The material of composite hybrid Al / (SiCw + Al2O3) is a mixture of fine aluminium powder as a matrix while Silicon Carbide whiskers (SiCw) and Alumina (Al2O3) as reinforcement. Powder metallurgy method is used to manufacture composites according to the form of test specimens. Testing without treatment and after sintering treatment with temperature parameters and sintering time of 500 and 600°C at holding time 6 hours. This research was conducted to know the properties of thermal conductivity, hardness, density and SEM analysis after sintering process. The results show that the sintering process that has been carried out can provide a percentage increase and affect the composite properties. Improved thermal, hardness and density occurs due to stronger or denser interface bonds between the matrix and reinforcement influenced by increasing sintering temperatures, so sintering processes can affect composites on physical and mechanical properties.
The purpose of this study is to investigate of sound absorption of coconut filter fiber composites. The research material made with coconut filter fiber as reinforcement and matrix resin unsaturated polyester (UPRs) type Yukalac BQTN 157 with 1% hardener types MEKPO (Methyl Ethyl Ketone Peroxide) and fiber treatment by 0,5% KMnO4. Production methods is poltrusion and the variations of fiber volume fraction are 20, 25 and 30% and fiber length are 5, 10 and 15 mm. Testing of sound absorption frequency are 250, 500, 1000, 2000 and 4000 Hz. The results of research show that the highest value of sound absorption coefficient is on the composites with composition of 10 mm fiber length and 30% fiber volume fraction, that is 0.550828. The values are included in the class “Sound Absorption Coefficient Class D (Extremely absorbing)” with the range 0.40 – 0.60 based on ISO standard 11654:1997.
Activated carbon is a multipurpose material due to its unique properties such as high surface area and pore volume. The reduced carbon source from coal has led to the development of activated carbon from lignocellulosic material. However, there is limited literature reported the use of swat bamboo (Gigantocholoa verticillata) as an activated carbon precursor. In this research, swat bamboo has been converted to activated carbons under different carbonization temperatures of 550, 650, and 750OC and activation durations of 1.5 and 2 h. The results show that at activation time of 1.5 h, increasing carbonization temperature affecting the higher pore volume and surface area gained. The optimal characteristics of activated carbon were obtained at a carbonization temperature of 750OC and activation time of 1.5 h. This due to the activated carbon produced in this condition has the highest pore volume, surface area, and adsorption capacity of 0.138 cm3/g, 135.30 m2/g, and 95.776 cm3/g, respectively. Its average pore diameter was 2.053 nm with fix carbon of 75.26% and C of 76.79%. It has a monomodal pore size distribution with the highest adsorption of 0.056 cm3/g/nm occurred at a pore size of 1.516 nm.
The aim of the research to develop Internal and External Enviromental Strategies that can be applied for Primary Naval Cooperative Institutions company (PNCI). By using the SWOT matrix and Quantitative Strategic Planning Matrix (QSPM), alternative strategies in getting that maintains the image of PNCI company, facilities PNCI, maintaining the quality and service of products to attract consumers, increase the ability of management and cooperation for the purpose PNCI, service delivery order for consumers, utilizing technological advances to Enviromental, serving the lower middle market segment by providing a package and a special portion, and maintaining good relationships with suppliers or the surrounding area.
Pack carburizing merupakan suatu proses laku panas untuk memperoleh pengerasan hanya pada bagian permukaan dengan menggunakan media carburizer padat. Dengan memberikan temperatur pemanasan dan waktu penahanan yang tepat diharapkan dapat meningkatkan umur lelah suatu material baja St.42. Metode pada penelitian ini mengunakan pack carburizing padat berupa serbuk, yang dibuat dalam bentuk kotak dan didalamnya diisi serbuk carbon. Penelitian ini membahas tentang pengaruh waktu penahanan dan temperatur pack carburizing terhadap umur lelah baja ST 42 dengan menggunakan variasi temperatur pemanasan adalah : 850, 900 dan 950°C dan waktu penahanan 4, 6 dan 8 jam. Kedua variabel ini diamati pengaruhnya terhadap umur lelah. Berdasarkan hasil penelitian bahwa waktu penahanan dan temperatur pack carburizing berpengaruh nyata terhadap umur lelah, dimana umur lelah tertinggi yaitu pada 993.089 cycle pada temperatur pemanasan 950 °C dan waktu penahanan 8 jam. Umur lelah paling rendah adalah 440.613 cycle terjadi pada temperatur pemanasan 850 °C dan waktu penahanan 4 jam. Pack carburizing is a hot-selling process to obtain only hardening on the surface by using solid carburizer media. Providing proper heating temperature and retention time is expected to increase the fatigue life of a steel material of St.42. The method in this study using a solid pack carburizing of powder, which is made in the form of a box and inside it is filled with carbon powder. This study discusses the effect of detention time and pack carburizing temperature on ST 42 fat age by using variation of heating temperature are: 850, 900 and 950?C and holding time 4, 6 and 8 hours. Both of these variables were observed to influence the fatigue life. Based on the result of research that the holding time and temperature of pack carburizing have a significant effect on fatigue life, where the highest fatigue age is 993,089 cycles at heating temperature 950 ?C and 8 hours of detention time. The lowest fatigue period was 440,613 cycles occurring at a heating temperature of 850 ?C and a 4 hour detention time.
This research is concerned with the effect of different carburizers on hardness distribution, effective case depth and microstructure of low carbon steel after pack carburizing process. Carburizers to be used were combination of energizer (BaCO3), goat bone charcoal and bamboo charcoal with five different compositions. The specimens were heated to temperature of 950°C, soaked at the temperature for 4 hours and quenched in the water. After the process, microstructures of specimen were observed, the hardness was measured using Vikers method and effective case depths were calculated. The results obtained showed that for all types of carburizer used, the hardness were scattered from surface to the core with lower hardness level. Carburizer composition of 20% BaCO3 + 80% goat bone charcoal produced the highest hardness ( 789.273 HV1) at 0.2 mm from the surface, however, it yielded the lowest effective case depth (0.52 mm). The highest effective case depth of 1 mm was obtained using carburizer composition of 20% BaCO3 + 60% goat bone charcoal + 20% bamboo charcoal. Meanwhile, the original structures of raw material which consist of ferrite and pearlite transformed to hard martensite constituent in the surface after pack carburizing.
Activated carbon (AC) has an important role in many life fields. It has high porosity and very useful for gas mixtures separation and purification of air and water. Every application requires specific properties of AC. Characteristics of AC are strongly influenced by raw material and parameters of manufacturing process. This paper is focused to characterize of activated carbons (ACs) derived from swat bamboo (Gigantochloa verticillata) which is manufactured under different carbonization temperatures. Prepared samples of swat bamboo were carbonized by heating variations of 550, 650 and 750°C and held at such temperature for 1 hour. Char yielded is powdered and meshed to maximum grain size of 250 um and then physically activated by heating up to 800°C, held for 1 hour by flowing of 150 mL / min nitrogen. The results show that there was an increase in fix carbon and carbon contents from raw material to char and from char to ACs yielded; there were a little bit increase of fix carbon and carbon contents proportional to increasing of carbonization temperature. The maximum fix carbon (74.73%) and C (75.52) were obtained at carbonization temperature of 750°C. SEM observation showed that there has been a change in the morphology microstructure from raw material to activated carbons, wherein the ACs the pores structures clearly can be observed.
Proses pelapisan krom keras merupakan proses akhir atau tahap penyelesaian pada kebanyakan pembuatan komponen agar tidak cepat aus, seperti pada poros, pasak, ring piston, silinder, bearing dan crank shaf. Dalam bidang industri sifat mekanik yang banyak diperlukan pada logam yang dipergunakan adalah kemampuannya untuk tahan aus dan tahan korosi yang mana kita ketahui logam mempunyai reaksi yang sangat aktif terhadap perubahaan temperatur dan cuaca, maka perlu dilakukan pelapisan sehingga kemungkinan suatu bahan logam terkena korosi bisa dihambat. Bahan spesimen yang di gunakan adalah Baja St 60 (C 0.40%; Mn 7%; Si 0.28%; P+S 0.09%; Fe 98,53%) dengan variasi tegangan listrik: 4, 6, dan 8 volt, untuk variasi waktu elektroplating krom keras 30, 45, dan 60 menit. Pengujian yang dilakukan dengan pengukuran ketebalan lapisan menggunakan skala foto mikro dan menghitung ketebalan lapisan permukaan. Hasil penelitian menunjukkan bahwa semakin tinggi tegangan listrik yang digunakan dan semakin lama waktu proses pelapisan krom keras maka meningkat ketebalan lapisannya. Ketebalan lapisan permukaan yang paling tebal didapatkan pada tegangan 8 volt dengan waktu pelapisan 60 menit dengan ketebalan lapisannya sebesar 89,37 ?m, sedangkan ketebalan lapisan permukaan tipis didapat pada tegangan 4 volt dengan waktu pelapisan 30 menit ketebalan lapisannya sebesar 20,18 ?m. Jadi tegangan listrik dan waktu electroplating dapat mempengaruhi dan memberikan efek terhadap ketebalan lapisan yang terjadi pada Baja St.60. The hard chrome coating process is the final process or completion stage in most parts making so as not to wear out quickly, such as on the shaft, pegs, piston rings, cylinders, bearings and crank shafts. In the industrial field of mechanical properties that are much needed in the metal used is its ability to withstand wear and corrosion resistance which we know metals have a very active reaction to changes in temperature and weather, coating is necessary so that the possibility of a metal being corroded can be inhibited. The specimens used were Baja St 60 (C 0.40%; Mn 7%; Si 0.28%; P + S 0.09%; Fe 98.53%) with variations in electrical voltage: 4, 6 and 8 volts, for time variations hard chrome electroplating 30, 60 and 90 minutes. Tests carried out by measuring the thickness of the layer use a micro photo scale and calculate the thickness of the surface layer. The results showed that the higher the voltage used and the longer the coating process was hard chrome, the thickness of the layer increased. The thickest surface layer thickness was obtained at 8 volts with a coating time of 60 minutes with a layer thickness of 89.37 ?m, while the thickness of the thin surface layer was obtained at a voltage of 4 volts with a coating time of 30 minutes layer thickness of 20.18 ?m. So the electrical voltage and time of electroplating can affect and give effect to the thickness of the coating that occurs in Steel St.60
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