Steam assisted biomass gasification—an overview

Biomass gasification technologies have matured over the years. In the past decade, numerous types of gasifiers have been developed and tested. This article reviews the status of steam assisted biomass gasifiers. It first discusses the challenges and the key operating parameters for steam‐biomass gasification and their effects on the gasifier performance. The article then summarises the progress and status of commercial or demonstration scale steam assisted biomass gasifiers available in the world.     

Cd(Zn,S)Se quaternary thin films for electrochemical photovoltaic cell application

In this study, Cd_1−xZn_xS_ySe_1−y (0 ≤ x = y ≤ 0.35) photoelectrodes are deposited via inexpensive facile chemical bath deposition. The effects of Zn and S doping on the compositional, microstructural, electrical, and optical properties of thin films were analysed. The electrochemical photovoltaic (EPV) cell of configuration Cd_1−xZn_xS_ySe_1−y/0.25M sulfide/polysulfide/C was assembled to examine the different performance parameters in light and in dark conditions. An EPV cell fabricated with the Cd_1−xZn_xS_ySe_1−y (0 ≤ x = y ≤ 0.075) photoelectrode exhibited a maximum photoconversion efficiency of 3.18%. This performance can be attributed primarily to the enhanced light-absorption ability of the material because of the enhanced rough microstructure and low recombination of photo-injected electrons with the electrolyte. The photovoltaic (PV) performance is significantly enhanced after doping CdSe with Zn and S.     

Impact of parametric variation on combustion characteristics of hydrogen-fueled strut based scramjet combustor at supersonic speed

Supersonic combustion ramjet engine is more fascinating among all the air-breathing engines. Due to its higher thrust to weight ratio, researchers are more interested to get the superior combustion performance at the optimum boundary conditions. The flow field characteristics and combustion performance have been analysed with the help of Ansys 14.0 software. Generic scramjet combustor of German Aerospace Center (DLR) has been taken into consideration for comparison purpose and off design analysis has been conducted to investigate and analyse the changes. Two dimensional compressible Reynolds Averaged Navier-Stokes (RANS) turbulence model has been opted with the finite-rate/eddy-dissipation reaction model. K-ε two equation turbulence model has been selected to reach up to reasonable accuracy. Validation of the present work has been done with the help of both non-reacting and reacting type data from open literature. To choose the appropriate meshing of the computational model three different types of mesh elements, that is, coarse, medium and fine has been analysed and also grid independence analysis is performed. The present article objective is to get optimum boundary condition by changing the incoming air temperature and pressure at constant Mach number to connect the bridge between incoming air temperature and pressure to the change in velocity throughout the combustion chamber. The detailed understanding and explanation have been done by varying the temperature range of incoming air because of its major impact on combustion performance. Nonetheless, a small variation of air pressure will also discuss to observe the parameters which majorly influence while doing performance analysis. At the end the Optimum boundary condition for the present computation work is observed to be at 833 K temperature with 115 299 Pa pressure.     

Analysis of Underlap Strained Silicon on Insulator MOSFET for Accurate and Compact Modeling

Silicon - Recently, transistors with an underlapped gate structure have been widely studied to overcome several challenges associated with nanoscale devices. In this work, underlap region is...     

Sensitivity Analysis of Junction Free Electrostatically Doped Tunnel-FET Based Biosensor

Silicon - The electrostatic doping technique has a remarkable ability to reduce random dopant fluctuations (RDFs), fabrication complexity and high thermal budget requirement in the fabrication...     

Implementation of Band Gap and Gate Oxide Engineering to Improve the Electrical Performance of SiGe/InAs Charged Plasma-Based Junctionless-TFET

Silicon - This paper reports on a charged plasma-based adjustable bandgap source/channel (So/Ch) interface using a new semiconductor compound (SiGe/ InAs) and bimaterial oxide (HfO2/SiO2)...     

Predicting chemical reaction outcomes: A grammar ontology-based transformer framework

Discovering and designing novel materials is a challenging problem as it often requires searching through a combinatorially large space of potential candidates, typically requiring great amounts of effort, time, expertise, and money. The ability to predict reaction outcomes without performing extensive experiments is, therefore, important. Toward that goal, we report an approach that uses context-free grammar-based representations of molecules in a neural machine translation framework. This involves discovering the transformations from the source sequence (comprising the reactants and agents) to the target sequence (comprising the major product) in the reaction. The grammar ontology-based representation hierarchically incorporates rich molecular-structure information, ensures syntactic validity of predictions, and overcomes over-parameterization in complex machine learning architectures. We achieve an accuracy of 80.1% (86.3% top-2 accuracy) and 99% syntactic validity of predictions on a standard reaction dataset. Moreover, our model is characterized by only a fraction of the number of training parameters used in other similar works in this area.     

Effects of Hydrogen-Dilution on Opto-Structural Properties of Hot-wire CVD Grown a-Si:H/nc-Si:H Multilayer for Photovoltaics

The multilayered thin film structure of amorphous silicon (a-Si:H) and nanocrystalline silicon (nc-Si:H) provides the possibility of bandgap tuning for fabrication of multijunction solar cells. This paper communicates a detailed analysis of optical and structural properties of a-Si:H/nc-Si:H multilayer thin films by hot-wire chemical vapor deposition at low hydrogen (H₂) and silane (SiH₄) flow rates. A set of multilayer films with 25 bilayers of a-Si:H/nc-Si:H are prepared using different hydrogen-dilution of SiH₄ in the alternating nc-Si:H layers. The first and the second order Raman scattering studies reveal the presence of mixed phases of silicon in the nc-Si:H layers. Raman and XRD investigation of the films confirm the presence of different sizes of the silicon nanocrystals. The optical spectroscopic analysis instead of FTIR analysis of multilayer films is utilized uniquely to determine the hydrogen content in the a-Si:H/nc-Si:H multilayers and is related to the amorphous phase of the films. No significant change in hydrogen content is observed and the amorphous phase is found to decrease with increase in hydrogen dilution. Further, no quantum size effect (QSE) was observed due to the large growth time of nc-Si:H layers. Thus the experimental result shows that the bandgap of multilayer films decreases due to reduction in amorphous silicon phase, ineffective QSE and relative loss of hydrogen content.

     

E3 Ubiquitin Ligase APC/CCdh1 Regulation of Phenylalanine Hydroxylase Stability and Function

Phenylketonuria (PKU) is an autosomal recessive metabolic disorder caused by the dysfunction of the enzyme phenylalanine hydroxylase (PAH). Alterations in the level of PAH leads to the toxic accumulation of phenylalanine in the blood and brain. Protein degradation mediated by ubiquitination is a principal cellular process for maintaining protein homeostasis. Therefore, it is important to identify the E3 ligases responsible for PAH turnover and proteostasis. Here, we report that anaphase-promoting complex/cyclosome-Cdh1 (APC/C)^Cdh1 is an E3 ubiquitin ligase complex that interacts and promotes the polyubiquitination of PAH through the 26S proteasomal pathway. Cdh1 destabilizes and declines the half-life of PAH. In contrast, the CRISPR/Cas9-mediated knockout of Cdh1 stabilizes PAH expression and enhances phenylalanine metabolism. Additionally, our current study demonstrates the clinical relevance of PAH and Cdh1 correlation in hepatocellular carcinoma (HCC). Overall, we show that PAH is a prognostic marker for HCC and Cdh1 could be a potential therapeutic target to regulate PAH-mediated physiological and metabolic disorders.