فهرست مطالب

محیط شناسی - سال چهل و پنجم شماره 4 (پیاپی 92، زمستان 1398)
  • سال چهل و پنجم شماره 4 (پیاپی 92، زمستان 1398)
  • تاریخ انتشار: 1398/12/01
  • تعداد عناوین: 10
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  • مریم جعفری، محسن تابان، محسن صفاری پور* صفحات 589-603

    تغییرات اقلیمی و گرم شدن زمین توجه به مسایل حرارتی در محیط شهری ایجاب می کند. یکی از راهکارهای برخورد با این موضوع، توجه به آسایش حرارتی و شناخت مولفه های تاثیرگذار بر آسایش حرارتی در محیط بیرونی است. در این تحقیق سعی شده است تا آسایش حرارتی خیابان چمران شهر کرمانشاه واقع در غرب ایران مورد سنجش قرار گیرد. در این مطالعه، برای ارزیابی آسایش حرارتی از برداشت میدانی استفاده شده است. پارامترهای اقلیمی به صورت میدانی اندازه گیری شده اند. نتایج برداشت های میدانی به همراه مدل سازی وضعیت حرارتی در نرم افزار ENVI MET موردمطالعه قرار گرفت. در مطالعه موردی، برای ارزیابی و اندازه گیری میزان تغییر محصوریت فضا، چندین نقطه برای اندازه گیری محدوده های سنجش و بررسی پارامترهای حرارتی در فضای باز و رفتارهای انسانی انتخاب شد. با توجه به مطالعه انجام شده محدوده آسایش حرارتی در محدوده موردمطالعه در دمای بین 16 تا 19 درجه قرار دارد که به دلیل نرخ فعالیت بالا رخ داده است. . بررسی نتایج میدانی و مدل سازی وضعیت حرارتی با استفاده از نرم افزار ENVI MET نشان داد که برای طراحی یک فضای شهری پایدار و مناسب در این اقلیم با مداخله در فضا ، می توان در منطقه آسایش تغییر ایجاد کرد.

    کلیدواژگان: آسایش حرارتی، فضای باز، PMV، کرمانشاه، ENVI-met
  • مرتضی تهامی پور زرندی*، عبدالرحمن بی ترس صفحات 605-623
    زیربنا و قدم اولیه هر حرکتی در راستای درک اهمیت یک اکوسیستم جنگلی، ارزشگذاری و برآورد ارزش پولی خدمات و منافع آن است. در این پژوهش ارزش اقتصادی خدمات اکوسیستم جنگل پردانان شهرستان پیرانشهر، با استفاده از دو روش هزینه سفر انفرادی و ارزشگذاری مشروط برآوردشده است. داده-های پژوهش از طریق مطالعات میدانی و توزیع 400 پرسشنامه در سطح شهرستان پیرانشهر و منطقه جنگلی پردانان در بهار و تابستان سال 1397 به دست آمده است. نتایج پژوهش نشان داد که در روش هزینه سفر، مازاد مصرف کننده فردی به ازای هر بازدید به طور متوسط حدود 53 هزار تومان و کل مازاد مصرف کنندگان تحت سناریوهای مختلف در بازه حدود 4 الی 60 میلیارد تومان می باشد. همچنین در روش ارزشگذاری مشروط، تمایل به پرداخت سالیانه هر پاسخ دهنده برای حفاظت از کارکردهای پردانان حدود 68 هزار تومان و ارزش کل سالیانه این جنگل در سناریوهای گوناگون در دامنه 4/1 الی 27/21 میلیارد تومان برآورد گردید. این برآوردها حاکی از ارزش بالای کارکردهای جنگل پردانان برای مردم منطقه و گردشگران مختلف است و پیشنهاد می شود این موارد در برنامه ریزی برای توسعه و تامین مالی و جلب مشارکت بخش خصوصی در حفظ و احیای اکوسیستم مدنظر قرار گیرد.
    کلیدواژگان: مازاد مصرف کننده، هزینه سفر، تمایل به پرداخت، ارزشگذاری مشروط، جنگل پردانان
  • احمد سلطانی ذوقی، افسانه سراج الدین، احمد فتاحی اردکانی* صفحات 625-643
    بهبود کیفیت محیط زیست به عنوان معیاری برای بهبود کیفیت زندگی، عاملی اساسی در توجه به مناطق حفاظت شده است. مدیریت مناطق حفاظت شده نیازمند رویکردی جامع در فرآیند تصمیمگیری می باشد. مطالعه حاضر در بهار1397 و با تکیه بر نظر کارشناسان، ساکنین و گردشگران مناطق حفاظت شده ی استان همدان صورت پذیرفته است. اطلاعات جمع آوری شده از 400 پرسشنامه ی توزیعی در منطقه با ترکیبی از مدل های SWOT و روش تحلیل شبکه ای ANP، تجزیه و تحلیل شده است. روش تحلیل شبکه ای به صورت یک روش تصمیم گیری چهار مرحله ای مورد استفاده قرار گرفت. با استفاده از روش ماتریس SWOT استراتژی های بهینه با تاکید بر نقاط ضعف قوت فرصت ها و تهدیدها تعیین و با استفاده از روش تحلیل شبکه ای نسبت به رتبه بندی این استراتژی ها اقدام شده است. چهار استراتژی نهایی توسط کارشناسان تعیین شده و با استفاده از نظرات پرسش شوندگان رتبه بندی نهایی صورت گرفت. استراتژی توسعه پایدار و استراتژی حفاظت سبز با ضرایب 0/332 و 0/288 به عنوان استراتژی های غالب در مناطق مورد مطالعه انتخاب گردیدند. نتایج از اصلاح رویکرد فعلی حمایت کرده و انتظار میرود نتایج مطالعه در سیاست گذاری ها، در منطقه ی مورد مطالعه مورد توجه قرار گیرد. این مطالعه می تواند به عنوان مبنایی برای سایر مطالعات در زمینه ارزیابی استراتژی های منطقه ای در مناطق مختلف کشور استفاده شود.
    کلیدواژگان: ماتریس SWOT، تحلیل شبکه ای ANP، توسعه پایدار، حفاظت سبز، همدان
  • الهام قهساره اردستانی*، مژده نافیان، محسن بهمنی صفحات 645-661
    درختان فضای سبز شهری به رغم ارایه طیف وسیعی از منافع زیست محیطی، زیباشناختی، اجتماعی، فیزیولوژیکی و اقتصادی می توانند باعث خطرات جانی و مالی برای شهروندان شوند. اهداف این تحقیق برآورد احتمال خطر سقوط درختان نارون و مدل سازی آن از طریق شبکه عصبی و رگرسیون لجستیک است، بدین ترتیب 129 اصله درخت نارون در خیابان شریعتی شهرکرد بررسی شدند. برای این منظور، متغیرهای قطر و ارتفاع درخت، شاخه و سرشاخه های خشکیده، شکاف یا ترک، وضعیت و ضعف ساختاری، مشکلات ریشه و پوسیدگی تنه و شاخه به عنوان متغیرهای مستقل و طبقه شدت خطرآفرینی درختان نارون به عنوان متغیرهای وابسته در مدل شبکه عصبی مصنوعی و رگرسیون لجستیک استفاده شدند. در این پژوهش از شبکه پرسپترون چند لایه با 5 نورون در لایه ورودی، یک لایه پنهان با 20 نورون و یک نورون در لایه خروجی استفاده شد. نتایج نشان داد که رگرسیون لجستیک نتوانست بین متغیرهای مستقل و طبقه شدت خطرآفرینی درختان نارون برازش خوبی را انجام دهد. در صورتی که شبکه عصبی قادر بود مدلی مناسب را برازش دهد. به طور کلی شبکه عصبی با کارایی مناسب و بالا در مقایسه با روش رگرسیون لجستیک، برای پیش بینی خطر سقوط درختان نارون، مناسب تر بوده است.
    کلیدواژگان: معیارهای تشخیصی خطرآفرینی، تجزیه و تحلیل مولفه های اصلی، ضریب تبیین، منحنی مشخصه عملکرد، شاخص کاپا
  • مریم رباطی*، مریم حسینی، نبی الله منصوری صفحات 663-678

    صنعت سیمان بزرگ ترین منتشرکننده دی اکسیدکربن دربخش صنعت می باشد.هدف از انجام این تحقیق معرفی روش TES_LCA درکاربردخدمات اکوسیستمی درارزیابی چرخه حیات کارخانه سیمان فرازفیروزکوه است که برای انجام این کار از نرم افزارSima Pro ورژن 9 استفاده شده است وتعداد 11شاخص زیست محیطی از جمله تغییرات آب وهوایی و... تحت4 سناریو کلی که عبارت اند از: سناریو اول: تولید سیمان پورتلندبدون در نظر گرفتن خدمات اکوسیستمی منطقه، سناریو دوم: تولید سیمان پوزولان بدون در نظرگرفتن خدمات اکوسیستمی منطقه، سناریوسوم :تولید سیمان پورتلند با درنظر گرفتن خدمات اکو سیستمی منطقه،سناریو چهارم: تولید سیمان پوزولان با درنظرگرفتن خدمات اکوسیستمی منطقه،موردپردازش و بررسی قرارگرفتندواین نتیجه به دست آمدکه اثرهای مسمومیت انسان سرطانی و غیرسرطانی ومسمومیت آب های شیرین وگرمایش کره زمین به ترتیب نمودبیشتری نسبت به سایراثرات زیست محیطی دارند. همچنین مشخص شد که استفاده از خدمات اکوسیستمی در فرآیند ارزیابی چرخه حیات باعث دقیق تر شدن نتایج ارزیابی چرخه حیات شده و مقداری از اثرات زیست محیطی را برای نتایج ارزیابی چرخه حیات کارخانه سیمان فراز فیروزکوه کاهش می دهد وکارخانه سیمان فراز فیروزکوه با فرآیند تولید سیمان پوزولان که در ماده اصلی آن از خاستر بادی استفاده شده است، اثرات زیست محیطی کمتری را نسبت به تولید سیمان پورتلند دارد.

    کلیدواژگان: خدمات اکوسیستمی، LCA، TES، صنعت سیمان، نرم افزار Sima Pro
  • فاطمه عادلی ساردو، حمید رضا جعفری*، بهرام ملک محمدی، عبدالرضا کرباسی صفحات 679-691

    در این تحقیق جهت بررسی وضعیت منابع آب بخش کشاورزی دشت جیرفت تغییرات عمق آب های زیرزمینی در یک دوره ی ده ساله با استفاده ازروش های زمین آمار در نرم افزار Arc Gis10.5 مورد بررسی قرار می گیرد. به منظور تعیین نقش کاربری کشاورزی در کاهش سطح آب های زیرزمینی به بررسی عملکرد محصولات کشاورزی تولیدی پرداخته و مقدار آب مجازی برای محصولات شاخص محاسبه می گردد. جهت تعیین نقش خشکسالی در کاهش سطح آب شاخص های SPI, RAI, DI,ZSI, CZI, MCZI با بهره از نرم افزار RDIT مورد بررسی قرار می گیرد. نتایج افت یک متری سطح آب های زیرزمینی در هر سال را نشان می دهد. نتایج مربوط به آب مجازی ، تولید و صادرات محصولات کشاورزی آب بر با ارزش اقتصادی پایین را ارایه می دهد. شاخص های خشکسالی فراگیرترین خشکسالی شدید رامربوط به سال های 1379، 1383 ، 1389و 1390 می داند. در سال های دیگر خشکسالی با سطح متوسط ولی مکرر وجود دارد که ناشی از ماهیت خشک و بارندگی کم در منطقه می باشد ودر مواردی نادر با حالتی غیر از خشکسالی روبرو بوده است. با وجود بحران کم آبی، به طور خاص در مناطق خشک و کویری و با مصرف درصد بالایی از منابع آبی در بخش کشاورزی ، لازم است که محصولات تولیدی دارای مزایای نسبی، ارزش افزوده و کمترین نیاز به آب باشد.

    کلیدواژگان: تراز آب های زیرزمینی، آب مجازی، خشکسالی هواشناسی، دشت جیرفت
  • لیلا کوکبی* صفحات 693-709

    در سکونتگاه های شهری و روستایی، انسان ضمن برقراری روابط فرهنگی-اجتماعی با جامعه، با محیط پیرامون خود نیز در تعامل است و این تعاملات طی زمان تغییر می یابد. تحولات روستایی درحال وقوع در ایران، در بلندمدت منظر روستایی را دستخوش دگرگونی می سازد؛ از آنجا که کارکردهای منظر روستایی درگذر زمان متنوع تر شده، امروزه در ارزیابی آن علاوه بر کیفیت های بصری، ابعاد محیط زیستی و ارزش های فرهنگی نیز مورد توجه قرار می گیرند. واکاوی واکنش های ایجادشده درپی تاثیرگذاری عوامل پیش برنده در زمینه روستا، راهگشای درک بنیان های منظر پایدار روستایی است. روش پژوهش کیفی بوده و هدف آن یافتن زمینه های وقوع، فرآیندها و واکنش های بروز یافته است که منجر به شکل گیری اجزا و عناصر منظر روستایی و پایداری آن شده اند. با مراجعه به عرصه زندگی واقعی و بهره گیری از نظریه زمینه ای و مشاهده مشارکتی، فرآیندها، واکنش ذی اثران و پیامدهای موثر در ایجاد منظر روستایی مرحله به مرحله تحلیل و تبیین شده است. نتایج نشان می دهد پایداری محیطی فورگ بر ویژگی های بنیادین منظر روستایی از جمله: "برخاستن الگوی معماری بنا از فرم زمین و اقلیم"، "غلبه باورها و عقاید بر شکل گیری منظر روستایی"، "تجانس و همگنی بافت روستا با زمینه"، "شکل گیری منظر بر پایه امنیت" و "یکدستی و عدم تنوع منظر کشاورزی" بنا شده است.

    کلیدواژگان: منظرپایدار روستایی، نشانگرها، نظریه زمینه ای، مشاهده مشارکتی، روستای تاریخی فورگ
  • فاطمه جان پور، علی ترابیان*، همایون احمد پناهی، مجید بغدادی صفحات 711-724
    در این تحقیق جهت گندزدایی و شیرین سازی آب، نانوکامپوزیت گرافن اکساید- دندریمر- نقره برای پوشش الکترودهای دستگاه یون زدایی خازنی سنتز شد. خصوصیات نانوذرات سنتز شده توسط آنالیز FTIR، TGA و FESEM مشخص شد. تاثیر پارامترهایی نظیر شوری به وسیله محلول آب نمک با میزان شوری 1000 تا 20000 میلی گرم بر لیتر، میزان کلی فرم ورودی 500 تا 100000 ام پی ان1 (MPN) و تاثیر زمان ماند در مدت زمان 5 تا 120 دقیقه مورد ارزیابی قرار گرفت. این سیستم قابلیت حذف یونها از آبی با میزان شوری 20000 میلی گرم در لیتر با راندمان 98% را در مدت زمان 90 دقیقه و قابلیت حذف 9/99% از 1000 ام پی ان کلی فرم ورودی را در مدت زمان 30 دقیقه، 10000 ام پی ان را در مدت 60 دقیقه داشتند. ولتاژ کاربردی این سیستم 2 ولت می باشد. این سیستم قابلیت جذب بالا در مرحله حذف یون ها و واجذب بالا در مرحله شستشوی الکترودها در مدت زمان چند دقیقه دارد، بنابراین می تواند به صورت پیوسته کار کند. به دلیل پیوند قوی دندریمر و گرافن اکساید و کمپلکس میان نانوذرات نقره و دندریمر احتمال انتشار نانوذرات نقره در آب وجود ندارد. بنابراین این سیستم یک راهکار مناسب و ایمن برای استفاده از نانوذرات نقره در تصفیه آب به شمار می رود.
    کلیدواژگان: یون زدایی خازنی، گندزدایی، نانوذرات نقره، دندریمر
  • احمد حقگوی، عزیر عابسی*، علی رحمانی فیروزجاهی صفحات 725-740
    در دنیای مدرن انسان بطور متوسط حدود 90-70 درصد اوقات خود را در محیط های بسته می گذراند و بیشتر فعالیت های افراد در داخل چنین فضاهایی صورت می گیرد. وجود انواع آلاینده ها با غلظت بالا در فضای تنفسی انسان در خانه نقش تاثیرگذاری بر سلامت ساکنین دارد. بنابراین طراحی این فضاها بایستی به نحوی انجام گیرد که تضمین کننده تازگی و کیفیت مطلوب هوا در داخل ساختمان باشد. در این پژوهش، دینامیک انتقال و پخش پلوم آلودگی (گاز مونوکسید کربن) از یک منبع نقطه ای در محیط های ساکن داخل ساختمان مورد مطالعه قرار گرفته است. پخش آلودگی در محیط متاثر از تاثیر توامان نیروهای شناوری و مومنتوم و آشفتگی های ناشی از آن است. در مدلسازی انتشار گاز در هوای داخل ساختمان، به دلیل عدد ماخ پایین و تغییرات ناچیز فشار جریان، سیال را می توان تراکم ناپذیر فرض کرد. از اینرو در این تحقیق آزمایشات در محیط آبی و با استفاده از تکنیک لیزری آشکارسازی فلورسنت انجام گرفته است. با شبیه سازی آزمایشگاهی فرآیند پخشیدگی جریان در محیط در نهایت مقادیر بدست آمده با مقادیر مجاز مونوکسیدکربن در محیط مقایسه گردید. در نتیجه ضرورت استفاده از تهویه مکانیکی به منظور ارتقای کیفیت هوای محیط مورد تاکید قرار گرفت.
    کلیدواژگان: پلوم آلودگی، انتقال، انتشار، شبیه سازی آزمایشگاهی، Lif
  • مریم ایزانلو، مهدی فرزادکیا، احمد جنیدی، علی اسرافیلی*، حسین کریمی، سحر فرخی صفحات 741-753
    کادمیوم به علت داشتن اثرات سمی شدید بر روی ارگان های بدن انسان به عنوان یک ماده سرطانزا شناخته شده است. به طوریکه که مصرف دراز مدت آن معمولا منجر به سرطان ریه، استیومالاسی،پرفشاری خون،نقص های مادرزادی،جهش زایی، کمبود آهن، کلسیم، پروتیین و ویتامینD می شود. بر این اساس مطالعه با هدف جذب کادمیوم از محلول های آبی توسط نانوذرات مزوپوز اکسیدآهن سنتز شده به روش هم رسوبی انجام گرفت.دراین پژوهش، نانوذرات مزوپوز اکسیدآهن به روش همرسوبی سنتز شد و سپس به منظور پوشش دهی آن از ماده تترااتیل اورتوسیلیکات استفاده گردید.جهت بررسی مشخصات جاذب ازدستگاه های اشعه پراش پرتو ایکس(XRD)،طیف سنج مادون قرمز(FT-IR)،میکروسکوپ الکترونی عبوری(TEM)و روبشی(SEM) استفاده گردید.آزمایشات جذب شامل تعیین pH بهینه و زمان تماس دربازه ی60-10 دقیقه انجام گرفت.درنهایت ارزیابی سینتیکی، ایزوترمی و ترمودینامیکی حذف کادمیوم نیز بررسی شد. نتایج نشان داد که نانوذره Fe3O4@SiO2دارای اندازه تقریبیnm 15می باشد. PH برابر 5 و زمان تماس30 دقیقه به عنوان شرایط بهینه جذب کادمیوم انتخاب گردید.براساس نتایج،جذب سطحی کادمیوم بر روی نانوذره Fe3O4@SiO2 ازمدل سینتیک شبه درجه دوم و ایزوترم دمایی لانگمویر پیروی کرده است.بعلاوه پارامترهای ترمودینامیکی نشان داد که فرآیند جذب کادمیوم بر روی جاذب خودبه خودی و گرماگیر است.
    کلیدواژگان: جذب سطحی، کادمیوم، سینتیک، ایزوترم، ترمودینامیک
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  • Maryam Jafari, Mohsen Taban, Mohsen Saffaripour * Pages 589-603

    Introduction In Iran, there has not been much research and study on the effects of macro-scale climatic factors (especially in the cold climate and cold season); only a few studies on the mental senses of people in urban open spaces have been used in this climate. Is. Therefore, in this paper, we try to investigate the factors affecting cold weather in the cold season in urban streets by examining the thermal comfort index (PMV) and introducing ways to balance the comfort with physical intervention. Methodology This study is carried out for typical winter conditions in Chamran Street in Kermanshah (34.19 N latitude and 47.7 E) located in the Iran. The climate of this city is cold and mountainous. In this article, February 11 was considered as one of the coldest days of the year (one of the most critical days of the year) to study. The case study has width of 40 meters with a East-West orientation. The height of buildings is between 3 and 39 meters. The ground floor use of this street is mainly commercial and the major materials used in the facade of the buildings, stone and brick, on the floor of the mosaic and concrete Street and in the middle street reflection are also stones. The shadow projection and the Calendar of Climate Needs for Kermanshah City show that there is a need for radiation in the coldest days of the year (from mid-October to March) . Therefore, providing sunlight is very necessary. In April, you will need both radiation and shadows. In the months of May to September, shade is needed. Therefore, urban spaces should be designed in a way that meets the needs of people in all seasons.. Several tools were used to collect climatic parameters. In this study, we used an anemometer to measure the wind, and to measure the temperature humidity, humidity and spherical temperature from a multi-function data logger. (Table 1). In order to measure physical parameters, the instruments were placed at a height of 1.5 m above the ground plane on a stack in the areas under study. The study area was selected according to the variation in the enclosure of several points to investigate and measure the climate parameters. All points were monitored at 5-minute intervals on February 11. . Multi-function data logger measurements with 30 second intervals were automatically recorded from 9-17. Other measurements were done manually due to lack of data logger. This interval is chosen because the greatest number of people in the urban space occurs at this interval In this research, the model of the standard Ashrae 55 is used. This climate model is used to calculate and simulate climate variables in urban space with regular grids accuracy of 0.5 to 10 meters. Discussion Observations show that PMV has changed tremendous in comparison to the existent situation, and comfort zone have changed over the course of time, but Tmrt has not changed much. In the intervention, this article did not change much in the mean radiant temperature, but the thermal comfort index has changed considerably. As a result of decreasing a building with two feedback 3-meter and 4 meters in height, the PMV at 9 o'clock from a relatively cold zone to cold zone and has reached to comfortable zone at 10-12 o'clock. Between 13 and 15, the most change is observed, with the PMV zone changing from very cold to cool and relatively cold. Therefore, based on the studies conducted on the basis of studies carried out, in the temperature at 45° to 56°, the street of Chamran is in the comfort zone. Therefore, the design of the spaces should be such as to obtain the highest amount of solar radiation , in order to improve the comfort of the spaces. Therefore, it is suggested that in the future development plan of the city, it should be proposed in the South Front building, to feedback for buildings above 24 meters Because the best way to improve the comfort of Chamran Street in winter is having a 30-32° shadow angle, which PMV will have the best of situation.. Conclusions Recent studies have shown that the closure of urban canyons affect on the microclimate at the street level. This study, Thermal Comfort in an Urban Street Cold Region Calculated by using physics parameters and evaluation personal variables . This study also had the goal to Calculated Thermal Comfort in an Urban Street Cold Region by software was able to evaluated outdoor thermal perception, One of the output data of ENVI-met is the Predicted Mean Vote (PMV), a thermal comfort index based on a 7-point scale ranging from -3 to +3. This study has examined techniques in responding sufficiently to the urban geometry characteristics, such as H/W ratio and SVF . So, by analyzing field survey and existent and proposed simulation the following results were obtained: 1- To determine the effect of solar radiation on the amount of thermal comfort, the relationship between SVF and PMV is investigated in different locations that are analyzed. In the study area, sections have more opening (higher SVFs) have more potential for solar access in winter , and this improves the comfort of people 2- Based on the simulation carried out on the model, the desired intervention is affected by many changes in the climate and the thermal comfort of the outdoor space. The mean radiant temperature under the influence of some components is significant changes, including the vegetation added to The site is designed to reduce the radiant temperature, which reduces the comfort of people during cold weather. So, reducing the height of high-rise buildings on the street can have an impact on improving the comfort of the street.

    Keywords: Thermal Comfort, open space, PMV, Kermanshah, ENVI-met
  • Morteza Tahami Pour Zarandi *, Abdolrahman Bitars Pages 605-623
    Introduction Evaluation is the first step in designating the importance of environmental districts and emphasizing their economic aspect. In this research, the economic value of Perdanan forest in Piranshahr city, the most significant functions of which are in the fields of aesthetic, entertainment, climate adjustment, wildlife habitat, protection of plant species, and flowage control, is estimated through two current methods of Contingent Valuation Method and Individual Travel Cost Method. The goal of this evaluation is designating the importance of the protective and recreational functions of Perdanan forest and measuring the Revealed and Expressed Willingness to Pay of the individuals and their effective factors in order to secure the functions of this jungle. Contingent valuation Method (CVM) is always facing with the probability that the individual pays less than his willed amount, due to the conjecture that proclaiming a specific payment might cause the actuality of payment, and as a result, a lower expected value might be estimated. Individual Travel Cost Method (ITCM) concentrates on the recreational use and neglects the protective and other functions, however, it has the advantage of using the real prices over CVM. In this method, no longer does the individual proclaim his Willingness to Pay (WTP), yet by utilizing a set of technics, his WTP is depicted by calculating the replacing prices. Consequently, employing and comparing both of the noted methods would result in more comprehensive outcomes and also reveal the differences of human behaviors in different markets. Materials & Discussion The data of the research is gathered by distributing and completing 400 surveys throughout Piranshahr city and Perdanan districts during 1397/2018 spring and summer, which is an appropriate time for tourism. After further scrutiny, 24 surveys were omitted due to the outliers, therefore, the data analysis has been done with 376 surveys. With the resultant information, Logit Model, for reaching WTP function, and Zero-Truncated Negative Binomial Model (ZTNB), for reaching the Travel Demand function, has been estimated to obtain the economic value of Perdanan and the yearly value of the forest has been designated in different scenarios. The resultant outcome of Logit Model shows that the variables of gender, marital status, household size, monthly income, and the yearly amount of visits to Perdanan are not statistically significant, yet the symbol of estimated coefficients shows that females, married people, those with larger households, with higher monthly income, and those who yearly travel more recurrently to Perdanan have had more WTP to secure the functions of Perdanan. Also, the most important explanatory variable in the model, meaning the bid variable has become significant and per 1000 Tomans of increasing the bid price, the probability of average acceptance lowers approximately 1.6 percent. The variables of education level, NGO membership, and locality are also significant with 99 percent certainty so that it is expectable that with the increase of one unit of education level and change of status from non-NGO member to NGO member, the average probability of acceptance increases 8.1% and 31% and for each unit of change of status from non-local to local, the average probability of acceptance decreases 23%. Therefore, the most effective factors on the payment by individuals to secure functions of Perdanan are NGO membership, locality, education lever, and the suggested fee. Moreover, WTP per person per year in order to secure the functions of Perdanan is estimated around 68000 Tomans and the total yearly economic value of Perdanan under different scenarios is estimated in a range between 1.4 billion to 21.27 billion Tomans. The results of ZTNB model are also implying that the variables of household size, marital status, and gender are not statistically significant but the symbol of estimated coefficients of these variables suggests that people with larger household, married status, and male gender have had more recurrent travels to Perdanan. Nevertheless, the most important factor discussed in ITCM, i.e. the variable of travel costs, is statistically significant on the level of 99% certainty and per 1000 Tomans increase in the travel costs, the average probability of visiting Perdanan will decrease approximately 0.37%. Furthermore, the variables of locality, monthly income, and age are significant with a certainty of more than 99% and with one unit of change of status from non-local to local, the probability of the individual visit to Perdanan increases approximately 5.2% and with the increase of one unit in the individual age and 1000 Tomans monthly income, the probability of visiting Perdanan respectively decreases by 0.3% and increases 0.0074%. The most important factors in individual demand from Perdanan recreational site are, then, locality, travel costs, age, and individual monthly income. Using the estimated coefficients, individual consumer surplus per Visit is estimated at about 53000 Tomans and total consumer surplus in different scenarios is estimated in the range from 4 billion to 60.47 billion Tomans. The resultant outcomes of both methods proved Perdanan forest peculiarly important for residents of Piranshahr and other visitors. Therefore, the authorities and the relevant organizations can utilize these outcomes in financing and efficient decision-making and possibly prioritize securing Perdanan. Moreover, according to the tourism potential of the aforementioned forest, they can help the local population increase their income by installing recreational and welfare facilities. Results Various outcomes result from this research that can stand as a base for suggestions in efficient management and utilization of Perdanan forest, including: 1. The results of economic value estimation of Perdanan forest implies high value and importance of this forest. In year, this forest produces use value and non-use value caused by aesthetic, entertainment, climate adjustment, wildlife habitat, protection of plant species, and flowage control to an amount between 5.4 billion and 81.74 billion Tomans. 2. Each year many visits to Perdanan forest take place with average 3.64 visits per person per year that in light of individual consumer surplus of around 53000 Tomans per visit, each year each person pays approximately 0.19 million Tomans to travel to Perdanan, so he evaluates this forest according to this number. 3. Individual expressed WTP per visit is estimated about 18000 Tomans, which if multiplied in average car passengers (4 passengers) equals to 72000 Tomans per car, meaning that the passengers of each car that enters Perdanan site have sum WTP of 72000 Tomans. 4. If the amount of expressed WTP per year per person, i.e. 68000 Tomans, multiplies in the household size, WTP of each household to secure the functions of Perdanan functions will be about 340 thousand Tomans. 5. Investing activities should be devised together with securing the functions and the services of Perdanan and the development of its recreational aspect should not have negative effects on its other aspects. It is possible under the supervision of relevant organizations to prevent, with appropriate planning, visits more than Perdanan’s capacities.
    Keywords: Consumer surplus, travel Cost, willingness to pay, conditional valuation, forest plantation
  • AHMAD Soltani-Zoghi, Afsaneh Serajaddin, Ahmad Fatahi Ardakani * Pages 625-643
    Introduction In this study, the protected area of Hamadan province was investigated and a four-stage decision-making method was used. In the defined model, SWOT analysis is used as the basis for environmental status analysis. Scenarios are analyzed by experts using the ANP method as one of a set of multi-criteria decision-making methods. The purpose of this study is to develop a systematic approach and identify, analyze and rank the proposed scenarios to enhance the potential of the protected area with an emphasis on its role as a key factor in the development of the western region of the country. Protected areas in regional development have been evaluated positively and based on multiple criteria (Mohammadi Deh Cheshme, 2014), Conflicts between key stakeholders that influence the development of protected areas and the management of those areas are a major obstacle to the development of areas in many countries (Coria and Calfucura, 2012). In order to achieve stakeholder collaboration and management of protected areas, a partnership is needed based on the achievement of shared goals (Ghorbani et al, 2015). The use of multi-criteria decision-making models clearly illustrates many of the indicators and risks of activities in protected areas. Risk Ranking Helps Experts Adopt Policies and Strategies to Reduce Risks (Malekhosseini, 1). Risk factors include the destruction of protected areas. Identifying and assessing risks is an appropriate factor to deal with the crises ahead. Environment as an important part of people's lives has attracted the attention of many experts and policymakers. In many countries, laws are in place to reduce activities that lead to pollution and environmental degradation and activities that cause irreparable environmental damage are forbidden (Qavam Abadi, 2013). In the meantime, attention to protected areas and wildlife sanctuaries seems necessary (Majnoonian, 1363). Materials & Methods Hamadan province is located in the west of Iran with an area of more than 19,000 square kilometers. (Figure 1). Hamadan protected areas are a significant part of the western part of the country, well known for its natural diversity and historical values. Management issues in protected areas need to be up Taking into account community needs and economic and environmental principles and ensuring the utilization of all regional development capacity (Bulatović and Marković, 2015), through rational resource utilization, efficient allocation of revenues and assets and improved tourism. Figure 1. Hamadan Protected Areas (Source: Hamadan Environmental Protection Agency) It is very difficult to plan and develop the conditions of a region without considering all the internal and external stakeholders protected area management requires multi-disciplinary research on a wide range of issues, this set of factors depends on the development and implementation of clear and effective management strategies (Montasseri & Ashrafzadeh, 2016). SWOT analysis is a tool for generating and ranking strategies in combination with multiple MCDMs will be significantly enhanced and significantly more applicable. In other words, combining strategy-based approaches such as SWOT with methods used to rank and analyze decisions it enables the expert opinions to be shared with the public as well (Kheirkhah et al, 2014). An integrated global model can be used to rank the proposed scenarios in realizing business prospects based on the integration of strategic goals and SWOT factors, using ANP for multipurpose decision making (Reihanian et al., 2012). The ANP method is one of the multifunctional decision-making techniques widely used by experts in various fields, with the ANP as the best solution for defining a network decision model for achieving predetermined goals in multiple models. The criterion is known (Hamidi et al., 2014). In addition, the advantage of the ANP method over other methods is the ability to measure the relationships between clusters of network structure and the elements within them by adding potential interactions, interdependencies, and decision-system feedback (Sevkli et al., 2012). Protected area management often requires a multidisciplinary approach to the decision-making process. The decision-making process based on the combination of SWOT (strength, weakness, opportunity, and threat) analysis and network analysis (ANP) methods has been presented as a very useful tool in numerous surveys (Back et al., 2015). The main purpose of this study is to develop a strategic decision model that can be used to evaluate alternative scenarios against SWOT factors and strategic goals. The structure of the proposed approach comprises a network with the following clusters: 1. Outlook, 2. Strategic Goals, 3. SWOT Agents, 4. Suggested Scenarios. In order to generate priorities in the (proposed) scenarios, the multi-criteria analytical network decision-making process approach has been used in the study of protected areas. This study provides a model with the possibility of selecting the proposed scenario for achieving a defined perspective based on the interaction between the strategic goals and the SWOT sub-factors. Realizing the proposed approach it is done through four steps. These include: 1) identifying elements, 2 - interacting criteria in the model, 3 - comparing alternatives and sub-factors, 4 - extensive analysis of ANP results. Discussion of Results & Conclusions In addition to SWOT analysis, participants were asked to develop and analyze seven strategic objectives under consideration: 1) Conservation of biodiversity and cultural heritage; 2) increase the level of employment and people's lives; 3) Reforming the social outlook on tourism and the economics of protected areas; 4) Development of small and medium enterprises; 5) Sustainable use of natural resources; 6) Promoting tourism and increasing the number of tourists; 7) Improving cooperation between the private and public sectors. Based on the results of the study, four proposed conservation strategies that were practically feasible were identified as proposed strategies. The strategies examined are Current status, sustainable development, industrial-economic development, and green protection. Reducing the tensions and disparities caused by the interaction between the tourism industry, visitors, the environment and society helps to preserve natural values in protected areas. The primary precondition, appropriate rules, and oversight of the planning and management of protected areas (Grošelj et al., 2015). In addition, an important part of this strategy is in the form of educational activities on nature and cultural heritage aimed at raising awareness of all institutions in the region. The final ranking of the alternative scenarios in the last step of the proposed model was determined by a general analysis of the results of the previous step using the ANP method. The results are presented in Table 1. According to Table 1, it can be deduced that the current situation is the last option backed by experts. The experts do not see the current situation as favorable and believe that the conditions should continue to change and improve strategies. Table 1: Final Priorities for Alternative Development of Hamadan Protected Areas. Table 1: Alternative Ranking Priority Options Priority Ranking current status 0.141 4 Sustainable Development 0.332 1 Green Conservation 0.239 3 Development of industrial-economic structure 0.288 2 Overall the analysis shows that is a feasible and reasonable alternative to protected areas management to replace the "Sustainable Development" option with the one currently in place. To have a positive impact on regional development focusing on tourism. Green conservation is the second alternative that emphasizes environmental protection but does not focus on the economic development of the region. The intensity of environmental protection is very important. Development of industrial-economic structure affects short-term economic growth, but it does not emphasize environmental protection whereas protecting natural areas needs to meet the needs of the next generation. Existing status is rated as the last option in the list of available scenarios and this indicates the existing inefficient status because the weaknesses on which the model is based exist in the same conditions and have been very traumatic. SWOT analysis presents the strategic goals of sustainable development to tourism as the only possible and rational strategy for managing protected areas of Hamadan province. Keyword: SWOT Matrix, Analytic Network Process (ANP), Sustainable Development, Green Conservation, Tourism.
    Keywords: SWOT matrix, ANP Network Analysis, Sustainable Development, Green Conservation, Hamedan
  • Elham Ghehsareh Ardestani *, Mozhde Nafian, Mohsen Bahmani Pages 645-661
    Introduction Urban green space plays an important role in city functioning and its lacking can lead to city life disruption. Urban green space trees include a wide range of environmental, aesthetic, social, physiological and economic benefits. Tree falling due to various factors, especially storms and high-speed winds, can cause severe economic damage, even endangers public health and safety, which is very important due to their widespread presence, especially in the urban areas. It is attracted by municipal green space and urban crisis management to identify and quantify the severity of the hazardous trees and only can provide risk management and suitable preventive measures. Hazardous trees referres to absolutely dried or drying trees, dead components or highly unstable living trees that may be come from structural damage or other factors. These trees pose to a high risk of threatening citizen lives or their property in the urban environment. Normally, healthy trees are more resistant to applied forces and damaged while defective trees are more prone to fracture and eradication in the crown, trunk and root. Hazardous trees management inspects tree risks in the natural and synthetic green space by modeling the behavior and measuring tree conditions in the urban green space. There are several ways to correlate the quantitative and qualitative variables (defects) of trees with their probability of tree hazardous, including artificial neural networks and multivariate regression that have less constraints and assumptions than statistical methods for modeling process. The purpose of logistic regression is describing the relationships between quantitative and qualitative variables as a set of independent variables and risk intensity as a dependent variable. This model maximizes the probability of an event will occur and does not necessarily have a linear relationship between the independent and dependent variables. The neural network model is able to detect the relationship between a set of inputs and output data to predict the output corresponding to arbitrary inputs regardless of the parameters. Recently, studies have been performed on the risk possibility of the trees. Elm tree (Ulmuscarpinifolia var. Umbelifera) belongs to the family Ulmaceae. This genus has various species that are distributed in most parts of the world, especially in Asia, Europe and North America.These trees have relatively dense distribution in the natural forests of Iran, especially the northern and southern slopes of Alborz.They are also used in the most urban green spaces due to their beautiful appearance and wide shade as an ornamental and shaded tree. According to available information, in our country, despite the great extent of the urban green space and its importance and the need to be aware of street tree dangers that pose to a high risk to the life-threatening safety of citizens or their property, on the other hand, there has been limited applied research to predict the risk possibility of the fallen trees. Therefore, this study aimed to determine the most important independent quantitative and qualitative variables affecting the probability of falling trees and developing multilayer perceptron neural network models and logistic regression to predict the probability of falling of elm hazardous trees and also to compare these two models in predicting the probability of falling in a tree in Shariati has done Shahrekord. Material and methods The study area is located in Chaharmahal anf Bakhtiari province, Shahrekord, between 49 degrees and 22 minutes to 50 degrees and 49 minutes and latitude 32 degrees and 20 minutes to 33 degrees and 31 minutes, respectively. The study area was a part of Shariati Boulevard between Basij Square and the intersection of North Ferdowsi Street with a length of 584.13 meters. In order to compare the ability of neural network model with logistic regression to predict the risk possibility of elm trees, the study was performed on 129 elm trees in Shariati St. Boulevard. For this purpose, the variables including tree diameter, tree height, dry branches and woods, cracks, structural and physical weakness (vertical deviation), root and wound and root problems as independent. Quantitative and qualitative variables were classified and the risk classification of elm trees were measured as dependent variables. A complete survey method used to measure and record the quantitative and qualitative variables of elm trees on both sides of the street. Firstly, Normalization of the data was performed and then Principal Component Analysis was used to select the main variables. If KMO (Kaiser-Meyer-Olkin) index is less than 0.5, the data are not suitable for principal factor analysis and if the value is between 0.5 and 0.69, it should be used with higher caution. Also this method used for binary logistic regression models that is a step-by-step method were included in the model. By choosing this method it is possible to isolate significant independent variables related to the probability of elm falling trees (dependent variable). In this study, 70%, 15% and 15% of the total data were allocated to multi-layer perceptron network training, validation and testing, respectively. Qualitative and quantitative variables are considered as input variables and dependent variable of risk intensity class in each tree as output. In order to predict neural network model for prediction of the risk of hazardous elm tree two hazard severity classes were used based on weighting method. According to general approximation theorem, a neural network with a hidden layer and a sufficient number of neurons per layer can approximate any arbitrary continuous function. This study aimed to train neural network from Multilayer Perceptron network of artificial neural networks. Neural network training was used with learning rate reduction 10 (BDLRF). The activity functions in the hidden layers for all networks were considered as sigmoid function and in the output layer linear transfer function. Accordingly, multilayer perceptron network with 5 neurons in input layer, one hidden layer with 20 neurons and one neuron in output layer were used to modeling the risk possibility of elm trees. Surface area under ROC curve and Kappa curve were used to evaluate model prediction accuracy. Results and discussion Results showed that three criteria for branches, root and trunk problems were 87%, 79% and 77%, respectively, and criteria for contact with power lines had the least rate (29%) in the risk of elm trees. Regarding the analysis of principal components tree height, tree diameter, dried branches, structural status or physical weakness (vertical deviation), root problems and advanced decay are the most important variables affecting logistic regression and neural network models. Logistic regression results indicated that with 65.9% confidence iccluding 5 independent variables of tree height, tree diameter, branch and dried branches, structural weakness or physical weakness, advanced decay are predictor variables in probability of tree falling in the present study.The results of the NIMBUS tests to exam the model's explanatory power and efficiency show that the fit of the model is acceptable at the error level of less than 0.01. Independent variables used have moderate explanatory power regarding variance and variations dependent on the probability of falling trees. In fact, these variables were able to explain between 0.33 to 0.456% of tree fall variations. Conclusion Diagnostic criteria for hazardous trees showed that three criteria of dried branches, root problems and trunk cracks had the highest rate in the risk possibility of elm trees. Using the principal component analysis reduced the number of input variables to the models. It also eliminated the correlation between the input variables to the model and easier interpretation of the models. According to this analysis, the variables of tree height, tree diameter, twigs and branches, structural or physical weakness (vertical deviation), root problems and advanced rot were identified as the most important variables. Therefore, two criteria for woods and shoots and root problems in both analyzes are selected the most important variables.
    Keywords: Danger diagnostic criteria, principal components analysis, Receiver operating characteristic, Kappa index
  • Maryam Robati *, Maryam Hosseini, Nabiollah Mansouri Pages 663-678

    The development of the country in recent decades has been largely without sufficient consideration for environmental considerations and has brought irreparable damage to its nature.The development of the country in recent decades has been largely without sufficient consideration for environmental considerations and has brought irreparable damage to its nature. In the past decades, the efficiency and performance of systems, cost-effectiveness and social issues have been the most important parameters in choosing the best option. But as time goes on and environmental consequences such as global warming, air pollution, acid rain, surface and groundwater pollution, soil erosion and desertification, depletion of renewable and non-renewable resources and endangering human health are taken into account. Environmental issues have increased. Cement is one of the important industries in the country that, while producing consumable cement, attracts a large number of young people. Due to the dust particles the plant leaves during cement production, it causes air pollution, the gradual disappearance of vegetation and wildlife. Come back. Concerns over the impact of human-made carbon dioxide emissions on global warming have been raised today. The cement industry is the largest carbon dioxide emitter in the industry. Cement is an important source for planning to reduce carbon dioxide emissions. Cement production in addition to producing carbon dioxide also releases millions of tons of cement kiln dust, causing respiratory distress. The cement factory has several stages of production with different technologies that produce the product, ie cement of different quality and different types. The production of this kind of material needed for construction and many other works such as construction and ... Pollutions such as air pollution by gases such as SO2, NO, VOC, CO, CO2 and soil pollution and water pollution are caused by water consumption in this industry. Cement consumption in countries can be considered as an indicator of their preference. However, depending on the climate of each country. , The type of cement usage and other essentials. In our country over the past few years the need for this Important engineering material has increased and this has led to the establishment of numerous factories throughout the country. Greenhouse gases are emitted from a wide range of industrial activities. The main sources of emissions are those industrial processes in which materials are converted physically or chemically. For example, the long furnace process in the iron and steel industry, Production of ammonia and other chemicals using fossil fuels as raw materials and cement industries are among the industrial processes that emit significant amounts of CO2. During these processes, various greenhouse gases including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are released. The largest source of CO2 emission in the industry after the energy sector are cement plants. The cement production process directly and indirectly produces carbon dioxide gas. Indirect generation due to the energy consumed for cement production and direct production. The chemical process is called calcite. Thus, the limestone process with the molecular composition of CaCO3 is heated to lime with the molecular composition of CaO and CO2 is released. In Iran, 60.6% of the carbon dioxide produced in the cement industry goes back to this process. In the past decades, the efficiency and performance of systems, cost-effectiveness and social issues have been the most important parameters in choosing the best option. But as time goes on and environmental consequences such as global warming, air pollution, acid rain, surface and groundwater pollution, soil erosion and desertification, depletion of renewable and non-renewable resources and endangering human health are taken into account. Environmental issues have increased. Cement is one of the important industries in the country that, while producing consumable cement, attracts a large number of young people. Due to the dust particles the plant leaves during cement production, it causes air pollution, the gradual disappearance of vegetation and wildlife. Come back. Concerns over the impact of human-made carbon dioxide emissions on global warming have been raised today. The cement industry is the largest carbon dioxide emitter in the industry. Cement is an important source for planning to reduce carbon dioxide emissions. Cement production in addition to producing carbon dioxide also releases millions of tons of cement kiln dust, causing respiratory distress. The cement factory has several stages of production with different technologies that produce the product, ie cement of different quality and different types. The production of this kind of material needed for construction and many other works such as construction and ... Pollutions such as air pollution by gases such as SO2, NO, VOC, CO, CO2 and soil pollution and water pollution are caused by water consumption in this industry. Cement consumption in countries can be considered as an indicator of their preference. However, depending on the climate of each country. , The type of cement usage and other essentials. In our country over the past few years the need for this Important engineering material has increased and this has led to the establishment of numerous factories throughout the country. Greenhouse gases are emitted from a wide range of industrial activities. The main sources of emissions are those industrial processes in which materials are converted physically or chemically. For example, the long furnace process in the iron and steel industry, Production of ammonia and other chemicals using fossil fuels as raw materials and cement industries are among the industrial processes that emit significant amounts of CO2. During these processes, various greenhouse gases including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs) are released. The largest source of CO2 emission in the industry after the energy sector are cement plants. The cement production process directly and indirectly produces carbon dioxide gas. Indirect generation due to the energy consumed for cement production and direct production. The chemical process is called calcite. Thus, the limestone process with the molecular composition of CaCO3 is heated to lime with the molecular composition of CaO and CO2 is released. In Iran, 60.6% of the carbon dioxide produced in the cement industry goes back to this process.

    Keywords: Ecosystem services, LCA, TES, cement industry, Sima Pro Software
  • Fatemeh Adelisardou, Hamid Reza Jafari *, Bahram Malekmohammadi, A. R. Karbassi Pages 679-691

    An integrated framework model for the analysis of sustainability in the agriculture water system (Case study, Jiroft plain- Kerman) Fatemeh Adelisardou, Hamidreza Jafari , Bahram Malekmohammadi, Abdolreza Karbsai 1. Ph.D. Candidate of Environmental Planning, School of Environment, College of Engineering, University of Tehran (fatemeh.adeli67@ut.ac.ir) 2. Professor, School of Environment, College of Engineering, University of Tehran 3. Associated professor, School of Environment, College of Engineering, University of Tehran(malekb@ut.ac.ir) 4. Professor, School of Environment, College of Engineering, University of Tehran(akarbasi@ut.ac.ir)

    Introduction

    Groundwater depletion is one of the main factors that determine the sustainability management of groundwater. Recently it has become a significantly debated topic, particularly for food production in the agricultural ecosystem of arid regions. Numerous groundwater scholars have tried to estimate the results and causes and of groundwater decline, and have shown that groundwater is being used at rates that exceed the natural rates of recharge, globally. Both climate change and excessive extraction, for irrigation, were responsible for groundwater level decline. In this study, groundwater depletion and its dynamic factors, including agricultural activity and metrological drought indexes, were investigated in the Jiroft plain- south of Kerman.

    Material and Methods

    The present study with an integrated approach investigated the groundwater level's change using statistical methods. In other to determine the role of agriculture activity on the groundwater level, the performance of the selected crop was determined. The main criteria for the selected crop were the highest area under cultivation. Selected crops were including wheat, barley, corn, watermelon, cucumber, potato, onion. In the next virtual water of selected crops based on blue and green water was calculated. On the other side, to determine the role of drought, the parameter in reducing groundwater level 6 meteorological indicators of SPI, RAI, DI, ZSI, CZI and, MCZI were examined in a ten-year period using RDIT software was determined.

    Results

    The results of this study show one-meter depletion in groundwater levels each year (Fig1). The results of virtual water offer the production and export of agricultural products with low economic value. Fig.1. The trend of groundwater level in the Jiroft plain Drought indicators are the most widespread years of severe drought related to the years 1379, 1383, 1389, and 1390 (Fig2). In other years, there is a moderate but frequent drought due to the dry nature and low rainfall in the region. In rare cases, it has faced a situation other than the drought. Fig.2. Status of the study area in terms of meteorological drought indicators The results showed that among the selected crops with the highest level of cultivation in the study area, wheat, and barley with 2621 and 2079 (m3/kg) had the highest amount of virtual water consumption. It is also worth mentioning that products such as watermelon need an average of 314 (M3/Kg) of green and blue virtual water. These results mentioned the trend of agricultural activity moved to low-value crops with the high water demand that has the largest share of exports.

    Conclusion

    This study revealed that human activities have a strong influence on the groundwater decline. At the same time, the effect of metrological drought was insignificant. Results from driving force analysis indicated that agriculture activity was the primary factor, and temperature and precipitation could be used as definite criteria for groundwater recharge. Therefore the problem of groundwater in the agricultural ecosystems is severe and needs to be highly valued. Modern management of farms with crops that need less water and produce more could also be useful for water-saving. Also, it is crucial to raise the awareness of farmers regarding water-saving. Keywords: Groundwater level, Virtual water, Metrological drought, Jiroft plain

    Introduction

    Groundwater depletion is one of the main factors that determine the sustainability management of groundwater. Recently it has become a significantly debated topic, particularly for food production in the agricultural ecosystem of arid regions. Numerous groundwater scholars have tried to estimate the results and causes and of groundwater decline, and have shown that groundwater is being used at rates that exceed the natural rates of recharge, globally. Both climate change and excessive extraction, for irrigation, were responsible for groundwater level decline. In this study, groundwater depletion and its dynamic factors, including agricultural activity and metrological drought indexes, were investigated in the Jiroft plain- south of Kerman.

    Material and Methods

    The present study with an integrated approach investigated the groundwater level's change using statistical methods. In other to determine the role of agriculture activity on the groundwater level, the performance of the selected crop was determined. The main criteria for the selected crop were the highest area under cultivation. Selected crops were including wheat, barley, corn, watermelon, cucumber, potato, onion. In the next virtual water of selected crops based on blue and green water was calculated. On the other side, to determine the role of drought, the parameter in reducing groundwater level 6 meteorological indicators of SPI, RAI, DI, ZSI, CZI and, MCZI were examined in a ten-year period using RDIT software was determined.

    Results

    The results of this study show one-meter depletion in groundwater levels each year (Fig1). The results of virtual water offer the production and export of agricultural products with low economic value. Fig.1. The trend of groundwater level in the Jiroft plain Drought indicators are the most widespread years of severe drought related to the years 1379, 1383, 1389, and 1390 (Fig2). In other years, there is a moderate but frequent drought due to the dry nature and low rainfall in the region. In rare cases, it has faced a situation other than the drought. Fig.2. Status of the study area in terms of meteorological drought indicators The results showed that among the selected crops with the highest level of cultivation in the study area, wheat, and barley with 2621 and 2079 (m3/kg) had the highest amount of virtual water consumption. It is also worth mentioning that products such as watermelon need an average of 314 (M3/Kg) of green and blue virtual water. These results mentioned the trend of agricultural activity moved to low-value crops with the high water demand that has the largest share of exports.

    Conclusion

    This study revealed that human activities have a strong influence on the groundwater decline. At the same time, the effect of metrological drought was insignificant. Results from driving force analysis indicated that agriculture activity was the primary factor, and temperature and precipitation could be used as definite criteria for groundwater recharge. Therefore the problem of groundwater in the agricultural ecosystems is severe and needs to be highly valued. Modern management of farms with crops that need less water and produce more could also be useful for water-saving. Also, it is crucial to raise the awareness of farmers regarding water-saving. Keywords: Groundwater level, Virtual water, Metrological drought, Jiroft plain

    Keywords: Groundwater level, Virtual water, Metrological drought, Jiroft plain
  • Leila Kowkabi * Pages 693-709

    Introduction- Over a long period of time, rural landscape has been established by the relationship between nature and humans. Landscapes are recognized as a part of the natural, historical, cultural, and scientific heritage. The rural landscape patterns are particular contexts because of having cultural characteristics. Humans have survived by gathering wood and grass for fertilizer, fuel, fishing in the rivers, creating agricultural fields, burning woodlands and construction materials. They expanded the agricultural fields by managing water and rural forests serve as the sink of resources used by humans for daily life and agriculture. Nowadays People do not need organic fertilizer and housing materials as before. As local residents in rural areas tend to use modern technology, preservation of cultural values and natural attractions should not be underestimated, so many criteria must be considered in order to achieve sustainability. The rural landscapes are particular due to cultural characteristics. The definition of landscape can be identified as an area where is the result of nature and human interaction. The rural landscapes are particular due to cultural characteristics. As local residents in rural areas tend to use modern technology, preservation of cultural values and natural attractions should not be underestimated. In rural contexts, primary activities such as agriculture and forestry are no longer the only ones that influence landscape structures. Some rural areas have potential value due to outstanding nature and unique landscape; While soil fertility and the capacity to produce goods were the basis of landscape appreciation in the past, it is now aesthetic, environmental, and heritage qualities which make landscapes appreciable. Human manipulations of the nature which are basically due to socio-economic development have been on the rise in the world since the industrial revolution. These have affected the rural ecosystem entity, by decreasing biodiversity, destroying amenities, and so on. While local residents in rural areas tend to use modern technology and development, preservation of traditions and cultural values, use of local materials and methods of building and conserving the natural attraction points should be highly emphasized. Materials & methods- This research was done by describing the process of developing a methodology for investigating the fundamental characteristics of the sustainable rural landscape in historic village “Furg”. It is vital to study those areas where have undergone the least changes in order to refrain further unnecessarily changes and retain sustainability in both cultural and constructional sectors. Furg is a village in Darmian Rural District, in the central district of darmian county, south khorasan province, Iran. Furg Castle is located on the north side of the Village at an altitude of 1840 meters on the edge of the heights of Darmian Valley leading to Asadiyeh plain. It has a good strategic situation, because it has a commanding view of the entire village, farms and roads around its eastern region. The researcher documented the process and illustrated an individual’s search for the method that would suit the research problem. Some qualitative researchers believe that in-depth qualitative research is especially well suited for revealing higher-level concepts and theories that are not unique to a particular participant or setting. The “grounded theory” and “participant observation” are the qualitative methods that particularly suited to the areas of rural social research. Grounded theory is an analytic method for constructing theories from inductive qualitative data. Data collection and analysis inform each other in an iterative process as researchers make their ideas. It has been done with Memo-writing and Theoretical sampling; Memo writing to elaborate categories, specify their properties, define relationships between categories and identify gaps. The new features enhance the brief sections headed by clear section headings. Discussion & Results- This research reviews the backgrounds and meanings of “fundamental of landscape characteristics in Furg. The rural landscapes have become a space with different functions from those of past. There are many criteria which must be considered in order to achieve sustainability; such as specific cultural backgrounds, which have influenced on the settlement patterns of regions and countries. The main driving force in landscape change is the human impact on rural landscapes. The changes in agricultural systems and socio-economic environments in rural landscapes, have led to changes in rural ecosystems. As a result, human activities in the areas create special features in rural landscape. The research analyzed the rural landscape and finally indicates the main characteristics that shape the unique landscape of Furg village; and shows that the landscape is seen here as symbols of these bachground. The nature and the special manner of lives have reduced the possibility of cultural interference; as a result it keeps their old customs and traditions. Thus, unlike other countrys’ rural areas they did not replace the building materials. The results show that Furg's rural landscape is based on characteristic features; including: "Homogeneity of Village Texture with Context", "Rise of Architectural Pattern by Land and Climate Form",” lack of diversity of agricultural perspective", "Overcome beliefs and opinions on the development of the rural landscape" and "security-based development perspective and their influence on rural landscape". Conclusions- Each part of the landscape has its distinctive character, which offers a unique sense of place. Current condition of a landscape can be a reliable indicator of future trends and areas in need of further attention. The economy of rural areas has always been strongly dependent on natural resources exploitation. In recent years the lifestyles of most people in rural areas have changed due to modern technology. Recent technological advancements in exploitation, loss of rural livelihood, and increased social demand for the amenity aspects of these resources have dramatically changed rural landscape and visual quality. The cultural change has affected the form and appearance of villages. Many villagers have left to bigger towns and cities. The main issue is that changes are growing very rapidly. Furg has maintained its original architecture, traditional customs and the language. They have barely changed due to the isolated location of the village. This study calls for further research to establish stronger links between sustainable landscape theories and rural sustainability. Despite the limitations, we believe this framework is a useful approach to rural landscape sustainability.

    Keywords: sustainable Rural landscape, indicators, Grounded theory, participant observation, historic village of Furg
  • Fatemeh Janpoor, Ali Torabian *, Homayon Ahmad Panahi, Majid Baghdadi Pages 711-724
    Introduction With population growth, industrial development, and increased pollution of freshwater sources, access to adequate and safe water has become a serious crisis in some countries. Most of currently in use water disinfectants are not fully effective in destroying pathogenic microorganisms in drinking water, or they may produce side products that are harmful to human health. Also, some of these disinfectants are toxic. Today, finding special methods with high efficiency, appropriate cost, and impact on the wide range of pathogenic bacteria, has been highlighted because of resistant microbial contamination of conventional treatments, as well as other disadvantages of existing disinfection methods. At present, nanoscale with a multi-purpose antibacterial potential has created hopes for solving the problem of drug-resistant bacteria. Silver is one of the most effective antibiotics known in human history and can destroy more than 650 different bacteria in few minutes, and have been used in antimicrobial applications since the 19th century. Despite the good antibacterial property of silver, silver nanoparticles due to its surface properties and photocatalytic properties can facilitate oxidative damage to nearby cells, and also have remarkable bio-toxic activity due to the sustained release of Ag +. A solution to prevent the release of silver nanoparticles and silver ions into the water was found to utilize the antimicrobial properties of nano silver. A new method of antimicrobial agents is to place an antimicrobial agent on the surface of carriers, such as graphene oxide, activated carbon and composite formation. Graphene oxide, has been a good selection for composite materials. GO contains two-dimensional materials composed of carbon atoms in a crystal honeycomb grid.). GO, and composites of GO using chemical and physical mechanisms have been reported to have antibacterial properties. Also, researchers have shown that due to the synergistic effect of silver nanoparticles and graphene oxide, the combination of these two substances has a better antibacterial effect. Despite the antimicrobial properties of GO-Ag nanocomposite, due to the nanoscale thickness of these materials, GO-Ag nanocomposite is stable in water, and it is not possible to remove it from drinking water with conventional methods. Therefore, for the use of GO-Ag nanocomposites to disinfect drinking water, a method should be used that can stabilize these substances and prevent them from releasing and suspending in water. Capacitive deionization (CDI) technology is a method for removing ions from brackish water with active carbon electrodes. The overall efficiency of CDI system depends on the surface properties of the electrode, such as the specific surface area, the distribution and porosity size, the absorption characteristics and the main chemical groups at the electrode surface. The good results of a capacitive deionization system in water desalination, have the potential to use this system for the removal of organic matter, microbial agents, and other water contaminants. The capacitive deionization process is a continuous flow process, which is performed by ion absorption and ion desorption alternating cycle, to remove ions from water and regeneration stage, respectively which is applied to a direct voltage. Due to the low energy consumption (2 V), good regeneration ability, and Non-use of chemicals at different stages of desalination, the CDI system has been considered The CDI technology with enhanced and improved electrodes can be a good solution for disinfecting and desalination water. In this research, a new coating of graphene oxide dendrimer silver on the activated carbon electrodes was introduced for high desalination and disinfection capacity of water by a capacitive deionization-disinfection system. 2. Methods and method  Materials Graphene oxide (GO), Activated carbon (AC), hydrochloric acid (HCL), Sodium hydroxide (NaOH), Epichlorohydrin (C3H5ClO), Sodium borohydride (NaBH4), Sodium Sulfide (Na2S), sodium acetate (CH3COONa), silver nitrate (AgNO3) were supplied from Merck Co, Germany.  Method  Dendrimer grafting on the graphene oxide (GO-D)  Preparation of Silver nanoparticle  Nanocomposite CDID Electrode Fabrication  Measurements and characterizations - FTIR - TGA - FE-SEM/EDS  Initial solution preparation - NaCl solutions with different TDS (1000 to 20000 mg/ L) - initial MPN of coliform (1000, 5000, 10000 and 100000 MPN) 3. Results and discussion 3.1. Effect of initial TDS and contact time Nacl solution at concentrations of 1000, 1500, 5000 and 20,000 mg / L was tested for a 5 to 90 minutes’ contact time to determine the deionization ability of the water. to compare the salt solution and the actual sample of water, Caspian Sea water was tested with a TDS of 20000 mg/l. Experimental results show that the system has high capability of deionizing water. Also to determine the simultaneous deionization and disinfection capability, NaCl solution with concentrations of 500, 1000, 1500 mg/l and 5000 mg/l was tested with 10000 MPN of initial coliform and 15 to 60 minutes’ contact time to determine the impact of TDS on coliform removal Experimental results showed that the system had ability of removing 80% of water salinity simultaneously with water disinfection. 3.2. Effect of initial coliform One of the parameters in the evaluation of the disinfection activity has been initial coliform. For this purpose, various coliforms (500, 1000, 10000 and 100000 MPN) were tested in NaCl solution 500 mg/,30 and 60 minutes’ contact time. Killing rate of coliform in the initial 500 and 1000 MPN was 99.9% at 30 minutes. This retention time was similar to the time required for disinfection in the conventional chlorination system in water treatment plant but without the use of chemicals for disinfection and remaining by product in disinfected water. It also had the ability to remove 99.9% of 10000 MPN in 60 minutes. 4. Conclusion GO-D-AG is a new nanocomposite, synthesized from graphene oxide with a new generation of dendrimers, with silver nanoparticles on branches, to make new electrodes for CDID system. A thin layer of GO-D-Ag nanocomposite will be located on the surface of carbon electrodes. Due to the covalent bonding between dendrimer and graphene oxide and the strong complexation between sulfur and silver nanoparticles in the branches, this system is a safe solution for the use of silver nanoparticles in water disinfection. The amount of nanoparticles used in the electrodes had a great effect on the disinfection property of the capacitive deionization system. Contact time was also an effective factor in reducing coliform from water. Experiments were evaluated for 15 to 120 minutes on contaminated water with coliform content of 1000 to 100000 MPN. This electrode had a disinfection effect of at least 99.9% (4 Log Reduction of coliform) and 90% (5 Log Reduction of coliform) with 60-minute contact time and completely removed 100000 MPN of coliform in 120-minute contact time. Experiments have shown that these electrodes were capable of disinfecting water at salinity levels up to 5000 mg/l, whereas in the previous research, only disinfection at 200 mg / L was performed by CDI system . Disinfection by this CDID system with the new generation of the electrode can be an excellent alternative to traditional disinfection processes because it had low energy consumption (2 V uses for disinfection), quick and useful regeneration, and disinfection without any byproduct.
    Keywords: capacitive deionization, Disinfection, silver nanoparticle, dendrimer
  • Ahmad Haghgoo, Ozeair Abessi *, Ali Rahmani Firoozjaee Pages 725-740
    Introduction Increases in the world population and changes in the pattern of urban life together with the countless sources of air pollutants in semi-closed spaces have changed the air space of our cities into a hostile environment. Therefore, the problem of air pollution is not only limited to the outdoor environment but also became a real problem in indoor spaces. In modern cities, people spend 70-90 percent of their time in indoor spaces and their activities are limited more to these environments. Carbon monoxide is one of the most dangerous gaseous pollutants in the buildings with both residential and industrial operations that are frequently reported to cause diseases and death. Carbon Monoxide (CO) is a colorless, odorless, and tasteless flammable gas that is slightly positively buoyant compare to air. Carbon monoxide is produced from the partial oxidation or burning of fossil fuel (coals, oil, and natural gas) or any other carbon-containing compounds. CO can build up indoor spaces and poison people and whoever (animals and plants) breathe it. Poisoning due to Carbon monoxide is a common type of fatal air poisoning reported around the world. The most common symptoms of CO poisoning are headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion. Many researchers such as Sykes and Walker (2016) and Levy (2015) have investigated the health effects and the risk of CO poisoning on resident safety and peace. Various concentration of CO is found in fumes produced by burning fuel in workshop buildings and Industrial Units. It is ranged from 2 to 5 percent (20,000-50,000 ppm) and can cause long-term health problems to workers who breathe it. Various health organizations have established the Carbon Monoxide (CO) concentration limits. ASHRAE sets outdoor maximum levels at 35 ppm (1 hour averaging) and 9 ppm (8 hour averaging), while the World Health Organization limits CO concentrations based on exposure time ranging from 90 ppm (15-minute exposure) to 10 ppm (8-hour exposure). The ASHRAE indoor's maximum concentration limits for CO in industrial units is 50 ppm (8 hour averaging), which is usually hard to meet in place works and workshops. Harmful health effects of carbon monoxide make it essential to be able to predict the behavior of flow in indoor spaces for the successful implementation of any mitigation measures. Natural or forced ventilation is the simplest way to reach acceptable indoor air quality standards. Numerical and experimental models are common tools to predict the behavior of airflow in indoor and outdoor spaces. Experimental works also by providing a benchmark for the calibration of the numerical works and by developing the empirical equations for the prediction of flow patterns are commonly used to define airflow in indoor spaces. Modeling of airflow through the simulations of flow in the water tank has rarely been investigated. Chen et al, (2010) used a water tank and LIF technique to simulate contaminant distribution inside an airliner cabin using a one-tenth scale water model. The same approach has been followed in the current study. A small scale model of a workshop has made to simulated airflow distribution and transport. To correctly represent the flow, a small-scale model should be designed based on similarity analysis, in which the relevant dimensionless flow parameters are identical between small- and full-scale. The similarity of the forces is reached by the equality of Froude or Grashof and Prandtl numbers. Materials and Methods For the flow of carbon monoxide, regarding the density difference between CO plume and air the forces of inertia and buoyancy (density difference) are dominated. Due to the high turbulence of the flow, the viscous force is negligible compared to the two aforementioned forces. Therefore, the Froude number that consists of the important properties of the flow can be considered to set the similarities. On the other hand, regarding low velocities compare to the speed of sound (Mach number <1) the compressibility of flow can be ignored. So, the density difference and inertial forces are the only important forces and flow can be assumed incompressible carefully. In this study, a simple regime of CO plume from a point source in a workshop building has been investigated. The building is a 3 mm perspex box that is 30 cm long, 30 cm wide and 35 cm tall with the sloping roof at both sides. The flow of contamination is a CO plume on the floor with a diameter of 1 cm. The discharge speed is 10 cm/s and the CO concentration is 20,000 ppm, so the Froude number is 1.44 and the Reynolds number is equal to 1124. A roof window, 1 cm wide and 10 cm long, is considered for the outflow. The experimental works are performed at the Environmental Fluid Mechanic Laboratory of Babol Noshirvani University of Technology, Iran, using the Three-Dimensional Laser-Induced Fluorescence (3DLIF) system that especially developed for this purpose. The scaled experimental test facility placed upside-down fully submerged in the water tank. Conducting the experiment in a water tank besides index-matching is simpler to quantify flow mixing and dilution using the illumination of fluorescent. Discussion of Results In this study, the behavior of a plume of carbon monoxide in the indoor space of a stationary environment was investigated where no wind or forced ventilation implemented. CO is less dense than the ambient air and the flow moves upward due to its initial buoyancy. The flow reaches the steady-state condition after some seconds from the beginning. The concentration of contamination decreases due to flow entrainment and mixing while plume moves upward. The dimensions of buildings and outflow roof window determine the time requires to reach steady-state and it was 50 seconds for this experiment. So the experiment was recorded after this time when it became time-independent. This time would be exactly equal for the same size building in either water or air. However, the time is proportional to T_P/T_M =√(L_P/L_M ) between model and prototype. For the flow speed also the same relation i.e. V_P/V_M =√(L_P/(L_M )) , is established. The mixing and dilution of the contamination are proportional to flow speed and its initial buoyancy. Due to the dominant forces, the flow goes upward to eventually reaching to the ceiling, then moves outward from the roof widow up to reach the steady-state condition. In the uniform steady flow of CO smoke, a stratification forms in the building in which the concentration gradually decreases from the floor (20,000 ppm) up to the ceiling (2,600). As a result of this study, self-similarity was observed for the profile of concentration and plotted at different locations from the source ( ). The 2D configuration of flow, changes in flow width and centerline concentration are also plotted. Conclusions In this study, utilizing the LIF system, the spatial and temporal changes of CO concentration from a plume of contamination in a workshop have been investigated. Concentration variation along the centerline is plotted along with the changes in flow width and pollutant distribution in the building. For the aforementioned dimension with a point source at the floor and a roof window at the ceiling, it observed that the flow reaches the steady-state condition after about 50 seconds in which as stable stratification forms in the building. The CO concentration gradually increases from zero to maximum from the floor up to the ceiling. The pattern of changes depends to flow initial fluxes and the roof window's dimensions. The effect of walls on entrainment restriction and the ceiling on flow re-entrainment were observed and plotted as the self-similar profiles. The concentration of CO found in the range of danger at the height of human respiration in this building. It shows that natural ventilation can not decrease the high concentration of CO in this plume. Forced or mechanical ventilation is required.
    Keywords: Pollution plume, Transport, Distribution, experimental simulation, Lif
  • Maryam Izanloo, Mahdi Farzadkia, Ahmad Jonidi, Ali Esrafili *, Hosssien Karimi, Sahar Farokhi Pages 741-753
    Introduction
    Today what has attracted more than each other category of human thoughts is the problem of environmental pollution by heavy metals, which affect the health of humans and humans due to their lack of absorption and the effects of physiologic effects at low concentrations. Cadmium has been identified as a carcinogen due to severe toxic effects on human organs. The sources of cadmium inputs to aqueous solutions include wastewaters from chemical fertilizers, pesticides, mines, melting, building batteries, pigments, stabilizers, and alloys, plating, sewage sludge, plastics and synthetic rubber.The daily intake of this substance is 10-35 μg / liter. Smoking is another source of cadmium exposur. According to Standard 1053 of Iran, the maximum allowable cadmium concentration in drinking water, based on the average daily consumption of drinking water equal to 2.5 liters, for a human with 70 kg is 0.005 mg/l. According to the World Health Organization's 1996 standard, cadmium concentrations in drinking water were limited to 0.003 mg /l. Newadays, There are several removal processes for heavy metals from wastewater such as; chemical deposition, membrane processes, ion exchange, coagulation, flocculation and absorption. However, absorption method is one of the most effective and efficient methods. In fact, it can be argued that in many cases protective shells not only prevent the oxidation of iron, but can also be used for more function. Magnetic oxide nanoparticles are most often used in aqueous solutions due to their many advantages such as high surface to volume ratio, very small size, high reactivity, and better absorption of toxins and heavy metals. But one of the main challenges of pure iron oxide nanoparticles is their high chemical activity, which makes it easy to oxidize against air (especially magnetite) or in acidic aqueous media. This will result in the loss of magnetism and the dispersion of iron oxide nanoparticles. Therefore, in order to prevent this occurrence, providing the appropriate coverage level and developing some effective protection strategies to maintain the stability of magnetic iron oxides is very necessary.Protective shields (especially silica), in addition to stabilizing iron oxide nanoparticles, have the benefits of preventing the accumulation of iron nanoparticles, increasing the compatibility of magnetic nanoparticles with solid matrices in the environment, creating graphene and bonding more nanoparticles with organic ligands, reducing the release rate of the oxygen molecule To the magnetic nuclei and to stabilize the crystalline structure of nanoparticles at high temperatures.
    Materials and methods
    A two-step method was used to prepare magnetic nanoparticles coated with silica. In this study, cadmium adsorption was performed on adsorbent Fe3O4 @ SiO2 iron oxide mesopes in a closed reactor within 100 ml echinoderms. In the first step, the iron oxide nanoparticles were synthesized via a simple co-precipitation and then, in the second step, the tetraethyl ortho-silicate was used to coating it. For this purpose, 22 g of Fe2Cl3.6H2O and 8 g of FeCL2.4H2O were mixed to 400 mL of deionized water and the resulting mixture was stirred for 1 h in the presence of nitrogen gas at 80 ° C. Then, 15 mL NH4OH (25 % w/w) was added drop wise to reach pH 9. The produced nanoparticles were collected from the solution using an external magnetic field (1.2 Tesla) and washed several times with ethanol and deionized water and then, dried in an oven at 60 ° C for 24 hours. In the second step, a tetraethyl ethoxylan (TEOS) material was used to mixter of Fe3O4. therefore, the nanoparticle was synthesized in the previous stage with 15 ml of TEOS, 6 ml of ammonia (25%), 80 ml of ethanol (65%) and some of the deionised water injected into the reactor. At the same time, a litttle amount of ammonia used, because it reduces the size of the nanoparticles and increases the number of free groups of silanol (Si-OH) on the nanoparticle surface and activates them. Finally, the supernatant was isolated by magnet and washed five times with distilled water and ethanol and then, dried in an oven at 60 ° C for 24 hours. X-ray diffraction (XRD), infrared spectrometer (FT-IR), transient electron microscopy (TEM) and scanning electron microscope (SEM) were used to study absorbent properties. Discussion of the
    Results
    The calculation of the adsorbent isoelectric point (pHZPC) is an essential part of the adsorption process. The isoelectric point is called the pH where the adsorbant has a neutral load. At this point, due to the low electrostatic interactions between adsorbent and adsorbent, the amount of absorption of pollutants is reduced. However, at pH <pHZPC, adsorption load is negatively charged due to the presence of H + ions and at pH> pHzpc the adsorption load is negatively affected by the presence of active hydroxide ions (OH). The pHZPC of Fe3O4 @ SiO2 nanoparticles is calculated to be about 3.26. Therefore, according to the above, it can be stated that the adsorbent has a negative charge in pH>3/26. The maximum removal percentage and its adsorption capacity were 72.86% and 33 mg/g at pH 5, respectively. In this regard, pH 5 was used to continue the experiments. The cadmium adsorption was investigated at interval of 10–60 min. The results indicated that cadmium adsorption increased with increasing contact time. In the present study, iron oxide magnetite nanoparticles coated with silica as adsorbent in the cadmium adsorption process were used. Then, the effect of important pH and contact time factors on the removal of cadmium from aqueous solutions and kinetic, isotherm and thermodynamic models were investigated. According to studies, It was found that the adsorption reaction rate increased by the adsorbent at initial times. The main reason is the availability of more active cadmium sites on the adsorbent surface, which over time will increase the amount of cadmium removal from the solution.The values of Langmuir and Freundlich isotherms parameters of the cadmium adsorption process by Fe3O4 @ SiO2 are shown in Table 2. The results showed that regression coefficients of Langmuir and Freundlich isotherm models were determined to be 0.984 and 0.957 ,respectively.The values obtained from the kinetic parameters of the first-order, second-order kinetics model are shown in Table 3. This suggests that the adsorption of cadmium on the adsorbent surface is more consistent with and consistent with the Langmuir isotherm model. In order to analyze the results of the cadmium uptake process at the synthesized absorbent level, first-order and pseudo-second order kinetics models were used. According to Table 3, the regression coefficient in a pseudo-second-order kinetic model is higher than that of the pseudo-first kinetics (R2 = 0.991). In addition, in this study, by increasing the solution temperature from 25 to 45 degrees Celsius, the percentage of cadmium removal increased 72.3 to 78.12 percent. Increasing the absorption of pollutants at high temperatures can be due to the combined desire of adsorption sites for metal ions. In this way, the increase in temperature leads to an increase in kinetic energy and an increase in the number of collisions between the adsorbent and the absorbent and decreases the viscosity of the soluble, thus facilitating the addition of absorbed ions to absorption positions . Based on experimental results and regression coefficient, cadmium adsorption on Fe3O4@SiO2 nanoparticles has been followed by a pseudo second-order kinetic and Langmuir isotherm. Finally, the thermodynamic studies showed that the adsorption process is of endothermic and spontaneous nature.
    conclusion
    Morphology analysis showed that Fe3O4@SiO2 nanoparticles had a size of 15 nm approximately. The results of adsorption kinetics indicate that cadmium adsorption on adsorbent follows a quadratic kinetic model. The obtained optimal conditions for the cadmium adsorption were included, pH 5 and reaction time 30 min. Based on experimental results and regression coefficient, cadmium adsorption on Fe3O4@SiO2 nanoparticles has been followed by a pseudo second-order kinetic and Langmuir isotherm. Examining isothermic models suggests that this process follows the Langmuir isotherm model, which indicates homogeneity and the single-layer absorption process.
    Keywords: Adsorption, Cadmium, kinetic, Isotherm, thermodynamic