Modified palm oil fuel ash (pofa) as quartz replacement for the production of porcelain

Utilization of silica rich ash such as palm oil fuel ash (POFA) in the ceramic industry due to the increasing demand for porcelain with improved performance is inevitable. Wastes are produced from the industry in form of empty fruits bunches, kernel and fibers. Palm oil industries burned the waste to produce heat to the boiler and generate electricity, the ash produced is known as palm oil fuel ash. POFA has similar chemical property with quartz, thus can be used as quartz replacement. The objectives of this research are to modify POFA, determined its effect on physico-mechanical properties of porcelain and develop a formulation model. To remove the moisture of POFA, the powder was dried in an oven at 110 °C for 24 hours and ground to a sufficient fineness ≤ 50 μm for 12 hours at 250 rev/min. POFA powder underwent heat and HCL acid treatments. Standard porcelain of 50 % clay, 25 % feldspar and 25 % quartz was adopted. Quartz was substituted with POFA at 0, 15, 20 and 25 wt.% and mixed homogeneously with the composition of porcelain, dry pressed into pallets at 91 MPa and sintered at 1100 °C, 1150 °C, 1200 °C and 1250 °C for 2 hours soaking time. Modified POFA (SiO2, Al2O3, Fe2O3, MgO, CaO, and P2O5) were then added to the optimum composition (1150 °C, 15 wt.% of POFA and 2 molar HCl acid treatment) at 1, 2, 3, 4, 5, 10 and 15 wt. % mixed homogeneously, dry pressed and sintered at 1150 °C to identify their effect on physico-mechanical properties of porcelain. Densification was achieved at lower sintering temperature by addition of POFA. Due to formation of mullite and crystalline phase, the highest values of bulk density, compressive strength, and Vickers micro hardness were found to increase by addition of Fe2O3 at 5 wt. % as 2.515 g/cm3, 177.08 MPa and 829 HV respectively. The results of developed polynomial regression models show a very good prediction similar to the experimental value. Hence, POFA has a greater future in ceramic industry due to its flexibility and chemical properties. It is therefore evidently concluded that, addition of Fe2O3 at 5 wt. % enhanced both physical and mechanical properties of porcelain

Preparation and characterization of PMMA-AgNPs polymer composite as a dental prosthesis

Silver nanoparticles (AgNPs) have been used for centuries in the field of medicine due to the antimicrobial properties. AgNPs has been synthesized and incorporated in different aspects of biomaterials. It is reported that AgNPs as a result of its small size, it provides sufficient antimicrobial effect at lower filler level, thus can be used in dentistry for prevention and reduction of biofilm formation on a surfaces of dental prosthesis. The purpose of this study is to develop AgNPs antimicrobial acrylic resin for dental prosthesis. The effect of AgNPs incorporated into acrylic resin poly methyl methacrylate (PMMA) on the bacterial biofilm was studied in terms of bacterial growth and the incorporating effect on the thermal stability of these polymeric biocides was evaluated. Silver nanoparticles in colloidal form was added to PMMA(ONDA-CRYL) using microwave and make four dental prosthesis at the different concentration. The specimens were delivered to the four toothless patients for 21 days. The formed biofilm was tested for microbiological study (taxonomic profile). After setting, the specimens were characterized to determine the spatial distribution of AgNPs on the PMMA matrix through scanning electron microscope and the thermal stability was examined using TGA and DSC. The modified PMMA prosthesis base containing AgNPs, which exhibited good in vivo antimicrobial properties without altering their thermal properties of degradation as well as their mechanical properties and minimize the maximum infectious signs by reducing the formation of microbial biofilm forming on the surfaces of dental prostheses. As the modification of PMMA with AgNPs improved the anti-biofilm properties without altering its mechanical and thermals properties to the degradation, it could be used as a dental prosthesis

Physical and Mechanical Properties of Porcelain Formed by Substituting Quartz with HCl Treated Palm Oil Fuel Ash

Palm Oil Fuel Ash (POFA), is a waste material from palm oil industries that has potential of recycling in the porcelain production due to its high content of silica. POFA is produced by burning palm oil shells, empty fruit branches and fibers as a fuel to heat up the boiler for electricity generation in the industries. This research is aimed at producing porcelain with the substitution of treated POFA with quartz at 20 wt%. Treated POFA was dried in an oven for 24 hours at 110°C and ground using ball mill machine for 12 hours to get particle size ˂50µm. 20 wt% of POFA powder was substituted for quartz and mixed with the composition of porcelain for 12 hours and then pressed into pellets at a mold pressure of 91 MPa. The pellets were sintered at a temperature of 1200°C for 2 hours soaking time at a heating rate of 5°C per minute. It was revealed that the maximum density was achieved at 2.38g/cm3 as the molarity of HCl is increased to 3 mole with the counterpart hardness of 7826 MPa. This improvement may be attributed to the increased in the silica content as a result of treatment of POFA with HCl acid

Evaluation of Computed Tomography doses in three medical diagnostic centres in Kano

Computed tomography (CT), is an X-ray procedure that generates high quality cross-sectional images of the body, and by comparison to other radiological diagnosis, the use of CT in medical diagnosis delivers radiation doses to patients that are higher than those from other radiological procedures. Lack of optimized protocols could be an additional source of increased dose in developing countries. The aim of this study is to conduct radiation doses survey for head, chest and abdomen CT examinations of patients in three selected CT Diagnostics centers in Kano city. Detailed were obtained for 144 CT examinations for adults patients only. The results from the three Diagnostics centers (hospitals) were compared within each other as well as with the IAEA guidance level for this particular investigation.  Survey of radiation doses were carried out by calculating Volume dose index (CTDIvol), and dose length product (DLP) using the SPSS software program. The study showed that the mean DLP of the one Diagnostics centers (hospital) is 1522.6 mGy.cm which is far much higher than the two other diagnostic centers Mohammed Abdullahi Wase which stands at 661.0 mGy.cm, Providian medical diagnostic center which stand at1121.3 mGy.cm as well as higher than the IAEA level which is 527 mGy.cm.The study showed that the mean CTDIvol for patients in AKTH is 38.6 mGy which again is higher than the two other diagnostic centers Mohammed Addullahi Wase which is 9.5 mGy, Providian medical diagnostic center is 9.6 mGy though, it is less than the IAEA level which is 47.0 mGy.This study showed that there is an urgent need for optimizing patient doses in Kano city CT examinations. This can be ensured by providing training and retraining for workers and conducting quality control measurements and preventive maintenance regularly so as to detect any unnecessary outflow of ionization radiation early enough before they negatively affect the image which may necessitate re-imaging and then increase patients’ dose

Influence of different compositions of fly ash as fluxing agent in porcelain

Fly ash is alumina-silica waste products from the combustion of palm fiber and shells in the boiler which are collected at the multi-cyclone collectors where almost 3 million tonnes per annum being produced in palm oil industry in Malaysia. The aim of this paper is to investigate the replacement of feldspar by fly ash as potential fluxing agent in triaxial porcelain. Clay, feldspar, quartz and fly ash were mixed for 12 hours, pressed into pellets and sintered at 1250 ºC. The samples were measured according to the physical and mechanical properties. Microstructure study was done through SEM analysis. The optimum composition of fly ash was observed at 5 wt.% where the maximum compressive strength was achieved at 105.04 MPa and shows the decreasing results in volume shrinkage. SEM study shows intense interlocking between the primary and secondary mullite needles in glassy matrix which contribute in improving the strength of the porcelain at this composition. Therefore the substitution of fly ash is suitable as a fluxing agent in porcelain that improved its physical and mechanical properties

Effect of Mmolarity of HCl on production of Silica (SiO2) from Palm Oil Fuel Ash (POFA)

Palm oil fuels ash (POFA) is a by-product from palm oil industries that constitutes of different compounds such as silica (SiO2), alumina (Al2O3) and many others, its abundances and improper disposal in waterways and as a landfill cause environmental pollution and hence need for its modification and usage. This paper presents an alternative way of producing silica from POFA. Untreated POFA was dried in an oven for 24 hours at a temperature of 110 °C and ground in a ball mill machine for 12 hours at a speed of 250 rev/s. After sieving, the powder was dispersed in 1 mole, 2 mole and 3 mole of HCl. An increase in the composition of SiO2 was observed using X-ray Fluorescence (XRF) analysis due to the increase in the molarity of acid, X-ray Diffraction analysis (XRD) and Scanning Electron Microscopy (SEM) shows that POFA has a crystalline and porous cellular structure. This shows that acidic wash treatment is good and an improved method for the production of silica from POF

An Improved Method for Production of Silica (SiO2) from Palm Oil Fuel Ash (POFA) using Acidic Wash Treatment (HCl)

Palm oil is derived from tropical palm tree that is easily cultivated in tropical countries like Malaysia, Thailand and Brazil. Palm oil fuel ash (POFA) is a by-product from palm oil industry that is produced in large quantity (approximately 4 million tons annually in Malaysia). This paper presents an improved method for production of silica from POFA. Untreated POFA was dried in an oven at 110 ºC for 24hours, it was then grinded in a ball mill for 12 hours at 250 rev/min to reduce the particle size, the powder is dispersed in 1 molar of HCl acid and stirred constantly for 30 min using electric shaker. X-ray fluorescence analysis shows that, POFA treated with acid shows the existence of thirteen chemical elements and the chemical composition of SiO2 increases after the acidic wash from 15.90 wt% to 43.70 wt%. The percentage difference for SiO2 is shown to be 175%. Based on the result of this study, it can be concluded that acid wash treatment is suitable for production of silica from POFA

Photoelectrode nanostructure dye-sensitized solar cell

This study used carica papaya (pawpaw leaf) extracts as natural organic dye for dye sensitized solar cell (DSSC). Pawpaw leaf extract is rich in chlorophyll and was extracted using ethanol as the extracting solvent and serve as the sensitizer for DSSC. The specialty of the DSSC relative to other types of solar cells is the use of the dye. In addition, the self-developed photoelectrode nanostructure TiO2 with an average particle size of 50 nm was synthesized through solution chemistry techniques and deposited on the fluorine doped tin oxide (FTO) glass substrate using screen printing procedure, forming a TiO2 thin film of 12 μm thicknesses. This TiO2 thin film underwent sintering at 450 °C to enhance the compactness of the film before impregnation into the dye solutions. This study further investigated the photoelectric conversion efficiency and the fill factor of the encapsulated DSSC. The experimental results show conversion efficiency of 0.030 % with fill factor of 0.5867, short circuit current density (ISc) of 15.7325 mA/cm and open circuit voltage (Voc) of 0.5248 V. The photoelectrochemical performance of this extract demonstrated to be used as future alternative to application in solar cell.Keywords: Carica papaya; dye-sensitized solar cell; photoelectrode; conversion efficiency; fill facto

Biodiesel production from castor oil and analysis of its physical properties

Biodiesel is a biodegradable, renewable energy and efficient substitution fuel which can fulfill energy security needs without sacrificing engine performance. Biodiesel fuels were prepared from vegetable oil of castor beans and its physical properties such as viscosity, flash point and pour point were studied. The crude castor oil was purified and trans-esterified. Transesterification reaction is most widely used method for biodiesel production, in which the triglycerides in the oil reacts with monohydric alcohol. 200 ml of the castor oil was measured and pre-heated to 70 oC using hot magnet stirrer with thermometer. 1.5 ml citric acid was added to the heated oil sample and continuously stirred for 15 minutes at 70 oC. 4g of 8 % KOH was then added to the oil and continuously heated and stirred for 15 minutes at 70 oC. The mixture was then transferred to the vacuum oven where it was heated at 85 oC for 30 minutes. Similarly, 2g of silicon reagent was added while it was being heated and stirred. after 30 minutes the temperature was increased to 85 oC and 4g of activated carbon was added to each 100 ml of the oil sample, heated and stirred for 30 minutes and the mixture was separated using filter paper. At 30, 60 and 90 oC, the viscosity of crude, purified and transesterified castor oil were found to be (64, 52, 50 mpa.s), (47, 43, 37 mpa.s) and (38, 35 and 30 mpa.s) respectively. This shows that, trans-esterified castor oil has viscosities within similar range with the crude biodiesel oil for all the varying temperatures, indicating that viscosity is major reason why oils and fats are trans-esterified to biodiesel

Physico-mechanical properties of porcelain by substitution of quartz with POFA Treated with 2M Hcl acid

Palm oil fuel ash (POFA) is a by-product from thermal power plant where palm kernel, shell and fibre used as fuel to generate electricity and disposed with no economic value. POFA is used as quartz replacement in the production of porcelain. POFA was dried in an oven for 24 hours at 110 °C, ground at a speed of 250 rev/sec for 12 hrs. Some of the POFA amount was treated with 2 Molar of HCl acid and some was kept untreated. Both treated and untreated were substituted with quartz at 15 wt% and mixed with porcelain composition and dry pressed into pellets at a mould pressure of 91 MPa and sintered at 1150 °C, 1200 °C and 1250 °C for 2 hrs soaking time respectively. XRF revealed that, POFA has similar chemical composition with quartz. The highest compressive strength, bulk density and Vickers microhardness being achieved at sintering temperature of 1150 °C using treated sample with the values 169 MPa, 2.432 g/cm3 and 774 HV respectively. HCl treated POFA is a good candidate for quartz replacement and 1150 °C was the best sintering temperature