bluuebunny/crossref_metadata_2025 huggingface dataset:
HighIon/Ioffcurrent ratio graphene field effect transistor: the role of line defect
Authors: Tajarrod Mohammad Hadi , Saghai Hassan Rasooli
Published: October 2015

The present paper casts light upon the performance of an armchair graphene nanoribbon (AGNR) field effect transistor in the presence of one-dimensional topological defects. The defects containing 5–8–5 sp2-hybridized carbon rings were placed in a perfect graphene sheet. The atomic scale behavior of the transistor was investigated in the non-equilibrium Green's function (NEGF) and tight-binding Hamiltonian frameworks. AGNRFET basic terms such as the on/off current, transconductance and subthreshold swing were investigated along with the extended line defect (ELD). The results indicated that the presence of ELDs had a significant effect on the parameters of the GNRFET. Compared to conventional transistors, the increase of theIon/Ioffratio in graphene transistors with ELDs enhances their applicability in digital devices.
Aerobic addition of secondary phosphine oxides to vinyl sulfides: a shortcut to 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides
Authors: Malysheva Svetlana F , Artem’ev Alexander V , Gusarova Nina K , Belogorlova Nataliya A , Albanov Alexander I , Liu C W , Trofimov Boris A
Published: October 2015

Secondary phosphine oxides react with vinyl sulfides (both alkyl- and aryl-substituted sulfides) under aerobic and solvent-free conditions (80 °C, air, 7–30 h) to afford 1-hydroxy-2-(organosulfanyl)ethyl(diorganyl)phosphine oxides in 70–93% yields.
Testing Nordmøre grids on the target and by-catch species of the commercial bottom trawl fishery in the Gulf of Cadiz
Authors: Gamaza Mariángeles , Sobrino Ignacio , Erzini Karim
Published: October 2015

Sorting grids have been tested worldwide in trawl fisheries. Here we report upon the first trials performed using Nordmøre sorting grids with four different bar spacings in the trawl fisheries of the Gulf of Cadiz targeting crustaceans as the main resource. A total of 288 valid hauls and 67 commercial species were caught. Escapement and escape size selectivity were evaluated for the most important target and by-catch species. A decrease in the percentage of biomass escape was recorded with increasing grid spacing for the two target species, deep-water rose shrimp (Parapenaeus longirostris) and Norway lobster (Nephrops norvegicus), from 24% to 8% for the former and from 86 to 9% for the latter, with a 15-mm and 30-mm grid respectively. In general, high escape rates were found for most finfish and cephalopods. For hake (Merluccius merluccius), as the main by-catch species, the results showed an escape rate decreasing from 96% to 71% as the bar spacing increased. Our findings suggest the 30-mm grid would be effective for the deep-water crustacean trawlers but different mitigation measures will be required for other métiers in the multispecies trawl fishery of the Gulf of Cadiz.
Mitochondrial DNA evidences reflect an incipient population structure in Atlantic goliath grouper (Epinephelus itajara, Epinephelidae) in Brazil
Authors: Damasceno Júnio S. , Siccha-Ramirez Raquel , Morales Millke J.A. , Oliveira Claudio , Torres Rodrigo A. , Costa Edvaldo N. , Silva-Oliveira Gláucia C. , Vallinoto Marcelo , Machado Leonardo F. , Tosta Vander C. , Farro Ana Paula C. , Hostim-Silva Maurício
Published: October 2015

The Atlantic goliath grouper is a critically endangered species that inhabits estuarine and reef environments and is threatened primarily by fishing activities and habitat destruction. Despite the urgent need for protection, its genetic conservation status remains unknown. The aim of the present study was to evaluate the gene flow among the populations of the species along the coast of Brazil based on the control region of the mitochondrial DNA. The results indicate low haplotype diversity (0.40-0.86) and very low nucleotide diversity (0.1-0.5%). They also show that the genetic diversity of the species varies considerably along the coast and that this finding may be especially important for the identification of priority areas for its conservation. The population analyses indicate a low but significant degree of genetic structuring (ΦST =0.111), probably due to the occurrence of rare haplotypes at some locations, although the genetic differentiation between sites was not correlated with geographic distance (r=0.0501; p=0.7719), and the shared haplotypes indicate that gene flow occurs among all locations along the Brazilian coast. The results of the pairwise FST indicate a high degree of genetic differentiation between locations. The incipient population structuring detected in the present study is not related systematically to the geological or physical features of the Brazilian coast. The complex interaction of fluctuations in sea level, marine currents, and the reproductive characteristics of the species hampers the identification of the specific role of each of these processes in the gene flow dynamics of the population units of the Atlantic goliath grouper. The low overall levels of genetic diversity, the pairwise FST values and the significant population structuring among groups (ΦCT) identified in the present study all reinforce the critically endangered status of the species and are inconsistent with the presence of a single, panmictic population of groupers on the Brazilian coast. The results of this study suggest that, though it may be incipient, the observed genetic structuring must be taken into account in order to prevent potential problems, such as outbreeding depression, in the management of wild stocks.
Damage-Caused Frequency Shifts in Beams and their Use in Structural Health Assessment
Authors: Gillich Gilbert Rainer , Furdui Horia , Tufoi Marius , Praisach Zeno Iosif , Avram Silviu Razvan
Published: October 2015

Transverse cracks affect the stiffness and consequently the dynamic behavior of beams, by altering the natural frequencies. Actual cracked beam models are not able to explain in-deep the vibration mechanism and, therefore, no mathematical relation able to predict frequency changes due to damage exist. This paper proposes a new damage model which better explain the dynamic behavior of beams with open and closed cracks and a mathematical relation able to predict the frequency changes due to damage. In contrast to actual models, a global approach is used, by considering the influence of the stored energy distribution for each transversal vibration mode. Since the energy loss globally quantifies the state change due to damage, it was possible to replace the cracked beam with an equivalent one having constant but reduced stiffness. Based on it, a relation indicating the frequency drop damage was contrived and tested, by means of the finite element analysis, for various damage types and locations along the beam. Simulations have shown that accurate prediction about the natural frequency shifts can be made with the proposed relation.
On Dynamic Characteristic of Damaged Elastomeric Vibration Isolators
Authors: Nastac Silviu , Debeleac Carmen , Leopa Adrian
Published: October 2015

This paper deals with structural damage identification at vibration isolators with elastomeric-based composite, through continuous or periodical evaluation of behavioral changes of the dynamic characteristics. It has supposed only structural damages of passive isolators, appearing inside the elastomeric core. Theoretical approaches has been provided, computer simulation scenarios regarding some potential critical cases has been developed, and experimental tests has been performed, in order to evaluate main correlation between the levels of structural integrity and the operational performance respectively. Partial results indicate an acceptable sensitivity of this dynamic method with damage detection, and establish next goal of the research in evaluation of the failure imminence and accurately localizing techniques.
Vibration Aspects on Local Light Rail Transportation
Authors: Nagy Ramona , Menyhardt Karoly
Published: October 2015

With the ongoing pace of city development and urban population growth, public transportation is the solution for traffic decongestion. The extensive use of cars causing traffic jams, and more serious pollution, more and more people should travel by public transportation means. In this article, we tested and analysed the vibration characteristics of local tramway transportation by using vibration measurement and analysis system.In spite of increasing exposure to vibrations, transportation supervisors do not concern themselves to the health effects of whole-body vibration or hand transmitted vibrations. Exposure to whole-body vibration is a growing concern in industry, traffic and in other branches of the economy. This harmful physical factor endangers human health not only at work but also in everyday life: in public transportation.The paper concerns with the vulnerability of the human body to vibrations transmitted from trams. The accelerations of the vibrations were measured on the axes (x-, y- and z-axes), and these values were compared to the ones from standards for acceptable human exposure to whole-body vibration.
Mapping the Mechanical Properties of Cancellous Bone from the Femoral Head
Authors: Kun Karla Noemy , Kun Lorand , Nagy Ramona , Menyhardt Karoly , Silaghi-Perju Dana , Nes Cristian Sorin , Bogdan Andor
Published: October 2015

This work presents an experimental program to determine the mechanical properties of cancellous bone in the femoral head as a function of location. To achieve this several specimens of cancellous bone of approximately 10 mm height and 10 mm diameter were obtained from one human femoral head, starting the sampling from its main loading compressive direction. All specimens underwent compression testing in order to determine the mechanical properties of each specimen and thus a properties map of the cancellous bone in the femoral head was obtained. Based on the results a parametric file with material properties was created in order to be used by professionals in finite element analysis programs.
Assessment of Environmental Noise by Harmonica Index – Case Study: The City of Niš
Authors: Prascevic Momir , Mihajlov Darko , Cvetkovic Dragan , Gajicki Aleksandar
Published: October 2015

Noise is a very present environmental nuisance, especially in urban areas. Information on the noise environment of agglomerations over 100,000 inhabitants is now available thanks to the publication of the first strategic noise maps made for the 2002/49/EC European directive. However, it currently remains difficult to understand the environmental noise data because of the used noise indicators expressed in decibel unit, which is complicated to explain and relatively far-removed from the perception of people. Acoucité and Bruitparif, two French organizations specialized for management and organization of urban noise observatories in France, have worked on a proposal for a new index closer to the perception of people. At the end of the HARMONICA project a new environmental noise index called the Harmonica index is suggested. The Harmonica index is an adimensional index with values between 0 and 10. This is why 93% of people surveyed during the project find the Harmonica index easy to understand. According to the Harmonica index the sound environment can be assessed as quiet, noisy and very noisy. The overview of the Harmonica index, the structure of Toots software for the Harmonica index calculation and an example of application of the Harmonica index for assessment of environmental noise in the city of Niš will be given in this paper.
Noise Protection of an Automobile Scrapyard with Car Crushers – A Case Study
Authors: Radičević Branko , Kolarević Milan , Bjelić Mišo , Grković Vladan , Šoškić Zlatan
Published: October 2015

The paper presents a procedure for design of an appropriate noise protection system for an automobile scrapyard. The influenced object is a residential area that borders the scrapyard. The noise impact was estimated by measurements of noise levels in the residential area. Since the measurements revealed that the noise level is above the allowed limits in a wide part of the residential area, a noise map was assembled. The noise maps enabled determination of critical points, with the highest noise levels. Based on calculated noise levels in critical points, characteristics of sources of noise and the relevant noise regulations, a sound barrier was designed as a noise protection mean that will provide a sufficient noise protection of the plant.
Cylindrical Section with Helically Arranged Perforations Inspired by Nature
Authors: Woo Yian Peen , Choong Kok Keong
Published: October 2015

Inspired by the shape and helical pattern of perforations on Cholla skeleton, structural responses of cylindrical sections with multiple perforations have been studied. The common approach to define a helix however, has not been adopted to define the helix lines on the cylindrical sections. This paper proposed a systematic approach to be followed by researchers, for the generation of perforations in multiple helices pattern on surface of cylindrical section. Independent parameters were identified to offer the designers’ ability in taking control when making decision on the desired pattern of perforation along the generated helices covering the surface of the cylindrical section. Rules were imposed to standardize the process and to avoid duplications of similar models under different parameter combinations. Models with perforations along a single helix line were recommended to be generated for consideration prior to those with multiple helices. In this way, understanding the effect of factors found in single helix model can be obtained prior to the examination of the effects of much more complex factors in multiple helices.
Effect of Footfall Induced Vibration on Footbridges
Authors: Aw Jia Hao , Mohammed Parvez Anwar , Elleithy Wael
Published: October 2015

This paper presents the outcomes of investigating the dynamic behaviour experienced by composite footbridges and concrete footbridges when subjected to footfall induced vibration incurred by walking pedestrians. The study focuses on three set of varying parameters including bridge’s deck thickness, span length and width of footbridge. Models are generated and analysed using finite element method. Dynamic responses obtained from the footfall analysis are expressed in term of vertical displacements and accelerations. Data are tabulated and evaluated based on different parameters incorporated; meanwhile comparisons are made between concrete and composite footbridges. It was found that for both composite and concrete footbridges, the displacement and acceleration decrease exponentially with the increase of deck thickness. They also show decreasing trend with the increase of span length. Besides, an increase in displacement and acceleration is observed with the increase of footbridge width.
Estimation of Tsunami Force for Onshore Buildings in the Northwest Coast of Peninsular Malaysia
Authors: Lau Tze Liang , Choong Kok Keong , Majid T.A. , Zakaria Nor Azazi , Ab. Ghani Aminuddin , Inoue Shusaku
Published: October 2015

The northwest coast of Peninsular Malaysia had suffered various extents of structural damage and loss of 68 lives in the unprecedented 2004 Indian Ocean tsunami. Since then, the government of Malaysia concerns about the safety of civil engineering structures and human lives in coastal area. An experimental study was embarked on the formulation of tsunami force for onshore buildings in Peninsular Malaysia. Four downscaled rigid building models with various heights were subjected to probable tsunamis with three nominal wave heights and flow velocities. The wave pressures at front and back faces of building model were measured. The findings show that the front face wave pressure measured from the experiment is in good agreement with the wave pressure predicted using the equation proposed by Japanese researchers. The back face wave pressure distribution is found to be slightly higher than the hydrostatic pressure. The pressure distributions at the front and back faces were then proposed for the estimation of tsunami force on buildings in the northwest coast of Peninsular Malaysia.
Influence of Silica Fume Inclusion on the Compressive Strength Development of High Strength Concrete Containing High Volume of Palm Oil Fuel Ash
Authors: Hatem Alani Aktham , Megat Johari Megat Azmi
Published: October 2015

The influence of silica fume (SF) inclusion on the compressive strength development of high strength concrete (HSC) containing high volume of palm oil fuel ash (POFA) has been investigated. A HSC containing 100% ordinary Portland cement (OPC) and another HSC mix with 50% POFA as part of the binder were prepared. Due to the reduction in early strength of the HSC with the inclusion of high volume of POFA in the binary blended binder HSC, attempt was made to partially replace the OPC with SF at 5, 10, 15 and 20%, thus creating a ternary blended binder HSC. The results show that the compressive strength development of the HSC containing high volume of POFA was significantly improved with the inclusion of SF. The ternary blended binder HSC with 15% SF exhibited the highest increase in early age strength, even though it did not surpass the OPC-HSC, and it provided the highest strength at 7 and 28 days in comparison to other HSC mixes. Thus, ternary blended binder containing more than 60% supplementary cementitious material (POFA and SF) could be utilized to produce HSC.
Mechanical Properties of Mortar Modified with Cement Treated Tyre Crumb and Oil Palm Fruit Fibre
Authors: Abdul Aziz Farah Noor , Mohammed Bida Sani , Mohd Nasir Noor Azline , Safiee Nor Azizi , Jaafar Mohd Saleh
Published: October 2015

Addition or replacement of waste tyre in mortars and concretes in lightweight aggregate concrete composites are popular in concrete material research although the mechanical properties of the composite are reduced. Various research studies have been conducted in an effort to improve the mechanical properties of concretes and mortars containing waste tyre particles using chemicals and additives which lead to increase cost. This approach presents an economical and sustainable method, through adding oil palm fruit fibre (OPFF) at 0.5, 1%, and 1.5% by mass of cement content into the matrix and pre-treating the tyre crumb aggregate (0-40%) by volume with cement, in order to improve the properties of the composite. Mechanical properties including compressive strength, split tensile strength and flexural strength were measured on the mortar specimens. Results showed the addition of 0.5% OPFF in 10% treated tyre crumb mortar gives the best improvement in the mechanical strengths of mortar modified with treated tyre crumb.
Modification of Published Prediction Model of Ground Motion due to Sumatra Subduction Earthquakes for the Application in Peninsular Malaysia
Authors: Van Tze Che , Lau Tze Liang , Majid Taksiah A. , Choong Kok Keong , Nazri Fadzli Mohamed
Published: October 2015

Establishment of ground motion prediction model that is able to accurately predict ground motion for Peninsular Malaysia is always a challenge to local researchers due to the paucity of strong ground motion data. In this study, Fukushima and Tanaka (1990) model which was identified as the best prediction model in estimating ground motion in Peninsular Malaysia due to earthquakes originated from Sumatra subduction zone in previous study was modified in order to enhance its performance. Multiple regression analysis was conducted based on supplementation of 212 seismograms, which were produced by 32 subduction events ranging from Mw 5.2 to 9.1 from Sumatra. The modified Fukushima and Tanaka model is expected to perform well in estimating ground motion from NEHRP Class C and D in the distance range of 300 to 1200 km. The appropriateness of the modified model was verified with actual ground motion in Peninsular Malaysia and also through comparison with other published models that are popular in the region.
A Comprehensive Review of Environmental, Physical and Socio-Economic (EPSE) Criteria for Spatial Site Selection of Landfills in Malaysia
Authors: Ahmad Siti Zubaidah , Ahamad Mohd Sanusi S. , Yusoff Mohd Suffian
Published: October 2015

Location of municipal solid waste landfills in Malaysia has been attributed to causing bad odour, dust, litter, unattractive neighbourhoods, groundwater contamination, hazardous waste pollution and etc. Therefore, proper selection criteria are very important in preliminary siting of new landfill to avoid undesirable long-term effects. This article presents a comprehensive review of landfill spatial siting criteria and their frequency of occurrence (ranked order) found in literatures. The highest ranked criterion is the surface water and the lowest is climate/rainfall density. The dissimilarity in the criteria is found to be specifically influenced by published guidelines or policies from respective countries. In addition, group ranking of spatial criteria from frequency study made on Malaysian local literatures shows that wind factor and infrastructure (utilities) has never been considered in landfill site selection process here. These factors cannot be ignored because enhancing the condition of social, economic and environmental efficiency is part of promoting sustainable development. Subsequently, a benchmarking process of common environmental, physical and socio-economic (EPSE) criteria made with Malaysian landfill siting guideline; National Strategic Plan for Solid Waste Management and Environmental Impact Assessment Guidelines for Municipal Solid Waste and Sewage Treatment and Disposal Project. The bench mark process is useful for research references and its uniformity provides efficient site selection process in solid waste management.
Enhancing BOD/COD Ratio of POME Treatment in SBR System
Authors: Farraji Hossein , Zaman Nastaein Q. , Abdul Aziz Hamidi , Ashraf Muhammad Aqeel , Mojiri Amin , Mohajeri Parsa
Published: October 2015

Palm oil mill effluent (POME) contains high biological oxygen demand (BOD) and chemical oxygen demand (COD) Agra base wastewater is the concern of biodegradable treatment methods. Consequently, the BOD / COD ratio has a significant effect on the biodegradability of wastewaters. This study investigates effects of aerated sequencing batch reactor (SBR) system augmented by zeolite used for treatment of POME. Not only, the BOD / COD ratio increased from 0.11 in raw POME to mean 68.15% increase after aeration in the SBR system, but also, the most obvious finding to emerge from this study is that, aerated SBR could be considered as an effective method for enhancing BOD/COD ratio for qualifying post treatment by biotreatment methods.
Influence of Hydraulic Conductivity and Organic Matter Content in Different Bioretention Media on Nutrient Removal
Authors: Goh Hui Weng , Lau Tze Liang , Foo Keng Yuen , Chang Chun Kiat , Zakaria Nor Azazi
Published: October 2015

Bioretention media composition plays an important role in maintaining hydraulic conductivity within appropriate range and treating stormwater runoff to reduce pollution to receiving water bodies. This study investigated 4 types of bioretention media, 2 of which different types of compost and another 2 using shredded newspaper and crushed cockle shell as additives to modify the bioretention media. The objective of the study was to provide insight on hydraulic performance and media characteristics that control bioretention stormwater treatment performance. Results showed that organic matter content has no effect on hydraulic conductivity and nutrient removal performance of the media. Comparison of hydraulic conductivity and nutrient removal showed that reduced hydraulic conductivity (from 250mm/hr to 159mm/hr) increased total suspended solids (TSS) removal of the media (up to 98.5%) but has no effect on total nitrogen (TN) and total phosphorus (TP). The preliminary pollutant test using natural runoff showed that bioretention media enhanced with 10% shredded newspaper performed the best in TN removal (up to 85.3%) and bioretention media enhanced with 10% crushed cockle shell removed the most TP (up to 95.6%).
Performance of some New Bacterial Isolates on Biodegradation of Libyan Light Crude Oil Using Agro-Industrial Wastes as Co-Substrates
Authors: El Mahdi Abdullah M. , Abdul Aziz Hamidi , Abu Amr Salem S. , El-Gendy Nour Sh. , Nassar Hussein
Published: October 2015

Some unfortunate accidents of large amount of oil hydrocarbons have been reported in Mediterranean Sea which has caused severe environmental damage to the area. To safeguard the Libyan coastline and marine ecologysince thousands of human activity such as fishing largely depends on the healthycoastal environment.Twenty crude oil-degrading bacterial isolates were obtained from oil-contaminated sites at Al Hariga Oil Terminal and Nafoora Oilfield. Based on a high growth rate in crude oil and hydrocarbon degradation efficiency, two isolates were selected from the twenty isolates for further analysis. The nucleotide sequence of 16S rRNA gene showed that these isolates are likely Pseudomonas aeruginosa andKocuriapastrius. One of the isolates is a potential Gram-negative Pseudomonas bacterium based on petroleum hydrocarbon degradation efficiency and potent emulsifying activity; thus, this isolate is identified as P. aeruginosa NAF1; the other isolate K. pastrius SAR3 is identified as a Gram-positive bacterium. Corn steep liquor (CSL) and solid waste date (SWD) were used for an in situ molasses technique to enhance bacterial growth and biodegradation efficiency. P. aeruginosa NAF1 exhibited 70% and 76% crude oil degradation in 0.2% (w/v) CSL and SWD in 28 d, respectively. Likewise, K. pastrius SAR3 yielded 68% and 70% crude oil degradation in 0.2% (w/v) CSL and SWD in 28 d, respectively.
The Study of Flow Characteristics of Newtonian and Power-Law Non-Newtonian Fluids by Dam-Break Flow Model
Authors: How Tion Puay , Faiz Abdullah , Zakaria Nor Azazi , Takashi Hosoda
Published: October 2015

The study aims to investigate the flow characteristics of Newtonian and power-law non Newtonian fluids by using the dam-break of finite extent problem. Analytical and numerical studies are carried out to clarify the flow characteristics. In the analytical study, shallow flow equations are used to derive the characteristic in the viscous flow region for both the Newtonian and power-law non-Newtonian fluids. A numerical model based on the Volume of Fluids (VOF) method with higher order numerical scheme is used to verify the analytical findings. The study derived the flow characteristics based on the propagation of front position and the attenuation of flow depth at the dam upstream boundary.
Removal of Suspended Solids, Chemical Oxygen Demand and Color from Domestic Wastewater Using Sago Starch as Coagulant
Authors: Wan Kamar Wan Izatul Saadiah , Abdul Aziz Hamidi , Ramli Siti Fatihah
Published: October 2015

Sago starch has been widely used in industrial fields, especially in food, non-food, and animal feed biotechnology. Malaysia is one of the highest local sources of sago starch. The alternative use of sago starch as a coagulant for domestic wastewater treatment was investigated in this study. The wastewater sample was collected from the Juru Regional Sewage Treatment Plant in Juru, Penang. The studied parameters include the chemical oxygen demand (COD), suspended solids, and color. Standard jar test procedures were conducted. The initial operating conditions were 200 rpm for 3 min of rapid mixing, 40 rpm for 30 min of slow mixing, and 30 min of settling. The optimum conditions included a pH of 7 and dosage of 2000 mg/L, with rapid mixing at 100 rpm for 1 min, slow mixing at 20 rpm for 30 min, and 18 min of settling. The removal rate of COD and color at these conditions was 70%. Simultaneously, 82% of SS was also removed. The results indicated that sago starch has good potential to treat domestic wastewater; the coagulant may also efficiently treat other types of wastewater.
Wave Transmission over the Low-Crested Sand Container Breakwaters
Authors: Teh Hee Min
Published: October 2015

Breakwaters made of sand container is one of the most economical options for wave protection at coastal areas. These breakwaters have been adopted with mixed success at several locations in Malaysia. Nevertheless, the performance of these structure has not been properly studied and documented to date. This study is undertaken to study the wave transmission ability of the submerged sand container breakwater with respect to its width and height as well as the water depth. A number of experiments have been conducted in a wave flume to quantify the wave transmission coefficient of the test models of different layouts when exposed to regular waves. The experimental result has shown that the breakwater is effective in arresting the shorter period waves, particularly in shallow water. The height of the breakwater has to be increased in order to arrest the longer period waves.
Rainwater Availability Assessment for Tourism Development: A Case Study of Turtle Islands Park, Sabah
Authors: Ayog Janice Lynn , Taharin Mohd Radzif , Sheng Tang Zi
Published: October 2015

This study mainly focused on the rainwater availability assessment in Turtle Islands Park, Sabah, Malaysia. Consisting of three small islands, this marine park is home to two endangered turtle species – Green and Hawkbills turtles. This special feature of the islands attracts tourist around the world, thus increasing the demand of freshwater supply for tourism development in the marine park. However, due to the shortage of freshwater from the ground due to salinity intrusion, rainwater is seen to be an alternative in fulfilling the freshwater demand. To evaluate the source of freshwater in these islands, information is obtained from the main users of the water source, which are the Sabah Park officers, the approved tour operator on the islands and the security forces. The rainwater tanks available on the islands are calculated to assess the storing capacity of rainwater. The water demand was estimated by multiplying the number of visitors with the average water usage per visitor. With the existing water tanks, this study found that the Turtle Islands Park has the ability to store 414 m3 of rainwater in Selingaan island, 3.2 m3 in Gulisaan island, and 102.1 m3 in Bakkungan Kechil island. However, the monthly water demand of each island exceeds the existing storage tanks, hence it is proposed that the number of rainwater tanks be increased to harvest as much rainfall as possible for the use of the islands’ inhabitants.
Computational Investigation of Inlet Baffle Height on the Flow in a Rectangular Oil/Water Separator Tanks
Authors: Hussein Haitham A. , Abdullah Rozi , Md Said Md Azlin
Published: October 2015

Gravity Separator Tanks are Used to Separate Oil from Water in Treatment Units. Achieving the Best Flow Uniformity in a Separator Tank will Improve the Maximum Removal Efficiency of Oil Globules from Water. in this Study, the Effect on Hydraulic Performance of Different Inlet Baffle Height inside a Tank was Investigated. some Experimental Tests were Done for Verification the Velocity Profile with Numerical Results Using ADV (Acoustic Doppler Velocimeter). A CFD Programme, Flow 3D Ver.10 was Used in which Finite Volume Method is Used for Solution of Water Flow Equations and RNG Turbulent Model with the Navier-Stokes Equations. the Volume of Fluid (VOF) Method was Used for Tracking of Free Surface in Simulation Program. the Results of the Numerical Simulation Show that the Separation Tank Performance can Be Improved by Altering the Geometry of the Tank and the Effects of Inlet Baffle Height on the Efficiency of the Separation Tank are Investigated via Assessment of the Circulation Zone Volume Variations, and the Uniformity of Flow Values in each Case.
Studying Effect of Riverbank Filtration (RBF) on Ground Water Using ‘Time-Lapse Electrical Resistivity Imaging’ at Kuala Kangsar, Perak
Authors: Mohamad Mohd Hanis , Nawawi Mohd , Adlan Mohd Nordin , Abdullah Khiruddin
Published: October 2015

Riverbank filtration (RBF) is a natural water pre – treatment, safer and cost – effective that uses geology instead of chemicals to pre – treat river water. The process occur during the infiltration process of river water passing through riverbank material towards a production well during a pumping test, where the removal of biological and colloids take place. Abstraction of ground water are required for RBF to occur, hence pumping test were done. As pumping test took place, ground water was in continuous discharging and recharging process throughout time. Objective of this research is to study the dynamic changes of ground water during discharging and recharging process for 72 hours by using time – lapse electrical resistivity imaging (TLERI). Resistivity, which uses current to measure the resistivity of subsurface was used during the pumping test to monitor ground water changes and infiltration of river water during RBF process. Results show significant changes on TLERI data from the first session until the last session. Dynamic changes occurred around the riverbank and production well section while others show less significant changes.
Subsurface Characterization Using Ground and Underwater Resistivity Techniques for Groundwater Abstraction
Authors: Yusoh Rais , Md Said Md Azlin , Mohamad Ismail Mohd Ashraf , Abdul Razak Mohd Firdaus
Published: October 2015

A geophysical method was used in studying the subsurface profile for investigating the aquifer existence at Jenderam Hilir, Selangor, Malaysia. The 2-D electrical resistivity technique is to determine the presence of aquifer suitable for groundwater abstraction. Resistivity was measured through an ABEM SAS 4000 Terrameter and ABEM Terrameter LS. 2-D electrical-imaging resistivity data of subsurface profile for each survey line were calculated inverse modelling, validate by borehole data which showed the lithology: sandy clay to sandy silt sediments more than 3 m deep, composed of alternating layers of silty and sand. The aquifer potential are mostly in silty sand zones which resistivity value should be within 60-800 ohm-m. Based on interpretation, a potential water-bearing aquifer was located at a depth of 3 m and below which is good agreement with interpreted results. 2-D underwater resistivity survey lines were conducted across the ground and river. Resistivity image was interpreted as silty sand under the river bed, which the subsurface aquifer on land has a physical contact with surface water. Result has shown that ground and underwater resistivity technique can be used as alternative method in finding a good location for groundwater abstraction.
The Study of Mengkuang Dam`s Chute Spillway by Physical Modeling
Authors: Che Ismail Che Mohamad Amirus Shafiq , Mohd Arif Zainol Mohd Remy Rozainy
Published: October 2015

This paper presents a case study of water flow over the chute spillway type for the Mengkuang Dam expansion project. It governs the surplus water from the dam to the downstream area. However, flows were driven by gravity along the curvature and vertical direction which cause unpredictable flow direction along the chute. Its cause’s thickening of turbulence, changing the velocity, pressure and depth of the water along the spillway. This study was simulated using a physical model with geometrical scale of 1:20. After some test conducted on the spillway, eleven locations on the spillway were selected for the test based on observation for the study. For each location, there were five points in a line with equal distance. Manometers were installed on six locations of the spillway. The water level, velocity and pressure were measured at every point for 100, 1000, 10000 years and PMF design discharge of the spillway. Several critical occurrences on the spillway such as turbulent and cross-wave were presented in this paper.
Delphi Technique Procedures: A New Perspective in Construction Management Research
Authors: Alaloul Wesam Salah , Liew Mohd Shahir , Zawawi Noor Amila Wan
Published: October 2015

The Delphi technique is a methodology seeks to achieve a consensus among panel of experts. The consensus is gained through a sequence of rounds. The feedback information passed to panelists by questionnaires. The technique applications being progressively involved in construction management (CM) researches and it has been applied widely in many disciplines. This popularity meant that reasonable and accurate results have been gained using Delphi technique. The aim of this study is to analysis monetary Delphi technique as a robust and systematic data collection tool in CM. Discussion and review focused on the procedures of application, cons and pros and the technique key aspects. These key aspects included experts’ selection, anonymity, rounds and feedback; have been investigated through ten published articles in CM. Delphi technique has significant opportunity to be used widely in gaining consensus within CM research. This article provides rigorous guidelines for the technique application in CM to ensure bias elimination and the outcomes validity and reliability.
The Possibility of Building Classification for Mould Threat Using Gas Sensors Array
Authors: Suchorab Zbigniew , Guz Łukasz , Łagód Grzegorz , Sobczuk Henryk
Published: October 2015

Mould risk is an increasing problem in current housing branch. Mould is considered to be one of the most important features of Sick Building Syndrome. In most cases it is caused by the increased moisture of building barriers and improper humidity of indoor air. In old buildings it is caused by improper raising techniques, lack of isolation against moisture and insufficient building materials applied for construction. Modern housing also suffers problem of mould risk which is connected to introducing of the new materials and technologies for external envelopes of the buildings. These often increase the tightness of the buildings and cause improper performance of natural ventilation systems, which makes suitable conditions for mould to grow.In the paper there is proposed an attempt to evaluate mould risk in the buildings using e-nose, being a gas sensors array which consists of eight metal oxide semiconductor (MOS) gas sensors. This device is commonly applied for air quality assessment in environmental research. First part of the article is a description of e-nose technology and its possible applications in constructions. The second part shows the exemplary e-nose readouts of indoor air sampled in clean reference rooms and threatened with mould development. Obtained multivariate data are processed and visualized using a Principal Component Analysis (PCA).
Thermogravimetry of Portland Cement from Argentina and Czech Republic
Authors: Trník Anton , Scheinherrová Lenka , Kulovaná Tereza , Pavlík Zbyšek , Rahhal Viviana , Irassar Edgardo Fabian , Černý Robert
Published: October 2015

We study the hydration and pozzolanic reactions of cement pastes made from Argentinian and Czech Portland cements as a function of age, using thermogravimetry. The measurements are done for 2, 7, 28, and 90 days cured samples in order to monitor the rate of hydration. The investigation is performed in the temperature range from 25 °C to 1000 °C with a heating rate 5 °C/min in an argon atmosphere. The mass change during the decomposition of calcium silicate hydrate gels, portlandite, and calcite are determined, and the changes in the portlandite amount are estimated in dependence on the time of hydration.
Thermal Properties of Mannitol Derivative
Authors: Trhlikova Lucie , Zmeskal Oldrich , Prikryl Radek , Florian Pavel
Published: October 2015

Mannitol is an alcoholic sugar that is commonly used in the food industry. It is a white, odorless crystalline powder. Its melting temperature is about 168 °C. It is possible to be used also for the accumulation of energy in the heat exchangers based on oils. On its basis is sold a product PlusICE A164 of company PCM Products Ltd. (T = 164 °C, cp = 2.42 kJ.K-1 kg-1). Thermal properties of the material in both, solid and liquid phase were investigated for this purpose in terms of potential applications. Temperature dependence of thermal parameters (thermal diffusivity, thermal conductivity, and specific heat) were determined using a transient (step-wise) method. Fractal model of heat transport was used for the determination of thermal parameters. This model is independent on the geometry and on the type of the sample heating, and includes heat losses too. The experiment confirms the phase change temperature about 168 °C.
The Influence of Texture and Firing on Thermal and Elastic Properties of Illite-Based Ceramics
Authors: Antal Daniel , Húlan Tomáš , Trník Anton , Štubňa Igor , Ondruška Ján
Published: October 2015

The texture in illite-based ceramics was introduced by spreading a large number of thin layers of a wet plastic mass one on top of the other. The basal planes of the plate-like illite crystals are predominantly oriented parallely with the direction of spreading. The samples were fired at different temperatures ranging from room temperature up to 1100 °C with a heating rate of 5 °C/min, then freely cooled and measured at room temperature. We determined Young modulus (E), thermal diffusivity (a) and relative dimension changes (Δl/l0) in two directions: parallely to the basal planes (a subscript ||) of the illite crystals and perpendicularly to these planes (a subscript ⊥). It was found that the ratio E|| / E⊥ ≈ 2.9 and a|| / a⊥ ≈ 2.0 up to 900 °C. Above 900 °C, the values of E and a increase due to sintering, and the differences between the values measured in the two directions decrease. In the case of the thermal diffusivity these differences do not disappear even after firing at the temperature of 1200 °C.
Electrically Inactive Dopants in Heavily Doped As-Grown Czochralski Silicon
Authors: Stockmeier Ludwig , Elsayed Mohamed , Krause-Rehberg Reinhard , Zschorsch Markus , Lehmann Lothar , Friedrich Jochen
Published: October 2015

To determine the electrically inactive fraction of As or P in heavily doped as-grown Czochralski Si 4-point resistivity and SIMS measurements were carried out. No clear trend for the electrical inactive fraction was found with an increasing dopant concentration, though a mean electrical inactive fraction of 11.5% for As doping could be determined.Experimental results on a dopant-vacancy complex in as-grown Si are scarce, hence temperature-dependent positron annihilation lifetime spectroscopy (PALS) was carried out on several heavily As and P doped as-grown Si samples. The measured average positron annihilation lifetime τav is between 218 ps and 220 ps. No temperature dependent effect on τav could be observed. Therefore, it can be concluded that in the studied doping range the dopant-vacancy complexes do not exist. The reason for the inactivation of the dopant has to be found elsewhere. A possible explanation can be the formation of dopant precipitates.
Low Temperature Activation of Grown-In Defects Limiting the Lifetime of High Purity n-Type Float-Zone Silicon Wafers
Authors: Grant Nicholas E. , Rougieux Fiacre E. , Macdonald Daniel
Published: October 2015

We investigate the recombination activity of a bulk silicon defect limiting the lifetime of high quality n-type float-zone (FZ) silicon wafers. By isochronal annealing between 200 and 1100 °C, a defect was found to become activated upon annealing at 450–700 °C, causing an order of magnitude reduction in the bulk lifetime. From photoluminescence imaging, it was evident that recombination active circular patterns were present in these low lifetime samples, suggesting the defect (s) originates from the growth conditions of the ingot. When the samples were passivated by SiNx:H films, a substantial improvement in the bulk lifetime resulted, which we postulate occurred due to hydrogenation of the bulk defects. In contrast, when the samples were annealed at high temperatures (800–1100 °C), the circular recombination active patterns were removed, and the bulk lifetime improved, with the highest lifetime achieved at an annealing temperature of 1100 °C. The experimental results suggest that the defect limiting the lifetime in this FZ material is related to a lattice-impurity defect, which can be permanently annihilated upon annealing at >1100 °C.
Determination of the Free Gibbs Energy of Plate-Like Precipitates of Hydrogen Molecules and Silicon Vacancies Formed after H+ Ion Implantation into Silicon and Annealing
Authors: Cherkashin Nikolay , Darras Francois Xavier , Claverie Alain
Published: October 2015

Hydrogen implantation at room temperature into monocrystalline silicon leads to the formation of complex defects and also to the appearance of in-plane compressive stress. During annealing hydrogen atoms and vacancies co-precipitate into platelets lying on two types of habit planes. These platelets play a decisive role in the fracture of the material that can occur during further annealing and which is used for the manufacture of SOI wafers. Thus, their stress assisted nucleation mechanism has to be well understood. Here, we develop a formalism based on the Volmer’s model which allows calculating the variation of the free Gibbs energy of the system following the nucleation of a platelet. In an unstressed crystal, this energy only relies on the habit plane of the platelet. When the system is under stress, this energy also depends on a term coupling this stress and the strain field generated by the platelet. Because those energies control the nucleation rate of the platelets variants, we could calibrate our model using the transmission electron microscopy observations of the platelets occurrences as a function of depth and, thus, as a function of the magnitude of the intrinsic stress and the angles between the stress direction and Burgers vectors of the considered platelets. These experimental distributions allowed us adjusting the parameters describing the Gibbs free energy of platelets.
Direct Observations of Fe Impurities in Si with Different Fermi Levels by Mössbauer Spectroscopy
Authors: Ino Yuji , Tanaka Kiyotaka , Sakata Kazumasa , Yoshida Yutaka
Published: October 2015

The charge states of Fe interstitial atoms in Si are investigated by Mössbauer spectroscopy. The spectra of 57Fe-diffused Si wafers are measured directly after the deposition at room temperature. The Fermi levels are changed by applying the external voltages to a Schottky junction, and by using different Si wafers with different dopant concentrations, providing different fractions of interstitial Feint0 and Feint+ Mössbauer components which correspond to the isomer shifts of 0.40 and 0.80 mm/s, respectively.