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Yadava, P.S.,A. Sarjubala Devi 한국생태학회 2004 Journal of Ecology and Environment Vol.27 No.4
The impact of slash and burning on microbial biomass C, N and P in soils of semi-evergreen tropical deciduous forest were studied from February 1999 to January 2000. The experimental sites were located near Moreh town in the Chandel district of Manipur state (India) along the Indo-Myanmar border between 23°49′ N ~ 24°28′N latitude and 93°45′E ~ 94°16′E longitude. Microbial biomass C ranged from 319.50 μg g-1 to 905.50 μg g-1 in the slash and burnt site and from 209.50 μg g-1 to 708.80 μg g-1 soil in the forest site. Microbial N ranged from 19.30 μg g-1 to 99.45 μg g-1 in the slash and burnt site and from 16.08 μg g-1 to 88.90 μg g-1 in the forest site. Microbial P varied from 10.90 μg g-1 to 32.21 μg g-1 in the slash and burnt site and from 2.50 μg g-1 to 17.60 μg g-1 in the forest site in different months throughout the year. Microbial biomass C, N and P were recorded to be higher in the slash and burnt site compared to the forest site .The conversion of forest into slash and burnt site for agriculture - the traditional shifting cultivation practiced by tribal people in the north- eastern India leads to addition of large amount of organic matter in the soil thereby exhibiting higher values of microbial biomass C, N and P in the recent slash and burnt site than that of the forest site. Relationship between the soil moisture, soil organic C and microbial biomass C, N and P were found to be correlated significantly in both the sites.
Viscosities of binary mixtures of ethanenitrile with benzene and several substituted benzenes
Sarvanand Singh Yadava,Shrinath Singh,Rati Bhan,Neetu Yadav 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.1
Viscosities (η) and densities (ρ) of five binary mixtures of ethanenitrile with benzene and several substituted benzenes viz methylbenzene, 1,4-dimethylbenzene, chlorobenzene and 1,2-dichlorobenzene have been experimentally determined at 308.15 K. Viscosity deviations (Δη) from the linear blending rule have been evaluated for all the mixtures studied. These are small with a maximum negative deviation of about 6% for binary mixture with benzene and maximum positive deviation of about 3% for mixture with 1,4-dimethylbenzene. Δη Values are fitted into Redlich -Kister equation and standard deviations in Δη values, σ (Δη) have been evaluated. The correlating performance of several viscosity models such as Grunberg - Nissan, Katti and Chaudhari, Hind-McLaughlin - Ubbelohde and Sedgwick has been evaluated. Grunberg-Nissan viscosity model is suitable for viscosities of several binary systems studied. The results are discussed in terms of molecular interactions between the components of binary mixtures.
Singh, L.,Yadava, S. S.,Sin, B. C.,Rai, U. S.,Mandal, K. D.,Lee, Y. Springer Science + Business Media 2016 Journal of electronic materials Vol.45 No.6
<P>The dielectric and ferroelectric characteristics of Bi0.5Na0.5TiO3 (BNT), CaCu3Ti4O12 (CCTO), and 0.5Bi(0.5)Na(0.5)TiO(3)-0.5CaCu(3)Ti(4)O(12) (BNT/CCTO) ceramics are compared. X-ray diffraction patterns confirmed the formation of single phase of all the ceramics after sintering at 950A degrees C for 15 h. Scanning electron microscopy images of the sintered ceramics reveal average grain sizes in the range from 200 nm to 2.5 mu m. Energy-dispersive x-ray mapping and x-ray photoelectron spectroscopy show the presence of the elements Bi, Na, Ca, Cu, Ti, and O with uniform distribution in the ceramics. BNT/CCTO exhibits high dielectric constant (epsilon (r) similar to 6.9 x 10(4)) compared with BNT (epsilon (r) similar to 0.13 x 10(4)) and CCTO (epsilon (r) similar to 1.68 x 10(4)) ceramics at 1 kHz and 503 K. The high dielectric constant of BNT/CCTO compared with BNT and CCTO is associated with a major contribution from grain boundaries, as confirmed by impedance and modulus analyses. The P-E hysteresis loop of all the ceramics measured at room temperature and 50A degrees C exhibited typical ferroelectric nature. The remanent polarization (P (r)) of BNT (1.58 mu C/cm(2)) and CCTO (0.654 mu C/cm(2)) ceramics are higher than that of BNT/CCTO (0.267 mu C/cm(2)) ceramic.</P>
Slotted-electrical discharge diamond cut-off grinding of Al/SiC/B4C hybrid metal matrix composite
Ravindra Nath Yadav,Vinod Yadava 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.1
Advanced manufacturing industries need materials with high strength and low weight in the fields of advanced engineering, such asautomobiles and aeronautics. Metal matrix composites (MMCs) are one of the advanced engineering materials that meet the above requirements. To enhance the properties of MMCs, researchers added an additional phase of reinforcements into single reinforced MMCs,such developed MMCs are known as hybrid MMCs. The additional phase of reinforcements enhances the properties of MMCs, but simultaneouslyleads to rapid tool wear and poor machinability. This study developed an innovative hybrid machining process (HMP)consisting of electrical discharge grinding and diamond grinding in such a way that both the processes occur alternately with equal intervalsdue to the rotation of a slotted abrasive grinding wheel. The performance of the hybrid process was tested on an Al/SiCp/B4Cp workpiecein cut-off grinding mode. The experiments were conducted on an electrical discharge machining machine, which consists of a separateattachment on a vertical column to rotate the wheel. Pulse current, pulse on-time, pulse off-time, wheel RPM, and abrasive grit numberwere taken as input parameters while material removal rate (MRR) and average surface roughness were taken as output parameters. Result were shown that the HMP gives higher MRR with better surface finish as compared to the constituent processes. Pulse currentranging from 3 A to 21 A, pulse on-time ranging from 30 μs to 200 μs, and pulse off-time ranging from 15 μs to 90 μs were also found tobe more suitable for higher MRR, and a wheel RPM at 1300 RPM was more suitable for higher MRR with better surface finish.
Experimental Study of Erosion and Abrasion based Hybrid Machining of Hybrid Metal Matrix Composite
Ravindra Nath Yadav,Vinod Yadava 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
Machining of metal matrix composites (MMCs) are still a challenge for manufacturing industries. Among various machining processes, electrical discharge machining (EDM) and diamond grinding (DG) are more acceptable processes for machining of the MMCs. In this paper, a new compound wheel (CW) is developed in such a way that both processes (EDM and DG) occur in alternate way due to the rotation of wheel. The performance of erosion and abrasion based hybrid machining (EAHM)process has been tested on hybrid aluminium-silicon carbide-graphite (Al/SiC/Gr) composite in terms of material removal rate (MRR) and average surface roughened (Ra). The experiments have been conducted on EDM machine with application of CW for effective spark erosion and abrasive abrasion machining. The effects of pulse current, pulse duration, pulse interval and wheel speed on MRR and Ra has been experimentally investigated and discussed.
Bellampalli Praveen Naik,Yadava Neelam 한국사회복지학회 2022 Asian Social Work and Policy Review Vol.16 No.2
Migration is an essential livelihood strategy in rapidly developing, low-income contexts. However, this article seeks to analyze occupation choices and the struggle for livelihood among laborers. This study carried out both secondary and primary data; the primary survey was conducted in the Udupi district of Karnataka. Detailed information was gathered from both individual and household levels. According to National Sample Survey data, construction offers the main occupation for short duration migrants, absorbing 36.2% of total short duration migration. However, the field survey findings indicated that at the destination, the construction sector migrants are more vulnerable and struggle for their lives and livelihood in the urban labor segments—poverty and rural unemployment a significant reasons to push the laborers into the construction segment.
Electrochemical Magnetic Abrasive Machining of AISI304 Stainless Steel Tubes
Kesarbhai Bhikhabhai Judal,Vinod Yadava 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.
This work presents the characteristics of advanced abrasion based hybrid machining process consisting of electrochemical dissolution and magnetic abrasive machining process. The cylindrical electrochemical magnetic abrasive machining (C-EMAM) setup was developed and mounted as an attachment on lathe for high efficiency machining of cylindrical jobs. Experiments were conducted to explore the performance of the process on AISI-304 stainless steel tubes using unbonded magnetic abrasives. The effect of various process parameters viz. rotational speed of the workpiece, current to the electromagnet, electrolytic current and frequency of vibration on material removal and surface roughness were investigated. The electrochemical process has major contribution in material removal, whereas magnetic abrasive machining helps in reduction in surface roughness. This process has higher machining efficiency particularly at high value of electrolytic current and high rotational speed.