f. ghasemifard

The presence of copper oxide next to gold increases the consumption of cyanide in the cyanidation process, reduces the absorption of gold on carbon, and causes many problems in the downstream processes of elution, electrowinning, and smelting. In the current research, increasing the recovery of gold dissolution and its selective adsorption on activated carbon using ammonia additive and the effect of different factors such as the type of ammonia additive, changing the system of contact of gold with carbon from CIL to CIC, and adding hydrogen peroxide and cyanide to the filtered solution were studied. The findings showed that adding ammonium chloride or liquid ammonia to the cyanidation solution, in the sample with high copper grade (1% copper), and in the sample with medium copper grade (0.5% copper), increased the dissolution recovery by 60% and 30%, respectively. Also, the recovery of gold adsorption on activated carbon in sample with a grade of 0.5% copper increased from about 25% during the normal CIL process to about 100% during the ammonia cyanidation process in the form of CIC. Results showed that liquid ammonia provides up to 10% higher dissolution recovery and up to 3% higher absorption recovery compared to ammonium chloride, while reduces the consumption of cyanide by half and the amount of copper absorption on carbon by a third.

Due to the significant effect of motor skills on developmental areas in children with visual impairment, the need to measure gross motor skills and the lack of valid and reliable tools in this field is essential. This study conducted with the aim of determining psychometric characteristics of the second version of the Test of Gross Motor Development (TGMD-2) in children with visual impairment aged 7-10 years in Tehran.

In this descriptive and psychometric analysis study, criterion-related validity and Spearman correlation were used. Concurrent validity was assessed using the second edition of Movement Assessment Battery for Children (MABC-2). In previous studies, content and face validities were performed and construct validity was not possible to measure because of the limited sample size. To evaluate the reliability of the TGMD-2, a one blinded researcher measured the gross motor skills of 50 girls and boys aged 7-10 years with visual impairment with a one-month interval in three schools of visual impaired children (Mohebbi, Khazaeli and Narjes). Cronbach's alpha for internal reliability and Intraclass Correlation Coefficient (ICC) for external reliability were used. Data were analyzed using SPSS version 22 with a 95% confidence interval and a significance level of 0.05.

Concurrent validity of the sub-scales of TGMD-2 and MABC-2 tests were significant (P <0.05) in a high level. Pearson correlation coefficient between subscales of locomotion and balance and between object control and aiming-catching of the TGMD-2 and of MABC-2 were 0.80 and 0.75, respectively. Internal and external reliability of TGMD-2 were confirmed. Cronbach's alpha for the locomotion and object control subscale were 0.97 and 0.96, respectively. The Intra Class Correlation Coefficient (ICC) of the TGMD-2 was 0.97(P <0.05).Also, inter rater and intra rater were 95% and 97%, respectively for TGMD-2.

The TGMD-2 can be a useful tool for measurement of the gross motor skills of children with visual impairment in 7-10 years old. This tool can be used in clinics and treatment centers; it can also be used for research purposes.