bluuebunny/crossref_metadata_2025 huggingface dataset:
Probability and Statistics Apps for Mobile Devices
Authors: Edwards Howard P
Published: July 2015

Mobile devices such as tablets and smartphones are rapidly replacing laptops and notebooks as the primary student e-learning device. This chapter discusses the needs of a Statistics app user and how these differ from the needs of users of other Mathematics apps, and then reviews some the mobile apps currently available which enable a user to either learn Statistics or to carry out the sorts of summaries and analyses encountered in an undergraduate Statistics course. Implications of these apps for both teaching and learning are discussed.
Microworlds
Authors: Cork Stuart
Published: July 2015

This chapter combines the well-researched area of mathematics education, linear equations, with the field of mathematical microworlds. Insights into the current knowledge of both areas are presented before focusing the discussion on a new study in which pre-secondary school learners, with no prior formal teaching on the topic, explore linear equations through an algebra-based microworld called DragonBox. DragonBox is a touch-enabled mobile application available on all major platforms and to which the author has no affiliation. Touch-enabled mobile devices have great potential as vessels for mathematical microworlds and this chapter draws conclusions regarding the influence such microworlds have on a learner's understanding. Although learners in this study demonstrated procedural fluency when working with DragonBox, it was only through encouraged reflection that a relational understanding seemed to take effect and without it the children developed inconsistent notions about the structure of the microworld.
Automatic Diagnosis of Brain Magnetic Resonance Images based on Riemannian Geometry
Authors: Gouskir Mohamed , Bouikhalene Belaid , Aissaoui Hicham , Elhadadi Benachir
Published: July 2015

Automated brain tumor detection and segmentation, from medical images, is one of the most challenging. The authors present, in this paper, an automatic diagnosis of brain magnetic resonance image. The goal is to prepare the image of the human brain to locate the existence of abnormal tissues in multi-modal brain magnetic resonance images. The authors start from the image acquisition, reduce information, brain extraction, and then brain region diagnosis. Brain extraction is the most important preprocessing step for automatic brain image analysis. The authors consider the image as residing in a Riemannian space and they based on Riemannian manifold to develop an algorithm to extract brain regions, these regions used in other algorithm to brain tumor detection, segmentation and classification. Riemannian Manifolds show the efficient results to brain extraction and brain analysis for multi-modal resonance magnetic images.
Genetic Algorithm Learning of Nash Equilibrium
Authors: Outanoute M'hamed , Baslam Mohamed , Bouikhalene Belaid
Published: July 2015

To select or change a service provider, customers use the best compromise between price and quality of service (QoS). In this work, the authors formulate a game theoretic framework for the dynamical behaviors of Service Providers (SPs). They share the same market and are competing to attract more customers to gain more profit. Due to the divergence of SPs interests, it is believed that this situation is a non-cooperative game of price and QoS. The game converges to an equilibrium position known Nash Equilibrium. Using Genetic Algorithms (GAs), the authors find strategies that produce the most favorable profile for players. GAs are from optimization methods that have shown their great power in the learning area. Using these meta-heuristics, the authors find the price and QoS that maximize the profit for each SP and illustrate the corresponding strategy in Nash Equilibrium (NE). They also show the influence of some parameters of the problem on this equilibrium.
Processing of Injection Moulded of Synthesized HAp by Single Step Wick-Debinding and Sintering
Authors: Ali Nurul Huda M. , Subuki Istikamah , Ismail Muhammad Hussain
Published: July 2015

The present study was conducted to investigate the possibility of merging the wick-debinding and sintering of injection-molded ceramic parts into a single-step operation. In this study, the synthesized hydroxyapatite (HAp) feedstock prepared was injection moulded according to ASTM standard C1424-10 to produce green specimens. The green specimens were then debound and sintered through a single step wick-debinding and sintering process by using alumina powder as an embedment agent. The principle of this method is that it carried out at a temperature where the binder is melt, allowing it to flow out of the specimens into pores in the contacting of substrate. Once, the binder is successfully removed from the specimens, sintering process is took place to bond the particle together leading to densification of sintered specimens. From the results, it shows that the binders were successfully removed from the green specimens by capillary suction of the molten binder and single phase of HAp was presented at the sintering temperature of 1000°C.
Aspergillus niger ATCC 16404 Producing Pectinase Couple to Polysulfone/Pluronic Membrane Ultrafiltration for Momordica Charantia Juice Clarification
Authors: Mohd Rais Nurul Atikah , Idris Norazlina , Abdul Manaf Shareena Fairuz , Habibun Hasnizah , Raslan Rafeqah , Mat Sahari Nur Farhana , Shahruddin Munawar Zaman , Hamzah Fazlena
Published: July 2015

Momordica charantia is an anti-diabetic which is used as carminative, emmenagogue, in the treatment of colics, as antiviral, anthelmintic, antimalarial and antimicrobic remedy. The Momordica charantia was treated with Aspergillus niger pectinase at various concentration (0-500 U/ml), temperature (4-40°C) and times (0-10 min). Aspergillus niger was selected as a promising producer of pectinase via solid state fermentation (SSF) using oil palm leaf (OPL) as substrate because it is abundantly available in Malaysia and rich with carbon source that needed for Aspergillus niger’sgrowth. The optimum treatment conditions were at 30°C, at pH between 6-6.5 at time 10 min with 472.257 U/ml. The enzymatic treatment was followed by ultrafiltration (15kDa). Analysis of the clarified juice indicate that the enzyme permitted a higher permeate flux and high juice quality.
Epipremnum pinnatum Activity on Chick Pancreatic Lipase
Authors: Hamzah Fazlena , binti Mohd Yusop Fatin Hafizah , Abdul Manaf Shareena Fairuz , Yahya Asdarina
Published: July 2015

Epipremnum pinnatum is a vegetative, type of vines and climbing plant that can be found in a semitropical and tropical country in South East Asia and Asian region. It has been used as folk remedies due to its medicinal properties and capability in enhancing the immune system. However, limited scientific data are present to support this claim. Thus, the present study was focused on the determination of phytochemical properties of the extract E. pinnatum and the effect on the pancreatic lipase inhibitory activities. Phytochemical of E. pinnatum was extracted using supercritical carbon dioxide (CO2) at 6000 psi and 40°C. The extracted oil was analyzed using Follin- Ciocalteu method to determine the phenolic components and followed by gas chromatography analysis. Chicken pancreas was used to investigate pancreatic lipase inhibitory activities of the extracted E.pinnatum. The results indicated that extract E.pinnatum could inhibit the chicken pancreatic lipase activity and based on the analysis obtained, the amount of lipase activity inhibited was 74 % by using 48 μg/ml of extract E.pinnatum.
Fatty Acid Methyl Ester (FAME) Production from Waste Cooking Oil
Authors: Saadon Norkamruzita , Mohd Yusof Nor Ashikin , Razali Noraini , Mat Yashim Marshahida , Roslan Amira Khairin
Published: July 2015

Biodiesel is clear liquid with a light to dark yellow color. Biodiesel is one of the alternative fuels that are attractive because of its favorable characteristics such as being non-toxic, biodegradable, renewable, carbon neutral and low emission. Fatty acid methyl ester (FAME) is a type of biodiesel. In this study, it was produced by using transesterification of waste cooking oil (WCO) which was reacted with methanol and heterogeneous catalyst. The two heterogeneous catalysts that were used in this study were sodium (Na) metal hydroxide supported on oil palm frond (OPF) and Na metal supported on oil palm kernel shell (OPKS). The support metal used was sodium hydroxide solution (NaOH). OPF and OPKS were used as they are the major residues obtained from the oil palm plantation that covers approximately 14.72% of Malaysian’s total landmass. The parameters that in this study were the reaction temperatures of the transesterification process from 30°C to 60°C and the catalyst loading from 0.5wt% to 3wt%. The reaction time and ratio methanol to oil were kept constant which were 4 hours and 1:10 respectively. This experiment was conducted in order to investigate the effect of two different heterogeneous catalysts on both temperature and catalyst loading on the yield production of FAME. The results were obtained by using GCMS analysis. From the experiment that was conducted, the results of FAME production by using two different catalysts indicate that the higher the reaction temperature is, the higher the production of FAME which is at 60°C. It also shows that the percentage yield of FAME increases with the increase of catalyst loading until it reaches the best value which is at 1wt%.
Isobutanol Production and Alcohol Tolerance by Yeast Wild Strain
Authors: Nor Azah Ramli , Roshanida A. Rahman
Published: July 2015

Recently, there have been global movements toward reducing the use of fossil resources as source of energy due to continuous depletion of petroleum fuel-reserves besides contributing to environmental problems such as greenhouse effect, global warming and climate change. Isobutanol is one of biomass-based fuels that has been recognizes for its potentiality as fuel additive or substitute due to its attractive physical properties. This paper investigates the production of isobutanol and alcohol tolerance by five different types of yeast (Saccharomyces cerevisiae, Kluyveromyces lactis GG799 and Pichia pastoris KM71H, GS115 and X33) in batch fermentation. Based on the result obtained, P. pastoris X33 produced the highest concentration of isobutanol at 65 mg/l followed by P. pastoris GS115, K.lactis GG799, P. pastoris KM71H and S. cerevisiae with concentration of 57 mg/l, 49 mg/l 49 mg/l and 46 mg/l respectively. This result proves that yeast is able to produce isobutanol naturally. S. cerevisiae has been proven as good yeast in alcohol tolerance as it was capable to grow in more than 2% isobutanol and butanol of up to 2%. Among the different alcohols tested for alcohol tolerance, 3-methyl-1-butanol has the highest toxicity towards yeast growth as compared to isobutanol and butanol.
Microwave Drying Characteristics and Antidiabetic Properties of Aquilaria subintegra and Aquilaria malaccensis Leaves
Authors: Yunus Sxureha , Md Zaki Nurul Asyikin , Ku Hamid Ku Halim
Published: July 2015

The present study was aimed to investigate the effect of microwave drying on the anti-diabetic potential of the leaves of Aquilaria subintegra and Aquilaria malaccensis with regard to its efficacy by local herbalists in the treatment of diabetes frailties. The drying process was carried out at 50, 100 and 150 W, and the drying curves were developed to analyse the drying characteristics of both species of Aquilaria leaves. Solid-liquid extraction was done by using ethanol as solvent prior to in-vitro analysis of the inhibition activity on α-amylase. Following that, HPLC and FTIR were done to support findings on the antidiabetic compounds of the leaves extract. The results indicated that an increase in power level will reduce the drying time during microwave treatment. Findings showed that both species of Aquilaria leaves extract could remarkably inhibit the activity of α-amylase and provide a rationale for the use of the leaves in the treatment of diabetes mellitus.
Potential Antipyretic Agents from Plants: An Overview
Authors: Afiffudden Siti Khairun Nissa , Alwi Habsah , Ku Hamid Ku Halim
Published: July 2015

Plants are well known for its various uses since ancient times. Plants contribution in various fields such as medical, pharmaceutical and food industry bring a lot of benefits to human capital. Especially in the medical field, plants are major contributors for medicinal drugs as it itself is rich in various medicinal agents. One of the illness that can be treated by using plants is fever. Fever can be treated by consuming non-steroids anti-inflammatory drugs (NSAIDS). However, excessive intake of synthetic drugs bring a lot of harm to the human body especially to the internal organs. Traditionally, various plant is used to cure fever, which directly indicate plants are the best sources of natural antipyretic. Thus, in this present review, activity of natural antipyretic extracted from various plants towards fever will be explained. In this review paper, Google Scholar, PubMed, ScienceDirect were the sources for the published article to collect information regarding antipyretic activity. A number of 32 articles on 10 plant species are found to address antipyretic activities. This review concludes that antipyretic activity can be found indicatively in various plants throughout the world.
Racemic Ibuprofen Morphology: Molecular Modelling and Experimental
Authors: Lukman Zulfahmi , Anuar Nornizar , Abdul Rahman Norazah
Published: July 2015

Crystal morphology remains an important aspect in pharmaceutical industries and thus lengthy experimentally determined morphology becomes a routine. This leads to advancement of molecular modeling to assist in crystal morphology determination. Morphology of racemic ibuprofen can be grown in PEG 300 solvent and simulated via molecular modeling, the computational technique. The resulting morphology dictates its feasibility and prepares for further necessary control to produce desired morphology. Tuning up the morphology can be done by rationalizing out via molecular modeling the effect of the solvent and crystallization method. Solvent effect persists to influence crystal morphology mainly via interaction of hydrogen bond specific at different facets. However, the influence of solvent-surface interaction in enhancing or inhibiting crystal growth is still not completely resolved. To date, racemic ibuprofen grown in PEG 300 solvent is the first ever reported. The objective of this study is to compare experimental and predicted morphology of racemic ibuprofen using selected potential functions and charge set in vacuum condition. Racemic ibuprofen crystal morphology was grown in PEG 300 solvent via cooling at ambient temperature and predicted via attachment energy (AE) method using molecular modeling. It was found that the experimental morphology is tabular hexagonal while the predicted one is tabular octagonal. The facets were cleaved and its surface chemistry was explained. The predicted lattice energy with lowest percentage error of 0.02% is dominated by van der Waals force rather than electrostatic force.
Electrochemical Properties of Electrodeposited MnO2 Nanoparticles
Authors: Ali Gomaa Abdelgawad Mohammed , Yusoff Mashitah Mohd , Chong Kwok Feng
Published: July 2015

The present study shows the electrodeposition of MnO2 from KMnO2 solution and its electrochemical studies. XRD analysis shows the electrodeposited MnO2 has nano-sized particle of 18 nm. The electrochemical properties have been investigated using the cyclic voltammetry, galvanostatic charge/discharge and impedance techniques. The electrodeposited MnO2 shows good electrochemical behavior with high specific capacitance value of ca. 306 F g-1. Moreover, it shows high capacitance stability of 90% over 1000 charge/discharge cycles. Impedance result shows low solution resistance and charge transfer resistance, an indication of the conductive nature for the electrodeposited film.
Morphological Analysis of Photodegradable Polyethylene Films for Agricultural Use
Authors: Mohd Yusak Nurul Akidah , Mohamed Rahmah , Mohamed Mohaimi , Talib Siti Sarah A.
Published: July 2015

The application of photodegradable polyethylene is increasingly important for agricultural uses due to its ability to degrade after suggested shelf life and to counter measure pollution issue caused by conventional polyethylene films. The photodegradable polyethylene (PE) mixtures were formulated with added polypropylene (PP) and photodegradant (RM master batch) and tested in oil palm seedlings cultivation. PP is known to have photodegradable ability and RM master batch is proven to induce photo degradation of polyethylene. Thus, the mixture of these three components according to different ratios was processed into agricultural plastic films. There are four formulations that are tested in this study, namely T1 (80% PE:20% PP:5% RM master batch), T2 (70% PE:30% PP:5% RM master batch), T3 (80% PE:20% PP:3% RM master batch) and T4 (70% PE:30% PP:3% RM master batch). All formulations except control sample were added with photodegradant to impart degradation reaction and compatibiliser was also affixed to allow coalesce between polyethylene and polypropylene. Carbon black was added 0.5% into the formulation as for poly bags application, dark environment of soil is crucial for root development and growth. Penetration of sun light into the planting soil could commence development of shoot instead of root growth. All four formulations showed observable morphological changes on microscopic images on the surfaces after being used in oil palm nursery. From the study, it is shown that T1 and T3, with 20% of additional polypropylene had demonstrated clear surface disintegration when viewed microscopically. The addition of 3% and 5% of photodegradant into the formulations did not show any expressive difference thus suggesting that 3% of photodegradant is the optimum amount to induce photo degradation.
Drilling Fluid Design for Shale Gas Drilling
Authors: Zazarli Shah Mohamad Safwan , Sauki Arina , Wan Bakar Wan Zairani , Ghazali Nurul Aimi , Azizi Azlinda
Published: July 2015

Shale gas nowadays is an important source of unconventional gas. The limited conventional gas supply makes the unconventional sources as a new source of gas. In this research, the aim is to design a mud formulation that can carry out essential functions of mud for shale gas drilling. Commonly for shale gas drilling, water based mud is used. However, water based mud is ineffective when dealing with water-sensitive shale. The alternative way to deal with this type of shale is using synthetic-based mud (SBM) or oil-based mud (OBM). OBM is an effective mud while drilling well. However, it is toxic and gives negative impact to environment. SBM somehow is more environmental friendly compared to oil based and ester is one of the synthetic based fluids. In order to prove this statement, a toxicity test was carried out to investigate the impact of ester based mud on selected marine life. The results of the test were compared with past research results. The ester use in this research is methyl-ester C12-C14 derived from palm oil and the mud was formulated at different oil-water ratios which are 70/30, 80/20 and 90/10, respectively and the best rheological performance can be seen at 80/20 oil-water ratio. Then, the performance of this mud had been compared to other types of mud which are sarapar-based and WBM. The findings revealed that the rheological performance of ester based mud is comparable with common based mud used for shale gas drilling. Apart from that, it is less toxic than other based mud which can maintain 60% prawn’s survival even after 96 hours exposure in 100,000 ppm of mud concentration in artificial seawater.
The Characteristic Study of Oil Palm Kernel Expeller as Lost Circulation Material in Water Based Drilling Mud (WBM)
Authors: Ghazali Nurul Aimi , Jaih M.Z.M. , Mohd T.A.T. , Alias Nur Hashimah , Azizi Azlinda , Yahya Effah
Published: July 2015

When drill in a highly permeable zone the common problem faced by the operator is lost circulation of drilling mud into the formation. Lost circulation of mud are costly and therefore lost circulation materials (LCM) being introduced to the mud formulation to prevent lost circulation from the formation. Since Malaysia is the one of the major country producer of Palm kernel Oil (PKO) with the high production of crude fibre from palm kernel (palm kernel expeller), thus this study was carried out to determine the ability of Palm Kernel Expeller (PKE) to be used as LCM in drilling mud. PKE used was in granule form by cause of pressing under high pressure compress to remove palm oil. Rheological and API filtration test were carried to determine the characteristic PKE in drilling mud. Water based mud (WBM) sample was used in this study with four (4) different concentration of PKE. The results show the filter cake formed was improved as the concentration increased and the filtrate loss reduced. SEM data also shows the ability of PKE to form a bridge across the pore thus reducing the loss of filtration.
Effect of Solvent Evaporation Time on CO2/CH4 Gas Performance for Poly(Lactic) Acid Membranes
Authors: Jami’an Wahida Nor Rasyiada , Hasbullah H. , Mohamed Fadilah , Rani Ahmad Rashid Ahmad , Saman Muhamad Farhan Kamarun , Binti Yusof Norhaniza , Ibrahim Norazana
Published: July 2015

Membrane technology in gas separation application was commercialized approximately 30 years ago because of a number of advantages offered compare to the conventional technique. The use of poly (lactic acid) (PLA), a biodegradable polymer, as a membrane material would assist the reduction of depending to petroleum-based polymer. This study investigated the effect of evaporation time to the gas separation performance of PLA membrane. Membrane prepared from polymer solution consist of PLA and dicholoremethane (DCM) as solvent was fabricated using pneumatically controlled casting system with dry/wet phase inversion method. Permeation test was conducted using pure carbon dioxide and methane gas. The results revealed that as the evaporation time increased, the pore size and surface porosity decreased, while the skin layer thickness increased. Although the morphology of the prepared membranes showed the desirable structure, the gas separation performance of the membrane prepared with polymer concentration of 15wt% and 60s evaporation time was found to be promising but not yet commercially ready.
Neural Wiener Based Model Predictive Control (NWMPC) for MTBE Catalytic Distillation Using Reduced Sequential Quadratic Programming (RSQP)
Authors: Sudibyo Sudibyo , Murat Muhamad Nazri , Aziz Norashid
Published: July 2015

Reactive distillation is a process that combines both reactor and distillation column in one unit process. The reactive distillation is normally applied in MTBE production in order to achieve high reaction conversion and purity of the MTBE. Controlling such reactive distillation is a challenging task due to its highly nonlinear behavior and the existence of strong interactions among control variables. In this work, a Neural Wiener based model predictive control (NWMPC) is designed and implemented to control the tray temperature of MTBE reactive distillation. The Reduced SQP (RSQP) has been embedded as an optimizer in the NWMPC proposed. The MTBE reactive distillation has been modeled using aspen dynamic and the control study has been simulated using Simulink (Matlab) which is integrated with Aspen dynamic model. The results achieved show that the NWMPC is able to maintain tray temperatures at desired set points, able to reject the disturbance and robust toward robustness test conducted.
Analysis of Heavy Metal Compositions in Shah Alam Multi Storey House
Authors: Ismail Zitty Sarah , Mohd Yasim Nurzulaifa Shaheera Erne , Mazlan Farhana , Mohd Zaki Suhanom
Published: July 2015

The purpose of the present study is to identify and to analyze of selected elemental composition in a multi storey house. The concentrations of heavy metals (Cd, Cu, Fe, Ni, Pb and Zn) were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES) after digestion with nitric acid and sulphuric acid. The results showed that the highest concentration of heavy metals in eight investigated microenvironment was Fe. The heavy metals concentration were in the order of Fe > Cr > Zn > Cu > Pb > Mn > Ni. All six heavy metals concentration at four different levels of multi storey house were followed the order of Level 1 > Level 2 > Level 3 > Level 4. The correlation analysis was applied to metals variable in order to identify the sources of airborne contaminant.It was indicated that the possible contributor heavy metals in multi storey houses were originated from outdoor sources such as vehicle exhausts, street dust and indoor sources such as cooking, smoking, and cleaning activities.
Experimental Comparison between Moving Bed Biofilm Reactor (MBBR) and Conventional Activated Sludge (CAS) for River Purification Treatment Plant
Authors: Mohd Sidek Lariyah , Mohiyaden Hairun Aishah , Basri Hidayah , Salih Gasim Hayder Ahmed , Birima Ahmad Hussein , Ali Zuraidah , Mohd Sabri Ahmad Fauzan , Md. Noh Md. Nasir
Published: July 2015

Moving Bed Biofilm Reactor (MBBR) systems have been proven as an effective technology for water treatment and have been used for Biochemical Oxygen Demand/Chemical Oxygen Demand (BOD/COD-removal), as well as for nitrification and denitrification in municipal and industrial wastewater treatment. Conventional Activated Sludge (CAS), in particular, has been extensively used in wastewater treatment since decades ago. In this study, physical performance results for both MBBR and CAS were compared and evaluated on laboratory scale basis. The study aims to identify the best system performance in terms of constituent removal efficiency for effective management of the river purification plant. A novel parallel MBBR and CAS pilot plant were fabricated and operated to compare the physical performance of MBBR and CAS. Analysis of the performances for MBBR and CAS show, MBBR has higher COD (85%), AN (75%) and TSS (80%) removal rate compared to CAS COD (53%), AN (53%) and TSS (69%). For BOD removal rate, CAS shows 68% removal rate whereas MBBR shows only 65%. Thus CAS has shown slightly higher removal rate than MBBR. In terms of sludge production, MBBR sludge is less than CAS. Overall performance proves that MBBR has better rate of constituent removal efficiency compared to CAS in the laboratory basis study.
Studies on Power Generation and Wastewater Treatment Using Modified Single Chamber Microbial Fuel Cell
Authors: Nik Azmi Nik Mahmood , Ghazali Nazlee Faisal , Fikri Ahmad , Ali Md Abbas
Published: July 2015

A membrane-less and mediator-less system was designed and tested with wastewater sample as fuel to generate electricity. Microorganisms were first isolated from the wastewater sample to pure culture and were used as the ‘machinery’ that converts wastewater into energy. The wastewater samples were treated either by sterilization or non-sterilization methods. These tests were run using a modified air-cathode single chamber microbial fuel cell (MFC). By sterilizing the wastewater, the calculated power density was much lower compared to non-sterilized wastewater indicating a significant role of microbial activity in the SCMFC system and substrate availability. Furthermore, mixed culture was observed to give larger power density compared to an individual microbe (18.42 ± 5.84 mW/m2 for mixed culture and 8.82 ± 4.56 mW/m2 to 9.46 ± 4.87 mW/m2 for individual microbe, Bukholderi capecia and Acidovorax sp. respectively) to prove that larger power value could be achieved with a mixed microbial system. In addition, the system proved to remove 68.57% of chemical oxygen demand (COD) of the wastewater sample tested. In conclusion, the designed SCMFC has been proven capable of power generation and wastewater treatment comparable to other SCMFCs to date.
Issues and Challenges on Sustainable Construction in Malaysia: Current Development of Refurbishment Activities
Authors: Mokhtar Siti Nazziera , Mahmood Noor Zalina , Che Hassan Che Rosmani
Published: July 2015

AbstractPurpose: The aim objective of this paper is to identify the current scenario of refurbishment activities/projects in Malaysian context.Problem Statement: From the literature review and initial research among the construction authorities, it was found that refurbishment activities have not looked into by the relevant agencies though Malaysia has embarked on construction for the past 50 years. Therefore, there is an urgent need for Malaysian construction authority and industry to conduct detailed study in refurbishment area specifically on a lack of comprehensive and accurate data on the value number of refurbishment projects in Malaysia and reducing the refurbishment waste generation.
Scheduled Waste Management in Malaysia: An Overview
Authors: Che Jamin Noorhidayah , Mahmood Noor Zalina
Published: July 2015

Industry has become an essential part of modern society, and waste production is an inevitable outcome of the developmental activities. A material becomes waste when it is discarded with impunity and may pose a potential hazard to the human health or the environment (soil, air, waste) when improperly treated, stored, transported or disposed off or managed. In other words, scheduled waste contributes a major share towards environmental degradation. Scheduled and hazardous waste is the most difficult waste to be managed due to the dangerous elements not only for the environment but also for public health. In Malaysia, in the last two decades, the waste management has been a major concern. Malaysia has developed a comprehensive set of legal provisions related to the management of toxic and hazardous wastes. In this work, an evaluation of the scheduled waste management in Malaysia is made: in term of legislation framework, type of wastes and waste volume production.
Production of 3D Parts from Wood Chips in a Closed Mold Process
Authors: Hartmann Robert , Koch Michael
Published: July 2015

The application-oriented distribution of wood chips is a major obstacle in the production of 3D molded composite parts made of plastics and wood. Similar to fibers in conventional fiber-reinforced plastic components long chips can be used for force transmission. Short chips and wood powder can be distributed homogeneously between longer chips to increase the wood volume percentage and to allow post-processing-free edge areas. The applied process parameters during the incorporation of the matrix material determine the filling of the cavity and the impregnation of the chips. Different formaldehyde-free resin and adhesive systems, as well as thermoplastic powders are used as matrix material. By controlling the subsequent pressing process of the oriented and impregnated chips the density and wall thickness of the molded part can be influenced. In this work different production process variants and a concept for a modular 3D experimental mold are investigated. The flowability and bulk density of the wood chip fractions are characterized and the compression pressure required in the production process is determined. Initial tests with a panel mold are carried out and the bending strength of the manufactured specimen is examined.
Bio-Pultrusion of Façade-Profiles from Sustainable Materials
Authors: Witt Martin Uwe , Milwich Markus , Gresser Götz T. , Hammer Manfred , Knippers Jan
Published: July 2015

Fiber reinforced plastics, due to their good mechanical properties and simultaneously low density, are very attractive for many uses. They are also gaining more importance in the civil engineering applications. Bio composites based on sustainable raw materials are becoming much more attractive, especially in construction industry, due to their recyclability and eco balance benefits. In this paper, a method to develop a façade profile from regenerated viscose filament and bio resin system (PTP®) using pultrusion process is discussed. The PTP® resin system from Bio-Composites And More GmbH comprises of 60% epoxidized vegetable oil. The pultrusion process is optimized to reach 60 cm/min speed from the initial speed of 4 cm/min by modifying the resin mixture. Though the production speeds are below the industrial standards, economic production scale could be still reached.
Sandwich Elements from Renewable Resources as a Structural Component in the Architecture
Authors: Krombholz Andreas , Werner Peter , Weber Andreas
Published: July 2015

The necessary thermal insulation for buildings was provided for years optimally by polymer foams. Generally the foam is based on petrochemical resources. It is used for external wall insulation and not employed for additional functions. A Sandwich build of rigid laminates and a quite shear resistant polymer foam core results in an extraordinary stiff element. This provides thermal insulation and forms an independent load carrying structure. The sustainability of the sandwich structure can be raised by combining materials from renewable resources. The sandwich system currently developed, in cooperation with our partner from industries C3 Technologies, consists of lignin based foams of varying density and natural fibre reinforced laminates. The lignin is produced from beech-wood via the organosolv-process. Afterwards it is chemically integrated into the phenolic resin. The proportion of lignin in the resin can be varied from 10% up to 40%. This poses a quite prospective idea since using lignin means using nature’s own synthesis instead of artificial petrochemical processes for resin production and thus reducing the energy needed for resin production
Damage Behaviour of Fibre Reinforced Materials Induced by High Temperature Oxidation for Optimisation of Thermal Recycling Routes
Authors: Manis Frank , Wölling Jakob , Drechsler Klaus
Published: July 2015

This study summarizes different characterisation methods performed with new carbon fibres(vCF - virgin carbon fibres) for structural applications as carbon fiber reinforced plastic (CFRP)as well as fiber samples which have been treated under different conditions. These parameters consistof combinations of temperature (400-600 C) and dwell time (30 - 60 min) in an oxidising atmospherein order to provide a fundamental basis for the definition of possible recycling processes to regain thehigh value raw material, i.e. the carbon fibre, after the use-phase of the initial CFRP-structure. The investigationsthat were performed on vCF and secondary fibres (rCF - recycled CF) show in very goodagreement, that below 500 C almost no degradation of the fibre is visible, between 500 and 600 C arapid decrease in different physical and mechanical properties occurs and above 600 C a recovery ofthe fiber in terms of a secondary use in high performance structural context seems not to be feasible.The investigations that were performed consist of optical microscopy for the measurement of the fibrediameter, the deformation of the cross section and a statistical analysis. The second method appliedwas the characterization of the monofilament density, alongside to the breaking force and elongation,leading to the calculation of tensile strength and Youngs Modulus and further statistical analysis ofWeibull Modulus and its decrease over temperature.
Interpenetrating Freeze Cast Composites: Correlation between Structural and Mechanical Characteristics
Authors: Merzkirch Matthias , Pinter Pascal , Dietrich Stefan , Weidenmann Kay André
Published: July 2015

Ceramic freeze cast preforms based on alumina show an anisotropic behavior due to directional freezing during preform production. Beside the specific characteristics such as alumina content and lamellae spacing also the distribution of the so-called domains – regions with a relatively homogeneous orientation of alumina lamellae – play an important role considering stiffness and strength. The gas pressure infiltration process was used for infiltrating the freeze cast preforms with a eutectic aluminum/silicon alloy with a low melting point. Selected regions taken from the freeze cast preform have been analyzed via X-ray micro computed tomography (µCT) prior to the infiltration due to a higher contrast in comparison to the infiltrated preforms. The orientation of the lamellae has been determined from the three dimensional data with an algorithm which is based on the structure tensor. The mechanical stability - in terms of the strength - of the infiltrated preforms has been quantified via quasi static compression tests on cuboid samples. The results show a good agreement between the orientation of the lamellae distribution and the maximum strength of the preform which could also be verified using an analytical model.
Powder Metallurgical Tungsten Fiber-Reinforced Tungsten
Authors: Jasper Bruno , Coenen Jan W. , Riesch Johann , Höschen Till , Bram Martin , Linsmeier Christian
Published: July 2015

The composite material tungsten fiber-reinforced tungsten (Wf/W) addresses the brittleness of tungsten by extrinsic toughening through introduction of energy dissipation mechanisms. These mechanisms allow the release of stress peaks and thus improve the materials resistance against crack growth. Wf/W samples produced via chemical vapor infiltration (CVI) indeed show higher toughness in mechanical tests than pure tungsten. By utilizing powder metallurgy (PM) one could benefit from available industrialized approaches for composite production and alloying routes. In this contribution the PM method of hot isostatic pressing (HIP) is used to produce Wf/W samples. A variety of measurements were conducted to verify the operation of the expected toughening mechanisms in HIP Wf/W composites. The interface debonding behavior was investigated in push-out tests. In addition, the mechanical properties of the matrix were investigated, in order to deepen the understanding of the complex interaction between the sample preparation and the resulting mechanical properties of the composite material. First HIP Wf/W single-fiber samples feature a compact matrix with densities of more than 99% of the theoretical density of tungsten. Scanning electron microscopy (SEM) analysis further demonstrates an intact interface with indentations of powder particles at the interface-matrix boundary. First push-out tests indicate that the interface was damaged by HIPing.
Spark Plasma Sintering and Strength Behavior under Compressive Loading of Mg-PSZ/Al2O3-TRIP-Steel Composites
Authors: Krüger Lutz , Grützner Steffen , Decker Sabine , Schneider Ines
Published: July 2015

Composite materials, which consist of a metastable austenitic TRIP-steel matrix (CrMnNi TRIPsteel; TRansformation Induced Plasticity) reinforced by alumina particles (25 vol.% ceramic, designated as AT 25/75) and reinforced by alumina and MgO partially stabilized zirconia particles (Mg-PSZ) (35 vol.% ceramic, designated as AT 25/75 + MgPSZ) were synthesized through spark plasma sintering (SPS). In the AT 25/75 + MgPSZ, the steel particles were mainly surrounded by alumina. Hence, mostly steel/alumina and alumina/MgPSZ interfaces existed. The mechanical behavior of the as-sintered samples was characterized by compression tests at room temperature and 40 °C and in a range of strain rates between 103s-1and 103s1. The influence of the ceramic content, strain rate and temperature on TRIP-effect of the steel matrix was investigated. Due to the increasing ceramic volume fraction, AT 25/75 + MgPSZ exhibits the highest compressive yield strength under all loading conditions and no strain rate sensitivity. This composite showed no measurable TRIP-effect, due to the low fracture strain. The deformation-induced α’martensite within the steel particles in pure steel and AT 25/75 primary depends on the testing temperature and the strain rate. This is attributed to an increase of stacking fault energy with rising temperature. High strain rates cause adiabatic heating, counteracting the martensitic transformation.
The Evaluation of Thermoplastic Precursors for C/C-SiC Manufactured by Liquid Silicon Infiltration (LSI)
Authors: Reichert Florian , Langhof Nico , Krenkel Walter
Published: July 2015

C/C-SiC composites, fabricated by the Liquid Silicon Infiltration process (LSI), typically use phenolic resin-based thermosets as carbon precursors. In contrast to this, two different thermoplastics (Polyetheretherketone PEEK and Polyetherimide PEI) were examined for their suitability as carbon precursors for C/C-SiC composites. The carbon fiber surfaces were pretreated between 400 °C and 800 °C in nitrogen atmosphere to modify the fiber/matrix bonding. The microstructures of the materials show an increasing SiC content with increasing fiber pretreatment temperature. The flexural strength of the resulting material was determined by 4-point-bending tests.
Investigation of Different Phenolic Resins and their Behavior during Pyrolysis to Form SiC/C-Composites
Authors: Wöckel Lydia , Ebert Thomas , Mainzer Bernd , Frieß Martin , Koch Dietmar , Roder Kristina , Wett Daniel , Nestler Daisy , Wagner Guntram , Spange Stefan
Published: July 2015

Specific phenolic resin samples have been developed as the carbon precursor for SiC/C composites. Liquid phenolic resins suitable for fiber-infiltration in the resin transfer moulding (RTM) process are synthesized by using versatile combination of the aromatic component (phenol, naphthalen-2-ol) with various formaldehyde equivalents such as methanal, 1,3,5,7tetraazatricyclo [3.3.1.13,7] decane (urotropine), and 1,3,5-trioxane, under different reaction conditions. Room temperature liquid resoles (RTLR) are obtained by using an excess of the formaldehyde component over phenol (≥2) under basic conditions. Upon heating RTLR can form a crosslinked network even without addition of a hardening reagent. In addition, novolacs are synthesized under acidic conditions using a phenol/formaldehyde ratio ≥1. Nitrogen-containing resins contain nitrogen due to reaction of phenol with urotropine. Novolacs and nitrogen-containing resins are solids at room temperature and not self-curing. To infiltrate these both resins into SiC fibers in the RTM process, they are dissolved in 2furanmethanol (furfuryl alcohol FA) and urotropine which is added as curing-agent. Both, the molecular weight and the amount of the dissolved phenolic resin have an influence on the viscosity and the carbon yield after pyrolysis which is important for this application. The aim was to create different phenolic resins for the fabrication in the RTM process and to characterize the carbon after pyrolysis with respect to the structure and porosity as these are key parameters to generate a stoichiometric SiC matrix by LSI.
Influence of Specimen Geometry and Surface Quality on the Bending Strength of Short Fiber-Reinforced C/SiC
Authors: Shi Yuan , Koch Dietmar , Hausherr Jan Marcel , Neubrand Achim
Published: July 2015

For continuous fiber-reinforced ceramic matrix composites, there is an extensive knowledge of the influence of specimen geometry on the failure mode and the determined strength in bending tests. In contrast, there are almost no studies on this topic for short-fiber-reinforced CMC, and as a consequence no testing standard for bending tests for such materials exists. In the present work, the influence of the specimen cross-section and the span width on the calculated mean and variance of the bending strength of different short fiber CMC (C/SiC with 3 mm and 10 mm fiber length) were examined. Below a certain specimen cross-section a decrease of the determined bending strength was observed. The relationships between the orientation of fiber bundles in the loaded area of the bending sample, the region of failure initiation and measured failure stress was investigated by high resolution X-ray CT in order to obtain further insight into the causes of strength scatter in these materials. The effect of different surface qualities prepared by grinding and milling on the measured bending strength in short fiber C/SiC was found to be negligible.
Development of a SiNx-Based Barrier Coating for SiC Fibres
Authors: Roder Kristina , Nestler Daisy , Wett Daniel , Mainzer Bernd , Frieß Martin , Wöckel Lydia , Ebert Thomas , Wagner Guntram , Koch Dietmar , Spange Stefan
Published: July 2015

Uncoated SiC fibres in SiC/SiC composites manufactured by the liquid-silicon infiltration (LSI) process show a strong degradation as a result of silicon attack. The goal of this research is the development of a SiNx-based fibre coating, which acts as a barrier against the liquid silicon. The coating is applied by means of low-pressure chemical vapour deposition (LPCVD) utilising the gaseous precursors silane (SiH4) and ammonia (NH3) on a commercial SiC multifilament yarn. The result is an amorphous fibre coating with an increasing coating thickness and a variable chemical composition from the middle of the yarn to the edges. The coated fibres exhibit a reduced characteristic Weibull strength in comparison to the uncoated fibres. In order to examine the stability of the films, the coated fibres undergo a heat treatment at 1450 °C in different environments (vacuum, argon and nitrogen). In all environments, the amorphous SiNxcoatings crystallise to the trigonal Si3N4. Depending on the coating thickness cracks and defects develop. However, the best results and the lowest amount of damaging occurs during the treatment in nitrogen.
Damage Evaluation of CMCs after Drilling with Geometrically Defined Cutting Edges
Authors: Rösiger Achim , Goller Ralf
Published: July 2015

In this contribution a new method of drilling Ceramic Matrix Composites (CMC) with geometrically defined cutting edges is introduced. For this, tools with massive PCD (Poly Crystalline Diamond) drilling bits are applied. To evaluate the drill hole quality the damage behavior is analyzed by an optical method and a new quality index is introduced. The fundamental investigations on the basic drilling parameters of a C/C-SiC material are presented
Adhesive Bonding of Oxide Ceramics for Complex Ceramic Parts in High Temperature Furnaces
Authors: Gadelmeier Christian , Schmidt Jens , Jovanovic Dorde , Zietkowski Marek , Eckardt Christian , Gorywoda Marek
Published: July 2015

Within the scope of the project ENERTHERM: Energy efficiency of thermal processes which is funded by the Bavarian Ministry of Economy (BMWi) components and systems for high-temperature are being developed. Monolithic oxide ceramics (mullite, Al2O3) and oxide-fiber reinforced ceramics (O-CMC) show a high potential for high temperature (HT) applications. Additionally, the demand for complex HT-components such as HT-fanwheels for kilns, supporting HT-lightweight structures or hot gas liners increases. In according to the required component design, joining techniques are needed in order to realize such complex geometries. The generated joints were made by using commercial glass solder from the type Al2O3-SiO2-MgO. For realizing the joining process sintering-joining in HT-kilns was used because of the homogeneous temperature distribution. A CO2 laser (wavelength of 10.6 microns and a power of 1.5 kW) was used for rapid joining process. The mechanical properties were determined in according to DIN EN 843-1 and DIN EN 658-3 (4-point bending strength) and evaluated according to Weibull distribution.
„Smart Multi Material Joint" – Hybrid Joint of Steel and FRP
Authors: Lotte Jens , Reisgen Uwe , Schiebahn Alexander
Published: July 2015

Fiber-reinforced plastics (FRP) are increasingly used in modern industry. They offer numerous advantages in comparison to traditional materials. However, they cannot meet all requirements, which is why it is necessary to join FRP to a metallic base structure in most cases. Existing joining techniques cannot fulfill the demands of a fiber-fair joining technique that does not damage the fibers and can transfer applied forces into underlying laminate layers on the one hand but also provides a ductile failure behavior that is detectable with an integrated sensor on the other hand. An innovative, modified arc welding process offers a way to create small-scale pin structures that work as micro shear connectors without damaging the fibers of the composite, but ensure a multi-step failure behavior. This particular failure behavior enables the use of an integrated sensor system, which monitors the joint.