Applied Mechanics and Materials Vol. 833

Abstract: This work studied on the kinetics of Vitamin C extraction from banana peel at different solvent/solid concentration and temperature. Musa Acuminata was ground into smaller sizes before contacted with methanol as a solvent in an ultrasonic bath. To study the effect of solvent/solid ratio, 4.5, 5.0 and 10.0 ml/g ratio were used for the extraction at fixed temperature. Then, the temperature was varied with the heating element available in the ultrasonic bath at 30, 45 and 60 °C, to study the effect of temperature on the extraction kinetics. It was found that high solvent/solid ratio (10 ml/g) provides more solute-solvent contact and prevents the extracted Vitamin C from coming into contact with the air. Besides, higher temperature (60 °C) contributes sufficient kinetic energy for Vitamin C distribution in the solvent which is important to prevent degradation with air. The best fitted kinetic model for Vitamin C extraction from Musa Acuminata is Ana et al. (2007) with equilibrium concentration of 0.05 g/L and 0.40 g/L.hr extraction rate.

Abstract: The results show the effect of polymer modification on the behavior of Ca (OH)₂ in steel fiber reinforced concrete. The polymer modified concrete were prepared using acrylic emulsion polymer at various polymer-cement ratios; they were tested for mechanical strengths, moulded into specimens and cured. The cured specimens were subjected for compressive strength, flexural strength, splitting tensile strength and modulus of elasticity. The small specimens that moulded were subjected to X-ray diffraction (XRD). From the test results, it is concluded that formation of Ca (OH)₂ in the polymer modified concrete reinforced with steel fiber is reduced possibly because of the absorption of Ca (OH)₂ on polymer films formed in the concrete. The extent of reduction in the quantity of Ca (OH)₂ depends upon the polymer-cement ratio, polymer type or both. Generally SFRPMC of mix 43 with 2.5% polymer-cement ratio were found to be more effective than other SFRPMC with 1.0% and 4.0% acrylic emulsion polymer in reducing the quantity of Ca (OH)₂ in SFRPMC. The cement modifiers did not cause any detrimental effect on the degree of hydration as in SFRPMC therefore, does not provide a proper means for predicting their degree of hydration.

Abstract: Normally mechanical chiller supplies chill water temperature at a higher operating temperature to charge a radiant cooling system in building. Other source of cooling is possible since the operating temperature for radiant cooling is limited by the air dew point temperature. This study investigates cooling of water through long wave radiation to the night sky in Kuching Sarawak, Malaysia and utilise this water for radiant cooling purpose. Mathematical model were developed to predict the cooling power of the nocturnal cooling over typical metal roof and was compared to an experimental data. The measurement from the test model verified the predicted data and a yearly potential from nocturnal cooling in this region was established. The amount of cooled water generated from this night cooling system was also calculated. Results showed that an average of 73 W/m² nocturnal cooling power is possible in this region.

Abstract: Electrical resistivity (ER) of cement based materials (CBM) is an important measurement that indirectly relates to the durability of CBM. This study investigates the correlation between ER of CBM namely concrete with water-to-cement (w/c). As one of CBM hydration parameters w/c is an important parameter that contributes to variations of ER. The results of this study showed that different w/c can be used as indication for the setting characteristics as well as the pore structure of the concrete. ER is obtained by applying current into the concrete and measuring the response voltage during concrete hydration period of 28 days. Two aspects were also being considered in this study: (i) test specimen size and (ii) spacing between the probes. Results show the direct correlation between ER and test specimen sizes and spacing between the probes.

Abstract: Chip manufacturing technologies have been a key to the growth in all electronics devices over the past decade, bringing added convenience and accessibility through advantages in cost, size, and power consumption. Using recent CMOS technology, LFSR is implemented until layout level which develops low power application. One of the most frequent uses of a LFSR inside a FPGA is as a counter. Using a LFSR instead of a binary counter can increase the clock rate considerably due to the low routing resource required to produce the next state logic. This paper explores the LFSR using different architecture in a 0.18μm CMOS technology. There are 3 type architecture implemented into LFSR which is NAND gates, pass transistor and transmission gates. Those LFSR are compare in term of CMOS layout, hardware implementation and power consumption using Mentor Graphics tools. Thus, it provides analysis of LFSR for low power application in CMOS VLSI.

Abstract: A single event upset (SEU) or soft error is defined as a temporary error on digital electronics due to the effect of radiation. Such an error can cause system failure, e.g. a deadlock in an asynchronous system or production of incorrect outputs due to data corruption. With increasing system complexities and integration scale, transistors have become more vulnerable to soft error, necessitating analysis of soft error in circuits, which is the focus of this thesis. Vulnerability of circuits to soft errors is further aggravated by several factors, such as variations in the process and temperatures. Process variations are inaccuracies in the manufacturing process which may lead to deterioration of circuit performance and increase in power consumption. Temperature variation degrades the threshold voltage, carrier mobility and velocity saturation of transistor. As a result of degrading carrier mobility, the drain current becomes lower thus increasing the sensitivity of the node to SEU.

Abstract: Please make the page settings of your word processor to A4 format (21 x 29,7 cm or 8 x 11 inches); with the margins: bottom 1.5 cm (0.59 in) and top 2.5 cm (0.98 in), right/left margins must be 2 cm (0.78 in)This paper is based on a project is entitled “Implementation of a Test Bed for Supercapacitor Testing and Evaluation” that is intended to perform tests and evaluate the behavior and characteristics supercapacitors. The test bed can perform charging and discharging of different types of supercapacitors. This implementation serves to automatically acquire the data from the testing procedure and plot in real time the graphs for monitoring the charging and discharging behaviour. From there, the test bed can determine the two significant characteristics of the supercapacitor, which are the capacitance value in Farad and the equivalent series resistance (ESR) in Ohm. The capacitance value is obtained using the measurements taken during the discharging process while the ESR is determined by measurements taken when it is charged using a constant current. The test bed can select between different modes of charging depending of the type of supercapacitor put to test. It can measure and evaluate capacitance ranges from 0.1F to 10F. This paper will discuss the methodologies that the test bed implements for testing the supercapacitors, and the results obtained from evaluation of several types of supercapacitors. We shall be able to publish your paper in electronic form on our web page http://www.scientific.net, if the paper format and the margins are correct. Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc. It is found the test bed can approximately read the values of supercapacitors that have low ESR ranges.

Abstract: Recent technology requires multistandard Radio Frequency (RF) chips for multipurpose wireless applications. In RF circuits, a low-noise amplifier (LNA) plays the key role in determining the receiver’s performance. With CMOS technology scaling, various designs has been adopted to study circuit’s characteristic and variation. In this paper, we present the results of scalable wideband LNA design based on complementary metal oxide semiconductor (CMOS), with its variance study. The design was fabricated in 180nm, 90nm, 65nm and 40nm CMOS technology.

Abstract: This paper presented the design of integrated filter antenna for 2.4GHz microwave applications. Open loop resonator bandpass filter is designed to increase the bandwidth of the antenna by producing the range of frequencies that can be accepted by the antenna structure. Direct connection between the filter structure and antenna may cause impedance mismatch and deteriorates the performance of both antenna and filter. Thus, by integrating both filter and antenna into a single module, the overall performance can be improved and increase the efficiency of the system with improved bandwidth. The design used FR4 with dielectric constant of εr = 4.7 with substrate thickness of 1.6mm. It is shown that the simulation result for the proposed integrated filter antenna produce return loss, S₁₁=-20.009dB, gain of radiation pattern is 3.36dB and an increase of bandwidth to approximately 3.74% compare to the single structure antenna.

Abstract: This This paper addresses a novel technique in implementing hybrid parallel-prefix adder (HPA) incorporating prefix-tree structure with Carry Select Adder (CSEA). Ling’s algorithm is used to optimise the pre-processing blocks (white nodes) and intermediate Generate-Propagate blocks (Black nodes) of the prefix tree to minimise the congestion of wires which contributes to reduction in chip size and to improve performance. The resulting prefix-tree arrangement is then merged into a sequence of modified CSEA. Experimental results show that HPA has speed improvement of 62% and 13% power reduction in comparison of the traditional Carry Look-Ahead Adder (CLA).