Showing papers by "Jadavpur University published in 1991"
TL;DR: In this article, the inventory replenishment policy over a fixed planning period for a deteriorating item having a deterministic demand pattern with a linear trend and shortages is considered, and the number of reorders, the interval between two successive reorders and the shortage intervals over a finite time-horizon are all determined in an optimal manner so as to keep the average system cost to a minimum.
Abstract: We consider here the inventory replenishment policy over a fixed planning period for a deteriorating item having a deterministic demand pattern with a linear trend and shortages. The number of reorders, the interval between two successive reorders and the shortage intervals over a finite time-horizon are all determined in an optimal manner so as to keep the average system cost to a minimum. One numerical example illustrates how the procedure works. The counterpart of this example in the no-shortage case is also given. The effects of variation in the deterioration rate on the optimal policy are also indicated with numerical examples.
197 citations
01 Jan 1991
TL;DR: In this paper, a direct power flow solution technique for radial distribution networks has been proposed, where a unique branch and node numbering scheme have been proposed to achieve storage and computational economy.
Abstract: The paper reports on a direct power flow solution technique for radial distribution networks. The special topology of distribution networks has been fully exploited to make direct solution possible. A unique branch and node numbering scheme has been proposed to achieve storage and computational economy. Composite load characteristics can be easily modelled. The method developed has been extended for meshed and unbalanced distribution networks. In both cases, modifications required are few and the advantages obtained in balanced radial networks in respect of storage and computational requirements have been preserved. The proposed method has been successfully applied to the solution of a number of practical distribution networks.
182 citations
TL;DR: In this article, an attempt has been made to investigate the effects of inflation and time-value of money on an inventory model with linear time-dependent demand rate, where shortages are allowed in this model.
167 citations
TL;DR: In this article, a new formulation of garnet-biotite Fe−Mg exchange thermometer was developed through statistical regression of the reversed experimental data of Ferry and Spear.
Abstract: A new formulation of garnet-biotite Fe−Mg exchange thermometer has been developed through statistical regression of the reversed experimental data of Ferry and Spear. Input parameters include available thermo-chemical data for quaternary Fe−Mg−Ca−Mn garnet solid solution and for excess free energy terms, associated with mixing of Al and Ti, in octahedral sites, in biotite solid solution. The regression indicates that Fe−Mg mixing in biotite approximates a symmetrical regular solution model showing positive deviation from ideality withW
FeMg
bi
=1073±490 cal/mol. ΔH
r
and ΔS
r
for the garnet-biotite exchange equilibrium were derived to be 4301 cal and 1.85 cal respectively. The resultant thermometer gives consistent results for rocks with a much wider compositional range than can be accommodated by earlier formulations.
151 citations
TL;DR: A methanolic fraction from an extract of Bryophyllum pinnatum leaves was found to possess significant anti-ulcer activity in nine different experimental animals models and enhancement of the healing process was found in acetic acid-induced chronic gastric lesions in rats.
101 citations
TL;DR: A chloroform-soluble fraction from Calotropis procera roots showed significant dose-related antiinflammatory activity in rats using the pharmacologic models of carrageenin-induced pedal oedema, cotton pellet granuloma and formaldehyde-induced arthritis.
91 citations
TL;DR: In this article, the effect of the presence of Zn and Fe3+ in spinel on the proposed grid is evaluated and it is shown that bulk composition (XFe and Zn) exerts greater control on the stability of spinel + quartz than fo2.
Abstract: Spinel-quartz-cordierite and spinel-quartz are found as relic prograde assemblages in Fe-rich granulites from the Araku area, Eastern Ghats belt, India. Subsequent reactions produced orthopyroxene + sillimanite in the former association and garnet + sillimanite in the latter. The first reaction is univariant in the FMAS system, but is trivariant in the present case because of the presence of Zn and Fe3+ in spinel. The second reaction also has high variance because of Zn and Fe3+, but also because of the presence of Ca in garnet. Thermobarometry shows that the metamorphic conditions were approximately 950° C and 8.5 kbar and the fo2 was near the NNO buffer. In Fe-rich bulk compositions and low-P-high-T conditions of metamorphism, two of the univariant reactions around the invariant point [Sa], namely (Sa, Hy) and (Sa, Cd), change topology due to reverse partitioning of Fe-Mg between coexisting garnet and spinel. An alternative partial petrogenetic grid in the system FMAS is constructed for such conditions and is applied satisfactorily to several sapphirine-free spinel granulites. It is shown that bulk composition (XFe and Zn) exerts greater control on the stability of spinel + quartz than fo2. The effect of the presence of Zn and Fe3+ in spinel on the proposed grid is evaluated. Reaction textures in the Araku spinel granulites can be explained from the petrogenetic grid as due to near-isobaric cooling.
83 citations
TL;DR: In this article, the authors tried to explain why duopolistic firms would like to enter cooperative R and D venture even when they would act non-cooperatively in the product market.
66 citations
TL;DR: In this paper, the alteration of ilmenite by leaching is shown to be a continuous process, proceeding from leached ilmenites through pseudorutile to leucoxene.
62 citations
TL;DR: The present observations establish the efficacy of the chloroform extract in the exudative, proliferative and chronic stages of inflammation.
58 citations
TL;DR: In this article, a Harris-Todaro type structure was developed where industry uses agricultural product as an input and it was shown that in this case an urban employment subsidy will increase total employment unambiguously.
TL;DR: In this article, an economic order quantity (EOQ) model is developed for an item with a deterministic time-dependent demand pattern with a linear (positive) trend, and the model is solved allowing either no shortage or a shortage in the inventory.
Abstract: An economic order quantity (EOQ) model is developed for an item with a deterministic time-dependent demand pattern with a linear (positive) trend. It is assumed that the inventory is replenished at a uniform rate. The model is solved allowing either no shortage or a shortage in the inventory. The procedures of applying the results in practical cases are illustrated with the help of numerical examples.
01 Jul 1991
TL;DR: A microprocessor-based automatic position control scheme has been designed for controlling the azimuth angle of an optimally tilted photovoltaic flat type solar panel or a cylindrical parabolic reflector to get the illuminating surface appropriately positioned for the collection of maximum solar irradiance as discussed by the authors.
Abstract: A microprocessor-based automatic position control scheme has been designed for controlling the azimuth angle of an optimally tilted photovoltaic flat type solar panel or a cylindrical parabolic reflector to get the illuminating surface appropriately positioned for the collection of maximum solar irradiance. The scheme presented results in considerable saving in power and is independent of the geographical location of the site of erection or temporal variations in environmental parameters.
TL;DR: In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced and lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG‐treated EAC cells.
Abstract: The effect of methylglyoxal (MG), ascorbic acid and lactaldehyde has been tested on the in vitro respiration of Ehrlich ascites carcinoma (EAC) cells and several normal and malignant human tissues. Methylglyoxal inhibited the respiration of each type of malignant cell and tissue tested, but it had practically no inhibitory effect on the respiration of any of the normal cells and tissues. Ascorbic acid exhibited a synergistic effect with MG in inhibiting the respiration of all the neoplastic cells. In the presence of lactaldehyde, a catabolite of MG, the inhibitory effect of MG on the respiration of tumor cells was significantly reduced. Lactaldehyde can exert a similar protective effect on the loss of viability and transplantability of MG-treated EAC cells.
TL;DR: In this paper, the inflationary solutions for the Bianchi-IX space-time in presence of a massless scalar field with a flat potential were studied for pure massive strings following the Takabayashi equation of state ρ=(1+w)λ.
Abstract: In this paper the inflationary solutions are studied for the Bianchi-IX space-time in presence of a massless scalar field with a flat potential. Also a class of cosmological solutions of massive strings are obtained following the techniques used by Letelier and Stachel. Some solutions are calculated for pure massive strings following the Takabayashi equation of state ρ=(1+w)λ.
TL;DR: In this paper, simple and selective spectrophotometric methods for the determination of norfloxacin and nalidixic acid are described. The methods are based on the measurement of the intensity of the orange-red colour produced by the drugs with ferric chloride in dimethylsulphoxide-methanol medium.
Abstract: Simple and selective spectrophotometric methods for the determination of norfloxacin, ciprofloxacin, cinoxacin and nalidixic acid are described. The methods are based on the measurement of the intensity of the orange-red colour produced by the drugs with ferric chloride in dimethylsulphoxide-methanol medium. The methods are highly accurate and have been successfully applied for analysis of bulk drugs and pharmaceutical preparations. The results are in good agreement with the official methods.
TL;DR: In this article, the scaled factorial moments, F q and fractal moments, G q have been measured and their power law variation as a function of size of the pseudorapidity interval has been studied in the central region of the produced charged particles in quasi-central and central collisions.
TL;DR: In this paper, it was shown that the layer segments produced by a set of parallel shear fractures may undergo rotation with separation or rotation with interfacial slip depending upon their geometry, the thickness to length ratio (G T ) of layer-segments and the orientation of fractures are the parameters that could control the rate of rotation versus rate of displacement of layer segments.
TL;DR: Isoglabrachromene, a natural chromenoflavanone, and hexacosanyl caffeate and triacontanyl caffeates, two new esters, have been isolated together with 11 known flavonoids and betulinic acid from the stem bark of Pongamia glabra.
TL;DR: A study has been made of the mineral requirements of Bacillus thuringiensis subsp.israelensis for production of the mosquitocide delta endotoxin, finding the optimum concentrations of K2HOP4, MgSO4.7H2O and CaCO3 for toxin production.
Abstract: A study has been made of the mineral requirements ofBacillus thuringiensis subsp.israelensis for production of the mosquitocide delta endotoxin. The optimum concentrations of K2HOP4, MgSO4.7H2O and CaCO3 for toxin production are 1g/l, 0.3g/l and 1g/l respectively while the elements Fe, Mn, Cu are required at levels of 2 μg/ml, 5 μg/ml and 0.25 μg/ml respectively.
TL;DR: In this paper, X-ray and infrared diffraction studies have been carried out on raw and chemically treated pineapple leaf fiber (PALF) and showed that the degree of crystallinity decreases on treatment with NaOH and NaClO2 solutions, attributed to the conversion of intermediate or semicrystalline regions to amorphous ones and with higher concentration to structural changes.
Abstract: IR and X-ray diffraction studies have been carried out on raw and chemically treated pineapple leaf fiber (PALF). The degree of crystallinity, as found by X-ray diffraction and the crystallinity index as found by infrared methods, decreases on treatment with NaOH and NaClO2 solutions. The decrease of crystallinity with lower concentration of NaOH is attributed to the conversion of intermediate or semicrystalline regions to amorphous ones and with higher concentration to structural changes and with NaClO2 solution to the disorientation caused due to removal of cementing material lignin.
TL;DR: It is shown that if the urban demand for labor is isoelastic or inelastic, creation of urban jobs causes urban unemployment to decline and urban-to-rural migration to take place, and urban job creation always reduces the rate of urban unemployment.
TL;DR: In this paper, the fluorescence of tetrakis(sulfonatophenyl) porphyrin (TPPS) and its photophysics were studied in a number of homogeneous solvents and Triton X-100 micelle.
Abstract: The fluorescence of tetrakis(sulfonatophenyl) porphyrin (TPPS) and its photophysics were studied in a number of homogeneous solvents and Triton X-100 micelle. Enhancement of fluorescence quantum yields are discussed on the basis of polarity and viscosity of the solvents. Rotational correlation times τ R were measured, using fluorescence anisotropy to show rigidization of the TPPS by the local environment of the micelle.
TL;DR: In this paper, the stereoselective intramolecular addition of carbanions derived from the acetylenic amides has been shown to lead to α-methylene-γ-lactam derivatives.
TL;DR: The electrochemical oxidation of some substituted porphyrins and their metal complexes in organic solvent dichloromethane (CH 2 Cl 2 ) leads to the formation of electroactive Porphyrin films which can produce reproducible photovoltage and photocurrent on illumination as discussed by the authors.
TL;DR: Etude de la dependance du rapport diffusivite-mobilite de superreseaux semiconducteurs vis-a-vis du dopage and du champ magnetique as discussed by the authors.
Abstract: Etude de la dependance du rapport diffusivite-mobilite de superreseaux semiconducteurs vis-a-vis du dopage et du champ magnetique. On prend GaAs/AlAs comme exemple
TL;DR: In this article, the mass flow deposition in the Precambrian Chanda Limestone Formation in Adilabad District, Andhra Pradesh, India transcribes carbonate mass flows deposition in an extensional basin within the Godavari rift valley system.
TL;DR: In this article, an attempt was made to study the Einstein relation for the diffusivity-mobility ratio of electrons under magnetic quantization for a new type of III-V superlattice, called the effective mass super-attice by formulating the appropriate magneto-dispersion law and taking the Ga0.86In0.14P0.78Sb0.22/GaAs mass-modulation super-additive superladdiction as an example.
Abstract: An attempt is made to study the Einstein relation for the diffusivity-mobility ratio of electrons under magnetic quantization for a new type of III-V superlattice, called the effective mass superlattice, by formulating the appropriate magneto-dispersion law and taking the Ga0.86In0.14P0.78Sb0.22/GaAs mass-modulation superlattice as an example. It is found that the ratio oscillates with an inverse quantizing magnetic field and increases with increasing electron concentration. The oscillatory spikes are much sharper even in the presence of broadening with large numerical magnitudes for the aforementioned heterostructures in contrast to those obtained for the constituent bulk semiconductors under magnetic quantization.
TL;DR: It is found that the food-conversion efficiency rate of microbial organisms governs the dynamics of such a model and the permanence of the model is shown to operate uniformly in a certain parameter region even though its stability characteristics may be topologically different.
TL;DR: The Upper Proterozoic Kaimur Sandstones in central India are quartz-, sublithic-and lithic-arenites cemented by quartz, illite and hematite as discussed by the authors.