by industry and the imposition of heavy and increasing costs on the economy of human society, and considering the importance and role of Health, Safety, and Environment - Management System (HSE-MS) in protecting these two infrastructure components, and of course, highly influential manpower and the environment in the field of industry and production and more importantly sustainable development, it is imperative to evaluate optimally and realistically its performance in industries and manufacturing centers.The effects and consequences of the devastation caused by the dangers and aspects of the HSE have become so tangible and visible that they have prompted national, and international agencies to respond these issues since the mid-1990s. These reactions occur in many forms, including the creation and dissemination of standards and management systems. The standardization approach in the field of HSE was a response to the needs of organizations and stakeholders that sought to manage HSE in a more sustainable and effective way in order to reduce the number of events (accidents), occupational injuries and diseases, mitigate environmental aspects and consequences.Ranking is a type of qualification criterion based on defined standards and is intended to guarantee the quality and quantity of contractors in providing services and defending the rights of stakeholders and users. Integrated fuzzy analytical hierarchy process (FAHP) and Taxonomy techniques as a method in multi criteria decision making (MCDM) helps decision maker(s) to organize and analyze problems, and to rank alternatives. Identification of criteria and indicators, selection of measures and weighting of indicators which with HSE-MS performance evaluation are the purposes of this study. Then, developed method is applied to rank the 5 actives organizations in boat industry.

    Methods

    This applicable study was done as a descriptive-analytic procedure. Graduates of HSE related fields with career in HSE performance evaluation are the statistical population of this research. The number of samples was 8 experts that according to the sampling method - nonprobability, purposive (or judgmental) and convenience - was in correspondence with the purpose of this paper. To incorporate the experts' knowledge and experience in presenting their opinion, we weigh the experts based on their educational background, HSE experience and HSE performance evaluation and determine their significance coefficients and incorporate these coefficients into the data extracted from the questionnaires. ISO 14001 : 2015 (Environmental Management Standard) and ISO 45001 : 2018 (Occupational Safety and Health Management) standards and collegiate related courses – industrial safety engineering, occupational hygiene engineering and environment engineering/management - were basement to identify the HSE-MS criteria and indicators. After identification, in order to quantify HSE-MS performance evaluation, some measures were determined and made available for experts. Then, experts weighted them which weighting using FAHP approach with EA method. Finally, performance evaluation of HSE-MS is done by Taxonomy method in 5 actives organizations in boat industry. All experts have experience in the field of HSE performance evaluation. According to the content, approach and goals of the research, the data collection tool is a questionnaire. As ISO 14001 : 2015 (Environmental Management Standard) and ISO 45001 : 2018 (Occupational Safety and Health Management) standards are used to identify indicators and indicators are derived from standard clauses and each standard clause represents a specific topic, so each indicator exclusively represents one of the standard clauses. This is also indicative of the validity of the indicators.The properties of a suitable criterion can be divided into two categories: inner and outer. Internal characteristics are related to the components and internal dimensions of a criterion, while external features refer to the type of relationship between the criteria. A good criterion should have features such as: quantitative, valid, representative, minimal variability of performance measurement results under the same conditions, sensitive to change, cost-effective, understandable to most users Considering the inner and outer criteria while selecting the features will lead to a comprehensive selection that will prevent the selection of additional indefinite features along with full coverage of the HSE-MS dimensions and elements. Based on ISO 14031 : 2013 (Environmental Performance Assessment Standard), we considered two types of managerial and operational indicators for the comprehensiveness of HSE-MS performance evaluation. We determined managerial indicators according to the ISO 14001 : 2015 (Environmental Management Standard) and ISO 45001 : 2018 (Occupational Safety and Health Management) and also operational indicators are set based on key courses of HSE related academic disciplines. To quantify the performance evaluation of the HSE-MS, we need to use quantitative indicators or in other words we should apply a measure for this purpose. The researchers suggested two measures in the HSE Qualitative Questionnaire for each indicator and experts had to select one of the two measures or introduce another one. In terms of weight of experts, the final measure is selected for each feature. In order to determine the effect or weight of each of the indicators on the performance evaluation of HSE-MS, we need to determine a method for weighting. Accordingly, the fuzzy analytic hierarchical process approach was developed to determine weight of the indicators. According to the selected method, a questionnaire called pairwise comparison matrix of indicators / measures was given to the experts based on triangular fuzzy numbers to determine each of the pairwise comparisons between the indicators according to the fuzzy linguistic expression.

    Results

    By reviewing the literature and receiving expert’s opinions, 10 general criteria and 54 indicators were identified so that the total number of identified management performance criteria and indicators are 7 and 28 respectively and also total number of identified operational performance criteria and indicators are 3 and 26 respectively. Management performance criteria include organizational environment, leadership, planning, support, operations, performance evaluation and improvement. Operational performance criteria include safety, health and environment. Nonetheless, the total weight of management and operational performance criteria is 40.5 and 59.5 respectively. Despite the higher number of management performance criteria, weights and importance of operational performance criteria for assessing HSE-MS performance is much more. Three operational performance criteria have largest weights based on experts’ opinions. The three operational performance criteria are assigned the highest weight followed by the management performance criteria. Among the management performance criteria, the improvement criterion is with the highest weight and the criterion of the organizational environment is with the least weight. Also, among the 54 identified indicators, the first six indicators (include product, particles, gases / vapors, machinery and equipment safety, biologically permitted hazardous agents, general safety (5S)) with the highest weight are all operational performance indicators and the last six indicators (include partnership, consultancy, organizational roles, responsibilities and organizational authorities, planning actions to achieve HSE objectives, internal audit, procurement and communications) with the lowest weight are management performance indicators. The obtained results using integrated method revealed that the organization 1 in boat industry has been placed in the top lists. Also, the results showed an influence of indicators weight on ranking of organization that considering this issue in performance evaluation of organizations especially in HSE-MS is the suggestion of this research.

    Conclusion

    While confirming the need for management and operational performance indicators to realistically evaluate the HSE performance of industrial organizations, this study emphasizes that the weight of operational performance indicators is higher than that of management - despite the higher number of management performance indicators. Obtained results showed that the integrated fuzzy analytical hierarchy process and Taxonomy methods can be used to evaluate the performance of Health, Safety, and Environment - Management System successfully. It seems that, performance evaluation with multi criteria decision making methods with employee's collaboration can increasingly leads to effectiveness in using HSE-MS. In order to improve the HSE performance of industrial organizations, the implementation of the relevant standards, including ISO 14001 : 2015 and ISO 45001 : 2018, must be such as to ultimately eliminate, reduce or contain safety hazards, adverse health factors and environmental consequences.

    Keywords: Performance evaluation, Health, Safety, Environment Management System (HSE-MS), Fuzzy Analytic Hierarchy Process (FAHP), Taxonomy
  • Hamide Niknazar, Amirhoushang Mehrparvar, Mostafa Behjati, Ali Dehghani, Mohammad Javad Zare* Pages 30-39
    Background and aims

    Currently, as a result of research on laboratory animals, abundant information has been obtained on the impact of various environmental factors on the occurrence of congenital malformations, but there is still no comprehensive information on the causes of congenital heart malformations (CHD) in human populations. Congenital heart defects (CHDs) constitute the major class of congenital anomalies. Although the incidence of CHDs is close to one percent of live births, its prevalence in the fetus is higher. The prevalence of CHDs is 0.5-0.8% in the live-term neonate, 2% in premature infants and 10-25% in the aborted fetus. The exact causes of CHDs are not clear. About 25% of all CHDs are attributed to the genetic factors. The interaction of genetic and environment is also considered in the etiology of the CHDs. Researchers say occupations such as pharmacy, chemical engineering, dyeing, increase the risk of neonatal eye, heart and intestinal defects and cleft lip and palate. Several studies have shown the effect of non-genetic factors such as environment and lifestyle on the occurrence of CHDs. In the Snijder study, no relationship was found between maternal occupational contact and CHD offspring, whereas fathers' exposure to phthalates increased CHD in neonates. According to the above mentioned content Identify paternal exposure to solvents and its relationship with congenital malformations heart defect can be effective in identifying the factors affecting the incidence of malformations. However, there is no consensus on the role of paternal and maternal exposures and susceptible window of exposure on the CHDs across studies. Additionally, the body of evidence on the association between occupational exposures and congenital malformations especially CHDs are limited. This study aimed to investigate paternal occupational exposure to solvents and congenital heart abnormalities in neonates.

    Methods

    The study was approved by the Ethics Committee of Shahid Sadoughi University of Medical Sciences (Registration Code: ir.ssu.medicine.rec.1359.37). In this case-control study 200 children with congenital heart defect and 400 matched healthy infants were considered as case and control groups respectively. Cases were randomly selected from the medically diagnosed and registered CHDs newborns during 2015-2017 (1393-1395 Persian year) in Yazd, Afshar referral hospital. Controls were selected from healthy newborns of Yazd province referred to the Yazd city health centers for receiving their routine health care services. Controls were matched case by case with the cases in term of age. A researcher-made questionnaire was used to collect the data by the telephone interview. The questionnaire comprised of three sections including a) general items regarding demographic characteristics b) lifestyle of parents and c) occupational and environmental exposures of the parents. Information on paternal occupation of questionnaires and paternal occupational exposure was performed using job exposure matrix. For this purpose, a matrix of occupational exposure assessment of solvents was prepared in Excel software. Exposure ratings of each job were solved based on the opinions of 10 experienced and well-known occupational health professionals. After completing the job matrix, the mean score of solvent exposure was calculated and the mean scores were used as fathers' exposure to solvents. Outcomes definition was performed according to international Classification of Disease version 10 (ICD 10). All refereed children with maximum three years of age which were diagnosed with at least one of CHDs according to the ICD10 classification were entered into the study.  Data were analyzed using SPSS16 software, descriptive and inferential statistics such as frequency and percentage. STATA14 software was used to evaluate job contact and logistic regression tests were used to estimate odds ratios and odds ratios. 95% confidence interval and 0.05 were considered significant.

    Results

    Among the analyzed cases, ventricular septal defect with 31.5% (n = 63) and patent ducts arteriosus with 24% (n= 48), had the highest prevalence. Results showed that mothers of case group had lower level of education compared to control group (p-value <0.001). In this study, the sex ratio of girls to boys was 1/1.06. The BMI in mothers in the case group (26.61± 5.74) was significantly higher than the mothers BMI in the control group (25.06± 3.71). Eight percent increase in the risk of CHDs was found per one unit increase in the BMI in the crude model (95% CI: 1.04:1.13). Eight percent increase in the risk of CHDs was found per one unit increase in the BMI in the crude model (95% CI: 1.04:1.13). About 72% (n=144) of mothers in the case group and 83% (n=332) in the control group reported no history of a diagnosed medical problem during their pregnancy. Significant difference was observed between the frequency of heart problems in the newborns of mothers with and without health problems during pregnancy (OR: 1.83; 95% CI: 1.23: 2.74). 26.5% (n=53) of the mothers in the case group and 21.25% (n=85) in the control group were a passive smoker. However, the risk increase due to passive smoking was not statistically significant (OR: 1.34; 95% CI: 0.90: 1.98). Use of folic acid during pregnancy was associated with 41% lower risk of CHDs (95% CI: 0.30: 0.86). Use of Iron supplement during pregnancy was also associated with 40% lower risk of CHDs (95% CI: 0.36: 0.99). Familial history of other congenital anomalies and also CHDs was associated with increase in the odds of CHDs. The prevalent of Paternal occupational exposure to solvents was 66% and 55% in the case and control groups respectively in which relationship was statistically significant (OR = 1.53, 95% CI = 1.06-2.21). After a removing the effect of confounding factors the significant differences was not observed between paternal exposure to solvents and heart defects in child (AOR = 1.28, 95% CI = 0.84-1.6). Investigation of the relationship between patent ducts arteriosus and occupational exposure to solvents showed that fathers' occupational exposure to solvents was higher in the case group (72%) than in the control group (58%), whereas between arterial openness and occupational exposure to solvents. With and without confounding factors, no significant relationship was observed despite high index ratio (OR: 1.94 4- 95% CI: 0.97-94.09 and OR: 64% CI95: 0.76- 3.55 / 1: AOR))

    Conclusion

    The limitations of the this study were the small number of samples, the limitation of study to a specific timeframe, use of the job evaluation matrix alone and the lack of evaluation of solvent biomarkers in parental and fetal body tissues and fluids. Despite the limitations of the study, the findings of the study showed that one of the environmental factors affecting the fetal health was occupational exposure Father’s with solvents. therefore father's job may affect the child health.  the results of Studies have also shown that exposure to chemicals reduces the quality of semen and can affect epigenetic planning during sperm cell maturation. These changes may lead to abnormal gene transcription in fetal tissue that may later lead to congenital defects. In addition, occupational exposure to chemicals is generally much higher than exposure to such substances in the diet and the environment, which may further impact such exposure. An animal study has also shown that the cardiovascular system in Fetal growth stage is highly sensitive to many environmental contaminants such as dioxins, polycarbonate biphenyls and some pesticides. In this way, training parents about compliance with occupational safety standards can increase the health of next generation. Also, since this study was conducted as a job and solvents are highly diverse, it is recommended to study the effect of each solvent on the biomarkers and the effect of each solvent.

    Keywords: Congenital Heart Defects, Solvents, Occupational Exposure, Paternal Occupational Exposure, Job Exposure Matrix
  • Mohammad Amin Rashidi, Roohalah Hajizadeh, Mohammad Hossain Beheshti, Azim Akbari, Abdolhossein Poornajaf, Ali Khavanin*, Masoud Poornajaf, Fereshteh Nickvand, Yoosef Faghihnia Torshizi Pages 40-51
    Background and Objective

    Inappropriate atmospheric conditions are harmful factors that cause particular problems in certain seasons (summer or winter). The occupation of confectionery in the regions like Ilam causes severe problems due to the heat generated by the nature of the work (synthetic heat-generating processes) and the heat resulting from the climatic conditions in the region. Exposure to excessive heat, in addition to disrupting the physiology and health of the individuals that may cause many diseases and complications, also affects their efficiency and safety. One of the indices of heat stress is the WBGT index, confirmed by various national and international organizations and institutions as the standard method for measuring heat stress. WBGT index engages important environmental factors directly or indirectly in its computational structure. The Discomfort Index (DI) has been recommended for more than four decades along with the WBGT index for the evaluation of warm environments. Today, the oral temperature is used to determine the heat stress and strain. In addition, oral temperature is one of the important parameters for the validation of indices. Therefore, in order to prevent the occurrence of heat stress complications in occupational environments, a study was conducted to determine the amount of heat stress in the employees of confectionery workshops in Ilam city, so as to identify the factors affecting the heat stress of workers and to provide recommendations for the reduction of these risk factors and to create a healthy working environment.

    Methods

    This descriptive-analytical study was carried out on 104 workers in 35 confectionary workshops in summer of 2017. The sample size was selected based on census method. Prior to the study, the workers were monitored through medical records and interviews, and, two of them did not qualify for inclusion in the study. Measurement of the study variables was performed at the hottest work hours (10 to 14), once for each worker, in the worst workstation (nearest to the heat source). In the present study, four groups of occupations, i.e. workers of oven, mixer, flattener, cleaning and packaging, three types of ovens, i.e. layered, winch and furnace, and three productions of wet and dry pastry, cake and French bread, Baghlava and Ka’ak. Assessment of heat stress was performed by the WBGT (based on ISO7243 standard) and the DI indices. Metabolism and activity of workers were calculated according to the ACGIH standard. Also, the working pattern was 75% of the work-25% of the rest, and according to ISO 9920, the clothing insulation coefficient in WBGT calculations was 0.6 clo. Along with the environmental parameters such as dry bulb temperature, natural wet bulb temperature, globe bulb temperature, relative humidity and dew point temperature, the oral temperature of the workers was measured by a digital medical thermometer. Finally, data analysis was performed using SPSS v.22 and statistical tests of Kolmogorov-Smirnov, Mann-Whitney, Kruskal-Wallis, one-way ANOVA and Pearson correlation were performed.

    Results

    Findings of this study showed that the mean of WBGT index in the workers of oven, mixer, flattener, cleaning and packaging was 33.66±3.96, 29.58±3.05, 31.73±3.61 and 29.87±2.4. Also, this index was 30.94±3.86, 34.14±3.89, and 32.2±2.91 for the winch (wet and dry pastry), layered (cake and French bread), and furnace (Baghlava and Ka’ak) ovens (products). These results show that the amount of heat stress in working with the oven and the cake and French bread product (layered oven) was more than others. Kruskal Wallis tests and one way ANOVA showed a significant difference between the mean of WBGT and DI indices with job variables, type of oven and products (p <0.05). A 95% confidence interval was observed in terms of the WBGT index between the subgroups of the oven and flattener, oven and cleaning and packing, layered oven and winch oven, and French bread and the wet and dry pastry. However, in terms of the DI index, this difference was found between the sub-groups of the oven and cleaning and packing, oven and mixer with flattener, layered oven and winch oven, and French bread and the wet and dry pastry. Pearson correlation test showed that there was no significant correlation between oral temperature and indices and variables (p<0.05). Based on the results of this study, the mean of WBGT index at the heights of head, waist and ankle was 32.54±5.01, 31.54±3.86 and 30.49±3.12, respectively. Also, according to Kruskal Wallis statistical tests and one way ANOVA, there was a significant difference in WBGT index and dry bulb temperature, natural wet bulb temperature, globe bulb temperature and relative humidity at the heights of head, waist and ankle (P <0.05). The results of the Mann-Whitney test indicated that there was a significant difference between the gender variable and the oral temperature (p <0.05), with the mean of this variable was higher in women (36.7±0.27) than men (36.42±0.84). The results of this study showed that 85.6% of the subjects had a “severe” discomfort index (DI), and regarding the WBGT index, 14.4% and 85.6% were lower and higher than the threshold, respectively.

    Conclusion

    According to the results, almost all of the workers in the confectionary workshops are exposed to heat stress, but subgroups of oven, mixer, layered oven (cake and French bread), furnace oven (Baghlava and Ka’ak) and the females were exposed to higher stress. So, these subjects have a priority when adopting control measures. It is recommended that measures such as pre-employment examinations, preparation of proper drinks, training the workers, reduction of working time, using thermal shields, using air conditioning system, and paying particular attention to reducing the wet temperature and relative humidity of the workplace are taken to minimize the exposure to heat and the resulting diseases.

    Keywords: heat stress, WBGT index, DI index, the employees of confectionary
  • Abolfazl Ghahramani*, Elias Taghizadeh, Iraj Mohebbi Pages 52-61
    Background and aims

    Occupational Health and Safety (OHS) regulations have been developed with the aim of crating safe conditions at workplaces. Employers are required by OHS laws to provide a safe working environments for employees. A common method to manage OHS in many workplaces is to enforce the requirements of the OHS regulations from inside and outside the organizations. Implementation of the OHS regulations plays a major role in enhancing OHS status in organizations, and safety management approaches emphasize on the compliance with the requirements of the regulations. However, studies show that OHS regulations are not fully implemented in workplaces, especially in the companies that located in developing countries. Therefore, assessing how organizations comply with the requirements of OHS regulations can help policymakers and managers to identify existing problems and to plan for better management of OHS. The Code of Committee for Technical Protection and Health at Work (CTPHW) has emphasized on the formation of committee meetings. According to the code, OHS issues in workplaces must be reviewed in the meetings so that decisions can be made to improve the status of OHS in organizations. The formation of OHS committees in workplaces has been associated with reduction of occupational injuries, facilitating senior management cooperation with workers, increasing worker participation in OHS affairs, and overall improving OHS status. Conversely, the lack of formation of OHS committees can lead to the absence of OHS policies and programs in workplaces.The collection, investigation, and reporting of occupational injury’ data is one of the important requirements of the CTPHW regulation. Recording and storage of OHS data can help to preserve the OHS knowledge of an organization and provide insights into the organization's OHS performance. However, occupational injuries as an imperative OHS data not properly reported to the relevant OHS enforcement agencies i.e., OHS authorities (Labor inspection offices and health centers) in Iran. Given the importance of establishing CTPHW in improving OHS, reviewing the available related documentation can lead to the identification of problems linked with the implementation of the regulation and providing comments for better implementation of it in the future.Analysis of OHS documentation in workplaces such as CTPHW’ minutes can be done using qualitative and quantitative research methods. Document analysis is a systematic way to study and evaluate paper and electronic documentation. Same as other qualitative research methods, document analysis is an important research method to study and interpret data in order to know the meaning, understand, and acquire empirical knowledge. The data is organized into topics, quotes, and categories, through content analysis. Content analysis is a technique that is used to infer the specific features of a text in a systematic and objective manner. It is a process of organizing information into categories according to the main research questions. Content analysis is also useful in providing a raw picture of the data that determines the number of words used in the text.Literature review has shown that no research studies have ever been reported on how to enforce the CTPHW regulation in organizations and to review the content of relevant documents in scientific journals. Therefore, this study was conducted to investigate the content of the CTPHW’ minutes using a quantitative approach in manufacturing companies. It also aims to discover how the companies fulfill the requirements of the CTPHW code. 

    Methods

    In this qualitative study, the records of CTPHW’ minutes related to the years of 2011-2015 were collected from the manufacturing companies i.e. 34 firms. The companies located in one of the northwestern city of Iran. Manufacturing activities in the companies include the production of food and dairy products, building materials, gloves, auto parts, electricity, furniture, mattresses, and metal equipment. All studied companies had been hired full-time or part-time OHS officers before the time of the study.Most of the minutes used in this study were collected from the archives of an OHS authority and some were gathered from the archives of the manufacturing companies. The contents of paper and electronic documentations of CTPHW’ minutes were organized into topics and categories using a quantitative content analysis method and based on research questions. In order to analyze the data, each of the minutes was coded word by word. The terms and number of the words related to safety, health, and ergonomics and the type of related approved OHS promoting programs were determined. Also, the types of approved projects by CTPHW’ members were analyzed in three separate sections. In the first part, the projects were examined in terms of the types of methods used to control OHS risks, including engineering controls, administrative controls, work practices, and personal protective equipment (PPE). The projects were then reviewed for being routine or non-routine organizational practices for management of OHS. The plans were also examined according to the subjects of safety, health, and ergonomics. Each of the minutes was reviewed several times to determine the number and type of control plans approved by the members of the CTPHW in the companies, and then the plans were classified according to the type of control procedures. 

    Results

    The content analysis of the minutes showed that the highest number of them (241 cases) was related to 2015 and the lowest number (34 cases) was related to 2011. The total number of clauses was 4823; that the highest number of them (1431 clauses) was related to 2015 and the lowest number (383 clauses) was related to 2011. Thematically, the highest number of clauses was related to safety (2807 clauses) and the least was related to ergonomic (67 clauses). The total number of examined OHS related words was 4408; with the highest number (1271 words) was related to 2015 and the lowest number (515 words) was related to 2011. The highest number of words was related to safety (1353 words) and the least of the words related to ergonomics (31 words), and among the safety related words, fire-fighting word had the highest frequency. It should be noted that the number of ergonomic word in the years 2011 and 2012 was zero. The total number of approved projects was 2553, the most of them were related to engineering (958 cases) and the least were related to work practices (145 cases). The number of routine projects was 1217 cases and the number of non-routine projects was 1181 cases. Thematically, most of the projects were related to safety (1566 cases) and the least were related to ergonomics (41 cases). 

    Conclusion

    The findings of this study showed that the requirements of the CTPHW regulations were not properly implemented in the manufacturing companies. The number of minutes, clauses, and words was the lowest in 2011 and the highest in 2015. The safety topics had the highest frequency, and ergonomics had the least frequency in the analyzed minutes. Most of the control schemes adopted to reduce OSH risk were engineering controls. These findings indicated an increase in the number of minutes, clauses, and OHS control plans in the 34 studied firms during the studied years. The finding also demonstrates gradually improved compliance with one of the requirements of the CTPHW. According to the findings, this study emphasizes on more follow-up of OHS authorities to better enforce the requirements of CTPHW regulation in manufacturing companies. Training and encouragement of manufacturing companies by the OHS authorities can help to fulfill the requirements of the CTPHW code and the promotion of OHS status in the companies through making a proper culture of safety.

    Keywords: Qualitative study, Document analysis, Content Analysis, Safety, Enforcement
  • Jalil Derakhshan, Majid Motamedzade, Erfan Taherpour, Rostam Golmohammadi, Mohmmad Babamiri*, Maryam Farhadian Pages 62-74
    Background and Aim

    Noise is one of the most effective exogenous factors affecting the processing mechanisms of the human brain, which has a major role in the occurrence of human error and occupational accidents. Low frequency noise is usually produced by sources such as ventilation systems, pumps, compressors, diesel engines and gas turbines, and so on. For this reason, the sound is in addition to industrial environments such as control rooms, in residential, office, etc., and compared to high-frequency sounds, low frequency sound is less attention and the rules associated with its control Not satisfactory Low-frequency sound is one of the most important sources of sound-producing in the environment, and it is even annoying at low levels and affecting the cognitive function of individuals. These sounds are seen in both industrial and public environments. Because the levels of exposure to this sound are usually not very high, it does not attract much attention. Some of the individual differences, such as superiority, extroversion, neuroticism, and audible sensitivity, can reduce or increase the effect of sound on cognitive functions. The purpose of this study was to investigate the effect of handicapping on cognitive functions in the presence of low frequency noise.

    Materials and Methods

    The present study is an interventional type. The research population was Hamedan University of Medical Sciences students. 120 of them were selected through purposeful sampling (40 right, 40 doubly capable and 40 lepers). All tests were carried out at the Faculty of Health of Hamedan University of Medical Sciences in a room with acoustic and physical control in March 2012. The conditions for entry to the study include: Being between the ages of 20 and 30 years, not taking any drug that reduces the level of consciousness during the test, no color blindness, hearing loss (hearing loss below 25 dB), lack of background Cardiovascular disease, respiratory problems, and sleep disorders. In order to eliminate the interfering factors, an audiometric test was conducted at the Faculty of Health and Ishihara Blind test. Individual information and medical records were collected by a questionnaire and, if they did not have the criteria for entering the study, were removed from the community under study. After the final selection of eligible individuals, all tests were fully explained to the subjects. It should be noted that all the subjects participating in this study were verbally and oral.Chapman's hand-breaking questionnaire was used to determine the supreme hand. By simulating the real environment of each subject, exposure to high-frequency audibility in the industry (45 and 65dB) was exposed for 40 minutes. The environmental conditions were maintained under thermal comfort conditions, with an equivalent temperature of 18 ° C and a relative humidity of 50%, without constant disturbance of air flow. Also, with 500 lux and fluorescent lamps, the brightness level of the surfaces was well maintained and maintained during all experiments. In this study, the recorded sound of the industrial air conditioning system was used in the work environment using the Cool Edit Program In the desired frequency band, it was edited. This program is a powerful software for producing sound at different frequencies, especially low-frequency noise. When playing sound, the level of sound pressure level was measured at the ears of the subjects tested and sitting. The benchmark used in the SVANTEK research is the 971-based Polish-American company, which operates according to the IEC 61672 standard, which has the ability to analyze 1.1 and one-third of the octave band. Spherical shaped speakers with a SWA-100 amplifier to amplify low-frequency noise that produces similar sound to the work environment. And during exposure to IVA PLUS CPT, the cognitive functions (reaction time, attention, balance, concentration, and processing speed) of the subjects were examined. The cognitive performance tests lasted 10 minutes, from the minute 30 to 40 people responded. After the implementation of each step, the groups changed to eliminate the effect of the exposure sequence, and the interval between each experiment was 24 hours in order to prevent cumulative fatigue at the second level. Data were analyzed using SPSS v.20 software, Kruskal-Wallis test and variance analysis.

    Results

    The mean age of the subjects was 23.94 with a standard deviation of 3.35. The distribution of the tested subjects was only male, 85% of them were single and the rest were married. Most of the participants in the study were from health sciences and 80% of them were undergraduate. The results showed that there is a significant difference between cognitive functions of individuals with increasing voice level from 45 to 65 dB. Also, there is a significant difference between the components of cognitive function and hand holding (p <0.05), so that the right subjects of the components Better cognitive listening, and leftover subjects had better visual cognitive components than others, and the two-way performance was higher at the higher level than the other two groups (p <0.05).

    Conclusion

    The results of this study indicate that there is a significant relationship between side advantage and cognitive functions, thus, it was observed that during exposure to voice in leftover subjects, visual components of cognitive functions are more than right ones. Voice is effective on the mental activity of individuals, so that the differences between the components of cognitive functions when exposed to two levels of sound 45 and 65 dB with sound are quite obvious. According to the findings of this study, it can be concluded that by increasing the level of sound from 45 to 65 dB, the low-frequency sound (the intensities in the industry) can improve the cognitive functions in all three groups (right hand, left hand and two-way power). Slowly In the meanwhile, the performance of the two shafts is higher than the right-handed and left-handed ones. The results of this study indicate that exposure to low frequency noise was effective in the components of the cognitive functions of participants, and there was a significant relationship between the increase in noise and cognitive function components with hand holding. During the exposure to sound, the two sides had higher components of cognitive function. Accordingly, in work posts and sensitive occupational tasks requiring the use of cognitive functions, the effect of handicapping should be considered.

    Keywords: Low Frequency Noise (LFN), Handedness, Cognitive Performance
  • Samira Kazemi, Ali Safari Variani, Hadis Khoshnavaz, Ahmad Nikpey* Pages 75-87
    Background and aims

    Clean air is one of the most important components of health and sustainable development. Every person breathes about 10 kg of air per day and if it contains pollutants, it will have a serious impact on their health. Indoor air quality (IAQ) is one of the major health issues that have been addressed in recent years with changes in lifestyle patterns. Usually, due to the increased time of presence and activity in these environments and reduced air exchange with the outdoor environment, indoor air quality is poorer than outdoor environments. Toluene is a Volatile organic compound with widespread applications. VOCs has a high vapor pressure and high emission rate to environment. Due to its adverse effects on human and environment health, they must be controlled before discharging to the environment. Photo catalytic oxidation process is one of the environment-friendly and effective methods for the remove the organic compounds from the air which likely to be better in combination with other methods such as adsorption. Through the process of PCO, UV radiation adsorption on TiO 2 is associated with forming electron and holes from electron escape. The resulted electrons have got high levels of oxidation power and act as a strong oxidant producing superoxide ion. The resulted holes have good oxidation potential; with superoxide ions, they make good conditions for oxidation of most organic compounds to less hazardous compounds such as carbon dioxide and aqueous vapor.  The most important limitation of Photo catalytic oxidation process is the dependence of the contaminant removal on the surface chemistry and the residence time of the contaminant on the photo catalyst surface. The most important limitation of the adsorption method is the decrease in adsorption removal efficiency and elimination capacity due to the filling of the adsorption sites.According to this, by combining adsorption and photo catalytic oxidation, it is possible to increase the time of contaminant presence at photo catalytic oxidation sites and to enhance the surface chemistry and on the other hand, to restore the adsorption sites. This study is conducted with the aim at examining the effects of combination Activated carbon and Titanium dioxide (TiO2) on the toluene removal efficiency.

    Methodology

    In order to prepare samples, 5g of TiO2 and 5g of TiO2 and 1g of activated carbon dissolve in separate 100 ml distilled water under vigorous stirring. The surface modification was done by dip-coating method. The efficiency of the photocatalytic oxidation of toluene is evaluated in two separate reactors exposed to ultraviolet light. Additionally, to investigate the effect of initial concentration of toluene and airflow rate on the photocatalytic removal efficiency in photocatalytic and photocatalytic-adsorption beds, the RSM method was used to design experiments.Also, Scanning Electron Microscopy was used to determine catalysts surface morphology. First, to obtain the adsorption capacity in both reactors, with the UV lamp being off, the considered concentrations were added to the reactors in 2-5 L/m airflows. Then, adsorption capacity of adsorption beds were evaluated according to the time needed for the outlet concentration to reach 10% of the inlet amount, as the fraction point of the adsorbent and saturated capacity.Next, to compare the removal efficiency of toluene in the two reactors, the lamps were immediately turned on; concentrations were gradually decreased and when the outlet concentration was balanced, the data was collected.

    Results

    Images from an electron microscope of surfaces of the two catalysts showed that the distribution of nanoparticles on glass wool was similar and the particle size in the non-combined catalyst were smaller than 95 nm, and smaller than 87 nm in the adsorbent catalyst. In other words, the size of nanoparticles led to more contact area of the pollutant with the catalyst, increased reaction as well as removal efficiency. SEM photography confirmed that, combining Ti O2 with activated carbon, the pores in the activated carbon were occupied and it made a good place for Ti O2. Controlling the process of photocatalytic elimination in photocatalysts indicated that in TiO2-AC reactor, removal efficiency and elimination capacity of toluene were higher than TiO2 reactor and combining adsorbent with photocatalyst may lead to enhanced photocatalytic oxidation efficiency of organic compoundsThe results illustrate that the removal efficiency and elimination capacity of toluene in photocatalytic and photocatalytic-adsorption beds are Influenced by airflow rate and inlet concentration of toluene. In optimized operational conditions, the removal efficiency in both combined and non- combined reactors in inlet loadings of 84.5 and 1.65 mg/m3.s and retention time of 2 and 8.5 s, was 99.98% and 95.14%, respectively. Also, elimination capacity in optimized operational points in the two absorbent and non-absorbent photocatalysts was 5008.71 and 1204.85 mg/m3.min, respectively.  As the statistical analysis by Minitab indicated, in the concentration range of 10-40 ppm and the airflow of 2-5 L/min (in 2-8.5 s retention time) in the combined reactor, the removal efficiencies were 90% (min.) and 99% (max.); however, in the non-combined reactor, the minimum of removal efficiency was 10% and the maximum was 90%.The results of this study also indicated that the retention time had a significant effect on the removal efficiency and the elimination capacity of toluene, that is, at the constant inlet concentration (25 ppm) increased with increase in retention time of the non-composite reactor. However, in the adsorbent reactor, lower retention time led to higher removal efficiency. According to the results, toluene removal efficiency and elimination capacity levels in the combined reactor in time retentions of 2, 3.3 and 8.5 s increased compared to the non-combined reactor. Also, evaluation of the effects of initial toluene concentration on removal efficiency and elimination capacity showed that they were higher in the combined vs the non-combined reactor. Removal efficiency of both photocatalysts was influenced by the initial concentration of toluene, so that, in TiO2 higher inlet concentration led to lower removal efficiency. Nevertheless, in the adsorbent photocatalyst, there was an increase in removal efficiency with higher concentrations.According to the findings, the production of CO2 was dependent on toluene inlet concentration and the airflow. In the combined photocatalyst, the minimum and maximum of the produced carbon dioxide were 40 ppm and 80 ppm, respectively. And it was 84.82 in the optimum operational point (46.2 ppm; 5.62 L/min). However, in the non-combined reactor, the produced CO2 was 29.2 ppm in the optimum operational point and its minimum and maximum were 10 ppm and 25 ppm, respectively. The results also reported that in the given concentration and airflow, production of CO2 in TiO2-AC reactor was higher than TiO2.

    Conclusion

    Results of the present study indicated that combining titanium dioxide with activated carbon adsorbent is a useful method in removing toluene gas from air under UV and combining photocatalytic elimination with adsorption process by activated carbon led to increased removal efficiency. Self-cleaning photocatalyst had high efficiency in the present study and the use of photocatalytic-adsorption bed can as a suitable method with high removal efficiency causing adsorption and treatment of the pollutants. In other word, combination Activated carbon with Titanium dioxide improved the functionality of activity of photocatalytic oxidation through promoting adsorption sites and increasing residence time of the pollutant in the bed.Results also indicated that removal efficiency was influenced by initial concentration of toluene and retention time of pollutants on the bed and optimizing these parameters may lead to maximum efficiency in photocatalytic setups. The combined catalysts with surface adsorbents led to improved decomposition efficiency based on photocatalytic decomposition and it is likely that the improvement is mostly the result of increasing adsorption sites compared to limited adsorption sites found in the photocatalyst. On the other hand, with more adsorption site, the pollutant had much more time to have contact with photocatalysts and consequently improved circumstances for surface oxidation reactions Keywords: Indoor Air Quality (IAQ), Titanium Dioxide (TiO2), Activated Carbon, Volatile Organic Compounds, Toluene, Photocatalytic Oxidation, Adsorption-Photocatalytic bed.

    Keywords: Indoor Air Quality (IAQ), Titanium Dioxide (TiO2), Activated Carbon, Volatile Organic Compounds, Toluene, Photo catalytic Oxidation, Adsorption-Photo catalytic bed
  • Behzad Fouladi*, Abbas Mohammadi, Ali Rastin, Kabize Ahmadi, Faramarz Ghargozlu Pages 88-97
    Background and aims

    Workplaces with poor lighting conditions often created occupational accidents or illness. This occurs because light cause visual and nonvisual effects on numerous physiological variables, such as the human sleep-wake cycle and cognitive performance. Indoor lighting conditions, as one aspect of the work environment, Influence on occupant’s mood, well-being, task performance and work engagement. Greater satisfaction in case of lighting conditions at workplace is usually depending on higher work plane lighting, lighting uniformity, absence of glare, light directionality (ratio of horizontal and vertical illumination), as well as the presence of a window. Thus, selecting suitable lighting system is an important part of increasing productivity in the office work plan. Although Fluorescent lighting is a conventional system in a range of industrial and domestic applications, but newer technologies such as light-emitting diodes (LED) have begun to attract as one of the most promising candidates for sources of general illumination in the near future. This is due to variety of advantages such as lower power consumption, longer usable lifetime, greater eco-friendliness due to do not contain mercury and easier processing due to their small size and adaptable shape. Due to significant growth of the LED technology and the possibility of their replacement with Fluorescent technology, it is important to evaluate the effects of these modern lighting options on worker performance. In fact, lighting can cause acute emotional, behavioral, and cognitive problems. These effects of light may be dependent on parameters such as intensity, power, and type of light source. The aim of this study was to compare the effect of fluorescent and LED light sources on the alertness, cognitive performance and visual comfort level among student in a laboratory environment.

    Methods

    Twenty eight participants (19 to 35 years of age) were recruited to participate in this study. All participants were screened for health problems, especially about neurological diseases, mental and visual disorders. Test environment is a room with dimensions of approximately 2 x 3 x 3 meters and without natural light (with no window). All lighting sources were installed on the ceiling of room test. 4 fluorescent tube lamp on the right side and 9 white LED lamps on the left side of room were installed. Under each of lighting source a table and chair to carry out the defined tasks were placed. Turn on/off button each of lighting source also is separate. This characteristic is extracted from the booklet of lamp Manufacturers. For each participant in the study, a series of tasks and tests to measure the level of alertness, cognitive performance and visual comfort was designed. EEG method was used to measure the level of alertness. For this purpose, NeXus-4 device was used for data collection. The NeXus-4 is a small and high-end biofeedback and neuro-feedback system which is totally suitable for professional grade physiological monitoring, and clinical applications. Data processing, digital Signal filtering, Trends report and statistical analysis is done by the Bio Trace software that is compatible with the device. Using this device, signals the brain activity of the participants were recorded. Nexus-4 takes advantage of active Noise Cancellation technology, where artifacts and external interference were reduced and provides high-quality EEG signals. Electrodes were placed on subjects’ scalps according to the International 10-20 system. According to the instructions of device, reference electrode on the left ear was placed. Ground electrode (white) on the right ear and red electrode on the point Cz of the head (located in the occipital region) was placed. Gamma frequency range 35-45 Hz, beta frequency range 13-21 Hz, alpha frequency range 8-12 Hz, was set on the device.  One goal of the study was to evaluate the effect of two different lighting sources (LED and fluorescent) on participant’s performance during a computer-based visual task. For this purpose, “Freiburg Visual Acuity & Contrast Test” (FrACT) was used. In this method, participants by viewing the computer screen determine the orientation of ring and give the appropriate response via the computer keyboard as soon as possible. Then for each step, a performance indicator for contrast and visual acuity test were determined as follow calculation: (Total number of correct responses / Total duration of step). In following, the contrast and visual acuity threshold was determined by the software itself for each participant. For carry out this task, an experiment was used that proposed in 1999 by the Courret. Just as computer-based tasks, Landolt rings were used for paper-based tasks.  The participants of this study received a sheet of white paper on which 96 Landolt ring was printed in grey (very low contrast), and they were asked to determine as quickly as possible the correct orientations of all the 96 rings by writing down the number counted each ring in the bottom of the page. Then, the number of errors was counted as a performance of paper-based tasks for two lighting environments. In addition, participants in this study had to express our visual comfort under two lighting sources. For this purpose, Office Lighting Survey (OLS) was used to evaluation the satisfaction of participants during each lighting sources. OLS is a simple, valid, reliable questionnaire-based assessment method for human satisfaction regarding office lighting. This questionnaire was presented by Elkland and Boyce in 1996. Participants in this study were asked to express their satisfaction or dissatisfaction of existing lighting sources with  each statement by using the 4-point Likert scale with no neutral choice (yes, rather yes, rather no, no).

    Result

    the results obtained during the computer-based tasks under two different lighting sources. For both fluorescent and LED lighting source, average performance efficiency is 0.66 and 0.64, respectively. There was no statistically significant difference between the two different lighting conditions (p=0.13). A comparison of the average contrast threshold obtained during the contrast test between the two sources of lighting. For both fluorescent and LED lighting source, average contrast tests obtained 0.52 and 0.45, respectively.  Again no statistically significant difference was observed between the two different lighting conditions (p=0.356). The results obtained during the paper-based tasks under two different lighting sources. The average of error in the identification of ring’s orientation is more in LED lighting source than fluorescent lighting source. There was no statistically significant difference between the two different lighting conditions in orientations of up (P = 0.074), down (P = 0.896), right (P = 0.713) and left (P = 0.246). Also, the average number of error for all Landolt-ring orientations under two lighting sources. On average, under the fluorescent lighting, 3.93 rings and under the LED lighting, 4.93 rings were incorrectly identified by the participants. Comparing the average error in orientations of Landolt-ring show was no statistically significant difference between the two lighting conditions (p=0.1≥0.05). The results of subjective visual comfort represented that the maximum difference between tow lighting source in the second question (Q2) (In general, the lighting in this office is comfortable), Q3 (This color of light allows me to carry out the different tasks) and Q4 (My skin looks natural under the light.) were observed. Also statistical analysis showed a significant difference to these questions Where p-value was equal to Q2 (0.001), Q3 (0.011) and Q4 (0.003). The results of questionnaire analysis (subjective preferences and visual comfort) showed that the fluorescent lighting (66.83 points) was most preferred by the participants than LED lighting (51.83 points). There were statistically significant difference among the two lighting source where fluorescent light was significantly better preferred to LED light (p = 0.002). In terms of visual comfort, fluorescent light (68.1 points) was most comfortable than LED light (67.33 points) but there was no statistically significant difference between two lighting conditions (p = 0.6). Electroencephalograms mean relative power for alpha, beta and gamma frequency band at the CZ electrode were recorded. The mean relative power of frequency bands of all participants for LED lighting condition is more than fluorescent lighting condition. Also, in between three frequency band, alpha and beta bands were the biggest values. For gamma frequency band, T-test revealed that each lighting condition showed no statistically significant difference on alertness level of participant (p=0.24). Statistical analysis for alpha and beta frequency band showed a significant difference between two lighting source.

    Conclusion

    In general, participants in this study reported that they most comfortable in fluorescent lighting conditions and more preferred this lighting source than LED lighting source. Performance of participants in paper-based task was significantly better under the fluorescent lighting condition than under the LED lighting condition. Under fluorescent lighting conditions, participants on average 3.93 rings and under LED lighting condition 4.93 Ring incorrectly identified. This results show that Participants to carry out paper-based tasks under the LED lighting sources more likely commit to make errors. Even though these errors were not statistically significant, it can be inferred that the light source (fluorescent or LED) have a little effect on the carry out of paper-based tasks and the most important cause of error during cognitive tasks is the brightness level and individual variables such as age. The participant’s performance in the computer-based tasks under fluorescent lighting source was better than LED lighting source. Visual acuity and contrast threshold of participant’s under fluorescent lighting conditions is better than LED lighting conditions. But no statistically significant difference was observed. In other words, we can conclude that participants while performing computer tasks did not show better or worse performance under both lighting source. These conclusions indicate that the light source (fluorescent or LED) does have little impact on computer-based tasks. Also similarly studies carried out by Linhart et al. (2011) and Shamsul et al. (2013) that don’t show significant difference in visual acuity and contrast thresholds users and this may indicate that the FrACT test is not appropriate for this particular field. During the assessment of subjective visual comfort, the first question (I like the lighting in this office) scored satisfaction of 75% for fluorescent lighting source and 61% for LED lighting source. The second question (In general, the lighting in this office is comfortable.) scored satisfaction of 74% for fluorescent lighting source and 52% for LED lighting source and there were statistically significant difference among the two lighting source for this question. As a matter of fact, only the differences in statements of Q2, Q3 and Q4 are statistically significant that’s shows participants in this study subjectively most comfortable in fluorescent lighting conditions than LED lighting source. However, the absence of significance in other cases may be due to the small number of study participants. As regards the questions of visual comfort questionnaire was designed based on two dimension preference and visual comfort, the results of comparison these two dimension show that fluorescent lighting to LED lighting is the most preferred and the results are statistically significant. Comparison the visual comfort result of the participants also showed that fluorescent lighting to LED lighting is the most comfortable sources but this was not statistically significant. The results suggest that 50% of the participants prefer fluorescent light to LED light for carry out cognitive tasks. In this study, we analyzed the EEG spectral power measured on the participants in order to compare the effects of LED and fluorescent lighting on alertness. In our study, results showed that the EEG power for alpha, beta and gamma frequency bands for LED lighting are more than fluorescent lighting. This increase in the range of alpha and beta frequency bands was significant. This indicates that LED lighting could disturb human alertness in compared with fluorescent lighting. Hawes et al. recently shown that, the LED lighting in compare with the fluorescent lighting may have positive effects on perception, cognition and affective state. However, our results proved the opposite of this report. In contrast, our results indicate that the LED lighting have significantly effect on the alertness, cognitive performance and visual comfort level. As we examined only some short-term effects of LED lighting in a small community and long-term effect should be studied in the future.

    Keywords: lighting, alertness level, EEG, Fluorescent, LED