CALENDER

Tsunami run-up heights (R) were predicted by using two different artificial neural network (ANN) methods such as feed forward back propagation (FFBP) and generalised regression neural networks (GRNN). The R records resulting from the ground motions, which occurred between 1900 and 2007, were used during the applications. These records were gathered from three coastal states of the USA, namely California (CA), Oregon (OR) and Washington (WA). First, the earthquake moment magnitude (M _w ), the distance from the earthquake source to the run-up location (D), the latitude of the run-up location (L _x ) and the longitude of the run-up location (L _y ) were used as inputs of each ANN method. In order to evaluate the effects of the L _x and L _y on the R prediction, a second input combination consisting of the M _w and D was used. Each ANN method structured for each input combination was applied to estimate the R of both the separate state and the Western Seaboard. In general, the forecasting performance of the FFBP model that used the M _w , D, L _x and L _y in the input layer was found superior to the other models under the conditions of the used data and model structures.     

Survival of Helicobacter pylori in Turkish fermented sucuk and heat-treated sucuk during production

The aim of this study was to investigate the survival of Helicobacter pylori during production of sucuk (Turkish fermented sausage). The sucuk mixture was inoculated with H. pylori ATCC 43504 to produce a final level in the mixture of ～5 × 10(6) CFU/g. Samples in group I were fermented and dried traditionally at 22°C for 7 days. Samples in groups II and III were subjected to the traditional fermentation at 22°C for 3 days. After fermentation, group II samples were fermented and dried at 35°C for 4 days and group III samples were treated with heat until the core temperature reached 65°C. On the first day of fermentation, a 1-log reduction in H. pylori was found in all groups. The H. pylori levels in all groups increased by about 1 log CFU/g by the third day of fermentation and reached the inoculation level. On the fifth and seventh days of fermentation, no appreciable change occurred in the level of H. pylori in groups I and II. After heat treatment, the H. pylori levels were below the level of detection. These results suggest that H. pylori can grow during sucuk fermentation and that a heat treatment should be used during sucuk processing to destroy H. pylori.     

Investigation of factors affecting caking tendency of calcium ammonium nitrate fertilizer and coating experiments

Caking of fertilizers is an important problem both to manufacturers and users. Manufacturers must recycle the caked fertilizer to the process resulting in an extra cost and users may have difficulties during the application of the fertilizer to the soil. In the first part of this study major factors which influence caking of a commercial grade calcium ammonium nitrate (CAN) fertilizer were investigated with a laboratory caking apparatus kept in a controlled atmosphere. It was observed that the caking tendency of CAN fertilizer increases almost linearly with pressure exerted on the fertilizer and with moisture content of the fertilizer at a temperature of 35 °C. The results indicate that the phase transition of ammonium nitrate between crystalline forms IV and III plays a significant role in caking of CAN since caking tendency is greatly reduced below the phase transition temperature which occurs at about 32 °C. In the second part of the study, the effectiveness of some coating materials to reduce the caking tendency of CAN fertilizer were tested. Among the materials tested, kieselguhr gave the most satisfactory result under the experimental conditions employed.     

An efficient initial ranging algorithm for WiMAX (802.16e) OFDMA

Ranging is one of the most important processes in the mobile WiMAX standard. Power adjustment, timing offset estimation, and synchronization between a base station (BS) and all users within a cell are done through the ranging process referred to as initial ranging. In this paper, we discuss the details of initial ranging together with some of the proposed algorithms, as well as a novel algorithm to carry out a successful ranging process. Performance curves and computational complexity comparisons are presented. The system performance is evaluated for both additive white Gaussian noise (AWGN) channels and practical multipath fading channels with multiuser interference. It is shown that the proposed algorithm offers a reduced complexity ranging method that can be employed in practical WiMAX-based BSs.     

Market segmentation using service levels in data networks

The objective of this paper is to study a communication system based on aM ^(x)/ D/1 queueing system representing a cell-switch network like Asynchronous Transfer Mode (ATM) network. Network structure consists of a single link modeled as a batch arrival markovian queue with non-preemptive head of the line priority service. Network manager (NM) is assumed to be a decision maker at a Management Information System (MIS) department. This paper establishes the incentive compatible pricing which maximizes the net value of the overall corporation, while the delays have to satisfy the Quality of Service (QoS) guarantees. We obtain structural results for the two priority case in the short run. In equilibrium, we find that the network manager maximizes the price spread between the two priority class services. We prove that as the capacity level increases indefinitely, the market is equally divided among the priority classes. In the first part of the paper, we assume that the users do not respond to network manager’s prices. In the second part, we relax this assumption and look at a leader follower game. Users choose their willingness to pay by deciding on how much value they assign to timely transmission of messages after seeing the prices set by the network manager. Our results indicate that unless there is high enough capacity set upex ante, monopoly network provider cannot price discriminate by offering different quality of service via priority classes. This trade-off between ex ante capacity level choice and ex post price discrimination decision is eliminated if the capacity is set high. It is shown in the network literature that best effort services lead to lower quality of service, in general, for a single service. We show that this holds in multiple priority services as well. We prove that when the capacity is also considered as a decision variable, simultaneous capacity and price setting yields the same optimal level with sequential capacity and price choices.     

Heat transfer from a high temperature safety rod placed in a perforated guide tube and surrounded by an array of cold tubes

In this paper, a simple natural convection heat-transfer model for a safety rod placed in a perforated guide tube is proposed. The geometry is typical of the Savannah River K reactor. The proposed model for the rod and the perforated guide-tube assembly is benchmarked against prototypical test data obtained by Idaho National Engineering Laboratory. The results showed that the proposed model was in good agreement with the experimental data except at very high temperatures where the model slightly underpredicted the rod and tube temperatures. By evaluating the thermal conductivity of the fluid (air) at the wall temperature, the prediction of the high temperature natural convection data was further improved.     

In situ measurement of pitted area by diffuse light scattering

In studies of pitting corrosion, there is often a need for monitoring the size of growing pits in situ as well as the need for a rapid assessment of the extent of pitting damage ex situ on a large number of test specimens. The well-known method of determining surface roughness by diffuse light scattering has been adapted to satisfy both needs. In situ measurements with aluminium alloys immersed in NaCl solutions indicate that early stages of pit propagation can be monitored accurately. Furthermore, measurements on pre-pitted aluminium show that the technique is suitable for rapid, quantitative determinations of a pitted area up to a fraction of 40%.     

Thermodynamic analysis of absorption systems using artificial neural network

Thermodynamic analysis of absorption systems is a very complex process, mainly because of the limited experimental data and analytical functions required for calculating the thermodynamic properties of fluid pairs, which usually involves the solution of complex differential equations. In order to simplify this complex process, Artificial Neural Networks (ANNs) are used. In this study, ANNs are used as a new approach for the determination of the thermodynamic properties of LiBr–water and LiCl–water solutions which have been the most widely used in the absorption heat pump systems. Instead of complex differential equations and limited experimental data, faster and simpler solutions were obtained by using equations derived from the ANN model. It was found that the coefficient of multiple determination (R²-value) between the actual and ANN predicted data is equal to about 0.999 for the enthalpy of both LiBr–water and LiCl–water solutions. As seen from the results obtained, the calculated thermodynamic properties are obviously within acceptable limits. In addition, the coefficient of performance (COP) of absorption systems operating under different conditions with LiBr–water and LiCl–water solutions is calculated. The use of the derived equations, which can be employed with any programming language or spreadsheet program for the estimation of the enthalpy of the solutions, as described in this paper, may make the use of dedicated ANN software unnecessary.     

Effects of tool rotation and pin diameter on fatigue properties of friction stir welded lap joints

The objective of this study was to determine the effects of the tool pin diameter and tool rotation on the fatigue behaviour of friction stir welded (FSW) lap joints. FSW lap joints of AA 5754 aluminium alloy plates were produced by means of a conventional semiautomatic milling machine. Consequently, defect free FSW lap joints were produced on alloy plates at a constant traverse speed but with different tool pin diameter and tool rotation. Therefore, within this study, tool rotation and the tool pin diameter were accepted as variable parameters, while others held fixed. The results of the tests performed, indicate that an optimisation is required for the studied parameters, in order to obtain reasonable fatigue strength. An index, related to tool rotation, traverse speed, pin diameter, and pin height can be identified and used to select optimum parameters for FSW applications.