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Ditemukan 24695 dokumen yang sesuai dengan query
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Nirattisak Khongthon
"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."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Nirattisak Khongthon
"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."
Depok: Faculty of Engineering, Universitas Indonesia, 2016
UI-IJTECH 7:7 (2016)
Artikel Jurnal  Universitas Indonesia Library
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Pasawat Sanchumpu
"Recently, there was an
increase in demand of biomass pellets as an alternative energy source. However,
it is necessary to reduce the size of granular materials during the pelleting process.
The size reduction
of eucalyptus bark occurs in the industrial
processing of biomass pellets production, using a hammer mill
together with three sieve sizes of 3, 4, and 5 mm and the sieve speeds of 900, 1000, 1100, and 1200 rpm, respectively, which have been
examined at a feed rate of 80 kg/h. The aims of this study were to determine the
important parameters, namely rotational speed, to determine suitable sieve size
for reducing the size of eucalyptus bark, and to analyze energy usage in the
size reduction process by using a hammer mill. The results have shown that using a 5 mm sieve size at 900 rpm sieve
speed resulted in the best operating conditions in order to offer the highest
capacity and lowest specific energy consumption. Moreover, the average particle size of 0.15
mm was an acceptable value. This study could be very beneficial in the
development process to produce biomass pellets."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Azizollah Khormali
"As a result of
waterflooding, inorganic salt precipitation occurs in the different parts of an
oil production system, thereby leading to damage of production equipment.
Different parameters affect the kinetics of salt precipitation. Scale
inhibitors are widely used to prevent inorganic salt formation. In this study,
the effect of reservoir pressure, temperature, and mixing ratio of injection to
formation water on calcium sulfate and barium sulfate precipitation was
investigated. For this purpose, two different formation waters and one
injection water were used. In addition, the effect of temperature and mixing
ratio on inhibition performance was studied. Four different existing industrial
scale inhibitors and one new scale inhibitor were used. The performance of the
scale inhibitors was determined under static and dynamic conditions. Results of
the study showed that calcium sulfate precipitation increased with an increase
in temperature and a decrease in pressure. Barium sulfate precipitation was
found to increase with a decrease in the temperature. The effect of pressure on
barium sulfate formation was negligible. The developed scale inhibitor showed
the highest performance for the prevention of calcium sulfate and barium
sulfate formation. A change in temperature from 60°C to 120°C reduced the
inhibitor performance by 3%. In the cases of calcium sulfate and barium
sulfate, the minimum performance of the scale inhibitor was observed when the
mixing ratios of injection to formation waters were 60:40 and 50:50,
respectively."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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S. Abdulkareem
"This paper reports on
the investigation of thermal properties of Kapok, Coconut fibre and Sugarcane
bagasse composite materials using molasses as a binder. The composite materials were moulded into
12 cylindrical samples using Kapok, Bagasse, Coconut fibre, Kapok and Bagasse
in the ratios of (70:30; 50:50 and 30:70), Kapok and Coconut fibre in the
ratios of (70:30; 50:50 and 30:70), as well as a combination of Kapok, Bagasse
and Coconut fibre in ratios of (50:10:40; 50:40:10 and 50:30:20). The sample size is a 60 mm
diameter with 10?22 mm thickness compressed at a constant load of 180 N using a Budenberg
compression machine. Thermal conductivity and diffusivity tests were carried
out using thermocouples and the
results were read out on a Digital Multimeter MY64 (Model:
MBEB094816), while
a Digital fluke K/J thermocouple meter PRD-011 (S/NO 6835050) was used to obtain the
temperature measurement for diffusivity. It was observed that of all the twelve
samples moulded, Bagasse, Kapok plus Bagasse (50:50), Kapok plus Coconut fibre
(50:50) and Kapok plus Bagasse plus Coconut fibre (50:40:10) has the lowest
thermal conductivity of 0.0074, 0.0106, 0.0132, and 0.0127 W/(m-K) respectively
and the highest
thermal resistivity. In this regard, Bagasse has the lowest thermal
conductivity followed by Kapok plus Bagasse (50:50), Kapok plus Bagasse plus
Coconut fibre (50:40:10) and Kapok plus Coconut fibre (50:50)."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Suryadi
"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."
2017
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Nazia Hossain
"Commercialization of
bioethanol has recently intensified due to its market stability, low cost,
sustainability, alternative fuel energy composition, greener output and
colossal fossil fuel depletion. Recently, because of greenhouse intensity
worldwide, many researches are ongoing to reprocess the waste as well as
turning down the environmental pollution. With this scenario, the invention of
bioethanol was hailed as a great accomplishment to transform waste biomass to
fuel energy and in turn reduce the massive usages of fossil fuels. In this
study, our review enlightens various sources of plant-based waste feed stocks
as the raw materials for bioethanol production because they do not adversely
impact the human food chain. However, the cheapest and conventional
fermentation method, yeast fermentation is also emphasized here notably for
waste biomass-to-bioethanol conversion. Since the key fermenting agent, yeast
is readily available in local and international markets, it is more
cost-effective in comparison with other fermentation agents. Furthermore, yeast
has genuine natural fermentation capability biologically and it produces zero
chemical waste. This review also concerns a detailed overview of the biological
conversion processes of lignocellulosic waste biomass-to-bioethanol, the
diverse performance of different types of yeasts and yeast strains,
plusbioreactor design, growth kinetics of yeast fermentation, environmental
issues, integrated usages on modern engines and motor vehicles, as well as
future process development planning with some novel co-products."
2017
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Korb Srinavin
"It is widely use of
air-conditioning systems in Thailand due to its location. It is located in a
tropical zone with relatively high temperatures all year round, with high
humidity and high intensity of sunlight. In order to save electrical energy for
air-conditioning systems, preventing heat transfer into the building is
required. The objective of this study is to investigate the physical and
thermal properties of concrete blocks. An attempt is made to increase heat
resistance of concrete blocks. Foam beads (0-0.30% by weight) and kaolin (0-70% by weight) were
added in concrete block mixture to increase discontinuous voids in concrete.
Compressive strength and water absorption of concrete blocks were tested. The
testing results indicated that compressive strength decreased when foam beads
and kaolin were added. Water absorption increased when foam beads were added.
In contrast, the more kaolin added the less water absorption. The thermal
conductivity coefficient of concrete blocks was also investigated. The results
confirmed that the higher the amount of foam beads or kaolin added, the higher
the thermal resistance of concrete blocks. Thermal time-lag behavior was also
investigated. The results indicated that concrete block with kaolin took the
longest time in heating and took the shortest time in cooling. These properties
are good for heat prevention in hot climate regions. These concrete blocks
which were developed and tested in this research conform to the Thai Industrial
Standard. Finally, it can be concluded that because of its thermal behavior,
concrete block with kaolin is a suitable energy-saving concrete block for hot
and humid climates."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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"Oil palm empty fruit bunch (OPEFB) is one of the waste products of oil palm plantations and has not been optimally used in Riau Province, Sumatera, Indonesia. OPEFB is reduced by incineration, which causes pollution problems. However, the combustion of OPEFB generates ash, which is rich in potassium. Moreover, OPEFB fiber has good strength, low cost, low density, and biodegradability, and it can be used as composite reinforcement. However, the natural fibers in composites have poor compatibility with the matrix and relatively high moisture absorption. Hydrolysis of OPEFB ash creates a base solution that can be utilized in an alkaline treatment process to increase the mechanical properties of natural composites.
The aim of this study was to investigate the effect of various extracts of OPEFB ash on the tensile strength, flexural strength, and water absorption of an OPEFB fiber-polypropylene composite. The experimental design used was the Response Surface Method-Central Composite Design (RSM-CCD). The results showed that the tensile strength increased with an increase of fiber length and concentration of the OPEFB ash extract solution, but tensile strength decreased with a longer soaking time. Flexural strength increased with an increase in fiber length but decreased with an increase in the concentration of the OPEFB ash extract solution and longer soaking time. Water absorption increased with lower and higher concentrations of OPEFB ash extract solution and fiber length and with shorter and longer soaking times. The highest tensile strength (20.100 MPa) was achieved at 5%wt alkaline concentration, 36 h soaking time, and 3 cm fiber length. The highest flexural strength (30.216 MPa) was achieved at 5%wt alkaline concentration, 12 h soaking time, and 3 cm fiber length. The lowest water absorption (0.324%) was achieved at 10%wt alkaline concentration, 24 h soaking time, and 2 cm fiber length."
2016
AJ-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Ahmed Ben Mohamed
"The Aluminum 7075 (Al 7075) alloy is a precipitation hardening material instead of a strain hardening material. These mechanical properties are of a particular microstructure obtained by thermo-mechanical treatments. Among other things, this is a complicated microstructure which is responsible for the mechanical performance. The evolution of the mechanical properties of aluminum alloys is dependent on aging time parameters after heat treatment. In this study, the material has undergone a tempering heat treatment followed by a series of tensile tests. The experimental data (tensile curves in three directions during maturation time) is used to describe the evolution of the mechanical characteristics in terms of loading directions and maturation time, denoted respectively as: Ψ and t. The tensile curves are the source of data to begin the problem of identifying the behavior law of studied material using Barlat?s model and Hollomon?s isotropic hardening law. Thus, from the identified parameters (anisotropy coefficients and hardening coefficients), the evolution of the Lankford coefficient, deformation rate and load surfaces during the maturation time for three load directions (0°: rolling direction, 45° and 90°) are described. This study allows optimizing the response of the aluminum alloy to plastic strains, resulting from forming processes measured against the best time during maturation and the best load direction."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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