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: The Hall Coefficient (HC) and the Magnetoresistance (MR) have been studied in two-dimensional systems. The HC and the MR in Rectangular Quantum Wire (RQW) subjected to a crossed DC electric field and magnetic field in the presence of a Strong Electromagnetic Wave (EMW) characterized by electric field are studied in this work. Using the quantum kinetic equation for electrons interacting with optical phonons, we obtain the analytic expressions for the HC and the MR with a dependence on magnetic field, EMW frequency, temperatures of systems and the length characteristic parameters of RQW. These expressions are different from those obtained for bulk semiconductors and cylindrical quantum wires. The analytical results are applied to GaAs/GaAs/Al. For this material, MR depends on the ratio of the EMW frequency to the cyclotron frequency. Indeed, MR reaches a minimum at the ratio 5/4, and when this ratio increases, it tends towards a saturation value. The HC can take negative or positive values. Each curve has one maximum and one minimum. When magnetic field increases, the HC is negative, achieves a minimum value and then increases suddenly to a maximum with a positive value. This phenomenon differs from the one observed in cylindrical quantum wire, which does not have maximum and minimum values.
Abstract: Anaerobic digestion is a well-known technique for
sustainable energy recovery from sewage sludge. However, sewage
sludge digestion is restricted due to certain factors. Pre-treatment
methods have been established in various publications as a promising
technique to improve the digestibility of the sewage sludge and to
enhance the biogas generated which can be used for energy recovery.
In this study, continuous flow microwave (MW) pre-treatment with
different intensities were compared by using 5 L semi-continuous
digesters at a hydraulic retention time of 27 days. We focused on the
effects of MW at different intensities on the sludge solubilization,
sludge digestibility, and biogas production of the untreated and MW
pre-treated sludge. The MW pre-treatment demonstrated an increase
in the ratio of soluble chemical oxygen demand to total chemical
oxygen demand (sCOD/tCOD) and volatile fatty acid (VFA)
concentration. Besides that, the total volatile solid (TVS) removal
efficiency and tCOD removal efficiency also increased during the
digestion of the MW pre-treated sewage sludge compared to the
untreated sewage sludge. Furthermore, the biogas yield also
subsequently increases due to the pre-treatment effect. A higher MW
power level and irradiation time generally enhanced the biogas
generation which has potential for sustainable energy recovery from
sewage treatment plant. However, the net energy balance tabulation
shows that the MW pre-treatment leads to negative net energy production.
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: Cancer is still one of the serious diseases threatening
the lives of human beings. How to have an early diagnosis and
effective treatment for tumors is a very important issue. The animal
carcinoma model can provide a simulation tool for the studies of
pathogenesis, biological characteristics, and therapeutic effects.
Recently, drug delivery systems have been rapidly developed to
effectively improve the therapeutic effects. Liposome plays an
increasingly important role in clinical diagnosis and therapy for
delivering a pharmaceutic or contrast agent to the targeted sites.
Liposome can be absorbed and excreted by the human body, and is
well known that no harm to the human body. This study aimed to
compare the therapeutic effects between encapsulated (doxorubicin
liposomal, Lipodox) and un-encapsulated (doxorubicin, Dox)
anti-tumor drugs using magnetic resonance imaging (MRI).
Twenty-four New Zealand rabbits implanted with VX2 carcinoma at
left thighs were classified into three groups: control group (untreated),
Dox-treated group, and LipoDox-treated group, 8 rabbits for each
group. MRI scans were performed three days after tumor implantation.
A 1.5T GE Signa HDxt whole body MRI scanner with a high
resolution knee coil was used in this study. After a 3-plane localizer
scan was performed, three-dimensional (3D) fast spin echo (FSE)
T2-weighted Images (T2WI) was used for tumor volumetric
quantification. Afterwards, two-dimensional (2D) spoiled gradient
recalled echo (SPGR) dynamic contrast-enhanced (DCE) MRI was
used for tumor perfusion evaluation. DCE-MRI was designed to
acquire four baseline images, followed by contrast agent Gd-DOTA
injection through the ear vein of rabbit. A series of 32 images were
acquired to observe the signals change over time in the tumor and
muscle. The MRI scanning was scheduled on a weekly basis for a
period of four weeks to observe the tumor progression longitudinally.
The Dox and LipoDox treatments were prescribed 3 times in the first
week immediately after the first MRI scan; i.e. 3 days after VX2 tumor
implantation. ImageJ was used to quantitate tumor volume and time
course signal enhancement on DCE images. The changes of tumor size
showed that the growth of VX2 tumors was effectively inhibited for
both LipoDox-treated and Dox-treated groups. Furthermore, the tumor
volume of LipoDox-treated group was significantly lower than that of
Dox-treated group, which implies that LipoDox has better therapeutic effect than Dox. The signal intensity of LipoDox-treated group is
significantly lower than that of the other two groups, which implies
that targeted therapeutic drug remained in the tumor tissue. This study
provides a radiation-free and non-invasive MRI method for
therapeutic monitoring of targeted liposome on an animal tumor
model.
Abstract: An early diagnosis of bone metastasis is very
important for making a right decision on a subsequent therapy. One
of the most important steps to be taken initially, for developing a new
radiopharmaceutical is the measurement of organ radiation exposure
dose. In this study, the dosimetric studies of a novel agent for
SPECT-imaging of the bone metastasis, 111In-(4-
{[(bis(phosphonomethyl))carbamoyl]methyl}7,10bis(carboxymethyl)
-1,4,7,10-tetraazacyclododec-1-yl) acetic acid (111In-BPAMD)
complex, have been carried out to estimate the dose in human organs
based on the data derived from mice. The radiolabeled complex was
prepared with high radiochemical purity in the optimal conditions.
Biodistribution studies of the complex was investigated in the male
Syrian mice at the selected times after injection (2, 4, 24 and 48 h).
The human absorbed dose estimation of the complex was made based
on data derived from the mice by the radiation absorbed dose
assessment resource (RADAR) method. 111In-BPAMD complex was prepared with high radiochemical
purity >95% (ITLC) and specific activities of 2.85 TBq/mmol. Total
body effective absorbed dose for 111In-BPAMD was 0.205
mSv/MBq. This value is comparable to the other 111In clinically used
complexes. The results show that the dose with respect to the critical
organs is satisfactory within the acceptable range for diagnostic
nuclear medicine procedures. Generally, 111In-BPAMD has
interesting characteristics and it can be considered as a viable agent
for SPECT-imaging of the bone metastasis in the near future.
Abstract: Abstract—[Tris (1,10-phenanthroline) lanthanum(III)]
trithiocyanate is a new compound that has shown high ability for
stopping the synthesis of DNA and also acting as a photosensitizer.
Nowadays, the radiation dose assessment resource (RADAR) method
is known as the most common method for absorbed dose calculation.
177Lu was produced by (n, gamma) reaction in a research reactor.
177Lu-PL3 was prepared in the optimized condition. The
radiochemical yield was checked by ITLC method. The
biodistribution of the complex was investigated by intravenously
injection to wild-type rats via their tail veins. In this study, the
absorbed dose of 177Lu-PL3 to human organs was estimated by
RADAR method. 177Lu was prepared with a specific activity of 2.6-3
GBq.mg-1 and radionuclide purity of 99.98 %. Final preparation of
the radiolabelled complex showed high radiochemical purity of >
99%. The results show that liver and spleen have received the highest
absorbed dose of 1.051 and 0.441 mSv/MBq, respectively. The
absorbed dose values for these two dose-limiting tissues suggest
more biological studies special in tumor-bearing animals.
Abstract: The measurement of organ radiation exposure dose is
one of the most important steps to be taken initially, for developing a
new radiopharmaceutical. In this study, the dosimetric studies of a
novel agent for SPECT-imaging of the bone metastasis, 111In-
1,4,7,10-tetraazacyclododecane-1,4,7,10 tetraethylene phosphonic
acid (111In-DOTMP) complex, have been carried out to estimate the
dose in human organs based on the data derived from rats. The
radiolabeled complex was prepared with high radiochemical purity in
the optimal conditions. Biodistribution studies of the complex was
investigated in the male Syrian rats at selected times after injection
(2, 4, 24 and 48 h). The human absorbed dose estimation of the
complex was made based on data derived from the rats by the
radiation absorbed dose assessment resource (RADAR) method.
111In-DOTMP complex was prepared with high radiochemical purity
of >99% (ITLC). Total body effective absorbed dose for 111In-
DOTMP was 0.061 mSv/MBq. This value is comparable to the other
111In clinically used complexes. The results show that the dose with
respect to the critical organs is satisfactory within the acceptable
range for diagnostic nuclear medicine procedures. Generally, 111In-
DOTMP has interesting characteristics and can be considered as a
viable agent for SPECT-imaging of the bone metastasis in the near
future.
Abstract: Fresh water is one of the resources which is getting
depleted day by day. A wise method to address this issue is by the
application of renewable energy-sun irradiation and by means of
decentralized, cheap, energetically self-sufficient, robust and simple
to operate plants, distillates can be obtained from sea, river or even
sewage. Solar desalination is a technique used to desalinate water
using solar energy. The present work deals with the comprehensive
design and simulation of solar tracking system using LabVIEW,
temperature and mass flow rate control of the solar desalination plant
using LabVIEW and also analysis of single phase inverter circuit
with LC filters for solar pumping system in MATLAB. The main
objective of this work is to improve the performance of solar
desalination system using automatic tracking system, output control
using temperature and mass flow rate control system and also to
reduce the harmonic distortion in the solar pumping system by means
of LC filters. The simulation of single phase inverter was carried out
using MATLAB and the output waveforms were analyzed.
Simulations were performed for optimum output temperature control,
which in turn controls the mass flow rate of water in the thermal
collectors. Solar tracking system was accomplished using LABVIEW
and was tested successfully. The thermal collectors are tracked in
accordance with the sun’s irradiance levels, thereby increasing the
efficiency of the thermal collectors.
Abstract: The development of composite materials and the
related design and manufacturing technologies is one of the most
important advances in the history of materials. Composites are
multifunctional materials having unprecedented mechanical and
physical properties that can be tailored to meet the requirements of a
particular application. Some composites also exhibit great resistance
to high-temperature corrosion, oxidation, and wear. Polymers are
widely used indoors and outdoors, therefore they are exposed to a
chemical environment which may include atmospheric oxygen, acidic
fumes, acidic rain, moisture heat and thermal shock, ultra-violet light,
high energy radiation, etc. Different polymers are affected differently
by these factors even though the amorphous polymers are more
sensitive. Ageing is also important and it is defined as the process of
deterioration of engineering materials resulting from the combined
effects of atmospheric radiation, heat, oxygen, water, microorganisms
and other atmospheric factors.
Abstract: The reheating furnace is used to reheat the steel slabs
before the hot-rolling process. The supported system includes the
stationary/moving beams, and the skid buttons which block some
thermal radiation transmitted to the bottom of the slabs. Therefore, it is
important to analyze the steel slab temperature distribution during the
heating period. A three-dimensional mathematical transient heat
transfer model for the prediction of temperature distribution within the
slab has been developed. The effects of different skid button height
(H=60mm, 90mm, and 120mm) and different gap distance between
two slabs (S=50mm, 75mm, and 100mm) on the slab skid mark
formation and temperature profiles are investigated. Comparison with
the in-situ experimental data from Steel Company in Taiwan shows
that the present heat transfer model works well for the prediction of
thermal behavior of the slab in the reheating furnace. It is found that
the skid mark severity decreases with an increase in the skid button
height. The effect of gap distance is important only for the slab edge
planes, while it is insignificant for the slab central planes.
Abstract: Radiative heat transfer in participating medium was
carried out using the finite volume method. The radiative transfer
equations are formulated for absorbing and anisotropically scattering
and emitting medium. The solution strategy is discussed and the
conditions for computational stability are conferred. The equations
have been solved for transient radiative medium and transient
radiation incorporated with transient conduction. Results have been
obtained for irradiation and corresponding heat fluxes for both the
cases. The solutions can be used to conclude incident energy and
surface heat flux. Transient solutions were obtained for a slab of heat
conducting in slab and by thermal radiation. The effect of heat
conduction during the transient phase is to partially equalize the
internal temperature distribution. The solution procedure provides
accurate temperature distributions in these regions. A finite volume
procedure with variable space and time increments is used to solve
the transient radiation equation. The medium in the enclosure
absorbs, emits, and anisotropically scatters radiative energy. The
incident radiations and the radiative heat fluxes are presented in
graphical forms. The phase function anisotropy plays a significant
role in the radiation heat transfer when the boundary condition is
non-symmetric.
Abstract: The ventilated façade has great advantages when
compared to traditional façades as it reduces the air conditioning
thermal loads due to the stack effect induced by solar radiation in the
air chamber. Optimizing energy consumption by using a ventilated
façade can be used not only in newly built buildings but also it can be
implemented in existing buildings, opening the field of
implementation to energy building retrofitting works. In this sense, the following three prototypes of façade where
designed, built and further analyzed in this research: non-ventilated
façade (NVF); slightly ventilated façade (SLVF) and strongly
ventilated façade (STVF). The construction characteristics of the
three facades are based on the Spanish regulation of building
construction “Technical Building Code”. The façades have been
monitored by type-k thermocouples in a representative day of the
summer season in Madrid (Spain). Moreover, an analysis of variance
(ANOVA) with repeated measures, studying the thermal lag in the
ventilated and no-ventilated façades has been designed. Results show that STVF façade presents higher levels of thermal
inertia as the thermal lag reduces up to 17% (daily mean) compared
to the non-ventilated façade. In addition, the statistical analysis
proves that an increase of the ventilation holes size in STVF façades
can improve the thermal lag significantly (p >0.05) when compared
to the SLVF façade.
Abstract: This paper discusses micrometeorological aspects of the urban climate in three cities in Western São Paulo State: Presidente Prudente, Assis and Iepê. Particular attention is paid to the method used to estimate the components of the energy balance at the surface. Estimates of convective fluxes showed that the Bowen ratio was an indicator of the local climate and that its magnitude varied between 0.3 and 0.7. Maximum values for the Bowen ratio occurred earlier in Iepê (11:00 am) than in Presidente Prudente (4:00 pm). The results indicate that the Bowen ratio is modulated by the radiation balance at the surface and by different clusters of vegetation.
Abstract: One of the most important challenging factors in
medical images is nominated as noise. Image denoising refers to the
improvement of a digital medical image that has been infected by
Additive White Gaussian Noise (AWGN). The digital medical image
or video can be affected by different types of noises. They are
impulse noise, Poisson noise and AWGN. Computed tomography
(CT) images are subjects to low quality due to the noise. Quality of
CT images is dependent on absorbed dose to patients directly in such
a way that increase in absorbed radiation, consequently absorbed
dose to patients (ADP), enhances the CT images quality. In this
manner, noise reduction techniques on purpose of images quality
enhancement exposing no excess radiation to patients is one the
challenging problems for CT images processing. In this work, noise
reduction in CT images was performed using two different
directional 2 dimensional (2D) transformations; i.e., Curvelet and
Contourlet and Discrete Wavelet Transform (DWT) thresholding
methods of BayesShrink and AdaptShrink, compared to each other
and we proposed a new threshold in wavelet domain for not only
noise reduction but also edge retaining, consequently the proposed
method retains the modified coefficients significantly that result good
visual quality. Data evaluations were accomplished by using two
criterions; namely, peak signal to noise ratio (PSNR) and Structure
similarity (Ssim).
Abstract: In most existing buildings in hot climate, cooling
loads lead to high primary energy consumption and consequently
high CO2 emissions. These can be substantially decreased with
integrated renewable energy systems. Kuwait is characterized by its
dry hot long summer and short warm winter. Kuwait receives annual
total radiation more than 5280 MJ/m2 with approximately 3347 h of
sunshine. Solar energy systems consist of PV modules and parabolic
trough collectors are considered to satisfy electricity consumption,
domestic water heating, and cooling loads of an existing building.
This paper presents the results of an extensive program of energy
conservation and energy generation using integrated photovoltaic
(PV) modules and Parabolic Trough Collectors (PTC). The program
conducted on an existing institutional building intending to convert it
into a Net-Zero Energy Building (NZEB) or near net Zero Energy
Building (nNZEB). The program consists of two phases; the first
phase is concerned with energy auditing and energy conservation
measures at minimum cost and the second phase considers the
installation of photovoltaic modules and parabolic trough collectors.
The 2-storey building under consideration is the Applied Sciences
Department at the College of Technological Studies, Kuwait. Single
effect lithium bromide water absorption chillers are implemented to
provide air conditioning load to the building. A numerical model is
developed to evaluate the performance of parabolic trough collectors
in Kuwait climate. Transient simulation program (TRNSYS) is
adapted to simulate the performance of different solar system
components. In addition, a numerical model is developed to assess
the environmental impacts of building integrated renewable energy
systems. Results indicate that efficient energy conservation can play
an important role in converting the existing buildings into NZEBs as
it saves a significant portion of annual energy consumption of the
building. The first phase results in an energy conservation of about
28% of the building consumption. In the second phase, the integrated
PV completely covers the lighting and equipment loads of the
building. On the other hand, parabolic trough collectors of optimum
area of 765 m2 can satisfy a significant portion of the cooling load,
i.e about73% of the total building cooling load. The annual avoided
CO2 emission is evaluated at the optimum conditions to assess the
environmental impacts of renewable energy systems. The total annual
avoided CO2 emission is about 680 metric ton/year which confirms
the environmental impacts of these systems in Kuwait.
Abstract: In this paper, we study the optical nonlinearities of
Silver sulfide (Ag2S) nanostructures dispersed in the Dimethyl
sulfoxide (DMSO) under exposure to 532 nm, 15 nanosecond (ns)
pulsed laser irradiation. Ultraviolet–visible absorption spectrometry
(UV-Vis), X-ray diffraction (XRD), and transmission electron
microscopy (TEM) are used to characterize the obtained nanocrystal
samples. The band gap energy of colloid is determined by analyzing
the UV–Vis absorption spectra of the Ag2S NPs using the band
theory of semiconductors. Z-scan technique is used to characterize
the optical nonlinear properties of the Ag2S nanoparticles (NPs).
Large enhancement of two photon absorption effect is observed with
increase in concentration of the Ag2S nanoparticles using open Zscan
measurements in the ns laser regime. The values of the nonlinear
absorption coefficients are determined based on the local nonlinear
responses including two photon absorption. The observed aperture
dependence of the Ag2S NP limiting performance indicates that the
nonlinear scattering plays an important role in the limiting action of
the sample. The concentration dependence of the optical liming is
also investigated. Our results demonstrate that the optical limiting
threshold decreases with increasing the silver sulfide NPs in DMSO.
Abstract: A multilayer passive shield composed of low-activity
lead (Pb), copper (Cu), tin (Sn) and iron (Fe) was designed and
manufactured for a coaxial HPGe detector placed at a surface
laboratory for reducing background radiation and radiation dose to
the personnel. The performance of the shield was evaluated and
efficiency curves of the detector were plotted by using of various
standard sources in different distances. Monte Carlo simulations and
a set of TLD chips were used for dose estimation in two distances of
20 and 40 cm. The results show that the shield reduced background
spectrum and the personnel dose more than 95%.
Abstract: It is an indispensible strategy to adopt greenery
approach on architectural bases so as to improve ecological habitats,
decrease heat-island effect, purify air quality, and relieve surface
runoff as well as noise pollution, all of which are done in an attempt to
achieve sustainable environment. How we can do with plant design to
attain the best visual quality and ideal carbon dioxide fixation depends
on whether or not we can appropriately make use of greenery
according to the nature of architectural bases. To achieve the goal, it is
a need that architects and landscape architects should be provided with
sufficient local references. Current greenery studies focus mainly on
the heat-island effect of urban with large scale. Most of the architects
still rely on people with years of expertise regarding the adoption and
disposition of plantation in connection with microclimate scale.
Therefore, environmental design, which integrates science and
aesthetics, requires fundamental research on landscape environment
technology divided from building environment technology. By doing
so, we can create mutual benefits between green building and the
environment. This issue is extremely important for the greening design
of the bases of green buildings in cities and various open spaces. The
purpose of this study is to establish plant selection and allocation
strategies under different building sunshade levels. Initially, with the
shading of sunshine on the greening bases as the starting point, the
effects of the shades produced by different building types on the
greening strategies were analyzed. Then, by measuring the PAR
(photosynthetic active radiation), the relative DLI (daily light integral)
was calculated, while the DLI Map was established in order to
evaluate the effects of the building shading on the established
environmental greening, thereby serving as a reference for plant
selection and allocation. The discussion results were to be applied in
the evaluation of environment greening of greening buildings and
establish the “right plant, right place” design strategy of multi-level
ecological greening for application in urban design and landscape
design development, as well as the greening criteria to feedback to the
eco-city greening buildings.
Abstract: As a by-product of the biodiesel industries, glycerol
has been vastly generated which surpasses the market demand. It is
imperative to develop an efficient glycerol valorization processes in
minimizing the net energy requirement and intensifying the biodiesel
production. In this study, base-catalyzed transesterification of
glycerol with dimethyl carbonate using microwave irradiation as
heating method to produce glycerol carbonate was conducted by
varying grades of glycerol, i.e. 70%, 86% and 99% purity, that is
obtained from biodiesel plant. Metal oxide catalysts were used with
varying operating parameters including reaction time, DMC/glycerol
molar ratio, catalyst weight %, temperature and stirring speed. From
the study on the effect of different operating parameters it was found
that the type of catalyst used has the most significant effect on the
transesterification reaction. Amidst the metal oxide catalysts
examined, CaO gave the best performance. This study indicates the
feasibility of producing glycerol carbonate using different grade of
glycerol in both conventional thermal activation and microwave
irradiation with CaO as catalyst. Microwave assisted
transesterification (MAT) of glycerol into glycerol carbonate has
demonstrated itself as an energy efficient route by achieving 94.2%
yield of GC at 65°C, 5 minutes reaction time, 1 wt% CaO and
DMC/glycerol molar ratio of 2. The advantages of MAT
transesterification route has made the direct utilization of bioglycerol
from biodiesel production without the need of purification. This has
marked a more economical and less-energy intensive glycerol
carbonate synthesis route.