Abstract: In the process of recovering oil in weak sandstone formations, the strength of sandstones around the wellbore is weakened due to the increase of effective stress/load from the completion activities around the cavity. The weakened and de-bonded sandstone may be eroded away by the produced fluid, which is termed sand production. It is one of the major trending subjects in the petroleum industry because of its significant negative impacts, as well as some observed positive impacts. For efficient sand management therefore, there has been need for a reliable study tool to understand the mechanism of sanding. One method of studying sand production is the use of the widely recognized Discrete Element Method (DEM), Particle Flow Code (PFC3D) which represents sands as granular individual elements bonded together at contact points. However, there is limited knowledge of the particle-scale behavior of the weak sandstone, and the parameters that affect sanding. This paper aims to investigate the reliability of using PFC3D and a simple Darcy flow in understanding the sand production behavior of a weak sandstone. An isotropic tri-axial test on a weak oil sandstone sample was first simulated at a confining stress of 1MPa to calibrate and validate the parallel bond models of PFC3D using a 10m height and 10m diameter solid cylindrical model. The effect of the confining stress on the number of bonds failure was studied using this cylindrical model. With the calibrated data and sample material properties obtained from the tri-axial test, simulations without and with fluid flow were carried out to check on the effect of Darcy flow on bonds failure using the same model geometry. The fluid flow network comprised of every four particles connected with tetrahedral flow pipes with a central pore or flow domain. Parametric studies included the effects of confining stress, and fluid pressure; as well as validating flow rate – permeability relationship to verify Darcy’s fluid flow law. The effect of model size scaling on sanding was also investigated using 4m height, 2m diameter model. The parallel bond model successfully calibrated the sample’s strength of 4.4MPa, showing a sharp peak strength before strain-softening, similar to the behavior of real cemented sandstones. There seems to be an exponential increasing relationship for the bigger model, but a curvilinear shape for the smaller model. The presence of the Darcy flow induced tensile forces and increased the number of broken bonds. For the parametric studies, flow rate has a linear relationship with permeability at constant pressure head. The higher the fluid flow pressure, the higher the number of broken bonds/sanding. The DEM PFC3D is a promising tool to studying the micromechanical behavior of cemented sandstones.
Abstract: The objective of this study is to uncover the basic business-forces that necessitated the survival and sustainable performance of the medium scale contractors in the South African construction market. This study is essential as it set to contribute towards long-term strategic solutions for combating the incessant failure of start-ups construction organizations within South African. The study used a qualitative research methodology; as the most appropriate approach to elicit and understand, and uncover the phenomena that are basic business-forces for the active contractors in the market. The study also adopted a phenomenological study approach; and in-depth interviews were conducted with 20 medium scale contractors in Port Elizabeth, South Africa, between months of August to October 2015. This allowed for an in-depth understanding of the critical and basic business-forces that influenced their survival and performance beyond the first five years of business operation. Findings of the study showed that for potential contractors (startups), to survival in the competitive business environment such as construction industry, they must possess the basic business-forces. These forces are educational knowledge in construction and business management related disciplines, adequate industrial experiences, competencies and capabilities to delivery excellent services and products as well as embracing the spirit of entrepreneurship. Convincingly, it can be concluded that the strategic approach to minimize the endless failure of startups construction businesses; the potential construction contractors must endeavoring to access and acquire the basic educationally knowledge, training and qualification; need to acquire industrial experiences in collaboration with required competencies, capabilities and entrepreneurship acumen. Without these basic business-forces as been discovered in this study, the majority of the contractors gaining entrance in the market will find it difficult to develop and grow a competitive and sustainable construction organization in South Africa.
Abstract: In many practical situations, bubbles are dispersed in a
liquid phase. Understanding these complex bubbly flows is therefore
a key issue for applications such as shell and tube heat exchangers,
mineral flotation and oxidation in water treatment. Although a large
body of work exists for bubbles rising in an unbounded medium,
that of bubbles rising in constricted geometries has received less
attention. The particular case of a bubble sliding underneath an
inclined surface is common to two-phase flow systems. The current
study intends to expand this knowledge by performing experiments
to quantify the streamwise flow structures associated with a single
sliding air bubble under an inclined surface in quiescent water. This
is achieved by means of two-dimensional, two-component particle
image velocimetry (PIV), performed with a continuous wave laser
and high-speed camera. PIV vorticity fields obtained in a plane
perpendicular to the sliding surface show that there is significant bulk
fluid motion away from the surface. The associated momentum of the
bubble means that this wake motion persists for a significant time
before viscous dissipation. The magnitude and direction of the flow
structures in the streamwise measurement plane are found to depend
on the point on its path through which the bubble enters the plane.
This entry point, represented by a phase angle, affects the nature and
strength of the vortical structures. This study reconstructs the vorticity
field in the wake of the bubble, converting the field at different
instances in time to slices of a large-scale wake structure. This is, in
essence, Taylor’s ”frozen turbulence” hypothesis. Applying this to the
vorticity fields provides a pseudo three-dimensional representation
from 2-D data, allowing for a more intuitive understanding of the
bubble wake. This study provides insights into the complex dynamics
of a situation common to many engineering applications, particularly
shell and tube heat exchangers in the nucleate boiling regime.
Abstract: The sun is an inexhaustible source and harness its potential both for heating and power generation is one of the most promising and necessary alternatives, mainly due to environmental issues. However, it should be noted that this has always been present in the generation of energy on earth, only indirectly, since it is responsible for virtually all other energy sources, such as generating source of evaporation of the water cycle, allowing the impoundment and the consequent generation of electricity (hydroelectric power); winds are caused by atmospheric induction caused by large scale solar radiation; petroleum, coal and natural gas were generated from waste plants and animals that originally derived energy required for their development of solar radiation. This paper presents a study on the feasibility of using solar energy for water heating in homes. A simplified methodology developed for formulation of solar heating operation model of water in alternative systems of solar energy in Brazil, and compared it to that in the international market. Across this research, it was possible to create new paradigms for alternative applications to the use of solar energy.
Abstract: Approximately 10,000 different types of dyes and
pigments are being used in various industrial applications yearly,
which include the textile and printing industries. However, these dyes
are difficult to degrade naturally once they enter the aquatic system.
Their high persistency in natural environment poses a potential health
hazard to all form of life. Hence, there is a need for alternative dye
removal strategy in the environment via bioremediation. In this study,
fungi laccase is investigated via commercial agar dyes plates and
submerged fermentation to explore the application of fungi laccase in
textile dye wastewater treatment. Two locally isolated basidiomycetes
were screened for laccase activity using media added with commercial
dyes such as 2, 2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid
(ABTS), guaiacol and Remazol Brillant Blue R (RBBR). Isolate TBB3
(1.70±0.06) and EL2 (1.78±0.08) gave the highest results for ABTS
plates with the appearance of greenish halo on around the isolates.
Submerged fermentation performed on Isolate TBB3 with the
productivity 3.9067 U/ml/day, whereas the laccase activity for Isolate
EL2 was much lower (0.2097 U/ml/day). As isolate TBB3 showed
higher laccase production, it was subjected to molecular
characterization by DNA isolation, PCR amplification and sequencing
of ITS region of nuclear ribosomal DNA. After being compared with
other sequences in National Center for Biotechnology Information
(NCBI database), isolate TBB3 is probably from species Trametes
hirsutei. Further research work can be performed on this isolate by
upscale the production of laccase in order to meet the demands of the
requirement for higher enzyme titer for the bioremediation of textile
dyes.
Abstract: In this paper, we analyze NEtwork MObility (NEMO) supporting problems in Content-Centric Networking (CCN), and propose the CCN-NEMO which can well support the deployment of the content-centric paradigm in large-scale mobile Internet. The CCN-NEMO extends the signaling message of the basic CCN protocol, to support the mobility discovery and fast trigger of Interest re-issuing during the network mobility. Besides, the Mobile Router (MR) is extended to optimize the content searching and relaying in the local subnet. These features can be employed by the nested NEMO to maximize the advantages of content retrieving with CCN. Based on the analysis, we compare the performance on handover latency between the basic CCN and our proposed CCN-NEMO. The results show that our scheme can facilitate the content-retrieving in the NEMO scenario with improved performance.
Abstract: In this paper, we present an analytical method for
analysis of nano-scale spherical shell subjected to thermo-mechanical
shocks based on nonlocal elasticity theory. Thermo-mechanical
properties of nano shpere is assumed to be temperature dependent.
Governing partial differential equation of motion is solved
analytically by using Laplace transform for time domain and power
series for spacial domain. The results in Laplace domain is
transferred to time domain by employing the fast inverse Laplace
transform (FLIT) method. Accuracy of present approach is assessed
by comparing the the numerical results with the results of published
work in literature. Furtheremore, the effects of non-local parameter
and wall thickness on the dynamic characteristics of the nano-sphere
are studied.
Abstract: Problem of food preservation is extremely important
for mankind. Viscous damage ("illness") of bread results from
development of Bacillus spp. bacteria. High temperature resistant
spores of this microorganism are steady against 120°C) and remain in
bread during pastries, potentially causing spoilage of the final
product. Scientists are interested in further characterization of bread
spoiling Bacillus spp. species. Our aim was to find weather yeast
Saccharomyces cerevisiae strains that are able to produce natural
antimicrobial killer factor can preserve bread illness. By diffusion
method, we showed yeast antagonistic activity against spore-forming
bacteria. Experimental technological parameters were the same as for
bakers' yeasts production on the industrial scale. Risograph test
during dough fermentation demonstrated gas production. The major
finding of the study was a clear indication of the presence of killer
yeast strain antagonistic activity against rope in bread causing
bacteria. After demonstrating antagonistic effect of S. cerevisiae on
bacteria using solid nutrient medium, we tested baked bread under
provocative conditions. We also measured formation of carbon
dioxide in the dough, dough-making duration and quality of the final
products, when using different strains of S. cerevisiae. It is
determined that the use of yeast S. cerevisiae RCAM 01730 killer
strain inhibits appearance of rope in bread. Thus, natural yeast
antimicrobial killer toxin, produced by some S. cerevisiae strains is
an anti-rope in bread protector.
Abstract: The aim of this study is to compare abused and normal male students in Tehran guidance schools with emphasis on the co-dependency of their mothers. The method of this study is based on survey method and comparison (Ex-Post Facto). The method of sampling is also multi-stage cluster. Accordingly, we did sampling from secondary schools of education and training in Tehran, including 12 schools with levels of first, second and third. Each of the schools represents the three – high, medium and low- economic and social conditions. In the following, three classes from every school and 20 students from each class were randomly selected. By (CTQ) abused and normal students were separated that 670 children were recognized as normal and 50 children as abused. Then, 50 children were randomly selected from normal group and compared with abused group. Using Spanned-Fischer Co-dependency Scale, we compared mothers of abused and normal students. The results showed that mothers of the abused children have higher co- dependency average comparing to the mothers of the normal children.
Abstract: The purpose of this study is to investigate the efficacy of the solution-focused brief therapy on improving the psychological wellbeing of family supervisor woman. This study has been carried out by semi-experimental method and in the form of pre-test, post-test performance on two groups (experimental and control), so that one sample group of 30 individuals was randomly achieved and were randomly divided in two groups of experimental (n=15) and control (n=15). To collect data, Ryff scale psychological wellbeing was used. After conducting pre-test (RSPWB) for two experimental and control groups, Solution-focused brief therapy interference was conducted on the experimental group during five two-hour sessions. Finally, Ryff scale psychological wellbeing was reused for the two groups as post-test and achieved outcomes that were analyzed using covariance. The results indicated that the significant increase of average marks of the experimental group in psychological wellbeing had better function than that of the control group. Finally, solution-focused brief therapy for improving psychological well-being of family supervisor women has a suitable capability and could be used in this way.
Abstract: The effectiveness of microchannels in enhancing heat
transfer has been demonstrated in the semiconductor industry. In
order to tap the microscale heat transfer effects into macro
geometries, overcoming the cost and technological constraints,
microscale passages were created in macro geometries machined
using conventional fabrication methods. A cylindrical insert was
placed within a pipe, and geometrical profiles were created on the
outer surface of the insert to enhance heat transfer under steady-state
single-phase liquid flow conditions. However, while heat transfer
coefficient values of above 10 kW/m2·K were achieved, the heat
transfer enhancement was accompanied by undesirable pressure drop
increment. Therefore, this study aims to address the high pressure
drop issue using Constructal theory, a universal design law for both
animate and inanimate systems. Two designs based on Constructal theory were developed to study
the effectiveness of Constructal features in reducing the pressure drop
increment as compared to parallel channels, which are commonly
found in microchannel fabrication. The hydrodynamic and heat
transfer performance for the Tree insert and Constructal fin (Cfin)
insert were studied using experimental methods, and the underlying
mechanisms were substantiated by numerical results. In technical
terms, the objective is to achieve at least comparable increment in
both heat transfer coefficient and pressure drop, if not higher
increment in the former parameter. Results show that the Tree insert improved the heat transfer
performance by more than 16 percent at low flow rates, as compared
to the Tree-parallel insert. However, the heat transfer enhancement
reduced to less than 5 percent at high Reynolds numbers. On the
other hand, the pressure drop increment stayed almost constant at 20
percent. This suggests that the Tree insert has better heat transfer
performance in the low Reynolds number region. More importantly,
the Cfin insert displayed improved heat transfer performance along
with favourable hydrodynamic performance, as compared to Cfinparallel
insert, at all flow rates in this study. At 2 L/min, the
enhancement of heat transfer was more than 30 percent, with 20
percent pressure drop increment, as compared to Cfin-parallel insert.
Furthermore, comparable increment in both heat transfer coefficient
and pressure drop was observed at 8 L/min. In other words, the Cfin
insert successfully achieved the objective of this study. Analysis of the results suggests that bifurcation of flows is
effective in reducing the increment in pressure drop relative to heat
transfer enhancement. Optimising the geometries of the Constructal
fins is therefore the potential future study in achieving a bigger stride
in energy efficiency at much lower costs.
Abstract: Fe-2%Mn-0.5%Si-0.2C steel was welded and corroded
at 600, 700 and 800oC for 20 h in 1 atm of N2/H2S/H2O-mixed gas in
order to characterize the high-temperature corrosion behavior of the
welded joint. Corrosion proceeded fast and almost linearly. It
increased with an increase in the corrosion temperature. H2S formed
FeS owing to sulfur released from H2S. The scales were fragile and
nonadherent.
Abstract: The rapid growth of the human population and the
environmental degradation associated with increased consumption of
resources raises concerns on sustainability. Social sustainability
constitutes one of the three dimensions of sustainability together with
environmental and economic dimensions. Even though there is not an
agreement on what social sustainability consists of, it is a well known
fact that it necessitates user participation. The fore, this study aims to
observe and analyze the role of user participation on social
sustainability. In this paper, the links between user participation and indicators of
social sustainability have been searched. In order to achieve this, first
of all a literature review on social sustainability has been done;
accordingly, the information obtained from researches has been used
in the evaluation of the projects conducted in the developing
countries considering user participation. These examples are taken as
role models with pros and cons for the development of the checklist
for the evaluation of the case studies. Furthermore, a case study over
the post earthquake residential settlements in Turkey have been
conducted. The case study projects are selected considering different building
scales (differing number of residential units), scale of the problem
(post-earthquake settlements, rehabilitation of shanty dwellings) and
the variety of users (differing socio-economic dimensions). Decisionmaking,
design, building and usage processes of the selected projects
and actors of these processes have been investigated in the context of
social sustainability. The cases include: New Gourna Village by
Hassan Fathy, Quinta Monroy dwelling units conducted in Chile by
Alejandro Aravena and Beyköy and Beriköy projects in Turkey
aiming to solve the problem of housing which have appeared after the
earthquake happened in 1999 have been investigated. Results of the
study possible links between social sustainability indicators and user
participation and links between user participation and the
peculiarities of place. Results are compared and discussed in order to find possible
solutions to form social sustainability through user participation.
Results show that social sustainability issues depend on communities'
characteristics, socio-economic conditions and user profile but user
participation has positive effects on some social sustainability
indicators like user satisfaction, a sense of belonging and social
stability.
Abstract: Sentiment analysis (SA) has received growing
attention in Arabic language research. However, few studies have yet
to directly apply SA to Arabic due to lack of a publicly available
dataset for this language. This paper partially bridges this gap due to
its focus on one of the Arabic dialects which is the Saudi dialect. This
paper presents annotated data set of 4700 for Saudi dialect sentiment
analysis with (K= 0.807). Our next work is to extend this corpus and
creation a large-scale lexicon for Saudi dialect from the corpus.
Abstract: Reinforced earth structures are generally subjected to cyclic loading generated from earthquakes. This paper presents a summary of the results and analyses of a testing program carried out in a large-scale multi-function geosynthetic testing apparatus that accommodates soil samples up to 1.0 m3. This apparatus performs different shear and pullout tests under both static and cyclic loading. The testing program was carried out to investigate the controlling factors affecting soil/geogrid interaction under cyclic loading. The extensibility of the geogrids, the applied normal stresses, the characteristics of the cyclic loading (frequency, and amplitude), and initial static load within the geogrid sheet were considered in the testing program. Based on the findings of the testing program, the effect of these parameters on the pullout resistance of geogrids, as well as the displacement mobility under cyclic loading were evaluated. Conclusions and recommendations for the design of reinforced earth walls under cyclic loading are presented.
Abstract: Large scale Indian manufacturers started
implementing Six Sigma to their supply core to fulfill the endless
need of high quality products. As well, they initiated encouraging
their suppliers to apply the well-ascertain SS management practice
and kept no resource for supplier enterprises, generally small midsized
enterprises to think for the admittance of Six Sigma as a quality
promotion drive. There are many issues to study for requisite changes
before the introduction of Six Sigma in auto SMEs. This paper
converges on impeding factors while implementing SS drive and also
pinpoints the gains achieved through successful implementation. The
result of this study suggest some operational guidelines for effective
implementation of Six Sigma from evidences acquired through
research questionnaire and interviews with industrial professionals,
apportioned to assort auto sector mid-sized enterprises (MSEs) in
India.
Abstract: Ultrasonic metal welding has been the subject of ongoing research and development, most recently concentrating on metal joining in miniature devices, for example to allow solder-free wire bonding. As well as at the small scale, there are also opportunities to research the joining of thicker sheet metals and to widen the range of similar and dissimilar materials that can be successfully joined using this technology. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal spot welding device. The ultrasonic metal spot welding horn is modelled using finite element analysis (FEA) and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered effectively to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. The results show how the weld strength is particularly sensitive to the combination of clamping force and ultrasonic vibration amplitude of the welding tip, but there are optimal combinations of these and also limits that must be clearly identified.
Abstract: The objective of this research is to develop a general technique so that one may predict the dynamic behaviour of a three-dimensional scale crane model subjected to time-dependent moving point forces by means of conventional finite element computer packages. To this end, the whole scale crane model is divided into two parts: the stationary framework and the moving substructure. In such a case, the dynamic responses of a scale crane model can be predicted from the forced vibration responses of the stationary framework due to actions of the four time-dependent moving point forces induced by the moving substructure. Since the magnitudes and positions of the moving point forces are dependent on the relative positions between the trolley, moving substructure and the stationary framework, it can be found from the numerical results that the time histories for the moving speeds of the moving substructure and the trolley are the key factors affecting the dynamic responses of the scale crane model.
Abstract: Discussing the nexus between global health policy and local practices, this article addresses the recent Ebola outbreak as a role model for narrative co-constructions of epidemic risk. We will demonstrate in how far a theory-driven and methodologically rooted analysis of narrativity can help to improve mechanisms of prevention and intervention whenever epidemic risk needs to be addressed locally in order to contribute to global health. Analyzing the narrative transformation of Ebola, we will also address issues of transcultural problem-solving and of normative questions at stake. In this regard, we seek to contribute to a better understanding of a key question of global health and justice as well as to the underlying ethical questions. By highlighting and analyzing the functions of narratives, this paper provides a translational approach to refine our practices by which we address epidemic risk, be it on the national, the transnational or the global scale.
Abstract: The increasing availability of information about earth
surface elevation (Digital Elevation Models DEM) generated from
different sources (remote sensing, Aerial Images, Lidar) poses the
question about how to integrate and make available to the most than
possible audience this huge amount of data. In order to exploit the potential of 3D elevation representation the
quality of data management plays a fundamental role. Due to the high
acquisition costs and the huge amount of generated data, highresolution
terrain surveys tend to be small or medium sized and
available on limited portion of earth. Here comes the need to merge
large-scale height maps that typically are made available for free at
worldwide level, with very specific high resolute datasets. One the
other hand, the third dimension increases the user experience and the
data representation quality, unlocking new possibilities in data
analysis for civil protection, real estate, urban planning, environment
monitoring, etc. The open-source 3D virtual globes, which are
trending topics in Geovisual Analytics, aim at improving the
visualization of geographical data provided by standard web services
or with proprietary formats. Typically, 3D Virtual globes like do not
offer an open-source tool that allows the generation of a terrain
elevation data structure starting from heterogeneous-resolution terrain
datasets. This paper describes a technological solution aimed to set
up a so-called “Terrain Builder”. This tool is able to merge
heterogeneous-resolution datasets, and to provide a multi-resolution
worldwide terrain services fully compatible with CesiumJS and
therefore accessible via web using traditional browser without any
additional plug-in.