نتایج جستجو برای: degradation of environment

تعداد نتایج: 21204425  

2012
M. Yasin Ulukus Jeffrey P. Kharoufeh Lisa M. Maillart

We examine the problem of optimally maintaining a stochastically degrading system using preventive and reactive replacements. The system’s rate of degradation is modulated by an exogenous stochastic environment process, and the system fails when its cumulative degradation level first reaches a fixed deterministic threshold. The objective is to minimize the total expected discounted cost of prev...

اصیلیان, حسن, جنیدی جعفری, احمد, خوانین, علی, دارابی, المیرا, رضایی, عباس, غلام نیا, رضا,

Background and Objective: Polychlorinated biphenyls (PCBs) are toxic, persistent, bio-accumulate and pose a risk of causing adverse effects on human health and to the environment. PCB compounds exert varios impacts on human depending upon age, route of entry, intensity and frequency of exposure. This study was conducted to determine the effect of UV-C, hydrogen peroxide and solvent on the photo...

Ahmad Jonidi, Ali Khavanin, Ardalan Soleimanian, Babak Eshrati, Hasan Asilian, Reza Tajik,

Background: Poly chlorinated biphenyls (PCBS) are the groups of organic chemical material and toxic, persistent, bio accumulate and pose a risk of causing adverse effects to human health and the environment. PCB compounds are caused the different health effects in human depending of age, sex, route of entry, intensity and frequency exposure. This study was conducted to determine the effect of...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1390

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

Flourene and phenanthrene are organic compounds with high hydrophobicity and toxicity. Being recalcitrant in nature they are accumulating in the environment at an alarming concentration, posing serious threat to living beings. Thus in the present study, microorganisms were screened for their ability to degrade these contaminants at high concentrations in least period of time. Two out of fifteen...

Journal: Pollution 2019

Flourene and phenanthrene are organic compounds with high hydrophobicity and toxicity. Being recalcitrant in nature they are accumulating in the environment at an alarming concentration, posing serious threat to living beings. Thus in the present study, microorganisms were screened for their ability to degrade these contaminants at high concentrations in least period of time. Two out of fifteen...

دیانتی تیلکی, رمضانعلی , رستمعلی, احسان, ززولی, محمدعلی , علم قلیلو, مهدیه , یزدانی, جمشید ,

Background and purpose: Chrophenols represent one of the most abundant toxic compounds of industrial which are resistant to biodegradation and persist in the environment for long time. Sunlight is the source of many photochemical reactions. The present study aimed to determine degradation of 4-chlrophenol as persistent organic compound by sunlight in the presence of zinc oxide as a catalyst. M...

Journal: :Bioresource Technology Reports 2022

Composting is an essential biochemical process to pre-treat lignocellulosic biomass (e.g., wheat straw) generate nutritious substrate for industrial Agaricus bisporus production. During composting numerous microbes target (hemi-)cellulose using their enzymatic machinery, while lignin has been assumed remain unaffected. This research aimed unravel the chemical and microbial changes during a 4-da...

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