Abstract: Subdivision surfaces were applied to the entire
meshes in order to produce smooth surfaces refinement from coarse
mesh. Several schemes had been introduced in this area to provide a
set of rules to converge smooth surfaces. However, to compute and
render all the vertices are really inconvenient in terms of memory
consumption and runtime during the subdivision process. It will lead
to a heavy computational load especially at a higher level of
subdivision. Adaptive subdivision is a method that subdivides only at
certain areas of the meshes while the rest were maintained less
polygons. Although adaptive subdivision occurs at the selected areas,
the quality of produced surfaces which is their smoothness can be
preserved similar as well as regular subdivision. Nevertheless,
adaptive subdivision process burdened from two causes; calculations
need to be done to define areas that are required to be subdivided and
to remove cracks created from the subdivision depth difference
between the selected and unselected areas. Unfortunately, the result
of adaptive subdivision when it reaches to the higher level of
subdivision, it still brings the problem with memory consumption.
This research brings to iterative process of adaptive subdivision to
improve the previous adaptive method that will reduce memory
consumption applied on triangular mesh. The result of this iterative
process was acceptable better in memory and appearance in order to
produce fewer polygons while it preserves smooth surfaces.
Abstract: Cavitation, usually known as a destructive
phenomenon, involves turbulent unsteady two-phase flow. Having
such features, cavitating flows have been turned to a challenging
topic in numerical studies and many researches are being done for
better understanding of bubbly flows and proposing solutions to
reduce its consequent destructive effects. Aeration may be regarded
as an effective protection against cavitation erosion in many
hydraulic structures, like gated tunnels. The paper concerns
numerical simulation of flow in discharge gated tunnel of a dam
using ing RNG k -ε model coupled with the volume of fluid (VOF)
method and the zone which is susceptible of cavitation inception in
the tunnel is predicted. In the second step, a vent is considered in the
mentioned zone for aeration and the numerical simulation is done
again to study the effects of aeration. The results show that aeration
is an impressively useful method to exclude cavitation in mentioned
tunnels.
Abstract: This paper investigates the effect of replacing
crankshaft with cam on the indicated torque during compression and
power strokes in internal combustion engines. A Cycloidal cam
profile was used in Revetec engine to calculate and compare the
torque to a conventional engine, using a computational method.
Firstly, the cylinder pressure was calculated using Ferguson equation,
and then the torque calculated depending on cylinder pressure values
in every crank angle. the results showed that by using Cycloidal cam
profile in Revetec engine the torque can increased by 14% compared
with conventional engines, which means an increase in engine
efficiency.
Abstract: Stormwater wetlands have been mainly designed in an
empirical approach for water quality improvement, with little
quantitative understanding of the internal microbial processes. This
study investigated into heterotrophic bacterial production rate,
heterotrophic bacterial mineralization percentage, and algal biomass
in hypertrophic and eutrophic surface flow stormwater wetlands.
Compared to a nearby wood leachate treatment wetland, the
stormwater wetlands had much higher chlorophyll-a concentrations.
The eutrophic stormwater wetland had improved water quality,
whereas the hypertrophic stormwater wetland had degraded water
quality. Heterotrophic bacterial activities in water were limited in the
stormwater wetlands due to competition of algal growth for nutrients.
The relative contribution of biofilms to the overall heterotrophic
activities was higher in the stormwater wetlands than that in the wood
leachate treatment wetland.
Abstract: This work discusses an innovative methodology for
deployment of service quality characteristics. Four groups of organizational features that may influence the quality of services are identified: human resource, technology, planning, and organizational
relationships. A House of Service Quality (HOSQ) matrix is built to
extract the desired improvement in the service quality characteristics
and to translate them into a hierarchy of important organizational
features. The Mean Square Error (MSE) criterion enables the
pinpointing of the few essential service quality characteristics to be
improved as well as selection of the vital organizational features. The
method was implemented in an engineering supply enterprise and
provides useful information on its vital service dimensions.
Abstract: Narratives are invaluable assets of human lives. Due to
the distinct features of narratives, they are useful for supporting human
reasoning processes. However, many useful narratives become
residuals in organizations or human minds nowadays. Researchers
have contributed effort to investigate and improve narrative generation
processes. This paper attempts to contemplate essential components in
narratives and explore a computational approach to acquire and extract
knowledge to generate narratives. The methodology and significant
benefit for decision support are presented.
Abstract: The quality of a machined surface is becoming more and more important to justify the increasing demands of sophisticated component performance, longevity, and reliability. Usually, any machining operation leaves its own characteristic evidence on the machined surface in the form of finely spaced micro irregularities (surface roughness) left by the associated indeterministic characteristics of the different elements of the system: tool-machineworkpart- cutting parameters. However, one of the most influential sources in machining affecting surface roughness is the instantaneous state of tool edge. The main objective of the current work is to relate the in-process immeasurable cutting edge deformation and surface roughness to a more reliable easy-to-measure force signals using a robust non-linear time-dependent modeling regression techniques. Time-dependent modeling is beneficial when modern machining systems, such as adaptive control techniques are considered, where the state of the machined surface and the health of the cutting edge are monitored, assessed and controlled online using realtime information provided by the variability encountered in the measured force signals. Correlation between wear propagation and roughness variation is developed throughout the different edge lifetimes. The surface roughness is further evaluated in the light of the variation in both the static and the dynamic force signals. Consistent correlation is found between surface roughness variation and tool wear progress within its initial and constant regions. At the first few seconds of cutting, expected and well known trend of the effect of the cutting parameters is observed. Surface roughness is positively influenced by the level of the feed rate and negatively by the cutting speed. As cutting continues, roughness is affected, to different extents, by the rather localized wear modes either on the tool nose or on its flank areas. Moreover, it seems that roughness varies as wear attitude transfers from one mode to another and, in general, it is shown that it is improved as wear increases but with possible corresponding workpart dimensional inaccuracy. The dynamic force signals are found reasonably sensitive to simulate either the progressive or the random modes of tool edge deformation. While the frictional force components, feeding and radial, are found informative regarding progressive wear modes, the vertical (power) components is found more representative carrier to system instability resulting from the edge-s random deformation.
Abstract: Statistical selection procedures are used to select the
best simulated system from a finite set of alternatives. In this paper,
we present a procedure that can be used to select the best system
when the number of alternatives is large. The proposed procedure
consists a combination between Ranking and Selection, and Ordinal
Optimization procedures. In order to improve the performance of Ordinal
Optimization, Optimal Computing Budget Allocation technique
is used to determine the best simulation lengths for all simulation
systems and to reduce the total computation time. We also argue
the effect of increment in simulation samples for the combined
procedure. The results of numerical illustration show clearly the effect
of increment in simulation samples on the proposed combination of
selection procedure.
Abstract: Adhesion strength of exterior or interior coating of
steel pipes is too important. Increasing of coating adhesion on
surfaces can increase the life time of coating, safety factor of
transmitting line pipe and decreasing the rate of corrosion and costs.
Preparation of steel pipe surfaces before doing the coating process is
done by shot and grit blasting. This is a mechanical way to do it.
Some effective parameters on that process, are particle size of
abrasives, distance to surface, rate of abrasive flow, abrasive physical
properties, shapes, selection of abrasive, kind of machine and its
power, standard of surface cleanness degree, roughness, time of
blasting and weather humidity. This search intended to find some
better conditions which improve the surface preparation, adhesion
strength and corrosion resistance of coating. So, this paper has
studied the effect of varying abrasive flow rate, changing the
abrasive particle size, time of surface blasting on steel surface
roughness and over blasting on it by using the centrifugal blasting
machine. After preparation of numbers of steel samples (according to
API 5L X52) and applying epoxy powder coating on them, to
compare strength adhesion of coating by Pull-Off test. The results
have shown that, increasing the abrasive particles size and flow rate,
can increase the steel surface roughness and coating adhesion
strength but increasing the blasting time can do surface over blasting
and increasing surface temperature and hardness too, change,
decreasing steel surface roughness and coating adhesion strength.
Abstract: Guard channels improve the probability of successful
handoffs by reserving a number of channels exclusively for handoffs.
This concept has the risk of underutilization of radio spectrum due to
the fact that fewer channels are granted to originating calls even if
these guard channels are not always used, when originating calls are
starving for the want of channels. The penalty is the reduction of
total carried traffic. The optimum number of guard channels can help
reduce this problem. This paper presents fuzzy logic based guard
channel scheme wherein guard channels are reorganized on the basis
of traffic density, so that guard channels are provided on need basis.
This will help in incorporating more originating calls and hence high
throughput of the radio spectrum
Abstract: This paper presents the utilizing of ferroelectric
material on antenna application. There are two different ferroelectric
had been used on the proposed antennas which include of Barium
Strontium Titanate (BST) and Bismuth Titanate (BiT), suitable for
Access Points operating in the WLAN IEEE 802.11 b/g and WiMAX
IEEE 802.16 within the range of 2.3 GHz to 2.5 GHz application.
BST, which had been tested to own a dielectric constant of εr = 15
while BiT has a dielectric constant that higher than BST which is εr =
21 and both materials are in rectangular shaped. The influence of
various parameters on antenna characteristics were investigated
extensively using commercial electromagnetic simulations software
by Communication Simulation Technology (CST). From theoretical
analysis and simulation results, it was demonstrated that ferroelectric
material used have not only improved the directive emission but also
enhanced the radiation efficiency.
Abstract: A high performance thin layer chromatography
system (HPTLC) for the separation of vitamin B2 and B12 has been
developed. The separation was successfully using a solvent system of
methanol, water, ammonia 7.3.1 (V/V) as mobile phase on HPTLC
plates impregnated with boric acid. The effect of other mobile phases
on the separation of vitamins was also examined. The method is
based on different behavior of investigated compounds in
impregnated TLC plates with different amount of boric acid. The Rf
values of vitamin B2 and B12 are considered on non impregnated
and impregnated silica gel HPTLC plate with boric acid. The effect
of boric acid in the mobile phase and on HPTLC plates on the RF
values of the vitamins has also been studied.
Abstract: The appearance management behavior of tanning by gay men is examined through the lens of Impression Formation. The study proposes that body image, self-esteem, and internalized homophobia are connected and affect the motives for engaging in sun, salon, and cosmetic tanning. Motives examined were: to look masculine, to look attractive to (potential) partners, to look attractive in general, to socialize, to meet a peer standard, and for personal satisfaction. Using regression analysis to examine data of 103 gay men who engage in at least one method of tanning, results reveal that components of body image and internalized homophobia–but not self-esteem–are linked to various motives and methods of tanning. These findings support and extend the literature of Impression Formation Theory and provide practitioners in the health and healthrelated fields new avenues to pursue when dealing with diseases related to tanning.
Abstract: In designing river intakes and diversion structures, it is paramount that the sediments entering the intake are minimized or, if possible, completely separated. Due to high water velocity, sediments can significantly damage hydraulic structures especially when mechanical equipment like pumps and turbines are used. This subsequently results in wasting water, electricity and further costs. Therefore, it is prudent to investigate and analyze the performance of lateral intakes affected by sediment control structures. Laboratory experiments, despite their vast potential and benefits, can face certain limitations and challenges. Some of these include: limitations in equipment and facilities, space constraints, equipment errors including lack of adequate precision or mal-operation, and finally, human error. Research has shown that in order to achieve the ultimate goal of intake structure design – which is to design longlasting and proficient structures – the best combination of sediment control structures (such as sill and submerged vanes) along with parameters that increase their performance (such as diversion angle and location) should be determined. Cost, difficulty of execution and environmental impacts should also be included in evaluating the optimal design. This solution can then be applied to similar problems in the future. Subsequently, the model used to arrive at the optimal design requires high level of accuracy and precision in order to avoid improper design and execution of projects. Process of creating and executing the design should be as comprehensive and applicable as possible. Therefore, it is important that influential parameters and vital criteria is fully understood and applied at all stages of choosing the optimal design. In this article, influential parameters on optimal performance of the intake, advantages and disadvantages, and efficiency of a given design are studied. Then, a multi-criterion decision matrix is utilized to choose the optimal model that can be used to determine the proper parameters in constructing the intake.
Abstract: Object: Review recent publications of patient safety
culture to investigate the relationship between leadership behavior,
safety culture, and safety performance in the healthcare industry.
Method: This study is a cross-sectional study, 350 questionnaires were
mailed to hospital workers with 195 valid responses obtained, and a
55.7% valid response rate. Confirmatory factor analysis (CFA) was
carried out to test the factor structure and determine if the composite
reliability was significant with a factor loading of >0.5, resulting in an
acceptable model fit. Results: Through the analysis of One-way
ANOVA, the results showed that physicians significantly have more
negative patient safety culture perceptions and safety performance
perceptions than non- physicians. Conclusions: The path analysis
results show that leadership behavior affects safety culture and safety
performance in the health care industry. Safety performance was
affected and improved with contingency leadership and a positive
patient safety organization culture. The study suggests improving
safety performance by providing a well-managed system that
includes: consideration of leadership, hospital worker training
courses, and a solid safety reporting system.
Abstract: Ion-acoustic solitary waves in a plasma with
nonthermal electrons, thermal positrons and warm ions are
investigated using Sagdeev-s pseudopotential technique. We study
the effects of non-thermal electrons and ion temperature on solitons
and show both negative and positive potential waves are possible.
Abstract: Global competitiveness has recently become the
biggest concern of both manufacturing and service companies.
Electronic commerce, as a key technology enables the firms to reach
all the potential consumers from all over the world. In this study, we
have presented commonly used electronic payment systems, and then
we have shown the evaluation of these systems in respect to different
criteria. The payment systems which are included in this research are
the credit card, the virtual credit card, the electronic money, the
mobile payment, the credit transfer and the debit instruments. We
have realized a systematic comparison of these systems in respect to
three main criteria: Technical, economical and social. We have
conducted a fuzzy multi-criteria decision making procedure to deal
with the multi-attribute nature of the problem. The subjectiveness
and imprecision of the evaluation process are modeled using
triangular fuzzy numbers.
Abstract: This paper presents an improved variable ordering method to obtain the minimum number of nodes in Reduced Ordered Binary Decision Diagrams (ROBDD). The proposed method uses the graph topology to find the best variable ordering. Therefore the input Boolean function is converted to a unidirectional graph. Three levels of graph parameters are used to increase the probability of having a good variable ordering. The initial level uses the total number of nodes (NN) in all the paths, the total number of paths (NP) and the maximum number of nodes among all paths (MNNAP). The second and third levels use two extra parameters: The shortest path among two variables (SP) and the sum of shortest path from one variable to all the other variables (SSP). A permutation of the graph parameters is performed at each level for each variable order and the number of nodes is recorded. Experimental results are promising; the proposed method is found to be more effective in finding the variable ordering for the majority of benchmark circuits.
Abstract: Stress analysis of functionally graded composite plates
composed of ceramic, functionally graded material and metal layers is
investigated using 3-D finite element method. In FGM layer, material
properties are assumed to be varied continuously in the thickness
direction according to a simple power law distribution in terms of the
volume fraction of a ceramic and metal. The 3-D finite element model
is adopted by using an 18-node solid element to analyze more
accurately the variation of material properties in the thickness
direction. Numerical results are compared for three types of materials.
In the analysis, the tensile and the compressive stresses are
summarized for various FGM thickness ratios, volume fraction
distributions, geometric parameters and mechanical loads.
Abstract: Block replacement algorithms to increase hit ratio
have been extensively used in cache memory management. Among
basic replacement schemes, LRU and FIFO have been shown to be
effective replacement algorithms in terms of hit rates. In this paper,
we introduce a flexible stack-based circuit which can be employed in
hardware implementation of both LRU and FIFO policies. We
propose a simple and efficient architecture such that stack-based
replacement algorithms can be implemented without the drawbacks
of the traditional architectures. The stack is modular and hence, a set
of stack rows can be cascaded depending on the number of blocks in
each cache set. Our circuit can be implemented in conjunction with
the cache controller and static/dynamic memories to form a cache
system. Experimental results exhibit that our proposed circuit
provides an average value of 26% improvement in storage bits and its
maximum operating frequency is increased by a factor of two