A review of grouper (Epinephelus suillus) fry production research in Malaysia

Research on grouper (Epinephelus suillus) fry production in captivity has been carried out in Malaysia since 1986 at Tanjung Demong Marine Finfish Production and Research Centre (TDMFPRC) but the breakthrough was only achieved four years later in 1990. Eggs were obtained through natural and induced spawning in tanks. Natural spawning of grouper in captivity seldom occurred and was unpredictable. However induced spawnings were successfully carried out by injecting human chorionic gonadotropin (hCG) intramuscularly at a dose of 500-1000 IU/kg fish. The results from several trials on larval rearing conducted since 1989 until recently showed that larvae obtained from natural spawnings survived longer with some reaching the juvenile stage. The highest recorded survival rate of 43 days posthatch (32.5 mm total length) was 12.1% at 28-32 °C water temperature. On the other hand, 100% mortality usually occurred in larvae obtained from induced spawning 7 days after hatching. The major constraints of grouper fry production in Malaysia are lack of male spawners, inconsistent and unpredictable natural spawning, small quantity of eggs released every spawning day, poor fertilization and hatching rate, weak hatchlings, and high mortality rate at the early stages of larval development. The latter is probably due mainly to problems on initial feeding

Effect of waste plaster of Paris on physical and mechanical properties of ceramic pottery body

Over the years, millions tonnes of waste plaster of Paris (POP) were generated and disposed in landfills or most of the time was dumped directly into the environment without any treatments, makes it as one of the environmental issues. Therefore, a new alternative is required to convert the wastes POP into useful materials and marketable to minimize the environmental impact. In the early stage, this study focused on the characterization of the raw material used through particle size analysis, thermal analysis, and identification of its purity. Then, the slip casting technique and standard American Society for Test and Materials (ASTM) was respectively used to fabricate and characterize all of the pottery samples. In the second stage, the ceramic pottery body was fabricated using different composition of waste POP, started from 0 wt.% until 12 wt.%. The samples obtained were analysed through viscosity test and its green body was observed. The results showed that the samples with compositions of 0 to 10 wt.% of waste POP were the only samples that can be used in this study. The analysis on the effects of particle sizes ranging from 25 to 73 μm and sintering temperatures ranging from 950 to 1050 °C on the physical and mechanical properties of the fabricated ceramic pottery body, respectively, were then determined in the third and fourth stage of this study. The physical properties were reported in terms of shrinkage, porosity, and density values; whereas, the mechanical properties were reported in terms of the value of modulus of rupture (MOR). The result showed that a dense and a high strength of ceramic pottery can be produced by using a finer size of particle of 25 μm and at a high sintering temperature of 1050 °C, based on the low porosity value, the high density value, MOR and also the controllable value of shrinkage. Therefore, it can be concluded that the waste POP can be successfully used as a filler to enhance the properties of ceramic pottery body

Transmission properties of acousto optic material

Laser beam can be modulated by acousto optic modulator using a suitable acousto optic material. UV-VIS Spectrophotometer was utilized to investigate the transmission spectrum of two non linear acousto optic materials that are lithium niobate and fused quartz. From the spectrum it shows that transmittance for fused quartz and lithium niobate were 90% and 68% respectively. The absorption coefficient ? is calculated and plotted versus photon energy. It was found that ? increases linearly with photon energy in the range of 3.50 eV to 4.0 eV for fused quartz and 3.15 eV to 4.0 eV for lithium niobate. The estimated optical energy band gap was 2.97 eV for lithium niobate and 3.69 for fused quartz. From the transmission properties obtained in this study, it can be summarized that fused quartz is a better choice to be an acousto optic material

Effect of waste plaster of Paris on physical and mechanical properties of ceramic pottery body

Over the years, millions tonnes of waste plaster of Paris (POP) were generated and disposed in landfills or most of the time was dumped directly into the environment without any treatments, makes it as one of the environmental issues. Therefore, a new alternative is required to convert the wastes POP into useful materials and marketable to minimize the environmental impact. In the early stage, this study focused on the characterization of the raw material used through particle size analysis, thermal analysis, and identification of its purity. Then, the slip casting technique and standard American Society for Test and Materials (ASTM) was respectively used to fabricate and characterize all of the pottery samples. In the second stage, the ceramic pottery body was fabricated using different composition of waste POP, started from 0 wt.% until 12 wt.%. The samples obtained were analysed through viscosity test and its green body was observed. The results showed that the samples with compositions of 0 to 10 wt.% of waste POP were the only samples that can be used in this study. The analysis on the effects of particle sizes ranging from 25 to 73 μm and sintering temperatures ranging from 950 to 1050 °C on the physical and mechanical properties of the fabricated ceramic pottery body, respectively, were then determined in the third and fourth stage of this study. The physical properties were reported in terms of shrinkage, porosity, and density values; whereas, the mechanical properties were reported in terms of the value of modulus of rupture (MOR). The result showed that a dense and a high strength of ceramic pottery can be produced by using a finer size of particle of 25 μm and at a high sintering temperature of 1050 °C, based on the low porosity value, the high density value, MOR and also the controllable value of shrinkage. Therefore, it can be concluded that the waste POP can be successfully used as a filler to enhance the properties of ceramic pottery body

Hubungan di antara status Sosio Ekonomi (SSE) keluarga dengan pencapaian akademk : satu kajian ke at as pelajar aliran teknikal di Sekolah Menengah Teknik Negeri Sembilan

Kajian ini bertujuan untuk melihat hubungan di antara status sosio ekonomi (SSE) keluarga dengan pencapaian akademik di kalangan pelajar aliran teknikal. Kajian ini dijalankan ke atas pelajar tingkatan empat aliran teknikal di lima buah Sekolah Menengah Teknik di Negeri Sembilan iaitu Sekolah Menengah Teknik Tuanku Jaafar, Sekolah Menengah Teknik Juasseh, Sekolah Menengah Teknik Pertanian Rembau, Sekolah Menengah Teknik Ampangan dan Sekolah Menengah Teknik Port Dicksoa Seramai 350 orang pelajar terlibat dalam kajian ini dan dipilih secara rawak mudah. Analisis regresi mudah dan regresi berbilang digunakan untuk melihat hubungan di antara pembolehubah yang dikaji. Keseluruhan data kajian telah dianahsis menggunakan perisian Statistical Packages for the Social Sciences (SPSS) versi 11.5 dengan membuat pengiraan peratusan dan regresi. Dapatan kajian menunjukkan secara majoritinya, SSE mempunyai hubungan yang signifikan dengan tahap pencapaian akademik pelajar. Dengan itu dapat dirumuskan bahawa SSE mempengaruhi tahap pencapaian akademik pelajar aliran teknikal. Beberapa cadangan dikemukakan untuk panduan kajian selanjutnya

Geometry optimization of dry ice blasting nozzle for the noise reduction using experimental validation

Dry ice blasting provides many advantages to surface cleaning in which the blasting medium sublimate during the surface impact will not leave a secondary contamination. However, on the negative side of dry ice blasting (DIB), it produces a high noise exposure. The noise exposure during a high blasting pressure may reach up to 130 dB which is considered a harmful noise level (standard 90 dB for eight working hours per day). At present, safety measures are taken according to administrative control that encapsulates the whole system with sound insulation. This limitation has made this research work a significant contribution to dry ice blasting industry. The main objectives of this project are to examine the dry ice blasting’s flow characteristic on the influence of noise emission and to establish optimum parameters affecting the acoustic noise emission. The experimental validation on the effect of impact force and noise emission for optimum nozzle design is investigated. ANSYS fluent version 18.2 is employed in this study to simulate the fluid flow and acoustic noise in the nozzle. Six (6) different nozzle geometries are analyzed namely divergent length, convergent diameter, expansion ratio, gas inlet diameter, length ratio, and particle inlet angle. The optimum nozzle geometry is fabricated and validated throughout the experimental study on the effect of the impact force and sound pressure level for different pressures. The result shows that the optimum DIB nozzle geometry that satisfy the research objectives for gas inlet length, convergent diameter, particle inlet angle, divergent length, convergent length, gas inlet diameter, expansion ratio are 36 mm, 35 mm, 50°, 230 mm, 45mm, 6 mm and 1.00 respectively. This research is expected to provide a novelty design of dib nozzle geometry that able to protect the society from the hazardous working environment by engineering control

The characterization of mechanical behaviour on kenaf fibre / polypropylene composites

Global demand for wood plastic composite (WPC) has increased due to the increase of population and latest applications primarily in Malaysia industry today such as decking, chair and ceiling. However, the current WPC is worth investigating since such materials can be explored by enhancing their strength and quality through the treatment method. The objective of this study is to identify the effect of alkaline treatment on kenaf fibre in WPC system, to investigate the highest strength of kenaf fibre loading on mechanical properties in WPC, and to evaluate the morphology characteristics from fracture specimens related to the mechanical testing via scanning electron microscopy (SEM). Specimen was fabricated via injection moulding and hydraulic hot press using kenaf fibre (KF) as filler and polypropylene (PP) as the matrix. A tensile test was carried out to determine the tensile stress of the material. The result revealed treated specimen possesses high tensile stress at 5 wt.% sodium hydroxide (NaOH) compared to 10 wt.% and 20 wt.%. The optimum tensile stress was at 40 wt.% KF (5 wt.% NaOH, 5 wt.% MAPP) with the value 21.38 MPa. Flexural test was carried out on untreated and treated KF which is pure PP, 10 wt.% KF, and 20 wt.% KF by weight to PP. The result of flexural stress showed treated specimen lead better flexural at 20 wt.% PP/KF (5 wt.% NaOH) with 30.25 MPa. Meanwhile 40 wt.% KF (5 wt.% MAPP) give high fatigue life cycles at all stress level 90 %, 80 %, 70 %, 60 % and 50 % as the specimen structure less damage was induced during fatigue test. SEM is used to observe the morphological characteristics of PP/KF. The good interfacial bonding between KF and PP is 5 wt.% NaOH due of less impurities and lignin content. Overall 5 wt. % NaOH with 40 wt.% PP/KF (5 wt.% MAPP) showed the best result and it is worth to replace the current kenaf fibre polymer composites product

Xylene isomerization over zeolite catalysts

Paraxylene is used as a raw material for the production of the synthetic fibers. The production of paraxylene can be obtained by isomerization of xylene using zeolites as catalyst. At equilibrium, the mixture of xylene contains 24% para, 24% ortho and 52% of metaxylene. The objective of this experiment is to access the effectiveness of several zeolite catalysts for the isomerization of xylene. The study was carried out using micro reactor packed with zeolite (0.5g). In this work, the activity and selectivity of the catalyst in the isomerization of xylene depend on the type of zeolite used. HZSM-5 catalyst gives higher activity and selectivity over other type of zeolite