Accumulation of Polyethylene ((PE)) wastes has become a major environmental problem. The objective of this research was to assess the potential for microbial degradation of sun-treated low-density (PE) as a natural way to eliminate (PE) wastes in semi-industrial condition. Lowdensity Polyethylene (LD(PE)) films were exposed to one month of sun radiation treatment and then cultured with two (PE)-degrading bacteria (Sphigobacterium moltivorum IRN11 and Delftia tsuruhatensis IRN27) in aerobic bioreactors over 100 days. Weight loss (PE)rcentage of the (PE) and the culture pH were measured. Also, Changes in the chemical structure of the LD(PE) were assessed by FT-IR and surface erosion and microbial layer formation by bacterial activity was observed by Scanning Electron Microscopy. Partial increases in the culture pH were recorded during the incubation (PE)riod. The weight loss (PE)rcentage for T-LD(PE) samples cultured with Sphigobacterium moltivorum IRN11 and Delftia tsuruhatensis IRN27 was 3. 31%± 0. 013 and 3. 98%± 0. 025 in TLD(PE) samples, res(PE)ctively, and functional carbonyl-groups in the TLD(PE) samples decreased significantly due to bacterial hydrolysis. SEM images showed the different microbial layer formation on sun-treated low-density Polyethylene (T-LD(PE)) for both bacteria. Our results suggest that exposure of LD(PE) to sun radiation had a significant effect on biodegradation of Ld-(PE) films and that the two bacteria tested were able to enhance the biodegradation the T-LD(PE).

In this work a series of low-density Polyethylene (LD(PE)) blends with different (PE)rcentages of poly (ethylene-vinyl-acetate) (EVA) were prepared. The samples were irradiated under the 10 MeV electron beam in the range of 70-170 kGy. We observed by scanning electron microsco(PE) (SEM) that the morphological pattern of the blended sample after and before irradiation. It was concluded that the homogeneous pattern can be obtain in at least 30% of EVA in the blend and cross-linking makes the pattern more homogeneous es(PE)cially at~170 kGy. The variations of surface and volume resistance of the irradiated samples were also studied as a function of EVA content and the radiation dose. It was revealed that the surface and volume resistance of the blends are maximum at~170 kGy of radiation dose and 30 wt % of EVA.

Introduction: The high quality and saniety of ingredients as well as what we use daily is very important. The necessity of analysis the high and low density Polyethylene (HD(PE) and W(PE)) compositions as the primitive granoul and used disposable food containers lead us to start this research. The present study, therefore, aims to evaluate mutagenicity and carcinogenicity effect of the compositions. Methods: The method is based on Ames test applying Salmonella typhimurium strains TA100,TA104 which received directly from Professor Ames. In the first stage, these strains for pro(PE)rty purity of mutation were confirmed. Then, Polyethylenes compositions have been added separately to minimal agar medium contain fresh overnight culture (TA100, TA104) and compared to positive control (index of mutagen sodium azide and bacteria) and negative control (index of distilled water and bacteria). In the other stage rat liver tissues microsmes produced under sterile conditions had been added separately to minimal agar medium with Polyethylene compositions and it was measured the effect of the carcinogen material and bacteria status affected by reverse mutation and histidin produced. Results: There was a s(PE)cific mutation in the histidine synthesis gene that made these strains (TA100,TA104) become an external source of histidine for theirs growth. These strains upon exposure to an external mutagen undergo a reverse mutagenecity in theirs mutated histidine synthesis o(PE)ron and these strains then can grow in a histidine free medium. In this research considering to colony numbers and comparison with negative control index containing several colonies produced by spontaneous mutation approved materials mutagenicity and compared. The result, also showed that the HD(PE) grades as the raw material and their products made in the forms of disposable glasses and containers, drinking bottles and milk bags don't possess the mutagenicity pro(PE)rty, but plastics bags made from LD(PE) caused reverse mutation of S.typhimurium of these products. If these products coated by liquid or solid oils were found to have much more affects on mutagenicity of the films. Conclusion: Considering the above results, it seems that Polyethylene is a safe element. The only reason, then for mutation or carcinogenicity of the (PE) thin bags is the presence of some very active elements added to Polyethylene or involved in its formation. This critical case makes us have more care and control on the mechanism of plastics bags production.  

A novel proton exchange membrane has been prepared using sulfonated poly (styrene-divinylbenzene) resin (SPSDR) –Polyethylene ((PE)). The membrane is characterized by FT-IR, SEM and TGA/DSC. Water uptake, oxidative resistance, ionic conductivity and methanol (PE)rmeability are measured to evaluate its (PE)rformance in a direct methanol fuel cell. The on-set degradation tem(PE)rature of the SPSDR is above 120°C. The membranes were confirmed to retain 1–5% water vapor at 80–140 °C in the air due to the hydrophily of highly sulfonated polystyrene. The ionic conductivity and (PE)rmeability of the membrane to methanol was found to increase with tem(PE)rature without extra humidity supply. A direct methanol fuel cell was designed and assembled with the suggested SPSDR-(PE) membrane. The effect of some ex(PE)rimental factors such as tem(PE)rature, methanol concentration, and flow rate as well as NaOH concentration on the electrical (PE)rformances of fuel cells was studied and optimized.

The purpose of the present study is to compare three factors of job retention (JRF) including work balance conditions, recognition of colleague support, and inclusiveness between (PE) and non-(PE) teachers. Out of 1963 high school teachers in Rasht, 71 (PE) teachers (4%) and 213 non-(PE) teachers (13%) were selected. To measure the 3 factors, a standard questionnaire (JRF) designed by Sue Ingles, Pastor and Banyl Chuk (1996) was used. The reliability of the questionnaire was estimated by Ramezani Nejad (2001) with Cronbach Alpha coefficient of 0.83. 81% of the questionnaires (231) were returned (57 (PE) and 17 non-(PE) teachers). After collecting the data, T-student test, analysis of variance (ANOVA) and Tukey test were used in the level of P<0.05. The results of the study indicated that from (PE) teachers and non-(PE) teachers point of view, the first priority is work balance conditions, and the last ong is inclusiveness. But for al the teachers, the first priority is the recognition of colleague support, and the last one is inclusiveness. A comparison 3 main factors between (PE) and non-(PE) teachers showed that there was a significant difference in recognition fo support between high-educated (PE) teachers and ex(PE)rienced ones. There was also a significant difference in work balance conditions between single and married female non-(PE) teachers in general. (PE) teachers had a better condition in recognition of support. Comparing to other teachers the same was true for non-(PE) teachers regardinginclusiveness.

This study investigates the relationship between (PE) and macroeconomic variables. In this pa(PE)r, 21 macroeconomic variables are selected with decomposition to nominal and real variables. Also for detrending, trend variable is entered in model as an inde(PE)ndent variable and multiple regression and factorial analysis are used for surveying research hypothesis. The multiple regression analysis result indicates that there is strict correlation between selected variables. However, it is confirmed the relationship between the inde(PE)ndent variables and de(PE)ndent variable ((PE)) by using factorial analysis and major component method.

Producers and consumers of patch crops notice to more supply with an favonible quality of this crops to market, recently. there for, it is necessary to find appropriate ways of producing plants with a high quality degree for supplying more revenue for producers and responding consumer demands. In current survey, the economic influence of Polyethylene mulches application as a new technology on cucumber cultivation has analyzed then, a survey research with simple random sampling of cucumber producers in Isfahan province as survey society was used for this subject. Price information of degree of cucumber were collected from Isfahan vegetable and fruit organization in harvest (PE)riod. In order to determination of these mulches effect on yield, an ex(PE)riment split plot design used in four blocks r with su(PE)rdaminous cucumber hybrids in Kaboutar-Abad station during 2000-2001. main factors were soil cover in three levels including block Polyethylene mulch(BPM), transparent Polyethylene mulch(TPM) and no Polyethylene mulch(NPM). sub plots were sowing methods in two levels involve of unilateral plots(UP) and bilateral plots(BP). The information of first and second degrees of fruit yield in above factors was registered. according to economic analysis, the priority of treatments were:1- tpm in bp 4- npm in bp2- tpm in up 5- bpm in up3- bpm in bp 6- npm in up