Abstract: In this study, we investigated numerically heat
transfer by mixed convection coupled to radiation in a square cavity;
the upper horizontal wall is movable. The purpose of this study is to
see the influence of the emissivity ε and the varying of the
Richardson number Ri on the variation of average Nusselt number
Nu. The vertical walls of the cavity are differentially heated, the left
wall is maintained at a uniform temperature higher than the right
wall, and the two horizontal walls are adiabatic. The finite volume
method is used for solving the dimensionless Governing Equations.
Emissivity values used in this study are ranged between 0 and 1, the
Richardson number in the range 0.1 to 10. The Rayleigh number is
fixed to Ra=104 and the Prandtl number is maintained constant
Pr=0.71. Streamlines, isothermal lines and the average Nusselt
number are presented according to the surface emissivity. The results
of this study show that the Richardson number Ri and emissivity ε
affect the average Nusselt number.
Abstract: In present study, a large deposit of oolitic iron ore of
Late Carboniferous-Permotriassic-Lower Jurassic age was discovered
in Wadi Halfa and Argein areas, North Sudan. It seems that the iron
ore mineralization exists in the west and east bank of the River Nile
of the study area that are found on the Egyptian-Sudanese border.
The Carboniferous-Lower Jurassic age strata were covered by 67
sections and each section has been examined and carefully described.
The iron-ore in Wadi Halfa occurs as oolitic ironstone and contained
two horizons: (A) horizon and (B) horizon. Only horizon (A) was
observed in southern Argein area. The texture of the ore is variable
depending on the volume of the component. In thin sections, the
average of the ooids was ranged between 90%-80%. The matrix
varies between 10%-20% by volume and detritus quartz in other
component my reach up to 30% by volume in sandy massive ore.
Ooids size ranges from 0.2mm-1.00 mm on average in very coarse
ooids may attend up to 1 mm in size. The matrix around the ooids is
dominated by iron hydroxide, carbonate, fine, and amorphous silica.
The probable ore reserve estimate of 1.234 billion at a head grade of
41.29% Fe for the Wadi Halfa Oolitic Ironstone Formation. The iron
ore shows higher content of phosphorus ranges from 6.15% to 0.16%,
with mean 1.45%. The new technology Hatch–Ironstone Chloride
Segregation (HICS) can be used to produce commercial-quality of
iron and reduce phosphorus and silica to acceptable levels for steel
industry. The presence of infrastructures in addition to the presence
of massive quantities of iron ore would make exploitation
economically.
Abstract: Pure nickel coatings have been successfully
electrodeposited on copper substrates by the pulse plating technique.
The influence of current density, duty cycle and pulse frequency on
the surface morphology, crystal orientation, and microhardness was
determined. It was found that the crystallite size of the deposit
increases with increasing current density and duty cycle. The crystal
orientation progressively changed from a random texture at 1 A/dm2
to (200) texture at 10 A/dm2. Increasing pulse frequency resulted in
increased texture coefficient and peak intensity of (111) reflection.
An increase in duty cycle resulted in considerable increase in texture
coefficient and peak intensity of (311) reflection. Coatings obtained
at high current densities and duty cycle present a mixed morphology
of small and large grains. Maximum microhardness of 193 Hv was
achieved at 4 A/dm2, 10 Hz and duty cycle of 50%. Nickel coatings
with (200) texture are ductile while (111) texture improves the
microhardness of the coatings.
Abstract: Lateral torsional buckling is a global buckling mode
which should be considered in design of slender structural members
under flexure about their strong axis. It is possible to compute the
load which causes lateral torsional buckling of a beam by finite
element analysis, however, closed form equations are needed in
engineering practice for calculation ease which can be obtained by
using energy method. In lateral torsional buckling applications of
energy method, a proper function for the critical lateral torsional
buckling mode should be chosen which can be thought as the
variation of twisting angle along the buckled beam. Accuracy of the
results depends on how close is the chosen function to the exact
mode. Since critical lateral torsional buckling mode of the cantilever
I-beams varies due to material properties, section properties and
loading case, the hardest step is to determine a proper mode function
in application of energy method. This paper presents an approximate function for critical lateral
torsional buckling mode of doubly symmetric cantilever I-beams.
Coefficient matrices are calculated for concentrated load at free end,
uniformly distributed load and constant moment along the beam
cases. Critical lateral torsional buckling modes obtained by presented
function and exact solutions are compared. It is found that the modes
obtained by presented function coincide with differential equation
solutions for considered loading cases.
Abstract: In this work, repaired crack in 6061- T6 aluminum
plate with composite patches presented, firstly we determine the
displacement, strain and stress, also the first six mode shape of the
plate, secondly we took the same model adding central crack
initiation, which is located in the center of the plate, its seize vary
from 20 mm to 60 mm and we compare the first results with second.
Thirdly we repair various cracks with composite patch (carbon/
epoxy) and for (2 layers, 4 layers). Finally the comparison of stress,
strain, displacement and six first natural frequencies between un-cracked
specimen, crack propagation and composite patch repair.
Abstract: Cost overruns are a persistent problem in oil and gas
megaprojects. Whilst the extant literature is filled with studies on
incidents and causes of cost overruns, underlying theories to explain
their emergence in oil and gas megaprojects are few. Yet, a way to
contain the syndrome of cost overruns is to understand the bases of
‘how and why’ they occur. Such knowledge will also help to develop
pragmatic techniques for better overall management of oil and gas
megaprojects. The aim of this paper is to explain the development of
cost overruns in hydrocarbon megaprojects through the perspective of
chaos theory. The underlying principles of chaos theory and its
implications for cost overruns are examined and practical
recommendations proposed. In addition, directions for future research
in this fertile area provided.
Abstract: The current study focuses on the seismic design of
offshore pipelines against active faults. After an extensive literature
review of the provisions of the seismic norms worldwide and of the
available analytical methods, the study simulates numerically
(through finite-element modeling and strain-based criteria) the
distress of offshore pipelines subjected to PGDs induced by active
normal and reverse seismic faults at the seabed. Factors, such as the
geometrical properties of the fault, the mechanical properties of the
ruptured soil formations, and the pipeline characteristics, are
examined. After some interesting conclusions regarding the seismic
vulnerability of offshore pipelines, potential cost-effective mitigation
measures are proposed taking into account constructability issues.
Abstract: One of the challenges that higher education faces is to
find how to approach the sustainability in an inclusive way to the
student within all the different academic areas, how to move the
sustainable development from the abstract field to the operational
field. This research comes from the ecoliteracy and the pedagogical
praxis as tools for rebuilding the teaching processes inside of
universities. The purpose is to determine and describe which are the
factors involved in the process of learning particularly in the
Greenhouse-School Siembra UV. In the Greenhouse-School Siembra UV, of the University of
Veracruz, are cultivated vegetables, medicinal plants and small
cornfields under the usage of eco-technologies such as hydroponics,
Wickingbed and Hugelkultur, which main purpose is the saving of
space, labor and natural resources, as well as function as agricultural
production alternatives in the urban and periurban zones. The sample was formed with students from different academic
areas and who are actively involved in the greenhouse, as well as
institutes from the University of Veracruz and governmental and nongovernmental
departments. This project comes from a pedagogic praxis approach, from filling
the needs that the different professional profiles of the university
students have. All this with the purpose of generate a pragmatic
dialogue with the sustainability. It also comes from the necessity to
understand the factors that intervene in the students’ praxis. In this
manner is how the students are the fundamental unit in the sphere of
sustainability. As a result, it is observed that those University of Veracruz
students who are involved in the Greenhouse-school, Siembra UV,
have enriched in different levels the sense of urban and periurban
agriculture because of the diverse academic approaches they have
and the interaction between them. It is concluded that the ecotechnologies
act as fundamental tools for ecoliteracy in society,
where it is strengthen the nutritional and food security from a
sustainable development approach.
Abstract: Manufacturing tolerancing is intended to determine
the intermediate geometrical and dimensional states of the part during
its manufacturing process. These manufacturing dimensions also
serve to satisfy not only the functional requirements given in the
definition drawing, but also the manufacturing constraints, for
example geometrical defects of the machine, vibration and the wear
of the cutting tool. The choice of positioning has an important influence on the cost
and quality of manufacture. To avoid this problem, a two-step
approach has been developed. The first step is dedicated to the
determination of the optimum position. As for the second step, a
study was carried out for the tightening effect on the tolerance
interval.
Abstract: Cryosorption pumps are considered safe, quiet, and
ultra-high vacuum production pumps which have their application
from Semiconductor industries to ITER [International Thermonuclear
Experimental Reactor] units. The principle of physisorption of gases
over highly porous materials like activated charcoal at cryogenic
temperatures (below -1500°C) is involved in determining the
pumping speed of gases like Helium, Hydrogen, Argon, and
Nitrogen. This paper aims at providing detailed overview of
development of Cryosorption pump and characterization of different
activated charcoal materials that optimizes the performance of the
pump. Different grades of charcoal were tested in order to determine
the pumping speed of the pump and were compared with
commercially available Varian cryopanel. The results for bare panel,
bare panel with adhesive, cryopanel with pellets, and cryopanel with
granules were obtained and compared. The comparison showed that
cryopanel adhered with small granules gave better pumping speeds
than large sized pellets.
Abstract: This contribution is focused on the methodology for
identifying levels of quality and improving quality through new
logistics model in railway transport. It is oriented on the application
of dynamic quality models, which represent an innovative method of
evaluation quality services. Through this conception, time factor,
expected, and perceived quality in each moment of the transportation
process within logistics chain can be taken into account. Various
models describe the improvement of the quality which emphases the
time factor throughout the whole transportation logistics chain.
Quality of services in railway transport can be determined by the
existing level of service quality, by detecting the causes of
dissatisfaction employees but also customers, to uncover strengths
and weaknesses. This new logistics model is able to recognize critical
processes in logistic chain. It includes service quality rating that must
respect its specific properties, which are unrepeatability,
impalpability, their use right at the time they are provided and
particularly changeability, which is significant factor in the
conditions of rail transport as well. These peculiarities influence the
quality of service regarding the constantly increasing requirements
and that result in new ways of finding progressive attitudes towards
the service quality rating.
Abstract: The paper shows that on transferring sense from the
SL to the TL, the translator’s reading against the grain determines the
creation of a faulty pattern of rendering the original meaning in the
receiving culture which reflects the use of misleading transformative
codes. In this case, the translator is a writer per se who decides what
goes in and out of the book, how the style is to be ciphered and what
elements of ideology are to be highlighted. The paper also proves that
figurative language must not be flattened for the sake of clarity or
naturalness. The missing figurative elements make the translated text
less interesting, less challenging and less vivid which reflects poorly
on the writer. There is a close connection between style and the
writer’s person. If the writer’s style is very much altered in a
translation, the translation is useless as the original writer and his /
her imaginative world can no longer be discovered. The purpose of the paper is to prove that adaptation is a dangerous
tool which leads to variants that sometimes reflect the original less
than the reader would wish to. It contradicts the very essence of the
process of translation which is that of making an original work
available in a foreign language. If the adaptive transformative codes
are so flexible that they encourage the translator to repeatedly leave
out parts of the original work, then a subversive pattern emerges
which changes the entire book. In conclusion, as a result of using adaptation, manipulative or
subversive effects are created in the translated work. This is generally
achieved by adding new words or connotations, creating new figures
of speech or using explicitations. The additional meanings of the
original work are neglected and the translator creates new meanings,
implications, emphases and contexts. Again s/he turns into a new
author who enjoys the freedom of expressing his / her own ideas
without the constraints of the original text. Reading against the grain
is unadvisable during the process of translation and consequently,
following personal common sense becomes essential in the field of
translation as well as everywhere else, so that translation should not
become a source of fantasy.
Abstract: In this article, the radial displacement error correction
capability of a high precision spindle grinding caused by unbalance
force was investigated. The spindle shaft is considered as a flexible
rotor mounted on two sets of angular contact ball bearing. Finite
element methods (FEM) have been adopted for obtaining the
equation of motion of the spindle. In this paper, firstly, natural
frequencies, critical frequencies, and amplitude of the unbalance
response caused by residual unbalance are determined in order to
investigate the spindle behaviors. Furthermore, an optimization
design algorithm is employed to minimize radial displacement of the
spindle which considers dimension of the spindle shaft, the dynamic
characteristics of the bearings, critical frequencies and amplitude of
the unbalance response, and computes optimum spindle diameters
and stiffness and damping of the bearings. Numerical simulation
results show that by optimizing the spindle diameters, and stiffness
and damping in the bearings, radial displacement of the spindle can
be reduced. A spindle about 4 μm radial displacement error can be
compensated with 2 μm accuracy. This certainly can improve the
accuracy of the product of machining.
Abstract: A numerical study is made in a parallel-plate porous
channel subjected to an oscillating flow and an exothermic chemical
reaction on its walls. The flow field in the porous region is modeled
by the Darcy–Brinkman–Forchheimer model and the finite volume
method is used to solve the governing equations. The effects of the
modified Frank-Kamenetskii (FKm) and Damköhler (Dm) numbers,
the amplitude of oscillation (A), and the Strouhal number (St) are
examined. The main results show an increase of heat and mass
transfer rates with A and St, and their decrease with FKm and Dm.
Abstract: Parboiled rice was developed to produce rice, which
has a low glycemic index for diabetics. However, diabetics also have
a chromium (Cr) deficiency. Thus, it is important to fortify rice with
Cr to increase the Cr content. Moreover, parboiled rice becomes
rancid easily and has a musty odor, rendering the rice unfavorable.
Natural herbs such as pandan leaves (Pandanus amaryllifolius
Roxb.), bay leaves (Syzygium polyanthum [Wigh] Walp) and
cinnamon bark powder (Cinnamomon cassia) are commonly added to
food as aroma enhancers. Previous research has shown that these
herbs could improve insulin sensitivity. The purpose of this study
was to evaluate the effect of herbal extract coatings on the cooking
quality and the preference level of chromium fortified - parboiled rice
(CFPR). The rice grain variety used for this experiment was Ciherang
and the fortificant was CrCl3. The three herbal extracts used for
coating the CFPR were cinnamon, pandan and bay leaf, with
concentration variations of 3%, 6%, and 9% (w/w) for each of the
extracts. The samples were analyzed for their alkali spreading value,
cooking time, elongation, water uptake ratio, solid loss, colour and
lightness; and their sensory properties were determined by means of
an organoleptic test. The research showed that coating the CFPR with
pandan and cinnamon extracts at a concentration of 3% each
produced a preferred CFPR. When coated with those herbal extracts
the CFPR had the following cooking quality properties: alkali
spreading value 5 (intermediate gelatinization temperature), cooking
time, 26-27 min, color value, 14.95-15.00, lightness, 42.30 – 44.06,
elongation, 1.53 – 1.54, water uptake ratio , 4.05-4.06, and solid loss,
0.09/100 g – 0.13 g/100 g.
Abstract: The UK is leading in online retail and mobile
adoption. However, there is a dearth of information relating to mobile
apparel retail, and developing an understanding about consumer
browsing and purchase behaviour in m-retail channel would provide
apparel marketers, mobile website and app developers with the
necessary understanding of consumers’ needs. Despite the rapid
growth of mobile retail businesses, no published study has examined
shopping behaviour on fashion mobile apps and websites. A mixed method approach helped to understand why fashion
consumers prefer websites on smartphones, when diverse mobile
apps are also available. The following research methods were
employed: survey, eye-tracking experiments, observation, and
interview with retrospective think aloud. The mobile gaze tracking
device by SensoMotoric Instruments was used to understand
frustrations in navigation and other issues facing consumers in
mobile channel. This method helped to validate and compliment
other traditional user-testing approaches in order to optimize user
experience and enhance the development of mobile retail channel.
The study involved eight participants - females aged 18 to 35 years
old, who are existing mobile shoppers. The participants used the
Topshop mobile app and website on a smart phone to complete a task
according to a specified scenario leading to a purchase. The
comparative study was based on: duration and time spent at different
stages of the shopping journey, number of steps involved and product
pages visited, search approaches used, layout and visual clues, as
well as consumer perceptions and expectations. The results from the data analysis show significant differences in
consumer behaviour when using a mobile app or website on a smart
phone. Moreover, two types of problems were identified, namely
technical issues and human errors. Having a mobile app does not
guarantee success in satisfying mobile fashion consumers. The
differences in the layout and visual clues seem to influence the
overall shopping experience on a smart phone. The layout of search
results on the website was different from the mobile app. Therefore,
participants, in most cases, behaved differently on different
platforms. The number of product pages visited on the mobile app
was triple the number visited on the website due to a limited visibility
of products in the search results. Although, the data on traffic trends
held by retailers to date, including retail sector breakdowns for visits
and views, data on device splits and duration, might seem a valuable
source of information, it cannot explain why consumers visit many
product pages, stay longer on the website or mobile app, or abandon
the basket. A comprehensive list of pros and cons was developed by
highlighting issues for website and mobile app, and recommendations
provided. The findings suggest that fashion retailers need to be aware of
actual consumers’ behaviour on the mobile channel and their expectations in order to offer a seamless shopping experience. Added
to which is the challenge of retaining existing and acquiring new
customers. There seem to be differences in the way fashion
consumers search and shop on mobile, which need to be explored in
further studies.
Abstract: Household waste form a larger proportion of waste
generated across the state, accumulation of organic waste is an
apparent problem and the existing dump sites could be overstress.
Niger state has abundant arable land and water resources thus should
be one of the highest producers of agricultural crops in the country.
However, the major challenge to agricultural sector today is loss of
soil nutrient coupled with high cost of fertilizer. These have
continued to increase the use of fertilizer and decomposed solid waste
for enhance agricultural yield, which have varying effects on the soil
as well a threat to human livelihood. Consequently, vegetable yield
samples from poultry droppings, decomposed household waste
manure, NPK treatments and control from each replication were
subjected to proximate analysis to determine the nutritional and antinutritional
component as well as heavy metal concentration. Data
collected was analyzed using SPSS software and Randomized
complete Block Design means were compared. The result shows that
the treatments do not devoid the concentrations of any nutritional
components while the anti-nutritional analysis proved that NPK had
higher oxalate content than control and organic treats. The
concentration of lead and cadmium are within safe permissible level
while the mercury level exceeded the FAO/WHO maximum
permissible limit for the entire treatments depicts the need for urgent
intervention to minimize mercury levels in soil and manure in order
to mitigate its toxic effect. Thus, eco-agriculture should be widely
accepted and promoted by the stakeholders for soil amendment,
higher yield, strategies for sustainable environmental protection, food
security, poverty eradication, attainment of sustainable development
and healthy livelihood.
Abstract: This study focuses on the hydro-geology and chemical
constituents analysis of Ikogosi Warm Spring waters in South West
Nigeria. Ikogosi warm spring is a global tourist attraction because it
has both warm and cold spring sources. Water samples from the cold
spring, warm spring and the meeting point were collected, analyzed
and the result shows close similarity in temperature, hydrogen iron
concentration (pH), alkalinity, hardness, Calcium, Magnesium,
Sodium, Iron, total dissolved solid and heavy metals. The measured
parameters in the water samples are within World Health
Organisation standards for fresh water. The study of the geology of
the warm spring reveals that the study area is underlain by a group of
slightly migmatised to non-migmatised paraschists and meta-igneous
rocks. Also, concentration levels of selected heavy metals, (Copper,
Cadmium, Zinc, Arsenic and Cromium) were determined in the water
(ppm) samples. Chromium had the highest concentration value of
1.52ppm (an average of 49.67%) and Cadmium had the lowest
concentration with value of 0.15ppm (an average of 4.89%).
Comparison of these results showed that, their mean levels are within
the standard values obtained in Nigeria. It can be concluded that both
warm and spring water are safe for drinking.
Abstract: The present study examined how translation teachers
develop final tests as measures for checking on the quality of
students’ academic translation in Iranian context. To achieve this
goal, thirty experienced male and female translation teachers from the
four types of the universities offering the program were invited to an
in-depth 30-minute one-session semi-structured interview. The
responses provided showed how much discrepancy exists among the
Iranian translation teachers (as developers of final translation tests),
who are least informed with the current translation evaluation
methods. It was also revealed that the criteria they use for developing
such tests and scoring student translations are not theory-driven but
are highly subjective, mainly based on their personal experience and
intuition. Hence, the quality and accountability of such tests are under
serious question. The results also confirmed that the dominant
method commonly and currently practiced is the purely essay-type
format. To remedy the situation, some suggestions are in order. As
part of the solution, to improve the reliability and validity of such
tests, the present summative, product-oriented evaluation should be
accompanied with some formative, process-oriented methods of
evaluation. Training the teachers and helping them get acquainted
with modern principles of translation evaluation as well as the
existing models, and rating scales does improve the quality of
academic translation evaluation.
Abstract: The need to save time and cost of soil testing at the
planning stage of road work has necessitated developing predictive
models. This study proposes a model for predicting the dry density of
lateritic soils stabilized with corn cob ash (CCA) and blended cement
- CCA. Lateritic soil was first stabilized with CCA at 1.5, 3.0, 4.5 and
6% of the weight of soil and then stabilized with the same
proportions as replacement for cement. Dry density, specific gravity,
maximum degree of saturation and moisture content were determined
for each stabilized soil specimen, following standard procedure.
Polynomial equations containing alpha and beta parameters for CCA
and blended CCA-cement were developed. Experimental values were
correlated with the values predicted from the Matlab curve fitting
tool, and the Solver function of Microsoft Excel 2010. The correlation
coefficient (R2) of 0.86 was obtained indicating that the model could
be accepted in predicting the maximum dry density of CCA stabilized
soils to facilitate quick decision making in roadworks.