پسماندهای الکترونیکی و الکتریکی انواعی از پسماندهای ویژه می‌باشند که قطعات اصلی آن‌ها شامل خازن، ترانزیستور، آی.سی، مدارات الکترونیکی، قطعات کاتدی و آندی بوده و دارای خاصیت سمیت، بیماری‌زایی و پایایی در محیط پیرامون و حتی در پیکره جانداران، خورندگی تاسیسات و تجهیزات و مشابه آن می‌باشند.بر این اساس، هدف از این تحقیق بررسی و شناسایی عوامل موثر در آزادسازی این فلزات و اختصاصاً عنصر کادمیوم در محیط پیرامون می‌باشد. جهت بررسی این موضوع تاثیر عوامل مختلف مانند دما، pH، ترکیبات هامیک و زمان بر روی آزادسازی عنصر کادمیوم از اینگونه پسماندها به محیط‌های آبی مورد مطالعه قرار گرفته است. بدین منظور قطعات انتخابی آنالیز گردیده و مورد بررسی قرار گرفتند. نتایج بیانگر آن بوده است که در محیط آبی،‌ میزان نفوذ کادمیوم در pH بسیار اسیدی و بسیار قلیایی میزان آزادسازی افزایش می‌یابد. همچنین؛ در محیط آبی، افزایش دما سبب افزایش میزان نفوذ عنصر کادمیوم در محیط می‌گردد و اثر پارامتر زمان تماس نیز متناسب با تغییرات pH متغیر می‌باشد. پرونده مقاله

the study aimed to validate the proposed model for environmental policy in the country to decrease environmental pollution in form of a network approach. This descriptive-analytical and cross-sectional study was carried out through survey approach. The statistical population of the study consisted of experts and policy makers in the field of environment who had environmental planning and policy making experience at national and regional level. In this research, Structural Equation Method (SEM) was used for analysis. The results showed good and acceptable fit regarding two indices of TLI and CFI (0.93). On the other hand, the number obtained in terms of the GFI index also indicates the relative fitness of the model (0.86). Also, the acceptability of the model is confirmed regarding PNFI and PGFI indices through the obtained numbers which were 0.78 and 0.84, respectively. The achieved value of the RMSEA index (0.073) also indicates that the model is acceptable. Finally, the results of factor analysis showed that this model was fit and all the numbers and parameters were significant. These facts confirm the acceptability and excellent fitness of the model. In sum, among the three main factors related to the data of the network-based environmental policy system, the “intervening conditions” with the factor loading of 0.96 was the best predictors. Out of the 17 measured items, the component of "national maturity" had the highest factor loading and the component of "Eleventh State Environmental Policies" had the lowest factor loading. پرونده مقاله

The purpose of this study is to measure the sound level in bodybuilding clubs in Mashhad with the approach of maintaining the health of athletes. The metropolis of Mashhad, the capital of Khorasan Razavi province, is located in northeastern Iran. Fifteen bodybuilding clubs were randomly selected by networking method. The sound level in the clubs was measured in level A and as an equivalent level by the portable device and software Decibel X version 2019 and was compared with the sound standard (OSHA-90 dBA). Measurements were made in the morning and evening. The parameters of sound pressure level (SPL), mean sound level (LP) ̅continuous sound equivalent level (Leq) and individual daily dose of LAEp, d were calculated. The lowest sound pressure level in the morning was 76.5 decibels and the highest pressure level in the evening was 99.4 decibels. There was a direct relationship between sound pressure level and athletes' time in the club. The average sound level in sports clubs is equal to 87.6 dB and the level is equal to 90.61 and the daily individual dose of LEp, d athlete in the club is equal to 84.58 dB. The permissible duration of exposure to noise for athletes was estimated at 1 hour and 40 minutes. In the gymnasiums of Mashhad, athletes are exposed to high noise pollution and the possibility of physical and mental injuries is high. پرونده مقاله

Lightweight expanded clay aggregate due to its physical and chemical properties; it can increase the process of adsorption and ion exchange.In this study, the efficiency 2 types of Lightweight Expanded Clay Aggregate in reducing the amount of COD, BOD, TSS, nitrate and phosphate in dairy industry wastewater were investigated and the impact of different factors such as adsorbent dosage, mixing speed and mixing time were studied. The results showed that the efficiency of COD reduction of wastewater after touch with the granular type after 20 h is 65.9%. TSS and BOD have also been greatly reduced. Also the use of powder type, the highest removal efficiency was 31.81%, mixing speed 100 rpm, mixing time 20h, and adsorbent dosage 10 gr/l in addition; increasing the rate of mixing speed increases the amount of nitrate absorption. The most effective nitrate removal is 63.87% which was at mixed speed 200 rpm and absorbent dose 4 g/l. Results show that, the mixing speed has little effect on the absorption of phosphate. So, after 30 minutes, even with increasing mixing speed for doses 2 & 4 g/l, the reduction efficiency also decreases the change in absorbent dose from 1 g/l to 4 g/l was virtually unaffected. Increased mixing speed is due to better distribution of nitrate and phosphate molecules in the solution and their contact with adsorbent increased the absorption rate. According to the results, the LECA granular has more ability to remove the COD. پرونده مقاله