Proposed Testing Quality Of Silicon Nitride In Nuclear Application By Ceramography

The components in nuclear  application should ensure the safety during operation. Testing and investigation should be performed to ensure the quality of every component. This report propose ceramography technique for testing of silicon nitride in nuclear application. Ceramic material is known brittle therefore not possible to hold by using vice as usual used in metal during cutting. Since ceramic is very hard, the cost for cutting, grinding and polishing required high cost due to utilization of diamond. Special techniques should be employed during observation bay using optical microscope because ceramic are not reflect the light. Ceramic is mainly known since their high chemical resistance therefore difficult to etching by using chemical solution. A unique respond of ceramic due to indentation make the indentation technique become part of ceramography. Indentation process requires a flat sample in order valid result to be obtained, and this can be achieved by special technique during grinding and polishing. This research introduce of ceramography process that was successfully done on Si3N4, from preparation of the specimen, microstructure observation, the respond on indentation, strength, and porosity investigation   The results showed that the fluorescent dye penetrant under ultra violet source of light the defect in Si3N4 was easily observed therefore is suitable to be proposed as a technique for testing the quality of silicon nitride component in nuclear application.[P1]  [P1]The revised sentence and adde

ESTETIKA VISUAL DAN NONVISUALKOIN CINA KUNO ASLI YANG DITEMUKAN DI BALI DAN KOIN CINA BUATAN LOKAL

Up to now, Balinese culture and art cannot be separated from the utiliza- tion of old Chinese coins which local people in Bali call pis bolong. The use of those old Chinese coins in traditional ritual in Bali is found even from the infants until the end of that person’s life at cremation ceremony. The cremation ceremony uses the Chinese old coins to be burned with the deceased and to be sent with the ash from the burned deceased into the sea. This practice makes the number of old Chinese coins decrease meanwhile the demand of using the coins increase. The condition is worsened by the practice of using old Chinese coins as souvenirs. The local metal craftsmen have tried to solve the scarcity of the coins by producing a local-made Chinese coins and making them as similar as the original Chinese coins. However, due to the lack of local craftsmen’s aesthetics assessment visually and non-visually on old Chinese coins, their physical appearances were very much different from its original Chinese coins. Therefore, this paper presents the result of the observation of aesthetics  assessment  visually and non-visually on old Chinese coins that can be used as guidance to produce local-made old Chinese coins as similar as its original

ON INVESTIGATION OF TENSILE STRENGTH OF COMMERCIAL SYNTHETIC NON-ABSORBABLE SUTURE MADE FROM OF BLUE POLYPROPYLENE MONOFILAMENT

Objective: The purpose of this research is to investigate the tensile strength of commercial synthetic non-absorbable suture made from blue polypropylene monofilament that commonly used in surgery.Methods: The commercial synthetic non-absorbable made from blue polypropylene monofilament was prepared for this purpose. The ASTM C1557-03 was used as a standard the method for analysis. For accuracy of the measurement, the diameter of the sutures was measured using optical microscope. The tensile strength, strain at failure, and modulus elasticity of the sutures were measured following instruction from the standard test method. The graph strain versus stress was provided.Results: Results show that that the average tensile strength of five valid tested samples is about 875.812 MPa. The average strain is found about 0.282. The average of modulus of elasticity is 4026.069 MPa.Conclusion: It is concluded that the sutures of commercial synthetic non-absorbable suture made from blue polypropylene monofilament having linier elastic as well as plastic properties. The average tensile strength of five valid tested samples is about 875.812 MPa. The average strain at failure is found about 0.282. The average of modulus of elasticity is 4026.069 MPa

COMPARISON TENSILE STRENGTH OF NATURAL AND SYNTHETIC ABSORBABLE SUTURES

Objective: The aim of the investigation is to evaluate and to compare the tensile strength of commercial natural and synthetic absorbable suturematerials currently used in surgery. The natural absorbable sutures of chromic catgut are prepared for this purpose as well as commercial syntheticabsorbable sutures made from polyglycolide.Methods: The analysis has been carried out following the standard test method for tensile strength and Young’s modulus of fiber ASTM C1557-03.Measuring the diameter of each suture has been carried out with an optical microscope to determine the accuracy of manufacturers’ data. Tensiletesting has been performed to evaluate the tensile strength of each type of sutures. The modulus elasticity and strain (ϵ) obtained are also presented.Results: The results show that sutures made from braided synthetic material of polyglycolide (violet coated) present a tensile strength remarkablysuperior (1070.292 MPa) to that of natural absorbable sutures of chromic catgut (392.276 MPa). Using optical macro microscope analysis,monofilament sutures present less surface irregularities than multifilament polyglycolide sutures. Chromic catgut monofilament sutures present lesssurface irregularities than multifilament polyglycolide.Conclusion: Tensile test of absorbable sutures was conducted in this research. Two types of absorbable sutures were investigated and compared. It isfound that sutures made from braided synthetic material of polyglycolide (violet coated) having much better tensile strength comparing with suturesmade from natural material (chromic catgut monofilament)

EFFECT OF FEEDING WITH HERB OF ERYTHRINA VARIEGATA TO BIOCOMPATIBILITY OF THE COCOON FIBER OF WILD SILK MOTH ATTACUS ATLAS FOR FUTURE APPLICATION AS BIOCOMPATIBLE OF SILK SUTURES

Objectives: Silk is biocompatible as biomaterial and has been used commercially as sutures. More interesting properties of the silk are that the mechanical properties exceed all natural polymer and synthetic materials. In this research, a type of silk suture is being developed from species of Attacus atlas to obtain better biocompatible sutures. A. atlas is a species of silk moth that consume not only single types of leaves. The Quality of cocoon fiber then can be arranged base on the types of the leaves that is consumed. Better biocompatibility sutures comparing with recent commercial silk sutures which is not biocompatible, can be achieved by feeding with variety types of leaves. Silk suture that already established in the market is a base product of Bombyx mori species of silk which is only consume one type of leaf (mulberry leaves).Methods: In this research, the A. atlas cocoon was produced by feeding with herb Erythrina variegate. The microstructure was observed, element composition as well as biocompatibles properties was investigated.Results: A high composition of kalium (K) as well as chloride (Cl) is identified in the fiber. The released fiber from cocoon also indicates high biocompatibility that is promising as biocompatible suture.Conclusion: The biocompatible fiber for future application as sutures is possible to be prepared by feeding the wild silkworm of A. atlas with leaf of E. variegate. The fiber is found rich with kalium (K) as well as chloride (Cl) with irregular shape of crystal at the surface of the fiber

Sintesis Whisker Silikon Karbid Bagian I: Disintesis Dari Sekam Padi

ABSTRAK The purpose of this work is to synthesize whisker silicon carbide using rice hull from Indonesia. The rice hull was taken .from the area of Yogyakarta, Indonesia. The synthesis was started with coking the rice hull at 900"C for I hour without contact with air. After coking, the specimens was reacted at 1500"C in an electric furnace in argon atmosphere, the flow rate of argon flow was kept around 2 liter/min. The process was continued by treating the specimen in a boiling of MOH solution to separate the SIC whisker with the silica, and finally heating the specimen at 800°C to eliminate the excess of carbon. The final product was silicon carbide whisker in the form of long SiC whisker and a small part in the form of wool like SiC whisker Key words: Rice hull, long SiC whisker, wool-like SiC Whisker

Sintesis Whisker Silikon Karbid Bagian Ii: Disintesis Dari Serat Karbon Dan Silica Fume

ABSTRAK This work investigated the use of carbon fiber and silica fume as a source of raw material for the production of silicon carbide whisker. Carbon and silica fume as the starting materials in the ratio of 7:10 by weight, were mixed in a jar mill for 8 hour. This mixture was then charged in an alumina crucible and heated at 1500"C for 1 hour with a heating rate of 2"C/min. in argon atmosphere having flow rate of 2 liter/min. The product contained silicon carbide, silica, and excess carbon. To remove the residual carbon, the product was put in a furnace and heated at 900°C for 1 hour. Its silica contents was eliminated by dissolving it in a boiling NaOH solution. The final product was silicon carbide in the form of particulate, needle-like SiC whisker, wool-like SiC whisker, and long SiC whisker. Key words: SiC whisker, carbon fiber, silica fume

Arkeometalurgi pada Enam Jenis Logam yang Berpengaruh pada Peradaban Umat Manusia

ABSTRACT It is undeniable that the expertise on metal work influenced the culture of the human. It was proved by the naming of the age by using the name of the metal such as iron age and bronze age. Kebudayaan manusia sudah sejak lama secara konvensional dibagi menjadi tiga, berdasarkan bahan bahan yang digunakan untuk peralatan, khususnya sebagai alat potong. Dimulai dengan penggunaan batu yang dipecah dan diasah, atau tulang serta tanduk yang diruncingkan, yang selanjutnya disebut dengan zaman batu. Periode selanjutnya dimulai saat manusia menyadari bahwa sejenis batu yang mengandung unsur logam tembaga dapat dicairkan dalam keadaan panas, dituangkan ke dalam cetakan dan bentuknya sesuai cetakan saat sudah dingin, zaman ini disebut dengan zaman perunggu. Zaman setelah ditemukannya besi sebagai alat potong selanjutnya disebut dengan zaman besi (Childe 1930). Alat-alat musik perunggu yang dibuat pada zaman perunggu di Cina membantu menciptakan atmosfir, dimana para manusia dan dewa dapat berhubungan. Dengan memberi musik pada gerakan manusia dan memberi melodi pada perkataan yang diucapkan menyebabkan musik digunakan pada aktivitas ritual yang dapat memasuki dunia roh leluhur di surga. Pada zaman Cina kuno seni musik perunggu amatlah ditangani secara ketat. Seperti misalnya untuk lonceng (bell) dibuat dengan komposisi enam bagian tembaga dan satu bagian timah putih yang dikenal dengan istilah kaogongji. Namun tentunya karena perbedaan daerah sumber logam maka terdapat pula yang mengandung kandungan timah hitam. Khusus untuk pembuatan lonceng perunggu maka lonceng Cina biasanya mengandung timah putih antara 12% dan 16 % karena menghasilkan kekerasan yang optimum saat dipukul. Jika ditambahkan timah putih lebih dari 16 % maka akan cenderung getas dan muda

Characteristics and performance analysis of different grain sizes bamboo-activated carbons for motorcycle flue gas adsorption

The use of fossil fuels in human activities such as motorcycles has led to an increase in the concentration emitted in the atmosphere. Various efforts and methods such as adsorption using activated carbon have been developed and applied to reduce the emission. Therefore, this study focuses on the characteristics and performance of bamboo-activated carbons in the adsorption of motorcycle flue gases. This was carried out using different grain sizes (z) of activated carbons AC-M1, AC-M2, and AC-M3 for grain sizes of z≤250, 250<z≤420, and 420<z≤590 microns, respectively, which were derived from swat bamboo and carbonized at a temperature of 750 ○C. Furthermore, physical activation was applied by heating the charcoal at the same temperature under a nitrogen flow rate of 150 mL/min nitrogen. The Thermogravimetric (TGA), scanning electron microscopy (SEM), and adsorption isotherm tests were employed for the characterization of activated carbons. Additionally, the performances of activated carbons for motorcycle flue gas adsorption (CO2, CO, and HC) were carried out by a motorcycle emission test. According to the results, activated carbon AC-M1 produced the best characteristics and performance for adsorption of motorcycle flue gas, as it has a pore volume of 0.135 cm3/g, a specific surface area of 244.69 m2/g, and a nitrogen adsorption capacity of 87.047 cm3/g. These characteristics prove to have good adsorption efficiencies at 100 %, 87.30 %, and 100 % for adsorption of CO2, CO, and HC, respectively

Characteristics and performance analysis of activated carbons derived from different precursors and activators for waste water adsorption

Domestic waste such as methylene blue from the dyeing process and detergent from laundry activities are sources of water pollution. Before being dumped into the water, this waste must be minimized. One approach that can be utilized is the adsorption method with activated carbon. To generate activated carbon with the properties required for this purpose, an appropriate precursor and manufacturing conditions must be chosen. The objective of this research is to investigate the characteristics and performance of activated carbon derived from various precursors (Petung and Santong bamboos) and activators (Ar, N2, and CO2) for detergent and methylene blue dye adsorption. The difficulty to be solved is determining the best precursor and activator for maximum methyl blue and detergent adsorption. Characterizations included FTIR, XRD, SEM, TGA, and adsorption isotherm testing. The study's findings show that activated carbons have functional groups O-H (hydroxyl), C-H (aldehydes and alkenes), C=C aromatic rings, C-H aromatic groups, and an amorphous structure. The presence of a porous and amorphous structure, as well as the C=C aromatic ring, makes activated carbons capable of absorbing methyl blue and detergent. Santong bamboo-activated carbon activated with argon has the best characteristics and adsorption capability. This activated carbon has a fixed carbon content of 76.34 %, pore volumes of 0.362 cc/g, average pore widths of 1.967 nm, pore surface area of 291.487 m2/g, bimodal pore size distribution, and methylene blue and detergent adsorption capabilities of 19.733 cc/g and 1.689 cc/g, respectively. The results obtained are on a laboratory scale, which necessitates additional research, particularly on how to create reservoirs and regenerate activated carbon simply and affordabl