Modeling Nearly Spherical Pure-bulge Galaxies with a Stellar Mass-to-light Ratio Gradient under the ΛCDM and MOND Paradigms. I. Methodology, Dynamical Stellar Mass, and Fundamental Mass Plane

Chae, Kyu-Hyun,Bernardi, Mariangela,Sheth, Ravi K. American Astronomical Society 2018 The Astrophysical journal Vol.860 No.1

<P>We carry out spherical Jeans modeling of nearly round pure-bulge galaxies selected from the ATLAS(3D) sample. Our modeling allows for gradients in the stellar mass-to-light ratio (M-star /L) through analytic prescriptions parameterized with a 'gradient strength' K introduced to accommodate any viable gradient. We use a generalized Osipkov-Merritt model for the velocity dispersion (VD) anisotropy. We produce Monte Carlo sets of models based on the stellar VD profiles under both the Lambda CDM and MOND paradigms. Here, we describe the galaxy data, the empirical inputs, and the modeling procedures of obtaining the Monte Carlo sets. We then present the projected dynamical stellar mass, M-star e, within the effective radius R-e, and the fundamental mass plane (FMP) as a function of K. We find the scaling of the K-dependent mass with respect to the ATLAS3D reported mass as: log(10)[M-star e(K)/M-star e(A3D)] = a' + b'K with a' = -0.019 +/- 0.012 and b' = -0.18 +/- 0.02 (Lambda CDM), or a' = -0.023 +/- 0.014 and b' = -0.23 +/- 0.03 (MOND), for 0 <= K < 1.5. The FMP has coefficients consistent with the virial expectation and only the zero-point scales with K. The median value of K for the ATLAS(3D) galaxies is K = 0.53(-0.04)(+0.05). We perform a similar analysis of the much larger SDSS DR7 spectroscopic sample. In this case, only the VD within a single aperture is available, so we impose the additional requirement that the VD slope be similar to that in the ATLAS(3D) galaxies. Our analysis of the SDSS galaxies suggests a positive correlation of K with stellar mass.</P>

X-ray Absorption and Emission Spectroscopic Studies of BiMn2-xTixO5 (0 ≤ x ≤ 0:5)

K. H. Chae,P. Thakur,황정남,G. S. Chang,D. K. Shukla,S. Mollah,Ravi Kumar 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.3

The electronic structure of the multiferroic BiMn2-xTixO5(0 ≤ x ≤ 0:5) system was studied by using X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES). The polycrystalline bulk BiMn2-xTixO5 samples were synthesized using a conventional solid-state reaction technique. XAS and XES spectroscopic studies on the O K-, Mn K-, L3;2- and Ti L3;2-edges of the BiMn2-xTixO5 samples and of the reference compounds were performed and the results were compared in order to determine the exact chemical states of functioning ions. The O K-edge XAS and XES results demonstrate a competition between the Mn 3d and the Ti 3d orbitals on hybridizations with the O 2p orbital. The Mn K- and Mn L3;2-edge XAS spectra suggest that the Mn3+ /Mn4+ ratio increases with increasing Ti doping and drives the system towards octahedral symmetry. On the other hand, Ti ions remain at 4+ states for all compositions, as shown by the Ti L-edge XAS. Here, we present and discuss the detailed electronic structures of the BiMn2-xTixO5 samples.

X-ray Absorption Spectroscopic Studies of Pulsed-Laser-Deposited Thin Films of Fe3O4 on Si(111) Substrate

P. Thakur,W. K. Choi,K. H. Chae,J.-Y. Kim,R. J. Choudhary,Shailja Tiwari,Ram Prakash,D. M. Phase,Ravi Kumar 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.6

We report on the growth and the characterization of magnetite thin films grown on Si(111) substrates by using pulsed laser deposition at different substrate temperatures (TS = 350, 450 and 550 ℃) by performing X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) experiments. The O K− and Fe L3,2−edge XAS spectra reveal that the couplings of the O 2p with Fe 3d orbitals highly rely on the growth processes. The XMCD data of well-characterized thin films exhibit characteristic contributions from Fe3+ A ions in tetrahedral sites and Fe2+ B and Fe3+ B ions in octahedral sites and have spectral features similar to those of the Fe3O4 single crystal. The temperature dependence of the XMCD line shape features remain unchanged below and above the Verwey transition. These investigations demonstrate the experimental conditions for controlled growth of Fe3O4 thin films on Si(111) substrates and suggest that the Fe3O4/Si(111) might a promising spintronic materials for future technology.

Intrinsic Channel Mobility of Amorphous, In–Ga–Zn–O Thin-Film Transistors by a Gated Four-Probe Method

Mativenga, Mallory,Sungjin An,Suhui Lee,Jaegwang Um,Di Geng,Mruthyunjaya, Ravi K.,Heiler, Gregory N.,Tredwell, Timothy J.,Jin Jang IEEE 2014 IEEE transactions on electron devices Vol.61 No.6

<P>Intrinsic mobility and intrinsic channel resistance (R<SUB>CH</SUB>) of amorphous, In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) with varying channel length (L) are investigated using a gated four-probe back-channel-etched TFT design. The intrinsic R<SUB>CH</SUB> is found to decrease from ~500 to ~250 kΩ per unit area by increasing V<SUB>GS</SUB> from 10 to 20 V. The intrinsic mobility is ~17 cm<SUP>2</SUP>/V·s, which is about 20% higher than that derived from the normal two-point probe measurements. Source and drain parasitic resistance (R<SUB>PAR</SUB>) of the a-IGZO TFTs is found to be of the same order of magnitude as the R<SUB>CH</SUB>-which is different from hydrogenated amorphous-silicon (a-Si:H) TFTs, where TFT operation is dominated by R<SUB>PAR</SUB>.</P>

INTERVAL-VALUED FUZZY REGULAR LANGUAGE

Ravi, K.M.,Alka, Choubey The Korean Society for Computational and Applied M 2010 Journal of applied mathematics & informatics Vol.28 No.3

In this paper, a definition of interval-valued fuzzy regular language (IVFRL) is proposed and their related properties studied. A model of finite automaton (DFA and NDFA) with interval-valued fuzzy transitions is proposed. Acceptance of interval-valued fuzzy regular language by the finite automaton (DFA and NDFA) with interval-valued fuzzy transitions are examined. Moreover, a definition of finite automaton (DFA and NDFA) with interval-valued fuzzy (final) states is proposed. Acceptance of interval-valued fuzzy regular language by the finite automaton (DFA and NDFA) with interval-valued fuzzy (final) states are also discussed. It is observed that, the model finite automaton (DFA and NDFA) with interval-valued fuzzy (final) states is more suitable than the model finite automaton (DFA and NDFA) with interval-valued fuzzy transitions for recognizing the interval-valued fuzzy regular language. In the end, interval-valued fuzzy regular expressions are defined. We can use the proposed interval-valued fuzzy regular expressions in lexical analysis.

Impact of Marketing Losses on Efficiency in Transacting Banana in Scarce Rainfall Zone of Andhra Pradesh, India

K. Nirmal Ravi Kumar 한국농식품정보과학회 2017 Agribusiness and Information Management Vol.9 No.2

Introduction: To analyze the impact of marketing losses on efficiency in transacting banana in Kurnool district of SRZ in Andhra Pradesh and to assess the opinions of the farmers on the constraints in transacting banana. Research back ground, Materials and Methods: The study relies exclusively on primary information obtained from the banana farmers of Kurnool District. Purposive sampling procedure was followed for the selection of the study area. Top two mandals in the district and top two villages in each mandal are selected in accordance with the area under cultivation of banana. Probability proportion to size was followed regarding the selection of sample farmers and accordingly 60 marginal, 37 small and 23 other farmers were selected and thereby, the total sample size was 120. Result and Discussion: Three marketing channels were identified in the marketing of banana in Kurnool district viz., Producer → Local-exporter → Wholesaler → Retailer → Consumer (Channel-I), Producer → Wholesaler → Cart-vendor → Consumer (Channel-II) and Producer → Juice-holder → Consumer (Channel-III). With the inclusion of marketing losses in the price spread analysis of banana in all the three channels, the marketing costs of all the intermediaries were increased and thereby, the farmer’s share in consumer’s rupee and Net Marketing Margins of the agencies are on the decline. So, without inclusion of marketing losses, the farmer’s share in consumer’s rupee and Net Marketing Margins of all the agencies are overvalued. The higher the marketing losses, the more is the negative impact on farmer’s net selling price, net marketing margins of the intermediaries and marketing efficiency. The sample farmers are facing major problems in marketing of banana like frequent price fluctuations, unorganized marketing and lack of transportation facilities on priority basis. Suggestions: It is suggested to educate the farmers regarding the optimum maturity index for harvest, use of mechanical harvesters, proper placement of fruits during storage and ripening, better packaging and cushioning technologies to absorb shocks during transportation, strengthening of storage facilities and transport facilities, encourage co-operative marketing etc., to promote marketing efficiency of banana in the study area.

Performance of Drip Irrigation System in Banana Cultuivation – Data Envelopment Analysis Approach

K Nirmal Ravi Kumar,M Suresh Kumar 한국농식품정보과학회 2016 Agribusiness and Information Management Vol.8 No.1

India is largest producer of banana in the world producing 29.72 million tonnes from an area of 0.803 million ha with a productivity of 35.7 MT ha-1 and accounted for 15.48 and 27.01 per cent of the world’s area and production respectively (www.nhb.gov.in). In India, Tamil Nadu leads other states both in terms of area and production followed by Maharashtra, Gujarat and Andhra Pradesh. In Rayalaseema region of Andhra Pradesh, Kurnool district had special reputation in the cultivation of banana in an area of 5765 hectares with an annual production of 2.01 lakh tonnes in the year 2012-13 and hence, it was purposively chosen for the study. On 23rd November 2003, the Government of Andhra Pradesh has commenced a comprehensive project called ‘Andhra Pradesh Micro Irrigation Project (APMIP)’, first of its kind in the world so as to promote water use efficiency. APMIP is offering 100 per cent of subsidy in case of SC, ST and 90 per cent in case of other categories of farmers up to 5.0 acres of land. In case of acreage between 5-10 acres, 70 per cent subsidy and acreage above 10, 50 per cent of subsidy is given to the farmer beneficiaries. The sampling frame consists of Kurnool district, two mandals, four villages and 180 sample farmers comprising of 60 farmers each from Marginal (<1ha), Small (1-2ha) and Other (>2ha) categories. A well structured pre-tested schedule was employed to collect the requisite information pertaining to the performance of drip irrigation among the sample farmers and Data Envelopment Analysis (DEA) model was employed to analyze the performance of drip irrigation in banana farms. The performance of drip irrigation was assessed based on the parameters like: Land Development Works (LDW), Fertigation costs (FC), Volume of water supplied (VWS), Annual maintenance costs of drip irrigation (AMC), Economic Status of the farmer (ES), Crop Productivity (CP) etc. The first four parameters are considered as inputs and last two as outputs for DEA modelling purposes. The findings revealed that, the number of farms operating at CRS are more in number in other farms (46.66%) followed by marginal (45%) and small farms (28.33%). Similarly, regarding the number of farmers operating at VRS, the other farms are again more in number with 61.66 per cent followed by marginal (53.33%) and small farms (35%). With reference to scale efficiency, marginal farms dominate the scenario with 57 per cent followed by others (55%) and small farms (50%). At pooled level, 26.11 per cent of the farms are being operated at CRS with an average technical efficiency score of 0.6138 i.e., 47 out of 180 farms. Nearly 40 per cent of the farmers at pooled level are being operated at VRS with an average technical efficiency score of 0.7241. As regards to scale efficiency, nearly 52 per cent of the farmers (94 out of 180 farmers) at pooled level, either performed at the optimum scale or were close to the optimum scale (farms having scale efficiency values equal to or more than 0.90). Majority of the farms (39.44%) are operating at IRS and only 29 per cent of the farmers are operating at DRS. This signifies that, more resources should be provided to these farms operating at IRS and the same should be decreased towards the farms operating at DRS. Nearly 32 per cent of the farms are operating at CRS indicating efficient utilization of resources. Log linear regression model was used to analyze the major determinants of input use efficiency in banana farms. The input variables considered under DEA model were again considered as influential factors for the CRS obtained for the three categories of farmers. Volume of water supplied (X1) and fertigation cost (X2) are the major determinants of banana farms across all the farmer categories and even at pooled level. In view of their positive influence on the CRS, it is essential to strengthen modern irrigation infrastructure like drip irrigation and offer more fertilizer subsidies to the farmer to enhance the crop production on cost-effective basis in Kurnool district of Andhra Pradesh, India. This study further suggests that, the present era of Information Technology will help the irrigation management in the context of generating new techniques, extension, adoption and information. It will also guide the farmers in irrigation scheduling and quantifying the irrigation water requirements in accordance with the water availability in a particular season. So, it is high time for the Government of India to pay adequate attention towards the applications of ‘Information and Communication Technology (ICT) and its applications in irrigation water management’ for facilitating the deployment of Decision Supports Systems (DSSs) at various levels of planning and management of water resources in the country.

Bridging Research and Extension Gaps of Paddy Yield in Andhra Pradesh, India

K. Nirmal Ravi Kumar 한국농식품정보과학회 2018 Agribusiness and Information Management Vol.10 No.1

Many paddy cultivating farmers in the country are forced to use their limited resources to produce adequate food for their family, leading to the degradation and reduction in potential of these resources. The yield levels of paddy at the farmers’ level and in the Front Line Demonstrations (FLDs) conducted in the farmers’ fields is not at par with potential yield of the paddy variety. The gap between potential yield of crop variety and yield realized in FLDs refers to Research gap and the yield gap between FLDs and due to farmers’ practice refers to Extension gap. The earlier studies conducted in India in general and in Andhra Pradesh in particular highlighted the existence of both research and extension gaps with reference to paddy. It is essential that, the narrowing of both research and extension gaps is not static, but dynamic considering the influence of technological interventions in boosting paddy yields at FLDs level and at farmers’ level and also with the improvement of the yield potential of paddy varieties. This calls for integrated and holistic approaches to address these two gaps and with this background, the researcher aimed at this in depth study. The findings revealed that, research gaps are high with reference to weed management and pest management and extension gaps are high with reference to farm mechanization followed by fertilizer management. Reliable source of seed, capital use and frequency of meetings with Scientists or Agricultural Officers significantly influence the extension gaps in paddy. Farmers also prioritized socio-economic and technical constraints and the analysis infers that, it is high time now for the farmers to adopt the planned technological interventions on scientific scale to minimize the extension gaps to the extent possible. As the enabling environment in the State of Andhra Pradesh is highly encouraging for the farmers with relevant policy instruments in the form of subsidized inputs, free power, credit at concessional rates of interest, constructing irrigation projects etc., the adoption of the proposed technological interventions significantly contribute to minimizing both research and extension gaps in paddy cultivation in Kurnool district of Andhra Pradesh.

Efficient Utilisation of Credit by the Farmer - Borrowers in Chittoor District of Andhra Pradesh, India - Data Envelopment Analysis Approach

K. Nirmal Ravi Kumar 한국농식품정보과학회 2016 Agribusiness and Information Management Vol.8 No.2

The present study has aimed at analyzing the technical and scale efficiencies of credit utilization by the farmer-borrowers in Chittoor district of Andhra Pradesh, India. DEA approach was followed to analyze the credit utilization efficiency and to analyze the factors influencing the credit utilization efficiency, log-linear regression analysis was attempted. DEA analysis revealed that, the number of farmers operating at CRS are more in number in marginal farms (40%) followed by other (35%) and small (17.5%) farms. Regarding the number of farmers operating at VRS, small farmers dominate the scenario with 72.5 per cent followed by other (67.5%) and marginal (42.5%) farmers. With reference to scale efficiency, marginal farmers are in majority (52.5%) followed by other (47.5%) and small (25%) farmers. At the pooled level, 26.7 per cent of the farmers are being operated at CRS, 63 per cent at VRS and 32.5 per cent of the farmers are either performed at the optimum scale or were close to the optimum scale (farms having scale efficiency values equal to or more than 0.90). Nearly 58, 15 and 28 percents of the farmers in the marginal farms category were found operating in the region of increasing, decreasing and constant returns respectively. Compared to marginal farmers category, there are less number of farmers operating at CRS both in small farmers category (15%) and other farmers category (22.5%). At the pooled level, only 5 per cent of the farmers are operating at DRS, majority of the farmers (73%) are operating at IRS and only 22 per cent of the farmers are operating at CRS indicating efficient utilization of credit. The log-linear regression model fitted to analyze the major determinants of credit utilization (technical) efficiency of farmer- borrowers revealed that, the three variables viz., cost of cultivation and family expenditure (both negatively influencing at 1% significant level) and family income (positively influencing at 1% significant level) are the major determinants of credit utilization efficiency across all the selected farmers categories and at pooled level. The analysis further indicate that, escalation in the cost of cultivation of crop enterprises in the region, rise in family expenditure and prior indebtedness of the farmers are showing adverse influence on the credit utilization efficiency of the farmer-borrowers.

Opportunities for Agricultural Water Management Interventions in the Krishna Western Delta - A case from Andhra Pradesh, India

K. Nirmal Ravi Kumar 한국농식품정보과학회 2017 Agribusiness and Information Management Vol.9 No.1

Abstract2)Agricultural water management has gained enormous attention in the developing world to alleviate poverty, reduce hunger and conserve ecosystems in small-scale production systems of resource-poor farmers. The story of food security in the 21stcentury in India is likely t o be closely linked to the story of water security. Today, the water resource is under severe threat. The past experiences in India in general and in Andhra Pradesh in particular, indicated inappropriate management of irrigation has led to severe problems like excessive water depletion, reduction in water quality, water logging, salinization, marked reduction in the annual discharge of some of the rivers, lowering of ground water tables due to pumping at unsustainable rates, intrusion of salt water in some coastal areas etc. Considering the importance of irrigation water resource efficiency, Krishna Western Delta (KWD) of Andhra Pradesh was purposively selected for this in depth study, as the farming community in this area are severely affected due to severe soil salinity and water logging problems and hence, adoption of different water saving crop production technologies deserve special mention. It is quite disappointing that, canals, tube wells and filter points and other wells could not contribute much to the irrigated area in KWD. Due to less contribution from these sources, the net area irrigated also showed declining growth at a rate of –6.15 per cent. Regarding paddy production, both SRI and semi-dry cultivation technologies involves less irrigation cost (Rs. 2475.21/ha and Rs. 3248.15/ha respectively) when compared to transplanted technology (Rs. 4321.58/ha). The share of irrigation cost in Total Operational Cost (TOC) was highest for transplanted technology of paddy (11.06%) followed by semi-dry technology (10.85%) and SRI technology (6.21%). The increased yield and declined cost of cultivation of paddy in SRI and semi-dry production technologies respectively were mainly responsible for the low cost of production of paddy in SRI (Rs. 495.22/qtl) and semi-dry (Rs. 532.81/qtl) technologies over transplanted technology (Rs. 574.93/qtl). This clearly indicates that, by less water usage, paddy returns can be boosted by adopting SRI and semi-dry production technologies. Both the system-level and field-level interventions should be addressed to solve the issues/problems of water management. The enabling environment, institutional roles and functions and management instruments are posing favourable picture for executing the water management interventions in the State of Andhra Pradesh in general and in KWD in particular. This facilitates the farming community to harvest good crop per unit of water resource used in the production programme. To achieve better results, the Farmers’ Organizations, Water Users Associations, Department of Irrigation etc., will have to aim at improving productivity per unit of water drop used and this must be supported through system-wide enhancement of water delivery systems and decision support tools to assist farmers in optimizing the allocation of limited water among crops, selection of crops based on farming situations, and adoption of appropriate alternative crops in drought years.