Development and application of organic phase change mixtures in thermal storage gypsum wallboard

A latent heat storage material which would be useful in hot climate is proposed. It is a mixture of 93–95 wt% commercial Methyl Palmitate (MeP) with 7-5 wt% commercial Methyl Stearate (MeS), having a melting-freezing interval of approximately 23–26.5°C and a latent heat of transition of at least 180 kJ/kg.Normal wallboard may be impregnated with up to 25 wt% of one of these mixtures. Air passing over such an impregnated wallboard would be cooled down due to the heat absorption taking place between 23–26.5°C when the mixture melts. Recharging the wallboard will occur at 22–23°C during freezing, when the latent stored heat is released to the cool night air.The total storage capacity of such an impregnated wallboard, in a 3.5°C temperature interval, is at least twelve times higher than the storage capacity of wallboard alone over this range.     

Functional near-infrared spectroscopy.

The purpose of the this article is to describe an emerging neuroimaging technology, functional near-infrared spectroscopy (fNIRs), which has several attributes that make it possible to conduct neuroimaging studies of the cortex in clinical offices and under more realistic, ecologically valid parameters. fNIRs use near-infrared light to measure changes in the concentration of oxygenated and deoxygenated hemoglobin in the cortex. Although fNIR imaging is limited to the outer cortex, it provides neuroimaging that is safe, portable, and very affordable relative to other neuroimaging technologies. It is also relatively robust to movement artifacts and can readily be integrated with other technologies such as EEG.     

Synthesis and properties of starch-graft-acrylic acid/Na-montmorillonite superabsorbent nanocomposite hydrogels

The graft copolymerization of acrylic acid (AA) onto starch was carried out with monomer/starch weight ratio = 1.5. Cerium ammonium nitrate (CAN) and N,N′-methylenebis acrylamide (NMBA) were used as initiator and crosslink agent, respectively. Na-montmorillonite was used as nanoparticles. Starch-graft-acrylic acid/Na-MMT (S-g-AA/MMT) nanocomposite hydrogels were characterized by X-ray diffraction (XRD) and FTIR analysis. The effect of Na-MMT content in nanocomposite hydrogels on the swelling behavior was investigated. Increasing the Na-MMT/monomers ratio up to 1% causes an increment in water absorbency, which indicates that Na-MMT can improve the ability of water absorbency but further increase of Na-MMT causes a decrease in water absorbency. In addition, we describe the removal of safranine T from aqueous solutions using S-g-AA/MMT nanocomposite hydrogels. Effects of various parameters such as treatment time, initial dye concentration, and amount of the Na-MMT were investigated. The Freundlich equations were used to fit the equilibrium isotherms. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ferroelectric studies and impedance analysis of PLZT (10/52/48) electroceramics

Perovskite Pb_0.90La_0.10(Zr_0.52Ti_0.48)O₃ ceramic material was prepared through sol–gel process. Structural, phase formation and thermal properties were confirmed by X-ray diffraction, thermogravimetry and differential thermal analysis; size and microstructural study was carried out using particle size analyser and scanning electron microscope. The electrical properties of the ceramics were investigated as a function of both temperature (from room temperature to 500 °C) and frequency (from 100 Hz to 1 MHz) using complex impedance spectroscopy (CIS). The impedance spectrum results indicate the decrease in dielectric constant with increase in frequency while the dielectric loss increases with frequency. The activation energy of the sample was calculated from the slope of the Arrhenius plot as 0.129 eV from the Arrhenius’s plot of dc conductivity versus inverse of absolute temperature. The dc conductivity was obtained from CIS measurements and the activation energy. The remnant polarization (P_r) and coercive electric fields (E_c) are found out as 6.52 μC/cm² and 2.55 kV/cm from the ferroelectric loop measured at room temperature.     

Performance evaluation of AVS/RS under various design scenarios: a case study

In this study, performance evaluation of an autonomous vehicle storage and retrieval system (AVS/RS) is completed under various pre-defined design scenarios. Design scenarios are considered based on the rack configuration of the warehouse, namely the number of aisles, bays, and tiers, number of autonomous vehicles (AVs), and number of lifts. The system is simulated using ARENA 12—a commercial software. Seven performance measures are observed from the simulation results. These are: the average cycle time, average utilization of the AVs, average utilization of the lifts, average waiting time in the AVs’ queue, average waiting time in the lifts’ queue, average number of transactions waiting in the AVs’ queue, and average number of transactions waiting in the lifts’ queue. Total cost of the system is also integrated into the analysis. The results are analyzed via graphs. Various design options and their costs facilitate the evaluation of the best design for the warehouse manager. The case study is completed for a company that utilizes AVS/RS in France.     

Adaptive dimensional control based on in-cycle geometry monitoring and programming for CNC turning center

This paper presents a method to compensate the dimensional deviation, irrespective of the sources for its components, and to integrate the dimensional verification and dimensional control processes. Nowadays, approach in compensation of dimensional deviation is based on decomposing the deviation. The decomposing criterion is the error source such as positioning errors, thermal deformation, mechanical loads, tool wear, kinematical errors, dynamic force, and motion control. Then, one or even more components are modeled and compensated. On contrary, the proposed method is based on the decomposing of the tool path and consideration of the batch samples. The decomposition criteria ignores the error sources as: (1) speed of variation in space of the total deviation value for the tool path decomposition and (2) the speed of variation in time of the deviation model parameters values for batch samples decomposition. The data from the geometry holistic monitoring are used for both modeling and compensation of systematic component of the total error, also for checking the compliance with technical requirements. Two algorithms for processing of the data provided by geometry monitoring, namely the adaptive?Cpredictive algorithm and adaptive?Coptimal algorithm, are presented. Nine experimental batches were machined to verify the efficiency of the proposed method using various model structures and processing algorithms. The results of method application have shown a reduction of deterministic and even nondeterministic part of the total error in what concern accuracy and precision. For the entire batch, the level of remanent error is less than 5% for deterministic part, and less than 75% for nondeterministic part. These results are clearly better than the other results reported; moreover, they refer to the whole processing error and entire batch.     

Knowledge-based artificial neural network model to predict the properties of alpha+ beta titanium alloys

In view of emerging applications of alpha+beta titanium alloys in aerospace and defense, we have aimed to develop a Back propagation neural network (BPNN) model capable of predicting the properties of these alloys as functions of alloy composition and/or thermomechanical processing parameters. The optimized BPNN model architecture was based on the sigmoid transfer function and has one hidden layer with ten nodes. The BPNN model showed excellent predictability of five properties: Tensile strength (r: 0.96), yield strength (r: 0.93), beta transus (r: 0.96), specific heat capacity (r: 1.00) and density (r: 0.99). The developed BPNN model was in agreement with the experimental data in demonstrating the individual effects of alloying elements in modulating the above properties. This model can serve as the platform for the design and development of new alpha+beta titanium alloys in order to attain desired strength, density and specific heat capacity.

     

Studies concerning the use of <Emphasis Type="Italic">Lactobacillus helveticus</Emphasis> and <Emphasis Type="Italic">Kluyveromyces marxianus</Emphasis> for rye sourdough fermentation

The aim of this study was to investigate the fermentation behaviour, antioxidant activity and rheological behaviour of the sourdoughs prepared with Lactobacillus helveticus and Kluyveromyces marxianus. The final acidity of the sourdough after 18 h of fermentation was higher at higher temperatures (40 °C) and for the formulations with whole rye flour. The highest lactic/acetic acid ratios were obtained in case of more fluid sourdoughs fermented at 40 °C. The antioxidant properties of the sourdoughs are correlated with metabolic activity of the microorganisms, the DPPH radical scavenging activity being higher for optimum conditions of Lactobacillus helveticus growth. On the other hand, the rheological properties of the sourdoughs are not significantly influenced by the temperature. Sourdoughs formulations with whole flour are more viscous, as well as the controls fermented by the spontaneous microflora. The results of the bread-making process simulation by means of Mixolab indicate differences between dough formulations mainly depending on flour type.     

Fault Tolerant Control of CSTR with ANFIS Based Dedicated Observer and State Feedback Control using Linear Quadratic Regulator under Abrupt Sensor Failure Conditions

Abstract

In this paper, Fault Tolerant Control (FTC) is attempted using an Adaptive Neuro Fuzzy Inference System (ANFIS) based dedicated observer and a Linear Quadratic Regulator (LQR) based state feedback control under abrupt sensor failure, is proposed. A Continuous Stirred Tank Reactor (CSTR) is a highly nonlinear process, exhibiting stable and unstable steady state at different regions. Fault Detection and Isolation (FDI) of such a complicated CSTR process is a mind boggling problem. In this paper, an ANFIS based dedicated observer scheme is dealt along with a statistical method of detection of the fault. Also, LQR based state feedback control is used for the closed loop servo and regulatory control. The result shows the feasibility of using the proposed method for the fault tolerant control of CSTR under abrupt sensor failure conditions.     

Specially orthotropic panel flutter control using PID controller

Controlling the flutter speed of a specially orthotropic plate of rectangular cross-section through which an inviscid compressible fluid flows is considered. A state-space model of the coupled aeroelastic system helps us to determine flutter boundaries and provides a method for applying modern control theory to the problem. So in the present study, flow is modelled by piston theory and the coupled state-space model of panel motion and flow is solved. After that, the coupled system is controlled with Proportional-Integral-Derivative controller. This makes it possible to compute the flutter dynamic pressure and so the flutter velocity at which unstable plate oscillations occur as a function of the gain coefficient. It is found that by changing the gain coefficient the flutter of the plate can indeed be pushed to higher velocities.