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排序方式: 共有362条查询结果,搜索用时 15 毫秒
41.
Sarat K. Swain Gyanaranjan Prusty Ashish S. Ray Lingaraj Behera 《Journal of Experimental Nanoscience》2014,9(3):240-248
Poly(methyl methacrylate)/expanded graphite (PMMA/EG) composites were prepared by the incorporation of EG in various proportions (1%, 2%, 3%, 4% and 5%) with PMMA by in situ polymerisation technique. The polymer composites were characterised by ultraviolet–visible (UV–vis) and Fourier transform infra-red spectroscopies. The structural property of PMMA/EG nanocomposites was studied by X-ray diffraction. The scanning electron microscopy and transmission electron microscopy of synthesised composites were taken in order to study their morphological properties. The conductivity of composites was measured as function of EG concentration. It was found that conductivity of composites gradually increased with the increase in EG loading. Oxygen permeability of PMMA/EG nanocomposites was calculated and it was found that the property was reduced substantially with rise of EG proportion. The thermal stability of PMMA/EG nanocomposites was improved by dispersion of EG with PMMA matrix. 相似文献
42.
The 0.5(BiGd0.05Fe0.95O3)-0.5(PbZrO3) composite was synthesized by means of a high temperature solid-state reaction technique using high purity ingredients. Preliminary X-ray structural analysis confirms the formation of the composite. The dielectric constant and loss tangent have been studied. The impedance parameters have been measured using an impedance analyzer in a wide range of frequency (102–106 Hz) at different temperatures. The Nyquist plot suggests the contribution of bulk effect only and the bulk resistance decreases with a rise in temperature. Electrical impedance confirms the presence of grain effect and hopping mechanism in the electrical transport of the material. The dc conductivity increases with a rise of temperature. The frequency variation of ac conductivity shows that the compound obeys Jonscher’s universal power law and from Jonscher’s power law fit confirms the Small Polaron (SP) tunneling effect. Temperature dependence of dc and ac conductivity indicates that electrical conduction in the material is a thermally activated process. 相似文献
43.
Occurrence and removal efficiencies of 20 pharmaceuticals and personal care products (PPCPs) including antibiotics, hormones, and several other miscellaneous pharmaceuticals (analgesics, antiepileptics, antilipidemics, antihypertensives, antiseptics, and stimulants) were investigated in five wastewater treatment plants (WWTPs) of Ulsan, the largest industrial city of Korea. The compounds were extracted from wastewater samples by solid-phase extraction (SPE) and analyzed by High-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The results showed that acetaminophen, atenolol and lincomycin were the main individual pollutants usually found in concentrations over 10 μg/L in the sewage influent. In the WWTPs, the concentrations of analgesic acetaminophen, stimulant caffeine, hormones estriol and estradiol decreased by over 99%. On the contrary, the antibiotic sulfamethazine, the antihypertensive metoprolol, and the antiepileptic carbamazepine exhibited removal efficiencies below 30%. Particularly, removal of antibiotics was observed to vary between − 11.2 and 69%. In the primary treatment (physico-chemical processes), the removal of pharmaceuticals was insignificant (up to 28%) and removal of majority of the pharmaceuticals occurred during the secondary treatment (biological processes). The compounds lincomycin, carbamazepine, atenolol, metoprolol, and triclosan showed better removal in WWTPs employing modified activated sludge process with co-existence of anoxic-oxic condition. Further investigation into the design and operational aspects of the biological processes is warranted for the efficient removal of PPCPs, particularly antibiotics, to secure healthy water resource in the receiving downstream, thereby ensuring a sustainable water cycle management. 相似文献
44.
Hydrogeochemistry,Elemental Flux,and Quality Assessment of Mine Water in the Pootkee-Balihari Mining Area,Jharia Coalfield,India 总被引:3,自引:0,他引:3
Abhay?Kumar?SinghEmail author Mukesh?K.?Mahato Babita?Neogi G.?C.?Mondal T.?B.?Singh 《Mine Water and the Environment》2011,30(3):197-207
Ninety nine mine water discharge samples were collected and analyzed for pH, electrical conductivity (EC), major cations,
anions, and trace metals in the Pootkee-Balihari coal mining area of the Jharia coalfield. The mines of the area annually
discharge 34.80 × 106 m3 of mine water and 39,099 t of solute loads. The pH of the analyzed mine waters ranged from 6.97 to 8.62. EC values ranged
from 711 μS cm−1 to 1862 μS cm−1, and reflect variations in lithology, geochemical processes, and hydrological regimes in the mines. The cation and anion
chemistry indicate the general ionic abundance as: Mg2+ > Ca2+ > Na+ > K+ and HCO3
− > SO4
2− > Cl− > NO3
− > F−, respectively. Elevated SO4
2− concentrations in the Gopalichuck, Kendwadih, and Kachhi-Balihari mine waters are attributed to pyrite weathering. The water
quality assessment indicated that TDS, hardness, Mg2+, and SO4
2− are the major parameters of concern in the study area. Except for Fe, all of the measured metals in the mine water were well
within the levels recommended for drinking water. With only a few exceptions, the mine water is of good to permissible quality
and suitable for irrigation. 相似文献
45.
Jayaprakash Behera Swapnita Patra Shaikh Nazrul Satendra Kumar Sharma Deepak Kumar Mahendra Kumar Verma Anil Kumar Katare Sarat K. Swain 《应用聚合物科学杂志》2024,141(16):e55246
Herein, nano boron nitride (BN) laminated poly(ethyl methacrylate) (PEMA)/poly(vinyl alcohol) (PVA) nanocomposite films are fabricated by using a simple in situ polymerization technique with incorporation of silver nanoparticles (Ag NPs). Structural investigations of PEMA/PVA/Ag@BN nanocomposite thin films are carried out by Fourier-transform infrared spectroscopy, dynamic light scattering, X-ray diffraction analysis, 1H nuclear magnetic resonance, 13C nuclear magnetic resonance, and mass spectrometry. The change in morphology of PEMA/PVA matrix due to the reinforcement of BN platelets are identified by electron microscopic studies. The unique tortuous paths are achieved by the dispersion of BN platelets by which gas penetration is restricted with enhancing the barrier properties of the material by 6.5 folds at 5 wt% BN content as compared with neat PEMA/PVA. Acid and alkali resistant along with biodegradability behavior of as-synthesized nanocomposites are studied. From limiting oxygen index (LOI) results, it is found that the prepared materials are fire retardant in nature owing to effective reinforcement of BN layers. Antibacterial activities of PEMA/PVA/Ag@BN nanocomposite are studied by Xanthomonas citri or axonopodis pv. Citri, Escherichia coli, and Xanthomonas oryzae pv. Oryzae because of Ag NPs reinforcement. The substantial improvements in gas barrier, fire retardant, and antibacterial properties enable the materials for packaging application. 相似文献
46.
D. Behera N. C. Mishra K. Patnaik 《Journal of Superconductivity and Novel Magnetism》1997,10(1):27-32
A series of samples of YBa2Cu3-xAgxO7-y with 0≤x≤0.12 composition was studied to probe into the Ag substitution effect on oxygen stoichiometry, lattice parameters,
and superconducting properties. With the samples prepared at a relatively lower sintering temperature, Ag could be doped in
the grains rather than precipitate at grain boundaries. Thus, unlike in the case of YBCO + Ag composites or in doped systems
annealed at high temperatures where Ag occupies mostly the grain boundary, the present system showed a drastic change inT
c, oxygen stoichiometry, and lattice parameters with Ag concentration, indicating the substitution of Ag at the Cu(l) sites
in the grains. The stable 2-fold oxygen coordination of Ag substituting Cu(l)’s explains the observed variation of oxygen
deficiency with Ag. A crystallochemical analysis has been made to reveal the crucial role of Ag-substitution-induced coordination
incompatibility and charge state instability on carrier concentration andT
c. 相似文献
47.
48.
Bikash Chandra Behera Chetan Sudarsan Ghosh Venkateswara Rao Paruchuri 《Machining Science and Technology》2019,23(3):431-454
The present research work aims to understand the chip formation mechanisms in Inconel 718 machining through metallographic technique. The influence of machining speed on shear band and chip shape have been analyzed. Characterization of the shear band has been conducted by analyzing the shear band thickness, strain, strain rate, stress and micro-hardness. Additionally, chip reduction coefficient parameters and chip segmentation ratio parameters have been analyzed to understand the type of chip formation at various machining speeds. The observations and analysis of the same indicated that the formation of the saw-tooth chip is due to high-strain localization within the chip and crack initiation at the free surface of the chip. Thinner shear bands are observed at higher machining speed (120 m/min), and thicker shear bands are observed at lower machining speed (40 m/min). The magnitude of chip segmentation parameters indicates that crack generation increases with increase in machining speed. 相似文献
49.
Samson Paul Pinto Raghavendra Basavapatna Govindasetty Praveen Karanam Upendra Behera Srinivasan Kasthurirengan 《亚洲传热研究》2019,48(4):1264-1279
A low capacity twin‐bed adsorption refrigeration system has been built with R134a as a refrigerant and activated carbon as the adsorbent. Simple tube‐in‐tube heat exchangers have been fabricated and have been used as the adsorber beds. Activated carbon (granular type) has been filled in the annular space of the inner tube and outer tube. A plate heat exchanger has been used as the condenser and the temperature of cooling water has been maintained between 25°C and 30°C, also the evaporator has been custom designed as per requirements. A mathematical model has also been developed and the results obtained have been found to be comparable. While operating the system in the single‐bed mode a cooling power of 250.4 W has been obtained with a coefficient of performance (COP) of 0.38 with an average evaporator temperature of 18.4°C against a predicted value of 263.7 W with a COP of 0.41. While operating in the twin‐bed mode a cooling power of 281.3 W with a COP of 0.47 with an average evaporator temperature of 17.6°C has been obtained against a predicted value of 294.5 W with a COP of 0.52. 相似文献
50.
G. Behera 《Drying Technology》2019,37(6):707-721
The present study was undertaken to develop a pre-drying process of an accelerated water absorption and partial gelatinization of starch in paddy using pulsed microwave-water applications. The experiments on microwave-assisted water absorption by paddy (var. Sworn Masuri) at five power density levels in the range 0.2–1?kW?kg?1 were conducted in a semi-pilot-scale microwave dryer. The paddy was exposed to pre-calculated intermittent water spray and pulsed microwaves up to 100?min. The water absorption kinetics were modeled using modified Azuara’s equation of mass transfer and the process was compared with traditional hot water soaking of the paddy at 60?°C for 3.33?h. The moisture content gained by paddy during microwave-assisted water absorption was faster (30% in 1.67?h) compared to hot water soaking (30% in 3.33?h). The consumption of water, specific energy, and water absorption time during microwave processing were reduced by 70%, 39.51%, and 50%, respectively. The method of slopes was used to estimate moisture diffusivity during microwave-assisted water absorption by paddy. X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) of treated paddy were done to understand the changes in the crystallinity and the microstructure of starch molecules. The microwave-assisted water absorption process was found to accelerate the moisture gain with the effect of partial gelatinization of starch in the paddy. Further, the experiment can be continued in the same microwave dryer to fully gelatinize the paddy at 30% moisture content and dry the gelatinized paddy. 相似文献