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81.
Combination heating of food using microwave and jet impingement has been simulated by coupling Maxwell’s equations of electromagnetics with energy equation and using experimentally measured heat transfer coefficient values for jet impingement in a novel domestic oven. Transient food temperatures from the model and experiment for each separate heating mode and their combination revealed the characteristic nature of each of the heating modes. Contour plots of temperature show that with combination heating, surface can be heated faster (for crispness) and edge over-heating can be partially avoided. Measures of non-uniformity in temperatures in the heated food are developed using coefficient of variation and middle 80-percentile range as the parameters. Using these measures, it is shown that combination heating leads to more uniform heating, without compromising the speed or convenience. A 22–30% increase in uniformity has been observed for combination microwave–jet impingement heating over microwave-only heating. Jet impingement is a good complement to microwave heating as it has different spatial and time variation of heating rates. During the initial period, jet impingement dominates over microwave heating near the surface, with microwave heating being more significant in the interior. At later times, the roles switch with microwaves becoming more dominant on the surface while jet impingement takes a more significant role in heating the interior of the food. These findings should help the product, process and equipment designer achieve the balance between speed and uniformity of heating in a more precise manner. 相似文献
82.
Priyanka Singh Shailesh N. Sharma N. M. Ravindra 《JOM Journal of the Minerals, Metals and Materials Society》2010,62(6):15-24
An overview of the applications of porous silicon (PS) thin films, as antireflection coatings (ARC) in silicon solar cells and transducers in biosensors, is presented. The reflectance spectra of PS films have been compared with other conventional ARCs (such as SiNx TiO2/MgF2 and ZnS), and optimal PS ARC with minimum reflectance has been obtained. The implementation of PS into an industrially compatible screen-printed (SP) solar cell by both the electrochemical etching (ECE) and chemical etching (CE) methods are reviewed. Porous silicon films, formed via ECE for short anodization times, on textured n+ emitter ofc-Si solar cell having SP front and back contacts, lead to improvements in the performance of solar cells and demonstrate their viability in industrial applications. 相似文献
83.
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85.
Sayantan Sil Arka Dey Soumi Halder Joydeep Datta Partha Pratim Ray 《Journal of Materials Engineering and Performance》2018,27(6):2649-2654
Here we have approached the plausible use of CuFeS2 nanocomposite as an acceptor in organic–inorganic hybrid solar cell. To produce CuFeS2 nanocomposite, hydrothermal strategy was employed. The room-temperature XRD pattern approves the synthesized material as CuFeS2 with no phase impurity (JCPDS Card no: 37-0471). The elemental composition of the material was analyzed from the TEM-EDX data. The obtained selected area electron diffraction (SAED) planes harmonized with the XRD pattern of the synthesized product. Optical band gap (4.14 eV) of the composite from UV–Vis analysis depicts that the synthesized material is belonging to wide band gap semiconductor family. The HOMO (? 6.97 eV) and LUMO (? 2.93 eV) positions from electrochemical study reveal that there is a possibility of electron transfer from MEH-PPV to CuFeS2. The optical absorption and photoluminescence spectra of MEH-PPV:CuFeS2 (donor:acceptor) composite were recorded sequentially by varying weight ratios. The monotonic blue shifting of the absorption peak position indicated the interaction between donor and acceptor materials. The possibility of electron transfer from donor (MEH-PPV) to acceptor (CuFeS2) was approved with photoluminescence analysis. Subsequently, we have fabricated a hybrid solar cell by incorporating CuFeS2 nanocomposite with MEH-PPV in open atmosphere and obtained 0.3% power conversion efficiency. 相似文献
86.
Alam Ashraful Hariyanto Bambang Ullah Hayat Salin Krishna R. Datta Avishek 《SILICON》2021,13(9):3153-3162
Silicon - Silicon (Si) plays an important role in mitigating adverse effects of various biotic and abiotic stresses including drought. Polyhouse experiment was conducted to evaluate the effects of... 相似文献
87.
A. Datta S. Dutta S.K. Pal R. Sen 《Journal of Materials Processing Technology》2013,213(12):2339-2349
Tool condition monitoring by machine vision approach has been gaining popularity day by day since it is a low cost and flexible method. In this paper, a tool condition monitoring technique by analysing turned surface images has been presented. The aim of this work is to apply an image texture analysis technique on turned surface images for quantitative assessment of cutting tool flank wear, progressively. A novel method by the concept of Voronoi tessellation has been applied in this study to analyse the surface texture of machined surface after the creation of Voronoi diagram. Two texture features, namely, number of polygons with zero cross moment and total void area of Voronoi diagram of machined surface images have been extracted. A correlation study between measured flank wear and extracted texture features has been done for depicting the tool flank wear. It has been found that number of polygons with zero cross moment has better linear relationship with tool flank wear than that of total void area. 相似文献
88.
In the present work, we report the preparation of PLZT thin films in pure perovskite phase by RF magnetron sputtering without
external substrate heating and their integration with micro-cantilevers. The ‘lift-off’ process for patterning different layers
of a micro-cantilever including PLZT, Pt/Ti and Au/Cr was employed. The basic requirement of lift-off process is that the
deposition temperature should not exceed 200°C otherwise photoresist will burn out. Therefore, one of the aims of the present
work was to prepare PLZT film at lower deposition temperatures, which can be subsequently annealed to form pure perovskite
phase. This also strongly favours the incorporation of ‘lift-off’ process for patterning in the complete process flow. As
no external substrate heating was required in the deposition of PLZT film, this objective has been successfully accomplished
in the present work. The ‘lift-off’ process has been successfully adopted for patterning the composite layers of PLZT/Pt/Ti
and Au/Cr using thick positive photo-resist (STR-1045). Different types of cantilever beams incorporating PLZT films have
been successfully fabricated using ‘lift-off’ process and bulk micromachining technology. The proposed process can be advantageously
applied for the fabrication of various MEMS devices. 相似文献
89.
Optimal Dynamic Monitoring Network Design and Identification of Unknown Groundwater Pollution Sources 总被引:2,自引:2,他引:0
The identification of unknown pollution sources is a prerequisite for designing of a remediation strategy. In most of the
real world situations, it is difficult to identify the pollution sources without a scientifically designed efficient monitoring
network. The locations of the contaminant concentration measurement sites would determine the efficiency of the unknown source
identification process to a large extent. Therefore coupled and iterative sequential source identification and dynamic monitoring
network design framework is developed. The coupled approach provides a framework for necessary sequential exchange of information
between monitoring network and source identification methodology. The preliminary identification of unknown sources, based
on limited concentration data from existing arbitrarily located wells provides the initial rough estimate of the source fluxes.
These identified source fluxes are then utilized for designing an optimal monitoring network for the first stage. Both the
monitoring network and source identification process is repeated by sequential identification of sources and design of monitoring
network which provides the feedback information. In the optimal source identification model, the Jacobian matrix which is
the determinant for the search direction in the nonlinear optimization model links the groundwater flow-transport simulator
and the optimization method. For the optimal monitoring network design, the integer programming based optimal design model
requires as input, simulated sets of concentration data. In the proposed methodology, the concentration measurement data from
the designed and implemented monitoring network are used as feedback information for sequential identification of unknown
pollution sources. The potential applicability of the developed methodology is demonstrated for an illustrative study area. 相似文献
90.
Suresh Bhalla Praveen Kumar Ashok Gupta Tushar K. Datta 《Canadian Metallurgical Quarterly》2009,22(4):373-382
The electromechanical impedance technique employs surface-bonded lead zirconate titanate piezoelectric ceramic patches as impedance transducers for structural health monitoring and nondestructive evaluation. The patches are bonded to the monitored structures using finitely thick adhesive bond layer, which introduces shear lag effect, thus invariably influencing the electromechanical admittance signatures. This paper presents a new simplified impedance model to incorporate shear lag effect into electromechanical admittance formulations, both one-dimensional and two-dimensional. This provides a closed-form analytical solution of the inverse problem, i.e. to derive the true structural impedance from the measured conductance and susceptance signatures, thus an improvement over the existing models. The influence of various parameters (associated with the bond layer) on admittance signatures is investigated using the proposed model and the results compared with existing models. The results show that the new model, which is far simpler than the existing models, models the shear lag phenomenon reasonably well besides providing direct solution of a complex inverse problem. 相似文献