Abstract: In this work, we incorporated a quartic bond potential
into a coarse-grained bead-spring model to study lubricant adsorption
on a solid surface as well as depletion instability. The surface tension
density and the number density profiles were examined to verify the
solid-liquid and liquid-vapor interfaces during heat treatment. It was
found that both the liquid-vapor interfacial thickness and the
solid-vapor separation increase with the temperatureT* when T*is
below the phase transition temperature Tc
*. At high temperatures
(T*>Tc
*), the solid-vapor separation decreases gradually as the
temperature increases. In addition, we evaluated the lubricant weight
and bond loss profiles at different temperatures. It was observed that
the lubricant desorption is favored over decomposition and is the main
cause of the lubricant failure at the head disk interface in our
simulations.
Abstract: Monitoring lightning electromagnetic pulses (sferics) and other terrestrial as well as extraterrestrial transient radiation signals is of considerable interest for practical and theoretical purposes in astro- and geophysics as well as meteorology. Managing a continuous flow of data, automation of the analysis and classification process is important. Features based on a combination of wavelet and statistical methods proved efficient for this task and serve as input into a radial basis function network that is trained to discriminate transient shapes from pulse like to wave like. We concentrate on signals in the Very Low Frequency (VLF, 3 -30 kHz) range in this paper, but the developed methods are independent of this specific choice.
Abstract: F-actin fibrils are the cytoskeleton of osteocytes. They react in a dynamic manner to mechanical loading, and strength and
reposition their efforts to reinforce the cells structure. We hypothesize that f-actin is temporarly disrupted after loading and repolymerizes
in a new orientation to oppose the applied load. In vitro studies are conducted to determine f-actin disruption after varying mechanical stimulus parameters that are known to affect bone
formation. Results indicate that the f-actin cytoskeleton is disrupted in vitro as a function of applied mechanical stimulus parameters and
that the f-actin bundles reassemble after loading induced disruption
within 3 minutes after cessation of loading. The disruption of the factin
cytoskeleton depends on the magnitude of stretch, the numbers
of loading cycles, frequency, the insertion of rest between loading
cycles and extracellular calcium. In vivo studies also demonstrate
disruption of the f-actin cytoskeleton in cells embedded in the bone
matrix immediately after mechanical loading. These studies suggest
that adaptation of the f-actin fiber bundles of the cytoskeleton in
response to applied loads occurs by disruption and subsequent repolymerization.
Abstract: A self-evolution algorithm for optimizing neural networks using a combination of PSO and JPSO is proposed. The algorithm optimizes both the network topology and parameters simultaneously with the aim of achieving desired accuracy with less complicated networks. The performance of the proposed approach is compared with conventional back-propagation networks using several synthetic functions, with better results in the case of the former. The proposed algorithm is also implemented on slope stability problem to estimate the critical factor of safety. Based on the results obtained, the proposed self evolving network produced a better estimate of critical safety factor in comparison to conventional BPN network.
Abstract: Landscape connectivity combines a description of the
physical structure of the landscape with special species- response to
that structure, which forms the theoretical background of applying
landscape connectivity principles in the practices of landscape
planning and design. In this study, a residential development project in
the southern United States was used to explore the meaning of
landscape connectivity and its application in town planning. The vast
rural landscape in the southern United States is conspicuously
characterized by the hedgerow trees or groves. The patchwork
landscape of fields surrounded by high hedgerows is a traditional and
familiar feature of the American countryside. Hedgerows are in effect
linear strips of trees, groves, or woodlands, which are often critical
habitats for wildlife and important for the visual quality of the
landscape. Based on geographic information system (GIS) and
statistical analysis (FRAGSTAT), this study attempts to quantify the
landscape connectivity characterized by hedgerows in south Alabama
where substantial areas of authentic hedgerow landscape are being
urbanized due to the ever expanding real estate industry and high
demand for new residential development. The results of this study
shed lights on how to balance the needs of new urban development and
biodiversity conservation by maintaining a higher level of landscape
connectivity, thus will inform the design intervention.
Abstract: A suspension bridge is the most suitable type of structure for a long-span bridge due to rational use of structural materials. Increased deformability, which is conditioned by appearance of the elastic and kinematic displacements, is the major disadvantage of suspension bridges. The problem of increased kinematic displacements under the action of non-symmetrical load can be solved by prestressing. The prestressed suspension bridge with the span of 200 m was considered as an object of investigations. The cable truss with the cross web was considered as the main load carrying structure of the prestressed suspension bridge. The considered cable truss was optimized by 47 variable factors using Genetic algorithm and FEM program ANSYS. It was stated, that the maximum total displacements are reduced up to 29.9% by using of the cable truss with the rational characteristics instead of the single cable in the case of the worst situated load.
Abstract: This paper deals with a novel approach of power
transformers diagnostics. This approach identifies the exact location
and the range of a fault in the transformer and helps to reduce
operation costs related to handling of the faulty transformer, its
disassembly and repair. The advantage of the approach is a
possibility to simulate healthy transformer and also all faults, which
can occur in transformer during its operation without its
disassembling, which is very expensive in practice. The approach is
based on creating frequency dependent impedance of the transformer
by sweep frequency response analysis measurements and by 3D FE
parametrical modeling of the fault in the transformer. The parameters
of the 3D FE model are the position and the range of the axial short
circuit. Then, by comparing the frequency dependent impedances of
the parametrical models with the measured ones, the location and the
range of the fault is identified. The approach was tested on a real
transformer and showed high coincidence between the real fault and
the simulated one.
Abstract: Engineered nanoparticles’ usage rapidly increased in
various applications in the last decade due to their unusual properties.
However, there is an ever increasing concern to understand their
toxicological effect in human health. Particularly, metal and metal
oxide nanoparticles have been used in various sectors including
biomedical, food and agriculture. But their impact on human health is
yet to be fully understood. In this present investigation, we assessed
the toxic effect of engineered nanoparticles (ENPs) including Ag,
MgO and Co3O4 nanoparticles (NPs) on human mesenchymal stem
cells (hMSC) adopting cell viability and cellular morphological
changes as tools The results suggested that silver NPs are more toxic
than MgO and Co3O4NPs. The ENPs induced cytotoxicity and
nuclear morphological changes in hMSC depending on dose. The cell
viability decreases with increase in concentration of ENPs. The
cellular morphology studies revealed that ENPs damaged the cells.
These preliminary findings have implications for the use of these
nanoparticles in food industry with systematic regulations.
Abstract: In this paper, a two factor scheme is proposed to
generate cryptographic keys directly from biometric data, which
unlike passwords, are strongly bound to the user. Hash value of the
reference iris code is used as a cryptographic key and its length
depends only on the hash function, being independent of any other
parameter. The entropy of such keys is 94 bits, which is much higher
than any other comparable system. The most important and distinct
feature of this scheme is that it regenerates the reference iris code by
providing a genuine iris sample and the correct user password. Since
iris codes obtained from two images of the same eye are not exactly
the same, error correcting codes (Hadamard code and Reed-Solomon
code) are used to deal with the variability. The scheme proposed here
can be used to provide keys for a cryptographic system and/or for
user authentication. The performance of this system is evaluated on
two publicly available databases for iris biometrics namely CBS and
ICE databases. The operating point of the system (values of False
Acceptance Rate (FAR) and False Rejection Rate (FRR)) can be set
by properly selecting the error correction capacity (ts) of the Reed-
Solomon codes, e.g., on the ICE database, at ts = 15, FAR is 0.096%
and FRR is 0.76%.
Abstract: In contrast to existing methods which do not take into account multiconnectivity in a broad sense of this term, we develop mathematical models and highly effective combination (BIEM and FDM) numerical methods of calculation of stationary and quasi-stationary temperature field of a profile part of a blade with convective cooling (from the point of view of realization on PC). The theoretical substantiation of these methods is proved by appropriate theorems. For it, converging quadrature processes have been developed and the estimations of errors in the terms of A.Ziqmound continuity modules have been received. For visualization of profiles are used: the method of the least squares with automatic conjecture, device spline, smooth replenishment and neural nets. Boundary conditions of heat exchange are determined from the solution of the corresponding integral equations and empirical relationships. The reliability of designed methods is proved by calculation and experimental investigations heat and hydraulic characteristics of the gas turbine first stage nozzle blade.
Abstract: Until recently, energy security and climate change
were considered separate issues to be dealt with by policymakers.
The two issues are now converging, challenging the security and
climate communities to develop a better understanding of how to deal
with both issues simultaneously. Although Egypt is not a major
contributor to the world's total GHG emissions, it is particularly
vulnerable to the potential effects of global climate change such as
rising sea levels and changed patterns of rainfall in the Nile Basin.
Climate change is a major threat to sustainable growth and
development in Egypt, and the achievement of the Millennium
Development Goals. Egypt-s capacity to respond to the challenges of
climate instability will be expanded by improving overall resilience,
integrating climate change goals into sustainable development
strategies, increasing the use of modern energy systems with reduced
carbon intensity, and strengthening international initiatives. This
study seeks to establish a framework for considering the complex and
evolving links between energy security and climate change,
applicable to Egypt.
Abstract: This paper proposes a new algebraic scheme to design a PID controller for higher order linear time invariant continuous systems. Modified PSO (MPSO) based model order formulation techniques have applied to obtain the effective formulated second order system. A controller is tuned to meet the desired performance specification by using pole-zero cancellation method. Proposed PID controller is attached with both higher order system and formulated second order system. The closed loop response is observed for stabilization process and compared with general PSO based formulated second order system. The proposed method is illustrated through numerical example from literature.
Abstract: A co-generation system in automobile can improve
thermal efficiency of vehicle in some degree. The waste heat from the
engine exhaust and coolant is still attractive energy source that reaches
around 60% of the total energy converted from fuel. To maximize the
effectiveness of heat exchangers for recovering the waste heat, it is
vital to select the most suitable working fluid for the system, not to
mention that it is important to find the optimum design for the heat
exchangers. The design of heat exchanger is out of scoop of this study;
rather, the main focus has been on the right selection of working fluid
for the co-generation system. Simulation study was carried out to find
the most suitable working fluid that can allow the system to achieve
the optimum efficiency in terms of the heat recovery rate and thermal
efficiency.
Abstract: Cybercrime is now becoming a big challenge in Nigeria apart from the traditional crime. Inability to identify perpetrators is one of the reasons for the growing menace. This paper proposes a design for monitoring internet users’ activities in order to curbing cybercrime. It requires redefining the operations of Internet Service Providers (ISPs) which will now mandate users to be authenticated before accessing the internet. In implementing this work which can be adapted to a larger scale, a virtual router application is developed and configured to mimic a real router device. A sign-up portal is developed to allow users to register with the ISP. The portal asks for identification information which will include bio-data and government issued identification data like National Identity Card number, et cetera. A unique username and password are chosen by the user to enable access to the internet which will be used to reference him to an Internet Protocol Address (IP Address) of any system he uses on the internet and thereby associating him to any criminal act related to that IP address at that particular time. Questions such as “What happen when another user knows the password and uses it to commit crime?” and other pertinent issues are addressed.
Abstract: Electron multiplying charge coupled devices (EMCCDs) have revolutionized the world of low light imaging by introducing on-chip multiplication gain based on the impact ionization effect in the silicon. They combine the sub-electron readout noise with high frame rates. Signal-to-noise Ratio (SNR) is an important performance parameter for low-light-level imaging systems. This work investigates the SNR performance of an EMCCD operated in Non-inverted Mode (NIMO) and Inverted Mode (IMO). The theory of noise characteristics and operation modes is presented. The results show that the SNR of is determined by dark current and clock induced charge at high gain level. The optimum SNR performance is provided by an EMCCD operated in NIMO in short exposure and strong cooling applications. In contrast, an IMO EMCCD is preferable.
Abstract: To study the impact of the inter-module ventilation (IMV) on the space station, the Computational Fluid Dynamic (CFD) model under the influence of IMV, the mathematical model, boundary conditions and calculation method are established and determined to analyze the influence of IMV on cabin air flow characteristics and velocity distribution firstly; and then an integrated overall thermal mathematical model of the space station is used to consider the impact of IMV on thermal management. The results show that: the IMV has a significant influence on the cabin air flow, the flowrate of IMV within a certain range can effectively improve the air velocity distribution in cabin, if too much may lead to its deterioration; IMV can affect the heat deployment of the different modules in space station, thus affecting its thermal management, the use of IMV can effectively maintain the temperature levels of the different modules and help the space station to dissipate the waste heat.
Abstract: In April 2009, a new variant of Influenza A virus
subtype H1N1 emerged in Mexico and spread all over the world. The
influenza has three subtypes in human (H1N1, H1N2 and H3N2)
Types B and C influenza tend to be associated with local or regional
epidemics. Preliminary genetic characterization of the influenza
viruses has identified them as swine influenza A (H1N1) viruses.
Nucleotide sequence analysis of the Haemagglutinin (HA) and
Neuraminidase (NA) are similar to each other and the majority of
their genes of swine influenza viruses, two genes coding for the
neuraminidase (NA) and matrix (M) proteins are similar to
corresponding genes of swine influenza. Sequence similarity between
the 2009 A (H1N1) virus and its nearest relatives indicates that its
gene segments have been circulating undetected for an extended
period. Nucleic acid sequence Maximum Likelihood (MCL) and
DNA Empirical base frequencies, Phylogenetic relationship amongst
the HA genes of H1N1 virus isolated in Genbank having high
nucleotide sequence homology.
In this paper we used 16 HA nucleotide sequences from NCBI for
computing sequence relationships similarity of swine influenza A
virus using the following method MCL the result is 28%, 36.64% for
Optimal tree with the sum of branch length, 35.62% for Interior
branch phylogeny Neighber – Join Tree, 1.85% for the overall
transition/transversion, and 8.28% for Overall mean distance.
Abstract: Nowadays wireless technology plays an important
role in public and personal communication. However, the growth of
wireless networking has confused the traditional boundaries between
trusted and untrusted networks. Wireless networks are subject to a
variety of threats and attacks at present. An attacker has the ability to
listen to all network traffic which becoming a potential intrusion.
Intrusion of any kind may lead to a chaotic condition. In addition,
improperly configured access points also contribute the risk to
wireless network. To overcome this issue, a security solution that
includes an intrusion detection and prevention system need to be
implemented. In this paper, first the security drawbacks of wireless
network will be analyzed then investigate the characteristics and also
the limitations on current wireless intrusion detection and prevention
system. Finally, the requirement of next wireless intrusion prevention
system will be identified including some key issues which should be
focused on in the future to overcomes those limitations.
Abstract: The optimal bisection width of r-dimensional N×
· · ·× N grid is known to be Nr-1 when N is even, but when
N is odd, only approximate values are available. This paper
shows that the exact bisection width of grid is Nr
-1
N-1 when N is odd.
Abstract: Optimization of extraction of phenolic compounds
from Avicennia marina using response surface methodology was
carried out during the present study. Five levels, three factors
rotatable design (CCRD) was utilized to examine the optimum
combination of extraction variables based on the TPC of Avicennia
marina leaves. The best combination of response function was 78.41
°C, drying temperature; 26.18°C; extraction temperature and 36.53
minutes of extraction time. However, the procedure can be promptly
extended to the study of several others pharmaceutical processes like
purification of bioactive substances, drying of extracts and
development of the pharmaceutical dosage forms for the benefit of
consumers.