Chaman Singh

Supply chain model with stochastic lead time under imprecise partially backlogging and fuzzy ramp-type demand for expiring items

The objective of this research is to develop a multi-echelon supply chain model with fuzzy ramp-type demand rate and imprecise partial backlogging rate of unsatisfied demand, considering the effect of inflation and time value of money. Suppliers lead time is a stochastic function of his managing cost. The extra costs incurred on retailer, due to the uncertain lead time in terms of shortages costs or lost sales costs are owed by the supplier. The items have a certain expiration date, due to the fact there is decline in the demand rate with time, but after a period of time it becomes steady. A numerical example is cited to illustrate the results and its significant features. Finally, to study the effect of changes of demand parameters, deterioration, inflation and partially backlogging rate on suppliers and the retailers profit, a sensitivity analysis is presented numerically.

Imperfect production process with exponential demand rate, Weibull deterioration under inflation

In this research, an integrated production inventory model is developed from the perspective of both the manufacturer and the retailer. The model assumes exponential demand rate, production rate is demand dependent under the inflation, imperfect production process and multiple deliveries. We have assumed that the produced items deteriorates at a constant rate at the producer’s end due to the proper storages conditions, and as the items reaches the retailer’s end follows the Weibull deterioration. Shortages are allowed at the retailer’s part only and the unfulfilled demand is partially backlogged. A numerical example along with sensitivity analysis is given to illustrate the model. Integrated cost policy is compared with the independent decisions made by the manufacturer and the retailer’s and the necessary conclusions are made. Mathematica5.2 is being used to reach the optimal policies.

Integrated Supply Chain Model for Perishable Items with Trade Credit Policy under Imprecise Environment

the purpose of this paper to investigate the integrated cost minimizing strategy with suppliers trade credits offer under fuzzy environment. Supplier permits the retailer a certain fixed period to settle the amount owed to him for the items supplied. Expressions for average integrated inventory cost in fuzzy sense are derived Signed Distance Method is used to defuzzified total fuzzy cost and its optimization with respect to the decision variable is carried out. A numerical example is cited to illustrate the model. A comparison is made between integrated cost policy and the individual cost polices. It is shown that integrated cost policy results in impressive cost reduction. Computer software Mathematics 7.0 is used to derive the optimal policies.

A spectroscopic ellispometric study of the tunability of the optical constants and thickness of GeOx films with swift heavy ions

Sub-stoichiometric GeOx films were fabricated by electron-beam evaporation method. The films were irradiated with 100 MeV Ag7+ ions at fluences between 1 × 1012 and 1 × 1014 ions-cm−2. Spectroscopic ellipsometric measurements were performed in air at room temperature. The values of the layer thickness and refractive index were extracted from ellipsometry using a multilayer analysis and the Tauc Lorentz model. The refractive index (at 633 nm) of the as-deposited GeOx film was estimated to be 1.860 and decreased to 1.823 for films irradiated at an ion fluence of 1 × 1014 ions-cm−2. The thickness of the films also decreased after irradiation and is due to a sputtering induced by the ion beam. The change in the refractive index with ion fluence is attributed to a stoichiometric change and structural transformation represented by GeOx→ Ge + GeOy (y > x) occurring due to a thermal spike induced by ion irradiation. Swift heavy ions thus provide a scope for modulating the refractive index of GeOx films. The thick...

An EPQ Model with Power-form Stock Dependent Demand under Inflationary Environment using Genetic Algorithm

In this paper a production inventory model for the newly launched product is developed incorporating the effect of inflation and time value of money. The objective of this study is to find the economic production quantities. It is assumed that demand of the items is displayed stock dependent. Production is stopped when the stock-level reached to level Q and Q0 is the fixed stock-level. In this paper we discussed the following two situations (I) Q  Q0 and (II) Q > Q0. Model is formulated to maximize the total profit. A genetic algorithm with varying population size is used to solve the model. In this GA a subset of better children is included with the parent population for next generation and size of this subset is a percentage of the size of its parent set. Numerical example is given to illustrate the model. Sensitivity analysis with respect to various parameters is also presented.

Spectroscopic ellipsometry study of the free-carrier and band-edge absorption in ZnO thin films: Effect of non-stoichiometry

The effect of stoichiometry on the complex dielectric function (e(E) = e1(E) + ie2(E)), and thereby on the optical and electrical properties, of rf-sputtered polycrystalline ZnO films was investigated using spectroscopic ellipsometry in the UV-VIS-NIR range. The stoichiometry and the density of the films were quantified by Rutherford backscattering spectroscopy. The lineshape of the dielectric function was fitted using the Tauc-Lorentz multi-oscillator and Drude models. The stoichiometric as well as the sub-stoichiometric films showed a high optical transparency in the visible and a bandgap absorption in the UV region. In the NIR region, however, the sub-stoichiometric films showed a significant increase in absorption with decreasing energy while the absorption was negligible for the stoichiometric films. This difference in behavior is attributed to the presence of free-carriers in the sub-stoichiometric films, whose concentration was determined to be around 4 × 1020 cm−3 from spectroscopic ellipsometry. ...

Progressive trade credit policy in a supply chain with and without stock-out for supplier's lead time under inflationary and fuzzy environment

In this paper, we have developed a progressive trade credit model with and without stock-out for retailer under suppliers promised lead time incorporating the effect of inflation and time value of money. Supplier is not always in a position to fulfil retailers request at any time, and thus forced to adopt new policies to deal with the situation. To deal with the situation, the supplier does not hold the inventory indeed, but produces the items whenever they are demanded and promises a certain lead time. Therefore, the retailer has the choices to have the shortage or not during the promised lead time period. This paper investigates different situations where the supplier promises the lead time and permissible delay in payments under the circumstances of retailers choice to have the shortages or not. Finally, numerical examples along with sensitivity analysis are presented to illustrate the proposed model.

Spectroscopic ellipsometry and multiphonon Raman spectroscopic study of excitonic effects in ZnO films

The optical properties and room temperature excitonic features of rf-sputtered ZnO films on Si substrates are studied using spectroscopic ellipsometry and multiphonon Raman scattering. The complex dielectric function e(E) = e1(E) + ie2(E) in the spectral region of 1.3 to 5.5 eV is measured using variable-angle spectroscopic ellipsometry and a Tauc-Lorentz multi-oscillator model is employed to fit the lineshape of the dielectric function. The values of the refractive index of the as-deposited and annealed samples are obtained. Excitonic features in the dielectric function are observed after thermal annealing of the films. Multiphonon Raman spectra up to 7 orders of the longitudinal-optic phonon mode are observed. The matching of the outgoing resonance condition with the exciton energy indicates a strong exciton-phonon coupling. The shape of the dielectric function as well as the intensities and widths of the multiphonon lines suggest the role of both discrete and continuum excitons in describing the optica...

EPQ Model with Product Stewardship Approach

From the past few decades, most of the researchers concentrate on recycling of consumer goods to reduce the impact on environment and health, but now it is time to change our basic approach. In this research paper, we elaborate a nascent issue of product stewardship. Economic production model (EPQ) is a production model in which production occur in a time cycle to fulfill the demand. The proposed model we consider a basic EPQ model with all basic setup and product stewardship. In this paper, we investigate a complete and simple elucidation of product stewardship in a lucid manner which corroborated with many illustrations to convey the intend theme. In this proposed model total cost is calculated with convexity and sensitivity analysis.

Supply Chain Model with Two Storage Facility for Stock Dependent Demand Incorporating Learning and Inflationary Effect under Crisp and Fuzzy Environment

In this paper, a supply chain model with power form stock-dependent demand rate is developed, incorporating the effect of learning and inflationary environment. In order to bring their research closer to reality, all the cost parameters involved in the model are considered fuzzy in nature. The demand rate is assumed to be a polynomial form of current inventory level in Own-warehouse. To display the items, retailer has one warehouse of finite capacity, treated as own warehouse OW and may hire another warehouse of large capacity, treated as rented warehouse RW to storage the excess inventory. Learning effect is incorporated on retailers selling price, purchasing cost, part of holding cost, deterioration cost and ordering cost. Proposed model is illustrated with some numerical example along with sensitivity analysis of parameters.