134 research outputs found

    Evaluation of Double Loop IC Module for Inductive Coupled Fed RFID Tag Wire Embedded Antenna

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    This paper presents an evaluation on double loop integrated circuit module for inductive couple fed RFID Tag. The inductive couple feed gives advantage especially for flexible wire embedded antenna in controlling the manufacturing varians as the chip is not directly connected to the antenna. Thus electrostatic discharged effect and manufacturing errors can be minimized. An inductor loop is directly connected to the RFID chip before it is placed to indirectly coupled the energy from a meandered dipole antenna. The coupled energy should be enough to turn on the chip to communicate with the reader. The inductive coupled energy is achieved by manipulating the near field magnetic field between the antenna body and the inductor loop. To evaluate the performance, the antenna and the inductive feeding loop is designed to operate at RFID UHF band (860 MHz – 960 MHz) and simulated using CST software. The antenna body impedance is evaluated to match the impedance of the chip and the loop. It is confirmed that the double loop inductor has higher inductance values and thus should be counted in conjugate impedance between the antenna body and the chip module. The tag with overall dimension of 60 mm x 16 mm can be read at distance at least 9 meters through out the band

    Establishment of a comprehensive epilepsy center in Pakistan: initial experiences, results, and reflections

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    Background. Developing countries, home to 80% of epilepsy patients, do not have comprehensive epilepsy surgery programs. Considering these needs we set up first epilepsy surgery center in Pakistan. Methods. Seventeen teleconferences focused on setting up an epilepsy center at the Aga Khan University (AKU), Karachi, Pakistan were arranged with experts from the University of Alberta Hospital, Alberta, Canada and the University of West Virginia, USA over a two-year period. Subsequently, the experts visited the proposed center to provide hands on training. During this period several interactive teaching sessions, a nationwide workshop, and various public awareness events were organized. Results. Sixteen patients underwent surgery, functional hemispherectomy (HS) was done in six, anterior temporal lobectomy (ATL) in six, and neuronavigation-guided selective amygdalohippocampectomy (SAH) using keyhole technique in four patients. Minimal morbidity was observed in ATL and, SAH groups. All patients in SAH group (100%) had Grade 1 control, while only 5 patients (83%) in ATL group, and 4 patients (66%) in HS group had Grade 1 control according to Engel\u27s classification, in average followups of 12 months, 24 months and 48 months for SAH, ATL, and HS, respectively. Conclusion. As we share our experience we hope to set a practical example for economically constrained countries that successful epilepsy surgery centers can be managed with limited resources

    The evaluation of shear deformation for contact analysis with large displacement

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    A common problem encountered in the study of contact problem is the failure to obtain stable and accurate convergence result when the contact node is close to the element edge, which is referred as "critical area". In previous studies, the modification of the element force equation to apply it to a node-element contact problem using the Euler-Bernoulli beam theory [1]. A simple single-element consists two edges and a contact point was used to simulate contact phenomenon of a plane frame. The modification was proven to be effective by the convergeability of the unbalanced force at the tip of element edge, which enabled the contact node to "pass-through", resulting in precise results. However, in another recent study, we discover that, if shear deformation based on Timoshenko beam theory is taken into consideration, a basic simply supported beam coordinate afforded a much simpler and more efficient technique for avoiding the divergence of the unbalanced force in the "critical area". Using our unique and robust Tangent Stiffness Method, the improved equation can be used to overcome any geometrically nonlinear analyses, including those involving extremely large displacements

    Development of an improved crack propagation model for corrosion-induced cover cracking in RC structures

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    During the last two decades, reinforced concrete (RC) has been extensively used in most of the world as one of the common construction material due to its advantages and durability. However, RC structures exposed to marine environments are subjected to chloride attack. Chlorides from seawater penetrate into RC structures are not only causing severe corrosion problems but also affect the durability and serviceability of such structures. This paper investigates the influence of transverse reinforcement and spacing of reinforcing bars on concrete cover cracking of two-way RC slab specimens using accelerated corrosion tests. The experimental program involved the testing of four RC slab specimens and was generally designed to observe the crack width and the time of crack to propagate. An improved model for predicting the timing of crack propagation based on the experimental data was then developed

    Study of dissolved copper (ii) speciation at Pulau Pangkor, Perak, Peninsular Malaysia

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    The profile of seawater samples was analyzed from a few selected stations at Pulau Pangkor, Perak for dissolved copper speciation analysis in order to determine the concentration level of toxic cupric ions (Cu ²⁺ ) in seawater. The concentration of natural organic Cu(II)-ligand binding (CuL) and its conditional stability constant (Log K’CuL) in each sample was determined by using competitive ligand exchange–adsorptive cathodic stripping voltammetry (CLE-AdCSV) method with salicylaldoxime (SA) as competitive ligand. Our present data have recorded a total dissolved Cu concentration [dCu] ranged between 3.14–7.12 nM and 3.10–9.11 nM at a surface layer and at 15-meter depth, respectively. An organic ligand concentration [CuL] at the surface layer ranges between 4.41-13.25 nM, with its conditional stability constants (log K'CuL) between 11.55-12.17. However, at 15-meter depth, the [CuL] was recorded between 5.90-11.14 nM with log K'CuL ranged 10.93-12.84. On the other hands, a free Cu ion activity, pCu (pCu = −log[Cu ²⁺ ]), was ranged from 8.97-10.35, and was slightly less compared to the pCu values that have been recorded in other coastal waters (>12). The free [Cu ²⁺ ] was ranged between 10 ⁻⁹ –10 ⁻¹¹ pM, which was slightly below the toxicity threshold (10 ⁻⁸ pM). This initial study has suggested that dCu was largely complexed by organic ligands (>99.6%), both strong organic ligand (L1: LogK>12) at surface and weak organic ligand (L2: LogK<11) at the deeper layer. The presence of these two classes of ligands have buffering the free Cu ²⁺ ions, yielding a non-toxic Cu to the microorganisms

    Characterization of Enzyme Produced from Pseudomonas Putida for BTX (Benzene, Toluene & Xylene) Treatment in Petrochemical Industry Wastewater System

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    One of the big challenges in petrochemical industries is waste management. Currently, huge money was spending on the disposal of the waste. Industries are trying hard to find an alternative method to reduce the cost and improve the effectiveness of current waste management including treatment efficiency. Most of petrochemical wastes are containing benzene, toluene and xylene (BTX) which are very harmful to environment and living organisms. Common method used to separate the BTX from the waste are by using liquid-liquid and stripping process. One of the alternative to treat BTX is biological treatment method that used the natural capability of microorganisms to degrade to less harmful product is been applied. Some of examples are Pseudomonas Putida. (P. putida), Rhizobium, and Agrobacterium. P. putida is selected in this study for the biological treatment of BTX in petrochemical wastewater because it can produce an enzyme that has the capability of breakdown the aromatic hydrocarbon to carbon dioxide (CO2) and water (H2O). The main objective of this study is to produce and extract the enzymes produce, characterised the enzymes. This study also to investigate the effect of different concentration on the treatment as well as the growth of the bacteria. The enzyme is purified using salt precipitation and analysed using SDS_PAGE technique. UV-Vis is used to study the growth of the bacteria in the culture stock by measuring its optical density. The concentration of BTX was varied to determine the effect of the concentration on the percentage removal and the growth of P. putida. Enzymes detected or purified in this study was benzene reductase. Other expected enzymes were not able to be purified or analysed. It was found that in this experimental study, the removal of benzene is at 74% to 80%. The removal of toluene is at 62% to 75%. The removal of xylene is at 23% to 42%. Increasing the concentration of contaminants will reduce the removal capabilities

    Mapping on slope seepage problem using Electrical Resistivity Imaging (ERI)

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    The stability of slope may influenced by several factors such as its geomaterial properties, geometry and environmental factors. Problematic slope due to seepage phenomenon will influenced the slope strength thus promoting to its failure. In the past, slope seepage mapping suffer from several limitation due to cost, time and data coverage. Conventional engineering tools to detect or mapped the seepage on slope experienced those problems involving large and high elevation of slope design. As a result, this study introduced geophysical tools for slope seepage mapping based on electrical resistivity method. Two spread lines of electrical resistivity imaging were performed on the slope crest using ABEM SAS 4000 equipment. Data acquisition configuration was based on long and short arrangement, schlumberger array and 2.5 m of equal electrode spacing interval. Raw data obtained from data acquisition was analyzed using RES2DINV software. Both of the resistivity results show that the slope studied consists of three different anomalies representing top soil (200 – 1000 Ωm), perched water (10 – 100 Ωm) and hard/dry layer (> 200 Ωm). It was found that seepage problem on slope studied was derived from perched water zones with electrical resistivity value of 10 – 100 Ωm. Perched water zone has been detected at 6 m depth from the ground level with varying thickness at 5 m and over. Resistivity results have shown some good similarity output with reference to borehole data, geological map and site observation thus verified the resistivity results interpretation. Hence, this study has shown that the electrical resistivity imaging was applicable in slope seepage mapping which consider efficient in term of cost, time, data coverage and sustainability

    Sposol: 5 In 1 Smart Portable Solar Light

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    Smart Portable Solar Light is a project based on a circuit obtained through the internet connection.A few modifications have been done to the original circuit; original circuit uses eight LEDs while this project only uses one main LED.The main source of this system is harvest form the sun.The sun’s radiation is converted to electrical energy that is supplied to a battery,which acts as a power storage for the system.Another set of batteries is used as the structure of the lamp is design to be portable

    Positive relationships between association strength and phenotypic similarity characterize the assembly of mixed-species bird flocks worldwide

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    Competition theory predicts that local communities should consist of species that are more dissimilar than expected by chance. We find a strikingly different pattern in a multicontinent data set (55 presence-absence matrices from 24 locations) on the composition of mixed-species bird flocks, which are important sub-units of local bird communities the world over. By using null models and randomization tests followed by meta-analysis, we find the association strengths of species in flocks to be strongly related to similarity in body size and foraging behavior and higher for congeneric compared with noncongeneric species pairs. Given the local spatial scales of our individual analyses, differences in the habitat preferences of species are unlikely to have caused these association patterns; the patterns observed are most likely the outcome of species interactions. Extending group-living and social-information-use theory to a heterospecific context, we discuss potential behavioral mechanisms that lead to positive interactions among similar species in flocks, as well as ways in which competition costs are reduced. Our findings highlight the need to consider positive interactions along with competition when seeking to explain community assembly
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