Abstract: In this work, the effects of scale on thermal behavior of the slab in a walking-beam type reheating furnace is studied by considering scale formation and growth in a furnace environment. Also, mathematical heat transfer model to predict the thermal radiation in a complex shaped reheating furnace with slab and skid buttons is developed with combined nongray WSGGM and blocked-off solution procedure. The model can attack the heat flux distribution within the furnace and the temperature distribution in the slab throughout the reheating furnace process by considering the heat exchange between the slab and its surroundings, including the radiant heat transfer among the slabs, the skids, the hot combustion gases and the furnace wall as well as the gas convective heat transfer in the furnace. With the introduction of the mathematical formulations validation of the present numerical model is conducted by calculating two example problems of blocked-off and nongray gas radiative heat transfer. After discussing the formation and growth of the scale on the slab surface, slab heating characteristics with scale is investigated in terms of temperature rise with time.
Abstract: The complex shape of the human pelvic bone was
successfully imaged and modeled using finite element FE processing.
The bone was subjected to quasi-static and dynamic loading
conditions simulating the effect of both weight gain and impact.
Loads varying between 500 – 2500 N (~50 – 250 Kg of weight) was
used to simulate 3D quasi-static weight gain. Two different 3D
dynamic analyses, body free fall at two different heights (1 and 2 m)
and forced side impact at two different velocities (20 and 40 Km/hr)
were also studied. The computed resulted stresses were compared for
the four loading cases, where Von Misses stresses increases linearly
with the weight gain increase under quasi-static loading. For the
dynamic models, the Von Misses stress history behaviors were
studied for the affected area and effected load with respect to time.
The normalization Von Misses stresses with respect to the applied
load were used for comparing the free fall and the forced impact load
results. It was found that under the forced impact loading condition
an over lapping behavior was noticed, where as for the free fall the
normalized Von Misses stresses behavior was found to nonlinearly
different. This phenomenon was explained through the energy
dissipation concept. This study will help designers in different
specialization in defining the weakest spots for designing different
supporting systems.
Abstract: Nowadays, financial and economic crises are growing
more and reach more countries and sectors. These events have, as a
result, a considerable impact on the activities of the firms which think
unstable and in danger.
But besides this heavy uncertainty which weighs on the different
firms, the family firm, object of our research, is not only confronted
with these external difficulties but also with an internal challenge and
of size: that of transmission. Indeed, the transmission of an
organization from one generation to another can succeed as it can
fail; leaving considerable damage.
Our research registers as part of these problems since we tried to
understand relation between the behavior of two main actors of the
process of succession, predecessor and successor; and the success of
transmission.
Abstract: Chatter vibration has been a troublesome problem
for a machine tool toward the high precision and high speed machining.
Essentially, the machining performance is determined by the dynamic
characteristics of the machine tool structure and dynamics of cutting
process, which can further be identified in terms of the stability lobe
diagram. Therefore, realization on the machine tool dynamic behavior
can help to enhance the cutting stability. To assess the dynamic
characteristics and machining stability of a vertical milling system
under the influence of a linear guide, this study developed a finite
element model integrated the modeling of linear components with the
implementation of contact stiffness at the rolling interface. Both the
finite element simulations and experimental measurements reveal that
the linear guide with different preload greatly affects the vibration
behavior and milling stability of the vertical column spindle head
system, which also clearly indicate that the predictions of the
machining stability agree well with the cutting tests. It is believed that
the proposed model can be successfully applied to evaluate the
dynamics performance of machine tool systems of various
configurations.
Abstract: Under the difficult access to finance of SMEs, they expect that its relationship with the banks shall constitute a real help to access appropriate financing, at reasonable costs and requirements, given the possibility of mutually beneficial and long lasting relation. The literature, but also the research we have carried on, is centered on such determinants as concentration and the length of the relationship, but at the same time, there is little certainty that banks are responding positively to them. Furthermore, although the trust is considered as being a fundamental element of bank relationship – see the case house bank – SMEs find that the banks finance them looking rather on collaterals and covenants than to trust. Moreover, a positive behavior, such as prompt or advance repayments of loans, doesn-t generate any positive feedback from the banks side. All these show a deep un-satisfaction of the SMEs concerning their relationship banking.
Abstract: This study examined the toxicological effects and
safety of polypeptide k isolated from the seeds of Momordica
charantia in laboratory rats. 30 male Sprague Dawley rats (12 weeks
old, bodyweight 180-200 g) were randomly divided into 3 groups
(1000 mg/kg, 500 mg and 0 mg/kg). Rats were acclimatized to
laboratory conditions for 7 days and at day 8 rats were dosed orally
with polypeptide k (in 2% DMSO/normal saline) and the controls
received the dosed vehicle only. Rats were then observed for 72
hours before sacrificed. Rats were anaesthetized by pentobarbital
(50 mg/kg ip) and 2-3.0 mL of blood was taken by cardiac puncture
and rats were scarified by anaesthetic overdose. Immediately, organs
(heart, lungs, liver, kidneys) were weigh and taken for histology.
Organ sections were then evaluated by a histopathologist. Serum
samples were assayed for liver functions (ALT and γ-GT) and kidney
functions (BUN and creatinine). All rats showed normal behavior
after the dosing and no statistical changes were observed in all blood
parameters and organ weight. Histological examinations revealed
normal organ structures. In conclusion, dosing of rats up to 1000
mg/kg did not have any effects on the rat behavior, liver or kidney
functions nor histology of the selected organs.
Abstract: Anxiety is a common disorder that attacks many people in society and often accompanied by physiological sensations such as tachycardia, chest pain, shortness of breath, insensitivity and etc. The purpose of this study is to characterize the putative anxiolytic-like effects of DEV (dichloromethane extracts of valerian) using the elevated plus maze (EPM) in rats. DEV was dissolved in DMSO and orally administered at different doses to adult male wistar rats, 0.5, 1.5 and 3 hours before behavioral evaluation in an EPM respectively. Control rats were treated with an equal volume of DMSO. Single treatment of DEV (at 0.1,0.2. 0.3, and 0.4 g/kg) significantly increased time-spent and arm entries into open arms of EPM versus control groups (p
Abstract: In This paper, the behavior of eccentric braced frame
(EBF) is studied with replacing friction damper (FD) in confluence of these braces, in 5 and 10-storey steel frames. For FD system, the main step is to determine the slip load. For this reason, the performance indexes include roof displacement, base shear, dissipated energy and relative performance should be investigated. In
nonlinear dynamic analysis, the response of structure to three
earthquake records has been obtained and the values of roof
displacement, base shear and column axial force for FD and EBF
frames have been compared. The results demonstrate that use of the FD in frames, in comparison with the EBF, substantially reduces the roof displacement, column axial force and base shear. The obtained results show suitable performance of FD in higher storey structure in
comparison with the EBF.
Abstract: The tensile properties of Mg-3%Al nanocrystalline
alloys were investigated at different test environment. Bulk
nanocrystalline samples of these alloy was successfully prepared by
mechanical alloying (MA) followed by cold compaction, sintering,
and hot extrusion process. The crystal size of the consolidated milled
sample was calculated by X-Ray line profile analysis. The
deformation mechanism and microstructural characteristic at
different test condition was discussed extensively. At room
temperature, relatively lower value of activation volume (AV) and
higher value of strain rate sensitivity (SRS) suggests that new rate
controlling mechanism accommodating plastic flow in the present
nanocrystalline sample. The deformation behavior and the
microstructural character of the present samples were discussed in
details.
Abstract: Interpolated contour maps drawn for aluminum,
copper and molybdenum in downstream monitoring boreholes of
water dam in Miduk Copper Complex and the values of pH, redox
potential (Eh) and distance from water dam indicate different trends
of variation and behavior of these three elements in downward
groundwater resources. As these maps exhibit, aluminum is dominant
in the most alkaline (pH = 9-11) borehole (MB5) to water dam. The
highest concentration of molybdenum is found in the nearest
borehole (MB6) to water dam. Main concentration of copper is
observed in the most oxidized borehole (MB3 with Eh=293.2mV).
The spatial difference among sampling stations can be attributed to
the existence of faults and diaclases in the geologic structure of
Miduk region which causes the groundwater sampling sites to be
impressed by different contamination sources (toe seepage and upper
seepage water originated from different zones of tailings dump).
Abstract: This study investigates the investors- behavioral
reaction to the investment rating change announcements from the
views of behavioral finance. The empirical results indicate that
self-interest does affect the intention of securities firms to release
investment ratings for individual stocks. In addition, behavioral
pitfalls are also found in the response of retail investors to investment
rating change announcements.
Abstract: This study attempts to validate the consumer-oriented
criteria list, developed by Wang et al. (2010), for selecting online
travel shopping sites. Based on a sample of 985 respondents,
confirmatory factor analysis was employed to test the factor structure
and assess the reliability and validity of the list. The results support the
list developed by Wang et al. (2010) and claim the list can be further
used to analyze, explain, and understand consumer behaviors about
online travel shopping.
Abstract: Server provisioning is one of the most attractive topics in virtualization systems. Virtualization is a method of running multiple independent virtual operating systems on a single physical computer. It is a way of maximizing physical resources to maximize the investment in hardware. Additionally, it can help to consolidate servers, improve hardware utilization and reduce the consumption of power and physical space in the data center. However, management of heterogeneous workloads, especially for resource utilization of the server, or so called provisioning becomes a challenge. In this paper, a new concept for managing workloads based on user behavior is presented. The experimental results show that user behaviors are different in each type of service workload and time. Understanding user behaviors may improve the efficiency of management in provisioning concept. This preliminary study may be an approach to improve management of data centers running heterogeneous workloads for provisioning in virtualization system.
Abstract: In the current decade, wireless sensor networks are
emerging as a peculiar multi-disciplinary research area. By this
way, energy efficiency is one of the fundamental research themes
in the design of Medium Access Control (MAC) protocols for
wireless sensor networks. Thus, in order to optimize the energy
consumption in these networks, a variety of MAC protocols are
available in the literature. These schemes were commonly evaluated
under simple network density and a few results are published on
their robustness in realistic network-s size. We, in this paper, provide
an analytical study aiming to highlight the energy waste sources in
wireless sensor networks. Then, we experiment three energy efficient
hybrid CSMA/CA based MAC protocols optimized for wireless
sensor networks: Sensor-MAC (SMAC), Time-out MAC (TMAC)
and Traffic aware Energy Efficient MAC (TEEM). We investigate
these protocols with different network densities in order to discuss
the end-to-end performances of these schemes (i.e. in terms of energy
efficiency, delay and throughput). Through Network Simulator (NS-
2) implementations, we explore the behaviors of these protocols with
respect to the network density. In fact, this study may help the multihops
sensor networks designers to design or select the MAC layer
which matches better their applications aims.
Abstract: Constant amplitude fatigue crack growth (FCG) tests
were performed on dissimilar metal welded plates of Type 316L
Stainless Steel (SS) and IS 2062 Grade A Carbon steel (CS). The
plates were welded by TIG welding using SS E309 as electrode. FCG
tests were carried on the Side Edge Notch Tension (SENT)
specimens of 5 mm thickness, with crack initiator (notch) at base
metal region (BM), weld metal region (WM) and heat affected zones
(HAZ). The tests were performed at a test frequency of 10 Hz and at
load ratios (R) of 0.1 & 0.6. FCG rate was found to increase with
stress ratio for weld metals and base metals, where as in case of
HAZ, FCG rates were almost equal at high ΔK. FCG rate of HAZ of
stainless steel was found to be lowest at low and high ΔK. At
intermediate ΔK, WM showed the lowest FCG rate. CS showed
higher crack growth rate at all ΔK. However, the scatter band of data
was found to be narrow. Fracture toughness (Kc) was found to vary
in different locations of weldments. Kc was found lowest for the
weldment and highest for HAZ of stainless steel. A novel method of
characterizing the FCG behavior using an Infrared thermography
(IRT) camera was attempted. By monitoring the temperature rise at
the fast moving crack tip region, the amount of plastic deformation
was estimated.
Abstract: Use of microemulsion in enhanced oil recovery has become more attractive in recent years because of its high level of extraction efficiency. Experimental investigations have been made on characterization of microemulsions of oil-brinesurfactant/ cosurfactant system for its use in enhanced oil recovery (EOR). Sodium dodecyl sulfate, propan-1-ol and heptane were selected as surfactant, cosurfactant and oil respectively for preparation of microemulsion. The effects of salinity on the relative phase volumes and solubilization parameters have also been studied. As salinity changes from low to high value, phase transition takes place from Winsor I to Winsor II via Winsor III. Suitable microemulsion composition has been selected based on its stability and ability to reduce interfacial tension. A series of flooding experiments have been performed using the selected microemulsion. The flooding experiments were performed in a core flooding apparatus using uniform sand pack. The core holder was tightly packed with uniform sands (60-100 mesh) and saturated with brines of different salinities. It was flooded with the brine at 25 psig and the absolute permeability was calculated from the flow rate of the through sand pack. The sand pack was then flooded with the crude oil at 800 psig to irreducible water saturation. The initial water saturation was determined on the basis of mass balance. Waterflooding was conducted by placing the coreholder horizontally at a constant injection pressure at 200 pisg. After water flooding, when water-cut reached above 95%, around 0.5 pore volume (PV) of the above microemulsion slug was injected followed by chasing water. The experiments were repeated using different composition of microemulsion slug. The additional recoveries were calculated by material balance. Encouraging results with additional recovery more than 20% of original oil in place above the conventional water flooding have been observed.
Abstract: High level synthesis (HLS) is a process which
generates register-transfer level design for digital systems from
behavioral description. There are many HLS algorithms and
commercial tools. However, most of these algorithms consider a
behavioral description for the system when a single token is
presented to the system. This approach does not exploit extra
hardware efficiently, especially in the design of digital filters where
common operations may exist between successive tokens. In this
paper, we modify the behavioral description to process multiple
tokens in parallel. However, this approach is unlike the full
processing that requires full hardware replication. It exploits the
presence of common operations between successive tokens. The
performance of the proposed approach is better than sequential
processing and approaches that of full parallel processing as the
hardware resources are increased.
Abstract: Website plays a significant role in success of an e-business. It is the main start point of any organization and corporation for its customers, so it's important to customize and design it according to the visitors' preferences. Also, websites are a place to introduce services of an organization and highlight new service to the visitors and audiences. In this paper, we will use web usage mining techniques, as a new field of research in data mining and knowledge discovery, in an Iranian government website. Using the results, a framework for web content layour is proposed. An agent is designed to dynamically update and improve web links locations and layout. Then, we will explain how it is used to directly enable top managers of the organization to influence on the arrangement of web contents and also to enhance customization of web site navigation due to online users' behaviors.
Abstract: When considering the development of constitutive
equations describing the behavior of materials under cyclic plastic
strains, different kinds of formulations can be adopted. The primary
intention of this study is to develop computer programming of
plasticity models to accurately predict the life of engineering
components. For this purpose, the energy or cyclic strain is computed
in multi-surface plasticity models in non-proportional loading and to
present their procedures and codes results.
Abstract: The influence of lactulose and inulin on rheological
properties of fermented milk during storage was studied.Pasteurized
milk, freeze-dried starter culture Bb-12 (Bifidobacterium lactis, Chr.
Hansen, Denmark), inulin – RAFTILINE®HP (ORAFI, Belgium) and
syrup of lactulose (Duphalac®, the Netherlands) were used for
experiments. The fermentation process was realized at 37 oC for 16
hours and the storage of products was provided at 4 oC for 7 days.
Measurements were carried out by BROOKFIELD standard methods
and the flow curves were described by Herschel-Bulkley model.
The results of dispersion analysis have shown that both the
concentration of prebiotics (p=0.04