Designing sustainable alternatives for batch operations using an intelligent simulation–optimization framework

The drive towards sustainability has compelled the batch process industries to implement the concept of environmentally friendly plants. However, the temporal nature of processing in these processes obviates the application of traditional waste minimization, material recycling, or energy integration schemes. Further, most of the existing methodologies for generating sustainable alternatives are restricted to specific problems, such as reaction byproduct, wastewater, or solvent minimization. In this paper, we propose an intelligent simulation–optimization framework for identifying comprehensive sustainable alternatives for batch processes. We differentiate between wastes generated by the reaction–separation process and cleaning wastes. A P-graph-based approach is used for identifying the root cause of process waste generation and generating broad design alternatives. Specific variable-level design solutions are then identified and evaluated using process simulation. The cleaning wastes resulting from the optimized process are also minimized using a source-sink allocation method that allows design of recycle network structure. A multi-objective stochastic optimization method is used to integrate the analysis so that the overall process economic and environmental footprint is optimized. We illustrate the proposed methodology using a well-known literature case study involving reaction, distillation and washing operation.     

PCS mobility support over fixed ATM networks

As broadband multimedia services and wireless services become popular, there is growing interest in the industry to support ATM over a wireless link, and wireless access to fixed ATM networks. We focus on the internetworking of PCS and ATM networks, in which the air interface remains one of the PCS standards and the backbone is an ATM network with mobility support. It is desirable to minimize the impact of the internetworking and mobility support on the existing/emerging PCS and ATM specifications. A network architecture, a protocol reference model, and signaling protocols for PCS mobility support over fixed ATM networks are described. They are compared against other implementation alternatives and the trade-offs are discussed. Some performance results of the proposed architecture are also presented     

Background learning for robust face recognition with PCA in the presence of clutter.

We propose a new method within the framework of principal component analysis (PCA) to robustly recognize faces in the presence of clutter. The traditional eigenface recognition (EFR) method, which is based on PCA, works quite well when the input test patterns are faces. However, when confronted with the more general task of recognizing faces appearing against a background, the performance of the EFR method can be quite poor. It may miss faces completely or may wrongly associate many of the background image patterns to faces in the training set. In order to improve performance in the presence of background, we argue in favor of learning the distribution of background patterns and show how this can be done for a given test image. An eigenbackground space is constructed corresponding to the given test image and this space in conjunction with the eigenface space is used to impart robustness. A suitable classifier is derived to distinguish nonface patterns from faces. When tested on images depicting face recognition in real situations against cluttered background, the performance of the proposed method is quite good with fewer false alarms.     

A predictor-corrector guidance control scheme for AGV navigation

This paper presents a scheme that employs feedforward control in conjunction with a predictor-corrector scheme for guidance control of Automated Guided Vehicles (AGVs). The predictor-corrector scheme provides the desired values of steering parameters which depend on the geometry of the track and a driving criterion. The geometry of the track/road ahead of the vehicle is obtained by extrapolating the identified (estimated) geometry of the track/road traversed during the elapsed time interval. This real-time identification is carried out by fitting a curve to the path traversed by the vehicle. The coordinates of the path are provided by a transformation formulation which makes use of the motion parameters and a kinematic model of the vehicle. The driving criterion specifies the positioning of the AGV on the track. Several possible criteria are identified in the paper and mathematical formulations are presented for one such criterion. Results of off-line calculations using simulated track profiles and experimental data obtained using a prototype AGV while following various track profiles are provided for illustration.     

Reduced chemically modified graphene oxide for supercapacitor electrode

An efficient active material for supercapacitor electrodes is prepared by reacting potassium hydroxide (KOH) with graphene oxide followed by chemical reduction with hydrazine. The electrochemical performance of KOH treated graphene oxide reduced for 24 h (reduced chemically modified graphene oxide, RCMGO-24) exhibits a specific capacitance of 253 F g^-1 at 0.2 A g^-1 in 2 M H₂SO₄ compared to a value of 141 F g^-1 for graphene oxide reduced for 24 h (RGO-24), and good cyclic stability up to 3,000 cycles. Interestingly, RCMGO-24 demonstrated a higher specific capacitance and excellent cycle stability due to its residual oxygen functional groups that accelerate the faradaic reactions and aid in faster wetting. This non-annealed strategy offers the potential for simple and cost-effective preparation of an active material for a supercapacitor electrode.     

Significance of Aluminum on Hardness of Titanium Aluminum Nitride Deposited by Magnetron Co-Sputtering

Ti_{1− x} Al _x N films were synthesized by reactive magnetron co-sputtering with different aluminum compositions. X-ray diffraction, secondary ion mass spectrometry, nanoindentation, and atomic force microscopy (AFM) techniques were used to analyze these films. The as-deposited films were crystalline for concentrations of Al (35%, 40%, 55%, and 64%) and at 81% it became amorphous. Nanoindentation hardness increases with aluminum and started to decrease beyond 81% of aluminum. Continuous multicycle indentation technique is used to analyze the failure mode of the film with highest hardness. AFM topography analysis of this film exhibited edge cracks outside and inside the indentation area and sink-in when the penetration reaches the substrate.     

Topic Distillation and Spectral Filtering

This paper discuss topic distillation, an information retrieval problemthat is emerging as a critical task for the www. Algorithms for this problemmust distill a small number of high-quality documents addressing a broadtopic from a large set of candidates.We give a review of the literature, and compare the problem with relatedtasks such as classification, clustering, and indexing. We then describe ageneral approach to topic distillation with applications to searching andpartitioning, based on the algebraic properties of matrices derived fromparticular documents within the corpus. Our method – which we call special filtering – combines the use of terms, hyperlinks and anchor-textto improve retrieval performance. We give results for broad-topic querieson the www, and also give some anecdotal results applying the sametechniques to US Supreme Court law cases, US patents, and a set of WallStreet Journal newspaper articles.     

Microstructural analysis of sintering behavior of intra-grain pores

A latticebased Monte Carlo simulation approach has been developed for studying the behavior of intragrain pores during the intermediate and final stages of sintering. The changes of the microstructures and the resulting properties of intragrain pores during sintering are easily examined. The sintering behavior such as pore size distribution, average pore size, etc. is in very good agreement with the experimental observations. In addition, the relationships between the number of pores and the average pore volume agree well with theory.     

Simultaneous effects of adhesion and poly-dispersity on microstructures and geometrical properties in particle deposition

The simultaneous effects of adhesion and polydispersity on packing (or deposit) microstructures and their bulk properties are examined. The results show that the microstructures and bulk properties of the deposits vary sharply with the introduction of even small adhesion and polydispersity. A structural phase diagram is obtained as functions of adhesion and polydispersity. Increases in adhesion lead to noticeable or large fluctuations in packing fractions for polydisperse systems. However, the packing fraction can be stabilized and the fluctuations greatly reduced regardless of the magnitude of the polydispersity index by keeping the adhesion relatively low (i.e., s≤0.1).     

Electronic and structural properties of alkaline-earth oxides under high pressure

A pilot study was conducted to measure the interocclusal distance in patients with class I, II and III skeletal patterns. Ten patients were randomly selected for each skeletal pattern group. The measurements of interocclusal distance were obtained from lateral cephalometric radiographs of each patient. The results indicated that there was a significant difference (p < 0.05) between the interocclusal space of skeletal class II and class III patients.