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 Al-MoO3-P-CdTe-Al MOS sandwich structures
were fabricated by vacuum deposition method on cleaned glass
substrates. Capacitance versus voltage measurements were performed
at different frequencies and sweep rates of applied voltages for oxide
and semiconductor films of different thicknesses. In the negative
voltage region of the C-V curve a high differential capacitance of the
semiconductor was observed and at high frequencies (
Abstract: In its efforts to utilize the information and
communication technology to enhance the quality of public service
delivery, national and local governments around the world are
competing to introduce more ICT applications as tools to automate
processes related to law enforcement or policy execution, increase
citizen orientation, trust, and satisfaction, and create one-stop-shops
for public services. In its implementation, e-Government ICTs need
to maintain transparency, participation, and collaboration. Due to this
diverse of mixed goals and requirements, e-Government systems
need to be designed based on special design considerations in order
to eliminate the risks of failure to compliance to government
regulations, citizen dissatisfaction, or market repulsion.
In this article we suggest a framework with guidelines for
designing government information systems that takes into
consideration the special requirements of the public sector. Then we
introduce two case studies and show how applying those guidelines
would result in a more solid system design.
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: 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: 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: 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: 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: Theory of interpretation of electromagnetic fields studied in the electrical prospecting with direct current is mainly developed for the case of a horizontal surface observation. However in practice we often have to work in difficult terrain surface. Conducting interpretation without the influence of topography can cause non-existent anomalies on sections. This raises the problem of studying the impact of different shapes of ground surface relief on the results of electrical prospecting's research. This research examines the numerical solutions of the direct problem of electrical prospecting for two-dimensional and three-dimensional media, taking into account the terrain. The problem is solved using the method of integral equations. The density of secondary currents on the relief surface is obtained.
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: 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: 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: This paper presents circuit models to analyze the
conducted susceptibility of multiconductor shielded cables in
frequency domains using Branin’s method, which is referred to as the
method of characteristics. These models, which can be used directly
in the time and frequency domains, take into account the presence of
both the transfer impedance and admittance. The conducted
susceptibility is studied by using an injection current on the cable
shield as the source. Two examples are studied; a coaxial shielded
cable and shielded cables with two parallel wires (i.e., twinax cables).
This shield has an asymmetry (one slot on the side). Results obtained
by these models are in good agreement with those obtained by other
methods.
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: This study introduces two types of self-oscillating
circuits that are frequently found in power electronics applications.
Special effort is made to relate the circuits to the analogous mechanical
systems of some important scientific inventions: Galileo’s pendulum
clock and Coulomb’s friction model. A little touch of related history
and philosophy of science will hopefully encourage curiosity, advance
the understanding of self-oscillating systems and satisfy the aspiration
of some students for scientific literacy. Finally, the two self-oscillating
circuits are applied to design a simple class-D audio amplifier.