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Power generation by high head water in a building using micro hydro turbine—a greener approach
2016
M. M. S. R. S., Bhargav | V., Ratna Kishore | S. P., Anbuudayasankar | K., Balaji
Demand for green energy production is arising all over the world. A lot of emphasis is laid in making the buildings green. Even a small amount of energy savings made contribute to saving the environment. In this study, an idea is proposed and studied to extract power from the high head water in the pipelines of a building. A building of height 15 m is considered for this study. Water flowing in the pipe has sufficient energy to run a micro hydro turbine. The feasibility of producing electrical energy from the energy of pipe water is found. The motivation is to find the feasibility of generating power using a low-cost turbine. The experimental setup consists of micro turbine of 135 mm diameter coupled to a 12-V DC generator; LEDs and resistors are employed to validate the results. The theoretical calculations were presented using the fundamental equations of fluid mechanics. The theoretical results are validated using experimental and numerical results using CFD simulation. In addition, exergy analysis has been carried out to quantify the irreversibilities during the process in the system.
显示更多 [+] 显示较少 [-]A comparative study of removal of fluoride from contaminated water using shale collected from different coal mines in India
2016
Biswas, Gargi | Dutta, Manjari | Dutta, Susmita | Adhikari, Kalyan
Low-cost water defluoridation technique is one of the most important issues throughout the world. In the present study, shale, a coal mine waste, is employed as novel and low-cost adsorbent to abate fluoride from simulated solution. Shale samples were collected from Mahabir colliery (MBS) and Sonepur Bazari colliery (SBS) of Raniganj coalfield in West Bengal, India, and used to remove fluoride. To increase the adsorption efficiency, shale samples were heat activated at a higher temperature and samples obtained at 550 °C are denoted as heat-activated Mahabir colliery shale (HAMBS₅₅₀) and heat-activated Sonepur Bazari colliery shale (HASBS₅₅₀), respectively. To prove the fluoride adsorption onto different shale samples and ascertain its mechanism, natural shale samples, heat-activated shale samples, and their fluoride-loaded forms were characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction study, and Fourier transform infrared spectroscopy. The effect of different parameters such as pH, adsorbent dose, size of particles, and initial concentration of fluoride was investigated during fluoride removal in a batch contactor. Lower pH shows better adsorption in batch study, but it is acidic in nature and not suitable for direct consumption. However, increase of pH of the solution from 3.2 to 6.8 and 7.2 during fluoride removal process with HAMBS₅₅₀ and HASBS₅₅₀, respectively, confirms the applicability of the treated water for domestic purposes. HAMBS₅₅₀ and HASBS₅₅₀ show maximum removal of 88.3 and 88.5 %, respectively, at initial fluoride concentration of 10 mg/L, pH 3, and adsorbent dose of 70 g/L.
显示更多 [+] 显示较少 [-]Ameliorative effect of synthetic γ-aminobutyric acid (GABA) on performance traits, antioxidant status and immune response in broiler exposed to cyclic heat stress
2016
The aim of this study was to find the effect of synthetic γ-aminobutyric acid (GABA) on the performance, antioxidant status, and immune response in broiler exposed to summer stress. A total of 400-day-old male broiler chickens (Ross 308) was randomly distributed into five treatments (5 replicates). One group served as a control (basal diet only) while the others were supplemented with GABA at the rate of 25 (GABA-25), 50 (GABA 50), 75 (GABA-75), and 100 (GABA-100) mg/kg feed. The experiment was continued for 35 days. Feed intake during the third week was significantly higher (P < 0.05) in GABA-75 and GABA-100, however, it increased significantly (P < 0.05) in GABA-100 during the fourth and fifth week. Overall mean feed intake was significantly (P < 0.05) high in GABA-75 and GABA-100. From the results, we found that body weight improved significantly (P < 0.05) in GABA-50 in week-3. During the fourth, fifth, and overall, body weight increased significantly (P < 0.05) in GABA-100. Significantly, high (P < 0.05) feed conversion ratio (FCR) was found in GABA-100 during the third, fourth, fifth, and on an overall basis. Mean Malondialdehyde (MDA) decreased significantly (P < 0.05) in GABA-100 while Paraoxonase (PON1) and Newcastle disease (ND) titer increased significantly (P < 0.05) in the same group. We concluded that performance traits, antioxidant status, and immune response improved in broiler supplemented 100 mg/kg GABA, exposed to cyclic heat stress.
显示更多 [+] 显示较少 [-]Earthworms, pesticides and sustainable agriculture: a review
2016
The aim of this review is to generate awareness and understand the importance of earthworms in sustainable agriculture and effect of pesticides on their action. The natural resources are finite and highly prone to degradation by the misuse of land and mismanagement of soil. The world is in utter need of a healthy ecosystem that provides with fertile soil, clean water, food and other natural resources. Anthropogenic activities have led to an increased contamination of land. The intensification of industrial and agricultural practices chiefly the utilization of pesticides has in almost every way made our natural resources concave. Earthworms help in a number of tasks that support many ecosystem services that favor agrosystem sustainability but are degraded by exhaustive practices such as the use of pesticides. The present review assesses the response of earthworm toward the pesticides and also evaluates the relationship between earthworm activity and plant growth. We strictly need to refresh and rethink on the policies and norms devised by us on sustainable ecology. In an equivalent way, the natural resources should be utilized and further, essential ways for betterment of present and future livelihood should be sought.
显示更多 [+] 显示较少 [-]Cd immobilization in a contaminated rice paddy by inorganic stabilizers of calcium hydroxide and silicon slag and by organic stabilizer of biochar
2016
A field experiment was conducted in a Cd-contaminated rice paddy field to evaluate the effect of inorganic and organic metal stabilizers on Cd mobility and rice uptake. A dose of inorganic stabilizer of calcium hydroxide (CH), silicon slag (SS), and wheat straw biochar (BC) was amended respectively to topsoil before rice transplanting. Rice production was managed with the same water regime and fertilization practices consistently between treatments including a control without amendment. Samples of topsoil and rice plant were collected at rice harvest to analyze the Cd mobility and uptake by rice. Without affecting rice grain yield, the stabilizers significantly decreased CaCl₂-extractable Cd in a range of 44 to 75 % compared to the control, corresponding to soil pH changes under the different treatments. Accordingly, Cd concentrations both in rice tissue and in rice grain were very significantly decreased under these treatments. The decrease in rice Cd uptake was correlated to the decrease in extractable Cd, which was again correlated to soil pH change under the different treatments, indicating a prevalent role of liming effect by the amendments. While applied at a large amount in a single year, organic stabilizer of BC decreased Cd extractability by up to 43 % and Cd rice uptake by up to 61 %, being the most effective on Cd immobilization. However, the long-term effect on soil health and potential tradeoff effects with different stabilizers deserve further field monitoring studies.
显示更多 [+] 显示较少 [-]Evidence for the importance of litter as a co-substrate for MCPA dissipation in an agricultural soil
2016
Barghūtī, ʻUmar al-Ṣāliḥ | Pagel, Holger | Enowashu, Esther | Devers, Marion | Martin-Laurent, Fabrice | Streck, Thilo | Kandeler, Ellen | Poll, Christian
Environmental controls of 2-methyl-4-chlorophenoxyacetic acid (MCPA) degradation are poorly understood. We investigated whether microbial MCPA degraders are stimulated by (maize) litter and whether this process depends on concentrations of MCPA and litter. In a microcosm experiment, different amounts of litter (0, 10 and 20 g kg⁻¹) were added to soils exposed to three levels of the herbicide (0, 5 and 30 mg kg⁻¹). The treated soils were incubated at 20 °C for 6 weeks, and samples were taken after 1, 3 and 6 weeks of incubation. In soils with 5 mg kg⁻¹ MCPA, about 50 % of the MCPA was dissipated within 1 week of the incubation. Almost complete dissipation of the herbicide had occurred by the end of the incubation with no differences between the three litter amendments. At the higher concentration (30 mg kg⁻¹), MCPA endured longer in the soil, with only 31 % of the initial amount being removed at the end of the experiment in the absence of litter. Litter addition greatly increased the dissipation rate with 70 and 80 % of the herbicide being dissipated in the 10 and 20 g kg⁻¹ litter treatments, respectively. Signs of toxic effects of MCPA on soil bacteria were observed from related phospholipid fatty acid (PLFA) analyses, while fungi showed higher tolerance to the increased MCPA levels. The abundance of bacterial tfdA genes in soil increased with the co-occurrence of litter and high MCPA concentration, indicating the importance of substrate availability in fostering MCPA-degrading bacteria and thereby improving the potential for removal of MCPA in the environment.
显示更多 [+] 显示较少 [-]Visible light photocatalytic antibacterial activity of Ni-doped and N-doped TiO2 on Staphylococcus aureus and Escherichia coli bacteria
2016
Ananpattarachai, Jirapat | Boonto, Yuphada | Kajitvichyanukul, Puangrat
The Ni-doped and N-doped TiO₂ nanoparticles were investigated for their antibacterial activities on Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacteria. Their morphological features and characteristics such as particle size, surface area, and visible light absorbing capacity were compared and discussed. Scanning electron microscopy, X-ray diffraction, and UV–visible spectrophotometry were used to characterize both materials. The inactivation of E. coli (as an example of Gram-negative bacteria) and S. aureus (as an example of Gram-positive bacteria) with Ni-doped and N-doped TiO₂ was investigated in the absence and presence of visible light. Antibacterial activity tests were conducted using undoped, Ni-doped, and N-doped TiO₂. The N-doped TiO₂ nanoparticles show higher antibacterial activity than Ni-doped TiO₂. The band gap narrowing of N-doped TiO₂ can induce more visible light absorption and leads to the superb antibacterial properties of this material. The complete inactivation time for E. coli at an initial cell concentration of 2.7 × 10⁴ CFU/mL was 420 min which is longer than the 360 min required for S. aureus inactivation. The rate of inactivation of S. aureus using the doped TiO₂ nanoparticles in the presence of visible light is greater than that of E. coli. The median lethal dose (LD50) values of S. aureus and E. coli by antibacterial activity under an 18-W visible light intensity were 80 and 350 mg/ml for N-doped TiO₂, respectively.
显示更多 [+] 显示较少 [-]Short-term arsenic exposure reduces diatom cell size in biofilm communities
2016
Barral-Fraga, Laura | Morin, Soizic | Rovira, Marona D. M. | Urrea, Gemma | Magellan, Kit | Guasch, Helena
Arsenic (As) pollution in water has important impacts for human and ecosystem health. In freshwaters, arsenate (Asⱽ) can be taken up by microalgae due to its similarity with phosphate molecules, its toxicity being aggravated under phosphate depletion. An experiment combining ecological and ecotoxicological descriptors was conducted to investigate the effects of Asⱽ (130 μg L⁻¹ over 13 days) on the structure and function of fluvial biofilm under phosphate-limiting conditions. We further incorporated fish (Gambusia holbrooki) into our experimental system, expecting fish to provide more available phosphate for algae and, consequently, protecting algae against As toxicity. However, this protection role was not fully achieved. Arsenic inhibited algal growth and productivity but not bacteria. The diatom community was clearly affected showing a strong reduction in cell biovolume; selection for tolerant species, in particular Achnanthidium minutissimum; and a reduction in species richness. Our results have important implications for risk assessment, as the experimental As concentration used was lower than acute toxicity criteria established by the USEPA.
显示更多 [+] 显示较少 [-]Design of a toxicity biosensor based on Aliivibrio fischeri entrapped in a disposable card
2016
Jouanneau, Sulivan | Durand-Thouand, Marie-José | Thouand, Gérald
The degradation of the marine environment is a subject of concern for the European authorities primarily because of its contamination by hydrocarbons. The traditional methods (ISO 11348 standard) of general toxicity assessment are unsuitable in a context of in situ monitoring, such as seaports or bathing zones. Consequently, to address this issue, bacterial biosensors appear to be pertinent tools. This article presents the design of an innovative bioluminescent biosensor dedicated to in situ toxicity monitoring. This biosensor is based on the entrapment of the wild marine bioluminescent bacterial strain Aliivibrio fischeri ATCC® 49387™ in an agarose matrix within a disposable card. A pre-study was needed to select the most biological parameters. In particular, the regenerating medium’s composition and the hydrogel concentration needed for the bacterial entrapment (mechanical resistance) were optimized. Based on these data, the ability of the bacterial reporter to assess the sample toxicity was demonstrated using naphthalene as a chemical model. The biosensor’s results show a lower sensitivity to naphthalene (EC₅₀ = 95 mg/L) compared with the results obtained using the reference method (EC₅₀ = 43 mg/L). With this architecture, the biosensor is an interesting compromise among low maintenance, ease of use, appropriate sensitivity, relatively low cost and the ability to control online toxicity.
显示更多 [+] 显示较少 [-]Coupled urbanization and agricultural ecosystem services in Guanzhong-Tianshui Economic Zone
2016
Zhou, Z. X. | Li, J. | Zhang, W.
Ecosystems offer material and environmental support for human habitation and development in those areas of the earth where people choose to live. However, urbanization is an inexorable trend of human social development and threatens the health of those ecosystems inhabited by humans. This study calculates the values of NPP (net primary productivity), carbon sequestration, water interception, soil conservation, and agricultural production in the Guanzhong-Tianshui Economic Zone. At the same time, we combined DMSP/OLS (Defense Meteorological Satellite Program Operational Line Scanner) night lights remote sensing data and statistical data to analyze the level of urbanization. Quantitative analysis was performed on the interactions between the ecosystem service functions and urbanization based on the calculations of their coupled coordination degrees. The results were the following: (1) The values of NPP, carbon sequestration, and agricultural production showed a trend of increase. However, water interception decreased before increasing, while soil conservation showed the reverse trend; (2) Urbanization levels in the Guanzhong-Tianshui Economic Zone for the last 10 years have proceeded at a fast pace with comprehensive promotion; and (3) Coupled and coupled coordination degrees between urbanization and ecosystem services show increasing trends. This research can provide a theoretical basis for the region’s rapid economic development in the balance.
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