Abstract: A three-dimensional numerical simulation of flow
through mini and microchannels with designed roughness is
conducted here. The effect of the roughness height (surface
roughness), geometry, Reynolds number on the friction factor, and
Nusselt number is investigated. The study is carried out by
employing CFD software, CFX. Our work focuses on a water flow
inside a circular mini-channel of 1 mm and microchannels of 500 and
100 m in diameter. The speed entry varies from 0.1 m/s to 20 m/s.
The general trend can be observed that bigger sizes of roughness
element lead to higher flow resistance. It is found that the friction
factor increases in a nonlinear fashion with the increase in obstruction
height. Particularly, the effect of roughness can no longer be ignored
at relative roughness height higher than 3%. A significant increase in
Poiseuille number is detected for all configurations considered. The
same observation can be done for Nusselt number. The transition
zone between laminar and turbulent flow depends on the channel
diameter.
Abstract: The goal of this paper is to specify factors influencing
the profitability of selected banks. Next, a model will be created to
help establish variables that have a demonstrable influence on the
development of the selected banks' profitability ratios. Czech banks
and their international parent companies were selected for analyzing
profitability. Banks categorized as large banks (according to the
Czech National Bank's system, which ranks banks according to
balance sheet total) were selected to represent the Czech banks. Two
ratios, the return on assets ratio (ROA) and the return on equity ratio
(ROE) are used to assess bank profitability. Six endogenous and four
external indicators were selected from among other factors that
influence bank profitability. The data analyzed were for 2001–2013.
First, correlation analysis, which was supposed to eliminate
correlated values, was conducted. A large number of correlated
values were established on the basis of this analysis. The strongly
correlated values were omitted. Despite this, the subsequent
regression analysis of profitability for the individual banks that were
selected did not confirm that the selected variables influenced their
profitability. The studied factors' influence on bank profitability was
demonstrated only for Ceskoslovenska Obchodni Banka and Société
Générale using regression analysis. For Československa Obchodni
Banka, it was demonstrated that inflation level and the amount of the
central bank's interest rate influenced the return on assets ratio and
that capital adequacy and market concentration influenced the return
on equity ratio for Société Générale.
Abstract: Privacy is sacred and would normally be expected and preserved by an individual. Online privacy is no longer about the right to be left alone, but also includes the right not to be monitored. However, with the revelations made by United States National Security Agency former employee Edward Snowden that the government is spying on internet communications, individuals’ privacy can no longer be expected. Therefore, this paper is intended to evaluate law related to privacy protection in the digital domain, who should govern it and whether invasion to a person’s privacy is a necessary justification to preserve national security.
Abstract: This paper introduces a signal monitoring program
developed with a view to helping electrical engineering students get
familiar with sensors with digital output. Because the output of digital
sensors cannot be simply monitored by a measuring instrument such as
an oscilloscope, students tend to have a hard time dealing with digital
sensors. The monitoring program runs on a PC and communicates with
an MCU that reads the output of digital sensors via an asynchronous
communication interface. Receiving the sensor data from the MCU,
the monitoring program shows time and/or frequency domain plots of
the data in real time. In addition, the monitoring program provides a
serial terminal that enables the user to exchange text information with
the MCU while the received data is plotted. The user can easily
observe the output of digital sensors and configure the digital sensors
in real time, which helps students who do not have enough experiences
with digital sensors. Though the monitoring program was programmed
in the Matlab programming language, it runs without the Matlab since
it was compiled as a standalone executable.
Abstract: Considering the challenges of short product life cycles
and growing variant diversity, cost minimization and manufacturing
flexibility increasingly gain importance to maintain a competitive
edge in today’s global and dynamic markets. In this context, an
aerodynamic part feeding system for high-speed industrial assembly
applications has been developed at the Institute of Production
Systems and Logistics (IFA), Leibniz Universitaet Hannover. The
aerodynamic part feeding system outperforms conventional systems
with respect to its process safety, reliability, and operating speed. In
this paper, a multi-objective optimisation of the aerodynamic feeding
system regarding the orientation rate, the feeding velocity, and the
required nozzle pressure is presented.
Abstract: Durian skin is a newly explores natural fibre
potentially reinforced polyolefin for diverse applications. In this
work, investigation on the effect of coupling agent, maleic anhydride
polypropylene (MAPP) on the mechanical, morphological, and
thermal properties of polypropylene (PP) reinforced with durian skin
fibre (DSF) was conducted. The presence of 30 wt% DSF
significantly reduced the tensile strength of PP-DSF composite.
Interestingly, even though the same trend goes to PP-DSF with the
presence of MAPP, the reduction is only about 4% relative to
unreinforced PP and 18% higher than PP-DSF without MAPP
(untreated composite or UTC). The used of MAPP in treated
composite (TC) also increased the tensile modulus, flexural
properties and degradation temperature. The enhanced mechanical
properties are consistent with good interfacial interaction as
evidenced under scanning electron microscopy.
Abstract: The modelling of physical phenomena, such as the
earth’s free oscillations, the vibration of strings, the interaction of
atomic particles, or the steady state flow in a bar give rise to Sturm-
Liouville (SL) eigenvalue problems. The boundary applications of
some systems like the convection-diffusion equation, electromagnetic
and heat transfer problems requires the combination of Dirichlet and
Neumann boundary conditions. Hence, the incorporation of Robin
boundary condition in the analyses of Sturm-Liouville problem. This
paper deals with the computation of the eigenvalues and
eigenfunction of generalized Sturm-Liouville problems with Robin
boundary condition using the finite element method. Numerical
solution of classical Sturm–Liouville problem is presented. The
results show an agreement with the exact solution. High results
precision is achieved with higher number of elements.
Abstract: In this study, the time-dependent behavior of damaged
reinforced concrete shear wall structures strengthened with composite
plates having variable fibers spacing was investigated to analyze their
seismic response. In the analytical formulation, the adherent and the
adhesive layers are all modeled as shear walls, using the mixed Finite
Element Method (FEM). The anisotropic damage model is adopted to
describe the damage extent of the Reinforced Concrete shear walls.
The phenomenon of creep and shrinkage of concrete has been
determined by Eurocode 2. Large earthquakes recorded in Algeria
(El-Asnam and Boumerdes) have been tested to demonstrate the
accuracy of the proposed method. Numerical results are obtained for non-uniform distributions of
carbon fibers in epoxy matrices. The effects of damage extent and the
delay mechanism creep and shrinkage of concrete are highlighted.
Prospects are being studied.
Abstract: Gastric Cancer (GC) has high morbidity and fatality
rate in various countries. It is still one of the most frequent and
deadly diseases. Gastrokine1 (GKN1) and gastrokine2 (GKN2) genes
are highly expressed in the normal stomach epithelium and play
important roles in maintaining the integrity and homeostasis of
stomach mucosal epithelial cells. In this study, 47 paired samples that
were grouped according to the types of gastric cancer and the clinical
characteristics of the patients, including gender and average of age.
They were investigated with gene expression analysis and mutation
screening by monitoring RT-PCR, SSCP and nucleotide sequencing
techniques. Both GKN1 and GKN2 genes were observed significantly
reduced found by (Wilcoxon signed rank test; p
Abstract: Wireless networks are built upon the open shared
medium which makes easy for attackers to conduct malicious
activities. Jamming is one of the most serious security threats to
information economy and it must be dealt efficiently. Jammer
prevents legitimate data to reach the receiver side and also it
seriously degrades the network performance. The objective of this
paper is to provide a general overview of jamming in wireless
network. It covers relevant works, different jamming techniques,
various types of jammers and typical prevention techniques.
Challenges associated with comparing several anti-jamming
techniques are also highlighted.
Abstract: Unsteady flow and heat transfer from a circular
cylinder in cross-flow is studied numerically. The governing
equations are solved by using finite volume method. Reynolds
number varies in range of 50 to 200; in this range flow is considered
to be laminar and unsteady. Al2O3 nanoparticle with volume fraction
in range of 5% to 20% is added to pure water. Effects of adding
nanoparticle to pure water on lift and drag coefficient and Nusselt
number is presented. Addition of Al2O3 has inconsiderable effect on
the value of drags and lift coefficient. However, it has significant
effect on heat transfer; results show that heat transfer of Al2O3
nanofluid is about 9% to 36% higher than pure water.
Abstract: The Petri nets are the first standard for business
process modeling. Most probably, it is one of the core reasons why
all new standards created afterwards have to be so reformed as to
reach the stage of mapping the new standard onto Petri nets. The paper presents a business process repository based on a
universal database. The repository provides the possibility the data
about a given process to be stored in three different ways. Business
process repository is developed with regard to the reformation of a
given model to a Petri net in order to be easily simulated. Two different techniques for business process simulation based on
Petri nets - Yasper and Woflan are discussed. Their advantages and
drawbacks are outlined. The way of simulating business process
models, stored in the Business process repository is shown.
Abstract: Within this paper, latest results on processing of energetic nanomaterials by means of the Spray Flash Evaporation technique are presented. This technology constitutes a highly effective and continuous way to prepare fascinating materials on the nano- and micro-scale. Within the process, a solution is set under high pressure and sprayed into an evacuated atomization chamber. Subsequent ultrafast evaporation of the solvent leads to an aerosol stream, which is separated by cyclones or filters. No drying gas is required, so the present technique should not be confused with spray dying. Resulting nanothermites, insensitive explosives or propellants and compositions are foreseen to replace toxic (according to REACH) and very sensitive matter in military and civil applications. Diverse examples are given in detail: nano-RDX (n-Cyclotrimethylentrinitramin) and nano-aluminum based systems, mixtures (n-RDX/n-TNT - trinitrotoluene) or even cocrystalline matter like n-CL-20/HMX (Hexanitrohexaazaisowurtzitane/ Cyclotetra-methylentetranitramin). These nanomaterials show reduced sensitivity by trend without losing effectiveness and performance. An analytical study for material characterization was performed by using Atomic Force Microscopy, X-Ray Diffraction, and combined techniques as well as spectroscopic methods. As a matter of course, sensitivity tests regarding electrostatic discharge, impact, and friction are provided.
Abstract: Steel extended end plate bolted connections are
recommended to be widely utilized in special moment-resisting frame
subjected to monotonic loading. Improper design of steel beam to
column connection can lead to the collapse and fatality of structures.
Therefore comprehensive research studies of beam to column
connection design should be carried out. Also the performance and
effect of corrugated on the strength of beam column end plate
connection up to failure under monotonic loading in horizontal
direction is presented in this paper. The non-linear elastic–plastic
behavior has been considered through a finite element analysis using
the multi-purpose software package LUSAS. The effect of vertically
and horizontally types of corrugated web was also investigated.
Abstract: Machine visualization is an area of interest with fast
and progressive development. We present a method of machine
visualization which will be applicable in real industrial conditions
according to current needs and demands. Real factory data were
obtained in a newly built research plant. Methods described in this
paper were validated on a case study. Input data were processed and
the virtual environment was created. The environment contains
information about dimensions, structure, disposition, and function.
Hardware was enhanced by modular machines, prototypes, and
accessories. We added functionalities and machines into the virtual
environment. The user is able to interact with objects such as testing
and cutting machines, he/she can operate and move them. Proposed
design consists of an environment with two degrees of freedom of
movement. Users are in touch with items in the virtual world which
are embedded into the real surroundings. This paper describes development of the virtual environment. We
compared and tested various options of factory layout virtualization
and visualization. We analyzed possibilities of using a 3D scanner in
the layout obtaining process and we also analyzed various virtual
reality hardware visualization methods such as: Stereoscopic (CAVE)
projection, Head Mounted Display (HMD) and augmented reality
(AR) projection provided by see-through glasses.
Abstract: The agenda of showing the scheduled time for
performing certain tasks is known as timetabling. It is widely used in
many departments such as transportation, education, and production.
Some difficulties arise to ensure all tasks happen in the time and
place allocated. Therefore, many researchers invented various
programming models to solve the scheduling problems from several
fields. However, the studies in developing the general integer
programming model for many timetabling problems are still
questionable. Meanwhile, this thesis describes about creating a
general model which solves different types of timetabling problems
by considering the basic constraints. Initially, the common basic
constraints from five different fields are selected and analyzed. A
general basic integer programming model was created and then
verified by using the medium set of data obtained randomly which is
much similar to realistic data. The mathematical software, AIMMS
with CPLEX as a solver has been used to solve the model. The model
obtained is significant in solving many timetabling problems easily
since it is modifiable to all types of scheduling problems which have
same basic constraints.
Abstract: The aim of the study is to describe and analyze design
of mobile teaching for students collaborative learning in distance
higher education with a focus on mobile technologies as online
webinars (web-based seminars or conferencing) by using laptops,
smart phones, or tablets. These multimedia tools can provide face-toface
interactions, recorded flipped classroom videos and parallel chat
communications. The data collection consists of interviews with 22
students and observations of online face-to-face webinars, as well
two surveys. Theoretically, the study joins the research tradition of
Computer Supported Collaborative learning, CSCL, as well as
Computer Self-Efficacy, CSE concerned with individuals’ media and
information literacy. Important conclusions from the study
demonstrated mobile interactions increased student centered
learning. As the students were appreciating the working methods,
they became more engaged and motivated. The mobile technology
using among student also contributes to increased flexibility between
space and place, as well as media and information literacy.
Abstract: Numerical study of the static response of
homogeneous clay stratum considering a wide range of cohesion and
subject to foundation loads is presented. The linear elastic–perfectly
plastic constitutive relation with the von Mises yield criterion were
utilised to develop a numerically cost effective finite element model
for the soil while imposing a rigid body constrain to the foundation
footing. From the analyses carried out, estimate of the bearing
capacity factor, Nc as well as the ultimate load-carrying capacities of
these soils, effect of cohesion on foundation settlements, stress fields
and failure propagation were obtained. These are consistent with
other findings in the literature and hence can be a useful guide in
design of safe foundations in clay soils for buildings and other
structure.
Abstract: The analytical bright two soliton solution of the 3-
coupled nonlinear Schrödinger equations with variable coefficients in
birefringent optical fiber is obtained by Darboux transformation
method. To the design of ultra-speed optical devices, Soliton
interaction and control in birefringence fiber is investigated. Lax pair
is constructed for N coupled NLS system through AKNS method.
Using two-soliton solution, we demonstrate different interaction
behaviors of solitons in birefringent fiber depending on the choice of
control parameters. Our results shows that interactions of optical
solitons have some specific applications such as construction of logic
gates, optical computing, soliton switching, and soliton amplification
in wavelength division multiplexing (WDM) system.
Abstract: Broiler slaughter waste has become a major source of
pollution throughout the world. Utilization of broiler slaughter waste
by dry rendering process produced Rendered Chicken Oil (RCO), a
cheap raw material for biodiesel production and Carcass Meal a feed
ingredient for pets and fishes. Conversion of RCO into biodiesel may
open new vistas for generating wealth from waste besides controlling
the major havoc of environmental pollution. A two-step process to
convert RCO to good quality Biodiesel was invented. Acid catalysed
esterification of FFA followed by base catalysed transesterification of
triglycerides was carried out after meticulously standardizing the
methanol molar ratio, catalyst concentration, reaction temperature,
and reaction time to obtain the maximum biodiesel yield of 97.62%
and lowest glycerol yield of 6.96%. RCO biodiesel blend was tested
in a CRDI diesel engine. The results revealed that the blending of
commercial diesel with 20% RCO biodiesel (B20) lead to less engine
wear, a quieter engine and better fuel economy. The better lubricating
qualities of RCO B20 prevented over heating of engine, which
prolongs the engine life. RCO B20 can reduce the import of crude oil
and substantially reduce the engine emissions as proved by
significantly lower smoke levels, thus mitigating climatic changes.