Neural Network Based Thermal Analysis of Ultradeep Submicron Digital Circuit Design

With a reduction in transistor dimensions to the nanoscale regime of 45 nm or less, quantum mechanical effects begin to reveal themselves and have an impact on key device performance parameters. As a result, in order to develop simulation tools that can be used for the design of nanoscale transistors in the future, new theories and modelling methodologies must be developed that properly and effectively capture the physics of quantum transport. An artificial neural network (ANN) is used in this paper to examine nanoscale CMOS circuits and predict the performance parameters of CMOS-based digital inverters for a temperature range of 300 K to 400 K. The training algorithm included three hidden layers with sizes of 20, 10, and 8, as well as a function fitting ANN with Bayesian Backpropagation Regularization. Further, simulation through HSPICE using Predictive Technology Model (PTM) nominal parameters has been done to compare with ANN (trained using an analytical model) results. The obtained results lie within the acceptable range of 1%-10%. Moreover, it has also been demonstrated that the ANN simulation provides a speed improvement of around 85 % over the HSPICE simulation, and that it can be easily integrated into software tools for designing and simulating complicated CMOS logic circuits.     

Traditional cooked vegetable dishes as important sources of ascorbic acid and beta-carotene in the diets of Indian urban and rural families

BACKGROUND: Fresh vegetable produce is abundant during the winter season in Punjab. It is an important source of vitamins and minerals in the Punjabi diet, but the availability of ascorbic acid and beta-carotene from the vegetables is altered to varying degrees when they are subjected to traditional household processing methods. OBJECTIVE: To determine the importance of traditional cooked vegetable dishes as sources of ascorbic acid and beta-carotene among urban and rural families during the winter. METHODS: Information about vegetable consumption, storage, and cooking practices was collected from 60 families, 30 each from urban and rural areas of Ludhiana District, Punjab, India. Samples of the common cooked vegetable dishes were prepared in the laboratory by methods ascertained from the survey and analyzed for ascorbic acid and beta-carotene. RESULTS: The average total daily per capita consumption of vegetables by urban and rural families was 411.7 and 365.9 g, respectively. Cooked vegetable dishes provided 68.7% of the total vegetable intake for urban families and 85.0% for rural families. On average, the edible portion constituted 78.9% of the weight of the vegetables. Ten cooked vegetable dishes that were most frequently consumed by the families (mustard saag, potato-spinach, potato-fenugreek, potato-brinjal, potato-cauliflower, potato-capsicum, potato-carrots, potato-beans, potato-peas, and cabbage-peas) were selected for preparation in the laboratory and nutritional analysis. The average concentrations of ascorbic acid and beta-carotene in the cooked vegetable dishes were 46.0 mg/100 g and 794.2 microg/100 g fresh weight, respectively. The percentage losses of ascorbic acid and beta-carotene during preparation and cooking were 26.1% and 25.9%, respectively. CONCLUSIONS: For adult Indian men and women, the recommended dietary allowance of ascorbic acid is 40 mg, and that of beta-carotene is 2,400 microg. Cooked vegetable dishes provided 269.9% and 77.5% of the recommended dietary allowances of ascorbic acid and beta-carotene, respectively, indicating that these dishes are good sources of these nutrients in the diets of both urban and rural families during the winter season.     

Texture prediction during deep frying: A mechanistic approach

A framework for fundamental physics-based prediction of texture was developed whereby changes in Young’s modulus in potato strips during frying could be predicted by combining modulus changes with temperature and moisture with predictions of the latter from fundamental physics-based process model. Moisture and temperature dependence of Young’s modulus was obtained from experiment. Process model for frying was based on multiphase porous media based transport equations. Effective value of Young’s modulus for a potato strip was obtained from local values of modulus predicted by the model through homogenization. The predictions were validated using measured Young’s modulus during frying. Such a model-based prediction providing insight into texture development during a frying process (both as function of time as well as spatially) within the potato strip will be difficult to achieve from direct experimentation alone. Precise effects of increased sample size and reduced oil temperature in slowing down the texture development are shown. Since the model is physics-based, the prediction framework can be extended to processes other than frying, allowing fundamental-based quality prediction in general.     

Polymer nanocomposite‐based shielding against diagnostic X‐rays

Lead is commonly used in medical radiology departments as a shielding material. Lead‐based protective materials are also used by clinical personnel during X‐ray image‐guided interventional radiology (IVR) procedures. However, lead is extremely toxic and prolonged exposure to it can result in serious health concerns. Polymer composites, on the other hand, can be designed to be lead‐free in addition to being lightweight, conformable, cost effective, and potentially capable of significantly attenuating X‐rays. Nanomaterials have unique material properties that can be exploited to develop novel lead‐free radiation‐protection materials. In this study, polydimethylsiloxane (PDMS) nanocomposites were fabricated using different weight percentages (wt %) of bismuth oxide (BO) nanopowder. The attenuation properties of the nanocomposites were characterized using diagnostic X‐ray energies from 40 to 150 kV tube potential and were compared to the attenuation characteristics of 0.25‐mm‐thick pure lead sheet. The PDMS/BO nanocomposite (44.44 wt% of BO and 3.73‐mm thick) was capable of attenuating all the scattered X‐rays generated at a tube potential of 60 kV, which is the beam energy commonly employed in IVR. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2013     

Impact of pixel size on mapping surface water in subsolar imagery

We observed surface water in a wetland, imaging in the subsolar or specular direction the exceptionally bright specular reflection of sunlight at a ground resolution of 0.3 m. We then simulated ground resolutions between 1.7 m and 1.2 km through aggregation of the 0.3 m pixels. Contrary to the expectations of some of our colleagues in the wetlands community, for these data, the accuracy of spectral mixture analysis (SMA) estimates of surface water increases as pixel ground footprint size increases. Our results suggest that regional to global scale assessments of flooded landscapes and wetlands that do not involve issues requiring 1 m resolution per se may be addressed with acceptable accuracy by applying SMA techniques to low resolution imagery. Our results indicate within-pixel estimates of surface water area derived from data measured by subsolar viewing sensors with large ground pixel footprints, such as satellite POLarization and Directionality of Earth Radiance (POLDER) data, may be highly accurate under strong surface wind conditions.     

Designing a Fault-tolerant Fully-Chained Combining Switches Multi-stage Interconnection Network with Disjoint Paths

Multi-stage Interconnection Networks (MINs) are designed to achieve fault-tolerance and collision solving by providing a set of disjoint paths. Ching-Wen Chen and Chung-Ping Chung had proposed a fault-tolerant network called Combining Switches Multi-stage Interconnection Network (CSMIN) and an inaccurate algorithm that provided two correct disjoint paths only for some source-destination pairs. This paper provides a more comprehensive and accurate algorithm that always generate correct routing-tags for two disjoint paths for every source-destination pair in the CSMIN. The 1-fault tolerant CSMIN causes the two disjoint paths to have regular distances at each stage. Moreover, our algorithm backtracks a packet to the previous stage and takes the other disjoint path in the event of a fault or a collision in the network. Furthermore, to eliminate the backtracking penalties of CSMIN, we propose a new design called Fault-tolerant Fully-Chained Combining Switches Multi-stage Interconnection Network (FCSMIN). It has similar characteristics of 1-fault tolerance and two disjoint paths between any source-destination pair, but it can tolerate only one link or switch fault at each stage without backtracking. Our simulation and comparative analysis result shows that FCSMIN has added advantages of destination-tag routing, lower hardware costs, strong reroutability, lower preprocessing overhead, and higher fault-tolerance power in comparison to CSMIN.     

Insights into the folding pathway of the Engrailed Homeodomain protein using replica exchange molecular dynamics simulations

Protein folding studies were carried out by performing microsecond time scale simulations on the ultrafast/fast folding protein Engrailed Homeodomain (EnHD) from Drosophila melanogaster. It is a three-helix bundle protein consisting of 54 residues (PDB ID: 1ENH). The positions of the helices are 8-20 (Helix I), 26-36 (Helix II) and 40-53 (Helix III). The second and third helices together form a Helix-Turn-Helix (HTH) motif which belongs to the family of DNA binding proteins. The molecular dynamics (MD) simulations were performed using replica exchange molecular dynamics (REMD). REMD is a method that involves simulating a protein at different temperatures and performing exchanges at regular time intervals. These exchanges were accepted or rejected based on the Metropolis criterion. REMD was performed using the AMBER FF03 force field with the generalised Born solvation model for the temperature range 286-373 K involving 30 replicas. The extended conformation of the protein was used as the starting structure. A simulation of 600 ns per replica was performed resulting in an overall simulation time of 18 μs. The protein was seen to fold close to the native state with backbone root mean square deviation (RMSD) of 3.16 ?. In this low RMSD structure, the Helix I was partially formed with a backbone RMSD of 3.37 ? while HTH motif had an RMSD of 1.81 ?. Analysis suggests that EnHD folds to its native structure via an intermediate in which the HTH motif is formed. The secondary structure development occurs first followed by tertiary packing. The results were in good agreement with the experimental findings.