bluuebunny/crossref_metadata_2025 huggingface dataset:
Studying the Effect of Precipitation Hardening on 6061 Aluminum Alloy Weldments
Authors: Ahmad Tahir , Kamran Muhammad , Faizan Muhammad , Ahmad Rafiq , Ariwahjoedi Bamban , Hussain Faraz , Riaz Fahad
Published: December 2015

The high specific strength, ease of working, good weldability and the ability to be precipitation strengthening have increased the demand of aluminium alloys in aerospace and automobile industries. In this research the effect of artificial aging/precipitation hardening on mechanical properties and microstructures of 6061 aluminum alloy weldments produced using gas tungsten welding (TIG) was studied. The artificial aging of welded alloy was carried out at temperatures varying from 150°C to 170°C for different period of time. The Vickers hardness and tensile test were carried out to evaluate the response of material to heat treatment. The experimental work showed that the maximum hardness and tensile strength of 6061 aluminum welded samples was achieved when aged at 170°C (after solution treatment) for 2 and 10 hours. Scanning electron microstructure analysis revealed that after solution treatment, when the samples were aged at 150-170°C, the Mg2Si precipitates present in the grains grows in size and develop stress in the grain and resulted increment in hardness.
Assessing the Physical Properties of Cobalt Chromium Molybdenum (CoCrMo) Foams with Different Composition
Authors: Abdul Manaf Nur Suliani , Ahmad Sufizar , Ibrahim Rosdi
Published: December 2015

Replication or slurry dipping is a simple and popular method of producing porous and interconnected foams using a metallic slurry. The advantage of the network-like metal foams is it exhibits a natural bone-like structure which enables ingrowth of bone cells and blood vessels. The aim of the present study was to investigate the physical properties of Cobalt Chromium Molybdenum (CoCrMo) foams after sintering process using vacuum furnace. The CoCrMo slurry was prepared by using different composition of CoCrMo powder which was 50wt%, 55wt%, 60wt%, 65wt% and 70wt%. The CoCrMo slurry was produced by mixing CoCrMo powder with Polyethylene Glycol (PEG), Carboxyl Methyl Cellulose (CMC) and distilled water. Then, polymeric foam template was impregnated in CoCrMo slurry and dried at room temperature. Sintering was carried out in a high temperature vacuum furnace at 1300°C. The CoCrMo foam was characterized by using a Scanning Electron Microscopy (SEM) analysis. The physical properties of CoCrMo foam was analyzed by porosity and bulk density test that was Archimedes method. From the study it was expected that the composition of metallic slurry play important roles to produce a CoCrMo foam. The best composition that obtained in this experiment was 70wt%. The porosity and density value for 70wt% of composition were 20.3% and 2.63g/cm3. The higher composition of metallic slurry will decrease the density and will increase the porosity.
Micro-Hardness Study on AISI P20 Steel Using Taguchi Method
Authors: Biswas Chandan Kumar , Sethi Ritanjali , Gangopadhyay Soumya
Published: December 2015

A well-designed experimental were conducted with L18 Orthogonal Array (OA) based on the Taguchi method with input factors discharge current, pulse on time, lift time and flushing pressure. Micro hardness was measured and the mean of the observed values were plotted. The factors effecting the micro-hardness of the work-piece has been obtained. It is inferred that micro-hardness value increases with increase in discharge current and decreases with increase in Pulse on Time. The optimal condition for minimum hardness was found to be discharge current (Ip) = 2A, pulse on time (Ton) = 500μs, lift time (Tup)= 1.4 ms and flushing pressure (Fp)= 0.2 kgf/cm2.
Degradation of Compressor Blades of Gas Turbines in Coastal and Industrial Environment
Authors: Yunus Salmi Mohd , Sekari Saiful Adilin , Abdul Ghaffar Mohd Hafiz
Published: December 2015

Gas turbine compressor blades will age and degrade in their operation. There are a lot of factors that will contribute to the degradation mechanisms and its acceleration. These factors encompass the site location, the site conditions including the aspect of air quality, water washing practice, etc. A study undertaken by Materials Engineering Group of TNB Research Sdn Bhd on 2 units of gas turbine compressor those are located near to the sea around Peninsular of Malaysia, to determine the degradation mechanisms of the blades. All these gas turbine units are located in different industrial environment. The first gas turbine unit, so called GTA is located in coastal, petrochemicals production and crude oil refining environment. The second gas turbine unit, so called GTB, located in coastal and industrial environment. The surrounding industries of GTB including oil refinery, chemical, ship fabrication and etc. This paper reports the degradation type of those gas turbine units’ compressor blades with their contributing factors.
Surface pH Measurement during CO2 Corrosion by an IrOx pH Probe
Authors: Kakooei Saeid , Ismail Mokhtar Che , Ari-Wahjoedi Bambang
Published: December 2015

CO2corrosion comprises the majority of material damage, which leads to shutdown in petroleum industries. This phenomenon depends on parameters such as pH and temperature. Monitoring and recording these parameters help industries minimize waste in terms of time and financial resources. The insufficiency of tools for this purpose is noticeable. This study proposed an potentiometric IrO2–pH microelectrode design in conjuction with a Ag/AgCl refrence electrode for real-time corrosion monitoring that can be used in various industries. Electrodeposition approach was used in the fabrication of a pH sensor. Electrochemical experiments were conducted to characterize the IrO2–pH sensor as well as monitor the pH on a metal surface in conjunction with the fabrication of a pH microelectrode-designed system. Results show that the proposed pH sensor design can be used for real-time corrosion monitoring by surface pH measurement.
Dose Reassessment by Using PTTL Method in Ge-Doped SiO2 Optical Fiber Thermoluminescence Dosimetry
Authors: Zulkepely Nurul Najua , Mat Nawi Siti Nurasiah , Wahib Norfadira , Mohd Amin Yusoff , Md Nor Roslan , Maah Mohd Jamil , Bradley David Andrew
Published: December 2015

In this paper we report, the characteristics of PTTL after irradiation with 60Co gamma rays as a function UV light exposure wavelength, gamma irradiation dose, and UV light exposure time were determined for Ge-doped SiO2 optical fibers. The efficiency of dose reassessment for this fiber was compared to standard thermoluminescence detector, TLD100. Experiments show that the method works well with the UV lamp of 254 nm within region of doses between 3 to 50 Gy, but could be applied for higher and lower doses as well. The effect of exposure time of UV radiation on the PTTL signal was studied from 5 to 120 minutes to determine the highest sensitivity and the limit of the dose. The efficiency of dose reassessment with 10 Gy of gamma irradiation expose to UV light for 15 minutes relative to PTTL values of about 27.0% and 2.3% for Ge-doped SiO2 optical fiber and TLD100.
Optical and Color Properties of Green and Red Phosphor Mixtures Doped into Hybrid Sol-Gel Matrix to Generate White Light
Authors: Yusoff Nurul Huda , Shualdi Wedianti , Nik Abdul Aziz Nik Mohd Azmi , Wan Jaafar Wan Mohammed Nazrul
Published: December 2015

Eu (tta)3phen and Tb (4DBBA)3TPPO were synthesized as red and green phosphor for generating white light under the excitation of UV LED. The phosphor materials were doped into hybrid sol-gel (VTES:TEOS) matrix with different ratio of 1:8, 1:16, 1:25, 1:30, 1:40 and 1:50. The samples were fabricated as thick films by drop-casting and heat treated at 60°C overnight. Photoluminescence spectra were measured using spectrafluorometer system. Measurement of color properties such as color rendering index (CRI), color temperature and Commission Internationale de L’Eclairge coordinates were recorded by exciting the samples using a 380nm UV LED and focused the generated light into an integrating sphere. Based on the results, the mix ratio of 1:40 produce the nearest coordinate within the white color region with color temperature around 4100K to 4200K.
Lignin Effect on Tensile Properties of Biodegradable Urea-Crosslinked Starch in Aerobic Soil Microcosm
Authors: Majeed Zahid , Mansor Nurlidia , Man Zakaria
Published: December 2015

Lignin has proved its potential role as biodegradable filler for reinforcement of composite materials derived from renewable resources. Slow release fertilizer (SRF) based on starch was tested with different lignin weight percentages (5, 10, 15, 20 wt%) to analyze its effect on mechanical properties of non-biodegraded (NB) samples before and biodegraded (BD) samples after the incubation in the aerobic soil microcosm. In all NB samples, elongation at break (EB), young’s modulus (YM) and tensile strength (TS) was improved with increasing lignin from 5 to 20 wt%. However, in all BD samples, percent change in EB, YM was increased towards higher values as the lignin percentage increases. It was also observed a significant difference (pair t-test, p < 0.05) between each composition before and after biodegradation. In BD samples with 5-15 wt% lignin, percent change in mechanical properties was non-significant (pair t-test, p > 0.05). It was further noticed that percent change in mechanical properties was low in BD samples with lignin compared to the BD samples without lignin. From the present work, it is concluded that lignin strengthens the lignin-starch matrix in NB samples and it also reduced the impact of mechanical properties loss in BD samples.
Effect of Single and Bimetallic Ni, V and Mn Transition Metal Ion Doping on the Properties of Anatase/Brookite TiO2 Photocatalyst
Authors: Mohamed Islam Noor Zalikha , Kosslick Hendrik , Zainuddin Mat Tamizi , Zubir Zuhana Ahmad , Abdul Aziz Nazri Shamsul Azrolsani , Abdul Malek Mohd Zahid , Mohd Ezwan Mohamed Izat , Md Salleh Shahrul Nizam , Abdul Aziz Mohd Syaifurizwan
Published: December 2015

Titania with a mixture of anatase, rutile and brookite nanostructures have gained much attention lately due to their high photocatalytic activity. Pure titania (TiO2) with a mixture of anatase, rutile, brookite phase were synthesized by hydrothermal treatment using titanium isopropoxide (TTIP) and 1.0 M of urea. The titania were doped with 1wt% of single transition metal nickel (Ni), vanadium (V) and manganese (Mn) and 1 wt% bimetallic transition metal of Ni-V and Ni-Mn, respectively. Pure titania shows higher, 94 % degradation of ibuprofen (Ibp) as the presence of brookite phase in the structure. The band gap energy of titania was obtained using the Kubelka-Munk reflectance function decreased as doping a transition metallic dopant where the energy order are V<MN<Ni, respectively. Bimetallic dopant V and Mn contribute higher photocatalytic activities as decreasing band gap energy of Ni ion doping.
Synthesis of Ionic Liquid Polymer Incorporating Activated Carbon for Carbon Dioxide Capture and Separation
Authors: Mahmood Hamayoun , bin Ahmad Sayukhi Muhammad Hafiz Arif , Moniruzzaman Muhammad , Yusup Suzana
Published: December 2015

CO2 capture and separation by ionic liquid is one of the fastest growing branches in ionic liquid technology. The aim of this research was to synthesize the ionic liquid polymer incorporating activated carbon and investigating its performance for CO2 capture and separation. The ionic liquid monomers 1-vinyl-3-ethylimidazolium bromide, [veim][Br] and 1-vinyl-3-ethylimidazolium bis (trifluoromethyl-sulfonyl) imide, [veim][Tf2N] were first synthesized and then polymerized into ionic liquid polymers incorporating activated carbon. The purity of the [veim][Br] and [veim][Tf2N] was verified by 1H NMR, 13C NMR and Ion Chromatography. Both monomers were proved to be in high purity. The elemental composition of both polymer materials synthesized were examined using energy dispersive X-ray spectroscopy (EDX) and the morphology of the synthesized material was observed using field emission scanning electron microscopy (FESEM). The results revealed that activated carbon has been successfully incorporated into the lattice structure of polymer materials. The fabricated polymer materials would be expected to have higher CO2 capture capability as it combines both the absorption and adsorption mechanism for CO2 apprehension and sequestration.
Tensile and Fracture Toughness Properties of Coconut Spathe Fibre Reinforced Epoxy Composites: Effect of Chemical Treatments
Authors: Abdullah Abdul Hakim , Abdul Mutalib Faris Firdaus , Mat Muhd Faiz
Published: December 2015

Natural fibres are considered as a potential replacement for man-made fibers in composite materials because of their advantages over other established materials. However, serious problem of natural fibres is their strong polar character which creates incompatibility with most polymer matrices. In present investigation, the effect of alkaline, silane and combination of both treatments is investigated. Tensile properties and fracture toughness of coconut spathe fibre for untreated and treated were evaluated. Samples were fabricated by using the hand layup process. Result indicated that silane treatment has achieved a better performance for the tensile test while there is none improvement fracture toughness was displayed by silane or alkaline treatment as compared to untreated fibres. The alkaline treatment showed to be harmful for fracture toughness of the coconut spathe fibre since the improved interfacial adhesion impaired the main energy absorption mechanisms.
Keyword: Composites, Coconut Spathe Fibre, Alkaline and Silance Treatment
Capillary Force-Aided Gas Hydrate Growth in Shut-In Conditions
Authors: Divan Jega , Lal Bhajan , Sabil Khalik M. , Hammonds Paul
Published: December 2015

This paper presents a significant finding where a capillary force is observed for a gas hydrate growth under a 24-hours shut-in condition (static fluid) using a newly designed apparatus comprising six units of identical rocking cells within isochoric conditions. The gas hydrate growth (static condition) is compared to a gas hydrate formation under a rocking condition. Crystal growth with a simulated natural gas mixture at various time intervals is noted. The visual observations of nucleation and growth at a wetted surface are described. The obtained visual results suggest that capillary forces provide continuous mass-transfer of water towards gas hydrate growth, even within shut-in conditions.
Leaching and Kinetic Modeling of Malaysian Low Grade Manganese Ore in Sulfuric Acids
Authors: Ismail Suhaina , Hussin Hashim , Saiyid Hashim Syed Fuad , Abdullah Norazharuddin Shah
Published: December 2015

The leaching process of Malaysian low grade manganese ore (LGMO) using bamboo sawdust (BSD) as reducing agent in acidic medium (H2SO4) and the dissolution kinetics of this ore was investigated. Acid concentration, reaction temperature, and BSD loading were chosen as experimental parameters through application of response surface methodology (RSM). For analysis of the kinetic data in this study, the SCM with surface chemical reaction and diffusion through product layer, the mixed control modelled and also new variant SCM were evaluated. The reaction kinetics of this leaching process was determined, and it is observed that it fits the model of 1-23X-(1-X)23=kt with activation energy of 69.3kJ/mol. The reaction rate for LGMO leaching using BSD was found to be diffusion through product layer.
Advances in Evaluation of Surfactant Performances at High Temperature by Static Foam Tests
Authors: Mumtaz Mudassar , Tan Isa Mohd , Mushtaq Muhammad , Sagir Muhammad
Published: December 2015

—Foam stability and mobility reduction are the key parameters for foam assisted enhanced oil recovery. The harsh conditions such as high temperature, pressure and salinity present in an oil reservoir tend to destabilise the foam leading to poor sweep efficiency. Screening for the best performing foaming recipes has been performed to ascertain foam stability in the presence and absence of oil. Static foam test has been performed in order to study the foam stability and foam oil interactions at 90°C. Two anionic surfactants, alpha olefin sulphonate (AOS14-16) and methyl ester sulphonate (MES16-18) were mixed with betaine (foam booster) in different proportions to design the formulations. In addition to the ternary formulations, binary formulation involving surfactant and betaine were also evaluated for foam stability. For the study of oil effects on foaming performance of surfactant formulation, n-decane, diesel and Dulang crude oil are used. The recipes were evaluated by static foam tests to note the foam height and endurance time. It was found that the anionic surfactant played a major role in foam stability and the betaine was found less significant. However, the betaine alone was found effective for foaming and was poor for endurance time. While in mixture, the surfactant and betaine were found to interact strongly and a profound synergistic effect was noted. During oil interaction studies, the alkane type oils of low molecular weight become solubilised with surfactant molecule forming an emulsion and hence decimate the foam stability. However, higher alkanes with molecular chain more than ten carbon atoms (decane) stabilised the foam because of low solubilisation efficiency between surfactant and oil to form emulsions. The obtained results of the designed experiment have been analysed and discussed in detail to understand the contribution of individual component as well as their interactions with each other in order to stabilize foams.Keywords—Static Foam, Foam-Oil interactions, AOS, MES, Enhanced Oil Recovery
Absorbance Analysis of Escherichia coli (E. coli) Bacteria Suspension in Polydimethylsiloxane (PDMS)-Glass Based Microfluidic
Authors: Md Salih Nurulazirah , Hashim Uda , Nafarizal Nayan , Soon Chin Fhong , Sahdan Mohd Zainizan
Published: December 2015

The emerging of bacteria/cell culturing in biological/biomedical research and industry is in demand for low cost, fast, non-invasive, and reliable alternative/approach for evaluation and measurement. Microfluidic approach is one of the promising alternatives for replacing the expensive commercial cuvvete for bacteria/cell culture and suspension for optical measurement. This study demonstrates the integration of absorbance measurement with microfluidic platform forEscherichia coli(E. coli) bacteria suspension analysis. TheE. coliwas cultured and prepared for suspension medium which then transferred inside the PDMS-glass based microfluidic. Then, the absorbance measurement is carried out using UV-Visible spectrophotometer. We demonstrate this method by measuring absorption of light transmitted through microfluidic chambers within the visible light range (350nm - 750nm). From the result, it had indicates that the graph pattern and growth behavior ofE. colisuspension in microfluidic platform are reliable and comparable to commercial cuvvete reading. This finding
Effects of Board Density and Thickness on Properties of Laminated Floor Panel from Kenaf (Hibiscus cannabinus) High Density Fibreboard (KHDF)
Authors: Mohd Khairuddin Nurul Nadia , Ahmad Mansur , Mohd Ayob Nurul Atiqah
Published: December 2015

This paper investigated the effect of density and thickness on flexural strength and dimensional stability of laminated floor panel. The focus of this research is to acknowledge the suitability of Kenaf fibres as raw material for floor panel. The evaluated floor panel samples consist of high density fibreboard as a core of floor panel and resin impregnated paper as lamination. The core was made up from Kenaf (Hibiscus cannabinus) bast fibres that were used to fabricate dry-formed fibreboard at three different board densities (850, 960 and 1000 kg/mʒ) with the thickness of 8mm and 12mm for each board. Bending modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) and thickness swelling (TS) were measured for each panel in accordance to BS EN standard. The overall result showed increasing density and thickness increased were MOE, MOR, TS and WA. Density and thickness were significantly affecting all the panels’ properties except for MOR, TS and WA.
Mechanical Properties of High Loading Luffa acutangula Fiber with Cloisite 15A and Polypropylene
Authors: Umar Shaifudin Siti Nurai'syah , Kamarun Dzaraini , Seth Nur Hikamah , Engku Zawawi Engku Zaharah
Published: December 2015

Matured luffa fibers can be used as reinforcing fillers for polymers to produce industrial products. Frequently, these fibers are incorporated in thermoplastics and thermosets binders at low loadings (1 – 40) wt % of total composition. In this project, high loadings of luffa fiber (50 to 70 wt %) were incorporated with polypropylene (PP), coupling agent maleic anhydride grafted polypropylene (MAPP) and Cloisite 15A using extrusion for compounding. (C15A) at 5 wt % was added for reinforcement and to increase density of compounded materials for ease of processing during mixing. The compounded material was pelletized and the test pieces were prepared using compression moulding and shaped according to the standard. The effects of fiber loadings on the mechanical properties of the composites were determined.
Effect of Processing Method on Thermal Behavior in PLA/PEG Melt Blending
Authors: Hashim Norazlina , Retenam Kamala , Somderam Santhoshini , Yusoh Kamal
Published: December 2015

The dispersion of PEG acts as plasticizer in PLA blends were investigated using thermal analysis. The comparisons were made between two melt processing method, twin screw extruder and two-roll mills to study how it will affect theTg,TcandTmof blends in DSC analysis. The TGA behavior was also studied for two-roll mills processing method to confirm the effect of PEG loading in PLA on degradation and amount of residue left after analysis. In DSC analysis, it can be seen clearly, the PEG loading decreased the glass transition temperature in all blends compares to neat PLA. For twin screw extruder blending, the crystallization peak existed for some blend. It was difference for two-roll mills blends where the crystallization peak absent in all blends with PEG loading. The presence of PEG gave no significant variation on melting temperature peak for both processing method.
Effect of Molecular Weight on Morphological Structure of Electrospun PVA Nanofibre
Authors: Abdullah@Shukry Nur Athirah , Ahmad Sekak Khairunnadim , Ahmad Mohd Rozi
Published: December 2015

This work focuses on the preparation of electrospun Polyvinyl Alcohol (PVA) nanofibres of three different molecular weights. The electrospinning process parameters were varied in terms of the voltage and feed rate. Scanning Electron Microscopy technique was used to characterize the morphological structure of the electrospun PVA nanofibre. The results show that the average fibre diameter increased as the molecular weight of the polymer increased. The formation of beads occurs from the lowest molecular weight sample of 89K However, long, continuous and beaded-free fibres were obtained from the 125K and 205K polymer weight PVA. The results also suggest that higher spinning voltage and feed rate produce larger fibre diameter, respectively.Keywords : Polyvinyl Alcohol, nanofibres, molecular weight, electrospinningCorresponding Author:Khairunnadim Ahmad Sekak, Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan.Email: nadim821@salam.uitm.edu.my
Extraction and Characterization of Galactomannan from Seeds of Leucaena leucocephala
Authors: Shirajuddin Shazlinda , Kamarun Dzaraini , Ismail Nahlah Elkudssiah , Abdul Wahab Mohd Shahezwan , Li Abdul Rashid , Rahim Nurnadiah
Published: December 2015

Galactomannan is a biopolymer polysaccharides mostly obtained from Leguminosae plant have shown an interesting capability as drug carrier. In this study, galactomannan from the seeds ofLeucaenaleucocephalaknown locally as ‘petai belalang’ was obtained by water extraction. The galactomannan was characterized structurally by nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FTIR). Highly molecular weight of galactomannan, > 2.56 x 106Da, was successfully extracted from the plant. Total carbohydrate content of this polysaccharides is 74.84% and composition of galactose and mannose have been confirm by high performance liquid chromatography (HPLC) which is 36.67% and 38.17% respectively. M/G ratio was determined as 1:1. Hence, galactomannan has been successfully extracted from the seeds ofLeucaenaleucocephala.
Design Method of Kitting System in Flexible Assembly Line Based Manufacturing for Mass Customisation Adaptation
Authors: Wan Saidin Wan Ahmad Najmuddin , Musa Mohd Azam , Kasim Nazrul Idzham , Norhidayah M.H. , Ramli Siti Solehah
Published: December 2015

This paper describes the design method of kitting systems for variant engine assembly, which contribute to performance of parts assembly flexibility and efficiency. The need for efficient material handling part delivery is higher especially in automotive industry due to extensive product customisation and the small area to keep all the necessary parts at the assembly line. The paper focuses on the suitability of design KS in the essence of reliability, safety and ergonomics of workers. Relatively, the design consider the flexibility of the kit process in engine assembly parts with regard to performance measurement resulting in overall efficiency and accuracy of production line. Associated with Lean approach, KS provide an essential outcome required that avert a non value adding activities to take place in assembly line. It is believed that the findings of this study will provide an optimum efficiency of part feeding process between variant parts model. In particular, KS is cost efficient when extensive sorting process, parts model misplaced and lack of space can be avoided.
Surface Morphologies of PVDF-TrFE/MgO Nanocomposite Thin Films and its Effect on the Ferroelectric Properties
Authors: Mohd Wahid Mohamad Hafiz , Mohd Dahan Rozana , Sa'ad Siti Zaleha , Arshad Adillah Nurashikin , Sarip Muhamad Naiman , Zulkefle Habibah , Mahmood Mohamad Rusop
Published: December 2015

The enhancement of ferroelectric and dielectric properties of PVDF-TrFE by incorporating various percentages of Magnesium Oxide (1 – 7%) for spin coated nanocomposite thin film was demonstrated. Observations showed uniform distribution and low agglomeration of MgO in the PVDF-TrFE nanocomposite thin film, especially for 3% MgO. Additionally, the 3% MgO incorporated into PVDF-TrFE had generated the highest Pr (88 mC/m2) and dielectric constant (13.6) in comparison other percentage compositions. However, the addition of more than 3% MgO filler loading caused a reduction in the ferroelectric and dielectric properties of the nanocomposite thin films.
Analysis of Micro-Porosity Defect and Remedial Measures in Crankshaft (Ductile Iron) – A Case Study
Authors: Mohamed Ibrahim Azalan , Musa Mohd Azam , Mohamad Noor Noraishah , Wan Saidin Wan Ahmad Najmudin , Rani Mohd Fadhil
Published: December 2015

This paper presents analysis of Micro-Porosity defect in product Crankshaft - Ductile cast iron (FCD 700/2), which has been carried out at one of Automotive Foundry Company in Malaysia. Systematic analyses like cause-effect diagram and defect diagnostic study approach were carried out to understand the root causes of the micro-porosity. From the data analysis there are two significant factors are identified that affect the formation of micro-porosity, they are mold factor and metal factor. Four remedial countermeasures have been proposed to prevent micro-porosity; increase squeezes pressure at molding machine, control sand moisture, increase radius at edge of mold, and reduce Magnesium (Mg) content. Result of the trials showed substantial reduction of micro-porosity defect in crankshaft (casting). The company has accepted the countermeasure and incorporated in the standard operation procedure.
Technology in Undersea Cable Systems: 50 Years of Progress
Authors: Thomas Robert , Rapp Ronald J. , Spalding Marsha A. , Stix Robert K. , Kordahi Maurice E. , Bergano Neal S.
Published: December 2015

AbstractUndersea cable systems provide a comprehensive example of how technology has changed during the 50-year publication history of the MTS Journal. From the 125-μm‐diameter glass optical fiber to the 12,000-ton cable ships, the design, manufacture, and
installation of undersea communication systems rely on a remarkable intersection of technologies. The technologies supporting this industry have progressed significantly in many aspects. In 1965, coaxial analog systems were transmitting 128 three-kilohertz channels that were amplified by vacuum-tube-based
amplifiers for consortiums of national telephone companies over simple point-to-point links. Today, a fiber-optic cable transmits 10 million times as much traffic, that is, tens of terabits of information per second, amplified by reliable erbium-doped fiber amplifiers, as part of mesh networks
serving datacom, offshore oil and gas facilities, and scientific applications, each under a variety of ownership and operational models. Installation technology has changed along with the transmission technology, with advances in cable route surveys, ship positioning, cable burial, and use
of remotely operated vehicles. System maintenance has become a much more practical endeavor since the advent of universal joint technologies and methodologies. Wet-mateable fiber-optic connectors enable remote, modular, subsea connection scenarios that serve a variety of applications. This
paper reviews some of the history and evolution of the technology used in undersea cable systems and addresses future industry trends.
Dengue Virus Nonstructural Protein 1–Induced Antibodies Cross-React with Human Plasminogen and Enhance Its Activation
Authors: Chuang Yung-Chun , Lin Jessica , Lin Yee-Shin , Wang Shuying , Yeh Trai-Ming
Published: December 2015

Dengue virus (DENV) infection is the most common mosquito-borne viral disease, and it can cause life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Abnormal activation of the coagulation and fibrinolysis system is one of the hallmarks of DHF/DSS. However, the mechanism underlying hemorrhage in DHF/DSS remains elusive. In previous studies, plasminogen (Plg) cross-reactive Abs, which can recognize DENV nonstructural protein (NS) 1, have been found in dengue patients. However, it is unclear whether these Abs are indeed induced by DENV NS1. Thus, we immunized mice with recombinant NS1 from both bacteria and drosophila to determine whether NS1 can induce Plg cross-reactive Abs. The results from the NS1-immunized mouse sera indicated that NS1 immunization induced Abs that could cross-react with Plg. To study the effects of these NS1-induced Plg cross-reactive Abs on fibrinolysis, we isolated several Plg cross-reactive anti-NS1 mAbs from these mice and found that some of them could enhance Plg activation. In addition, epitope mapping with a phage-displayed random peptide library revealed that one of these mAbs (2A5) could recognize NS1 C-terminal residues 305–311, which share sequence homology with Plg residues 590–597. A synthetic peptide of NS1 residues 305–311 could inhibit the binding of both 2A5 and its Fab to Plg and its enhanced activation. Thus, our results suggest that DENV NS1 can induce Plg cross-reactive Abs through molecular mimicry, which can enhance Plg activation and may contribute to the pathogenesis of DHF/DSS.
Tertiary Lymphoid Tissue Forms in Retinas of Mice with Spontaneous Autoimmune Uveitis and Has Consequences on Visual Function
Authors: Kielczewski Jennifer L. , Horai Reiko , Jittayasothorn Yingyos , Chan Chi-Chao , Caspi Rachel R.
Published: December 2015

During chronic inflammation, tertiary lymphoid tissue (TLT) can form within an inflamed organ, including the CNS. However, little is known about TLT formation in the neuroretina. In a novel spontaneous autoimmune mouse model of uveitis (R161H), we identified well-organized lymphoid aggregates in the retina and examined them for TLT characteristics. Presence of immune cells, tissue-specific markers, and gene expression patterns typically associated with germinal centers and T follicular helper cells were examined using immunohistochemistry and gene analysis of laser capture microdissected retina. Our data revealed the retinal lymphoid structures contained CD4+ T cells and B cells in well-defined zonal areas that expressed classic germinal center markers, peanut lectin (agglutinin) and GL-7. Gene expression analysis showed upregulation of T follicular helper cell markers, most notably CXCR5 and its ligand CXCL13, and immunohistochemical analysis confirmed CXCR5 expression, typically associated with CD4+ T follicular helper cells. Highly organized stromal cell networks, a hallmark of organized lymphoid tissue, were also present. Positive staining for phospho-Zap70 in retina-specific T cells indicated CD4+ T cells were being activated within these lymphoid structures. CD138+/B220+ plasma cells were detected, suggesting the retinal lymphoid aggregates give rise to functional germinal centers, which produce Abs. Interestingly, eyes with lymphoid aggregates exhibited lower inflammatory scores by fundus examination and a slower initial rate of loss of visual function by electroretinography, compared with eyes without these structures. Our findings suggest that the lymphoid aggregates in the retina of R161H mice represent organized TLT, which impact the course of chronic uveitis.
Evaluation of the galactogogue effect of silymarin on mothers of preterm newborns (<32 weeks)
Authors: Peila Chiara , Coscia Alessandra , Tonetto Paola , Spada Elena , Milani Silvano , Moro Guido , Fontana Carlotta , Vagliano Liliana , Tortone Claudia , Di Bella Elisa , Bertino Enrico
Published: December 2015

Hypogalactia has a relative high frequency in women having delivered preterm infants, who often have difficulties in maintaining a sufficient production of milk for their infants’ needs over prolonged periods of time. Recent studies have shown a potential galactogogue effect of silymarin on milk production in animal models (cows and rats) and in humans (mothers of term newborns); nonetheless, none of the studies conducted on humans consisted of double-blind randomized clinical trials and no data are available concerning mothers who delivered preterm infants. The aim of our study was to assess the efficacy of silymarin (BIO-C®) as galactogogue and its tolerability in mothers who delivered preterm infants. We enrolled 50 mothers at 10±1 days post-partum who had delivered infants at ® and placebo arms. No adverse events were observed in the 2 arms among mothers and infants, and silymarin and its metabolites were not detectable in the analyzed human milk samples. Further investigation on specific patient groups affected by hypogalactia, defined according to stricter criteria, should be planned to assess the efficacy of the product in increasing milk production.
Survival rate and neurodevelopmental outcome of extremely premature babies: an 8-year experience of an Italian single neonatal tertiary care center
Authors: Uccella Sara , De Carli Agnese , Sirgiovanni Ida , Schiavolin Paola , Damiano Giuseppe , Ghirardi Beatrice , Maglioli Carpano Francesca , Bassi Laura , Gangi Silvana , Picciolini Odoardo , Fumagalli Monica , Mosca Fabio
Published: December 2015

Extremely preterm babies are at major risk for adverse neurodevelopmental outcome, being the gestational age (GA) the main determinant for a good-quality survival. Aim of this retrospective study was to investigate the neurodevelopmental outcome in a population of extremely preterm babies admitted to a single neonatal tertiary care unit over an 8-year period. All babies born between 23+0 and 25+6 weeks of GA from January 2003 until December 2010 were retrospectively enrolled. Perinatal and neonatal variables were recorded. Motor and cognitive development was assessed using the neurofunctional scale (NFS) and the Griffith’s scales at 2 years. Fifty-five out of 122 infants survived to discharge. Survival rates doubled for each additional gestational week from 23 to 25: 16%, 38% and 74% at 23, 24 and 25 weeks GA respectively. Forty-six infants were evaluated at 2 years. A poor cognitive and motor outcome was observed in all babies born at 23 weeks. Griffith’s general quotient (GQ) was ≥76 in 62% and ≥88 in 33% of babies born between 24 and 25 weeks. No severe motor disabilities were found in 81% of babies born between 24 and 25 weeks. Preterm premature rupture of membranes, absence of prenatal steroids, intrauterine growth restriction, male, lower GA and major brain abnormalities at magnetic resonance imaging (MRI) were significantly associated with worse NFS and lower mean GQ at 2 years of age. GA, gender and abnormal MRI findings remained significantly associated with impaired NFS at the multivariate analysis. Survival rates and neurodevelopmental outcome improved with each week of GA. These results are relevant for clinicians counselling families facing an unavoidable extremely preterm birth.
MODELING OF MIXED LIQUOR VOLATILE SUSPENDED SOLIDS AND PERFORMANCE EVALUATION FOR A SEQUENCING BATCH REACTOR
Authors: Mirbagheri Sayed Ahmad , Bagheri Majid , Ehteshami Majid , Bagheri Zahra , Pourasghar Masoud
Published: December 2015

This study examined carbon, nitrogen and phosphorous removal from municipal wastewater in a sequencing batch reactor and biokinetic coefficients were evaluated according to results of BOD and COD. Furthermore, the MLVSS in the aeration reactor was modeled by using multilayer perceptron and radial basis function artificial neural networks (MLPANN and RBFANN). The experiments were performed so that the cell retention time, filling time and intensity of aeration were (5, 10 and 15 d), (1, 2 and 3 h) and (weak, medium and strong) respectively. The result indicated that with cell retention time of 15 d, filling time of 1 h, aeration time of 6 h and settling time of 3 h the HRT is optimized at 10 h. The BOD5, COD, TP, TN and removal efficiencies were 97.13%, 94.58%, 94.27%, 89.7% and 92.75% respectively. The yield coefficient (Y), decay coefficient (Kd), maximum specific growth rate (K) and saturation constant (Ks) were 6.22 mgVSS/mgCOD, 0.002 1/d, 0.029 1/d and 20 mg COD/L according to COD experimental data. The values of the biokinetic coefficients were found to be as follows: Y = 10.45 mgVSS/mgBOD, Kd = 0.01 1/d, 0.014 1/d and 3.38 mgBOD/L according to BOD5 experimental data. The training procedures for simulation of MLVSS were highly collaborated for both RBFANN and MLPANN. The train and test models for both MLPANN and RBFANN demonstrated perfectly matched results between the experimental and the simulated values of MLVSS. The values of RMSE for train and test (verification) models obtained by MLPANN were 31.82 and 40.25 mg/L respectively, and the value of R2 was 0.99 for both models. The values of RMSE for train and test models obtained by MLPANN were 69.04 and 43.87 mg/L respectively, and the value of R2 was 0.99 for both models. It was observed that the MLPANN has stronger approximation and generalization ability than the RBFANN with regard to our experimental data for MLVSS.
Treatment method and restorative material preferences of dental practitioners
Authors: Vural Uzay Koç , Gökalp Saadet
Published: December 2015

Objective: The present study is aimed to investigate the preference profiles of treatment methods used by private dental practitioners in Ankara for deep carious lesions of mature permanent teeth. Methods: Private dental practitioners (general/specialist), in five districts of Ankara, were provided with a questionnaire comprising demographic characteristics and their preferred treatment methods for two simulated clinical cases related to deep caries excavation technique for anterior (Case A) and posterior, permanent teeth (Case B) with restorative material choices. The questionnaire was delivered personally to the participants who accepted the invitation. Documentation was retrieved back at another appointment after 1–3 weeks intervals. Data were analyzed using frequency analysis and Chi-square tests. Results: A total of 371 dentists, aged 25–69 years, took part in the study representing a response rate of 51.38%. Valid responses were 328 (168 males and 160 females) due to incomplete questionnaires. In Case A, complete caries excavation was the preferred treatment method (62.5%) followed by stepwise excavation (28.4%). Dentists, who had an excessive workload, indicated a stepwise excavation treatment significantly less than the dentists who had less workload (P = 0.001). In Case B, the preferences were narrowly distributed between complete caries excavation (50.9%) and stepwise excavation (42.4%). Composite restoration (31.7%) was more selected than amalgam (27.1%) with complete excavation technique. Workload has no effect on the treatment options of the posterior tooth with deep dentin caries. Conclusion: Dentists mostly adopted traditional caries removal technique. There is no uniform treatment method of deep carious lesions among dentists in anterior and, especially in posterior regions in Ankara, Turkey.
Comparison of chemomechanical caries removal using Papacárie versus conventional method in children
Authors: Almaz Merve Erkmen , Sönmez Işıl Şaroğlu , Oba Aylin Akbay
Published: December 2015

Purpose: The purpose of this study was to investigate the clinical efficacy of chemomechanical caries removal (Papacárie), compared with the conventional method. Materials and Methods: The study consisted of 50 primary molars selected from 25 healthy children (mean age 7.6 ± 1.1). Each patient had at least two primary molars with approximately equal-size caries lesions. Both treatments were carried out in the same session. Before and after treatment, fluorescence values were obtained using DIAGNOdent Pen and time needed for caries removal was recorded. Each patient was asked whether he/she felt any pain, requested for local anesthesia, which treatment he/she preferred, and behavior of the patient during caries removal was assessed. Data were analyzed using McNemar, Wilcoxon signed rank, and Mann-Whitney U-test. Results: The clinical evaluation revealed that all the cavities were caries free after both techniques. Comparison of the difference in fluorescence values showed that readings were lower after conventional method (P < 0.05). The time taken for chemomechanical caries removal was approximately 2 times longer (t-test). There was no difference between two methods in terms of pain and patient behavior (P < 0.05). Conclusion: Chemomechanical caries removal and conventional method exhibited similar efficacy in caries removal.
Comparison of shear bond strength of self-adhering flowable composite with different flowable composites to dentin
Authors: Almaz Merve Erkmen , Oba Aylin Akbay , Sönmez Işıl Şaroğlu , Sönmez Deniz
Published: December 2015

Purpose: The purpose of this study was to measure and compare the shear bond strength of a self-adhering flowable resin composite with different flowable composites to dentin. Materials and Methods: A total of 48 extracted teeth were divided randomly into four groups, and dentin surfaces were exposed. Following materials were applied to dentin surfaces; Group I: VF (self-adhering flowable composite), Group II: CSE Bond (two-step self-etch adhesive) + CMF (conventional flowable composite), Group III: AB SE (one-step self-etch adhesive) + AF (conventional flowable composite), Group IV: AEO (one-step self-etch adhesive) + FUF (conventional flowable composite). The specimens were subjected to shear loading using a universal testing machine. The type of failure was detected with an illuminated microscope. One-way analysis of variance and Tukey multiple comparison test were used to determine statistical significance differences between groups. Results: Mean shear bond strength values were ranked as follows; Group II < Group IV < Group III < Group I. Statistically significant differences were found among all groups (P < 0.05). Conclusion: Group I; the self-adhering flowable resin composite had the lowest shear bond strength values while Group II; showed the highest shear bond strength among the materials tested.
Oral glucose tolerance test in unstimulated saliva of healthy individuals
Authors: Mirzaii-Dizgah Mohammad-Hossein , Mirzaii-Dizgah Iraj , Mirzaii-Dizgah Mohammad-Reza
Published: December 2015

Objective: The aim of this study was to investigate oral glucose tolerance test (OGTT) in unstimulated whole saliva as a diagnostic specimen in clinical practice for detection of diabetes mellitus (DM). Materials and Methods: An interventional study was carried out in 30 apparently healthy individuals aged 24-59 years. Serum and saliva samples were obtained in fasting, 1 h and 2 h after glucose intake (75 g). Glucose concentration was determined by enzymatic colorimetric glucose oxidase-prostatic acid phosphatase assay. Statistical analysis of the repeated ANOVA (followed Bonferroni post-hoc test) and Pearson correlation coefficient were used. Results: The mean serum glucose concentration was significantly higher 1 h after glucose intake (152.32 ± 31.06) than both fasting state (106.38 ± 41.08; P < 0.001) and 2 h after glucose intake (125.21 ± 51.71; P < 0.001). Saliva glucose was also significantly higher 1 h after glucose intake (5.46 ± 2.41) than both fasting state (2.84 ± 1.46; P < 0.001) and 2 h after glucose intake (4.01 ± 1.91; P < 0.001). There were significant positive correlation between saliva and serum glucose concentration in fasting state (r = 0.502; P = 0.044), 1 h (r = 0.756; P = 0.0001), and 2 h (r = 0.543; P = 0.023) after oral glucose intake. Conclusion: It seems that unstimulated saliva can be used as an alternative to serum for diagnosis of DM in OGTT.
Land Use Influences Mosquito Communities and Disease Risk on Remote Tropical Islands: A Case Study Using a Novel Sampling Technique
Authors: Meyer Steiger Dagmar B. , Ritchie Scott Alex , Laurance Susan G. W.
Published: December 2015

Land use changes, such as deforestation and urbanization, can influence interactions between vectors, hosts, and pathogens. The consequences may result in the appearance and rise of mosquito-borne diseases, especially in remote tropical regions. Tropical regions can be the hotspots for the emergence of diseases due to high biological diversity and complex species interactions. Furthermore, frontier areas are often haphazardly surveyed as a result of inadequate or expensive sampling techniques, which limit early detection and medical intervention. We trialed a novel sampling technique of nonpowered traps and a carbon dioxide attractant derived from yeast and sugar to explore how land use influences mosquito communities on four remote, tropical islands in the Australian Torres Strait. Using this technique, we collected > 11,000 mosquitoes from urban and sylvan habitats. We found that human land use significantly affected mosquito communities. Mosquito abundances and diversity were higher in sylvan habitats compared with urban areas, resulting in significantly different community compositions between the two habitats. An important outcome of our study was determining that there were greater numbers of disease-vectoring species associated with human habitations. On the basis of these findings, we believe that our novel sampling technique is a realistic tool for assessing mosquito communities in remote regions.