Abstract: Among other traditional and non-traditional
additives, polymers have shown an efficient performance in the field
and improved sustainability. Polyacrylamide (PAM) is one such
additive that has demonstrated many advantages including a
reduction in permeability, an increase in durability and the provision
of strength characteristics. However, information about its effect on
the improved geotechnical characteristics is very limited to the field
performance monitoring. Therefore, a laboratory investigation was
carried out to examine the basic and engineering behaviors of three
types of soils treated with a PAM additive. The results showed an
increase in dry density and unconfined compressive strength for all
the soils. The results further demonstrated an increase in unsoaked
CBR and a reduction in permeability for all stabilized samples.
Abstract: The soil profile at site of the bridge project includes soft fine grained soil layer located between 5.0 m to 11.0 m in depth, it has high water content, low SPT no., and low bearing capacity. The clay layer induces high settlement due to surcharge application of earth embankment at ramp T1, ramp T2, and ramp T3 especially at heights from 9m right 3m. Calculated settlement for embankment heights less than 3m may be accepted regarding Saudi Code for soil and foundation. The soil and groundwater at the project site comprise high contents of sulfates and chlorides of high aggressively on concrete and steel bars, respectively. Regarding results of the study, it has been recommended to use stone column piles or new technology named PCC piles as soil improvement to improve the bearing capacity of the weak layer. The new technology is cast in-situ thin wall concrete pipe piles (PCC piles), it has economically advantageous and high workability. The technology can save time of implementation and cost of application is almost 30% of other types of piles.
Abstract: Healthcare waste management continues to present an
array of challenges for developing countries, and Liberia is of no
exception. There is insufficient information available regarding the
generation, handling, and disposal of health care waste. This face
serves as an impediment to healthcare management schemes. The
specific objective of this study is to present an evaluation of the
current health care management practices in Liberia. It also presented
procedures, techniques used, methods of handling, transportation, and
disposal methods of wastes as well as the quantity and composition
of health care waste. This study was conducted as an investigative
case study, covering three different health care facilities; a hospital, a
health center, and a clinic in Monrovia, Montserrado County. The
average waste generation was found to be 0-7kg per day at the clinic
and health center and 8-15kg per/day at the hospital. The composition
of the waste includes hazardous and non-hazardous waste i.e. plastic,
papers, sharps, and pathological elements etc. Nevertheless, the
investigation showed that the healthcare waste generated by the
surveyed healthcare facilities were not properly handled because of
insufficient guidelines for separate collection, and classification, and
adequate methods for storage and proper disposal of generated
wastes. This therefore indicates that there is a need for improvement
within the healthcare waste management system to improve the
existing situation.
Abstract: Despite the benefits of innovation diffusion in the
South African public service, implementation thereof seems to be
problematic, particularly with regard to e-governance which would
enhance the quality of service delivery, especially accessibility,
choice, and mode of operation. This paper reports on differences
between the public service and the private sector in terms of
innovation diffusion. Innovation diffusion will be investigated to
explore identified obstacles that are hindering successful
implementation of e-governance. The research inquiry is underpinned
by the diffusion of innovation theory, which is premised on the
assumption that innovation has a distinct channel, time, and mode of
adoption within the organisation. A comparative thematic document
analysis was conducted to investigate organisational differences with
regard to innovation diffusion. A similar approach has been followed
in other countries, where the same conceptual framework has been
used to guide document analysis in studies in both the private and the
public sectors. As per the recommended conceptual framework, three
organisational characteristics were emphasised, namely the external
characteristics of the organisation, the organisational structure, and
the inherent characteristics of the leadership. The results indicated
that the main difference in the external characteristics lies in the
focus and the clientele of the private sector. With regard to
organisational structure, private organisations have veto power,
which is not the case in the public service. Regarding leadership,
similarities were observed in social and environmental responsibility
and employees’ attitudes towards immediate supervision. Differences
identified included risk taking, the adequacy of leadership
development, organisational approaches to motivation and
involvement in decision making, and leadership style. Due to the
organisational differences observed, it is recommended that
differentiated strategies be employed to ensure effective innovation
diffusion, and ultimately e-governance. It is recommended that the
results of this research be used to stimulate discussion on ways to
improve collaboration between the mentioned sectors, to capitalise on
the benefits of each sector.
Abstract: The effect of upstream surface roughness over a
smooth forward facing step in an open channel was investigated
using a particle image velocimetry technique. Three different
upstream surface topographies consisting of hydraulically smooth
wall, sandpaper 36 grit and sand grains were examined. Besides the
wall roughness conditions, all other upstream flow characteristics
were kept constant. It was also observed that upstream roughness
decreased the approach velocity by 2% and 10% but increased the
turbulence intensity by 14% and 35% at the wall-normal distance
corresponding to the top plane of the step compared to smooth
upstream. The results showed that roughness decreased the
reattachment lengths by 14% and 30% compared to smooth upstream.
Although the magnitudes of maximum positive and negative
Reynolds shear stress in separated and reattached region were 0.02Ue
for all the cases, the physical size of both the maximum and
minimum contour levels were decreased by increasing upstream
roughness.
Abstract: By using an adequate thermal barrier coating in
buildings the energy saving will be happened. In this study, a range
of wall paints with different absorption coefficient in different
climates has been investigated. In order to study these effects, heating
and cooling loads of a common building with different ordinary
paints and paint with mineral coating have been calculated. The
effect of building paint in different climatic condition was studied
and comparison was done between ordinary paints and paint with
mineral insulators in temperate climate to obtain optimized energy
consumption. The results have been shown that coatings with
inorganic micro particles as insulation reduce the energy
consumption of buildings around 14%.
Abstract: Flue gas desulfurization gypsum (FGD) is a waste
material arouse from coal power plants. Hydroxyapatite (HAP) is a
biomaterial with porous structure. In this study, FGD gypsum which
retrieved from coal power plant in Turkey was characterized and
HAP particles which can be used as an adsorbent in wastewater
treatment application were synthesized from the FGD gypsum. The
raw materials are characterized by using X Ray Diffraction (XRD)
and Fourier transform infrared spectroscopy (FT-IR) techniques and
produced HAP are characterized by using XRD. As a result, HAP
particles were synthesized at the molar ratio of 5:10, 5:15, 5:20, 5:24,
at room temperature, in alkaline medium (pH=11) and in 1 hour-reaction
time. Among these conditions, 5:20 had the best result.
Abstract: Digital technologies offer many opportunities in the
design and implementation of brand communication and advertising.
Augmented reality (AR) is an innovative technology in marketing
communication that focuses on the fact that virtual interaction with a
product ad offers additional value to consumers. AR enables
consumers to obtain (almost) real product experiences by the way of
virtual information even before the purchase of a certain product.
Aim of AR applications in relation with advertising is in-depth
examination of product characteristics to enhance product knowledge
as well as brand knowledge. Interactive design of advertising
provides observers with an intense examination of a specific
advertising message and therefore leads to better brand knowledge.
The elaboration likelihood model and the central route to persuasion
strongly support this argumentation. Nevertheless, AR in brand
communication is still in an initial stage and therefore scientific
findings about the impact of AR on information processing and brand
attitude are rare. The aim of this paper is to empirically investigate
the potential of AR applications in combination with traditional print
advertising. To that effect an experimental design with different
levels of interactivity is built to measure the impact of interactivity of
an ad on different variables o advertising effectiveness.
Abstract: In this paper, a desiccant solar unit for air
conditioning and desalination is presented first. Secondly, a dynamic
modelling study of the desiccant wheel is developed. After that, a
simulation study and an experimental investigation of the behaviour
of desiccant wheel are developed. The experimental investigation is
done in the chamber of commerce in Freiburg-Germany. Indeed, the
variations of calculated and measured temperatures and specific
humidity of dehumidified and rejected air are presented where a good
agreement is found when comparing the model predictions with
experimental data under the considered range of operating conditions.
Finally, the study of the compartments of desalination and water
condensation shows that the unit can produce an acceptable quantity
of water at the same time of the air conditioning operation.
Abstract: Effect of Zn addition on the microstructure and
mechanical properties of Mg-Zn alloys with Zn contents from 6 to 10
weight percent was investigated in this study. Through calculation of
phase equilibria of Mg-Zn alloys, carried out by using FactSage® and
FTLite database, solution treatment temperature was decided as
temperatures from 300 to 400oC, where supersaturated solid solution
can be obtained. Solid solution treatment of Mg-Zn alloys was
successfully conducted at 380oC and supersaturated microstructure
with all beta phase resolved into matrix was obtained. After solution
treatment, hot rolling was successfully conducted by reduction of
60%. Compression and tension tests were carried out at room
temperature on the samples as-cast, solution treated, hot-rolled and
recrystallized after rolling. After solid solution treatment, each alloy
was annealed at temperatures of 180 and 200oC for time intervals from
1 min to 48 hrs and hardness of each condition was measured by
micro-Vickers method. Peak aging conditions were deduced as at the
temperature of 200oC for 10 hrs. By addition of Zn by 10 weight
percent, hardness and strength were enhanced.
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: The exploitation of flow pulsation in micro- and
mini-channels is a potentially useful technique for enhancing cooling
of high-end photonics and electronics systems. It is thought that
pulsation alters the thickness of the hydrodynamic and thermal
boundary layers, and hence affects the overall thermal resistance
of the heat sink. Although the fluid mechanics and heat transfer
are inextricably linked, it can be useful to decouple the parameters
to better understand the mechanisms underlying any heat transfer
enhancement. Using two-dimensional, two-component particle image
velocimetry, the current work intends to characterize the heat transfer
mechanisms in pulsating flow with a mean Reynolds number of
48 by experimentally quantifying the hydrodynamics of a generic
liquid-cooled channel geometry. Flows circulated through the test
section by a gear pump are modulated using a controller to achieve
sinusoidal flow pulsations with Womersley numbers of 7.45 and
2.36 and an amplitude ratio of 0.75. It is found that the transient
characteristics of the measured velocity profiles are dependent on the
speed of oscillation, in accordance with the analytical solution for
flow in a rectangular channel. A large velocity overshoot is observed
close to the wall at high frequencies, resulting from the interaction
of near-wall viscous stresses and inertial effects of the main fluid
body. The steep velocity gradients at the wall are indicative of
augmented heat transfer, although the local flow reversal may reduce
the upstream temperature difference in heat transfer applications.
While unsteady effects remain evident at the lower frequency, the
annular effect subsides and retreats from the wall. The shear rate at
the wall is increased during the accelerating half-cycle and decreased
during deceleration compared to steady flow, suggesting that the flow
may experience both enhanced and diminished heat transfer during
a single period. Hence, the thickness of the hydrodynamic boundary
layer is reduced for positively moving flow during one half of the
pulsation cycle at the investigated frequencies. It is expected that the
size of the thermal boundary layer is similarly reduced during the
cycle, leading to intervals of heat transfer enhancement.
Abstract: Surface characteristics of Bacillus megaterium strain
were investigated; zeta potential, FTIR and contact angle were
measured. Surface energy components including Lifshitz-van der
Waals, Hamaker constant, and acid/base components (Lewis
acid/Lewis base) were calculated from the contact angle data. The
results showed that the microbial cells were negatively charged over
all pH regions with high values at alkaline region. A hydrophilic
nature for the strain was confirmed by contact angle and free energy
of adhesion between microbial cells. Adsorption affinity of the strain
toward dolomite was studied at different pH values. The results
showed that the cells had a high affinity to dolomite at acid pH
comparing to neutral and alkaline pH. Extended DLVO theory was
applied to calculate interaction energy between B. megaterium cells
and dolomite particles. The adsorption results were in agreement with
the results of Extended DLVO approach. Surface changes occurred
on dolomite surface after the bio-treatment were monitored; contact
angle decreased from 69° to 38° and the mineral’s floatability
decreased from 95% to 25% after the treatment.
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: The layered structure LiNi1/3Co1/3Mn1/3-xAlxO2 (x = 0 ~
0.04) series cathode materials were synthesized by a carbonate
co-precipitation method, followed by a high temperature calcination
process. The influence of Al substitution on the microstructure and
electrochemical performances of the prepared materials was
investigated by X-Ray diffraction (XRD), scanning electron
microscopy (SEM), and galvanostatic charge/discharge test. The
results show that the LiNi1/3Co1/3Mn1/3-xAlxO2 has a well-ordered
hexagonal α-NaFeO2 structure. Although the discharge capacity of
Al-doped samples decreases as x increases,
LiNi1/3Co1/3Mn1/3-0.02Al0.02O2 exhibits superior capacity retention at
high voltage (4.6 V). Therefore, LiNi1/3Co1/3Mn1/3-0.02Al0.02O2 is a
promising material for “green” vehicles.
Abstract: The irradiation of polymeric materials has received
much attention because it can produce diverse changes in chemical
structure and physical properties. Thus, studying the chemical and
structural changes of polymers is important in practice to achieve
optimal conditions for the modification of polymers. The effect of
gamma irradiation on the crystalline structure of poly(vinylidene
fluoride) (PVDF) has been investigated using differential scanning
calorimetry (DSC) and X-ray diffraction techniques (XRD). Gamma
irradiation was carried out in atmosphere air with doses between 100
kGy at 3,000 kGy with a Co-60 source. In the melting thermogram of
the samples irradiated can be seen a bimodal melting endotherm is
detected with two melting temperature. The lower melting
temperature is attributed to melting of crystals originally present and
the higher melting peak due to melting of crystals reorganized upon
heat treatment. These results are consistent with those obtained by
XRD technique showing increasing crystallinity with increasing
irradiation dose, although the melting latent heat is decreasing.
Abstract: This paper investigates the effects of breaks in bonds,
breaks in the earthing system and breaks in earth wire on the rise of
the earth potential (EPR) in a substation and at the transmission tower
bases using various models of an L6 tower. Different approaches
were adopted to examine the integrity of the earthing system and the
terminal towers. These effects were investigated to see the associated
difference in the EPR magnitudes with respect to a healthy system at
various locations. Comparisons of the computed EPR magnitudes
were then made between the healthy and unhealthy system to detect
any difference. The studies were conducted at power frequency for a
uniform soil with different soil resistivities. It was found that full
breaks in the double bond of the terminal towers increase the EPR
significantly at the fault location, while they reduce EPR at the
terminal tower bases. A fault on the isolated section of the grid can
result in EPR values up to 8 times of those on a healthy system at
higher soil resistivities, provided that the extended earthing system
stays connected to the grid.
Abstract: Interaction between mixing and crystallization is often
ignored despite the fact that it affects almost every aspect of the
operation including nucleation, growth, and maintenance of the
crystal slurry. This is especially pronounced in multiple impeller
systems where flow complexity is increased. By choosing proper
mixing parameters, what closely depends on the knowledge of the
hydrodynamics in a mixing vessel, the process of batch cooling
crystallization may considerably be improved. The values that render
useful information when making this choice are mixing time and
power consumption. The predominant motivation for this work was
to investigate the extent to which radial dual impeller configuration
influences mixing time, power consumption and consequently the
values of metastable zone width and nucleation rate. In this research,
crystallization of borax was conducted in a 15 dm3 baffled batch
cooling crystallizer with an aspect ratio (H/T) of 1.3. Mixing was
performed using two straight blade turbines (4-SBT) mounted on the
same shaft that generated radial fluid flow. Experiments were
conducted at different values of N/NJS ratio (impeller speed/
minimum impeller speed for complete suspension), D/T ratio
(impeller diameter/crystallizer diameter), c/D ratio (lower impeller
off-bottom clearance/impeller diameter), and s/D ratio (spacing
between impellers/impeller diameter). Mother liquor was saturated at
30°C and was cooled at the rate of 6°C/h. Its concentration was
monitored in line by Na-ion selective electrode. From the values of
supersaturation that was monitored continuously over process time, it
was possible to determine the metastable zone width and
subsequently the nucleation rate using the Mersmann’s nucleation
criterion. For all applied dual impeller configurations, the mixing
time was determined by potentiometric method using a pulse
technique, while the power consumption was determined using a
torque meter produced by Himmelstein & Co. Results obtained in
this investigation show that dual impeller configuration significantly
influences the values of mixing time, power consumption as well as
the metastable zone width and nucleation rate. A special attention
should be addressed to the impeller spacing considering the flow
interaction that could be more or less pronounced depending on the
spacing value.
Abstract: High double excitation of two-electron atoms has been
investigated using hyperpherical coordinates within a modified
adiabatic expansion technique. This modification creates a novel
fictitious force leading to a spontaneous exchange symmetry breaking
at high double excitation. The Pauli principle must therefore be
regarded as approximation valid only at low excitation energy.
Threshold electron scattering from high Rydberg states shows an
unexpected time reversal symmetry breaking. At threshold for double
escape we discover a broad (few eV) Cooper pair.
Abstract: This paper investigates the application of metallic
coatings on high fiber volume fraction carbon/epoxy polymer matrix
composites. For the grip of the metallic layer, a method of modifying
the surface of the composite by introducing a mixture of copper and
steel powder (filler powders) which can reduce the impact of thermal
spray particles. The powder was introduced to the surface at the time
of the forming. Arc spray was used to project the zinc coating layer.
The substrate was grit blasted to avoid poor adherence. The porosity, microstructure, and morphology of layers are
characterized by optical microscopy, SEM and image analysis. The
samples were studied also in terms of hardness and erosion resistance.
This investigation did not reveal any visible evidence damage to the
substrates. The hardness of zinc layer was about 25.94 MPa and the
porosity was around (∼6.70%). The erosion test showed that the zinc
coating improves the resistance to erosion. Based on the results
obtained, we can conclude that thermal spraying allows the production
of protective coating on PMC. Zinc coating has been identified as a
compatible material with the substrate. The filler powders layer
protects the substrate from the impact of hot particles and allows
avoiding the rupture of brittle carbon fibers.