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: An experimental study was performed to investigate
the behavior and strength of proposed technique to connect
reinforced concrete (RC) beam to steel or composite columns. This
approach can practically be used in several types of building
construction. In this technique, the main beam of the frame consists
of a transfer part (part of beam; Tr.P) and a common reinforcement
concrete beam. The transfer part of the beam is connected to the
column, whereas the rest of the beam is connected to the transfer part
from each side. Four full-scale beam-column connections were tested
under static loading. The test parameters were the length of the
transfer part and the column properties. The test results show that
using of the transfer part technique leads to modify the deformation
capabilities for the RC beam and hence it increases its resistance
against failure. Increase in length of the transfer part did not
necessarily indicate an enhanced behavior. The test results contribute
to the characterization of the connection behavior between RC beam -
steel column and can be used to calibrate numerical models for the
simulation of this type of connection.
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: Ionic liquids consisting of a phosphonium cationic
moiety and a saccharinate anion are synthesized and compared with
their precursors, phosphonium chlorides, in reference to their
extraction efficiency towards L-lactic acid. On the base of
measurements of the acid and the water partitioning in the
equilibrium biphasic systems, the molar ratios between acid, water
and ionic liquid are estimated which allows to deduce the lactic acid
extractive pathway. The effect of a salting-out addition that
strengthens hydrophobicity in both phases is studied in view to reveal
the best biphasic system with respect to IL low toxicity and high
extraction efficiency.
Abstract: Adolescents with Autism Spectrum Disorders (ASD)
often experience social-communication difficulties that negatively
impact their social interactions with typical peers. However, unlike
other age and disability groups, there is little intervention research to
inform best practice for these students. One evidence-based strategy
for younger students with ASD is peer-mediated intervention (PMI).
PMI may be particularly promising for use with adolescents, as peers
are readily available and are natural experts for encouraging authentic
high school conversations. This paper provides a review of previous
research that evaluated the use of PMI to improve the socialcommunication
skills of students with ASD. Specific intervention
features associated with positive student outcomes are identified and
recommendations for future research are provided. Adolescents with
ASD are targeted due the critical importance of social conversation at
the high school level.
Abstract: Modern Portfolio Theory (MPT) according to
Markowitz states that investors form mean-variance efficient
portfolios which maximizes their utility. Markowitz proposed the
standard deviation as a simple measure for portfolio risk and the
lower semi-variance as the only risk measure of interest to rational
investors. This paper uses a third volatility estimator based on
intraday data and compares three efficient frontiers on the Croatian
Stock Market. The results show that range-based volatility estimator
outperforms both mean-variance and lower semi-variance model.
Abstract: To determine the potential of a low cost Irish
engineered timber product to replace high cost solid timber for use in
bending active structures such as gridshells a single Irish engineered
timber product in the form of orientated strand board (OSB) was
selected. A comparative study of OSB and solid timber was carried
out to determine the optimum properties that make a material suitable
for use in gridshells. Three parameters were identified to be relevant
in the selection of a material for gridshells. These three parameters
are the strength to stiffness ratio, the flexural stiffness of
commercially available sections, and the variability of material and
section properties. It is shown that when comparing OSB against
solid timber, OSB is a more suitable material for use in gridshells that
are at the smaller end of the scale and that have tight radii of
curvature. Typically, for solid timber materials, stiffness is used as an
indicator for strength and engineered timber is no different. Thus, low
flexural stiffness would mean low flexural strength. However, when
it comes to bending active gridshells, OSB offers a significant
advantage. By the addition of multiple layers, an increased section
size is created, thus endowing the structure with higher stiffness and
higher strength from initial low stiffness and low strength materials
while still maintaining tight radii of curvature. This allows OSB to
compete with solid timber on large scale gridshells. Additionally, a
preliminary sustainability study using a set of sustainability indicators
was carried out to determine the relative sustainability of building a
large-scale gridshell in Ireland with a primary focus on economic
viability but a mention is also given to social and environmental
aspects. For this, the Savill garden gridshell in the UK was used as
the functional unit with the sustainability of the structural roof
skeleton constructed from UK larch solid timber being compared
with the same structure using Irish OSB. Albeit that the advantages of
using commercially available OSB in a bending active gridshell are
marginal and limited to specific gridshell applications, further study
into an optimised engineered timber product is merited.
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: Nitrogen fertilizer is the most used and often the most
mismanaged nutrient input. Nitrogen management has tremendous
implications on crop productivity, quality and environmental
stewardship. Sufficient nitrogen is needed to optimum yield and
quality. Soil and in-season plant tissue testing for nitrogen status are
a time consuming and expensive process. Real time sensing of plant
nitrogen status can be a useful tool in managing nitrogen inputs. The
objectives of this project were to assess the reliability of remotely
sensed non-destructive plant nitrogen measurements compared to wet
chemistry data from sampled plant tissue, develop in-season nitrogen
recommendations based on remotely sensed data for improved
nitrogen use efficiency and assess the potential for determining yield
and quality from remotely sensed data. Very good correlations were
observed between early-season remotely sensed crop nitrogen status
and plant nitrogen concentrations and subsequent in-season fertilizer
recommendations. The transmittance/absorbance type meters gave
the most accurate readings. Early in-season fertilizer recommendation
would be to apply 40 kg nitrogen per hectare plus 15 kg nitrogen per
hectare for each unit difference measured with the SPAD meter
between the crop and reference area or 25 kg plus 13 kg per hectare
for each unit difference measured with the CCM 200. Once the crop
was sufficiently fertilized meter readings became inconclusive and
were of no benefit for determining nitrogen status, silage yield and
quality and grain yield and protein.
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: 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: 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 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: Over the years, it has been extensively established that
the practice of assuming a structure being fixed at base, leads to gross
errors in evaluation of its overall response due to dynamic loadings
and overestimations in design. The extent of these errors depends on
a number of variables; soil type being one of the major factor. This
paper studies the effect of Soil Structure Interaction (SSI) on multistorey
buildings with varying under-laying soil types after proper
validation of the effect of SSI. Analysis for soft, stiff and very stiff
base soils has been carried out, using a powerful Finite Element
Method (FEM) software package ANSYS v14.5. Results lead to
some very important conclusions regarding time period, deflection
and acceleration responses.
Abstract: Semiconductor crystals smaller than about 10 nm,
known as quantum dots, have properties that differ from large
samples, including a band gap that becomes larger for smaller
particles. These properties create several applications for quantum
dots. In this paper new shapes of quantum dot arrays are used to
enhance the photo physical properties of gold nano-particles. This
paper presents a study of the effect of nano-particles shape, array, and
size on their absorption characteristics.