Abstract: In this study, the thermal and mechanical properties of
basalt fibre reinforced concrete were investigated. The volume
fractions of basalt fibre of (0.1, 0.2, 0.3, and 0.5% by total mix
volume) were used. Properties such as heat transfer, compressive and
splitting tensile strengths were examined. Results indicated that the
strength increases with increase the fibre content till 0.3% then there
is a slight reduction when 0.5% fibre used. Lower amount of heat
conducted through the thickness of concrete specimens than the
conventional concrete was also recorded.
Abstract: The paper presents a novel idea to control computer
mouse cursor movement with human eyes. In this paper, a working
of the product has been described as to how it helps the special
people share their knowledge with the world. Number of traditional
techniques such as Head and Eye Movement Tracking Systems etc.
exist for cursor control by making use of image processing in which
light is the primary source. Electro-oculography (EOG) is a new
technology to sense eye signals with which the mouse cursor can be
controlled. The signals captured using sensors, are first amplified,
then noise is removed and then digitized, before being transferred to
PC for software interfacing.
Abstract: Construction of tunnels is connected with high
uncertainty in the field of costs, construction period, safety and
impact on surroundings. Risk management became therefore a
common part of tunnel projects, especially after a set of fatal
collapses occurred in 1990's. Such collapses are caused usually by
combination of factors that can be divided into three main groups, i.e.
unfavourable geological conditions, failures in the design and
planning or failures in the execution.
This paper suggests a procedure enabling quantification of the
excavation risk related to extraordinary accidents using FTA and
ETA tools. It will elaborate on a common process of risk analysis and
enable the transfer of information and experience between particular
tunnel construction projects. Further, it gives a guide for designers,
management and other participants, how to deal with risk of such
accidents and how to make qualified decisions based on a
probabilistic approach.
Abstract: In this work, we experimentally study heat transfer
from exhaust particulate air of detergent spray drying tower to water
by using coiled tube heat exchanger. Water flows in the coiled
tubes, where air loaded with detergent particles of 43 micrometers
in diameter flows within the shell. Four coiled tubes with different
coil pitches are used in a counter-current flow configuration. We
investigate heat transfer coefficients of inside and outside the heat
transfer surfaces through 400 experiments. The correlations between
Nusselt number and Reynolds number, Prandtl number, mass flow
rate of particulates to mass flow rate of air ratio and coiled tube
pitch parameter are proposed. The correlations procured can be used
to predicted heat transfer between tube and shell of the heat
exchanger.
Abstract: Phase locked loops for data links operating at 10 Gb/s
or faster are low phase noise devices designed to operate with a low
jitter reference clock. Characterization of their jitter transfer function
is difficult because the intrinsic noise of the device is comparable to
the random noise level in the reference clock signal. A linear model
is proposed to account for the intrinsic noise of a PLL. The intrinsic
noise data of a PLL for 10 Gb/s links is presented. The jitter transfer
function of a PLL in a test chip for 12.8 Gb/s data links was
determined in experiments using the 400 MHz reference clock as the
source of simultaneous excitations over a wide range of frequency.
The result shows that the PLL jitter transfer function can be
approximated by a second order linear model.
Abstract: Power-line networks are widely used today for broadband data transmission. However, due to multipaths within the broadband power line communication (BPLC) systems owing to stochastic changes in the network load impedances, branches, etc., network or channel capacity performances are affected. This paper attempts to investigate the performance of typical medium voltage channels that uses Orthogonal Frequency Division Multiplexing (OFDM) techniques with Quadrature Amplitude Modulation (QAM) sub carriers. It has been observed that when the load impedances are different from line characteristic impedance channel performance decreases. Also as the number of branches in the link between the transmitter and receiver increases a loss of 4dB/branch is found in the signal to noise ratio (SNR). The information presented in the paper could be useful for an appropriate design of the BPLC systems.
Abstract: In vitro plant regeneration has been successfully obtained from basal shoot explant of Vetiveria zizanioides through indirect organogenesis. The explant was cultured in Murashige & Skoog’s (MS) media supplemented with 2,4-D, IAA, and kinetin in various concentrations. Callus was well induced in media supplemented with 2 ppm 2,4-D, 1 ppm IAA, and 1 ppm kinetin. This callus was then transferred to MS media supplemented with 1 - 5 ppm of BAP for shoot regeneration. The media supplemented with 3 ppm BAP was a suitable medium for shoot induction, as well as for shoot multiplication. Rooting was well developed in shoot following transferred to half MS media containing 0.2 ppm IBA. Plantlet was then transferred to husk charcoal for acclimatization, and almost all (90%) of plantlets were survived during acclimatization.
Abstract: An analysis is made of the flow of an incompressible viscoelastic fluid (of small memory) over a porous plate subject to suction or blowing. It is found that velocity at a point increases with increase in the elasticity in the fluid. It is also shown that wall shear stress depends only on suction and is also independent of the material of fluids. No steady solution for velocity distribution exists when there is blowing at the plate. Temperature distribution in the boundary layer is determined and it is found that temperature at a point decreases with increase in the elasticity in the fluid.
Abstract: The radiative exchange method is introduced as a
numerical method for the simulation of radiative heat transfer in an
absorbing, emitting and isotropically scattering media. In this
method, the integro-differential radiative balance equation is solved
by using a new introduced concept for the exchange factor. Even
though the radiative source term is calculated in a mesh structure that
is coarser than the structure used in computational fluid dynamics,
calculating the exchange factor between different coarse elements by
using differential integration elements makes the result of the method
close to that of integro-differential radiative equation. A set of
equations for calculating exchange factors in two and threedimensional
Cartesian coordinate system is presented, and the
method is used in the simulation of radiative heat transfer in twodimensional
rectangular case and a three-dimensional simple cube.
The result of using this method in simulating different cases is
verified by comparing them with those of using other numerical
radiative models.
Abstract: This article discusses the concept of student ownership of knowledge and seeks to determine how to move students from knowledge acquisition to knowledge application and ultimately to knowledge generation in a virtual setting. Instructional strategies for fostering student engagement in a virtual environment are critical to the learner-s strategic ownership of the knowledge. A number of relevant theories that focus on learning, affect, needs and adult concerns are presented to provide a basis for exploring the transfer of knowledge from teacher to learner. A model under development is presented that combines the dimensions of knowledge approach, the teacher-student relationship with regards to knowledge authority and teaching approach to demonstrate the recursive and scaffolded design for creation of virtual learning environments.
Abstract: Perishable goods constitute a large portion of retailer inventory and lose value with time due to deterioration and/or obsolescence. Retailers dealing with such goods required considering the factors of short shelf life and the dependency of sales on inventory displayed in determining optimal procurement policy. Many retailers follow the practice of using two bins - primary bin sales fresh items at a list price and secondary bin sales unsold items at a discount price transferred from primary bin on attaining certain age. In this paper, mathematical models are developed for primary bin and for secondary bin that maximizes profit with decision variables of order quantities, optimal review period and optimal selling price at secondary bin. The demand rates in two bins are assumed to be deterministic and dependent on displayed inventory level, price and age but independent of each other. The validity of the model is shown by solving an example and the sensitivity analysis of the model is also reported.
Abstract: Sputter deposition processes, especially for sputtering
from metal targets, are well investigated. For practical reasons, i.e.
for industrial processes, energetic considerations for sputter
deposition are useful in order to optimize the sputtering process. In
particular, for substrates at floating conditions it is required to obtain
energetic conditions during film growth that enables sufficient dense
metal films of good quality. The influence of ion energies, energy
density and momentum transfer is thus examined both for sputtering
at the target as well as during film growth. Different regimes
dominated by ion energy, energy density and momentum transfer
were identified by using different plasma sources and by varying
power input, pressure and bias voltage.
Abstract: The major part of light weight timber constructions
consists of insulation. Mineral wool is the most commonly used
insulation due to its cost efficiency and easy handling. The fiber
orientation and porosity of this insulation material enables flowthrough.
The air flow resistance is low. If leakage occurs in the
insulated bay section, the convective flow may cause energy losses
and infiltration of the exterior wall with moisture and particles. In
particular the infiltrated moisture may lead to thermal bridges and
growth of health endangering mould and mildew. In order to prevent
this problem, different numerical calculation models have been
developed. All models developed so far have a potential for
completion. The implementation of the flow-through properties of
mineral wool insulation may help to improve the existing models.
Assuming that the real pressure difference between interior and
exterior surface is larger than the prescribed pressure difference in the
standard test procedure for mineral wool ISO 9053 / EN 29053,
measurements were performed using the measurement setup for
research on convective moisture transfer “MSRCMT".
These measurements show, that structural inhomogeneities of
mineral wool effect the permeability only at higher pressure
differences, as applied in MSRCMT. Additional microscopic
investigations show, that the location of a leak within the
construction has a crucial influence on the air flow-through and the
infiltration rate. The results clearly indicate that the empirical values
for the acoustic resistance of mineral wool should not be used for the
calculation of convective transfer mechanisms.
Abstract: This paper is to develop a fuzzy net present value (FNPV) method by taking vague cash flow and imprecise required rate of return into account for evaluating the value of the Build-Operate-Transfer (BOT) sport facilities. In order to clearly manifest a more realistic capital budgeting model based on the classical net present value (NPV) method, some uncertain financial elements in NPV formula will be fuzzified as triangular fuzzy numbers. Through the conscientious manipulation of fuzzy set theory, we will find that the proposed FNPV model is a more explicit extension of classical (crisp) model and could be more practicable for the financial managers to capture the essence of capital budgeting of sport facilities than non-fuzzy model.
Abstract: This study is designed to investigate errors emerged in written texts produced by 30 Turkish EFL learners with an explanatory, and thus, qualitative perspective. Erroneous language elements were identified by the researcher first and then their grammaticality and intelligibility were checked by five native speakers of English. The analysis of the data showed that it is difficult to claim that an error stems from only one single factor since different features of an error are triggered by different factors. Our findings revealed two different types of errors: those which stem from the interference of L1 with L2 and those which are developmental ones. The former type contains more global errors whereas the errors in latter type are more intelligible.
Abstract: In this study, the effect of nanofluids on the pool film
boiling was experimentally investigated at saturated condition under
atmospheric pressure. For this purpose, four different water-based
nanofluids (Al2O3, SiO2, TiO2 and CuO) with 0.1% particle volume
fraction were prepared. To investigate the boiling heat transfer, a
cylindrical rod with high temperature was used. The rod heated up to
high temperatures was immersed into nanofluids. The center
temperature of rod during the cooling process was recorded by using
a K-type thermocouple. The quenching curves showed that the pool
boiling heat transfer was strongly dependent on the nanoparticle
materials. During the repetitive quenching tests, the cooling time
decreased and thus, the film boiling vanished. Consequently, the
primary reason of this was the change of the surface characteristics
due to the nanoparticles deposition on the rod-s surface.
Abstract: The purpose of this work is fast design optimization of
the seal chamber. The study includes the mass transfer between lower
and upper chamber on seal chamber for hot water application pumps.
The use of Fluent 12.1 commercial code made it possible to capture
complex flow with heat-mass transfer, radiation, Tailor instability,
and buoyancy effect. Realizable k-epsilon model was used for
turbulence modeling. Radiation heat losses were taken into account.
The temperature distribution at seal region is predicted with respect
to heat addition.
Results show the possibilities of the model simplifications by
excluding the water domain in low chamber from calculations. CFD
simulations permit to improve seal chamber design to meet target
water temperature around the seal. This study can be used for the
analysis of different seal chamber configurations.
Abstract: This paper presents a methodology towards the emulation of the electrical power consumption of the RF device during the cellular phone/handset transmission mode using the LTE technology. The emulation methodology takes the physical environmental variables and the logical interface between the baseband and the RF system as inputs to compute the emulated power dissipation of the RF device. The emulated power, in between the measured points corresponding to the discrete values of the logical interface parameters is computed as a polynomial interpolation using polynomial basis functions. The evaluation of polynomial and spline curve fitting models showed a respective divergence (test error) of 8% and 0.02% from the physically measured power consumption. The precisions of the instruments used for the physical measurements have been modeled as intervals. We have been able to model the power consumption of the RF device operating at 5MHz using homotopy between 2 continuous power consumptions of the RF device operating at the bandwidths 3MHz and 10MHz.
Abstract: In this paper, Lattice Boltzmann Method (LBM) is used to study laminar flow with mixed convection heat transfer inside a two-dimensional inclined lid-driven rectangular cavity with aspect ratio AR = 3. Bottom wall of the cavity is maintained at lower temperature than the top lid, and its vertical walls are assumed insulated. Top lid motion results in fluid motion inside the cavity. Inclination of the cavity causes horizontal and vertical components of velocity to be affected by buoyancy force. To include this effect, calculation procedure of macroscopic properties by LBM is changed and collision term of Boltzmann equation is modified. A computer program is developed to simulate this problem using BGK model of lattice Boltzmann method. The effects of the variations of Richardson number and inclination angle on the thermal and flow behavior of the fluid inside the cavity are investigated. The results are presented as velocity and temperature profiles, stream function contours and isotherms. It is concluded that LBM has good potential to simulate mixed convection heat transfer problems.
Abstract: This paper demonstrates an effort of a serviceoriented
engineering department in improving the sharing and
transfer of knowledge. Although the department consist of only six
employees, but it provides services in various chemical application in
an oil and gas business. The services provided span across Asia
Pacific region mainly Indonesia, Myanmar, Vietnam, Brunei,
Thailand and Singapore. Currently there are no effective tools or
integrated systems that support the sharing or transfer and
maintenance of knowledge so the department has considered
preserving this valuable knowledge by developing a Knowledge
Management System (KMS). This paper presents the development of
a KMS to support the sharing of knowledge in a service-oriented
engineering department of an oil and gas company. The embedded
features in the KMS like blog and forum will encourage iterative
process of knowledge sharing among the employees in the
department. The information and knowledge being shared, discussed
and communicated will be then achieved for future re-use. The re-use
of the knowledge allows the department to reduce redundant efforts
in providing consistent, up-to-date and cost effective of the best
solution to the its clients.