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Showing papers in "Advanced Materials Research in 2016"


Journal ArticleDOI
TL;DR: In this paper, the authors illustrate the complexity of this process chain with a special focus on the roll-to-roll manufacturing of electrodes and discuss the application of a quality management system in lithium-ion battery production.
Abstract: Lithium-ion batteries are a key technology for energy storage not only in consumer electronics but also in e-mobility and stationary applications. However, in order to guarantee the success of lithium-ion batteries in the long term, improvements related to performance, lifetime and production costs need to be made. Mastery of the highly interlinked process chain in lithium-ion battery manufacturing is a challenge and often acquired on the basis of experience. This paper illustrates the complexity of this process chain with a special focus on the roll-to-roll manufacturing of electrodes and discusses the application of a quality management system in lithium-ion battery production.

46 citations


Journal ArticleDOI
TL;DR: In this paper, the compositional, structural, morphological, thermal and optical properties of nanocrystalline NiO nanoparticles were studied using energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectrographs, and Raman Spectroscopy.
Abstract: Nanocrystalline NiO has been prepared successfully by chemical precipitation route using nickel nitrate hexahydrate (Ni (NO3)2 ·6H2O) and sodium hydroxide (NaOH) aqueous solution at a temperature of 60 C. Their compositional, structural, morphological, thermal and optical properties were studied using energy dispersive analysis of X-rays (EDAX), X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence (PL) spectroscopy and Raman spectroscopy. From XRD pattern we confirmed the face centered cubic (fcc) structure of the synthesized NiO nanoparticles. The selected area electron diffraction (SAED) pattern indicated the same crystalline planes as seen in XRD pattern. TGA indicates good thermal stability of synthesized NiO nanoparticles and the optical absorption spectrum of NiO nanoparticles shows the strong absorption edge at 235nm (4.10eV). PL spectra of NiO nanoparticles shows two wide emission peaks at 420nm (2.95eV) and 440nm (2.82eV) and a strong–broad peak at 460nm (2.70eV) in violet emission band whereas the Raman peak observed at 518cm-1 shows the Ni-O stretching mode of vibration.

41 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present an approach that uses real-time data provided by future cyber-physical systems to integrate scheduling and control and to manage the dynamics of highly flexible manufacturing systems.
Abstract: The increasing customisation of products, which leads to higher numbers of product variants with smaller lot sizes, requires a high flexibility of manufacturing systems. These systems are subject to dynamic influences and need increasing effort for the generation of the production schedules and for the control of the processes. This paper presents an approach that addresses these challenges. First, scheduling is done by coupling an optimisation heuristic with a simulation model to handle complex and stochastic manufacturing systems. Second, the simulation model is continuously adapted by real-time data from the shop floor. If, e.g., a machine breakdown or a rush order appears, the simulation model and consequently the scheduling model is updated and the optimisation heuristic adjusts an existing schedule or generates a new one. This approach uses real-time data provided by future cyber-physical systems to integrate scheduling and control and to manage the dynamics of highly flexible manufacturing systems.

21 citations


Journal ArticleDOI
TL;DR: In this article, LiNibate nanostructured thin films were deposited on (100) N-type Si substrates and spin coating technique was used employed the polymeric precursor method (Pechini process).
Abstract: Lithium niobate nanostructured thin films were deposited on (100) N-type Si substrates. Spin coating technique was used employed the polymeric precursor method (Pechini process) . The prepared films were Annealing in static air and oxygen atmosphere was performed at 500 _C for 2 h. X-ray diffraction analysis and SEM properties was carried out for films prepared at different mol concentration (0.25,0.50,0.75,1.00) Mol%. The results show a good enhancement in both structural and surface morphology of the films with increasing the concentration

21 citations


Journal ArticleDOI
TL;DR: In this paper, the authors focused on the processing of thermoplastic composite materials obtained from carbon fibers (CFs) treated by plasma assisted techniques and found that the treatments increased the CF roughness and caused slight changes in the CF structure.
Abstract: This paper is focused on the processing of thermoplastic composite materials obtained from carbon fibers (CFs) treated by plasma assisted techniques. The treatments employed in this work were the Dielectric Barrier Discharge (DBD), which is done at atmospheric pressure, involving lower energies and the Plasma Immersion Ion Implantation (PIII), which is performed at low pressure, involving higher energies. After the treatments, samples characterizations were performed to determine which treatment is most effective to get better physico-chemical CF surface properties. The techniques employed in this work in order to evaluate the surface treatment were: scanning electron microscopy (SEM); atomic force microscopy (AFM) Raman spectroscopy and x-ray photoelectron spectroscopy (XPS). Treated and untreated CFs/Polyphenylene sulfide (PPS) composites were processed by hot-compression molding technique. These composites were evaluated by interlaminar shear tests (ILSS). After analyzing the results, it was found that the treatments increased the CF roughness and caused slight changes in the CF structure. In addition, there was an increase in the shear strength of the composites obtained from treated fibers by both plasma processes. In conclusion, DBD and PIII treatments are effective tools for improving adhesion between CF and the polymeric matrix.

20 citations


Journal ArticleDOI
TL;DR: In this article, the authors describe new process chain approaches for the manufacturing of intrinsic hybrid composites for lightweight structures based on automated fiber placement, resin transfer molding, deep drawing, rotational molding and integral tube blow molding.
Abstract: This publication describes new process chain approaches for the manufacturing of intrinsic hybrid composites for lightweight structures. The introduced process chains show a variety of different part and sample types, like insert technology for fastening of hollow hybrid shafts and profiles. Another field of research are hybrid laminates with different layers of carbon fiber reinforced plastics stacked with aluminum or steel sheets. The derived process chains base on automated fiber placement, resin transfer molding, deep drawing, rotational molding and integral tube blow molding.

20 citations


Journal ArticleDOI
TL;DR: In this paper, 75Cr3C2-25NiCr coating was applied on T91 boiler tube steel substrate by high velocity oxy-fuel (HVOF) process to enhance high-temperature corrosion resistance.
Abstract: In the present investigation, 75Cr3C2-25NiCr coating was deposited on T91 boiler tube steel substrate by high velocity oxy-fuel (HVOF) process to enhance high-temperature corrosion resistance. High-temperature performance of bare, as well as HVOF-coated steel specimens was evaluated for 1500 h under cyclic conditions in the platen superheater zone coal-fired boiler, where the temperature was around 900 °C. Experiments were carried out for 15 cycles each of 100 h duration followed by 1 h cooling at ambient temperature. The performance of the bare and coated specimens was assessed via metal thickness loss corresponding to the corrosion scale formation and the depth of internal corrosion attack. The uncoated boiler steel suffered from a catastrophic degradation in the form of internal oxidation attack and thickness loss. The 75Cr3C2-25NiCr coating showed good adherence to the boiler steel during the exposures with no tendency for internal oxidation.

19 citations


Journal ArticleDOI
TL;DR: In this article, a methodology for the integrated development of the product and of the business model for a hardware startup is presented, which is based on a micro cycle for the problem-solving procedure on the level of single process steps as well as on a macro cycle as procedure for the overall integrated development.
Abstract: Startups can substantially contribute to the industrial development in the early and newly industrialized countries by transforming technological inventions into products and services. By means of the market dynamics of cooperation and competition in global value creation and knowledge networks, new products and services can conduce to a global industrial development. Hence, in pursuance of an efficient and effective startup development, this paper will present a new methodology for the integrated development of the product and of the business model for a hardware startup. Hardware startups address the development of innovative tangible products. The hardware product itself may consist of mechanical, electronical, and software components. The methodology is based on a micro cycle for the problem-solving procedure on the level of single process steps as well as on a macro cycle as procedure for the overall integrated development of the startup. For each phase of the macro cycle, specific modelling methods for the product and business model are proposed. Finally, a proof of concept on the basis of a student startup, which is developing a micro wind turbine, will be presented.

17 citations


Journal ArticleDOI
TL;DR: In this paper, a dimensional accuracy of open cellular structures CoCrMo samples with designing volume based porosity ranging between 0 % (full dense) to 80 % was determined, and a maximum 2.10 % shrinkage was obtained by 80 % designed porosity sample.
Abstract: Designing orthodontic implants with desired physical and biological performances and to fabricate net shape with complex anatomical shapes is still a challenge. Cautious design approaches followed by systematic manufacturing techniques that can achieve balanced physical performance in mono block implants mechanics is necessary to accomplish this objective. Metal additive manufacturing (MAM) technique such as selective laser melting (SLM) process is progressively being utilized for new biomaterials such as cobalt-chrome-molybdenum (CoCrMo). This study was designed to determine a dimensional accuracy of open cellular structures CoCrMo samples with designing volume based porosity ranging between 0 % (full dense) to 80 %. A maximum 2.10 % shrinkage was obtained by 80 % designed porosity sample. Samples with higher volume-to-surface area (full dense) demonstrated the low total amount of shrinkage as compared to lower volume-to-surface area (80 % designed porosity).

17 citations


Journal ArticleDOI
TL;DR: In this article, the authors report on an ambitious project in the field of automation, applied to bound and free abrasive processing of precision and ultra-precision surfaces, with potentially far-reaching consequences.
Abstract: We report on an ambitious project in the field of automation, applied to bound and free abrasive processing of precision and ultra-precision surfaces, with potentially far-reaching consequences. This involves two main aspects:- directly processing surfaces using industrial robots, and combining robots with Zeeko CNC polishing machines to automate operations that are currently manual. These form steps towards our ultimate vision of the Integrated Manufacturing Cell for bespoke optics rather than mass-produced, and manufacture of other precision surfaces including prosthetic joint implants. Projects such as the European Extremely Large Telescope provide a relevant case study, where significant numbers of high-value bespoke optics are required.

15 citations


Journal ArticleDOI
TL;DR: In this article, a simple chemical hydrothermal treatment process was used to synthesize TiO2 nanotubes (TNTs) by applying 10 M NaOH and > 99.5% ethanol at 180°C for 24 hours.
Abstract: In this paper, TiO2 nanotubes (TNTs) were synthesized through simple chemical hydrothermal treatment process when anatase TiO2 nanopowder is chemically treated with 10 M NaOH and >99.5% ethanol at 180°C for 24 hr. According to the transmission electron microscopic (TEM) image analysis TNTs tubes were formed in the length sizes from 400 to 700 nm with inner diameter of 5 nm and outer diameter of 8 nm. The morphological and structural properties of synthesized TNTs was characterized by powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), UV–Vis diffuse reflectance spectra (DRS).

Journal ArticleDOI
TL;DR: In this article, a series of experiments were performed to study the growth mechanism of TiO2 thin films using TTIP and H2O by ALD, and the results showed that the effect of substrates on the growth of thin films was significant.
Abstract: Ceramic oxide thin films are an important material, with applications in many areas of science and technology. Titanium oxide (TiO2) is also a well-known and important material for applications such as gas sensors [1], photocatalysis materials [3], and electrochemicals [1], due to its self-cleaning [2], good corrosion resistance and biocompatibility. Atomic Layer Deposition (ALD) is a nanotechnology tool that is used for the deposition of nanostructured thin films. The unique advantage of ALD is the self-limiting film growth mechanism, which offers attractive properties, simple and accurate film thickness control, sharp interfaces, uniformity over large areas, excellent conformality, good reproducibility, a multilayer processing capability, and high quality films at low temperatures [3, 4]. TiO2 thin films were grown using TTIP (Titanium isopropoxide) ALD on silicon wafers, glass slides, and stainless steel plates in order to study the effect of substrates on the growth of TiO2. In order to achieve the desired advantages of using TTIP, a series of experiments were performed to study the growth mechanism of TiO2 thin films using TTIP and H2O by ALD.

Journal ArticleDOI
TL;DR: In this paper, uncured aerospace grade prepreg scraps resulted from the production waste were used to manufacture laminates, and they were tested in compression according to standard SACMA SRM 1R-94.
Abstract: The composite prepreg waste is still an environmental challenge. In the last decade, several researchers have been studying the recycling and reuse processes of composite components, mainly to use in secondary (non-structural) components. In this paper, uncured aerospace grade prepreg scraps resulted from the production waste were used to manufacture laminates. The carbon reinforcement of the prepreg presented plain weave style fabric. To manufacture the laminates the hand-lay up process was used, randomly positioning the scraps and without respecting the preferred directions of the warp and weft. Therefore, the resulting laminate is multidirectional (in the plane) and orthotropic. The cure was performed in autoclave at the maximum temperature of (180 ± 1)°C and pressure of 100 psi. This laminate was tested in compression according to standard SACMA SRM 1R-94. The results show an average compression resistance equivalent to that of laminates produced with continuous layers, although with a higher dispersion. In order to understand this variation, the fracture surfaces of the laminates were analyzed by scanning electron microscopy (SEM) in order to identify the failure modes. The specimens present shear and interlaminar failure modes, in addition to a mixed mode of failure (a transition between the shear and interlaminar failures). For the same specimen, the analysis of the internal arrangement of the fibers shows that changes in failure modes occur in regions where the carbon fabric is not continuous, i.e. there are joinings of scraps. It was also observed that none of the compression tests resulted in catastrophic failure of the specimens, possibly due to a greater resistance to fracture growth in the presence of mixed failure mode.

Journal ArticleDOI
TL;DR: In this article, the authors present some conjectures about how the metal absorbs the laser radiation and how rapid phase transformations take place, and propose that the interface response functions could be a possible way to understand phase transformations from liquid or high temperature solid solution conditions.
Abstract: Phase transformations in laser processed metallic materials usually occur under very high temperature gradients and during a short time. Therefore, laser materials processing has been usually associated to high heating and cooling rates. However, before understanding the temperature evolution of the target, the absorptivity and the optical penetration must be considered. This paper presents some conjectures about the how the metal absorbs the laser radiation and how rapid phase transformations take place. It would be proposed that the interface response functions could be a possible way to understand phase transformations from liquid or high temperature solid solution conditions. Finally, it will be presented some results about laser processed materials of aerospace interest: steels, titanium and aluminium, which will illustrate the practical applications of the theories.

Journal ArticleDOI
TL;DR: In this article, an experimental investigation of the resistance welding of PPS/carbon fiber is presented, where the more appropriate conditions for welding were evaluated based on a criterion of maximum lap shear strength, according to ASTM D1002-10.
Abstract: An experimental investigation of the resistance welding of PPS/carbon fiber is presented in this manuscript. Currently, one of the main problems of the structural polymer composites consists in its effective integration of the components. The electrical resistance welding has been considered as one of the promising techniques for bonding composites, because it is a quick process with easy surface preparation. To improve the process to welding poly-(phenylene sulfide) (PPS) reinforced with carbon fiber laminates, it was used a full factorial design (23). Considering the factors pressure, electrical current and time, the more appropriate conditions for welding were evaluated based on a criterion of maximum lap shear strength, according to ASTM D1002-10. A comparison between welded and non-welded specimens in terms of analysis dynamic mechanical (DMA), thermomechanical analysis (TMA) and vibration tests was performed. It was demonstrated that large-scale DMA presented a similar results but according to TMA and vibration test were observed that welded specimens presented different results when compared to non-welded laminates, due probably to the presence of metallic heating element.

Journal ArticleDOI
Yan Bao1, Zhigang Dong1, Renke Kang1, Zhao Li1, Yi Chu Yuan 
TL;DR: Based on the instantaneous rigidity force hypothesis, a milling force model for mirror milling of aircraft skin was proposed in this article, which was validated by the milling forces measurement during mirror millings experiments.
Abstract: Machining the aircraft skin, using CNC milling to replace the traditional chemical milling, is a trend owning to the great pollution of the chemical milling to the environment. Based on the instantaneous rigidity force hypothesis, a milling force model for mirror milling of aircraft skin was proposed, which was validated by the milling force measurement during mirror milling experiments. A FEM model was established to calculate the deformation of the aluminum plate in mirror milling. The effects of the supporting position on the deformation was analyzed.

Journal ArticleDOI
TL;DR: In this article, the authors deal with a natural frequency distribution of a six-axis industrial robot in order to analyze chatter vibrations in upcoming milling processes and derive a mathematical model that predicts the natural frequencies of the robotic structure for any joint configuration within the considered workspace.
Abstract: This paper deals with a natural frequency distribution of a six-axis industrial robot in order to analyze chatter vibrations in upcoming milling processes. Since the dynamic vibration behavior of the robotic system can be manipulated by changing the robot’s joint configuration, experimental modal analysis is performed to determine the natural frequencies in the entire workspace. In this study, methods of design of experiments are used to derivate a mathematical model that predicts the natural frequencies of the robotic structure for any joint configuration within the considered workspace.

Journal ArticleDOI
TL;DR: In this article, the influence of fiber orientation on the machined surface quality of unidirectional T800/X850 CFRP laminates during milling was discussed and four group milling tests were conducted under the fiber orientation angle of 0°, 45°, 90° and 135°, respectively.
Abstract: Machined surface quality is the deciding factor when evaluating the machinability of CFRP. This present work concerns the influence of fiber orientation on the machined surface quality of the machined surface in terms of surface morphology and surface roughness during milling of unidirectional T800/X850 CFRP laminates. Four group milling tests are conducted under the fiber orientation angle of 0°, 45°, 90° and 135°, respectively. For the fiber orientation angle of 0°, the machined defects are mainly fiber pull-out and fiber brittle fracture owing to interfacial debonding between the fibers and matrix resin. For the fiber orientation angle of 45°, the machined defects are mainly resin cavities and the surface morphology is rough and presents wavy fractures. For the fiber orientation angle of 90°, smooth or neat surface is observed except for the surface as the cutting tool cutting in the workpiece on which severe cracks are observed. For the fiber orientation angle of 135°, the surface is smooth with less fibers pull-out. Evaluation profile and surface roughness of the machined surfaces were measured as well. Dramatically fluctuate of the evaluation profile is observed for the fiber orientation angle of 45° with a high surface roughness Ra. Verification tests were also conducted on the multidirectional CFRP (cross-ply) laminates. It is indicated that the presence of the fiber orientation angle of 45° is the main factor leading to the decline of the machined surface quality.

Journal ArticleDOI
TL;DR: In this article, chemical composition analysis, particle size analysis, amorphous and crystalline phases present, bonding nature, and microstructural behavior are used to determine the suitability of fly ash for geopolymer synthesis.
Abstract: Fly ash is a pozzolanic material which is produced during coal combustion in thermal power plants. This paper investigates the suitability of Malaysian fly ash for geopolymer synthesis. Chemical composition analysis, particle size analysis, amorphous and crystalline phases present, bonding nature, and microstructural behavior are used to determine the suitability of fly ash for geopolymer synthesis. The results showed that fly ash contains silica, alumina, ferrous oxide, and calcium oxide in major proportions which are the main ingredients required for geopolymer synthesis. Higher portion of particles having size in the range of 1-15 µm. Fly ash contains quartz, mullite, and ferrite as the crystalline compounds while the major portion of fly ash is in amorphous form. The band due to asymmetric stretching vibration mode of Si-O-T appears at 1095 cm-1 which is the main band used to follow geopolymer formation. Microstructure of fly ash shows that the higher portion of fly ash is in amorphous form while it contains cenospheres, magnetic spheres, carbon, and a large number of small particles. Malaysian fly ash is a suitable material for geopolymer and it can be used for geopolymer synthesis.

Journal ArticleDOI
TL;DR: An experimental investigation of hole machining performance for woven carbon-fiber reinforced PEEK (polyetheretherketone) sheets by an abrasive waterjet (AWJ) is presented in this article.
Abstract: An experimental investigation of the hole machining performance for woven carbon-fiber reinforced PEEK (polyetheretherketone) sheets by an abrasive waterjet (AWJ) is presented. It is shown that AWJ machining can produce good quality holes if the cutting parameters are properly selected. Plausible trends of the hole quality with respect to the process parameters are discussed. Nozzle traverse speed and intended or programmed hole size are found to have a significant effect on the diameter error of the machined holes, hole roundness, and hole wall inclination angle, while water pressure and abrasive mass flow rate exhibit an insignificant effect. An increase in the traverse speed decreases the overall hole quality, while an increase in the programmed hole diameter decreases the hole diameter error and roundness error, but increases the hole wall inclination. There is not any clear trend of the hole wall surface roughness with respect to the process parameters. Moreover, high water pressures may result in hole defects, such as entrance surface chipping, delamination, internal cracking and fiber pull-out. It is found that the optimum process parameters are about 200 MPa water pressure, 2 mm/s nozzle traverse speed and 7.0 g/s abrasive mass flow rate. Recommendations are made for compensating for the hole size deviation and empirical models are fianlly developed for these hole characteristics.

Journal ArticleDOI
TL;DR: In this paper, nanoindentation was performed on a 4H-SiC wafer and the change of hardness with the angle between the wafer orientation flat and the indenter edge, the maximum load and the loading rate were investigated.
Abstract: In order to clarify the mechanical properties of single-crystal silicon carbide (SiC), nanoindentation was performed on a 4H-SiC wafer. The change of hardness with the angle between the wafer orientation flat and the indenter edge, the maximum load and the loading rate were investigated. The hardness reached maximum at an indentation load of 12 mN in the range of 3-50 mN. Hardness decreased under two conditions: when the edge of the indenter tip is parallel to the [11-20] direction, and when a very low loading rate was used. Transmission electron microscopy was used to observe dislocations and cracks under the indents. It was demonstrated that the deformation process of SiC involved three steps with respect to the increase of the indentation load. These results provide information for improving ductile machining process of single crystal SiC.

Journal ArticleDOI
TL;DR: In this paper, the authors present a methodology which shows how to evaluate and select highly iterative product development methods for individual development scopes in a startup enterprise and evaluate the suitability of these methods for the respective project.
Abstract: Today’s manufacturing companies are exposed to the challenge of fulfilling constantly growing and heterogeneous customer expectations. Simultaneously, the demand for delivering the highest quality in shortest time increases strongly. One way to handle these requirements is the highly iterative product development approach. By distributing development processes in short and iterative sub-processes, this method generates customer oriented and marketable products. However, most producing companies fail by trying to adopt the short-cycled concept without considering the suitability of these methods for the respective project. According to that fact, this paper aims at the presentation of a methodology which shows how to evaluate and select highly iterative product development methods for individual development scopes. A first application of this methodology indicated affirmative results regarding to the practicability within a startup enterprise. Still, there is need for further research, especially in the field of implementation.

Journal ArticleDOI
TL;DR: In this paper, the choice of the right tool materials for machining titanium alloys contributes enormously to reducing the overall machining time by significantly lowering the cycle time and indexing of the cutting edges.
Abstract: Machining efficiency of titanium alloys is crucial to the aerospace industry especially in the manufacture of bladed discs (blisks) where over 80% of titanium alloy material is roughed out to generate the complex shapes and contours of components. The choice of the right tool materials for machining titanium alloys contributes enormously to reducing the overall machining time by significantly lowering the cycle time and indexing of the cutting edges. These improvements lead to a reduction of the manufacturing cost by up to 30%. Uncoated and coated carbide tools have demonstrated encouraging performances when turning Ti-6Al-4V alloy, especially under roughing operations complemented by high pressure cooling technology, at high cutting speed and depth of cut conditions that increase the metal removal rate. Under such cutting conditions there is no significant difference in performance between coated or uncoated carbide tools when turning Ti-6Al-4V alloy. Super abrasives like ceramics and cubic boron nitride (CBN) tools are not suitable for machining titanium alloys as low tool life with no economic benefit is achieved because of severe chipping and fracture of the cutting edge. Machined surfaces produced with ceramic tools have very low surface integrity status because of loss of form as a result of accelerated tool wear and the consequent chipping and fracture encountered during machining. Polycrystalline diamond (PCD) tools are suitable for finish turning Ti-6Al-4V alloy at cutting speeds up to 250 m/min.

Journal ArticleDOI
TL;DR: In this article, the authors describe tooling concepts and design methods for the manufacturing of intrinsic hybrid parts for rotational and planar parts with thermosetting or thermoplastic matrix material.
Abstract: The increasing use of hybrid materials requires efficient manufacturing processes. With the concept of the intrinsic hybrids the shaping or forming of the part is combined with the hybridization in the same process step and thereby the same tool. Hence new tooling concepts, which realise the process requirements, are necessary. This paper describes tooling concepts and design methods for the manufacturing of intrinsic hybrid parts. Different solutions for rotational and planar parts with thermosetting or thermoplastic matrix material are presented. Additionally the integration of inserts in such tools is discussed. Finally the main challenges for the design of tools for intrinsic hybrids will be presented.

Journal ArticleDOI
TL;DR: In this paper, finite element analysis and mechanical characterization of porous medical grade cobalt chromium (CoCr) alloy in cubical structures with volume based porosity ranging between 60% and 80% produced using SLM rapid manufacturing process.
Abstract: The recent introduction of selective laser melting (SLM) for the processing of medical grade cobalt chromium (CoCr) alloy has led to a complex shape fabrication of porous custom CoCr alloy implants with controlled porosity to meet the requirements of the anatomy and functions at the region of implantation. This paper discusses finite element (FE) analysis and mechanical characterization of porous medical grade CoCr alloy in cubical structures with volume based porosity ranging between 60% and 80% produced using SLM rapid manufacturing process. Analysis by FE is considered beneficial to predict the effective mechanical properties of the porous structures manufactured by SLM due to minimization of the need for expensive and time consuming physical testing. Cellular structures modelling for fabrication with Direct Metal Laser Sintering machine were designed to vary between 60% and 80% to study the effect of structural variation on mechanical properties of the cellular porous structure. ANSYS 14.0 FE modelling software was used to predict the effective elastic modulus of the samples and comparisons were made with the experimental data. FE results show that with the material properties in the functions of porosities, minimum mesh size of 0.2 mm for triangular shape mesh and boundary as well as load conditions as applied in this study, agreement in equivalent stress, strain and deformation with the experimental results can be achieved to some extent. The technique for FE in this study can be used to investigate stress distribution in three dimensional model of real bone.

Journal ArticleDOI
TL;DR: Co3O4/SiO2 nanocomposite was obtained via citrate-gel method in this paper, where 22 nm in size Co 3O4 particles in an amorphous SiO2 matrix were obtained.
Abstract: Co3O4/SiO2 nanocomposite was obtained via citrate-gel method. 22 nm in size Co3O4 particles in an amorphous SiO2 matrix were obtained. Co3O4:SiO2 wt. ratio was verified using EDX and found to be close to the 80 % nominal ratio. The UV-Vis measurements showed broad absorption bands at around 440 and 790 nm. The optical band gap values were 1.95 and 1.35 eV respectively, being close to those observed for pure Co3O4 nanoparticles. The electrochemical measurements in 5 M KOH solution were performed using a three-electrode type system. Co3O4/SiO2 nanocomposite exhibited high specific capacitance reaching 758 F g-1 at 2.5 mV s-1. Very small solution and electrode-electrolyte interfacial charge transfer resistances were obtained when impedance spectra were analysed.

Journal ArticleDOI
TL;DR: A comparative study of non-imaging and imaging based particle size analysis tools to analyze the limitations and advantages of using such equipment is conducted in this article, where the authors used particle size analyzer (PSA) and light microscope as imaging tool to determine particle sizes in various waste water samples.
Abstract: Wastewater originated from domestic or industry use need to be treated before discharge it to the environment. Particle size is one of the parameter that determine efficient operation of wastewater treatment plant. The present work conducts a comparative study of non-imaging and imaging based particle size analysis tools to analyze the limitations and advantages of using such equipment. The study utilizes particle size analyzer (PSA) as non-imaging tool and light microscope as imaging tool to determine particle sizes in various waste water samples. For this analysis domestic wastewater influent and effluent are analyzed with both techniques. In addition, palm oil mill effluent (POME) has also been analyzed after Fenton process to compare the particle size using these tools. PSA shows most of the particles in the influent and effluent are in the size range of 100 to 700 μm, while microscopy shows additional information of aggregates structure in POME sample showing promising possibility of identifying complex structure of aggregates present in the sample.

Journal ArticleDOI
TL;DR: In this article, the authors synthesize the ionic liquid polymer incorporating activated carbon and investigate its performance for CO2 capture and separation, and the results revealed that activated carbon has been successfully incorporated into the lattice structure of polymer materials.
Abstract: CO2 capture and separation by ionic liquid is one of the fastest growing branches in ionic liquid technology. The aim of this research was to synthesize the ionic liquid polymer incorporating activated carbon and investigating its performance for CO2 capture and separation. The ionic liquid monomers 1-vinyl-3-ethylimidazolium bromide, [veim][Br] and 1-vinyl-3-ethylimidazolium bis (trifluoromethyl-sulfonyl) imide, [veim][Tf2N] were first synthesized and then polymerized into ionic liquid polymers incorporating activated carbon. The purity of the [veim][Br] and [veim][Tf2N] was verified by 1H NMR, 13C NMR and Ion Chromatography. Both monomers were proved to be in high purity. The elemental composition of both polymer materials synthesized were examined using energy dispersive X-ray spectroscopy (EDX) and the morphology of the synthesized material was observed using field emission scanning electron microscopy (FESEM). The results revealed that activated carbon has been successfully incorporated into the lattice structure of polymer materials. The fabricated polymer materials would be expected to have higher CO2 capture capability as it combines both the absorption and adsorption mechanism for CO2 apprehension and sequestration.

Journal ArticleDOI
TL;DR: In this paper, the simulative engineering of metal-composite interfaces is discussed and several design aspects on the microscale and macroscale are explained and methods to model the mechanical behaviour of the interface within finite element simulations are discussed.
Abstract: This contribution gives an overview of the simulative engineering of metal-composite interfaces. To this end, several design aspects on the microscale and macroscale are explained and methods to model the mechanical behaviour of the interface within finite element simulations are discussed. This comprises the utilization of cohesive elements with a continuum description of the interface. Likewise, traction-separation based cohesive elements, i.e. a zero-thickness idealization of the interface, are explained and applied to a demonstration example. Within these finite element simulations, the constitutive behaviour of the connected components has to be described by suitable material models. Therefore, inelastic material models are formulated based on rheological models.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the potential of MIL(Materials Institute Lavoisier)-101 as CO2 capture and storage candidate by conducting an experiment with different pressure between the synthesised and modified MIL-101 using Multi-wall carbon nano tubes (MWCNTs).
Abstract: Nearly 40% of the world gas reservoir contains high level of CO2 that stance problems to development. The discovery of natural gas field with CO2 content of as high as 87% in Malaysia poses new challenges in terms of the CO2 separation processes. This research work investigates the potential of MIL(Materials Institute Lavoisier)-101 as CO2 capture and storage candidate by conducting an experiment with different pressure between the synthesised and modified MIL-101 using Multi-wall carbon nano tubes (MWCNTs). To investigate the effect of the MWCNTs in MIL-101 towards CO2 adsorption performance. The synthesized MOFs were characterized using scanning electron microscopy (SEM) for surface morphology, Thermogravimetric analysis (TGA) for thermal stability, X-ray diffraction (XRD) for crystals plane, Brunauer-Emmet-Teller (BET) for surface area and CO2 adsorption performance. The result had showed that the modified MIL-101 enhanced the CO2 adsorption compared to the pure MIL-101. MWCNT@MIL-101 showed the adsorption of CO2 uptake is 0.0029mmole-1/g at 100kPa.