Abstract: Modern low earth orbit (LEO) satellites that require multi-mission flexibility are highly likely to be repositioned between different operational orbits. While executing this process the satellite may experience high levels of vibration and environmental hazards, exposing the deployed solar panel to dangerous stress levels, fatigue and space debris, hence it is desirable to retract the solar array before satellite repositioning to avoid damage or failure.
A novel concept of deployable/retractable hybrid solar array systemcomposed of both rigid and flexible solar panels arranged within a petal formation, aimed to provide a greater power to volume ratio while dramatically reducing mass and cost is proposed.
Abstract: Sandwich structure composites produced by epoxy
core and aluminium skin were developed as potential building
materials. Interface bonding between core and skin was controlled by
varying kenaf content. Five different weight percentage of kenaf
loading ranging from 10 wt% to 50 wt% were employed in the core
manufacturing in order to study the mechanical properties of the
sandwich composite. Properties of skin aluminium with epoxy were
found to be affected by drying time of the adhesive. Mechanical
behavior of manufactured sandwich composites in relation with
properties of constituent materials was studied. It was found that 30
wt% of kenaf loading contributed to increase the flexural strength and
flexural modulus up to 102 MPa and 32 GPa, respectively. Analysis
were done on the flatwise and edgewise compression test. For
flatwise test, it was found that 30 wt% of fiber loading could
withstand maximum force until 250 kN, with compressive strength
results at 96.94 MPa. However, at edgewise compression test, the
sandwich composite with same fiber loading only can withstand 31
kN of the maximum load with 62 MPa of compressive strength
results.
Abstract: The 6th version of Universal modeling method for
centrifugal compressor stage calculation is described. Identification
of the new mathematical model was made. As a result of
identification the uniform set of empirical coefficients is received.
The efficiency definition error is 0,86 % at a design point. The
efficiency definition error at five flow rate points (except a point of
the maximum flow rate) is 1,22 %. Several variants of the stage with
3D impellers designed by 6th version program and quasi threedimensional
calculation programs were compared by their gas
dynamic performances CFD (NUMECA FINE TURBO).
Performance comparison demonstrated general principles of design
validity and leads to some design recommendations.
Abstract: The present study was undertaken to investigate the
effect of aging parameters (time and temperature) on the mechanical
properties of Be-and/or Zr- treated Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys containing Be and/or Zr. Different aging
treatment were carried out for the as solution treated (SHT)
specimens (after quenching in warm water). The specimens were
aged at different conditions; Natural and artificial aging was carried
out at room temperature, 120C, 150C, 180C and 220C for different
periods of time. Duplex aging was performed for SHT conditions
(pre-aged at different time and temperature followed by high
temperature aging). Ultimate tensile strength, yield strength and %
elongation data results as a function of different aging parameters are
analysed. A statistical design of experiments (DOE) approach using
fractional factorial design is applied to acquire an understanding of
the effects of these variables and their interactions on the mechanical
properties of Be- and/or Zr- treated 7075 alloys. Mathematical
models are developed to relate the alloy mechanical properties with
the different aging parameters.
Abstract: This study concerned the dynamic behavior of the
wind turbine rotor. Before all we have studied the loads applied to the
rotor, which allows the knowledge their effect on the fatigue, also
studied the rotor with longitudinal crack in order to determine stress,
strain and displacement. Firstly we compared the first six modes
shapes between cracking and uncracking of HAWT rotor. Secondly
we show show evolution of first six natural frequencies with
longitudinal crack propagation. Finally we conclude that the residual
change in the natural frequencies can be used as in shaft crack
diagnosis predictive maintenance.
Abstract: Early detection of breast cancer saves many thousands
of lives each year via application of mammography and genetic
screening and many more lives could be saved if nurses are involved
in breast care screening practices. So, the aim of the study was to
identify nurse's role in early detection of breast cancer through
mammography and genetic screening and its impact on patient's
outcome. In order to achieve this aim, 400 women above 40 years,
asymptomatic were recruited for mammography and genetic
screening. In addition, 50 nurses and 6 technologists were involved in
the study. A descriptive analytical design was used. Five tools were
utilized: sociodemographic, mammographic examination and risk
factors, women's before, during and after mammography, items
relaying to technologists, and items related to nurses were also
obtained. The study finding revealed that 3% of women detected for
malignancy and 7.25% for fibroadenoma. Statistically significant
differences were found between mammography results and age,
family history, genetic screening, exposure to smoke, and using
contraceptive pills. Nurses have insufficient knowledge about
screening tests. Based on these findings the present study
recommended involvement of nurses in breast care which is very
important to in force population about screening practices.
Abstract: The aim of this study is to develop an anterior lumbar
interbody fusion (ALIF) PEEK cage suitable for Korean people. In this
study, CT images were obtained from Korean male (173cm, 71kg) and
3D Korean lumbar models were reconstructed based on the CT images
to investigate anatomical characteristics. Major design parameters of
anterior lumbar interbody fusion (ALIF) PEEK Cage were selected
using the morphological measurement information of the Korean
Lumbar models. Through finite element analysis and mechanical tests,
the developed ALIFPEEK Cage prototype was compared with the
Fidji Cage (Zimmer. Inc, USA) and it was found that the ALIF
prototype showed similar and/or superior mechanical performance
compared to the FidJi Cage. Also, clinical validation for the ALIF
PEEK Cage prototype was carried out to check predictable troubles in
surgical operations. Finally, it is considered that the convenience and
stability of the prototype was clinically verified.
Abstract: The Standard Penetration Test (SPT) is the most
common in situ test for soil investigations. On the other hand, the
Cone Penetration Test (CPT) is considered one of the best
investigation tools. Due to the fast and accurate results that can be
obtained it complaints the SPT in many applications like field
explorations, design parameters, and quality control assessments.
Many soil index and engineering properties have been correlated to
both of SPT and CPT. Various foundation design methods were
developed based on the outcome of these tests. Therefore it is vital to
correlate these tests to each other so that either one of the tests can be
used in the absence of the other, especially for preliminary evaluation
and design purposes.
The primary purpose of this study was to investigate the
relationships between the SPT and CPT for different type of sandy
soils in Florida. Data for this research were collected from number of
projects sponsored by the Florida Department of Transportation
(FDOT), six sites served as the subject of SPT-CPT correlations. The
correlations were established between the cone resistance (qc), sleeve
friction (fs) and the uncorrected SPT blow counts (N) for various
soils.
A positive linear relationship was found between qc, fs and N for
various sandy soils. In general, qc versus N showed higher
correlation coefficients than fs versus N. qc/N ratios were developed
for different soil types and compared to literature values, the results
of this research revealed higher ratios than literature values.
Abstract: The industrial process adds to engineering wood
products features absent in solid wood, with homogeneous structure
and reduced defects, improved physical and mechanical properties,
bio-deterioration, resistance and better dimensional stability,
improving quality and increasing the reliability of structures wood.
These features combined with using fast-growing trees, make them
environmentally ecological products, ensuring a strong consumer
market. The wood I-joists are manufactured by the industrial profiles
bonding flange and web, an important aspect of the production of
wooden I-beams is the adhesive joint that bonds the web to the
flange. Adhesives can effectively transfer and distribute stresses,
thereby increasing the strength and stiffness of the composite. The
objective of this study is to evaluate different resins in a shear strain
specimens with the aim of analyzing the most efficient resin and
possibility of using national products, reducing the manufacturing
cost. First was conducted a literature review, where established the
geometry and materials generally used, then established and analyzed
8 national resins and produced six specimens for each.
Abstract: An analysis is carried out to investigate the effect of
magnetic field and heat source on the steady boundary layer flow and
heat transfer of a Casson nanofluid over a vertical cylinder stretching
exponentially along its radial direction. Using a similarity
transformation, the governing mathematical equations, with the
boundary conditions are reduced to a system of coupled, non –linear
ordinary differential equations. The resulting system is solved
numerically by the fourth order Runge – Kutta scheme with shooting
technique. The influence of various physical parameters such as
Reynolds number, Prandtl number, magnetic field, Brownian motion
parameter, thermophoresis parameter, Lewis number and the natural
convection parameter are presented graphically and discussed for non
– dimensional velocity, temperature and nanoparticle volume
fraction. Numerical data for the skin – friction coefficient, local
Nusselt number and the local Sherwood number have been tabulated
for various parametric conditions. It is found that the local Nusselt
number is a decreasing function of Brownian motion parameter Nb
and the thermophoresis parameter Nt.
Abstract: Verification and Validation of Simulated Process
Model is the most important phase of the simulator life cycle.
Evaluation of simulated process models based on Verification and
Validation techniques checks the closeness of each component model
(in a simulated network) with the real system/process with respect to
dynamic behaviour under steady state and transient conditions. The
process of Verification and Validation helps in qualifying the process
simulator for the intended purpose whether it is for providing
comprehensive training or design verification. In general, model
verification is carried out by comparison of simulated component
characteristics with the original requirement to ensure that each step
in the model development process completely incorporates all the
design requirements. Validation testing is performed by comparing
the simulated process parameters to the actual plant process
parameters either in standalone mode or integrated mode.
A Full Scope Replica Operator Training Simulator for PFBR -
Prototype Fast Breeder Reactor has been developed at IGCAR,
Kalpakkam, INDIA named KALBR-SIM (Kalpakkam Breeder
Reactor Simulator) where in the main participants are
engineers/experts belonging to Modeling Team, Process Design and
Instrumentation & Control design team. This paper discusses about
the Verification and Validation process in general, the evaluation
procedure adopted for PFBR operator training Simulator, the
methodology followed for verifying the models, the reference
documents and standards used etc. It details out the importance of
internal validation by design experts, subsequent validation by
external agency consisting of experts from various fields, model
improvement by tuning based on expert’s comments, final
qualification of the simulator for the intended purpose and the
difficulties faced while co-coordinating various activities.
Abstract: This study is concerned with the optimization of
fermentation parameters for the hyper production of mannanase from
Fusarium oxysporum SS-25 employing two step statistical strategy
and kinetic characterization of crude enzyme preparation. The
Plackett-Burman design used to screen out the important factors in
the culture medium revealed 20% (w/w) wheat bran, 2% (w/w) each
of potato peels, soyabean meal and malt extract, 1% tryptone, 0.14%
NH4SO4, 0.2% KH2PO4, 0.0002% ZnSO4, 0.0005% FeSO4, 0.01%
MnSO4, 0.012% SDS, 0.03% NH4Cl, 0.1% NaNO3 in brewer’s spent
grain based medium with 50% moisture content, inoculated with
2.8×107 spores and incubated at 30oC for 6 days to be the main
parameters influencing the enzyme production. Of these factors, four
variables including soyabean meal, FeSO4, MnSO4 and NaNO3 were
chosen to study the interactive effects and their optimum levels in
central composite design of response surface methodology with the
final mannanase yield of 193 IU/gds. The kinetic characterization
revealed the crude enzyme to be active over broader temperature and
pH range. This could result in 26.6% reduction in kappa number with
4.93% higher tear index and 1% increase in brightness when used to
treat the wheat straw based kraft pulp. The hydrolytic potential of
enzyme was also demonstrated on both locust bean gum and guar
gum.
Abstract: This study attempts to elicit the perceptions and
attitudes of EFL learners of the Preparatory Year Program at KSU
towards dialogue journal writing as an EFL learning strategy. The
descriptive research design used incorporated both qualitative and
quantitative instruments to accomplish the objectives of the study. A
learners’ attitude questionnaire and follow-up interviewswith learners
from a randomly selected representative sample of the participants
were employed. The participants were 55 female Saudi university
students in the Preparatory Year Program at King Saud University.
The analysis of the results indicated that the PYP learners had highly
positive attitudes towards dialogue journal writing in their EFL
classes and positive perceptions of the benefits of the use of dialogue
journal writing as an EFL learning strategy. The results also revealed
that dialogue journals are considered an effective EFL learning
strategy since they fulfill various needs for both learners and
instructors. Interestingly, the analysis of the results also revealed that
Saudi university level students tend to write about personal topics in
their dialogue journals more than academic ones.
Abstract: Polysulfone (PSU) is a specialty engineering polymer
having various industrial applications. PSU is especially used in
waste water treatment membranes due to its good mechanical
properties, structural and chemical stability. But it is a hydrophobic
material and therefore its surface aim to pollute easily. In order to
resolve this problem and extend the properties of membrane, PSU
surface is rendered hydrophilic by addition of the sepiolite
nanofibers. Sepiolite is one of the natural clays, which is a hydrate
magnesium silicate fiber, also one of the well known layered clays of
the montmorillonites where has several unique channels and pores
within. It has also moisture durability, strength and low price.
Sepiolite channels give great capacity of absorption and good surface
properties. In this study, nanocomposites of commercial PSU and
Sepiolite were prepared by solvent mixing method. Different organic
solvents and their mixtures were used. Rheological characteristics of
PSU-Sepiolite solvent mixtures were analyzed, the solubility of
nanocomposite content in those mixtures were studied.
Abstract: The design and plantwide control of an integrated
plant where the endothermic 1,4-butanediol dehydrogenation and the
exothermic furfural hydrogenation is simultaneously performed in a
single reactor is studied. The reactions can be carried out in an
adiabatic reactor using small hydrogen excess and with reduced
parameter sensitivity. The plant is robust and flexible enough to
allow different production rates of γ-butyrolactone and 2-methyl
furan, keeping high product purities. Rigorous steady state and
dynamic simulations performed in AspenPlus and AspenDynamics to
support the conclusions.
Abstract: This work presents synthesis of α,ω-dithienyl
terminated poly(ethylene glycol) (PEGTh) capable for further chain
extension by either chemical or electrochemical polymeriztion.
PEGTh was characterized by FTIR and 1H-NMR. Further
copolymerization of PEGTh and pyrrole (Py) was performed by
chemical oxidative polymerization using ceric (IV) salt as an oxidant
(PPy-PEGTh). PEG without end group modification was used
directly to prepare copolymers with Py by Ce (IV) salt (PPy-PEG).
Block copolymers with mole ratio of pyrrole to PEGTh (PEG) 50:1
and 10:1 were synthesized. The electrical conductivities of
copolymers PPy-PEGTh and PPy-PEG were determined by four
point probe technique. Influence of the synthetic route and content of
the insulating segment on conductivity and yield of the copolymers
were investigated.
Abstract: The emerging Cognitive Radio is combo of both the
technologies i.e. Radio dynamics and software technology. It involve
wireless system with efficient coding, designing, and making them
artificial intelligent to take the decision according to the surrounding
environment and adopt themselves accordingly, so as to deliver the
best QoS. This is the breakthrough from fixed hardware and fixed
utilization of the spectrum. This software-defined approach of
research is centralized at user-definition and application driven
model, various software method are used for the optimization of the
wireless communication. This paper focused on the Spectrum
allocation technique using genetic algorithm GA to evolve radio,
represented by chromosomes. The chromosomes gene represents the
adjustable parameters in given radio and by using GA, evolving over
the generations, the optimized set of parameters are evolved, as per
the requirement of user and availability of the spectrum, in our
prototype the gene consist of 6 different parameters, and the best set
of parameters are evolved according to the application need and
availability of the spectrum holes and thus maintaining best QoS for
user, simultaneously maintaining licensed user rights. The analyzing
tool Matlab is used for the performance of the prototype.
Abstract: Bio-composites derived from plant fiber and/or bioderived
polymer, are likely more ecofriendly and demonstrate
competitive performance with petroleum based composites. In this
research, the bio phenol-formaldehyde (bio-PF) was used as a matrix
and oil palm empty fruit bunch fiber (EFB) as reinforcement. The
matrix was synthesized via liquefaction and condensation to enhance
the combination of phenol and formaldehyde, during the process.
Then, the bio-PF was mixed with different percentage of EFB (5%,
10%, 15% and 20%) and molded at 180oC. The samples that viewed
under scanning electron microscopy (SEM) showed an excellent
wettability and interaction between EFB and matrix. Samples of 10%
EFB gave the optimum properties of impact and hardness meanwhile
sample 15% of EFB gave the highest reading of flexural modulus
(MOE) and flexural strength (MOR). For thermal stability analysis, it
was found that the weight loss and the activation energy (Ea) of the
bio-composites samples were decreased as the filler content
increased.
Abstract: Eucalyptus species are well reputed for their
traditional use in Asia as well as in other parts of the world; therefore,
the present study was designed to investigate the antimicrobial and
antioxidant activities associated with essential oils from different
Eucalyptus species. Essential oils from the leaves of six Eucalyptus
species, including: Eucalyptus woodwardi, Eucalyptus stricklandii,
Eucalyptus salubris, Eucalyptus sargentii, Eucalyptus torquata and
Eucalyptus wandoo were separated by hydrodistillation and dried
over anhydrous sodium sulphate. DPPH, ferric reducing antioxidant
power, and hydroxyl radical scavenging activity assays were carried
out to evaluate the antioxidant potential of the oils. The results
indicate that examined oils exhibit substantial antioxidant activities
relative to ascorbic acid. Previously, these oils were evaluated for
their antimicrobial activities, against wide range of bacterial and
fungal strains, and they were shown to possess significant
antimicrobial activities. In this study, further investigation into the
growth kinetics of oil-treated microbial cultures was conducted. The
results clearly demonstrate that the microbial growth was markedly
inhibited when treated with sub-MIC concentrations of the oils.
Taken together, the results obtained indicate a high potential of the
examined essential oils as bioactive oils, for nutraceutical and
medical applications, possessing significant antioxidant and anti
microbial activities.
Abstract: Fast changing knowledge systems on the Internet can
be accessed more efficiently with the help of automatic document
summarization and updating techniques. The aim of multi-document
update summary generation is to construct a summary unfolding the
mainstream of data from a collection of documents based on the
hypothesis that the user has already read a set of previous documents.
In order to provide a lot of semantic information from the documents,
deeper linguistic or semantic analysis of the source documents were
used instead of relying only on document word frequencies to select
important concepts. In order to produce a responsive summary,
meaning oriented structural analysis is needed. To address this issue,
the proposed system presents a document summarization approach
based on sentence annotation with aspects, prepositions and named
entities. Semantic element extraction strategy is used to select
important concepts from documents which are used to generate
enhanced semantic summary.