Optimization of thermal interface materials for electronics cooling applications

Thermal interface materials (TIMs) are used in electronics cooling applications to decrease the thermal contact resistance between surfaces in contact. A methodology to determine the optimal volume fraction of filler particles in TIMs for minimizing the thermal contact resistance is presented. The method uses finite element analysis to solve the coupled thermo-mechanical problem. It is shown that there exists an optimal filler volume fraction which depends not only on the distribution of the filler particles in a TIM but also on the thickness of the TIM layer, the contact pressure and the shape and the size of the filler particles. A contact resistance alleviation factor is defined to quantify the effect of these parameters on the contact conductance with the use of TIMs. For the filler and matrix materials considered-platelet-shaped boron nitride filler particles in a silicone matrix-the maximum observed enhancement in contact conductance with the use of TIMs was by a factor of as much as nine.     

2-Nitrobenzaldehyde Thiocarbohydrazone Assisted Precise Extraction Spectrophotometric Method for the Determination of Ruthenium(III) in Alloy and Catalysts

A simple, rapid, selective, sensitive and reliable extractive spectrophotometric method was developed for the determination of ruthenium(III) using 2-nitrobenzaldehyde thiocarbohydrazone (2-NBATCH) as a chromogenic chelating ligand. The ruthenium(III)?2-NBATCH complex is formed in aqueous acetic acid media (0.7 M) containing an organic solvent after 5 min heating on a water bath. The red colored complex is extracted into 1,2-dichloroethane and absorbance is measured at 445 nm against reagent blank. The Beer’s law is obeyed within 1?6 g/mL of ruthenium(III), the optimum concentration range was 2?5 g/mL of ruthenium(III) evaluated by Ringbom’s plot. Molar absorptivity and Sandell’s sensitivity of complex were 1.41 × 10⁴ L/mol/cm and 0.0075 μg/cm², respectively. The stoichiometry of complex was 1: 3 established from Job’s method of continuous variation, molar ratio method and logarithmic slope method. The proposed method was applied for determination of ruthenium(III) in binary and ternary, synthetic mixtures corresponding to fission product elements alloy and ruthenium(III) catalysts.     

Heterostructured Catalysts for Electrocatalytic and Photocatalytic Carbon Dioxide Reduction

Heterostructured catalysts are hybrid materials that contain interfaces between their constituents formed through combinations of multiple solid‐state materials. The presence of multiple constituents institutes a synergistic effect that endows the catalyst with superior performance and appreciable potential in a diverse range of catalytic applications, including electrocatalytic and photocatalytic reduction of carbon dioxide. These promising catalysts can support a feasible method for large‐scale processing of valuable carbonaceous feedstock or fuel generation and alleviation of atmospheric carbon dioxide levels. Such technologies will serve as the much‐needed remedy for the global energy and environmental crisis. A broad spectrum of recently developed heterostructured catalysts pertaining to electrocatalytic and photocatalytic carbon dioxide reduction is evaluated. The insights included are of relevance to refresh fundamentals pertaining to the electron transfer processes leading to carbon dioxide reduction and the mechanistic reduction pathways yielding a possible multitude of carbonaceous products. Detailed discussions provide a rational understanding of how the hybrid and resultant properties from various combinations are useful in enhancing catalytic function. Lastly, the performance profiles of various catalyst structures together with modification strategies employed are of interest to highlight the current challenges to and directions for future catalyst development.     

SFFS–SVM based prostate carcinoma diagnosis in DCE-MRI via ACM segmentation

The prostate carcinoma is amongst the most commonly occurring cancers in Taiwanese males. Moreover, it is one of the chief reasons for cancer deaths among Taiwanese men, and early diagnosis of prostate cancer is vital for effective treatment. In this work, a diagnosis model for identifying the prostate carcinoma in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is proposed. The urologists utilize the DCE-MRI as a support mechanism for better diagnosis of the carcinoma development in the prostate. Gadolinium is utilized as the contrast agent for the DCE-MRI data, and it was injected once and the time series data were captured at distinct time intervals of 0, 20, 60, and 100 s correspondingly. Primarily, after pre-processing the DCE-MRI information, the prostate data is segmented by employing the active contour model. Subsequently, 136 features are extracted from the segmented prostrate expanse of the DCE-MRI data, and the relative intensity change curve is computed. Afterward, Fisher’s discriminant ratio and sequential forward floating selection is deployed for choosing ten highly discriminative features. Lastly, the segmented prostate regions are classified into two groups, namely: tumor and normal classes by employing the support vector machine classifier. The experimental results elucidate that the proposed system is superior on the subject of accuracy, sensitivity, and specificity when compared with specific existing methods. Additionally, the proposed system also demonstrates a 94.75% accuracy. Moreover, this signifies the fact that the proposed method for analyzing the DCE data has shown prodigious prospects in the prostate carcinoma diagnosis.

     

Design-to-testing: a low-power, 1.25 GHz,single-bit single-loop continuous-time $$\Delta \Sigma$$ modulator with 15 MHz bandwidth and 60 dB dynamic range

Continuous-time Delta-Sigma (CT-\(\Delta \Sigma\)) analog-to-digital converters have been extensively investigated for their use in wireless receivers to achieve conversion bandwidths >15 MHz and higher resolution of 10–14 bits. This paper presents the complete design-to-testing tutorial of a state-of-the-art high-speed single-bit CT-\(\Delta \Sigma\) architecture and its circuit design details in 0.13 μm CMOS technology node sampling at 1.25 GS/s. The designed modulator achieves higher dynamic range of 60 dB in a wide conversion bandwidth of 15 MHz and consumes only 3.5 mW. The proposed modulator achieves a Figure of Merit of 154 fJ/level.     

Microwave-assisted asymmetric ring opening of meso-epoxides with aromatic amines catalyzed by a Ti-S-(−)-BINOL complex

Catalytic asymmetric ring opening of cyclohexene oxide and meso-stilbene oxide with anilines was catalyzed by a Ti-(S)-(−)-BINOL complex to afford β-amino alcohols in high yield (up to 95%) and good enantioselectivities (ee up to 55%) under microwave irradiation. The reaction using a microwave was found to be 10 times faster than traditional oil-bath heating with retention of enantioselectivity.     

Convenient synthesis of 5-methylene-4-substituted-2(5H)-furanones

A synthesis of novel 4-(substituted)benzyl-5-methylene-2(5H)-furanones involving Stobbe condensation of substituted aldehydes with ethyl levulinate followed by treatment with acetic anhydride in the presence of sodium acetate, has been developed.     

SH3-like fold proteins are structurally conserved and functionally divergent

The folding space for all the protein sequences is limited. Therefore it was observed that many proteins, whose sequences are not related, have similar fold characteristics. The fold databases like SCOP and CATH have classified various protein folds. However, in-depth analysis of the functional features of these folds was not done. We analyzed about twenty unique SH3-like folded proteins in their structural environment and functional characteristics. From our analysis it is apparent that the SH3-like folds could carry out various functions by modulation of loops and the functional region is restricted to one side of a particular sheet helped by two or three loops. The functions vary from oligonucleotide-binding to peptide-binding and other ligand binding. Although certain degree of sequence similarity was observed among the SH3-fold proteins, the similarity was restricted to the beta-strand regions of the proteins.     

Network Health Monitoring of WSNs Using Node Loss Rate Calculations

Wireless Personal Communications - The inherent stringent energy and bandwidth constraints complicate the ascertainment of the reasons for the failure in wireless sensor networks (WSNs). This work...     

Modular forms and ellipsoidal T-designs

The Ramanujan Journal - In recent work, Miezaki introduced the notion of a spherical T-design in $$\mathbb {R}^2$$ , where T is a potentially infinite set. As an example, he offered the $$\mathbb...