Search results for "Environment"
showing 10 items of 28487 documents
Guano-related phosphate-rich minerals in European caves
2019
International audience; Guano is a typical deposit found in caves derived from the excretions of bats and in minor cases of birds. These organic deposits decompose and form a series of acid fluids and gases that can interact with the minerals, sediments, and rocks present in the cave. Over sixty phosphates are known and described from caves, but guano decay also often leads to the formation of nitrates and sulfates. In this study twenty-two European caves were investigated for their guano-related secondary minerals. Using various analytical techniques, seventeen phosphates, along with one sulfate (gypsum), were recognized as secondary products of guano decay. Among those minerals, some are …
Environmental Organic Photochemistry: Advances and Perspectives
2013
This review is a survey of recent advances in environment related aspects of organic photochemistry. Besides presenting gen- eral concepts, the manuscript is mainly focused on the photoreactivity of natural organic matter, and on the photochemistry of anthropo- genic substances under natural light irradiation.
Degradation of Lincomycin in aqueous medium: coupling of solar photocatalysis and membrane separation
2005
Abstract The photocatalytic oxidation of a common antibiotic, the lincomycin was carried out in aqueous suspensions of polycrystalline TiO 2 Degussa P25 irradiated by sunlight. In order to improve the performance of the lincomycin degradation a hybrid system consisting of a solar photoreactor with the photocatalyst in suspension coupled with a membrane module, used to confine both photocatalyst and pollutants in the reaction environment, was tested. A preliminary study was carried out in order to determine some kinetics parameters of the drug photodegradation. The influence of initial substrate concentration on the lincomycin photooxidation rate was investigated. The photooxidation rate fol…
Chronic toxicity of diazinon todaphnia magna:Effects on survival, reproduction and growth
1995
The sublethal effect of 0.15, 0.18, 0.22, 0.25 and 0.30 μg/L diazinon on the survival, reproduction and growth of D. magna was monitored for 21 days. Neonates (≤ 24 h) were obtained from the stock cultures and raised individually in 50 mL glass beakers. All daphnids were transfered every other day to a new beaker containing fresh medium, food and the appropriate pesticide concentration. The animals were maintained in an environmental chamber at 22±1°C on a 12L: 12D photoperiod and were fed daily on 5 x 105 cell/mL of the green algae Nannochloris oculata. The parameters used to determine the effect of the pesticide on reproduction were: mean total young per female, mean brood size, mean numb…
Thin Film CIGS Solar Cells, Photovoltaic Modules, and the Problems of Modeling
2013
Starting from the results regarding a nonvacuum technique to fabricate CIGS thin films for solar cells by means of single-step electrodeposition, we focus on the methodological problems of modeling at cell structure and photovoltaic module levels. As a matter of fact, electrodeposition is known as a practical alternative to costly vacuum-based technologies for semiconductor processing in the photovoltaic device sector, but it can lead to quite different structural and electrical properties. For this reason, a greater effort is required to ensure that the perspectives of the electrical engineer and the material scientist are given an opportunity for a closer comparison and a common language.…
Experimental test of the performances of a photovoltaic modules model
2015
In this paper, a measurement-based modeling technique for PV panels oriented to power electronics design is proposed. The proposed modelling approach aims at an accurate modeling of the whole PV curve and not only around a few remarkable points. The proposed approach is based on an experimental characterization of the module under test. In fact, the incompleteness of manufacturers' data and the knowledge of physical parameters are the main source of inaccuracy in existing modelling approaches. The proposed approach is applied to a four lumped parameters model of a Conergy E215P solar module. Tests are performed under natural light. The parameter identification procedure is described in deta…
Ground-Mounted Photovoltaic and Crop Cultivation: A Comparative Analysis
2022
Human civilization depends on energy sources, mainly fossil fuels. An increase in the prices of fossil fuels and their exhaustibility limit economic growth. Carbon dioxide emission causes global environmental problems. Global crises (including COVID-19) have sharpened food and energy supply problems. The decentralized energy supply systems as well as the expedition of the application of renewable energy may solve these challenges. The economic shift to renewable power generation intensifies the competition between food crop production and green energy for land. This paper applied an open-source spatial-based model to quantify the solar power generation (the ground-mounted photovoltaic panel…
Laser Beam Induced Current measurements on Dye Sensitized Solar Cells and thin film CIG(S,SE)2 modules
2017
Calculating the efficiency of a solar cell depends on a precise knowledge of its area. Indeed, the photoresponse uniformity is essential to improve the manufacturing process. In this work we report on Laser Beam Induced Current measurements performed on CIG(S,Se)2 modules and Dye Sensitized Solar Cells. These measurements, performed via a green and a red HeNe lasers both operating at an optical irradiance of 1 Sun, allowed to obtain an accurate photoresponse map of the specimens and highlighted the non-uniformities with a spatial resolution of 400 μm and 80 μm, respectively.
Subjective stress, objective heart rate variability-based stress, and recovery on workdays among overweight and psychologically distressed individual…
2015
Background: The present study aimed to investigate how subjective self-reported stress is associated with objective heart rate variability (HRV)-based stress and recovery on workdays. Another aim was to investigate how physical activity (PA), body composition, and age are associated with subjective stress, objective stress, and recovery. Methods: Working-age participants (n = 221; 185 women, 36 men) in this cross-sectional study were overweight (body mass index, 25.3-40.1 kg/m(2)) and psychologically distressed (>= 3/12 points on the General Health Questionnaire). Objective stress and recovery were based on HRV recordings over 1-3 workdays. Subjective stress was assessed by the Perceived St…
Physical and Quality of Life Changes in Elderly Patients after Laparoscopic Surgery for Colorectal Cancer—A Prospective Cohort Study
2022
Background—The incidence of colorectal cancer is increasing among elderly people, where postoperative complications are frequent. Methods—We evaluated postoperative physical and quality of life changes in elderly patients undergoing laparoscopic surgery for colorectal cancer. A prospective cohort study was performed in 31 colorectal cancer patients ≥60 years who were scheduled for laparoscopic surgery due to colorectal cancer. Outcomes were measured one month preoperative (T1), three days postoperative (T2) and one month postoperative (T3). Results—The largest early postoperative (from T1 to T2) declines were observed for isometric knee extension strength (33.1%), 30 s …