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Yadav D.,Keshav Mahavidyalaya | Singh S.R.,P.A. College | Kumari R.,P.A. College
OPSEARCH | Year: 2013

In this paper, an inventory model is developed to deal the impreciseness present in market demand. It is assumed that the received items are not of perfect quality and after screening; imperfect items are withdrawn from inventory and sold at discounted price. However, in practice, errors occur in screening test. So, the screening process fails to be perfect. Due to acquaintance with handling methodology and system, holding cost and ordering cost are gradually decreases from one shipment to another. So, learning effect is incorporated on holding cost, ordering cost and number of defective items present in each lot. This type of situation arises in many industries especially for that industry where productivity is influenced by human labour needed for final assembly such as: cars, ships, machines, aircrafts, electronics, and stabilizer. Due to impreciseness in market demand, profit expression is fuzzy in nature. To fuzzify the profit expression, Extension Principle is used and for defuzzification centroid method is applied. Mathematically, it is shown that profit expression is concave in nature. Finally, the feasibility of proposed model and the effect of learning on optimal solution are shown through numerical example. © 2013 Operational Research Society of India.

Mahajan S.,CMET - Photonics And Advanced Materials Laboratory | Mahajan S.,Solid State Group | Haridas D.,Keshav Mahavidyalaya | Thakur O.P.,Solid State Group | Prakash C.,Extramural Research and Intellectual Property Rights ERandIPR
Materials Letters | Year: 2013

In present work, we have studied dilatometric thermal expansion, densification and grain growth behavior of lead free ferroelectric [BaZr xTi1-xO3 (x=0.05)] ceramic which was prepared by conventional solid state reaction method. Dilatometric thermal expansion measurements were performed from room temperature to 1400 °C in order to determine shrinkage and reaction kinematics of the BZT ceramics. About 10% shrinkage was observed in a temperature range of 1050-1400 °C and in isothermal shrinkage plot; different slopes were observed, indicating different shrinkage mechanisms involved. © 2012 Elsevier B.V.

Mahajan S.,MET Tech | Mahajan S.,University of Delhi | Haridas D.,Keshav Mahavidyalaya | Sreenivas K.,University of Delhi | And 2 more authors.
Materials Letters | Year: 2013

Recently, lead-free piezoelectric ceramics have widely attracted interest among the research community, as they are considered to be potential substitutes for lead-based ceramics which causes environmental pollution due to the presence of hazardous lead oxide in them. In the present study we have synthesized La doped Ba1-x/2Lax/3(ZryTi 1-y)O3 (x=0-0.06 in steps of 0.02; y=0, 0.05) ceramics by the conventional solid-state reaction method. Results reveal that electric field induced strain increases from ∼0.08% to ∼0.18% (at 40 kV/cm applied field) for x=0.02 and y=0.05 of lanthanum and zirconium substitution respectively compared to undoped BaTiO3. It was also observed that, sample with 2 mol% lanthanum could sustain higher electric field upto 120 kV/cm during strain measurement (without electrical breakdown) and results showed highest strain value of ∼0.3% in this system. © 2013 Elsevier B.V.

Mahajan S.,MET Tech | Mahajan S.,University of Delhi | Haridas D.,Keshav Mahavidyalaya | Ali S.T.,MET Tech | And 4 more authors.
Physica B: Condensed Matter | Year: 2014

In present study we have prepared ferroelectric BaZrxTi 1-xO3 (x=0.05) ceramic by conventional solid state reaction route and studied its electrical properties as a function of temperature and frequency. X-ray diffraction (XRD) analysis shows single-phase formation of the compound with orthorhombic crystal structure at room temperature. Impedance and electric modulus spectroscopy analysis in the frequency range of 40 Hz-1 MHz at high temperature (200-600 °C) suggests two relaxation processes with different time constant are involved which are attributed to bulk and grain boundary effects. Frequency dependent dielectric plot at different temperature shows normal variation with frequency while dielectric loss (tanδ) peak was found to obey an Arrhenius law with activation energy of 1.02 eV. The frequency-dependent AC conductivity data were also analyzed in a wide temperature range. © 2014 Elsevier B.V.

Yadav D.,Keshav Mahavidyalaya | Singh S.R.,P.A. College | Kumari R.,Meerut College
International Journal of Systems Science | Year: 2015

Trade credit plays an important role in financing many industries. In the classical inventory model it is assumed that the buyer must pay for the items as soon as the items are received. In this problem, it is considered that the retailer can pay the supplier either at the end of the credit period or later pay interest on the unpaid amount for the overdue period. Here, the retailer's inventory model for the optimal cycle time and payment time for a retailer is developed. The effects of the inflation rate, deterioration rate and delay in payment have been discussed. The whole study is performed in a fuzzy environment by taking the opportunity cost, interest earned and interest paid rate as a triangular fuzzy number. Fuzzy profit functions, which involve fuzzy arithmetic operation, are defined using the function principle. We use the signed distance method to defuzzify the fuzzy profit function. Moreover, numerical and sensitivity analysis is performed to validate the proposed model. © 2013 Taylor and Francis.

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