Control of spatial deposition of electrospun fiber using electric field manipulation

A significant challenge in the synthesis of uniform membranes via electrospinning is achieving a spatially uniform deposition of electrospun fibers. The problem is more pronounced in the case of a multi-spinneret system due to self repulsion between the jets. In this study, electric field manipulation (via auxiliary electrodes) is explored as a potential technique for controlling the spatial deposition area of electrospun fiber. It was observed experimentally that the location and size of the deposition area can be moved linearly in response to the applied voltages at the auxiliary electrodes. Finite element analysis (FEA) was used to simulate the electric field strength and distribution at a given applied voltage and its effect on the flight path of electrospun fiber. Comparisons between experiments and simulations were made in evaluating the accuracy of simulations. The adaptation of this technique in production would provide a method of controlled deposition for producing uniform electrospun fiber membranes

Manipulation of electrospun fibres in flight: the principle of superposition of electric fields as a control method

This study investigates the magnitude of movement of the area of deposition of electrospun fibres in response to an applied auxiliary electric field. The auxiliary field is generated by two pairs of rod electrodes positioned adjacent and parallel to the line of flight of the spun fibre. The changes in shape of the deposition area and the degree of movement of the deposition area are quantified by optical scanning and image analysis. A linear response was observed between the magnitude of movement of the deposition area and voltage difference between the auxiliary and deposition electrodes. A squeezing effect which changed the aspect ratio of the deposition area was also observed to result from the application of symmetric electrical fields. Statistical analysis showed that the deflection and squeezing responses can be thought of as independent control actions. The results from this experiment suggest this particular application of superposition of electric fields could be used as to control the flight path of an electrospun fibre

Investigation of pressure drop in hydro-pneumatic driveline propulsion system for dual hybrid passenger vehicle

The study focused on investigating the pressure drop/loss of the hydro-pneumatic driveline propulsion system. Previous research has shown that there is a very high power loss in the hydro-pneumatic propulsion system. Therefore, this research is carried out to identify the behaviour, cause and strategy to overcome this problem. The Hydraulic Hybrid Vehicle (HHV) is a new technology under development to improve fuel eficiency in passenger vehicles. However, this system is still under research and development phase. There is still a great deal of uncertainty about the performance of this system. In this research, the functional schematic diagram of the charging and propulsion was designed and simulated by using Automation Studio software. The real-time data and pressure behaviour of hydro- pneumatic driveline propulsion obtained by running the system without load condition. As a result, the highest value of losses occurred at (psys - p1), stage 1, from the supply to the input of the valve. The value is around 68 to 69 bar and occurred at psys = 220 bar. (p2 - p3) showed the lowest losses overall. The lowest pressure loss value occurred at psys = 100 bar, which is around 17 to 18 bar. The pressure drop happened to be high due to the improper selection of hose diameter represented by (psys - p1). The loss of (p1 – p2) was due to diameter and angle of connector too sharp that caused disturbance to the flow and p3 is developing back pressure at return line. The stage pressure monitoring was used to narrow down the root cause, and some papers have been used to validate the behaviour

An Experimental Study of the Influence of Fiber Architecture on the Strength of Polymer Composite Material

The study focuses on the influence of fiber architecture (sequence and orientation) on flexural strength of glass fiber reinforced composite material. Composite materials are used increasingly in various fields such as space and aviation industries, architectural structures, shipbuilding materials, sporting goods, and interior and structural materials of automobiles due to the excellence of mechanical characteristics as well as light weight, heat resistance, and control characteristics. The main purpose of this study is to obtain the effects of fiber sequence and orientation to the flexural properties of laminated polymer composite material. Glass fiber reinforced polymer laminates are produced with each laminate consists of four layers of lamina. The matrix used is thermoset polyester with woven roving and chopped strand mat E-glass fiber as reinforcement materials. Each sample is different from another in terms of stacking sequence and orientation angles. Hand lay-up process is used to produce composite laminates and a tungsten carbide jigsaw cutter is used to cut the samples to required dimensions. The experimental work is carried out in accordance to three-point flexure test of ASTM-D790. It is noted from this work that the existence of chopped strand mat had significantly improved the flexural properties of the composite laminates

F-Chart Method For Design Domestic Hot Water Heating System In Ayer Keroh Melaka

Renewable energy is an alternative approach of energy supply that meets the needs of the present generations without compromising the ability of future generations to meet their own needs. One type of renewable energy is solar energy. Solar energy systems convert solar energy into useful energy. In designing a solar collector, there are predictable and unpredictable parameters that are considered. Predictable parameters include performance characteristics of collector and mainly concern weather data such as solar radiation, ambient temperature, wind speed, direction, and other parameters is performance characteristics of collectors. This work analysed the use of the f-chart method in design liquid solar heating systems due to its simplicity and ability to estimate the fraction of total heating load supplied by the solar heating system. This method is very commonly used in designing for both active and passive solar heating systems, especially in selecting sizes and type of solar collectors that provide the hot water and heating loads. In this research, the data of the project is analysed to calculate based on the f-chart graph. The results show that the area in Melaka around the vicinity of Ayer Keroh is suitable for the installation of the flat-plate solar collector. The total annual heating load of domestic hot water in Melaka is 9.55 GJ and the annual fraction of the load supplied by solar energy is 78.42% which is suitable for implementation and installation in Ayer Keroh, Melak

A Comparative Study Between Weighing and Image Analysis Techniques for Predicting the Amount of Deposited Electrospun Nanofibres

Weighing and direct measurement are currently the two most common techniques used for estimating the amount of deposited nanofibres in electrospinning process. Nevertheless, due to its extremely small fibre size and mass, the task of measuring the weight or thickness of an electrospun nanofibres membrane is difficult and the results are arguable. This study evaluates the effectiveness of using greyscale image analysis for predicting the amount of deposited nanofibres compared to weighing technique. Polyvinyl alcohol electrospun nanofibres were collected at different deposition times on A4 black paper substrates. The substrates were weighed before and after deposition process and then scanned into 8 bit greyscale images. Analyses were carried out using ImageJ software, statistical analysis, high speed camera and scanning electron microscopy. At long deposition times, both techniques showed significant correlations between the measured values and deposition times. However, at short deposition times the weighing technique was found unreliable (p>0.05) compared to image analysis technique due to insignificant fibre masses compared to the weight variation of the substrates. Results suggest that image analysis technique was a better option to be used compared to weighing technique. This technique has the potential to be used as an automated online quality control in electrospun nanofibres manufacture

EFFECT OF LOAD AND TEMPERATURE ON FRICTION USING BANANA PEEL BLENDED WITH PARAFFIN OIL UNDER HIGH LOADING CAPACITY

 Increased severity in operating conditions coupled with the environmental and toxicity issues related with using conventional lubricants. In addition, high price of fossil fuels has led to exploration of new kind natural additives as bio-lubricant. Banana Peel as agricultural wastes are potential to be developed as bio-oils that to replace the petroleum products, due to their environmentally friendly characteristics, biodegradable, nontoxic and renewable. The purpose of this study is to produce lubricant oil from Banana Peel (BP) as bio additives in paraffin oil, as well as to determine their physical and tribological properties as bio-lubricant under severe operation conditions to identify their ability for lubricants. Tribological performance of Banana Peel (BP) as a bio-lubricant was tested using four-ball test machined under extreme pressure conditions, according to ASTM D 2783-03. Experimental results showed significant improvement in overall performance with increased BP content compared with paraffin oil (PO) through Coefficient of Friction parameter (COF) at 100 ˚C, lower value of COF which 0.086 for 50 %BP followed by 20% BP, 5% BP and 100 %PO at values 0.089, 0.456 and 0.595 respectively. As results, banana peel as Extreme Pressure and Anti-Wear additives has been proven itself able for use in lubrication applications for gear and engine oils

An investigation of using grey scale image analysis for predicting the amount of deposited electrospun nanofibres

When electrospinning, the amount of electrospun fibres deposited is difficult to determine due to the extremely small size and light weight of the fibres. Several methods have been used to predict the amount of deposited fibres including weighing, imaging and direct measurement. Although these methods work to a certain extent, they all have drawbacks that make them unsuitable for commercial scale process control. The methods are generally time consuming, destructive and only examine a small area of web. In this study, an image analysis method is used to predict the amount of electrospun fibres deposited over a significant area. When images of electrospun fibres are converted into grey scale images, it is suggested that the amount of fibres deposited can be predicted by measuring the grey scale intensity. A conventional weighing method was used to validate the image analysis results. The weighing method was found wanting when the deposition time was short (p>0.05). This was because the measured fibre masses were insignificant compared to the weight variation of the collector substrates. Statistical analyses showed that there were a strong correlation between grey scale intensity and deposition time especially at short deposition times. The results suggest that image analysis method could be used to predict the amount of deposited electrospun nanofibres. Further test on different polymers and different coloured substrates showed that the method was still capable to distinguish the samples. The developed method has the potential to be applied as an in-line non-destructive quality control method for electrospun fibre manufacture

Preparation, Characterization, and Electrical Conductivity Investigation of Multi-walled Carbon Nanotube-filled Composite Nanofibres

There is a growing interest in carbon nanofibre materials especially for applications that require high surface area, excellent chemical inertness, and good electrical conductivity. However, in certain applications a much higher electric conductivity is required before one can take the full advantage of the nanofibre network. Therefore, incorporating superconductive materials such carbon nanotubes is thought to be a feasible approach to enhance the electrical properties of the carbon nanofibres. The objectives of this study were to prepare and characterize multi-walled carbon nanotube-filled composite nanofibres. Carbon nanofibres were produced via electrospinning technique using precursor solutions of polyacrylonitrile in dimethylformamide loaded with different amount of multi-walled carbon nanotubes (MWCNT). The electrospun fibre samples were then pyrolyzed in a nitrogen-filled laboratory tube furnace. Characterization process was performed using scanning electron microscope (SEM), transmission electron microscope (TEM), and four-point probe method. It was found that the incorporation of MWCNT into the carbon nanofibre structures could significantly increase the electric properties of the nanofibres. The composite nanofibres with 0.1 wt.% of MWCNT loading has the highest electrical conductivity of 155.90 S/cm compared to just 10.71 S/cm of the pure carbon nanofibres. However, the electrical conductivity of the composite fibres reduced drastically when higher weight percentages of MWCNT were used. This was caused by agglomeration of MWCNT causing premature percolation, and broken fibre network as evidenced by SEM and TEM examinations. The results obtained from this study may facilitate improvements in the development of superconductive high surface area materials for electronic applications

The Effect of Deposition Time on Filtration Efficiency of Electrospun Nanofibre Water Filters

Growing concern over turbidity of river waters due to high presence of solid suspensions has encouraged the development of new type of efficient water filters. In this study, a new type of water filter was developed by incorporating electrospun nanofibres. The relationship between the amount of incorporated nanofibres in term of deposition time and filtration efficiency was studied. Nylon 6 solution at 20 wt.% concentration was electrospun onto standard glass fibre filters. A high voltage of 14 kV was supplied at the spinneret and electrospinning distance was set at 10 cm. Suspended solid retention test was conducted on the glass fibre filters using a vacuum filtration system based on BS EN 872 standard. The morphology of the filters was studied using scanning electron microscopy and ImageJ software. From the results, the suspended solid retention capability increased linearly with nanofibre deposition time. Due to small size of the nanofibres, the addition of nanofibre layer has increased the total porosity of the filter. Findings from this study could open up further understanding in new generation of water filters