O.M.F. Marwah

Segmented Capacitance Tomography Electrodes: A Design and Experimental Verifications

A segmented capacitance tomography system for real-time imaging of multiphase flows is developed and presented in this work. The earlier research shows that the electrical tomography (ECT) system is applicable in flow visualization (image reconstruction). The acquired concentration profile obtained from capacitance measurements able to imaged liquid and gas mixture in pipelines meanwhile the system development is designed to attach on a vessel. The electrode plates which act as the sensor previously has been assembled and fixed on the pipeline, thus it causes obscurity for the production to have any new process installation in the future. Therefore, a segmented electrode sensor offers a new design and idea on ECT system which is portable to be assembled in different diameter sizes of pipeline, and it is flexible to apply in any number due to different size of pipeline without the need of redesigning the sensing module. The new approach of this sensing module contains the integration intelligent electrode sensing circuit on every each of electrode sensors. A microcontroller unit and data acquisition (DAQ) system has been integrated on the electrode sensing circuit and USB technology was applied into the data acquisition system making the sensor able to work independently. Other than that the driven guard that usually placed between adjacent measuring electrodes and earth screen has been embedded on the segmented electrode sensor plates. This eliminates the cable noise and the electrode, so the signal conditioning board can be expanded according to pipe diameter.

Direct Fabrication of IC Sacrificial Patterns via Rapid Prototyping Approaches

Patterns made from conventional wax materials in the Investment Casting (IC) process can easily be distorted, damaged, or broken in transportation or routine handling or due to exposure to heat. Alternatively, the strength and toughness of most Rapid Prototyping (RP) materials virtually eliminates this drawback due to their resistance to heat, humidity, and post curing. The current study is conducted to investigate the feasibility of using RP processes such as FDM and MJM to fabricate IC patterns from Acrylonitrile Butadine Styrene (ABS) and acrylate based materials respectively to be used directly in IC process. Evaluation of the effects of different internal pattern designs of the RP parts are conducted based on the thermal analysis approach and burnout properties of the RP patterns. Ceramic shell molds are fabricated on both RP patterns and subsequently placed in an oven which is gradually heated to 1000 °C. The decomposition temperature and the residual ash of the RP pattern materials is determined and analyzed. Results show that the acrylate pattern ofMJMdecomposes rapidly compared to the ABS pattern from the FDM process. It is also observed that quasi and square hollow internal structures show better collapsibility or burnout properties, with no cracks, compared to cross pattern and cross hatch designs.

Advances in High Temperature Materials for Additive Manufacturing

In todays technology, additive manufacturing has evolved over the year that commonly known as 3D printing. Currently, additive manufacturing have been applied for many industries such as for automotive, aerospace, medical and other commercial product. The technologies are supported by materials for the manufacturing process to produce high quality product. Plus, additive manufacturing technologies has been growth from the lowest to moderate and high technology to fulfil manufacturing industries obligation. Initially from simple 3D printing such as fused deposition modelling (FDM), poly-jet, inkjet printing, to selective laser sintering (SLS), and electron beam melting (EBM). However, the high technology of additive manufacturing nowadays really needs high investment to carry out the process for fine products. There are three foremost type of material which is polymer, metal and ceramic used for additive manufacturing application, and mostly they were in the form of wire feedstock or powder. In circumstance, it is crucial to recognize the characteristics of each type of materials used in order to understand the behaviours of the materials on high temperature application via additive manufacturing. Therefore, this review aims to provide excessive inquiry and gather the necessary information for further research on additive material materials for high temperature application. This paper also proposed a new material based on powder glass, which comes from recycled tempered glass from automotive industry, having a huge potential to be applied for high temperature application. The technique proposed for additive manufacturing will minimize some cost of modelling with same quality of products compare to the others advanced technology used for high temperature application.

The effect of alkali treatment under various conditions on physical properties of kenaf fiber

Alkali treatment was known as one commonly used treatment for natural fiber and obtained a good fiber matrix adhesion, thermal and mechanical properties of composite. This paper reports the effect of alkali treatment conditions on the physical properties of kenaf fiber such as density, weight loss, diameter, cross sectional and fiber morphology. In this study, kenaf fiber were treated under various conditions alkali concentration at 2, 6 and 10 (w/v%), immersion duration at 30, 240 and 480 minute and immersion temperature at 27, 60 and 100°C. The effects of alkali treatment on kenaf fiber physical properties under various conditions were explored. Alkali treatment conditions setting have an impact on kenaf bast fiber physical characteristics. In kenaf fiber density, it was found that a small increase of kenaf density value after alkali treatment compared to untreated kenaf fiber. When each of alkali treatment parameters increased, kenaf fiber density also increased slightly. Kenaf fiber weight loss also exhibit a similar pattern of small increment with the increase of treatment parameters. Additionally, kenaf fiber diameter and cross sectional area show a decline pattern after treated with alkali. Furthermore, this decline pattern was corresponding with the increasing level of alkali treatment parameters. The maximum of kenaf diameter reduction was recorded at high level of each alkali treatment parameters.

Direct rapid prototyping evaluation on multijet and fused deposition modeling patterns for investment casting

The continuation from rapid prototyping into rapid tooling technologies allows speedy fabrication of sacrificial patterns for investment casting process. Direct expendable pattern fabrication with intricate features using rapid prototyping techniques significantly reduces the fabrication cost when associated with single- or low-volume production. During investment casting process, rapid prototyping patterns are subjected to high melting temperatures, high viscosities, and high thermal stress such as dewaxing and shell mold cracking. Furthermore, ceramic shell may cause crack during melting and burning out of the patterns and also incomplete collapsibility. Although rapid prototyping process can build parts with high stiffness rapidly, the part surface suffered a staircase effect and shrinkage during investment casting process solidification. This paper presents a direct approach of multijet modeling and fused deposition modeling on acrylate- and acrylonitrile–butadiene–styrene-based materials to be used as expendable patterns for the investment casting process. Thermal analyses were conducted on the rapid prototyping materials that exhibit mass loss and expansion. Quality assessment and benchmarking were performed between the rapid prototyping and the metal part on accuracy, surface roughness, and part built time. It was found that both the materials have dimensional deviation when employed in investment casting process and acrylate patterns have better surface roughness as compared to acrylonitrile–butadiene–styrene patterns. Additionally, multijet modeling recorded a significantly shorter lead time when more than a single part can be produced during the rapid prototyping process. It was observed that the shell mold after burnout experiences cracking. Results also showed that acrylate-based materials decomposed above 500℃, meanwhile acrylonitrile–butadiene–styrene was above 600℃. Acrylate material had a coefficient of thermal expansion and linear dimensional deviation as compared with acrylonitrile–butadiene–styrene. No ash was observed in the ceramic molds when the part burnout temperatures are above 500℃ acrylate material and 600℃ for acrylonitrile–butadiene–styrene.

Direct investment casting numerical study for ABS P400 FDM materials

The purpose of this paper is to present the study of internal structure for investment casting Fused Deposition Modeling (FDM) , and compare it between open and closed ceramic cube . This research aims to introduce a new internal structure for investment casting FDM pattern. With modeling 3D-thermal condition with mechanical finite element analysis on cube ceramic shell open and closed type (during burnout stage) have been computed. As numerical observation the deformation stress for cube square 90° and hollow models with two variants cube open and closed have been evaluated by put the temperature at model. Model was be imposed until 700 °C. Several investigations indicate the probability of better performance for influencing factor drainage ability for each model. However the main scope of the paper is to compare the performance of model during burnout stage ( the deformation on ceramic shell ) . Therefore, a more analytical and practical approach will be good for future research for other mentioned factors. A new generation of internal structure (or a new build style) for investment casting FDM patterns is presented here. The significant reduction of critical loadings on ceramic shell will ensure investment casting foundries for using FDM patterns, which are by square 90° and hollow models.

3D Printer Patterns Evaluation for Direct Investment Casting

The term direct investment casting represents the employment of pattern fabricated by rapid prototyping technique have been reduce the cost and production lead time. The non-wax materials having robust ability on producing pattern in accuracy stability and clean burnout. However 3D printer (3DP) parts are powder based materials and not easily burnout during firing process. The purpose of this investigation were to evaluate the ZP150 powder materials as a sacrificial pattern to be used in investment casting (IC) process. Result shows powder based patterns of 3DP process failed to disintegrate completely even at high temperature during collapsibility investigations. However the pattern become brittle and easily remove by water pressure. Therefore the ceramic mould can be used for metal casting.

Feasibility study of Thermal Electric Generator Configurations as Renewable Energy Sources

Thermoelectric Generator is a solid state device that able to convert thermal energy into electrical energy via temperature differences. The technology is based on Seebeck effect that was discovered in year 1821, however till now there is no real application to exploit this capability in mass scale. This research will report the performance analysis of TEG module in controlled environment of lab scale model. National Instrument equipment and Labview software has been choosen and developed to measure the TEG module in various configurations. Based on the experiment result, an additional passive cooling effort has produced a better ΔT by 7°C. The optimal electrical loading of single TEG is recorded at 200Ω. As for circuit connections, series connection has shown superior power output when compared to parallel connection or single TEG. A series connection of two TEGs has produced power output of 416.82μW when compared to other type connections that only produced around 100μW.

PCL/PLA Polymer Composite Filament Fabrication using Full Factorial Design (DOE) for Fused Deposition Modelling

In this study, Polycaprolactone / Polylactice Acid (PCL/PLA) composite are used to fabricate filament wire with the specific diameter, which is in the range of 1.75 to 1.80 mm. Full factorial experimental design technique was used to study the main effects and the interaction effects between operational parameter which is (A) die temperature, (B) roller puller speed, (C) spindle speed and (D) inlet temperature. Besides that, there are two levels (-1 and +1) and the response are filament wire diameter. There are 16 numbers of runs and plus 8 centre points per blocks which makes the runs into 24 runs. From the experiment it shows that there are four factor that are significant effects on the filament wire diameter which is A, B, C and BC. The optimum parameter setting are also determined and there are 10 suggestions to achieve the target with different setting of parameter. The margin error for confirmation run is below than 15% when the parameter set at 6 Hz spindle speed, 4.99 rpm roller puller, 100.31 °C die temperature and 79.65 °C inlet temperature which can be noted that the confirmation run result is acceptable. The optimization parameter setting can use to continue in Fused Deposition Modelling (FDM). Filament wire from PCL/PLA are succesfully fabricated with acceptable diameter size and ready to be used for Fused Depotion Modelling process (FDM).

Development of Mould of Rheology Test Sample via CadMould 3D-F Simulation

This research was about the development of mould for rheology test sample via simulation. The development work concerned with stages of design, simulation, analysis, and fabrication of the mould to produce good quality samples. In the design stage, three mould concepts have been prepared via Solid Works software. The simulation of injection moulding was conducted by using CadMould 3D-F software. Then, in the analysis stage, the main factor that has been studied were the cavity system, runner system and the gating system. For each design, different type of systems were applied to compare different simulation result. Through the simulation software, it was rectified that the parameter such as the number of cavities, filling time, shear stress were the main factors to contribute good rheological properties of the sample. The final result shows that Design 2 was chosen as the suitable mould due to number of cavities and good results in the analysis, as compare to other mould design. Finally, Design 2 have been fabricated and undergo fitting test to see whether the dimension had been done correctly. Based on this research findings, it was proven that to develop a mould suitable for rheology sample, the mould design selection should be made based on the type of system in simulations.