Abstract: The present study is concerned with effect of exciting
boundary layer on increase in heat transfer from flat surfaces. As any
increase in heat transfer between a fluid inside a face and another one
outside of it can cause an increase in some equipment's efficiency, so
at this present we have tried to increase the wall's heat transfer
coefficient by exciting the fluid boundary layer. By a collision
between flow and the placed block at the fluid way, the flow pattern
and the boundary layer stability will change. The flow way inside the
channel is simulated as a 2&3-dimensional channel by Gambit
TM
software.
With studying the achieved results by this simulation for the flow
way inside the channel with a block coordinating with Fluent
TM
software, it's determined that the figure and dimensions of the exciter
are too important for exciting the boundary layer so that any increase
in block dimensions in vertical side against the flow and any
reduction in its dimensions at the flow side can increase the average
heat transfer coefficient from flat surface and increase the flow
pressure loss. Using 2&3-dimensional analysis on exciting the flow at
the flow way inside a channel by cylindrical block at the same time
with the external flow, we came to this conclusion that the heat flux
transferred from the surface, is increased considerably in terms of the
condition without excitation. Also, the k-e turbulence model is used.
Abstract: Following the research in the Department of environmental engineering in Faculty of mechanical engineering on Technical University of Kosice and experiences with electrocoagulation style of disposal waste water, there were designed and partly examining the equipment of two stage revitalization on the standing and little fusible water of tenet electrolysis on the little tarns. With the cooperation with vet experts was that manners prove and it is innocuous for animals, during which time cyanobacteria are totally paralyzed. For the implementation of science and research results have been obtained by means EU funds for structural development.
Abstract: Optimizing equipment selection in heavy earthwork
operations is a critical key in the success of any construction project.
The objective of this research incentive was geared towards
developing a computer model to assist contractors and construction
managers in estimating the cost of heavy earthwork operations.
Economical operation analysis was conducted for an equipment fleet
taking into consideration the owning and operating costs involved in
earthwork operations. The model is being developed in a Microsoft
environment and is capable of being integrated with other estimating
and optimization models. In this study, Caterpillar® Performance
Handbook [5] was the main resource used to obtain specifications of
selected equipment. The implementation of the model shall give
optimum selection of equipment fleet not only based on cost
effectiveness but also in terms of versatility. To validate the model, a
case study of an actual dam construction project was selected to
quantify its degree of accuracy.
Abstract: Rotational Smart Lighting Control System can supply
the quantity of lighting which is required to run plants by rotating few
LED and Fluorescent instead of that are used in the existing plant
factories.The initial installation of the existing plants factory is
expensive, so in order to solve the problem with smart lighting control
system was developed.
The beam required intensity for the growth of crops, Photosynthetic
Photon Flux Density(PPFD)is calculated; and the number of LED, are
installed on the blades, set; using the Lighting Simulation
Program.Relux, it is able to confirm that the difference of the beam
intensity between the center and the outer of lighting system when the
lighting device is rotating.
Abstract: Development of intelligent assembly cell conception includes new solution kind of how to create structures of automated and flexible assembly system. The current trend of the final product quality increasing is affected by time analysis of the entire manufacturing process. The primary requirement of manufacturing is to produce as many products as soon as possible, at the lowest possible cost, but of course with the highest quality. Such requirements may be satisfied only if all the elements entering and affecting the production cycle are in a fully functional condition. These elements consist of sensory equipment and intelligent control elements that are essential for building intelligent manufacturing systems. Intelligent behavior of the system as the control system will repose on monitoring of important parameters of the system in the real time. Intelligent manufacturing system itself should be a system that can flexibly respond to changes in entering and exiting the process in interaction with the surroundings.
Abstract: At present, the tendency to implement the conditionbased
maintenance (CBM), which allows the optimization of the
expenses for equipment monitoring, is more and more evident; also,
the transformer substations with remote monitoring are increasingly
used. This paper reviews all the advantages of the on-line monitoring
and presents an equipment for on-line monitoring of bushings, which
is the own contribution of specialists who are the authors of this
paper. The paper presents a study of the temperature field, using the
finite element method. For carrying out this study, the 3D modelling
of the above mentioned bushing was performed. The analysis study is
done taking into account the extreme thermal stresses, focusing at the
level of the first cooling wing section of the ceramic insulator. This
fact enables to justify the tanδ variation in time, depending on the
transformer loading and the environmental conditions. With a view
to reducing the variation of dielectric losses in bushing insulation, the
use of ferrofuids instead of mineral oils is proposed.
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: This paper provides some thoughts about the lack of
attentiveness of building commissioning in the construction industry
and the lack of handling in project commissioning as an integral part
of the project life-cycle. Many have perceived commissioning as the
problem solving process of a project, rather than the start up of the
equipment, or the handing over of the project to the client. Therefore,
there is a lack of proper attention in the planning of commissioning
as a vital part of the project life-cycle. This review paper aims to
highlight the benefits of building commissioning and to propose the
lacking of knowledge gap on building commissioning. Finally, this
paper hopes to propose the shift of focus on this matter in future
research.
Abstract: This paper presents a compact thermoelectric power generator system based on temperature difference across the element. The system can transfer the burning heat energy to electric energy directly. The proposed system has a thermoelectric generator and a power control box. In the generator, there are 4 thermoelectric modules (TEMs), each of which uses 2 thermoelectric chips (TEs) and 2 cold sinks, 1 thermal absorber, and 1 thermal conduction flat board. In the power control box, there are 1 storing energy device, 1 converter, and 1 inverter. The total net generating power is about 11W. This system uses commercial portable gas stoves or burns timber or the coal as the heat source, which is easily obtained. It adopts solid-state thermoelectric chips as heat inverter parts. The system has the advantages of being light-weight, quite, and mobile, requiring no maintenance, and havng easily-supplied heat source. The system can be used a as long as burning is allowed. This system works well for highly-mobilized outdoors situations by providing a power for illumination, entertainment equipment or the wireless equipment at refuge. Under heavy storms such as typhoon, when the solar panels become ineffective and the wind-powered machines malfunction, the thermoelectric power generator can continue providing the vital power.
Abstract: Conventionally the selection of parameters depends
intensely on the operator-s experience or conservative technological
data provided by the EDM equipment manufacturers that assign
inconsistent machining performance. The parameter settings given by
the manufacturers are only relevant with common steel grades. A
single parameter change influences the process in a complex way.
Hence, the present research proposes artificial neural network (ANN)
models for the prediction of surface roughness on first commenced
Ti-15-3 alloy in electrical discharge machining (EDM) process. The
proposed models use peak current, pulse on time, pulse off time and
servo voltage as input parameters. Multilayer perceptron (MLP) with
three hidden layer feedforward networks are applied. An assessment
is carried out with the models of distinct hidden layer. Training of the
models is performed with data from an extensive series of
experiments utilizing copper electrode as positive polarity. The
predictions based on the above developed models have been verified
with another set of experiments and are found to be in good
agreement with the experimental results. Beside this they can be
exercised as precious tools for the process planning for EDM.
Abstract: Bendability is constrained by maximum top roller
load imparting capacity of the machine. Maximum load is
encountered during the edge pre-bending stage of roller bending.
Capacity of 3-roller plate bending machine is specified by
maximum thickness and minimum shell diameter combinations that
can be pre-bend for given plate material of maximum width.
Commercially available plate width or width of the plate that can be
accommodated on machine decides the maximum rolling width.
Original equipment manufacturers (OEM) provide the machine
capacity chart based on reference material considering perfectly
plastic material model. Reported work shows the bendability analysis
of heavy duty 3-roller plate bending machine. The input variables for
the industry are plate thickness, shell diameter and material property
parameters, as it is fixed by the design. Analytical models of
equivalent thickness, equivalent width and maximum width based on
power law material model were derived to study the bendability.
Equation of maximum width provides bendability for designed
configuration i.e. material property, shell diameter and thickness
combinations within the machine limitations. Equivalent thicknesses
based on perfectly plastic and power law material model were
compared for four different materials grades of C-Mn steel in order
to predict the bend-ability. Effect of top roller offset on the
bendability at maximum top roller load imparting capacity is
reported.
Abstract: Modeling transfer phenomena in several chemical
engineering operations leads to the resolution of partial differential
equations systems. According to the complexity of the operations
mechanisms, the equations present a nonlinear form and analytical
solution became difficult, we have then to use numerical methods
which are based on approximations in order to transform a
differential system to an algebraic one.Finite element method is one
of numerical methods which can be used to obtain an accurate
solution in many complex cases of chemical engineering.The packed
columns find a large application like contactor for liquid-liquid
systems such solvent extraction. In the literature, the modeling of this
type of equipment received less attention in comparison with the
plate columns.A mathematical bidimensionnal model with radial and
axial dispersion, simulating packed tower extraction behavior was
developed and a partial differential equation was solved using the
finite element method by adopting the Galerkine model. We
developed a Mathcad program, which can be used for a similar
equations and concentration profiles are obtained along the column.
The influence of radial dispersion was prooved and it can-t be
neglected, the results were compared with experimental concentration
at the top of the column in the extraction system:
acetone/toluene/water.
Abstract: This study aims at investigating factors in research
and development (R&D) growth and exploring the role of R&D
management in enhancing social innovation and productivity
improvement in Iran-s industrial sector. It basically explores the
common types of R&D activities and the industries which benefited
the most from active R&D units in Iran. The researchers generated
qualitative analyses obtained from primary and secondary data.
The primary data have been retrieved through interviews with five
key players (Managing Director, Internal Manager, General Manager,
Executive Manager, and Project Manager) in the industrial sector.
The secondary data acquired from an investigation on Mazandaran, a
province of northern Iran. The findings highlight Iran-s focuses of R
& D on cost reduction and upgrading productivity. Industries that
have benefited the most from active R&D units are metallic,
machinery and equipment design, and automotive.
We rank order the primary effects of R&D on productivity
improvement as follows, industry improvement, economic growth,
using professional human resources, generating productivity and
creativity culture, creating a competitive and innovative environment,
and increasing people-s knowledge.
Generally, low budget dedication and insufficient supply of highly
skilled scientists and engineers are two important obstacles for R&D
in Iran. Whereas, R&D has resulted in improvement in Iranian
society, transfer of contemporary knowledge into the international
market is still lacking.
Abstract: A laboratory set-up was designed to survey the
effectiveness of UV/O3 advanced oxidation process (AOP) for the
removal of Carbaryl from polluted water in batch reactor. The study
was carried out by UV/O3 process for water samples containing 1 to
20 mg/L of Carbaryl in distilled water. Also the range of drinking
water resources adjusted in synthetic water and effects of contact
time, pH and Carbaryl concentration were studied. The residual
pesticide concentration was determined by applying high
performance liquid chromatography (HPLC). The results indicated
that increasing of retention time and pH, enhances pesticide removal
efficiency. The removal efficiency has been affected by pesticide
initial concentration. Samples with low pesticide concentration
showed a remarkable removal efficiency compared to the samples
with high pesticide concentration. AOP method showed the removal
efficiencies of 80% to 100%. Although process showed high
performance for removal of pesticide from water samples, this
process has different disadvantages including complication,
intolerability, difficulty of maintenance and equipmental and
structural requirements.
Abstract: Degradation of polymeric insulation systems of
electrical equipments increases the space charge density and the
concentration of electrical dipoles. By consequence, the maximum
values and the slopes of absorption/resorption (A/R) currents can
change with insulation systems ageing. In this paper, an analysis of
the nature of the A/R currents and the importance of their
components, especially the polarization current and the current given
by the space charge, is presented. The experimental study concerns
the A/R currents measurements of plane samples (made from
CALMICAGLAS tapes), virgin and thermally accelerated aged. The
obtained results show that the ageing process produces an increase of
the values and a decrease of shapes of the A/R currents. Finally, the
possibility of estimating insulations ageing state and lifetime from
A/R currents measurements is discussed.
Abstract: This work aims to test the application of computational fluid dynamics (CFD) modeling to fixed bed catalytic cracking reactors. Studies of CFD with a fixed bed design commonly use a regular packing with N=2 to define bed geometry. CFD allows us to obtain a more accurate view of the fluid flow and heat transfer mechanisms present in fixed bed equipment. Naphtha was used as feedstock and the reactor length was 80cm. It is divided in three sections that catalyst bed packed in the middle section of the reactor. The reaction scheme was involved one primary reaction and 24 secondary reactions. Because of high CPU times in these simulations, parallel processing have been used. In this study the coke formation process in fixed bed and empty tube reactor was simulated and coke in these reactors are compared. In addition, the effect of steam ratio and feed flow rate on coke formation was investigated.
Abstract: Increasing demand on the performance of Subsea
Production Systems (SPS) suggests a need for more detailed
investigation of fluid behavior taking place in subsea equipment.
Complete CFD cool down analyses of subsea equipment are very
time demanding. The objective of this paper is to investigate a
Locked CFD approach, which enables significant reduction of the
computational time and at the same time maintains sufficient
accuracy during thermal cool down simulations. The result
comparison of a dead leg simulation using the Full CFD and the three
LCFD-methods confirms the validity of the locked flow field
assumption for the selected case. For the tested case the LCFD
simulation speed up by factor of 200 results in the absolute thermal
error of 0.5 °C (3% relative error), speed up by factor of 10 keeps the
LCFD results within 0.1 °C (0.5 % relative error) comparing to the
Full CFD.
Abstract: The major objective of this study is to understand the
potential of a newly fabricated equipment to study the thermal
properties of nonwoven textile fabrics treated with aerogel at subzero
temperatures. Thermal conductivity was calculated by using the
empirical relation Fourier’s law, The relationship between the
thermal conductivity and thermal resistance of the samples were
studied at various environmental temperatures (which was set in the
clima temperature system between +25oC to -25oC). The newly
fabricated equipment was found to be a suitable for measuring at
subzero temperatures. This field of measurements is being developed
and will be the subject of further research which will be more suitable
for measurement of the various thermal characteristics.
Abstract: Effective cooling of electronic equipment has emerged
as a challenging and constraining problem of the new century. In the
present work the feasibility and effectiveness of jet impingement
cooling on electronics were investigated numerically and
experimentally. Studies have been conducted to see the effect of the
geometrical parameters such as jet diameter (D), jet to target
spacing (Z) and ratio of jet spacing to jet diameter (Z/D) on the heat
transfer characteristics. The values of Reynolds numbers considered
are in the range 7000 to 42000. The results obtained from the
numerical studies are validated by conducting experiments. From the
studies it is found that the optimum value of Z/D ratio is 5. For a
given Reynolds number, the Nusselt number increases by about 28%
if the diameter of the nozzle is increased from 1mm to 2mm.
Correlations are proposed for Nusselt number in terms of Reynolds
number and these are valid for air as the cooling medium.
Abstract: This study was conducted to investigate the incidence
of pathogenic bacteria: Salmonella, Shigella, Escherichia coli O157
and Staphylococcus aureus in cakes and tarts collected from thirtyfive
confectionery producing and selling premises located within
Tripoli city, Libya. The results revealed an incidence of S. aureus
with 94.4 and 48.0 %, E. coli O157 with 14.7 and 4.0 % and Salmonella
sp. with 5.9 and 8.0 % in cakes and tarts samples respectively;
while Shigella was not detected in all samples. In order to determine
the source of these pathogenic bacteria, cotton swabs were taken
from the hands of workers on the production line, the surfaces of
preparation tables and cream whipping instruments. The results
showed that the cotton swabs obtained from the hands of workers
contained S. aureus and Salmonella sp. with an incidence of 42.9 and
2.9 %, the cotton swabs obtained from the surfaces of preparation
tables 22.9 and 2.9 % and the cotton swabs obtained from the cream
whipping instruments 14.3 and 0.0 % respectively; while E. coli
O157 and Shigella sp. were not detected in all swabs. Additionally,
other bacteria were isolated from the hands of workers and the Surfaces
of producing equipments included: Aeromonas sp., Pseudomonas
sp., E. coli, Klebsiella sp., Enterobacter sp., Citrobacter sp.,
Proteus sp., Serratia sp. and Acinetobacter sp. These results indicate
that some of the cakes and tarts might pose threat to consumer's
health. Meanwhile, occurrences of pathogenic bacteria on the hands
of those who are working in production line and the surfaces of
equipments reflect poor hygienic practices at most confectionery
premises examined in this study. Thus, firm and continuous surveillance
of these premises is needed to insure the consumer's health and
safety.