Abstract: In this paper, the effects of the restoring force device on the response of a space frame structure resting on sliding type of bearing with a restoring force device is studied. The NS component of the El - Centro earthquake and harmonic ground acceleration is considered for earthquake excitation. The structure is modeled by considering six-degrees of freedom (three translations and three rotations) at each node. The sliding support is modeled as a fictitious spring with two horizontal degrees of freedom. The response quantities considered for the study are the top floor acceleration, base shear, bending moment and base displacement. It is concluded from the study that the displacement of the structure reduces by the use of the restoring force device. Also, the peak values of acceleration, bending moment and base shear also decreases. The simulation results show the effectiveness of the developed and proposed method.
Abstract: Ground-source heat pumps achieve higher efficiencies
than conventional air-source heat pumps because they exchange heat
with the ground that is cooler in summer and hotter in winter than the
air environment. Earth heat exchangers are essential parts of the
ground-source heat pumps and the accurate prediction of their
performance is of fundamental importance. This paper presents the
development and validation of a numerical model through an
incompressible fluid flow, for the simulation of energy and
temperature changes in and around a U-tube borehole heat
exchanger. The FlexPDE software is used to solve the resulting
simultaneous equations that model the heat exchanger. The validated
model (through a comparison with experimental data) is then used to
extract conclusions on how various parameters like the U-tube
diameter, the variation of the ground thermal conductivity and
specific heat and the borehole filling material affect the temperature
of the fluid.
Abstract: Semisolid metal processing uses solid–liquid slurries
containing fine and globular solid particles uniformly distributed in a
liquid matrix, which can be handled as a solid and flow like a liquid.
In the recent years, many methods have been introduced for the
production of semisolid slurries since it is scientifically sound and
industrially viable with such preferred microstructures called
thixotropic microstructures as feedstock materials. One such process
that needs very low equipment investment and running costs is the
cooling slope. In this research by using a mechanical stirrer slurry
maker constructed by the authors, the effects of mechanical stirring
parameters such as: stirring time, stirring temperature and stirring
Speed on micro-structure and mechanical properties of A360
aluminum alloy in semi-solid forming, are investigated. It is
determined that mold temperature and holding time of part in
temperature of 580ºC have a great effect on micro-structure and
mechanical properties(stirring temperature of 585ºC, stirring time of
20 minutes and stirring speed of 425 RPM). By optimizing the
forming parameters, dendrite microstructure changes to globular and
mechanical properties improves. This is because of breaking and
globularzing dendrites of primary α-AL.
Abstract: This paper analyzed the perception of e-commerce
application services by construction material traders in Malaysia.
Five attributes were tested: usability, reputation, trust, privacy and
familiarity. Study methodology consists of survey questionnaire and
statistical analysis that includes reliability analysis, factor analysis,
ANOVA and regression analysis. The respondents were construction
material traders, including hardware stores in Klang Valley, Kuala
Lumpur.
Findings support that usability and familiarity with e-commerce
services in Malaysia have insignificant influence on the acceptance of
e-commerce application. However, reputation, trust and privacy
attributes have significant influence on the choice of e-commerce
acceptance by construction material traders. E-commerce
applications studied included customer database, e-selling, emarketing,
e-payment, e-buying and online advertising. Assumptions
are made that traders have basic knowledge and exposure to ICT
services. i.e. internet service and computers. Study concludes that
reputation, privacy and trust are the three website attributes that
influence the acceptance of e-commerce by construction material
traders.
Abstract: Monitoring the tool flank wear without affecting the
throughput is considered as the prudent method in production
technology. The examination has to be done without affecting the
machining process. In this paper we proposed a novel work that is
used to determine tool flank wear by observing the sound signals
emitted during the turning process. The work-piece material we used
here is steel and aluminum and the cutting insert was carbide
material. Two different cutting speeds were used in this work. The
feed rate and the cutting depth were constant whereas the flank wear
was a variable. The emitted sound signal of a fresh tool (0 mm flank
wear) a slightly worn tool (0.2 -0.25 mm flank wear) and a severely
worn tool (0.4mm and above flank wear) during turning process were
recorded separately using a high sensitive microphone. Analysis
using Singular Value Decomposition was done on these sound
signals to extract the feature sound components. Observation of the
results showed that an increase in tool flank wear correlates with an
increase in the values of SVD features produced out of the sound
signals for both the materials. Hence it can be concluded that wear
monitoring of tool flank during turning process using SVD features
with the Fuzzy C means classification on the emitted sound signal is
a potential and relatively simple method.
Abstract: The objective of the research was to evaluate the
quality of milk pomade sweet – sherbet packed in different packaging
materials (Multibarrier 60, met.BOPET/PE, Aluthen), by several
packaging technologies – active and modified atmosphere (MAP)
(consisting of 100% CO2), and control – in air ambiance.
Experiments were carried out at the Faculty of Food Technology of
Latvia University of Agriculture. Samples were stored at the room
temperature +21±1 °C. The physiochemical properties – weight
losses, moisture, hardening, colour and changes in headspace
atmosphere concentration (CO2 and O2) of packs were analysed
before packaging and after 2, 4, 6, 8, 10 and 12 storage weeks.
Abstract: Abrasive waterjet is a novel machining process capable of processing wide range of hard-to-machine materials. This research addresses modeling and optimization of the process parameters for this machining technique. To model the process a set of experimental data has been used to evaluate the effects of various parameter settings in cutting 6063-T6 aluminum alloy. The process variables considered here include nozzle diameter, jet traverse rate, jet pressure and abrasive flow rate. Depth of cut, as one of the most important output characteristics, has been evaluated based on different parameter settings. The Taguchi method and regression modeling are used in order to establish the relationships between input and output parameters. The adequacy of the model is evaluated using analysis of variance (ANOVA) technique. The pairwise effects of process parameters settings on process response outputs are also shown graphically. The proposed model is then embedded into a Simulated Annealing algorithm to optimize the process parameters. The optimization is carried out for any desired values of depth of cut. The objective is to determine proper levels of process parameters in order to obtain a certain level of depth of cut. Computational results demonstrate that the proposed solution procedure is quite effective in solving such multi-variable problems.
Abstract: Meat and meat products for human consumption are one of main sources of protein, amino acids, fatty acids, vitamins, and minerals. Popular variety of meat product is meatballs, which can be enriched with valuable product – Jerusalem artichoke powder, made from dried and grinded Jerusalem artichoke tubers, it is raw material with low-calorie, low fat, rich in dietary fibres, minerals, and vitamins. The results of this study indicate that that people could accept the new product - meatballs with Jerusalem artichoke powder and Jerusalem artichoke powder is suitable for meatballs preparation, in result them is possible to improve meatballs sensory and physical properties.
Abstract: terrorism and extremism are among the most
dangerous and difficult to forecast the phenomena of our time, which
are becoming more diverse forms and rampant. Terrorist attacks often
produce mass casualties, involve the destruction of material and
spiritual values, beyond the recovery times, sow hatred among
nations, provoke war, mistrust and hatred between the social and
national groups, which sometimes can not be overcome within a
generation. Currently, the countries of Central Asia are a topical issue
– the threat of terrorism and religious extremism, which grow not
only in our area, but throughout the world. Of course, in each of the
terrorist threat is assessed differently. In our country the problem of
terrorism should not be acutely. Thus, after independence and
sovereignty of Kazakhstan has chosen the path of democracy,
progress and free economy. With the policy of the President of
Kazakhstan Nursultan Nazarbayev and well-organized political and
economic reforms, there has been economic growth and rising living
standards, socio-political stability, ensured civil peace and accord in
society [1].
Abstract: Swedish truck industry is investigating the possibility
for implementing the use of Compacted Graphite Iron (CGI) in their
heavy duty diesel engines. Compared to the alloyed gray iron used
today, CGI has superior mechanical properties but not as good
machinability. Another issue that needs to be addressed when
implementing CGI is the inhomogeneous microstructure when the
cast component has different section thicknesses, as in cylinder
blocks. Thinner sections results in finer pearlite, in the material, with
higher strength. Therefore an investigation on its influence on
machinability was needed. This paper focuses on the effect that
interlamellar distance in pearlite has on CGI machinability and
material physical properties. The effect of pearlite content and
nodularity is also examined. The results showed that interlamellar
distance in pearlite did not have as large effect on the material
physical properties or machinability as pearlite content. The paper
also shows the difficulties of obtaining a homogeneous
microstructure in inhomogeneous workpieces.
Abstract: The storage of thermal energy as a latent heat of phase
change material (PCM) has created considerable interest among
researchers in recent times. Here, an attempt is made to carry out
numerical investigations to analyze the performance of latent heat
storage units (LHSU) employing phase change material. The
mathematical model developed is based on an enthalpy formulation.
Freezing time of PCM packed in three different shaped containers
viz. rectangular, cylindrical and cylindrical shell is compared. The
model is validated with the results available in the literature. Results
show that for the same mass of PCM and surface area of heat
transfer, cylindrical shell container takes the least time for freezing
the PCM and this geometric effect is more pronounced with an
increase in the thickness of the shell than that of length of the shell.
Abstract: High voltage generators are being subject to higher
voltage rating and are being designed to operate in harsh conditions.
Stator windings are the main component of generators in which
Electrical, magnetical and thermal stresses remain major failures for
insulation degradation accelerated aging. A large number of
generators failed due to stator winding problems, mainly insulation
deterioration. Insulation degradation assessment plays vital role in the
asset life management. Mostly the stator failure is catastrophic
causing significant damage to the plant. Other than generation loss,
stator failure involves heavy repair or replacement cost. Electro
thermal analysis is the main characteristic for improvement design of
stator slot-s insulation. Dielectric parameters such as insulation
thickness, spacing, material types, geometry of winding and slot are
major design consideration. A very powerful method available to
analyze electro thermal performance is Finite Element Method
(FEM) which is used in this paper. The analysis of various stator coil
and slot configurations are used to design the better dielectric system
to reduce electrical and thermal stresses in order to increase the
power of generator in the same volume of core. This paper describes
the process used to perform classical design and improvement
analysis of stator slot-s insulation.
Abstract: In this study, it is investigated the stability boundary of
Functionally Graded (FG) panel under the heats and supersonic
airflows. Material properties are assumed to be temperature
dependent, and a simple power law distribution is taken. First-order
shear deformation theory (FSDT) of plate is applied to model the
panel, and the von-Karman strain- displacement relations are
adopted to consider the geometric nonlinearity due to large
deformation. Further, the first-order piston theory is used to model the
supersonic aerodynamic load acting on a panel and Rayleigh damping
coefficient is used to present the structural damping. In order to find a
critical value of the speed, linear flutter analysis of FG panels is
performed. Numerical results are compared with the previous works,
and present results for the temperature dependent material are
discussed in detail for stability boundary of the panel with various
volume fractions, and aerodynamic pressures.
Abstract: In this study, we sought to investigate the mercury
removal efficiency of manganese oxides from natural gas. The
fundamental studies on mercury removal with manganese oxides
sorbents were carried out in a laboratory scale fixed bed reactor at 30
°C with a mixture of methane (20%) and nitrogen gas laden with 4.8
ppb of elemental mercury. Manganese oxides with varying surface
area and crystalline phase were prepared by conventional precipitation
method in this study. The effects of surface area, crystallinity and
other metal oxides on mercury removal efficiency were investigated.
Effect of Ag impregnation on mercury removal efficiency was also
investigated. Ag supported on metal oxide such titania and zirconia as
reference materials were also used in this study for comparison. The
characteristics of mercury removal reaction with manganese oxide
was investigated using a temperature programmed desorption (TPD)
technique.
Manganese oxides showed very high Hg removal activity (about
73-93% Hg removal) for first time use. Surface area of the manganese
oxide samples decreased after heat-treatment and resulted in complete
loss of Hg removal ability for repeated use after Hg desorption in the
case of amorphous MnO2, and 75% loss of the initial Hg removal
activity for the crystalline MnO2. Mercury desorption efficiency of
crystalline MnO2 was very low (37%) for first time use and high (98%)
after second time use. Residual potassium content in MnO2 may have
some effect on the thermal stability of the adsorbed Hg species.
Desorption of Hg from manganese oxides occurs at much higher
temperatures (with a peak at 400 °C) than Ag/TiO2 or Ag/ZrO2.
Mercury may be captured on manganese oxides in the form of mercury
manganese oxide.
Abstract: Waste problem is becoming a future problem all over the world. Magnesium wastes which can be used in recycling processes are produced by many industrial activities. Magnesium borates which have useful properties such as; high heat resistance, corrosion resistance, supermechanical strength, superinsulation, light weight, high coefficient of elasticity and so on. Addition, magnesium borates have great potential in the development of ceramic and detergents industry, whisker-reinforced composites, antiwear, and reducing friction additives.
In this study, using the starting materials of waste magnesium and H3BO3 the hydrothermal method was applied at a moderate temperature of 70oC with different reaction times. Several reaction times of waste magnesium to H3BO3 were selected as; 30, 60, 120, 240 minutes. After the synthesis, X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FT-IR) techniques were applied to products. As a result, the forms of Admontite [MgO(B2O3)3.7(H2O)] and Mcallisterite [Mg2(B6O7(OH)6)2.9(H2O)] were synthesized.
Abstract: The heat storage capacity of concrete in building shells is a major reason for excessively large electricity consumption induced by indoor air conditioning. In this research, the previously developed Smart Temperature Information Material (STIM) is embedded in two groups of exterior wall specimens (the control group contains reinforced concrete exterior walls and the experimental group consists of tiled exterior walls). Long term temperature measurements within the concrete are taken by the embedded STIM. Temperature differences between the control group and the experimental group in walls facing the four cardinal directions (east, west, south, and north) are evaluated. This study aims to provide a basic reference for the design of exterior walls and the selection of heat insulation materials.
Abstract: In the last decade, carbohydrates have attracted great
attention as renewable resources for the chemical industry.
Carbohydrates are abundantly found in nature in the form of
monomers, oligomers and polymers, or as components of
biopolymers and other naturally occurring substances. As natural
products, they play important roles in conferring certain physical,
chemical, and biological properties to their carrier molecules.The
synthesis of this particular carbohydrate glycomonomer is part of our
work to obtain biodegradable polymers. Our current paper describes
the synthesis and characterization of a novel carbohydrate
glycomonomer starting from D-glucose, in several synthesis steps,
that involve the protection/deprotection of the D-glucose ring via
acetylation, tritylation, then selective deprotection of the aromaticaliphatic
protective group, in order to obtain 1,2,3,4-tetra-O-acetyl-
6-O-allyl-β-D-glucopyranose. The glycomonomer was then obtained
by the allylation in drastic conditions of 1,2,3,4-tetra-O-acetyl-6-Oallyl-
β-D-glucopyranose with allylic alcohol in the presence of
stannic chloride, in methylene chloride, at room temperature. The
proposed structure of the glycomonomer, 2,3,4-tri-O-acetyl-1,6-di-
O-allyl-β-D-glucopyranose, was confirmed by FTIR, NMR and
HPLC-MS spectrometry. This glycomonomer will be further
submitted to copolymerization with certain acrylic or methacrylic
monomers in order to obtain competitive plastic materials for
applications in the biomedical field.
Abstract: This study deals with a multi-criteria optimization
problem which has been transformed into a single objective
optimization problem using Response Surface Methodology (RSM),
Artificial Neural Network (ANN) and Grey Relational Analyses
(GRA) approach. Grey-RSM and Grey-ANN are hybrid techniques
which can be used for solving multi-criteria optimization problem.
There have been two main purposes of this research as follows.
1. To determine optimum and robust fiber dyeing process
conditions by using RSM and ANN based on GRA,
2. To obtain the best suitable model by comparing models
developed by different methodologies.
The design variables for fiber dyeing process in textile are
temperature, time, softener, anti-static, material quantity, pH,
retarder, and dispergator. The quality characteristics to be evaluated
are nominal color consistency of fiber, maximum strength of fiber,
minimum color of dyeing solution. GRA-RSM with exact level
value, GRA-RSM with interval level value and GRA-ANN models
were compared based on GRA output value and MSE (Mean Square
Error) performance measurement of outputs with each other. As a
result, GRA-ANN with interval value model seems to be suitable
reducing the variation of dyeing process for GRA output value of the
model.
Abstract: Charging and discharging phenomenon on the surface
of materials can be found in plasma display panel, spacecraft
charging, high voltage insulator, etc. This report gives a simple
explanation on this phenomenon. A scanning electron microscope
was used not only as a tool to produce energetic electron beam to
charge an insulator without metallic coating and to produce a surface
discharging (surface breakdown/flashover) but also to observe the
visible charging and discharging on the sample surface. A model of
electric field distribution on the surface was developed in order to
explain charging and discharging phenomena. Since charging and
discharging process involves incubation time, therefore this process
can be used to evaluate the insulation property of materials under
electron bombardment.
Abstract: The tubes in an Ammonia primary reformer furnace
operate close to the limits of materials technology in terms of the
stress induced as a result of very high temperatures, combined with
large differential pressures across the tube wall. Operation at tube
wall temperatures significantly above design can result in a rapid
increase in the number of tube failures, since tube life is very
sensitive to the absolute operating temperature of the tube. Clearly it
is important to measure tube wall temperatures accurately in order to
prevent premature tube failure by overheating.. In the present study,
the catalyst tubes in an Ammonia primary reformer has been modeled
taking into consideration heat, mass and momentum transfer as well
as reformer characteristics.. The investigations concern the effects of
tube characteristics and superficial tube wall temperatures on of the
percentage of heat flux, unconverted methane and production of
Hydrogen for various values of steam to carbon ratios. The results
show the impact of catalyst tubes length and diameters on the
performance of operating parameters in ammonia primary reformers.