bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD CHARACTERIZATION OF FLOW PATTERN AROUND ENDOTHELIAL CELL IN DENGUE INFECTION WITH PLASMA LEAKAGE
Authors: Kaliwantoro Nur , Soesatyo Marsetyawan HNE , Indarto Indarto , Juffrie Mohammad , Dharmastiti Rini , Tauviqirrahman Mohammad
Published: October 2015

Plasma leakage is the pathological hall mark in dengue infection and may cause fatal condition to the patients. In this paper, the CFD (computational fluid dynamic) model is adopted to characterize the flow on the endothelial cells surface with plasma leakage based on in vitro experiments of HUVEC (human umbilical vein endothelial cell) culture on the permeable membrane. The computational domain used is a simplified model of single cell. At the leading edge of the domain and among the membranes, the gaps are modeled as a representation of cell-cell junction breakdown caused by dengue virus infection.  The result shows that at the leading edge , the fluid starts to move more quickly and increases to the maximum value at the middle of the cell and then drops to zero at the trailing edge. From the physical point of view, this result describes that there is a variation of the values of the wall shear stress due to the velocity gradient. These results can be considered as a first step to develop the ways of the prevention of the dengue infection through manipulation the shear stress to reduce the potency of dengue virus to attach the cell surface.
BIOMODELLING OF CRANIO-MAXILLOFACIAL IMPLANT APPLYING OPEN SOURCE SOFTWARE
Authors: Abdullah Johari Yap , Rajion Zainul Ahmad , Omar Marzuki
Published: October 2015

Advances in craniofacial medical imaging has allowed the 3D reconstruction of anatomical structures for medical applications, including the design of patient specific implants based on computer-aided design and computer-aided manufacturing (CAD/CAM) platforms. This technology has provided new possibilities to visualize complex medical data through generation of 3–dimensional (3D) physical models via additive manufacturing that can be eventually utilised to assist in diagnosis, surgical planning, implant design, and patient management. Although the study on the construction of cranio-maxillofacial implant based on computer modelling and advanced biomaterial are growing rapidly from other parts of the world, however, in Malaysia is scanty, especially with open source application. For this reason, it leads us to embark in a study to produce a potential locally cranio-maxillofacial implant with equivalent standard as compared to the commercially available product applying open source software. As part of four sub-projects of USM Research University Team (RUT) project, the authors had investigated and applied open source software to perform image processing of CT data, to segment the region of interest of anatomical structures, to create virtual 3D models, and finally to convert the virtual 3D models to a format that compatible for additive manufacturing platform. Further research is ongoing to investigate on designing the cranio-maxillofacial implant using open source CAD software using suitable biomaterial.
PROSTHETIC EAR RECONSTRUCTION APPLYING COMPUTER TOMOGRAPHIC (CT) DATA AND ADDITIVE MANUFACTURING TECHNOLOGIES
Authors: Mohamed Nor Azura , Rajion Zainul Ahmad
Published: October 2015

The treatment of auricle defect can be by surgical or prosthetic ear rehabilitation depending on the condition.  Current practice by surgeon for prosthetic ear rehabilitation require patient to go for osseointegrated craniofacial implant surgery for retention of the prosthetic ear.  Impression technique play a vital role in accurate reproduction of affected and unaffected ears, orientation of the ear during wax try in and fabrication of ear prostheses. Traditionally, the wax pattern was created from the impression taken from patient and the final prosthesis is processed with silicone material.  This conventional method has always been time consuming, massive work and caused discomfort to patient.  Moreover the accuracy of the final prosthetic sometimes was not satisfied. Improvement in medical imaging technology whereby data from computerized tomography (CT) in 2D format can be converting to 3 dimensional images gave tremendous view for surgeon to visualize the result.  A new and impressive advance in the development of additive manufacturing technology is now being able to be applied in medical field.  The widespread use of computer-aided design (CAD) combine with computer aided manufacturing (CAM) produced the momentum and desire to translate the 3-D images into physical models. Studies and research have indicated the viability of using medical imaging technology, computer aided design (CAD) and additive manufacturing techniques in prosthetics.  This paper proposed a novel method of fabricating the prosthetic ear applying mirror image technique to reconstruct the missing ear, and then fabricate the 3D model of the prosthetic ear using Stereolitography (SLA) technology that will become the master mold to produce the final prosthetic ear.  This method eliminates the traditional wax pattern procedure. A clinical study is done onto a patient in HUSM and comparison is made between traditional method vs new approach using computer aided technology.  Result showed that there is significant different between traditional and new approach design.  The new method also shows time reduction during design and fabrication stage.
MECHANICAL AND MORPHOLOGICAL PROPERTIES OF POLYAMIDE 12 COMPOSITE FOR POTENTIAL BIOMEDICAL IMPLANT: INJECTION MOLDING AND DESKTOP 3D PRINTER
Authors: Tuan Rahim Tuan Noraihan Azila , Md Akil Hazizan , Abdullah Abdul Manaf , Mohamad Dasmawati , Ahmad Rajion Zainul
Published: October 2015

Fused filament fabrication is a filament based rapid prototyping process, which offers the possibility of new polymer material for invention of biomedical implant. This study represents an investigation on a preparation and characterization of new polyamide 12 reinforced with 20 wt% of zirconium dioxide and hydroxyapatite by desktop 3D printer in comparison with conventional manufacturing method, injection molding. Polyamide 12 composite was compounded, pelletized and filament-extruded prior to apply to a 3D printer. Sample prototypes from the new polyamide composite have been successfully made and tested. Mechanical (flexural and impact) and morphological properties were evaluated and compared. From the results, the printed polyamide composite exhibited lower mechanical properties than injection molded due to the formation of porosity, laminate weakness and low pressure during printing. Although the mechanical properties of printed parts were lower than molded parts, but the capability of 3D printer to fabricate any customized 3D object could lead to the bright future and great contribution in this area, while at the same time many improvements can be made for the future works.
IDENTIFICATION OF VAGINA AND PELVIS FROM IRIS REGION USING ARTIFICIAL NEURAL NETWORK
Authors: A.J. Nor’aini , Z. A. Syahrul Akram , S. Azilah
Published: October 2015

Iris recognition not only can be used in biometrics technology but also in medical application by identifying the region that relates to the body part.  This paper describes a technique for identification of vagina and pelvis regions from iris region using Artificial Neural Network (ANN) based on iridology chart whereby the ANN process utilized Feed Forward Neural Network (FFNN).  The localization of the iris is carried out using two methods namely Circular Boundary Detector (CBD) and Circular Hough Transform (CHT). The iris is segmented based on the iridology chart and unwrapped into polar form using Daugman’s Rubber Sheet Model.  The vagina and pelvis regions are cropped into pixel size of 40x7 for feature extraction using Principal component Analysis (PCA) and classified using FFNN.  In the experiments, 15 pelvis and 20 vagina regions are used for classification. The best result obtained gives overall correct identification from localization using CBD and CHT of about 67% and 81% respectively.  From the experiments, it is observed that vagina and pelvis regions are able to be identified even though the results obtained are not 100% accurate.
THE EXPLORATIONS IN DEFINING MOTORCYCLING FATIGUE: A PILOT STUDY
Authors: Mohd Talib Muhammad Fauzi , Nor Ma’arof Muhammad Izzat , Rashid Helmi , Ahmad Ismail Nasiruddin , Wan Fauzi Wan Muhammad Syahmi , Omar Abdul Rahman , Jaafar Roseleena
Published: October 2015

A renowned motorcycling instructor noted that human error is the main reason for motorcycling road tragedies. Indeed, there are various reasons that could be held responsible in leading towards human error. Even so, it is strongly emphasized that there is a link between motorcycle road accidents with the cases of human error due to motorcycling fatigue. The aim of this study was to explore the physical, physiological and psychological symptoms experienced by motorcyclists during prolonged motorcycling and its relation with motorcycling fatigue. This study assessed motorcycling fatigue generally, without specifying in a single type of fatigue resulting from prolonged motorcycling activity. Literature assessment, real world riding assessment, working posture hazard assessment and a survey study were selected as the research methods for this study. Results showed that collectively, all the physical, physiological and psychological aspects of the motorcyclist could be a variable in leading towards motorcycling fatigue. Nevertheless, all of these variables would only lead to two final outcomes which are: (i) overall decrement in motorcycling performance, and (ii) sleepiness. Both of these outcomes could occur independently or dependently – dependent on individual motorcyclist and the responsible variables that is affecting the particular motorcyclist. In short, motorcycling fatigue could not be simply defined with one single definition. Therefore, it is best to view motorcycling fatigue in various perspectives (physical, physiological and psychological perspectives) of motorcycle ergonomics. Motorcycling fatigue is almost inevitable, thus, further research is warranted in order to gain more accurate information and better understanding on motorcycling fatigue.
THE RELATIONSHIP BETWEEN STREET NETWORK MORPHOLOGY AND PERCENTAGE OF DAILY TRIPS ON FOOT AND BY BICYCLE AT THE CITY-LEVEL
Authors: Asadi-Shekari Zohreh , Moeinaddini Mehdi , Sultan Zahid , Shah Muhammad Zaly , Hamzah Amran
Published: October 2015

There are various factors that affect walking and cycling in urban areas, such as density, diversity and design, but there have been few studies that examine the relationship between urban morphology factors such as street network and green travel modes (e.g., walking and cycling) at the city-level (macro-level). Thus, this paper focuses on this relationship by introducing street network morphology factors, such as blocks per area, nodes per blocks and nodes per area. The street network in this study includes interconnecting lines and points that present streets, roads, motorways, intersections and blocks. The percentage of daily trips on foot and by bicycle data that represents walking and cycling are collected from the International Association of Public Transport’s (UITP) database. The blocks per area, nodes per area and the nodes per blocks are estimated by modifying and analyzing Open Street Maps (OSM). The data that are used in this study are from 30 cities in different parts of the world. The strength of the relationship in this study was found using the Pearson correlation coefficient. The results show that increase in daily trips on foot and by bicycle is correlated with increasing number of blocks per area and number of nodes per area while daily trips on foot and by bicycle has negative relationship with number of nodes per blocks. Because the urban street network is the result of macro-scale planning decisions, considering the relationship between street network morphology and travel behavior can lead to better planning decisions.
AN ALTERNATIVE METHOD OF ESTIMATING SPACE-MEAN SPEED
Authors: Muhamad Nor Nur Syahriza , Che Puan Othman , Mashros Nordiana
Published: October 2015

Average travelling speed usually applied in the traffic analysis as required in the fundamental traffic model. As one type of speed under the space-mean speed, most of the researchers have derived the equation to estimate the space-mean speed. There are a few factors that influence the speed changes along the segment. The fluctuate speed along the segment give an idea to average the spot mean speed from at least two points in order to estimate the space-mean speed. This paper explores an alternative method on how to convert the time-mean speed to space-mean speed that can represent the actual operating speed along segment using the average technique. A total of 18 data sets of time-mean speed and space-mean speed in six segments of uninterrupted two-lane single carriageway road were collected using automatic traffic counter and moving car observer, respectively. Two sets of automatic traffic counter were installed along the segment to record the spot speed and then converted to the time-mean speed, while the moving car observer were conducted concurrently to get the space-mean speed. The data sets were analysed using linear regression analysis. The results of summary of model show a strong relationship with coefficient of determination, R2=0.808, while ANOVA test results show the coefficient of constant and time-mean speed is not zero with p-value is less than 0.05 at confident level of 95%. The error obtained from this alternative equation are lesser than the established equation and it recommends that the alternative equation is acceptable.
DIFFERENCE IN THE BEHAVIOR OF RIGHT-TURNING VEHICLES AND THEIR EFFECT ON SAFETY AT UNSIGNALIZED INTERSECTIONS IN MALAYSIA
Authors: Ahmed Ashar , Mohd Sadullah Ahmad Farhan , Yahya Ahmad Shukri
Published: October 2015

Intersections are more prone to accidents as compared to straight road segments and vehicles that make right-turning maneuver are the ones which are more likely to be involved in an angle collision. Therefore, this study investigates their behavior at unsignalized intersections in Malaysia. The aim of this paper is to evaluate the compliance with the stop rule, use of turning indicator and right-turning behavior of minor road vehicles. All the behavioral observations were made with respect to two vehicle types which were ‘motorcycles’ and ‘others’. Descriptive analysis was presented and χ²-test was performed to investigate the association between the variables. It was found that most motorcyclists in Malaysia do not abide by the stopping rule at the intersection before making a right-turn. Moreover they seldom use their turning indicators and tend to make the indigenous ‘Weaving Merging Right-Turn’ (WMRT) more often as compared to other vehicles. Not complying with the stopping rule and keeping the indicator switched off while making a right-turn was found to be hazardous and resulted in the decrease in the safety of intersection and increase in the risk of accident. However, WMRT was found to be a safer maneuver as compared to the conventional right-turn. For vehicles other than motorcycles, the analysis concluded the same results. It is recommended that the methodology proposed in this research should be extended to other studies with a larger sample size.
TRAVEL BEHAVIOUR MODIFICATION TECHNIQUE – A FRAMEWORK FOR AWARENESS ON CARBON FOOTPRINT TOWARDS ADOLESCENTS IN DEVELOPING COUNTRY
Authors: Abdul Sukor Nur Sabahiah , Basri Nur Khairiyah , Hassan Sitti Asmah
Published: October 2015

Travel behaviour modification (TBM) techniques have been successfully implemented in many developed countries to reduce the negative impact of motorization and to increase the usage of more sustainable modes of transport. However, very little has been reported with regard to their effectiveness in developing countries. This paper emphasizes the framework of TBM techniques that might be implemented in developing countries by focusing on secondary school students as the main respondents. The recruited students were divided into four groups based on the assigned intervention approaches such as a control group (Group 1), journey planning group (Group 2), incentive group (Group 3), and journey planning with incentive group (Group 4). The main instruments for this study were travel diaries that were used to record the students’ daily travel activities and individual carbon footprint. The questionnaire survey was used to measure the pro-environmental awareness of the students. A few hypotheses in relation to the experiment on TBM techniques were also highlighted in this paper.
LABORATORY EVALUATION ON THE EFFECT OF CLOGGING ON PERMEABILITY OF POROUS ASPHALT MIXTURES
Authors: Abdul Hassan Norhidayah , Mohamed Abdullah Nor Asniza , Mohd Shukry Nurul Athma , Mahmud Mohd Zul Hanif , Mohd Yunus Nur Zurairahetty , Putrajaya Ramadhansyah , Hainin Mohd Rosli , Yaacob Haryati
Published: October 2015

Porous asphalt mixture is one of the alternative solutions to increase pervious surface area due to urbanization. The uniqueness of porous asphalt surface textures and internal structures allows the mixture to become a temporary storm-water retention and capable to channel excessive storm water. However, one of the major problems that affect the performance of porous asphalt mixtures is the clogging. Therefore, this study aims to determine the effect of clogging towards the permeability of porous asphalt. A total of 30 gyratory compacted samples were fabricated according to aggregate gradation recommended by Malaysia Public Works Department. The clogging materials were collected from two different location, residential area and major highway. The composition and characteristics of the clogging materials were investigated using Plastic Limit, Liquid Limit and Scanning Electron Microscope (SEM). The permeability test was conducted to investigate the permeability rate of the compacted samples based on different clogging material types, clogging concentrations and clogging cycles. In addition, the compacted samples were scanned using X-ray Computed Tomography to obtain the air voids distribution throughout the samples for comparison. It was found that higher concentration of clogging materials and clogging cycles reduced the rate of permeability. Clogging material collected from residential area has higher tendency to clog the void spaces compared to the one obtained from highway.
APPLICATION OF NANOTECHNOLOGY IN ASPHALT BINDER: A CONSPECTUS AND OVERVIEW
Authors: Wan Azahar Wan Nur Aifa , Bujang Mastura , Putra Jaya Ramadhansyah , Hainin Mohd. Rosli , A. Aziz Md. Maniruzzaman , Ngadi Norzita
Published: October 2015

Nowadays, the nanotechnology is widely applied in pavement engineering in order to improve the properties of materials and their performance. Nanotechnology can be considered as the measurement on nanometer scale that affects the material used in pavement due to its unique characteristic. Therefore, this new technology might indirectly solve the current pavement construction problems. The application of nanotechnology in enhancing the performance of fresh bitumen in term of the longevity and durability has been proven by a lot of previous studies and researches. Literatures have been reviewed and summarized critically to give an overview about the role of nanotechnology in improving pavement material properties. There are some concerns in the application of nanotechnology that needs to be addressed regarding to the safeties of these nano-materials in term of human health.
STRENGTH OF POROUS CONCRETE PAVEMENT AT DIFFERENT CURING METHODS
Authors: Mohd Yusak Mohd Ibrahim , Putra Jaya Ramadhansyah , Hainin Mohd Rosli , Ismail Che Ros , Wan Ibrahim Mohd Haziman
Published: October 2015

Porous concrete pavement has been used in some countries as a solution to environmental problems. Contrary to conventional concrete pavement, there is still lack of knowledge in some areas of production and performance of porous concrete pavement. One of the issue concern is curing conditions. These greatly affect the performance of porous concrete pavement. This paper elaborates the experimental results examining the influence of curing method and makes a comparison between five different curing methods on the strength of porous concrete pavement specimens. The properties analyzed include compressive strength, tensile splitting strength and flexural strength. The experimental results indicate that the different curing methods give a different effect to concrete strength. Based on the results obtained in this experiment, curing method by using polyethylene bag promise a good result and better performance to porous concrete pavement specimen strength.
FEASIBILITY ANALYSIS OF 2D-SLAM USING COMBINATION OF KINECT AND LASER SCANNER
Authors: Ali Yeon Ahmad Shakaff , Kamarudin Kamarulzaman , Visvanathan Retnam , Mamduh Syed Muhammad , Kamarudin Latifah Munirah , Zakaria Ammar , Md Shakaff Ali Yeon
Published: October 2015

Both laser scanner and Kinect has been widely used in robotic application for simultaneous localization and mapping (SLAM). However, each sensor has its own limitations. For example, Kinect does not have a wide range field of view and laser scanner could not detect obstacles beyond its scanning plane. The paper proposes a method to combine the data from Kinect and laser scanner to perform a 2D-SLAM. The sensors will be mounted in different types of configurations; both facing forward and facing in opposite directions. This system is able to detect complex surrounding features for better mapping and obstacle avoidance.
VIBRATION ISOLATION SYSTEM WITH ACTIVE STIFFNESS CONTROL
Authors: Ab. Rahim Muhajir , Abdul Majid Mohd Shukry , Abd Halim Mohamad Arinal
Published: October 2015

This paper presents the dynamic analysis of a linear isolator under active stiffness control. Firstly, the literature review on the active stiffness and the concept of skyhook spring are presented. Then, based on the theoretical equation govern the isolation system model, the effect of active stiffness control in the absolute motion transmissibility performance is studied. In addition, the force response of the isolation system under active stiffness control is also examined to highlight its benefits in improving the isolation system performance.
Z-SOURCE NEUTRAL POINT CLAMPED INVERTER FED MOTOR DRIVE
Authors: Karunamoorthy B. , Somasundareswari D.
Published: October 2015

Z-source inverter is a recently invented new power conversion concept mainly developed for fuel vehicular applications by advantageously utilizing the shoot through states to boost the DC-bus voltage. The impedance network contains two inductors and three diodes and is connected in between the DC source and inverter bridge. This shoot through state provides the unique buck-boost feature to the DC-link voltage and hence the AC output voltage of the inverter. By varying the boost factor and modulation index, the output AC voltage can be maintained at any value between zero and infinity regardless of DC voltage giving a wide range of voltage. Thus Z-source inverter overcomes the conceptual and theoretical barriers and limitations of the traditional inverters and provides high efficiency single stage structure for buck and boost operation. Previous publications have shown speed control of BLDC motor by controlling the DC link voltage of voltage source inverter using bridgeless buck boost converter. This paper presents the speed control of BLDC motor by controlling the shoot through states of Z-source neutral point clamped inverter using a space vector modulation technique which possess advantage of reduced harmonics with boosted output voltage. The proposed technique is demonstrated in simulation by using MATLAB software.
ANALYSIS ON ATTITUDE POSITION OF EARTH CENTERED INERTIAL (ECI) BASED ON RAZAKSAT DATA
Authors: Hasan Mohd Zamri , Yaacob Sazali , Ahmed Amran , Hamzah Nor Hazadura , Yaakob Shamshul Bahar , Idris Muhd Hafizi , Md Said Md Azlin
Published: October 2015

Attitude determination system (ADS) is a process to control the orientation of satellite to make sure that the orientation of satellite is relative to inertial reference frame such as Earth. Earth Centered Inertial (ECI) is one of reference frame for satellite that determines the attitude in three dimensional spacecraft. Since RazakSAT orbits on earth, ECI coordinate system will be used for satellite relative to earth rotation. This paper is about the analysis on attitude position of ECI and velocity at X, Y and Z axis based on RazakSAT data. Satellite Tools Kit (STK) is used to estimate the attitude and velocity based on Two Line Elements (TLE) of RazakSAT. The result is compared with RazakSAT measurement data to observe the accuracy of estimation by using STK.
AN INTELLIGENT NETWORK INTRUSION DETECTION USING DATA MINING TECHNIQUES
Authors: Mohd Shukran Mohd Afizi , Maskat Kamaruzaman
Published: October 2015

Network Intrusion Detection is to detect malicious attacks to the networks for different uses from military to enterprise. Currently available approaches either rely on the known network attacks or have high proportion of normal network traffics that were erroneously reported as anomalous traffics. The aim of this paper is to develop an efficient algorithm for intrusion detection without prior knowledge of network attacks. Uniquely, our approach will integrate a newly developed data mining technique for data feature classification with techniques commonly used for human detection. The key idea is to achieve on-line and automated learning of new attacks for precise and real-time intrusion detection.
MOTORCYCLISTS VS CAR DRIVERS: QUANTIFYING THE MAGNITUDE OF VEHICULAR DISCOMFORTS EXPERIENCED BETWEEN OPERATING A MOTORCYCLE AND A CAR
Authors: Mohd Said Mohamad Kharmizi , Nor Ma’arof Muhammad Izzat , Rashid Helmi , Ahmad Ismail Nasiruddin , Wan Fauzi Wan Muhammad Syahmi , Omar Abdul Rahman , Jaafar Roseleena
Published: October 2015

Vehicular discomforts are a type discomforts experienced by a human operator upon operating a vehicle. This type of discomfort could prevail both physically and physiologically. Generally, it could be said that vehicular discomfort is almost inevitable for all vehicles. Even so, from the preliminary studies, it was found that it is a norm for the Malaysian public to have a preconception that a motorcycle possessed a higher degree of vehicular discomfort that as oppose to a car. Hence, this study was made in order to test the validity of this cognitive linkage made by the public. The aim of this research was to quantify the magnitude of differences between the vehicular discomfort experienced between operating a motorcycle and a car. In addition, the sources of vehicular discomfort of these two modes of transportation were also identified. The methods used for this study were working posture assessment and survey studies (consisting of a questionnaire study and semi-structured interviews). From the selected research methodology, it was found that both types of vehicles showed an almost similar vehicular discomforts patterns. Even so, the sources of vehicular discomfort presented by these two types of vehicles are unique. By identifying the sources of vehicular discomfort given by these two types of vehicles, further ergonomics improvements could be implemented and more in depth research could be performed.
THE EFFECT OF LIQUID SUCTION HEAT EXCHANGER SUB-COOLER ON PERFORMANCE OF A FREEZER USING R404A AS WORKING FLUID
Authors: Nuriyadi Muhammad , Sumeru Sumeru , Nasution Henry
Published: October 2015

This study presents the effect of liquid-suction heat exchangers (LSHX) sub-cooler in a freezer. The LSHX sub-cooler is a method to increase the cooling capacity of the evaporator by lowering temperature at the condenser outlet. The decrease in temperature of the condenser outlet will cause a decrease in the quality refrigerant entering the evaporator. The lower the quality of the refrigerant entering the evaporator, the higher the cooling capacity produced by the evaporator. The LSHX sub-cooler utilizes a heat exchanger to transfer heat from the outlet of the condenser (liquid line) to the suction of the compressor. In the present study, three different LSHX sub-coolers in the freezer with cabin temperature settings of 0, -10 and -20oC were investigated. The results showed that the lowest and the highest of effectiveness of the heat exchanger were 0.28 and 0.58, respectively. The experimental results also showed that EER reduction is occurred at the cabin temperature setting of 0oC and -10oC, whereas the EER improvements were always occurred at the cabin temperature settings of -20oC.
EFFECT OF FIBRE TREATMENT ON LONGITUDINAL AND TRANSVERSE TENSILE PROPERTIES OF UNIDIRECTIONAL KENAF COMPOSITE
Authors: Manap Norhashidah , Jumahat Aidah , Sapiai Napisah
Published: October 2015

Kenaf fibre has become one of the best candidates to be used as reinforcement material in polymer composite. However, the adhesion between natural fibre and polymer is weak due to different polarity of natural fibre and hydrophobic polymer. This affects the properties of the composite. One of the method to overcome this compatibility issue is by treating the fibre using sodium hydroxide (NaOH). This study is aimed to evaluate the effect of NaOH treatment on longitudinal and transverse tensile properties of kenaf composites using three different concentration (3, 5, and 7 wt. % NaOH). The kenaf composite test specimens were prepared using filament winding and vacuum bagging techniques. The 0o and 90o tensile tests were conducted in accordance to ASTM standard D3039 in order to obtain longitudinal and transverse tensile properties of treated and untreated kenaf composites. The fracture surfaces of the specimens were observed using scanning electron microscope in order to identify fracture mechanisms involved during tension. NaOH treatment on kenaf fibre resulted in a significant improvement in longitudinal tensile modulus, strength and failure strain. This also indicates an improvement in toughness property as this can be observed through a larger area under graph of tensile stress-strain curve. The SEM micrographs showed that the interfacial adhesion between kenaf fibre and epoxy matrix was improved when the kenaf fibre was treated using NaOH. Therefore, NaOH treatment give positive effects on longitudinal and transverse tensile properties of kenaf composites. Kenaf composite treated with 7wt% NaOH showed the highest tensile strength for both longitudinal and transverse fibre directions.
FEEDSTOCK FLOW CHARACTERIZATION AND PROCESSING OF POROUS NITI BY METAL INJECTION MOULDING (MIM)
Authors: Ismail Muhammad Hussain , Mohamad Nor Nor Hafiez , Davies Hywel A. , Todd Iain
Published: October 2015

Porous NiTi alloy with a nearly three-dimensionally interconnected pore structure has been successfully fabricated by a transient liquid phase sintering following the metal injection moulding (MIM) process, using a mixture of Ni and Ti elemental powders. The elemental Ni and Ti powders mixture was mixed with a binder system, comprised mainly polyethylene-glycol (PEG) in an alternative technique using a speed mixer, principally incorporating a dual asymmetric centrifuge (DAC). The powder-binder mixture was then characterized using a capillary rheometer at various temperatures and shear rates. It was found that the feedstock exhibited pseudo-plastic behaviour, which is favourable for the MIM process. A temperature range of 120oC - 130oC was considered as the optimum operating condition for the injection moulding processing. The parts were moulded into cylindrical shapes, leached in warm water (60oC for 10 hours), thermally debound in argon and subsequently sintered in a vacuum furnace at four different temperatures ranging from 950oC to 1250oC.  All samples underwent expansion in both diameter and height after water leaching and sintering.  The XRD results showed that increasing the sintering temperature resulted in a major fraction of the B2 NiTi phase due to phase homogenization and subsequently decreased the amount of secondary phases such as NiTi2 and Ni3Ti. Besides that, the formation of the transient liquid phase during sintering enabled major fraction of pores to be developed with porosity and average size of 39 - 45% and 100 - 120 μm, respectively. The porous parts produced have a great potential to be used as an implant in biomedical applications.
Pipeline Corrosion Growth Modeling for In-Line Inspection Data Using a Population-Based Approach
Authors: Dann Markus R. , Maes Marc A. , Salama Mamdouh M.
Published: October 2015

To manage the integrity of corroded pipelines reliable estimates of the current and future corrosion growth process are required. They are often obtained from in-line inspection data by matching defects from two or more inspections and determining corrosion growth rates from the observed growth paths. In practice only a (small) subset of the observed defects are often reliably matched and used in the subsequent corrosion growth analysis. The information from the remaining unmatched defects on the corrosion growth process are typically ignored. Hence, all decisions that depend on the corrosion growth process such as maintenance and repair requirements and re-inspection intervals, are based on the information obtained from the (small) set of matched defects rather than all observed corrosion anomalies.

A new probabilistic approach for estimating corrosion growth from in-line inspection data is introduced. It does not depend on defect matching and the associated defect matching uncertainties. The reported defects of an inspection are considered from a population perspective and the corrosion growth is determined from two or more defect populations. The distribution of the reported defect sizes is transformed into the distribution of the actual defect sizes by adjusting it for detectability, false calls, and sizing uncertainties. The obtained distribution is then used to determine the parameters of the assumed gamma-distributed corrosion growth process in order to forecast future metal loss in the pipeline. As defect matching is not required all reported corrosion defects are used in the probabilistic analysis rather than the truncated set of matched defects. A numerical example is provided where two in-line inspections are analyzed.
Comparison of Three Different TLPs for Wind Turbines by Tank Tests and Calculated Results
Authors: Adam F. , Myland T. , Dahlhaus F. , Großmann J.
Published: October 2015

This paper will give a short overview of the path of development of the so called GICON® - Tension Leg Platform (TLP) for offshore wind turbines. The main part of the paper will provide a summary as well as insights from three different model basin tests. Furthermore, the comparison of a truss like structure (first concept) with a shell type structure (third concept) deduced from the measured results and also by comparison of the natural frequencies will be presented. Both structures were tested in wave tanks in a scale of 1:25. The results also include a focus on the overall dynamic behavior of the structure. In addition to the two 1:25 models, a 1:37 model was also tested at MARIN, utilizing the MARIN stock wind turbine. This model is also included in the comparison. Therefore the different scales are considered but the comparison is presented exclusively for wave loads as only the 1:37 model was tested under wind and wave conditions.
Current and Future Tendency of Monitoring Technology for Integrity Assessment and Life Extension of the Hull Structure of Floating Production, Storage and Offloading (FPSO) Vessel
Authors: Guan Shan
Published: October 2015

This paper critically reviewed commercially available hull stress monitoring systems (HSM) and summarized notations for vessels with hull stress monitoring systems from major classification societies. The authors recommended that, for every FPSO vessel, at least one HSM should be equipped in compliance with regulation from the International Maritime Organization. Additionally, sixteen types of sensing technologies were identified for monitoring of FPSO Vessel. Depending on the technology matureness and readiness for application in marine structures, they were categorized into three groups: Proven, Un-Proven and State-of-the-art technology. Furthermore, challenges associated with FPSO hull monitoring including Sensor Systems, Communication and Data Analysis techniques were examined. It is concluded that multiple sensing technologies should be systematically combined to provide more accurate information. Based on these discussions, a feasible solution that integrates proper wireless sensor network technology and Bayesian Network modeling was proposed as the future direction of FPSO hull monitoring system.
The Thermal Expansion Analysis for Submarine Pipe-in-Pipe Based on Shear Lag Theory
Authors: Liu Xiaoxia , Jia Xu , Jia Lusheng , Ni Kankan
Published: October 2015

The thermal expansion analysis is important in submarine pipeline design and research. A new thermal expansion analysis method of submarine pipe-in-pipe is proposed in this paper based on the shear lag theory. The axial force distribution and the thermal expansion displacement of submarine pipe-in-pipe can be calculated by this method. The analysis method is simple and convenient but with detailed results. It can be used for the thermal expansion analysis of submarine pipe-in-pipe.
Validation of Hydrodynamic Load Models Using CFD for the OC4-DeepCwind Semisubmersible
Authors: Benitz Maija A. , Schmidt David P. , Lackner Matthew A. , Stewart Gordon M. , Jonkman Jason , Robertson Amy
Published: October 2015

Computational fluid dynamics (CFD) simulations were carried out on the OC4-DeepCwind semisubmersible to obtain a better understanding of how to set hydrodynamic coefficients for the structure when using an engineering tool such as FAST to model the system. This study focussed on the drag behavior and the effects of the free surface, free ends and multimember arrangement of the semisubmersible structure. These effects are investigated through code-to-code comparisons and flow visualizations. The implications on mean load predictions from engineering tools are addressed. This study suggests that a variety of geometric factors should be considered when selecting drag coefficients. Furthermore, CFD simulations demonstrate large time-varying loads caused by vortex shedding that FAST’s hydrodynamic module, HydroDyn, does not model. The implications of these oscillatory loads on the fatigue life needs to be addressed.
Study of an Alternative Material for the Manufacture of Subsea Umbilical Hydraulic Hoses
Authors: Pasqualino Ilson , da Costa Marysilvia , Drumond Geovana
Published: October 2015

Hydraulic hoses are components of subsea umbilicals that are responsible for Xmas tree gate valves actuation. These hoses are susceptible to collapse by external pressure and, since they are fabricated of rigid polymers, this failure can lead to strain concentration at specific points across the circumference, leading to rupture due to high internal pressure. The objective of this work is to study an alternative material to be employed in the manufacture of the hydraulic hose liner that can support the internal pressure (associated to the aramid layer) after an eventual collapse, and that have no chemical interaction with the hydraulic fluid used. This study is based on the comparison between the material currently used (Polyamide 11) and a fluorinated elastomer, Viton®. To compare the mechanical behavior of both materials, uniaxial tensile tests as well as nonlinear finite elements models were performed. The results obtained by finite element analysis showed that both, Polyamide 11 and Viton®, did not fail under external pressure. However, Polyamide 11 concentrates high plastic deformations after collapse that can lead to located hose rupture under internal pressure. For Viton®, it was found that the material concentrates deformations during collapse but these deformations are recovered when internal pressure is applied. Considering that the external aramid layer is responsible to withstand the internal pressure in both cases, Viton® can successfully replace Polyamide 11 for this application.
Advanced Simulations = Better Results. Really?
Authors: Bertram Volker , Zorn Tobias , Rognebakke Olav
Published: October 2015

This paper looks at selected applications of advanced hydrodynamic simulations in the offshore oil & gas industry. Progress in computational techniques and hardware has opened the door to more advanced simulations. But do more advanced field equations really lead to better results? Or should we employ proven potential-flow codes along with the engineering insight and experience, as they are cheaper and faster? The answer is not trivial and needs to be found and justified for each application. But the paper shows applications of viscous flow simulations (RANSE) where potential flow simulations ruled supreme. Traditional arguments concerning computational time are eroded by massive parallel computation. The applications shown concern: second-order forces in waves, formal optimization of offshore structures, impact loads, short-crested irregular sea in RANSE simulations and vortex-induced vibration analyses.
Maximum Crest Heights Over an Area: Laboratory Measurements Compared to Theory
Authors: Forristall George Z.
Published: October 2015

Platform decks cover a reasonably large area compared to the size of a wave crest. Ocean waves are dispersive and directionally spread. As they propagate, their crest heights change. A platform deck samples those waves at many different locations. The maximum crest height over the area of a deck during a storm will naturally be greater than the maximum at a single point. The principle is clear but measurements are needed to confirm quantitative theoretical predictions. Such measurements were made in Marin wave basins using an array of 100 wave probes. At prototype scale, they covered an area of 100 by 100 m. Random directionally spread waves with prototype significant wave heights from 12 to 15 m and peak periods from 12 to 15 sec were generated and run through the array. Measurements were also made with pressure gauges mounted underneath a model platform deck placed at 11.5 and 13.0 m above still water level. Numerical simulations are used to find the maximum linear crest height expected over these areas. The second order enhancement of crest is accounted for by factoring the Gaussian maximum. Empirical fits to the simulations were found that can be used for most practical problems.
Analysis of Iceberg, Pack Ice, and Ocean Current Dynamics Offshore Newfoundland and Labrador From Satellite-Tracked Buoys During the 2014 Ice Season
Authors: Turnbull Ian D. , Taylor Rocky S. , Sarracino Robert , Slaney Aaron , Roche Laura C.
Published: October 2015

Shipping operations along the coasts of Newfoundland and Labrador associated with Grand Banks oil and gas production, as well as mining operations in Labrador, may be exposed to potentially hazardous ice conditions. Possible future development of oil and gas reserves offshore Labrador will also be exposed to risk associated with iceberg and pack ice conditions. Improved understanding of the characteristics of ice dynamics and metocean forcing mechanisms behind them will lead to more efficient operational planning and safer operations. Accordingly, CARD has initiated a long-term project to collect and analyze data on the pack ice and iceberg dynamics in these regions. This paper presents an analysis of the drift of pack ice features and two icebergs tagged with satellite-tracked buoys during April-August and July-August 2014, and characterizes their drift in the context of the winds and currents driving their dynamics.
A Comparison of Frequency and Time Domain Fatigue Damage Using the Battelle Structural Stress Methodology
Authors: Healy Brian E.
Published: October 2015

A frequency domain fatigue analysis using the Battelle structural stress methodology has been performed on a shear plate connection detail typical of a representative cell spar in North Sea service. In parallel, time domain cycle counting of the Battelle structural stress ranges has been performed on the same connection detail. The frequency and time domain fatigue damage computed at various locations is reported and compared. Recommendations regarding the application of the Battelle method to wide-banded spectral fatigue problems are provided.
Effects of Underwater Explosion on Pipeline Integrity
Authors: Bartolini Lorenzo Maria , Marchionni Lorenzo , Molinari Caterina , Parrella Antonio
Published: October 2015

Unexploded charges e.g. mines, bombs, torpedoes, etc... are rarely identified at a very early stage of reconnaissance surveys for pipeline route corridors. These ordnances are found during detailed pre-engineering or pre-lay surveys and, sometimes and not surprisingly, during the ordinary surveys performed on the pipeline in service. UXOs represent a hazard for the pipeline as well as for the assets and people involved in the construction phase. An appropriate mitigation plan in areas potentially affected is generally performed, including ordnance removal or mined-area clearance. Large diameter long offshore trunk lines crossing different territorial waters are often exposed to this kind of hazard. As such, pipeline construction and operation call for advanced numerical modelling as unique/valuable tool for providing a quantitative measure of the UXOs related risks.

In recent projects the understanding of the underwater explosion process and prediction of damages associated to specific weapon-target engagement are based on the outcome of engineering tools based on finite element modelling. The continuing development of multi-purpose and multi-physics finite element analyses codes facilitates their application, providing sharp and detailed insight into the complex subject of underwater explosive effect and the coupled response of nearby structures. The scope of the structural integrity assessment is to define the minimum distance to be guaranteed between the pipeline and unexploded ordnance to avoid any risk of pipeline damage, as a function of the quantity of explosive. The engineering task of the integrity assessment includes the definition of the relevant conditions for the pipeline whether buried or free spanning, the analysis of the interaction between the gas bubble and shock pressure waves and the cylindrical shape of the pipeline, both as a shell that collapse under a pressure wave and a pipe length that moves laterally and develops bending. The objective is to evaluate the minimum allowable distance of the ordnance from the pipeline, as a function of the explosive quantity and type.

In this paper, a series of real cases is presented in order to provide the most relevant parameters characterizing the integrity assessment under the applied load scenario from propagating shock waves. The propagation in water of shock pressure waves induced by the underwater explosion of a spherical charge is performed using finite element modelling, after model verification and validation with respect to the analytical and experimental formulations available in open literature. The outcome from finite element modelling is compared with findings from a simplified model based on modal analysis of the pipe shell – inward bulging and collapse of the pipe section and of the pipe beam – lateral displacement of the impacted stretch and bending at the crest of the buckle.