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"Untuk mengetahui pengaruh Cu dan Zn terhadap paduan Al-Si-Mg maka dibuat Sampel I dan Sampel II. Sampel I paduan Al-Si-Mg dengan variasi persen berat (%wt) Cu sebesar : 0 ; 1,5 ; 3 dan 5 %wt sedang Zn dibuat konstan sebesar 1 %wt. Sampel II paduan Al-Si-Mg dengan variasi persen berat Zn sebesar : 0 ; 0,5 dan 1,5 %wt, sedang Cu dibuat konstan sebesar 3 %wt.Selanjutnya dilakukan pengujian terhadap sampel-sampel tersebut, yaitu, pengujian : kekerasan, titik leleh , foto struktur mikro , SEM-EDAX dan Meping. Disamping itu juga didukung oleh data sekunder yang berupa hasil pengujian kekuatan tarik dan hasil pengujian dengan XRD.Hasil pengujian menunjukkan bahwa : semakin besar kandungan Cu , maka kekerasan akan naik, titik leleh akan turun, sedang kekuatan tariknya mula-mula naik sampai dengan kandungan Cu = 3 %wt, kemudian turun sampai kandungan Cu = 5 %wt. Disamping itu juga ditunjukkan bahwa : semakin besar kandungan Zn , maka kekerasan dan titik leleh akan turun, sedang kekuatan tariknya mula-mula turun sampai kandungan Cu = 0,5 %wt, kemudian naik sampai kandungan Cu sebesar 1,5 %wt.Hasil pengujian-pengujian tersebut menunjukkan bahwa : pada paduan tersebut muncul dua fasa yang dominan, yaitu fasa yang sangat kaya dengan Al (sebagai matrik) dan fasa yang kaya dengan Si. Disamping itu juga menunjukkan bahwa Cu dan Zn sangat mempengaruhi bentuk morfologi dari struktur mikro paduan. Morfologi struktur mikro yang fasa kaya Si-nya berbentuk serabut yang berserakan (tidak teratur) mempunyai kekuatan tarik yang relatif tinggi."

"The present study investigated the mechanical properties and microstructure of ultrafine grained (UFG) brass processed by four passes of equal channel angular pressing (ECAP) and annealed at elevated temperatures. The mechanical properties of all samples were assessed using tensile and micro-hardness tests. Microstructure analysis was performed using optical microscopy (OM) and scanning electron microscopy (SEM). Ultimate tensile strengths (UTS) and yield strengths (YS) of 878 and 804 MPa, respectively, ductility of 15%, and hardness of 248 HV were obtained for samples processed by four passes of ECAP with equivalent true strain of 4.20. Annealing at 300°C caused UTS and YS to decrease significantly, to 510 and 408 MPa, respectively, ductility to increase to 28%, and hardness to decrease to 165 HV. Fractography analysis of un-annealed samples after four ECAP passes showed small brittle fractures with shallow dimpling. Ductile failures were found on annealed samples. After four ECAP passes, the microstructure of un-annealed samples was UFG and dominated by lamellar grain with shear band. In contrast, after annealing, the microstructure changed due to recrystallization, showing nucleation and grain growth."

"This work investigates the fresh, mechanical and durability properties of normal, Self-Compacting Concrete (SCC) and Smart Dynamic Concrete (SDC), which are a new generation of concrete with a lower amount of cementitious content. SDC is a low-fine, self-compacting concrete, that combines the benefits of normal concrete (stability) and self-compacting concrete (fresh properties). Fresh properties such as slump flow, L-box and V-funnel tests were investigated to evaluate its self-compacting properties. Mechanical properties such as compressive, splitting tensile and flexural strengths were also examined to compare its effectiveness with normal concrete. In addition to the fresh and hardened properties, the rapid chloride permeability test was also conducted to check the durability of normal, SCC and SDC concrete mixtures. The test results of the fresh properties clearly showed that SDC exhibited superior flowability in the slump flow, L-box and V-funnel tests within the limits of EFNARC (The European Federation of Specialist Construction Chemical and Concrete Systems) guidelines. The mechanical properties of SDC attained higher compressive strength, splitting tensile strength and flexural strength compared with the normal and SCC concrete mixtures. The rapid chloride permeability tests result of SDC clearly showed that SDC exhibited similar and better results than that of normal and SCC concrete mixtures."

"A mechanical assembly consists of several components to perform an intended function. At the design stage, the intended function must be converted into critical product dimensions. After determining the dimensions, a designer must determine the assembly tolerance and allocate this tolerance to the tolerances of the corresponding components. After determining the optimal tolerances, process selection must be conducted along with production allocation to the selected process. There are three aspects in commercial competition that must be considered by a manufacturing company: cost, quality, and delivery. The aim of this research is to develop an optimization model for process selection for a make to order company to minimize manufacturing cost, quality loss, and lateness cost. The model attempts to determine optimal tolerance and production allocation, which takes into consideration the production capacity and process sequence. Hence, the model attempts to include not only the product design decision, but also to solve the process selection and allocation problems. A numerical example is provided to show the implementation of the model."

"In the present study, natural fibers located in thick outer woody rinds of the metroxylon sago (MS) tree were investigated. The investigation focused on measuring the mechanical properties and observing the microstructures of MS fibers before and after treatment with 5% sodium hydroxide. A scanning electron microscope was used to observe the microstructure of MS fiber, and the results showed that there was a decrease in fiber diameter after mercerization. A porous structure in the cross-section area of untreated fibers was clearly seen, and it was highly compressed after mercerization. The strength of MS fiber increased significantly after it was treated by 5% NaOH solution for two hours. The average ultimate strength of untreated MS fiber was recorded as 46 MPa; treatment with sodium hydroxide resulted in a significant increase in average ultimate strength to 163 MPa. Additionally, the elastic modulus of treated fiber was greater than that of untreated fiber."

"The definition of the physical and mechanical properties of sugarcane trash pellets were necessary for the design considerations relating to storage, handling and processing equipment. The mixing ratios of ground sugarcane trash:cassava starch:water content (1.0:0.25:0.85 and 1.0:0.25:1.40 by weight) and pelleting speeds (100, 120, 140, and 160 rpm) were considered to determine their effects on bulk density, true density, porosity, durability and compressive strength. The results show that the mixing ratio by weight of 1.0:0.25:0.85 and pelleting speed of 120 to 140 rpm were optimum for producing the sugarcane trash pellets. At the moisture content of 12.01% (wb), the bulk density, true density, durability and compressive strength of biomass pellets were in the range of 330.93 to 365.00 kg/m3, 860.38 to 918.43 kg/m3, 99.34 to 99.46 % and 5.15 to 6.43 MPa, respectively."

"The kinetics of strain aging behavior of API 5L X65 and API 5L B steel types on long-term operations were studied. Pre-strain was applied to the two steel types and the process was continued with the aging process at various temperatures and over various time periods. Mechanical properties data were used to determine activation energy levels. The results showed that API 5L B steel has a lower activation energy level than API 5L X65 steel through the identification of yield strength value, which is 13.7 kJ compared to 24.87 kJ, which means that API 5L B steel is more susceptible to strain aging than API 5L X65 steel. Predictions of long-term mechanical properties which are verified through tensile testing showed that the appropriate parameters to observe and predict the strain-aging behavior are implemented by evaluating the changes in yield strength, which gives the minimum value for the average margin of error for API 5L X65 steel and API 5L B steel, i.e. 0.3% and 0.45%, respectively. On the other hand, prediction value parameters, such as elongation, toughness and the Vickers hardness have an average margin of error range between 2.6 to 5.06%."