MULTI-ITEM SHELF-SPACE ALLOCATION OF BREAKABLE ITEMS VIA GENETIC ALGORITHM

MAITI, MANAS KUMAR,MAITI, MANORANJAN 한국전산응용수학회 2006 Journal of applied mathematics & informatics Vol.20 No.1

A general methodology is suggested to solve shelf-space allocation problem of retailers. A multi-item inventory model of breakable items is developed, where items are either complementary or substitute. Demands of the items depend on the amount of stock on the showroom and unit price of the respective items. Also demand of one item decreases (increases) due to the presence of others in case of substitute (complementary) product. For such a model, a Contractive Mapping Genetic Algorithm (CMGA) has been developed and implemented to find the values of different decision variables. These are evaluated to have maximum possible profit out of the proposed system. The system has been illustrated numerically and results for some particular cases are derived. The results are compared with some other heuristic approaches- Simulated Annealing (SA), simple Genetic Algorithm (GA) and Greedy Search Approach (GSA) developed for the present model.

Design of Single Cell Membrane Shape and Array Configuration for MEMS Based Micromachined Ultrasonic Sensor to Improve the Performance: A Three Dimensional Model Characterization

Reshmi Maity,N. P. Maity,Srinivasa Rao Karumuri,Girija Sravani,K. Guha 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

The output acoustic energy of a capacitive micromachined ultrasonic transducer (CMUT) can be enhanced by adjusting its membrane structure. In this paper three dissimilar membranes shapes of CMUT: circular, rectangular and hexagonal, were aimed and 3D finite element method simulated using adaptive meshing technique. The displacement as well as strain and stress outputs for a single membrane and an array of four membranes on a single substrate were obtained. The simulated results are supported by analytical modeling. A static bias of 40 V and a signal of amplitude 100 mV are employed. A pressure of 8603.98 N/m 2 resulting in a force of 16.894 μN was applied at the membrane. Fixtures were provided on every possible face of the structure except the face 1 (membrane). The outcomes showed that the membrane displacement is highest for a circular geometry under same uniform pressure and area of vibration. Moreover as the distance between the elemental membranes increases the displacement decreases for circular and hexagonal membranes while the reverse behavior is observed for rectangular membranes.

Fringing Capacitive Effect of Silicon Carbide Based Nano-Electro-Mechanical-System Micromachined Ultrasonic Transducers: Analytical Modeling and FEM Simulation

Reshmi Maity,N. P. Maity,K. Srinivasa Rao,Girija Sravani,K. Guha,S. Baishya 한국전기전자재료학회 2019 Transactions on Electrical and Electronic Material Vol.20 No.5

This paper models the fringing fi eld eff ects in a capacitive micromachined ultrasonic transducer (CMUT) structure for determining the sensitivity of the device. CMUT is used as a medical imaging component which can be an important module for sustainable healthcare system. The capacitance value of the device is evaluated based on Younes Ataiiyan’s method. To determine the equivalent capacitance of the device, the capacitances of the membrane, gap and silicon nitride insulating layer are associated in series. Mason’s modeling techniques are used to evaluate the membrane displacement. Circular membrane approximation model has been considered. Eff ects of the variation in membrane thickness, gap separation, and membrane radius on membrane displacement are investigated. The analytical prediction has been validated with the finite element method simulation results through PZFlex. Three dimensional modeling is carried out to accurately capture the characteristic behavior of the device. The agreements of both results are excellent which verifi es that fringing field effects exist in the device operation.

Effects of Hafnium Oxide on Surface Potential and Drain Current Models for Subthreshold Short Channel Metal–Oxide–Semiconductor-Field-Effect-Transistor

N. P. Maity,Reshmi Maity,Subir Dutta,Subhasish Deb,K. Girija Sravani,K. Srinivasa Rao,S. Baishya 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.3

Surface potential and drain current models for a physically based double halo metal–oxide–semiconductor-fi eld-eff ect-transistor(MOSFET) are reported. The proposed models have been established in sub-threshold mode of MOSFET operation. The depletion layer depth used in the pseudo two dimensional Poisson’s equation comprises the effect of two symmetrical pocket implantations at both the ends of the channel region. In this effort, improvement in the investigation is brought in by taking lateral asymmetric channel owing to non-uniform doping. The conventional silicon-dioxide (SiO2) material is replaced with a promising high-k dielectric material hafnium oxide (HfO2) to analyze the surface potential and drain current models. Analytical results have been compared using Synopsys technology computer aided design (TCAD). Excellent conformities between the analytical models and simulations are observed.

Design of a Non-uniform Serpentine Asymmetric Cantilever RF-MEMS Shunt Capacitive Switch for RADAR Applications

Ch. Gopichand,Reshmi Maity,N. P. Maity,K. Srinivasa Rao,Koushik Guha,Santanu Maity,Ameen Eisnawi 한국전기전자재료학회 2020 Transactions on Electrical and Electronic Material Vol.21 No.4

This paper presents the design and simulation of Cantilever type RF-MEMS Capacitive shunt switch with meanders and perforations. The main objective of this paper is to reduce the pull-in voltage and increases isolation of the proposed switch. Electro-mechanics and Solid-mechanics are used to simulate the proposed switch by using COMSOL Multiphysics software. The capacitance, switching time, stress analysis are calculated and compare both theoretical and simulation results of the proposed switch. By varying diff erent beam thickness, materials, an air gap between the beam and signal line to calculate spring constant and pull-in voltage. The proposed switch having pull-in voltage is 1.371 V, the dielectric material Si 3 N 4 is to improve the capacitance analysis of the switch. The up and downstate capacitance is 7.073 fF, 1.259 pF. The RF performance is simulated by using Ansoft HFSS tool, the switch performs at low frequencies at 1–4 GHz range. The return (S 11 ) and insertion loss (S 12 ) of the proposed switch is − 30 dB, − 0.0516 dB and the switch having good isolation (S 21 ) is − 37.5 dB at 1.5 GHz frequency. The switch is suitable for radar and satellite communication applications.

Low Pull-in-Voltage RF-MEMS Shunt Switch for 5G Millimeter Wave Applications

P. Ashok Kumar,K. Srinivasa Rao,B. Balaji,M. Aditya,N. P. Maity,Reshmi Maity,Santanu Maity,Ameen El Sinawi,Koushik Guha,K. Girija Sravani 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6

RF MEMS switches have been employed in many commercial and defense applications due to their high potentiality at microwave and millimeter wave frequencies. In this paper, an RF MEMS shunt switch is designed with perforations and without perforations and simulated using iterative meanders for millimeter wave 5G applications. The proposed iterative meander offers a low spring-constant of 0.68 N/m and reduces the pull-in-voltage upto 1.8 V. The proposed perforated switch design is more reliable which operates with less transition time of 11.2 μs with a quality factor of 1.69. The switch possesses high capacitance ratio of 63. During ON condition, the switch shows low insertion loss of − 0.24 dB at 41 GHz and high isolation of − 46.7 dB at 38 GHz. The performance of the switch is analyzed by simulating it using COMSOL Multiphysics 5.2v (FEM tool). The obtained simulation results shows close approximation with the theoretical results and the switch is efficiently used for 5G millimeter wave applications.

On Semirings which are Distributive Lattices of Rings

Maity, S.K. Department of Mathematics 2005 Kyungpook mathematical journal Vol.45 No.1

We introduce the notions of nilpotent element, quasi-regular element in a semiring which is a distributive lattice of rings. The concept of Jacobson radical is introduced for this kind of semirings.

Synthetic, crystallographic and electrochemical studies of thienyl-substituted corrole complexes of copper and cobalt

Maiti, Nilkamal,Lee, Junseong,Kwon, Seong Jung,Kwak, Juhyoun,Do, Youngkyu,Churchill, David G. Elsevier 2006 Polyhedron Vol.25 No.7

<P><B>Graphical abstract</B></P><P>Novel thienyl <I>meso</I>-substituted 5,10,15-tris(2-thienyl)corrole and 5,10,15-tris(3-thienyl)corrole and their copper and cobalt complexes have been prepared and fully characterized. Single-crystal X-ray diffraction studies for copper(5,10,15-tris(2-thienyl)corrole) and both cobalt(5,10,15-tris(thienyl)corrole)(Py)<SUB>2</SUB> isomers were obtained. CV data supports monomer redox, devoid of dinuclear products arising from intermolecular C–C coupling observed in related systems.</P><ce:figure></ce:figure> <P><B>Abstract</B></P><P>The TFA-catalyzed condensation of 5-(thienyl)dipyrromethane with thiophene carboxaldehyde allows for the formation of the thienyl <I>meso</I>-substituted 5,10,15-tris(2-thienyl)corrole H<SUB>3</SUB>(T2TC) (<B>1</B>) and the 5,10,15-tris(3-thienyl)corrole H<SUB>3</SUB>(T3TC) (<B>2</B>). These ligands undergo metalation with copper and cobalt acetate to yield the four respective metallocorroles. Single-crystal X-ray crystallographic solutions for Cu(T2TC) (<B>3</B>), Co(T2TC)(Py)<SUB>2</SUB> (<B>5</B>) and Co(T3TC)(Py)<SUB>2</SUB> (<B>6</B>) have been obtained, confirming the direct pyrrole–pyrrole link and axial pyridine groups in the case of the cobalt structures. Cyclic voltammetry data indicated the 2-thienyl derivatives are more difficult to oxidize when compared to trispentafluorophenyl corroles (TPFC). Both metal complex isomers are comparably stable towards the formation of dinuclear products resulting from intermolecular C–C coupling. Soret bands for both ligands and complexes have been obtained and variable temperature <SUP>1</SUP>H NMR studies (−50–60°C) for <B>3</B> and <B>4</B> reveal a fluxional rotational behavior for the three thienyl substituents believed to impart a less electron withdrawing effect on the corrole core, opposed to the TPFC’s.</P>

Preparation and characterization of ibuprofen-loaded alginate microspheres using ethylenediamine as a crosslinker

Maiti, Sabyasachi,Sa, Biswanath Kyung Hee Oriental Medicine Research Center 2008 Oriental pharmacy and experimental medicine Vol.8 No.2

In this study, ionotropic gelation method was used for the preparation of ibuprofen-loaded calcium alginate (CALG) and ethylenediamine (EDA) treated calcium alginate (EDA-CALG) microspheres. The effect of EDA-treatment on drug entrapment efficiency, particle size, morphology, swelling behavior and in vitro release characteristics of the microspheres was investigated by varying its concentration from 0.5 to 2% (v/v). The reduction in drug entrapment efficiency by a maximum of 44.60% was noted for EDA-CALG microspheres compared to untreated CALG microspheres. The particle size and swelling index of EDA-CALG microspheres were reduced with increasing EDA concentration. All the microspheres were observed to retain their spherical shapes with rough surfaces. EDA-CALG microspheres prepared using 1% and 2% v/v EDA, released almost all of its content within 7 h in pH 6.8 phosphate buffer, however, CALG microspheres were found to release the same within 3 h. The intensity of melting endothermic peak of ibuprofen reduced significantly at lower drug load as experienced from DSC thermograms. The FT-IR spectrum of pure ibuprofen, ibuprofen-loaded CALG and EDA-CALG microspheres showed the characteristic band of C = O stretching vibration of ibuprofen. Hence, this study revealed that EDA can be employed for the preparation of ibuprofen-loaded CALG microspheres to retard the drug release to some extent.

Self-Size-Limiting Nanoscale Perforation of Graphene for Dense Heteroatom Doping

Maiti, Uday Narayan,Thapa, Ranjit,Lim, Joonwon,Li, Dong Jun,Kim, Kwang Ho,Kim, Sang Ouk American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.46

<P>A scalable and controllable nanoscale perforation method for graphene is developed on the basis of the two-step thermal activation of a graphene aerogel. Different resistance to the thermal oxidation between graphitic and defective domains in the weakly reduced graphene oxide is exploited for the self-limiting nanoscale perforation in the graphene basal plane via selective thermal degradation of the defective domains. The resultant nanoporous graphene with a narrow pore-size distribution addresses the long-standing challenge for the high-level doping of graphene with lattice-mismatched large-size heteroatoms (S and P). Noticeably, this novel heteroatom doping strategy is demonstrated to be highly effective for oxygen reduction reaction (ORR) catalysis. Not only the higher level of heteroatom doping but also favorable spin and charge redistribution around the pore edges leads to a strong ORR activity as supported by density functional theory calculations.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-46/acsami.5b08391/production/images/medium/am-2015-08391s_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b08391'>ACS Electronic Supporting Info</A></P>