bluuebunny/crossref_metadata_2025 huggingface dataset:
Biosorption of Nickel by Elaeis guineensis Fruit Fiber
Authors: Nor-Azemi Siti Nor Izuera , Fuadi Farah Aimi , Syed-Hassan Syed Shatir A.
Published: July 2015

The objective of this study is to investigate the ability of Elaeis guineensis fruit fiber or known as oil palm mesocarp fiber (OPMF) to adsorb nickel from aqueous solution. As one of the major oil palm producer, Malaysia has abundantly oil palm waste that potentially be used as biosorbent. Limited studies used OPMF as biosorbent to remove nickel, thus it was used in this study. The effects of pH, initial metal concentration and contact time on nickel uptake were studied. The OPMF was soaked in nickel nitrate aqueous solution and the Ni-loaded OPMF being digested to analyse the nickel concentration by using ICP-OES. The adsorption was investigated in the pH range of 2.0-8.0 and the optimum pH for nickel removal was found to be 7.0. The contact time was varied between 5 to 120 mins and the nickel adsorption was found to achieve equilibrium in a very short time (i.e.<5 mins). The percentage of nickel removal decreased from 3.3 to 1.7 % with increasing nickel concentration from 505 to 1683 mg/L. The adsorption isotherm was fitted well using Langmuir model with correlation coefficient, R2 of 0.98. The kinetic studies showed that the pseudo-second order model is the best model with the correlation coefficients of > 0.99 for all concentrations. Overall, the adsorption of nickel by OPMF gave positive results and the used of OPMF as biosorbent has great potential to be applied in the future.
Characterization and Identification of Isolated Microorganism from Agricultural Soil for Degradation of Cellulose Based Waste
Authors: Abdullah Nur Syazrin Amalina , Abdul Manaf Shareena Fairuz , Ab Aziz Nur Shahidah , Hamzah Fazlena , Idris Norazlina
Published: July 2015

Paper wastes accumulating in the environment are posing an ever increasing ecological threat. This study aimed to isolate soil bacteria closely associated with the bacteria degrading waste paper. A total of six soil samples were collected from dumped soil hostel garden at Universiti Teknologi MARA, Shah Alam. Bacillus, Aspergillus and Micrococcus species were found to be the most widely distributed on the entire sample taken. Six cultures were screened for the ability to degrade cellulose. Bacillus was identified as only bacteria isolated that can degrade paper at highest production of glucose compared to others. The efficacy of microbes in the degradation of paper was analyzed in broth culture fermentation within 7 days incubation. This work reveals that Bacillus subtilis,Bacillus spp and Micrococcus spp posses great potential to degrade paper. In contrast, Acinetobacter spp react very slowly in degrading the waste.
Characterization of Automotive Paint Sludge (APS) for Chemical/Energy Recovery via Microwave Assisted Pyrolysis
Authors: Januri Zakiuddin , Rahman Norazah Bt Abdul , Idris Siti Shawalliah , Matali Sharmeela , Abdul Manaf Shareena Fairuz
Published: July 2015

This paper reported on the characterization of the Automotive Paint Sludge (APS) via several characterisation technique. It is an essential to search the physical and chemical characterization of the automotive paint sludge sample for further microwave assisted pyrolysis experiment for chemical and energy recovery from APS. APS contains about 2.9%, 2.4%, 75.9% and 3.2% of ash, moisture, volatile matter and fixed carbon content respectively. Both wet and dried APS samples show similar FTIR peak at the hydrocarbon region while wet sample have high water content. Meanwhile zero moisture (ZM) sample loss almost 90% of its content on the hydrocarbon. This shows that wet automotive paint sludge samples can be used in the microwave pyrolyzer without any pretreatment and the water can act as an absorbance to microwave radiation. While APS itself contains about 22.6 MJkg-1 of energy. Furthermore, melting temperature of automotive paint sludge are in the range of 260 °C to 500 °C with the enthalpy in the range of 40 J/g to 300 J/g. Chemical composition of APS for all three conditions can be described as C38H10N9S, C102H9N21S and C85H8N21S for wet sample, open air dry sample and zero moisture sample respectively.
Comparative Study on Adsorption of Pb(II) Ions by Alginate Beads and Mangrove-Alginate Composite Beads
Authors: Abas Siti Nur Aeisyah , Ismail Mohd Halim Shah , Siajam Shamsul Izhar , Kamal Mohd  Lias
Published: July 2015

The aim of the present study report on the adsorption performance of alginate bead (AB) and mangrove-alginate composite bead (MACB) bead adsorbents for the removal of Pb(II) ions from aqueous solution. The effects of pH and initial concentration with contact time on the adsorption properties of Pb(II) onto both adsorbent were investigated and were described by isotherm and kinetic studies. The isotherm adsorption data were fitted well to Freundlich isotherms for both beads and the maximum adsorption capacities of the AB and MACB beads were 29.02 mg g-1 and 10.84 mg g-1, respectively. The kinetics adsorption data were best described to a pseudo-second-order kinetic models showing that the MACB beads had a higher kinetic adsorption rate at 2.6084 g mg-1 min-1 compared to AB at 0.7043 g mg-1 min-1.
Determination of Compounds inside Inoculated Aquilaria malaccensis Leaves by Soxhlet Extraction
Authors: Ku Hamid Ku Halim , Mustafar Nur Suhada , Yusof Pazilah Mohd , Mohammad Shawal Siti Sofia , Musa Mohibah , Mohd Rodhi Miradatul Najwa
Published: July 2015

Aquilaria is a special tree that has been awarded to the earth. Aquilaria spp. which belongs to the family Thymelaeceae is one of the most precious trees is the world. Agarwood or gaharu is the name of the resin produced by Aquilaria spp. Historically, agarwood has widely been used as medicine. It was also being used for perfumes, incense and religious purposes in Muslim, Buddhist, Hindu, Christian, and Jewish societies. In order to discover the new uses of the agarwood, knowledge of the chemical constituents inside the plant need to be known. Aquilaria spp tree can be divided into two parts which is bark and leaves. Recently, several studies have been conducted to examine the chemical composition found in Aquilaria spp tree. However, there is still no specific detail documentation on the chemical compounds present in Aquilaria leaves. In this study, Soxhlet extraction method has been used to withdraw the compounds from the leaves. From the results obtained, it shows that extraction of compounds by using methanol was more effective. This was due to the higher polarity inside the methanol. Other than solvents, the samples preparation also gave an effect towards the final results. There were two different types of samples that have been used for this study which are fresh and dried A. malaccensis leaves. The obtaining results showed that more compounds have been extracted from the dried sample. It can be conclude that moisture content in the sample also plays a role in identification of compounds inside the A. malccensis leaves
A Potential Hybrid TiO2 in Photocatalytic Seawater Desalination
Authors: Isha Ruzinah , Abd Majid Nurul Hariyah
Published: July 2015

Titanium dioxide (TiO2) is excellently used in various applications including wastewater treatment. It is known to have superb pigmentary properties, high adsorption in the ultraviolet (UV) region, and high stability. The objective of this paper is to study the effect of contact time of seawater desalination in the photocatalytic reaction. The hybrid TiO2 catalysts; a mixture of TiO2 and biomass ash, was synthesized via wet impregnation and calcined at 800 °C. The photocatalyst was then characterized by using Scanning Electron Microscopy (SEM) and Braunauer-Emmett-Teller (BET). The investigation was carried out in a photoreactor equipped with UV light operated for up to six hours with catalyst to seawater weight ratio of 1:400 and stirring speed of 600 rpm. The salt concentration, turbidity and pH of the water were determined prior and after the investigation. The result indicates that the salt concentration gradually decreased more than 25% as the contact time increased up to six hours. However, there is no significant change on pH value of the water. It can be concluded that the hybrid TiO2 is able to reduce the seawater salinity effectively.
Effect of Voltage towards Bubble Formation on Stainless Steel in Aqueous Suspension during Electrophoretic Deposition
Authors: Abdol Aziz Rabiatul Adawiyah , Abu Bakar N.F. , Mohd Shaufi E.R. , Samsuri N.H.A.
Published: July 2015

The formations of bubble in the polystyrene latex (PSL) aqueous suspension were observed through out the electrophoretic deposition (EPD) process. The voltages in between of 20V to 50V were studied as a parameter for this study to investigate reason of bad quality of deposition when high voltage is applied in the EPD process. The objectives of the study are to observe the pattern and to determine of bubbles formation size on the stainless steel during pulse EPD process. The PSL suspension from pH 5 to 10 were prepared. The bubble formation was observed and size of bubbles was measured by using microscopic video. The difference voltages are applied on the suspension to observe the best condition with no or low bubbles formation when voltage applied. From the experiment, when the voltages increase, the number of bubbles increases. Observation shown that at low voltage the bubble tend to grow up and then burst during the process. As an addition, the sizes of bubbles decrease in base suspension though its increase in acid suspension.
Monitoring of Chemical Speciation of DEA – CO2 – Water System by Raman Spectroscopy
Authors: Shahid Muhammad Zubair , Suleman Humbul , Maulud Adulhalim Shah , Khalil Mohammad Azmi Bustam , Man Zakaria
Published: July 2015

Carbon dioxide separation has gained immense importance since its detrimental effects towards our environment has been realized. Commercially, CO2 has been captured by absorption in alkanolamines such as diethanolamine (DEA), since many years. The thermodynamics and kinetics of the process is a key factor towards its efficiency and significantly depends on its qualitative and quantitative speciation. In this work, the analysis of speciation for CO2 loaded aqueous DEA has been performed by Raman spectroscopy. Experimentally determined CO2 loading data and modified Kent Eisenberg equation was used to quantify the chemical species present. The speciation results were fitted with the respective characteristic Raman peaks of (CO3-, HCO3-, DEACOO-, DEA, DEA+, CO2) by Principal Component Regression (PCR). The fitted results showed good agreement with thermodynamically predicted chemical species.
Flow Injection Analysis Nitrite Sensor Based on Reduced Graphene Oxide Modified Electrode
Authors: Zainudin Nurulasma , Yusoff Mashitah Mohd , Chong Kwok Feng
Published: July 2015

Nitrite is one of the most frequently measured analytes in the environmental analysis due to its detrimental effect on the environment. The development of simple and sensitive analytical method for the detection of nitrite is highly important. In this study, we report the fabrication and testing of nitrite sensor based on the flow injection analysis by reduced graphene oxide modified electrode. The modified electrode exhibits enhanced electro oxidation behavior towards nitrite oxidation. The proposed method has advantages of high precision, lower sample consumption, lower reagent consumption, less dispersion of the sample as well as higher sensitivity.
Solubility of Carbamazepine-Succinic Co-Crystal in Ethanolic Solvent System
Authors: Ramle Noor Ashila , Abd Rahim Syarifah , El-Hadad Omar , Anuar Nornizar
Published: July 2015

Solubility of carbamazepine co-crystal produced from cooling co-crystallization process with succinic acid as a co-crystal former is investigated in this study. Two techniques were used to determine the solubility of the co-crystal which are gravimetry and HPLC. The solubility experiments in ethanol solvent systems were conducted at 6 different temperatures (25, 30, 35, 40, 45 and 50 °C) while for succinic acid ethanolic solution system were conducted at 5 different concentration ratios. Both of the systems are equilibrated for 72 hours. Result from the experiments has shown that the solubility of co-crystal is temperature dependent. As the temperature increases, the solubility of co-crystal also increases; this agrees with the Second Law of Thermodynamic which states that heat facilitates the dissolution process by providing more energy to the system.
Synthesis and Characterization of Cassava Starch Nanocrystals by Hydrolysis Method
Authors: Md Shahrodin Nur Shazrynda , Rahmat Abdul Razak , Arsad Agus
Published: July 2015

Cassava starch nanocrystals (CSN) has not been reported in open literature, although other starches such as rice, corn, potato and bean were widely used as the main material. Thus, the objective of this research was to investigate the possibility of synthesizing high yield of CSN at different concentration of sulphuric acid (H2SO4). The physical and chemical properties of synthesize CSN was also investigated. Synthesized CSN was prepared by hydrolysing native cassava starch (NCS) with several concentration of H2SO4 (2.8 M, 3.0 M, 3.2 M and 3.4 M). The acid hydrolysis process took five days with continuous stirring speed of 300 to 400 rpm, with constant temperature of 37 °C. The hydrolysed solution of CSN underwent centrifuging process with distilled water until neutral to make sure that no acid residues remain in the CSN solution. The CSN precipitate was dried in an oven over night at 60 °C. The highest yield (1.1 %) produced was from 3.4 M CSN. Morphology test by Transmission Electron Microscopy indicated that the samples have been destructed and degraded to be nanocrystals with a size range of 5 - 20 nm. X-ray Diffraction (XRD) and 13C Nuclear Magnetic Resonance (NMR) were used to indicate the type of crystallinity for both NCS and CSN.
Tar Elimination from Producer Gas by Using In Situ Catalytic Reforming of Tar
Authors: Malek Nur Hanina , Asadullah Mohammad , Sauki Arina
Published: July 2015

Tar removal from producer gas was investigated using activated carbon supported iron catalyst. Activated carbon was derived from jute stick biomass. The catalyst surface areas and pore volume were characterized by using iodiometric titration which shows that as the iron loading percentage increased, the adsorption capability was also increased which represents the increment of pore volume of the catalyst. Based on XRD pattern, the iron species formed on the activated carbon surface is mostly amorphous magnetite (Fe3O4) species coexisted with the reduced irons (α-Fe and γ-Fe). The reduced iron on catalyst surface justify the active phase which enhances the tar reforming during biomass gasification.
Total Phenolic Content and Antioxidant Activity of Local Fruit Wastes in Malaysia
Authors: Ibrahim Ummi Kalthum , Yusof Muhammad Ihsan Sobri , Zamil Khairul Anuar Ahmad , Kamarrudin Nadia , Maqsood-Ul-Haque Siti Noor Suzila , Ab Rashid Siti Rafidah
Published: July 2015

The purpose of this study is to investigate the antioxidant properties and total phenolic content in local fruit wastes. Watermelon rinds, mango and banana peels were selected in the experiment. Two parameters involved were the extraction time and temperature. All samples had undergone drying process in an oven at 40°C for 24 hours before being extracted with 80%, v/v methanol on a hot plate together with magnetic stirrer. The extraction time was ranged from 20 to 40 minutes and the extraction temperature was from 30 to 60°C. Ferric Reducing Antioxidant Power (FRAP) assay and Folin-Ciocalteu reagent were used for antioxidant analysis and phenolic content determination, respectively. UV-Vis spectrophotometer was used to detect the antioxidant activity at 593 nm and 765 nm for phenolic content. Response Surface Method was used to find the best extraction condition. The best extraction conditions were found at extraction temperature and time of 58.93°C and 37.86 minutes, respectively.
Fabrication of Organic and Inorganic-Based Nanowires: An Overview
Authors: Mohamed Jaafar Muhammad Izzuddin , Hashim Md Amin
Published: July 2015

The real application of nanofabrication is in the nanoindustries due to their existence in nanodimensions. In this paper, it is attempted to review on the fabrication techniques of organic and inorganic nanowires, which includes vapour and solution processes. The two commonly approached methods, with respect to solution processes are fabrication through template-assisted electrodeposition technique, and the vapour-liquid-solid (VLS) as compared to organic nanowires which are fabricated through vapour and solution processes.
Synthesis of Hydroxyapatite via Sol-Gel Dip-Coating Method on Ceramic Support
Authors: Ibrahim Norliza , Zaiton Rafizah , Askalani Mohd Akmal
Published: July 2015

Hydroxyapatite (HA) has been used extensively in application of biomedical either in the form of porous ceramics, dense ceramics, powders or granules for gap filling or coatings for implants. Synthetic HA also has an excellent ion exchange properties that used as a filling material for chromatography columns. Furthermore, many researchers have reported that high removal efficiency of the heavy metals can be achieved by using synthetic HA. In this study, HA was synthesized via sol-gel method by using calcium nitrate tetrahydrate and triethyl phosphate as the precursors and 2-metoxiethanol ether as an organic solvent. Then, HA sol was deposited on silica-alumina based ceramics whose made by recycled sanitary ware waste by dip-coating method. The obtained coated substrates were then dried at 150°C and subsequently subjected to calcination up to 1000°C. Fourier Transform Infrared (FTIR) characterization for the HA powders dried at 150°C and calcined at 600°C, 800°C and 1000°C were carried out to come out with the spectral characteristic indicative of chemical bonding. High Purity of the obtained hydroxyapatite was confirmed by XRD analysis. The SEM micrographs displayed the microstructure of the HA coatings.
Interfacial Tension Dependence on Nanoparticle Surface Modification for Stabilization of CO2 Foam in EOR: An Overview
Authors: Mohd T.A.T. , Harun Azwan , Ghazali Nurul Aimi , Alias N. , Yahya Effah
Published: July 2015

Foam Flooding have been suggested to replace gas injection in Enhanced Oil Recovery (EOR) method since it will improve the volumetric sweep efficiency due to its low mobility. This paper aims to review on the relationship of Interfacial Tension (IFT) of the CO2 foams and nanoparticle surface modification. Generally, in foam flooding technique, surfactant is used to stabilize the CO2 foams. However, the concern about the stability of the surfactant-stabilized CO2 foam has been rising due to high surfactant adsorption on the rock surface and they also tend to degrade at high temperature. Hence, nanoparticle has been introduced to generate more stable CO2 foam by adsorption of nanoparticles at the fluid-fluid interface. Based on the review, the stability of CO2 foam generated by nanoparticles is due to the strong adhesion energy at the fluid-fluid interface where the interfacial tension between aqueous phase and CO2 gas phase inside the foam is one of the key parameter. It also has been identified that the main factors that influenced the interfacial tension at the fluid-fluid interface are the nanoparticles concentration and the degree of hydrophilicity of nanoparticles. The correct amount of nanosolid particles present at the fluid-fluid interface and the optimum degree of hydrophilicity with favorable contact angles less than 90 degree will increase the interfacial tension that lead to increase in adhesion energy and high stability foam can be generated.
Simulation of Oxygen-Steam Gasification for Hydrogen Production from Date Pits
Authors: Al-Ghamdi Ahmed A , Inayat Abrar
Published: July 2015

The need to find a renewable and sustainable energy has transformed into a demand due to the depletion of fossil fuel, and more importantly, the greenhouse gasses concerns. Hydrogen is a one of the clean and sustainable energy source. In addition, hydrogen used as raw material in industries, such as fertilizer plant, refinery and methanol production plant. Hydrogen has the potential as a clean energy carrier and the date pits availability in Saudi Arabia, the gasification of date pits is proposed. This work focused on developing a flowsheet to evaluate the feasibility of producing hydrogen from the gasification of date pits via a simulation work in Aspen Hysys. Using the simulation model, a study has been made to investigate the effects of temperature and steam/biomass ratio on the product gas, hydrogen yield and carbon conversion. The model has been also validated with literature and showed good agreement. The favorable temperature of the gasifier for high hydrogen yield is predicted to be in the range of 845-910°C. Based on the results, at temperature is 850°C and steam/biomass ratio of 0.8, maximum conversion and hydrogen yield achieved.
Online Gas Chromatography of Hydrogen and Methane Production from Palm Oil Mill Effleunt (POME) Using High Frequency Ultrasonic Atomization: A Preliminary Study
Authors: Abd Rahman Siti Raihanah , Ku Hamid Ku Halim , Alias Rusmi , Abd Wahid Nazifah
Published: July 2015

This study aims to directly analyze the production of hydrogen and methane gas from POME via high frequency ultrasonication atomization. The advantage of the currently common process was studied in regards to the application of low frequency ultrasonic pretreatment prior to biological processes; anaerobic digestion and fermentation for the production of methane and hydrogen gases respectively. Existing ultrasonic application is limited to sludge disintegration, reducing chemical oxygen demand (COD) values and total solid, while subsequent biological processes take several days to produce gases. However, in this study, high frequency (2.4 MHz) ultrasonic atomization process was able to produce methane and hydrogen gases directly without any biological process. These gases were detected by using an online gas chromatography. The results from the ultrasonication process show that the production gases are consisted majorly of hydrogen compared to methane. Thus, high frequency ultrasonication process can be considered as an alternative method in rapid production of methane and hydrogen gases.
Aspen Plus Simulation of Ultrasound Assisted Distillation for Separating Azeotropic Mixture
Authors: Mahdi Taha , Ahmad Arshad , Ripin Adnan , Nasef Mohamed Mahmoud , Oladokun Olagoke
Published: July 2015

Earlier works have proved the potentials of altering the vapor liquid equilibrium of azeotropic mixture by sonication phenomena. In this work a mathematical model of a single stage vapor-liquid equilibrium system developed in Aspen Custom Modeler is exported to Aspen Plus to represent one stage of ultrasonic flash distillation (USF). The USF modules are connected serially to mimic a distillation process. As a case study, the separation of ethanol-ethyl acetate mixture is considered. The final targeted composition of 99 mole % of ethyl acetate was achieved when 27 USF modules were used despite the fact that the mixture form azeotrope at 55 mole % ethyl acetate. The results reinforced the anticipated potentials of sonication phenomena in intensifying distillation process to overcome azeotropes, and provide useful insights for the development of a pilot-scaled facility that is currently under development.
Low Velocity Impact of Aluminium Foam - Glass Fibre Reinforced Plastic Sandwich Panels
Authors: Ismail Mohd Fadzli , Jumahat Aidah , Ahmad Nurulnatisya , Ismail Muhammad Hussain
Published: July 2015

Sandwich structures with metal foams core are widely used in various engineering applications due to their special properties of high-strength and high-stiffness to weight ratio when compared to the properties of pure material systems. Sandwich structures have the capability to resist impact loads which make them favorable for energy absorber application. The aim of this research is to investigate the impact properties of aluminium foam sandwiched with glass fibre reinforced plastic (GFRP). Drop weight impact test was conducted using hemispherical impactor tip at velocity of 6.7 m/s by striking the samples with and without face-sheets. The result showed that the GFRP and aluminium foam core sandwich panel exhibited promising energy absorption properties, corresponding to the highest specific energy absorption value observed.
Application of Response Surface Methodology for Optimization of Methylene Blue Removal by Casuarina equitifolia Leaves Powder
Authors: Mohd Norzila , Wan Osman Wan Hasnidah , Salleh Mohd Shahrul Nizam , Syed Draman Sarifah Fauziah , Abd Kahar Nurul Syahirah , Zulkifli Muhammad Nursalam
Published: July 2015

Dye is a type of colorants that are widely used in many industries. Many dyes are toxic in nature with suspected carcinogenic and mutagenic effects that affect aquatic lives and also human beings. Adsorption process is considered as eco-friendly method to remove color from the aqueous solution compared to other established method. In this study, Casuarina Equitifolia leaves were used as an adsorbent. The Response surface methodology (RSM) was employed, using a central composite design (CCD) to optimize the three important variables, i.e., initial dye concentration, pH of the dye solution and adsorbent dosage in order to remove of methylene blue from aqueous solution. From the analysis of variance (ANOVA), the value (>0.8) of the coefficient of determination (R2) was obtained. The optimal condition was established at pH 6.91, 0.1 g adsorbent dosage and 10ppm initial methylene blue concentration. The removal efficiency was found to be 98.80%. From the findings, it shows that Casuarina Equitifolia leaves powder is suitable to be used as an adsorbent in removal of color from aqueous solution.
Experimental Field Study of Green Tower Setup
Authors: Solihin Zainoor Hailmee , Wisnoe Wirachman
Published: July 2015

A Green Tower for setup a pilot experiment consists of the solar collector and the tower was built. The temperature distribution of the Green Tower was measured and analyzed. The data of the highest experimental temperature inside the Green Tower collector’s reached was 52oC at 1300 hours at solar irradiation received of 623W/m2 respectively, with the ambient temperature at 31 oC. The Green Tower that used solar thermal power and utilizing a combination of solar air collector using the principal of solar oven and central updraft tube to generate a solar induced convective flow, which drives pressure to develop artificial wind. This paper presents the experimental field study and practical experience of the Green Tower. The discussion on temperature distribution and also updraft wind of the Green Tower is described and then the results from the designing, building and experimental are presented. The results and suggestions for the future reference will also be discussed.
Optimal Low Carbon Cement Plant via Co-Processing Measure
Authors: Ishak Siti Aktar , Hashim Haslenda
Published: July 2015

Cement industry is one of the highest contributor in carbon dioxide (CO2) emissions. With that, this paper proposes the development of a systematic optimization model where minimized production cost is anticipated within the CO2 reduction target and fuels mixture. The optimization models consider co-processing measures which replaces parts of carbon rich fuels with lower carbon fuels in order to achieve lower carbon emissions. The proposed models are executed using General Algebraic Modeling System (GAMS). With highest carbon reduction of 3.2%, the minimum manufacturing cost went from €59.748/t clinker for a 0% carbon reduction target to €65.737/t clinker.
Innovative Aluminum Based Metallic Glass Particle Reinforced MMCs Produced by Gas Pressure Infiltration
Authors: Lichtenberg Klaudia , Weidenmann Kay André
Published: July 2015

Over the last years, new alloys were developed to create metallic glasses showing high crystallization temperatures. Such metallic glasses generally can be embedded into other materials when processing temperatures are lower than crystallization temperatures. As recent studies show, feasible crystallization temperatures may exceed the melting point of common metals and fabrication of metallic glass particle reinforced MMCs is now not only possible by powder metallurgical methods but also by processes using melt infiltration. Hence, these metallic glasses offer a high potential for use as reinforcements in a lightweight metal matrix such as aluminum: By incorporation of metallic glass structures into a ductile matrix, it is possible to utilize its outstanding advantages like high strength and elastic strain limit while circumventing its negative properties like brittleness.The particle reinforced composites in this contribution were produced by gas pressure infiltration. This process includes melt infiltration of a particle filled mold using pressurized gas. To keep a sufficient separation between processing temperature and crystallization temperature, the metallic glass Ni60Nb20Ta20 (Tx = 721 °C) and the eutectic aluminum alloy AlSi12 with a low melting point (Tm = 580 °C) as matrix metal were selected for process. After infiltration, the fabricated MMCs were investigated by micro computed tomography (µCT) to analyze the particle distribution within the composite. Furthermore, mechanical tests and elastic analysis using ultrasound spectroscopy were performed to classify its properties.
Gigacycle Fatigue Behaviour of Sintered WC-Co Hardmetals Investigated by Ultrasonic Resonance Testing
Authors: Betzwar Kotas Agnieszka , Weiss Brigitte , Danninger Herbert
Published: July 2015

Hardmetals, manufactured from powders by pressing and sintering, are the most important tool materials in service today. In many applications, such as milling or percussion drilling, they are subjected to fatigue with considerable loading cycle numbers. In the present study, the fatigue behaviour of hardmetals in push-pull loading was investigated up to Nmax= 1010using ultrasonic resonance fatigue testing. It showed that with all hardmetal grades investigated there is no fatigue “limit”, i.e. a horizontal branch of the S-N curve, but a consistent drop of the curve up to maximum N. Crack initiation was found to occur predominantly microstructure-controlled, as compared to defect controlled as typical for powder metallurgy tool steels.Keywords: gigacycle fatigue, WC-Co hardmetals, ultrasonic fatigue testing, fatigue limit
Processing and Characterization of Wood Plastic Composites from Bio-Based Polyamide 11 and Chemically Modified Beech Fibers
Authors: Zierdt Patrick , Weber Andreas
Published: July 2015

In this study, the reinforcement of bio-based Polyamide 11 (PA 11) with physico-chemically modified Beech Fibers was investigated. In a first step, an improvement of the thermal stability of the fibers was achieved by a two-step alkaline treatment with sodium hydroxide and hydrogen peroxide. This effect was attributed to the removal of the hemicellulose from the fiber surface, as verified by Attenuated Total Reflection Infrared Spectroscopy (ATR-FTIR). Consequently, the onset-temperature of thermal degradation as measured by Thermo-Gravimetric Analysis (TGA) increased from 285 °C to 337 °C. Given this, the compounding of the modified fibers with the low melting bio-based Polyamide 11 was done in a lab-scale co-kneader and followed by subsequent injection molding of test specimens. Analysis of the mechanical and thermo-mechanical properties of the processed Wood Plastic Composites showed a beneficial effect of the chemical fiber treatment on composite stiffness, and allowed for suggestions to improve the up scaling of the processing.
Impact Resistance Bio Compound
Authors: Möhl Claudia , Krombholz Andreas
Published: July 2015

Modified wood fibre reinforced polypropylene composites at a wood fibre content of 50 wt. % are prepared using different types of wood fibres (beech wood refiner fibre, mercerised beech wood refiner fibre, mercerised and bleached beech wood refiner fibre as well as beech wood chips, mercerised beech wood chips, mercerised and bleached beech wood chips) to improve the impact resistance of the final composite. Additionally a beech wood refiner fibre-PP composite as well as a beech wood chip-PP composite are mixed with regenerated cellulosic fibres (5 wt. % and 10 wt. %) to further enhance the impact resistance. To increase the interfacial adhesion with the matrix and to improve the dispersion of particles two different coupling agents with contents from 2 wt. % to 8 wt. % are tested with two wood plastic composites (WPC). One is made of beech wood refiner fibres and the other one is produced from beech wood chips.The present study investigated Charpy impact property of wood fibres reinforced polypropylene as a function of fibre modification, content of regenerated cellulosic fibres and coupling agent.From the results it is observed that beech wood refiner fibre-PP composites show better Charpy impact properties than beech wood chips-PP composites. Charpy impact resistance is improved by mixing regenerated cellulose fibres (RCF) and RCF-PP-granule with beech wood refiner fibres and chips. The maximum increase in impact resistance is two times for refiner fibres and 10 % RCF-PP-granule respectively three and a half times for chips and 10 % RCF-PP-granule. By adding coupling agent Charpy impact resistance is nearly doubled for all wood fibre-PP composites.
Knowledge Based Technologies for Promoting Innovation in Material Science
Authors: Dornhöfer Mareike , Holland Alexander , Fathi Madjid
Published: July 2015

Materials and their properties are nowadays mostly represented either in forms of material data bases or digital data sheets. While these are sources of facts about the particular materials, the interconnection between the different materials, their usage and development is still lacking. Besides, the data bases are mostly distributed, run by different institutions or specialized on only one category like metals or polymers. The given article addresses the application of knowledge management in the area of material science and engineering for gathering, representing and distributing knowledge as well as supporting a sustainable material and product development. Sustainability, green engineering and innovativeness are crucial deciding factors for today’s material development and should therefore be addressed and integrated in the scope of promoting innovation in material science. To accomplish the aforementioned goal, a combination of semantic and case based methods will be applied in a holistic concept, entitled MatProSQI. It is thus become possible to interconnect and reference fact or knowledge of materials, like category, property, test results, production requirements, sustainability factors, user feedback and experiences of former applications. In addition to the representation of knowledge, collaboration between the engineers is detected as an essential factor for a steady transfer of knowledge.
Integration of Mineral Fiber Semi-Finished Products in Bituminous Matrices
Authors: Lindner Marco , Gelbrich Sandra , Kroll Lothar
Published: July 2015

This thesis investigates the development of an innovative fibre reinforced composite. A developed textile, consisting of mineral fibres that is embedded in a special mastic asphalt matrix. The integration of a grid shaped textile structure into the asphalt cause an inner reinforcement of the asphalt layer. This leads to a significant enhancement towards the tensile strength during bending. It also gives resistance to deformation. Rut formation is minimized and the thickness of the asphalt layer can be reduced.
Mechanical Properties of Structural Paper-Polypropylene Composite Laminates
Authors: Prambauer Martina , Paulik Christian , Burgstaller Christoph
Published: July 2015

Natural fiber reinforced polymers have gained increasing interest in research with the aim of replacing conventional reinforcements, such synthetic or glass fibers. In this work, whole paper sheets of copy, filter and newspaper were used for fabricating cellulose fiber reinforced polypropylene composites with MAPP as a coupling agent. By varying the amount and type of paper, the influence of these parameters on the mechanical properties was observed. The laminates were produced by a film hand stacking method and hot pressing. The characterization was carried out by tensile and flexural testing. Remarkable results were obtained for copy and newspaper composites at a fiber content of 30 and 40 vol.-%. In summary, structural paper reinforced composites with attractive mechanical properties were obtained, indicating the high potential of whole paper sheets as polymer reinforcement.
Analysis and Evaluation of Different Influencing Factors in Processing of Hollow and Full Beads by Alginate Gelation Based on Zirconia and TRIP Steel
Authors: Oppelt Marie , Aneziris Christos G.
Published: July 2015

A novel and innovative process for full as well as hollow metal-matrix composite bead fabrication using gel-casting process by alginate gelation is investigated. In particular the influence of four different alginates and various solidifying agents have been investigated regarding the formation and stability of full and hollow beads. The suspension contained a metastable austenitic steel powder (16Cr7Mn3Ni) and zirconia particles as well as different alginates and was added dropwise into water containing different solidifying agents for forming beads. With the aid of sodium and potassium alginate dropped in solution with CaCl2, full metal beads have been obtained. Hollow beads have been produced using potassium alginate and Ca (OH)2 as solidifying agent and show a hollow space fraction of 65%. At lower strains (up to 15 %), all zirconia reinforced full steel beads obtain higher specific energy absorption (SEA) in comparison to pure steel beads.
Efficient Processing of Metal-Matrix-Composites by Combining Direct Pressure Sintering and Subsequent Thixoforging
Authors: Storz Andreas , Schubert Thomas , Weissgärber Thomas , Seyboldt Christoph , Riedmüller Kim Rouven
Published: July 2015

The paper describes a cost effective and innovative combination of direct pressure sintering and subsequent thixoforming to produce MMC-components in (near-) net shape quality and, thus, to make these interesting materials attractive to mass production.First results of some combinations of aluminium matrix alloys with different ceramic reinforcements, consolidated by fast pressure sintering show the efficiency of this technology.The further processing of the consolidated billets has been performed by thixoforging. It can be shown, that the homogeneous microstructure from the direct pressure sintering stage with uniformly distributed ceramic reinforcements can be maintained over the semi-solid state and a full densification can be achieved. Form filling was complete and surface quality was comparable to forgings from conventional alloys.This new process flow shows advantages regarding the material yield in each of the processing steps. The (near-) net shape quality of thixoforged components allows a reduced effort for machining, which is of special importance for composite materials with a high content of wear resistant hard phases like SiC-particles.
Synthesis of Copper/Silicon-Carbide Composites in a Thermodynamic Disequilibrium
Authors: Klement Maren , Nagel Alwin , Lott Oliver
Published: July 2015

Composites with interpenetrating metal-ceramic microstructures (IPC, interpenetrating composites) can be tailored for specific applications, such as high thermal conductivity combined with low thermal expansion, e.g. for heat sinks. Heat sinks are required in power electronic devices or in future fusion reactor technology where extreme conditions and high cyclic thermo-mechanical loads appear. Due to its rigid ceramic backbone IPCs are expected to reveal high thermal stability. Pure silicon carbide exhibits high thermal conductivity, low coefficient of thermal expansion, high corrosion and wear resistance. But it is also known as a very brittle material when mechanical loads are applied. Thus a composite of silicon carbide with ductile and highly conductive copper seems to be a promising new material for a number of applications.This paper reports the synthesis of Cu-SiC composites using a unique high temperature squeeze casting process (HTSC). Microstructural design of SiC-preforms with open porosity and its synthesis progress is reported. Influence of preform properties, temperature, pressure and atmosphere during HTSC were investigated. A qualitative and quantitative description of the microstructure of the composites and their composition allows the creation of structure-property correlations that take effect retroactively to the casting process.
Thermal Conductivity Behaviour of Al/Diamond and Ag/Diamond Composites in the Temperature Range 4 K < T < 293 K
Authors: Edtmaier Christian , Bauer Ernst , Tako Zeze Serge , Segl Jakob
Published: July 2015

Two different systems, the non-reactive Ag–diamond and the reactive Al–diamond system, were assessed by their thermal conductivity behaviour, both were fabricated by gas pressure assisted infiltration of densely packed diamond bulks with aluminium or silver and different Si-concentration and diamonds of varying particle sizes. The effect of Si-concentration on the interface thermal conductance h between Al, Ag and diamonds was investigated in dependence of temperature by measuring thermal conductivity of composites with different sized diamond particles in the temperature range from 4 K up to ambient. Composite thermal conductivities κc(T) can be as high as 860 W m-1 K-1 at roughly 100 K for Al/diamond and 1100 W m-1 K-1 for Ag–Si/diamond at approx. 150 K. Although the Si concentration in the matrix plays an eminent role for κc(T), i.e. the lower the Si concentration, the higher κc(T), interface thermal conductance is almost unaffected in the reactive Al-diamond system. Furthermore, they are close to values determined on clean model systems, i.e. sputtered and evaporated metal layers on diamond monocrystals. For Ag–diamond composites, the matrix composition of Ag–1Si seems to reflect an optimal composition, as the highest thermal conductivity κc(T) and an extraordinary higher interface conductance was achieved compared to Ag–3Si/diamond composites.
The Influence of Stress and Heat on the Transformation Behaviour of NiTi for Actuator Applications in Extruded Aluminium Matrix Composites
Authors: Pinter Pascal , Reeb Andreas , Weidenmann Kay André
Published: July 2015

The integration of functions in lightweight structures features great potential for future applications in diagnosis and control. The combination of shape memory wires or ribbons made of NiTi embedded in aluminium and manufactured by composite extrusion offers the possibility to produce a composite actuator material in a single production step. The extrusion process allows a wide range of shapes and provides higher versatility than actuators made of bi-metals. The transformation temperature of NiTi varies depending on the composition of the alloy, between -100 °C and 100 °C. However, NiTi can also transform stress-induced. In the designated application, a force is applied via the interface onto the matrix material to deform it. Due to the resulting stress, the transformation temperature rises to temperatures higher than those of the unloaded material. Furthermore the production of composite extrusions leads to a significant heat input on the shape memory alloys followed by another increase of the transformation temperature.Therefore it is essential to reproduce the heat treatment and the stress-induced transformation to predict the transformation temperature in the resulting composite influenced by the interface. For that purpose, the wire gets annealed in a furnace with different durations at a temperature similar to that of the bar extrusion process. After this, the transformation temperatures can be observed at various stresses to evaluate their applicability for aluminium composite actuators.
Development of a Silicon-Infiltrated Silicon Carbide (SiSiC) Friction Layer by the Doctor-Blade Technique Using a Computer-Optimized Calculation for the Packing Density
Authors: Seffern Pascal , Klein Lee , Tischer Daniel , Liersch Antje
Published: July 2015

This paper focuses on an iterative algorithm for setting and attaining particle packing densities by means of different concentrations of a matrix material. The mechanical properties of a product, such as fracture toughness, bending strength and thermal conductivity are directly dependent on the amount of matrix material present. A tape cast friction layer was developed, in order to investigate the dependence of the parameters of the RRSB distribution on concentration of matrix material. The results verify the calculation method of a solid mixture and show a linear dependence of the RRSB particle-parameternon the concentration of matrix material (SiC-content).
Interface Phenomena of Co-Sintered Steel-Zirconia Laminates
Authors: Bergner Anne , Moritz Tassilo , Michaelis Alexander
Published: July 2015

The composite formation of steel and ceramics is especially for medical applications of great interest. By use of the multicomponent tape casting metal-ceramic composite components like bipolar scissors and other surgical instruments can be produced. A coating technology that comes from the paper industry, allows to apply a very thin insulating layer of a few microns between the electrodes consisting of stainless steel. Until now bipolar surgical instruments are produced by mechanical joining of steel and ceramic parts or by spraying a ceramic layer on the steel instruments. This joining steps can lead to stresses in the sensitive ceramic material and leave fine interstices or pores that are not only avoidable with a force and / or tight fit. Both factors are reasons for premature failure of the instrument, even if the materials are not yet at the limits of their resistance. Through the joint shaping by the tape casting and subsequent co-sintering of both materials, a material bond is achieved in addition to the previously existing mechanisms of force and form fit. This optimizes the composite properties and increases the usage time of metal-ceramic layered composites. Special focus is given to the formation of the interface and the associated changes in properties of the individual components of the laminate. These investigantions illustrate the influence of co-manufacturing on the texture of the laminate materials and the formed interface between them. By x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), x-ray fluorescence analysis (RFA) and thermodynamic calculations (FactSage) of the material bond at the metal-ceramic interface is investigated. In various application areas where steel and zirconia should occur as integral partners, this material combination may be established.
Thermophysical Properties of Molybdenum Copper Multilayer Composites for Thermal Management Applications
Authors: Seiss Martin , Mrotzek Tobias , Dreer Norbert , Knabl Wolfram
Published: July 2015

The key properties of materials used for thermal management in electronics are thermal conductivity and the coefficient of thermal expansion. These properties can be tailored by stacking molybdenum and copper layers. Here, molybdenum copper multilayer composites with varying copper content, from 63 to 88 wt%, have been investigated. It is demonstrated, that thermal conductivity and coefficient of thermal expansion, can be adjusted by the copper content. Two flash methods for measuring the thermal conductivity are compared and the validity of the results is discussed since measurements on thin materials with strong anisotropy require a certain setup of the measurement device. For the studied compositions the thermal conductivity was determined to be between 220 to 270 W/m/K and the coefficient of thermal expansion between 6.1 to 11.5 ppm/K.