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排序方式: 共有1724条查询结果,搜索用时 359 毫秒
721.
Vineet Kumar Praveen Guleria Surinder Kumar Mehta 《Environmental Chemistry Letters》2017,15(2):165-177
Food toxins are produced as defense tools by microorganisms that use nutrients for their growth. Microorganisms thus spoil food, taste and can infect humans, sometimes leading to death. Food adulteration and brand protection are also major issues in the food industry. Here we review the use of nanomaterials for sensing food quality. Nanosensors can detect pathogenic bacteria, food-contaminating toxins, adulterant, vitamins, dyes, fertilizers, pesticides, taste and smell. Food freshness can be monitored using time–temperature and oxygen indicators. Product authenticity and brand protection can be assessed using invisible nanobarcodes. Overall, nanosensors with unique properties are improving food security. 相似文献
722.
Dhananjay Kumar J. P. Gaur 《Environmental science and pollution research international》2014,21(17):10279-10285
The present study explores the tolerance and metal removal response of a well-developed 2-week-old Phormidium mat after long-term exposure to Cu2+-enriched medium. Cu2+ enrichment inhibited increase in mat biomass in a concentration-dependent manner. Mat area and the number of entrapped air bubbles decreased as Cu2+ concentration increased in the medium. Decrease in number of air bubbles obviously reflects the adverse effect of Cu2+ on photosynthetic performance of the mat. Metal enrichment did not substantially alter the amount of pigments, such as chlorophyll a, chlorophyll b, carotenoids, and phycocyanin, in the mat. Enhancement of Cu2+ concentration in the medium led to changes in species composition of the test mat; however, Phormidium bigranulatum always remained the dominant organism. Relative share of green algae and some cyanobacterial taxa, namely, Lyngbya sp. and Oscillatoria tenuis, in the mat were increased by Cu2+ enrichment. The mat successfully removed 80 to 94 % Cu2+ from the growth medium containing 10 to 100 μM Cu2+. Extracellular polysaccharides, whose share increased in the mat community after metal addition, seem to have contributed substantially to metal binding by the mat biomass. 相似文献
723.
Kumar Peeyush Mishra Sapna Kumar Atul Kumar Sanjeev Prasad Chandra Shekhar 《Environmental science and pollution research international》2017,24(27):21948-21959
Environmental Science and Pollution Research - Contamination of environment and food from the prevalent spores and mycotoxins of Aspergillus niger has led to several diseases in humans and other... 相似文献
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Ajay Batish Tejinder P Singh 《International journal of occupational safety and ergonomics》2008,14(2):223-235
This paper describes an assessment tool for analysing material handling tasks and its application for material handling tasks prevalent in engine bearing industry. After a close observation of material handling tasks spread over many days, a list of tasks and parameters/variables affecting those tasks was made. Ergonomic conditions present in these tasks and their deficiencies were then identified and on the basis of the relationships between the tasks and their affinities, categories were developed. Using the data of those categories and various conditions and parameters, an assessment tool called MHAC (material handling assessment chart) was developed. 相似文献
728.
R. Uma Rani S. Adish Kumar S. Kaliappan IckTae Yeom J. Rajesh Banu 《Waste management (New York, N.Y.)》2013,33(5):1119-1127
Microwave (MW) irradiation is one of the new and possible methods used for pretreating the sludge. Following its use in different fields, this MW irradiation method has proved to be more appropriate in the field of environmental research. In this paper, we focused on the effects of MW irradiation at different intensities on solubilization, biodegradation and anaerobic digestion of sludge from the dairy sludge. The changes in the soluble fractions of the organic matter, the biogas yield, the methane content in the biogas were used as control parameters for evaluating the efficiency of the MW pretreatment. Additionally, the energetic efficiency was also examined. In terms of an energetic aspect, the most economical pretreatment of sludge was at 70% intensity for 12 min irradiation time. At this, COD solubilization, SS reduction and biogas production were found to be 18.6%, 14% and 35% higher than the control, respectively. Not only the increase in biogas production was investigated, excluding protein and carbohydrate hydrolysis was also performed successfully by this microwave pretreatment even at low irradiation energy input. Also, experiments were carried out in semi continuous anaerobic digesters, with 3.5 L working volume. Combining microwave pretreatment with anaerobic digestion led to 67%, 64% and 57% of SS reduction, VS reduction and biogas production higher than the control, respectively. 相似文献
729.
S. Ahmed R. Kumar J. E. Helt 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1328-1333
A mathematical model has been developed to study the thermal and chemical processes occurring In a municipal solid waste mass combustor. Treating the solids feed as a mixture of pseudo-components, the model determines the Interrelationships between the solids feed rate, grate travel rate and length, amounts and distributions of primary and secondary air, extent of solids burn out, and the bed and flame temperatures. The model Incorporates the kinetics of pyrolysis of solids and simulates heat and mass transfer within the bed. The temperature and mass flow profiles generated show that much of the grate Is taken up by the heatup and burnout zones. The heatup zone can be reduced by distributing the primary air to maintain minimal air flow In that region, thereby permitting rapid heatup. Increasing the solids feed rate and adjusting the air flow distributions can reduce the length of the burnout zone. The computer program, available on both PCs and mainframe, can be used for different MSW Incinerator dimensions and feed parameters to Investigate the effects of the control variables and optimize the desired output characteristics, e.g., maximize solids throughput. 相似文献
730.
Vishnu Vardhan Kanuri Rita Saha Shiv Pratap Raghuvanshi Ashwani Kumar Singh Bipasha D. Chakraborty V. Kiran Kumar 《Chemistry and Ecology》2020,36(1):30-47
ABSTRACTTo understand the temporal variations of the physicochemical characteristics of the Bhagirathi-Hooghly River (BHR), three locations representing three districts of West Bengal were selected. The material fluxes from 34 drains during pre-monsoon season was quantified. The analysis of variance (ANOVA) revealed that no significant spatial variations were observed for the physicochemical parameters, whereas seasonal variations were significant. The mean discharge was found to be highest (247.2?×?103?m3?d?1) in the midstream drains. Highest mean concentrations of dissolved oxygen (DO) (7.35?mg?L?1) and nitrate (0.81?mg?L ?1) were observed during the post-monsoon season followed by the monsoon and pre-monsoon. According to the BIS, WHO and the European standard of water quality (pH, 6.5–8.5; Nitrate, 0–2.5?mg?L?1;DO, ≥5?mg?L?1), the results of the respective parameters revealed the BHR system is maintained at high to good water quality, meaning that the BHR system is slightly altered from its pristine environment. The mean concentrations of biological and chemical oxygen demands were found to be high during the monsoon season, revealing that a large quantity of refractory organic matter is transported to the eastern Bay of Bengal from the Ganges. 相似文献