Abstract: The key role in phenomenological modelling of cyclic
plasticity is good understanding of stress-strain behaviour of given
material. There are many models describing behaviour of materials
using numerous parameters and constants. Combination of individual
parameters in those material models significantly determines whether
observed and predicted results are in compliance. Parameter
identification techniques such as random gradient, genetic algorithm
and sensitivity analysis are used for identification of parameters using
numerical modelling and simulation. In this paper genetic algorithm
and sensitivity analysis are used to study effect of 4 parameters of
modified AbdelKarim-Ohno cyclic plasticity model. Results
predicted by Finite Element (FE) simulation are compared with
experimental data from biaxial ratcheting test with semi-elliptical
loading path.
Abstract: The paper presents a thermodynamic cycle analysis
for three turboshaft engines. The first cycle is a Brayton cycle,
describing the evolution of a classical turboshaft, based on the
Klimov TV2 engine. The other four cycles aim at approaching an
Ericsson cycle, by replacing the Brayton cycle adiabatic expansion in
the turbine by quasi-isothermal expansion. The maximum quasi-
Ericsson cycles temperature is set to a lower value than the maximum
Brayton cycle temperature, equal to the Brayton cycle power turbine
inlet temperature, in order to decrease the engine NOx emissions.
Also, the power/expansion ratio distribution over the stages of the gas
generator turbine is maintained the same. In two of the considered
quasi-Ericsson cycles, the efficiencies of the gas generator turbine, as
well as the power/expansion ratio distribution over the stages of the
gas generator turbine are maintained the same as for the reference
case, while for the other two cases, the efficiencies are increased in
order to obtain the same shaft power as in the reference case. For the
two cases respecting the first condition, both the shaft power and the
thermodynamic efficiency of the engine decrease, while for the other
two, the power and efficiency are maintained, as a result of assuming
new, more efficient gas generator turbines.
Abstract: In review the generalized data about biosynthetic routs
formation anthraquinone molecules in natural cells. The basic
possibilities of various ways of biosynthesis of different quinoid
substances are shown.
Abstract: Two finite element (FEM) models are presented in
this paper to address the random nature of the response of glued
timber structures made of wood segments with variable elastic
moduli evaluated from 3600 indentation measurements. This total
database served to create the same number of ensembles as was the
number of segments in the tested beam. Statistics of these ensembles
were then assigned to given segments of beams and the Latin
Hypercube Sampling (LHS) method was called to perform 100
simulations resulting into the ensemble of 100 deflections subjected
to statistical evaluation. Here, a detailed geometrical arrangement of
individual segments in the laminated beam was considered in the
construction of two-dimensional FEM model subjected to in fourpoint
bending to comply with the laboratory tests. Since laboratory
measurements of local elastic moduli may in general suffer from a
significant experimental error, it appears advantageous to exploit the
full scale measurements of timber beams, i.e. deflections, to improve
their prior distributions with the help of the Bayesian statistical
method. This, however, requires an efficient computational model
when simulating the laboratory tests numerically. To this end, a
simplified model based on Mindlin’s beam theory was established.
The improved posterior distributions show that the most significant
change of the Young’s modulus distribution takes place in laminae in
the most strained zones, i.e. in the top and bottom layers within the
beam center region. Posterior distributions of moduli of elasticity
were subsequently utilized in the 2D FEM model and compared with
the original simulations.
Abstract: The thermal control in many systems is widely
accomplished applying mixed convection process due to its low cost,
reliability and easy maintenance. Typical applications include the
aircraft electronic equipment, rotating-disc heat exchangers, turbo
machinery, and nuclear reactors, etc. Natural convection in an inclined
square enclosure heated via wall heater has been studied numerically.
Finite volume method is used for solving momentum and energy
equations in the form of stream function–vorticity. The right and left
walls are kept at a constant temperature, while the other parts are
adiabatic. The range of the inclination angle covers a whole revolution.
The method is validated for a vertical cavity. A general power law
dependence of the Nusselt number with respect to the Rayleigh
number with the coefficient and exponent as functions of the
inclination angle is presented. For a fixed Rayleigh number, the
inclination angle increases or decreases is found.
Abstract: Catalytic combustion of methane is imperative due to
stability of methane at low temperature. Methane (CH4), therefore,
remains unconverted in vehicle exhausts thereby causing greenhouse
gas GHG emission problem. In this study, heterogeneous catalysts of
palladium with bio-char (2 wt% Pd/Bc) and Al2O3 (2wt% Pd/ Al2O3)
supports were prepared by incipient wetness impregnation and then
subsequently tested for catalytic combustion of CH4. Support-porous
heterogeneous catalytic combustion (HCC) material were selected
based on factors such as surface area, porosity, thermal stability,
thermal conductivity, reactivity with reactants or products, chemical
stability, catalytic activity, and catalyst life. Sustainable and
renewable support-material of bio-mass char derived from palm shell
waste material was compared with those from the conventional
support-porous materials. Kinetic rate of reaction was determined for
combustion of methane on Palladium (Pd) based catalyst with Al2O3
support and bio-char (Bc). Material characterization was done using
TGA, SEM, and BET surface area. The performance test was
accomplished using tubular quartz reactor with gas mixture ratio of
3% methane and 97% air. The methane porous-HCC conversion was
carried out using online gas analyzer connected to the reactor that
performed porous-HCC. BET surface area for prepared 2 wt% Pd/Bc
is smaller than prepared 2wt% Pd/ Al2O3 due to its low porosity
between particles. The order of catalyst activity based on kinetic rate
on reaction of catalysts in low temperature was 2wt%
Pd/Bc>calcined 2wt% Pd/ Al2O3> 2wt% Pd/ Al2O3>calcined 2wt%
Pd/Bc. Hence agro waste material can successfully be utilized as an
inexpensive catalyst support material for enhanced CH4 catalytic
combustion.
Abstract: This article discusses ways to implement a
differentiated approach to developing academic motivation for
mathematical studies which relies on defining the primary structural
characteristics of motivation. The following characteristics are
considered: features of realization of cognitive activity, meaningmaking
characteristics, level of generalization and consistency of
knowledge acquired by personal experience. The assessment of the
present level of individual student understanding of each component
of academic motivation is the basis for defining the relevant
educational strategy for its further development.
Abstract: Array-based gene expression analysis is a powerful
tool to profile expression of genes and to generate information on
therapeutic effects of new anti-cancer compounds. Anti-apoptotic
effect of thymoquinone was studied in MCF7 breast cancer cell line
using gene expression profiling with cDNA microarray. The purity
and yield of RNA samples were determined using RNeasyPlus Mini
kit. The Agilent RNA 6000 NanoLabChip kit evaluated the quantity
of the RNA samples. AffinityScript RT oligo-dT promoter primer
was used to generate cDNA strands. T7 RNA polymerase was used to
convert cDNA to cRNA. The cRNA samples and human universal
reference RNA were labelled with Cy-3-CTP and Cy-5-CTP,
respectively. Feature Extraction and GeneSpring softwares analysed
the data. The single experiment analysis revealed involvement of 64
pathways with up-regulated genes and 78 pathways with downregulated
genes. The MAPK and p38-MAPK pathways were
inhibited due to the up-regulation of PTPRR gene. The inhibition of
p38-MAPK suggested up-regulation of TGF-ß pathway. Inhibition of
p38-MAPK caused up-regulation of TP53 and down-regulation of
Bcl2 genes indicating involvement of intrinsic apoptotic pathway.
Down-regulation of CARD16 gene as an adaptor molecule regulated
CASP1 and suggested necrosis-like programmed cell death and
involvement of caspase in apoptosis. Furthermore, down-regulation
of GPCR, EGF-EGFR signalling pathways suggested reduction of
ER. Involvement of AhR pathway which control cytochrome P450
and glucuronidation pathways showed metabolism of Thymoquinone.
The findings showed differential expression of several genes in
apoptosis pathways with thymoquinone treatment in estrogen
receptor-positive breast cancer cells.
Abstract: In the past few decades, the field of chemistry
education has grown tremendously and researches indicated that after
traditional chemistry instruction students often lacked deep
conceptual understanding and failed to integrate their ideas into
coherent conceptual framework. For several concepts in chemistry,
students at all levels have demonstrated difficulty in changing their
initial perceptions. Their perceptions are most often wrong and don't
agree with correct scientific concepts. This study explored the
effectiveness of intervention discussion sections for a college general
chemistry course designed to apply research on students
preconceptions, knowledge integration and student explanation.
Three interventions discussions lasting three hours on bond energy
and spontaneity were done tested and intervention (treatment)
students’ performances were compared with that of control group
which did not use the experimental pedagogy. Results indicated that
this instruction which was capable of identifying students'
misconceptions, initial conceptions and integrating those ideas into
class discussion led to enhanced conceptual understanding and better
achievement for the experimental group.
Abstract: Solid waste management in steel industry is broadly
classified in “4 Rs” i.e. reduce, reuse, recycle and restore the
materials. Reuse and recycling the entire solid waste generated in the
process of steel making is a viable solution in targeting a clean, green
and zero waste technology leading to sustainable development of the
steel industry. Solid waste management has gained importance in
steel industry in view of its uncertainty, volatility and speculation due
to world competitive standards, rising input costs, scarcity of raw
materials and solid waste generated like in other sectors. The
challenges that the steel Industry faces today are the requirement of a
sustainable development by meeting the needs of our present
generation without compromising the ability of future generations.
Technologies are developed not only for gainful utilization of solid
wastes in manufacture of conventional products but also for
conversion of same in to completely new products.
Abstract: Power Regeneration in Refrigeration Plant concept
has been analyzed and has been shown to be capable of saving about
25% power in Cryogenic Plants with the Power Regeneration System
(PRS) running under nominal conditions. The innovative component
Compressor Expander Group (CEG) based on turbomachinery has
been designed and built modifying CETT compressor and expander,
both selected for optimum plant performance. Experiments have
shown the good response of the turbomachines to run with R404a as
working fluid. Power saving up to 12% under PRS derated conditions
(50% loading) has been demonstrated. Such experiments allowed
predicting a power saving up to 25% under CEG full load.
Abstract: The paper describes the OAS role in dispute
resolution. The authors make an attempt to identify a general pattern
of the OAS activities within the peaceful settlement of interstate
conflicts, in the beginning of 21st century, as well as to analyze some
features of Honduras–Belize, Nicaragua–Honduras, Honduras–El
Salvador, Costa-Rica–Nicaragua, Colombia–Ecuador cases.
Abstract: In this paper we consider the equation of motion for
the F (R, T) gravity on their property of conformal invariance. It
is shown that in the general case, such a theory is not conformal
invariant. Studied special cases for the functions v and u in which
can appear properties of the theory. Also we consider cosmological
aspects F (R, T) theory of gravity, having considered particular case
F (R, T) = μR+νT^2. Showed that in this case there is a nonlinear
dependence of the parameter equation of state from time to time,
which affects its evolution.
Abstract: Now in some countries of the world the cellular
market is on the point of saturation, in others - positive dynamics of
development kept on. The reasons for it are also different, but there
are united by their general susceptibility to innovation changes, if
they are really innovative. If to take as an example the cellular market
of Kazakhstan it is defined by the low percent of smart phones at
consumers, the low population density, undercapacity of the 3G
channel, and absence of universal access to the LTE technology that
limits dynamical growth of this branch. These moments are
aggravated by failures of starting commercial projects by private
companies which prevent to be implemented and widely adopted to a
new product among consumers. The object of the research is possible
integration of wireless and program technologies at which
introduction the idea can regenerate in an innovation. The analysis of
existing projects in the market and the possible union of the
technologies through a prism of theoretical bases of innovative
activity shows that efficiency of the company by development and
introduction of innovations is possible only thanks to strict
observance of all terms and conditions of the innovative process
which main term is profit. Despite that fact that on a global scale the
innovativeness issue of companies is very popular, there are no
researches about possibility of innovative breaks in the field of
wireless access to the Internet in the cellular market of Kazakhstan.
Abstract: The present work describes the implementation of the
Enhanced Collaborative Optimization (ECO) multilevel architecture
with a gradient-based optimization algorithm with the aim of
performing a multidisciplinary design optimization of a generic
unmanned aerial vehicle with morphing technologies. The concepts
of weighting coefficient and dynamic compatibility parameter are
presented for the ECO architecture. A routine that calculates the
aircraft performance for the user defined mission profile and vehicle’s
performance requirements has been implemented using low fidelity
models for the aerodynamics, stability, propulsion, weight, balance
and flight performance. A benchmarking case study for evaluating
the advantage of using a variable span wing within the optimization
methodology developed is presented.
Abstract: Advances in the use of health care technology have
resulted in increased adverse events (AEs) related to the use of
medical devices. The study focused on the existing reporting systems.
This study was conducted in a tertiary care public sector hospital.
Devices included Syringe infusion pumps, Cardiac monitors, Pulse
oximeters, Ventilators and Defibrillators. A total of 211 respondents
were recruited. Interviews were held with 30 key informants. Medical
records were scrutinized. Relevant statistical tests were used.
Resident doctors reported maximum frequency of AEs, followed
by nurses; and least by consultants. A significant association was
found between the cadre of health care personnel and awareness that
the patients and bystanders have a risk of sustaining AE. Awareness
regarding reporting of AEs was low, and it was generally done
verbally. Other critical findings are discussed in the light of the
barriers to reporting, reasons for non-compliance, recording system,
and so on.
Abstract: Exact solution of an unsteady flow of elastico-viscous
fluid through a porous media in a tube of ellipsoidal cross section
under the influence of constant pressure gradient has been obtained in
this paper. Initially, the flow is generated by a constant pressure
gradient. After attaining the steady state, the pressure gradient is
suddenly withdrawn and the resulting fluid motion in a tube of
ellipsoidal cross section by taking into account of the porosity factor
of the bounding surface is investigated. The problem is solved in twostages
the first stage is a steady motion in tube under the influence of
a constant pressure gradient, the second stage concern with an
unsteady motion. The problem is solved employing separation of
variables technique. The results are expressed in terms of a nondimensional
porosity parameter (K) and elastico-viscosity parameter
(β), which depends on the Non-Newtonian coefficient. The flow
parameters are found to be identical with that of Newtonian case as
elastic-viscosity parameter tends to zero and porosity tends to
infinity. It is seen that the effect of elastico-viscosity parameter and
the porosity parameter of the bounding surface has significant effect
on the velocity parameter.
Abstract: This paper shows an experimental testing of a small
unit for combustion of solid fuels, such as charcoal and wood logs,
that can provide electricity. One of the concepts is that the unit does
not require qualified personnel for its operation. The unit itself is
composed of two main parts. The design requires a heat producing
stove and electricity producing thermoelectric generator. After the
construction the unit was tested and the results show that the
emission release is within the legislative requirements for emission
production and environmental protection. That qualifies such unit for
indoor application.
Abstract: Nowadays, huge amount of multimedia repositories
make the browsing, retrieval and delivery of video contents very slow
and even difficult tasks. Video summarization has been proposed to
improve faster browsing of large video collections and more efficient
content indexing and access. In this paper, we focus on approaches to
video summarization. The video summaries can be generated in many
different forms. However, two fundamentals ways to generate
summaries are static and dynamic. We present different techniques
for each mode in the literature and describe some features used for
generating video summaries. We conclude with perspective for
further research.
Abstract: Contemporary city is a subject to rapid economic and
social changes. Therefore, it requires an active policy designed to
meet the diverse needs of their residents, build competitive position
and capacity to compete with other cities. Competitiveness of cities
depends largely on their resources but also to a large extent, on the
policies and performance of local authorities. Cooperation with social
sector also plays an important role, as it affects the use of resources
and builds an advantage over other cities.
The subject of this article is city's contemporary problems of
development with particular emphasis on central areas. This issue is a
starting point for reflection on the process of urban regeneration in
medium size cities in Poland, as well as cooperation between various
actors and their roles in the revitalization processes of Polish cities'
centers.