Abstract: Evaporator is an important and widely used heat
exchanger in air conditioning and refrigeration industries. Different
methods have been used by investigators to increase the heat transfer
rates in evaporators. One of the passive techniques to enhance heat
transfer coefficient is the application of microfin tubes. The
mechanism of heat transfer augmentation in microfin tubes is
dependent on the flow regime of two-phase flow. Therefore many
investigations of the flow patterns for in-tube evaporation have been
reported in literatures. The gravitational force, surface tension and
the vapor-liquid interfacial shear stress are known as three dominant
factors controlling the vapor and liquid distribution inside the tube. A
review of the existing literature reveals that the previous
investigations were concerned with the two-phase flow pattern for
flow boiling in horizontal tubes [12], [9]. Therefore, the objective of
the present investigation is to obtain information about the two-phase
flow patterns for evaporation of R-134a inside horizontal smooth and
microfin tubes. Also Investigation of heat transfer during flow
boiling of R-134a inside horizontal microfin and smooth tube have
been carried out experimentally The heat transfer coefficients for
annular flow in the smooth tube is shown to agree well with Gungor
and Winterton-s correlation [4]. All the flow patterns occurred in the
test can be divided into three dominant regimes, i.e., stratified-wavy
flow, wavy-annular flow and annular flow. Experimental data are
plotted in two kinds of flow maps, i.e., Weber number for the vapor
versus weber number for the liquid flow map and mass flux versus
vapor quality flow map. The transition from wavy-annular flow to
annular or stratified-wavy flow is identified in the flow maps.
Abstract: Currently, one of the main directions is developing of
development based on the clustering of economic operations of
Kazakhstan, providing for the organization and concentration of
production capacity in one region or the most optimal system. In the
modern economic literature clustering is regarded as one of the most
effective tools to ensure competitive businesses, and improve their
business itself.
Abstract: Quality costs are the costs associated with preventing,
finding, and correcting defective work. Since the main language of
corporate management is money, quality-related costs act as means of
communication between the staff of quality engineering departments
and the company managers. The objective of quality engineering is to
minimize the total quality cost across the life of product. Quality
costs provide a benchmark against which improvement can be
measured over time. It provides a rupee-based report on quality
improvement efforts. It is an effective tool to identify, prioritize and
select quality improvement projects. After reviewing through the
literature it was noticed that a simplified methodology for data
collection of quality cost in a manufacturing industry was required.
The quantified standard methodology is proposed for collecting data
of various elements of quality cost categories for manufacturing
industry. Also in the light of research carried out so far, it is felt
necessary to standardise cost elements in each of the prevention,
appraisal, internal failure and external failure costs. . Here an attempt
is made to standardise the various cost elements applicable to
manufacturing industry and data is collected by using the proposed
quantified methodology. This paper discusses the case study carried
in luggage manufacturing industry.
Abstract: Functional imaging procedures for the non-invasive assessment of tissue microcirculation are highly requested, but require a mathematical approach describing the trans- and intercapillary passage of tracer particles. Up to now, two theoretical, for the moment different concepts have been established for tracer kinetic modeling of contrast agent transport in tissues: pharmacokinetic compartment models, which are usually written as coupled differential equations, and the indicator dilution theory, which can be generalized in accordance with the theory of lineartime- invariant (LTI) systems by using a convolution approach. Based on mathematical considerations, it can be shown that also in the case of an open two-compartment model well-known from functional imaging, the concentration-time course in tissue is given by a convolution, which allows a separation of the arterial input function from a system function being the impulse response function, summarizing the available information on tissue microcirculation. Due to this reason, it is possible to integrate the open two-compartment model into the system-theoretic concept of indicator dilution theory (IDT) and thus results known from IDT remain valid for the compartment approach. According to the long number of applications of compartmental analysis, even for a more general context similar solutions of the so-called forward problem can already be found in the extensively available appropriate literature of the seventies and early eighties. Nevertheless, to this day, within the field of biomedical imaging – not from the mathematical point of view – there seems to be a trench between both approaches, which the author would like to get over by exemplary analysis of the well-known model.
Abstract: This paper proposes a meta-heuristic called Ant Colony Optimization to solve multi-objective production problems. The multi-objective function is to minimize lead time and work in process. The problem is related to the decision variables, i.e.; distance and process time. According to decision criteria, the mathematical model is formulated. In order to solve the model an ant colony optimization approach has been developed. The proposed algorithm is parameterized by the number of ant colonies and the number of pheromone trails. One example is given to illustrate the effectiveness of the proposed model. The proposed formulations; Max-Min Ant system are then used to solve the problem and the results evaluate the performance and efficiency of the proposed algorithm using simulation.
Abstract: The global chaos synchronization for a class of time-delayed power systems is investigated via observer-based approach. By employing the concepts of quadratic stability theory and generalized system model, a new sufficient criterion for constructing an observer is deduced. In contrast to the previous works, this paper proposes a theoretical and systematic design procedure to realize chaos synchronization for master-slave power systems. Finally, an illustrative example is given to show the applicability of the obtained scheme.
Abstract: Inconel718 has been widely used as a super alloy in aerospace application due to the high strength at elevated temperatures, satisfactory oxidation resistance and heat corrosion resistance. In this study, the Inconel718 has been fabricated using high technology of Metal Injection Molding (MIM) process due to the cost effective technique for producing small, complex and precision parts in high volume compared with conventional method through machining. Through MIM, the binder system is one of the most important criteria in order to successfully fabricate the Inconel718. Even though, the binder system is a temporary, but failure in the selection and removal of the binder system will affect on the final properties of the sintered parts. Therefore, the binder system based on palm oil derivative which is palm stearin has been formulated and developed to replace the conventional binder system. The rheological studies of the mixture between the powder and binders system have been determined properly in order to be successful during injection into injection molding machine. After molding, the binder holds the particles in place. The binder system has to be removed completely through debinding step. During debinding step, solvent debinding and thermal pyrolysis has been used to remove completely of the binder system. The debound part is then sintered to give the required physical and mechanical properties. The results show that the properties of the final sintered parts fulfill the Standard Metal Powder Industries Federation (MPIF) 35 for MIM parts.
Abstract: An adaptive software reliability prediction model
using evolutionary connectionist approach based on Recurrent Radial
Basis Function architecture is proposed. Based on the currently
available software failure time data, Fuzzy Min-Max algorithm is
used to globally optimize the number of the k Gaussian nodes. The
corresponding optimized neural network architecture is iteratively
and dynamically reconfigured in real-time as new actual failure time
data arrives. The performance of our proposed approach has been
tested using sixteen real-time software failure data. Numerical results
show that our proposed approach is robust across different software
projects, and has a better performance with respect to next-steppredictability
compared to existing neural network model for failure
time prediction.
Abstract: Software maintenance and mainly software
comprehension pose the largest costs in the software lifecycle. In
order to assess the cost of software comprehension, various
complexity measures have been proposed in the literature. This paper
proposes new cognitive-spatial complexity measures, which combine
the impact of spatial as well as architectural aspect of the software to
compute the software complexity. The spatial aspect of the software
complexity is taken into account using the lexical distances (in
number of lines of code) between different program elements and the
architectural aspect of the software complexity is taken into
consideration using the cognitive weights of control structures
present in control flow of the program. The proposed measures are
evaluated using standard axiomatic frameworks and then, the
proposed measures are compared with the corresponding existing
cognitive complexity measures as well as the spatial complexity
measures for object-oriented software. This study establishes that the
proposed measures are better indicators of the cognitive effort
required for software comprehension than the other existing
complexity measures for object-oriented software.
Abstract: Sleep stage scoring is the process of classifying the
stage of the sleep in which the subject is in. Sleep is classified into
two states based on the constellation of physiological parameters.
The two states are the non-rapid eye movement (NREM) and the
rapid eye movement (REM). The NREM sleep is also classified into
four stages (1-4). These states and the state wakefulness are
distinguished from each other based on the brain activity. In this
work, a classification method for automated sleep stage scoring
based on a single EEG recording using wavelet packet decomposition
was implemented. Thirty two ploysomnographic recording from the
MIT-BIH database were used for training and validation of the
proposed method. A single EEG recording was extracted and
smoothed using Savitzky-Golay filter. Wavelet packets
decomposition up to the fourth level based on 20th order Daubechies
filter was used to extract features from the EEG signal. A features
vector of 54 features was formed. It was reduced to a size of 25 using
the gain ratio method and fed into a classifier of regression trees. The
regression trees were trained using 67% of the records available. The
records for training were selected based on cross validation of the
records. The remaining of the records was used for testing the
classifier. The overall correct rate of the proposed method was found
to be around 75%, which is acceptable compared to the techniques in
the literature.
Abstract: An alternative iterative computational procedure is
proposed for internal normal ball loads calculation in statically
loaded single-row, angular-contact ball bearings, subjected to a
known thrust load, which is applied in the inner ring at the geometric
bearing center line. An accurate method for curvature radii at
contacts with inner and outer raceways in the direction of the motion
is used. Numerical aspects of the iterative procedure are discussed.
Numerical examples results for a 218 angular-contact ball bearing
have been compared with those from the literature. Twenty figures
are presented showing the geometrical features, the behavior of the
convergence variables and the following parameters as functions of
the thrust load: normal ball loads, contact angle, distance between
curvature centers, and normal ball and axial deflections.
Abstract: This experiment was conducted to investigate the
effect of dietary supplementation of different levels of black seed
(Nigella sativa L.) on the performance and immune response of broiler chicks. A total 240 day-old broiler chicks were used and
randomly allotted equally into six experimental groups designated as 1, 2, 3, 4, 5 and 6 having black seed at the rate of 0, 2, 4, 6, 8 and
10 g /kg diet respectively. The study was lasted for 42 days. Average body weight, weight gain, relative growth rate, feed
conversion, antibody titer against Newcastle disease, phagocytic activity and phagocytic index, some blood parameters(GOT, GPT,
Glucose, Cholesterol, Triglyceride, Total protein, Albumen, WBCs,
RBCs, Hb and PCV), dressing percentage, weight of different body
organs, abdominal fat weight, were determined. It was found that, N. Sativa significantly improved final body weight, total body gain
and feed conversion ratio of groups 2 and 3 when compared with the control group. Higher levels of N. Sativa did not improve
growth performance of the chicks. Non significant differences were
observed for antibody titer against Newcastle virus, WBCs count,
serum GOT, glucose level, dressing %, relative liver, spleen, heart and head percentages. Lymphoid organs (Bursa and Thymus)
improved significantly with increasing N. Sativa level in all supplemented groups. Serum cholesterol, triglyceride and visible fat
% significantly decreased with Nigella sativa supplementation while
serum GPT level significantly increased with nigella sativa
supplementation.
Abstract: Peer review is an activity where students review their
classmates- writing and then evaluate the content, development, unity
and organization. Studies have shown that peer review activities
benefit both the reviewer and the writer in developing their reading
and writing skills. Furthermore, peer review activities may also
enhance students- soft skills. This study was conducted to find out the
benefits of peer review activity in a technical writing class based on
engineering students- perceptions. The study also highlights how
these benefits could improve the students- soft skills. A set of
questionnaire was given to 200 undergraduate students of a technical
writing course. The results of the study indicate that the activity could
help improve their critical thinking skills, written and oral
communication skills, as well as team work. This paper further
discusses how the implications of these benefits could help enhance
students- soft skills.
Abstract: Nowadays, Multimedia Communication has been developed and improved rapidly in order to enable users to communicate between each other over the Internet. In general, the multimedia communication consists of audio and video communication. However, this paper focuses on audio streams. The audio translation between protocols is a very critical issue due to solving the communication problems between any two protocols, as well as it enables people around the world to talk with each other at anywhere and anytime even they use different protocols. In this paper, a proposed method for an audio translation module between two protocols has been presented. These two protocols are InterAsterisk eXchange Protocol (IAX) and Real Time Switching Control Protocol (RSW), which they are widely used to provide two ways audio transfer feature. The result of this work is to introduce possibility of interworking together.
Abstract: A method is presented for using thermo-mechanical fatigue analysis as a tool in the design of automotive heat exchangers. Use of infra-red thermography to measure the real thermal history in the heat exchanger reduces the time necessary for calculating design parameters and improves prediction accuracy. Thermal shocks are the primary cause of heat exchanger damage. Thermo-mechanical simulation is based on the mean behavior of the aluminum tubes used in the heat exchanger. An energetic fatigue criterion is used to detect critical zones.
Abstract: In this paper, optimal generation expansion planning (GEP) is investigated considering purchase prices, profits of independent power producers (IPPs) and reliability criteria using a new method based on hybrid coded Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). In this approach, optimal purchase price of each IPP is obtained by HCGA and reliability criteria are calculated by PSO technique. It should be noted that reliability criteria and the rate of carbon dioxide (CO2) emission have been considered as constraints of the GEP problem. Finally, the proposed method has been tested on the case study system. The results evaluation show that the proposed method can simply obtain optimal purchase prices of IPPs and is a fast method for calculation of reliability criteria in expansion planning. Also, considering the optimal purchase prices and profits of IPPs in generation expansion planning are caused that the expansion costs are decreased and the problem is solved more exactly.
Abstract: Robustness is one of the primary performance criteria for an Intelligent Video Surveillance (IVS) system. One of the key factors in enhancing the robustness of dynamic video analysis is,providing accurate and reliable means for shadow detection. If left undetected, shadow pixels may result in incorrect object tracking and classification, as it tends to distort localization and measurement information. Most of the algorithms proposed in literature are computationally expensive; some to the extent of equalling computational requirement of motion detection. In this paper, the homogeneity property of shadows is explored in a novel way for shadow detection. An adaptive division image (which highlights homogeneity property of shadows) analysis followed by a relatively simpler projection histogram analysis for penumbra suppression is the key novelty in our approach.
Abstract: The modern queueing theory is one of the powerful
tools for a quantitative and qualitative analysis of communication systems, computer networks, transportation systems, and many other technical systems. The paper is designated to the analysis of queueing
systems, arising in the networks theory and communications theory
(called open queueing network). The authors of this research in the
sphere of queueing theory present the theorem about the law of the iterated logarithm (LIL) for the queue length of a customers in open
queueing network and its application to the mathematical model of
the open message switching system.
Abstract: Walking as a type of non-motorized transportation has
various social, economical and environmental privileges. Also, today
different aspects of sustainable development have been emphasized
and promotion of sustainable transportation modes has been
considered according to this approach. Therefore, the objective of
this research is exploring the circumstance of relationship between
walking and sustainable urban transportation.For writing this article,
the most important resources related to the traits of walking have
been surveyed via a documentary method and after explaining the
concept of sustainable transportation and its indicators, benefiting
from the viewpoints of transportation experts of Tehran, as the capital
and greatest city of Iran, different modes of urban transportation have
been compared in proportion to each criterion and to each other and
have been analyzed according to AHP method. The results of this
study indicate that walking is the most sustainable mode of inner city
transportation.
Abstract: Indigenous Knowledge (IK) has many social and
economic benefits. However, IK is at the risk of extinction due to the
difficulties to preserve it as most of the IK largely remains
undocumented. This study aims to design a model of the factors
affecting the adoption of Information and Communication
Technologies (ICTs) for the preservation of IK. The proposed model
is based on theoretical frameworks on ICT adoption. It was designed
following a literature review of ICT adoption theories for households,
and of the factors affecting ICT adoption for IK. The theory that
fitted to the best all factors was then chosen as the basis for the
proposed model. This study found that the Model of Adoption of
Technology in Households (MATH) is the most suitable theoretical
framework for modeling ICT adoption factors for the preservation of
IK.