Mechanisms of Drying of Skin-Forming Materials. II.Droplets of Heat Sensitive Materials

ABSTRACT

Drying studies were carried out on single droplets of gelatin solution, typifying a skin forming, heat-sensitive material. Each droplet was suspended from a novel rotating glass nozzle which enabled direct measurement of its weight and temperature during drying. Observations using this appartatus successfully detected the decrease in core temperature and increase in drying rate resulting from granule dissolution at 30 °C.

The study covered air temperatures in the range 19 °C–175 °C. Scanning Electron Microscopy was used to examine the dried crusts. The resistance of the skin to vapour diffusion was significantly increased with an increase in the air temperature. At air temperature > 60 °C the dried particle lost the structure and properties of the original powder. The optimum drying conditions to avoid this were predicted for this type of skin forming-material.     

The Housing and Location Preferences of Adelaide Residents

There has been a growing mismatch between household and housing types in Australian cities in recent years. At the same time housing has become increasingly expensive, while low-density urban development has meant increasing social and economic costs for households in fringe suburbs. This paper explores current housing and location preferences of Adelaide residents. The findings suggest that home ownership and the single-storey detached dwelling are well entrenched preferences among residents, and that as yet, the personal costs of the linear spread of the city have not impacted significantly on housing and location preferences.     

Unit Commitment solution using an optimized genetic system

This paper presents an investigation into the application of an optimized Genetic Algorithm (GA) to solve the Thermal Unit Commitment (UC) problem. A Parallel structure was first developed to handle the infeasibility problem in a structured and improved GA which provides an effective search process and therefore greater economy. The proposed methodology resulted in a better performance with faster operation by using both computational methods and classification of unit characteristics. Typical constraints such as system power balance, minimum up and down times, start-up and shut-down ramps, have also been considered. A number of important parameters (standard and new parameters) of the UC problem have been identified. The proposed method is implemented and tested using a C# program. The tests are carried out using two systems including 10 and 20 units during a scheduling period of 24 h. The results are finally compared with those obtained from genetic schemes in other similar investigations through which the effectiveness of the proposed scheme is affirmed.     

Compact modeling of CMOS transistors under variable uniaxial stress

This paper presents a novel implementation of variable uniaxial mechanical stress model to be used with DC circuit simulation, e.g. using BSIM3v3 transistor model. Based on transistor measurements under various uniaxial stress conditions two stress-dependent parameters are identified, namely the carriers mobility and to a lesser extend the carrier saturation velocity. The effect of the parasitic source/drain resistance on the piezoresistive coefficient determination is addressed in detail. Using the fundamental piezoresistive coefficients, the model has implemented a general relation to calculate the coefficients for arbitrary directions of current and stress in the (0 0 1) silicon (Si) plane. The extended transistor model allows for simulating the effect of uniaxial stress on any MOSFET geometry, under different operation conditions and for any combination of the drain current and stress orientations in the (0 0 1) silicon (Si) plane. The method proposed in this paper is validated by static and dynamic stress-dependent simulations and comparison with experimental data. The method is simulator-independent and can be adapted to other bulk CMOS technologies including SOI processes.     

Multi-metric geographic routing for vehicular ad hoc networks

Wireless Networks - Maintaining durable connectivity during data forwarding in Vehicular Ad hoc Networks has witnessed significant attention in the past few decades with the aim of supporting most...     

On the distribution of the product and ratio of products of EGK variates with applications

Video streaming over peer-to-peer (P2P) networks is a promising approach for scalable IPTV and online games. Distributing high-quality videos among users who employ numerous channels in multi-channel P2P live streaming systems, however, still suffers from many challenges arisen from the network size and dynamicity, channel resource imbalance, and bandwidth limitations. Other challenges also exist, including instability of peers, the peers’ low participation, large startup and playback delays, low quality of received video, and resource insufficiency in unpopular channels. In this paper, ReDePoly, with some levels of distributed intelligence, is proposed to reduce the bootstrapping delay and to increase the service quality. The key idea is to substitute agents with bootstrapping peers in the channels to model user behaviors and to share the aggregated knowledge among the agents to disseminate the learned models. Accordingly, the agents dynamically predict the behavior of participating peers to pre-assign them to the predicted channels and to parallelize the threads related to viewing behavior and channel switching. In case of congested channels, the new agents are distilled to mitigate the agent responsibilities. Simulation results show that the proposed approach outperforms the other existing methods regarding the channel switching delay, recovery delay, and quality of service.     

Fluidization Behavior of Cohesive Ca(OH)2 Powders Mixed with Hydrophobic Silica Nanoparticles

Dry mixing with hydrophobic silica nanopowders was used to improve the fluidization quality of Ca(OH)₂ particles which belong to the Geldart C group and, thus, normally cannot be fluidized. Three parameters, i.e., sieved size of Ca(OH)₂ particles and sieved size and weight percentage of SiO₂ nanoparticles were selected for experiments. A direct proportionality was found between the coverage quality of materials over each other and the fluidization behavior of their corresponding adsorbents. Optimum SiO₂ size and concentration values were determined for the improvement of Ca(OH)₂ fluidizability. The sieved size of Ca(OH)₂ powder had no consequential effect on the coverage quality. The Richarson‐Zaki equation and fractal analysis combined with a modified Richardson‐Zaki approach were proposed for prediction of the fluidization quality and agglomerate size.     

An Improved Non‐CSD 2‐Bit Recursive Common Subexpression Elimination Method to Implement FIR Filter

The number of adders and critical paths in a multiplier block of a multiple constant multiplication based implementation of a finite impulse response (FIR) filter can be minimized through common subexpression elimination (CSE) techniques. A two‐bit common subexpression (CS) can be located recursively in a non‐canonic sign digit (CSD) representation of the filter coefficients. An efficient algorithm is presented in this paper to improve the elimination of a CS from the multiplier block of an FIR filter so that it can be realized with fewer adders and low logical depth as compared to the existing CSE methods in the literature. Vinod and others claimed the highest reduction in the number of logical operators (LOs) without increasing the logic depth (LD) requirement. Using the design examples given by Vinod and others, we compare the average reduction in LOs and LDs achieved by our algorithm. Our algorithm shows average LO improvements of 30.8%, 5.5%, and 22.5% with a comparative LD requirement over that of Vinod and others for three design examples. Improvement increases as the filter order increases, and for the highest filter order and lowest coefficient width, the LO improvements are 70.3%, 75.3%, and 72.2% for the three design examples.     

Empirical expression for base transit time in bipolar transistors

A new and compact formula for the base transit time, τ _b , of a modern high speed npn bipolar transistor with exponential base doping profile is derived considering doping dependence of mobility, bandgap narrowing effect, high injection effect and carrier velocity saturation at the base edge of the collector–base junction. The collector current density, J _c , and minority carrier stored charge, Q _b , in the base are separately expressed as a function of the injected electron density n _o in the base in order to find an empirical expression for τ _b . The modelling of J _c , Q _b and τ _b is essential for the design of high-speed bipolar transistor. The expressions are applicable for arbitrary injection before the onset of the Kirk effect and they are simple and straight forward to give insight into device operation. The base transit time calculated analytically is compared with simulation results in order to demonstrate the validity of the assumptions made in deriving the expression. The closed form expressions for collector current density and base transit time offer a physical insight into device operation and are a useful tool in device design and optimization.