Abstract: Chemical vapor deposition (CVD) diamond coated
cutting tool has excellent cutting performance, it is the most ideal tool
for the processing of nonferrous metals and alloys, composites,
nonmetallic materials and other difficult-to-machine materials
efficiently and accurately. Depositing CVD diamond coating on the
cemented carbide with high cobalt content can improve its toughness
and strength, therefore, it is very important to research on the
preparation technology and cutting properties of CVD diamond coated
cemented carbide cutting tool with high cobalt content. The
preparation technology of boron-doped diamond (BDD) coating has
been studied and the coated drills were prepared. BDD coating were
deposited on the drills by using the optimized parameters and the SEM
results show that there are no cracks or collapses in the coating.
Cutting tests with the prepared drills against the silumin and aluminum
base printed circuit board (PCB) have been studied. The results show
that the wear amount of the coated drill is small and the machined
surface has a better precision. The coating does not come off during
the test, which shows good adhesion and cutting performance of the
drill.
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: Hybrid bioreactor having both suspended-growth and
attached-growth bacteria is found a novel and excellent bioreactor
system for treating the municipal wastewater containing inhibitory
substrates too. In this reactor a fraction of substrate is used by
suspended biomass and the remaining by attached biomass resulting
in the competition between the two growths for the substrate. The
combination of suspended and attached growth provides the system
with enhanced biomass concentration and sludge age more than those
in ASP. Similar to attached growth system, the hybrid bioreactor
ensures considerable efficiency for treating toxic and refractory
substances in wastewater. For the process design of hybrid bioreactor
a suitable mathematical model is required. Although various
mathematical models were developed on hybrid bioreactor in due
course of time in earlier research works, none of them was found
having a specific simplified solution of the corresponding models and
without having any drawback. To overcome this drawback authors
already developed a simplified mathematical model for process
design of a hybrid bioreactor. The present paper briefly highlights on
the various aspects of process design of an aerobic hybrid bioreactor
for the treatment of municipal wastewater.
Abstract: The capability of CNC gantry milling machines in
manufacturing long components has caused the expanded use of such
machines. On the other hand, the machines’ gantry rigidity can
reduce under severe loads or vibration during operation. Indeed, the
quality of machining is dependent on the machine’s dynamic
behavior throughout the operating process. For this reason, these
types of machines have always been used widely and are not
efficient. Therefore, they can usually be employed for rough
machining and may not produce adequate surface finishing. In this
paper, a CNC gantry milling machine with the potential to produce
good surface finish has been designed and analyzed. The lowest
natural frequency of this machine is 202 Hz corresponding to 12000
rpm at all motion amplitudes with a full range of suitable frequency
responses. Meanwhile, the maximum deformation under dead loads
for the gantry machine is 0.565*m, indicating that this machine tool
is capable of producing higher product quality.
Abstract: The main aim of the presented experiments is to
improve behaviour of sandwich structures under dynamic loading,
such as crash or explosion. This paper describes experimental
investigation on the response of new advanced materials to low and
high velocity load. Blast wave energy absorbers were designed using
two types of porous lightweight raw particle materials based on
expanded glass and ceramics with dimensions of 0.5-1 mm,
combined with polymeric binder. The effect of binder amount on the
static and dynamic properties of designed materials was observed.
Prism shaped specimens were prepared and loaded to obtain physicomechanical
parameters – bulk density, compressive and flexural
strength under quasistatic load, the dynamic response was determined
using Split Hopkinson Pressure bar apparatus. Numerical
investigation of the material behaviour in sandwich structure was
performed using implicit/explicit solver LS-Dyna. As the last step,
the developed material was used as the interlayer of blast resistant
litter bin, and it´s functionality was verified by real field blast tests.
Abstract: The purpose of the present work was to develop an
innovative food product with nutritional properties as well as
appealing organoleptic qualities. The product, a jam, was prepared
with the beans’ cooking water combined with fresh apple or carrot,
without the addition of any conservatives. Three different jams were
produced: bean and carrot, bean and apple and bean, apple and
cinnamon. The developed products underwent a sensorial analysis
that revealed that the bean, apple and cinnamon jam was globally
better accepted. However, with this study, the consumers determined
that the bean and carrot jam had the most attractive color and the
bean and apple jam the better consistency. Additionally, it was
possible to analyze the jams for their chemical components, namely
fat, fiber, protein, sugars and antioxidant activity. The obtained
results showed that the bean and carrot jam had the highest lipid
content, while the bean, apple and cinnamon jam had the highest
fiber content, when compared to the other two jams. Regarding the
sugar content, both jams with apple revealed similar sugar values,
which were higher than the sugar content of the bean and carrot jam.
The antioxidant activity was on average 10 mg TE/g.
Abstract: In this paper we present the efficient parallel
implementation of elastoplastic problems based on the TFETI (Total
Finite Element Tearing and Interconnecting) domain decomposition
method. This approach allow us to use parallel solution and compute
this nonlinear problem on the supercomputers and decrease the
solution time and compute problems with millions of DOFs. In
our approach we consider an associated elastoplastic model with
the von Mises plastic criterion and the combination of linear
isotropic-kinematic hardening law. This model is discretized by
the implicit Euler method in time and by the finite element
method in space. We consider the system of nonlinear equations
with a strongly semismooth and strongly monotone operator. The
semismooth Newton method is applied to solve this nonlinear
system. Corresponding linearized problems arising in the Newton
iterations are solved in parallel by the above mentioned TFETI. The
implementation of this problem is realized in our in-house MatSol
packages developed in MatLab.
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: Using the pseudopotential technique the Sagdeev
potential equation has been derived in a plasma consisting of twotemperature
nonisothermal electrons, negatively charged dust grains
and warm positive ions. The study shows that the presence of
nonisothermal two-temperature electrons and charged dust grains
have significant effects on the excitation and structure of the ionacoustic
double layers in the model plasma under consideration. Only
compressive type double layer is obtained in the present plasma
model. The double layer solution has also been obtained by including
higher order nonlinearity and nonisothermality, which is shown to
modify the amplitude and deform the shape of the double layer.
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: In the present work, fly ash geopolymer based
composites including polyester (PES) waste were studied. Specimens
of three compositions were prepared: (a) fly ash geopolymer with 5%
PES waste; (b) fly ash geopolymer mortar with 5% PES waste; (c) fly
ash geopolymer mortar with 6.25% PES waste. Compressive and
bending strength measurements, water absorption test and
determination of thermal conductivity coefficient were performed.
The results showed that the addition of sand in a mixture of
geopolymer with 5% PES content led to higher compressive strength,
while it increased water absorption and reduced thermal conductivity
coefficient. The increase of PES addition in geopolymer mortars
resulted in a more dense structure, indicated by the increase of
strength and thermal conductivity and the decrease of water
absorption.
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: We address the integer frequency offset (IFO)
estimation under the influence of the timing offset (TO) in orthogonal
frequency division multiplexing (OFDM) systems. Incorporating the
IFO and TO into the symbol set used to represent the received
OFDM symbol, we investigate the influence of the TO on the IFO,
and then, propose a combining method between two consecutive
OFDM correlations, reducing the influence. The proposed scheme
has almost the same complexity as that of the conventional
schemes, whereas it does not need the TO knowledge contrary to
the conventional schemes. From numerical results it is confirmed
that the proposed scheme is insensitive to the TO, consequently,
yielding an improvement of the IFO estimation performance over
the conventional schemes when the TO exists.
Abstract: The Markov decision process (MDP) based
methodology is implemented in order to establish the optimal
schedule which minimizes the cost. Formulation of MDP problem
is presented using the information about the current state of pipe,
improvement cost, failure cost and pipe deterioration model. The
objective function and detailed algorithm of dynamic programming
(DP) are modified due to the difficulty of implementing the
conventional DP approaches. The optimal schedule derived from
suggested model is compared to several policies via Monte
Carlo simulation. Validity of the solution and improvement in
computational time are proved.
Abstract: This study aimed to identify the alignment of
understanding and assessment practices among secondary school
teachers. The study was carried out using quantitative descriptive
study. The sample consisted of 164 teachers who taught Form 1 and 2
from 11 secondary schools in the district of North Kinta, Perak,
Malaysia. Data were obtained from 164 respondents who answered
Expectation Alignment Understanding and Practices of School
Assessment (PEKDAPS) questionnaire. The data were analysed
using SPSS 17.0+. The Cronbach’s alpha value obtained through
PEKDAPS questionnaire pilot study was 0.86. The results showed
that teachers' performance in PEKDAPS based on the mean value
was less than 3, which means that perfect alignment does not occur
between the understanding and practices of school assessment. Two
major PEKDAPS sub-constructs of articulation across grade and age
and usability of the system were higher than the moderate alignment
of the understanding and practices of school assessment (Min=2.0).
The content focused of PEKDAPs sub-constructs which showed
lower than the moderate alignment of the understanding and practices
of school assessment (Min=2.0). Another two PEKDAPS subconstructs
of transparency and fairness and the pedagogical
implications showed moderate alignment (2.0). The implications of
the study is that teachers need to fully understand the importance of
alignment among components of assessment, learning and teaching
and learning objectives as strategies to achieve quality assessment
process.
Abstract: This paper discusses the design and analysis of a
hybrid PV-Fuel cell energy system destined to power a DC load. The
system is composed of a photovoltaic array, a fuel cell, an
electrolyzer and a hydrogen tank. HOMER software is used in this
study to calculate the optimum capacities of the power system
components that their combination allows an efficient use of solar
resource to cover the hourly load needs. The optimal system sizing
allows establishing the right balance between the daily electrical
energy produced by the power system and the daily electrical energy
consumed by the DC load using a 28 KW PV array, a 7.5 KW fuel
cell, a 40KW electrolyzer and a 270 Kg hydrogen tank. The variation
of powers involved into the DC bus of the hybrid PV-fuel cell system
has been computed and analyzed for each hour over one year: the
output powers of the PV array and the fuel cell, the input power of
the elctrolyzer system and the DC primary load. Equally, the annual
variation of stored hydrogen produced by the electrolyzer has been
assessed. The PV array contributes in the power system with 82%
whereas the fuel cell produces 18%. 38% of the total energy
consumption belongs to the DC primary load while the rest goes to
the electrolyzer.
Abstract: The dissimilar joint between aluminum/titanium
alloys (Al 6082 and Ti G2) were successfully achieved by CO2 laser
welding with a single pass and without filler material using the
overlap joint design. Laser welding parameters ranges combinations
were experimentally determined using Taguchi approach with the
objective of producing welded joint with acceptable welding profile
and high quality of mechanical properties. In this study a joining of
dissimilar Al 6082 / Ti G2 was resulted in three distinct regions
fusion area in the weldment. These regions are studied in terms of its
microstructural characteristics and microhardness which are directly
affecting the welding quality.
The weld metal was mainly composed of martensite alpha prime.
In two different metals in the two different sides of joint HAZ, grain
growth was detected. The microhardness of the joint distribution also
has shown microhardness increasing in the HAZ of two base metals
and a varying microhardness in fusion zone.
Abstract: In this paper, an explicit homotopic function is
constructed to compute the Hochschild homology of a finite
dimensional free k-module V. Because the polynomial algebra is of
course fundamental in the computation of the Hochschild homology
HH and the cyclic homology CH of commutative algebras, we
concentrate our work to compute HH of the polynomial algebra, by
providing certain homotopic function.