نتایج جستجو برای: degradation of environment
تعداد نتایج: 21204425 فیلتر نتایج به سال:
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...
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...
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...
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...
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...
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...
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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