Hot-carrier degradation of submicrometer p-MOSFETs withthermal/LPCVD composite oxide

It is shown that while gate oxides containing thermal/LPCVD composite oxide have lower defect densities than gates using only thermal oxides, they are more susceptible to hot-carrier degradation. The hot-carrier-induced degradation of composite oxides is worse in p-channel MOSFETs than in n-channel MOSFETs. This sensitivity of p-channel MOSFETs is caused by higher electron trapping levels in LPCVD oxides. For 150-Å gate technology, the hot-carrier-degradation resistance of thermal/LPCVD composite gate oxides with a 70-Å or thicker thermal oxide layer approaches that of high-quality pure thermal oxide     

Process Intensification and Integration: an assessment

A considerable number of studies have been performed for improving the efficiency of production processes, of energy supply and utilisation, while reducing emissions of greenhouse gases, volatile organic compounds and other pollutants. This has been a very important task which this journal has been targeting. As a response to these industrial and societal requirements considerable research effort has been targeted to process integration and process intensification. This article has made an attempt for a short assessment of those advanced engineering approaches.     

Synthesis of regional networks for the supply of energy and bioproducts

This article presents a method for the synthesis of regional renewable energy supply chains, based on Mixed-Integer Linear Programming (MILP). This method addresses the challenges presented by biomass resources. The main challenges are the distributive and varied availabilities regarding both location and time. This work also aims to maximise the economically viable utilisation of resources, accounting for the competition between energy and food production. A four-layer supply chain superstructure has been developed, which includes the harvesting, preparation, core processing and distribution of products. This considered system’s boundaries involve a region, which is then divided into zones for optimising conversion operations and transportation flows. An MILP model has been formulated with profit maximisation as the optimisation criterion. The environmental impact is evaluated by the carbon footprint. The sensitivity of the optimal solutions is analysed for different regions’ sizes, transportation costs, pre-processing alternatives and the co-production of food and energy.     

Analysis and integration of fuel cell combined cycles for development of low-carbon energy technologies

Integrated and combined cycles (ICC, CC) traditionally involve gas and steam turbines only. The paper analyses the further integration of high-temperature fuel cells (FC) having high electrical efficiency reaching up to 60% compared with 30–35% for most gas turbines. The previous research on FC hybrids indicates achieving high efficiencies and economic viability is possible. The ICC of various FC types—their performance and the potential for utilisation of renewables—are analysed considering also power generation capacity and site heat integration context. Further research and development with industrial relevance are outlined focusing on CO₂ emissions reduction.     

Contributing to sustainability: addressing the core problems

Clean Technologies and Environmental Policy -     

Bismuth oxide-related photocatalysts in green nanotechnology: A critical analysis

A survey addressing the uses of bismuth oxide in photocatalysis is presented. The richness of literature on such a specific topic proves the growing importance of this compound as a valid tool in pollution abatement and environmental decontamination. Many research groups have focused their activity on how to improve the photocatalytic properties of this semiconductor and several solutions have been adopted in the synthesis method, often based on wet-chemical processes. The impressive development of nanoscience helped in understanding and identifying process variables and operative conditions aiming at optimizing the yield of this promising photocatalytic material in the utilization of solar energy.     

Recent developments in Process Integration

Process Integration supporting process design, integration and optimisation has been around for more than 40 years. Its development has been closely related to developing the Chemical Engineering, implementation of mathematical modelling and the application of information technology. Its development has been accelerating as the methodology has been able to provide answers and support for important issues regarding economic development—energy, water and resources better utilisation and savings. This contribution is targeted towards a short overview of recent achievements and future challenges.     

A Bayesian approach to sequential monitoring of nonlinear profiles using wavelets

We consider change‐point detection and estimation in sequences of functional observations. This setting often arises when the quality of a process is characterized by such observations, called profiles, and monitoring profiles for changes in structure can be used to ensure the stability of the process over time. While interest in phase II profile monitoring has grown, few methods approach the problem from a Bayesian perspective. We propose a wavelet‐based Bayesian methodology that bases inference on the posterior distribution of the change point without placing restrictive assumptions on the form of profiles. By obtaining an analytic form of this posterior distribution, we allow the proposed method to run online without using Markov chain Monte Carlo (MCMC) approximation. Wavelets, an effective tool for estimating nonlinear signals from noise‐contaminated observations, enable us to flexibly distinguish between sustained changes in profiles and the inherent variability of the process. We analyze observed profiles in the wavelet domain and consider two possible prior distributions for coefficients corresponding to the unknown change in the sequence. These priors, previously applied in the nonparametric regression setting, yield tuning‐free choices of hyperparameters. We present additional considerations for controlling computational complexity over time and their effects on performance. The proposed method significantly outperforms a relevant frequentist competitor on simulated data.