Abstract: Bio-composites derived from plant fiber and/or bioderived
polymer, are likely more ecofriendly and demonstrate
competitive performance with petroleum based composites. In this
research, the bio phenol-formaldehyde (bio-PF) was used as a matrix
and oil palm empty fruit bunch fiber (EFB) as reinforcement. The
matrix was synthesized via liquefaction and condensation to enhance
the combination of phenol and formaldehyde, during the process.
Then, the bio-PF was mixed with different percentage of EFB (5%,
10%, 15% and 20%) and molded at 180oC. The samples that viewed
under scanning electron microscopy (SEM) showed an excellent
wettability and interaction between EFB and matrix. Samples of 10%
EFB gave the optimum properties of impact and hardness meanwhile
sample 15% of EFB gave the highest reading of flexural modulus
(MOE) and flexural strength (MOR). For thermal stability analysis, it
was found that the weight loss and the activation energy (Ea) of the
bio-composites samples were decreased as the filler content
increased.
Abstract: Exact solution of an unsteady flow of elastico-viscous
fluid through a porous media in a tube of spherical 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suddenly withdrawn and the resulting fluid motion in a tube of
spherical 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,
porosity parameter of the bounding surface has significant effect on
the velocity parameter.
Abstract: Vegetation affects the mean and turbulent flow
structure. It may increase flood risks and sediment transport.
Therefore, it is important to develop analytical approaches for the bed
shear stress on vegetated bed, to predict resistance caused by
vegetation. In the recent years, experimental and numerical models
have both been developed to model the effects of submerged
vegetation on open-channel flow. In this paper, different analytic
models are compared and tested using the criteria of deviation, to
explore their capacity for predicting the mean velocity and select the
suitable one that will be applied in real case of rivers. The
comparison between the measured data in vegetated flume and
simulated mean velocities indicated, a good performance, in the case
of rigid vegetation, whereas, Huthoff model shows the best
agreement with a high coefficient of determination (R2=80%) and the
smallest error in the prediction of the average velocities.
Abstract: The California Bearing Ratio (CBR) has been
acknowledged as an important parameter to characterize the bearing
capacity of earth structures, such as earth dams, road embankments,
airport runways, bridge abutments and pavements. Technically, the
CBR test can be carried out in the laboratory or in the field. The CBR
test is time-consuming and is infrequently performed due to the
equipment needed and the fact that the field moisture content keeps
changing over time. Over the years, many correlations have been
developed for the prediction of CBR by various researchers,
including the dynamic cone penetrometer, undrained shear strength
and Clegg impact hammer. This paper reports and discusses some of
the results from a study on the prediction of CBR. In the current
study, the CBR test was performed in the laboratory on some finegrained
subgrade soils collected from various locations in Victoria.
Based on the test results, a satisfactory empirical correlation was
found between the CBR and the physical properties of the
experimental soils.
Abstract: Water contamination by toxic compound is one of the serious environmental problems today. These toxic compounds mostly originated from industrial effluents, agriculture, natural sources and human waste. These studies focus on modification of multiwalled carbon nanotube (MWCNTs) with nanoparticle of calixarene and explore the possibility of using this modification for the remediation of cadmium in water. The nanocomposites were prepared by dissolving calixarene in chloroform solution as solvent, followed by additional multiwalled carbon nanotube (MWCNTs) then sonication process for 3 hour and fabricated the nanocomposites on substrate by spin coating method. Finally, the nanocomposites were tested on cadmium ion (10 mg/ml). The morphology of nanocomposites was investigated by FESEM showing the formation of calixarene on the outer walls of carbon nanotube and cadmium ion also clearly seen from the micrograph. This formation was supported by using energy dispersive x-ray (EDX). The presence of cadmium ions in the films, leads to some changes in the surface potential and Fourier Transform Infrared spectroscopy (FTIR).The nanocomposites MWCNTs-calixarene have potential for development of sensor for pollutant monitoring and nanoelectronics devices applications.
Abstract: The present work aims to throw light on the effects of
arcing in air on the surface state of contact pastilles made of silvernickel
Ag-Ni (60/40). Also, the photoelectric emission from these
electrical contacts has been investigated in the spectral range of 196-
256 nm. In order to study the effects of arcing on the EWF, the
metallic samples were subjected to electrical arcs in air, at
atmospheric pressure and room temperature, after that, they have
been introduced into the vacuum chamber of an experimental UHV
set-up for EWF measurements. Both Fowler method of isothermal
curves and linearized Fowler plots were used for the measurement of
the EWF by the photoelectric effect.
It has been found that the EWF varies with the number of applied
arcs. Thus, after 500 arcs in air, the observed EWF increasing is
probably due to progressive inclusion of oxide on alloy surface.
Microscopic examination is necessary to get better understandings on
EWF of silver alloys, for both virgin and arced electrical contacts.
Abstract: High Peak to Average Power Ratio (PAPR) of the
transmitted signal is a serious problem in multicarrier systems (MC),
such as Orthogonal Frequency Division Multiplexing (OFDM), or in
Multi-Carrier Code Division Multiple Access (MC-CDMA) systems,
due to large number of subcarriers. This effect is possible reduce with
some PAPR reduction techniques. Spreading sequences at the
presence of Saleh and Rapp models of high power amplifier (HPA)
have big influence on the behavior of system. In this paper we
investigate the bit-error-rate (BER) performance of MC-CDMA
systems. Basically we can see from simulations that the MC-CDMA
system with Iterative algorithm can be providing significantly better
results than the MC-CDMA system. The results of our analyses are
verified via simulation.
Abstract: Background: With the perceived pain and poor
function experienced following knee arthroplasty, patients usually
feel un-satisfied. Yet, a controversy still persists on the appropriate
operative technique that doesn’t affect proprioception much.
Purpose: This study compared the effects of Cruciate Retaining
(CR) and Posterior Stabilized (PS) total knee arthroplasty (TKA on
dynamic balance, pain and functional performance following
rehabilitation.
Methods: Thirty patients with CRTKA (group I), thirty with
PSTKA (group II) and fifteen indicated for arthroplasty but weren’t
operated on yet (group III) participated in the study. The mean age
was 54.53±3.44, 55.13±3.48 and 55.33±2.32 years and BMI
35.7±3.03, 35.7±1.99 and 35.73±1.03 kg/m2 for groups I, II and III
respectively. The Berg Balance Scale (BBS), WOMAC pain subscale
and Timed Up-and-Go (TUG) and Stair-Climbing (SC) tests were
used for assessment. Assessments were conducted four weeks preand
post-operatively, three, six and twelve months post-operatively
with the control group being assessed at the same time intervals. The
post-operative rehabilitation involved hospitalization (1st week),
home-based (2nd-4th weeks), and outpatient clinic (5th-12th weeks)
programs, follow-up to all groups for twelve months.
Results: The Mixed design MANOVA revealed that group I had
significantly lower pain scores and SC time compared with group II
three, six and twelve months post-operatively. Moreover, the BBS
scores increased significantly and the pain scores and TUG and SC
time decreased significantly six months post-operatively compared
with four weeks pre- and post-operatively and three months postoperatively
in groups I and II with the opposite being true four weeks
post-operatively. But no significant differences in BBS scores, pain
scores and TUG and SC time between six and twelve months postoperatively
in groups I and II.
Interpretation/Conclusion: CRTKA is preferable to PSTKA,
possibly due to the preserved human proprioceptors in the un-excised
PCL.
Abstract: A parametric study on circular thin-walled pipes
subjected to pure bending is performed. Both straight and curved
pipes are considered. Ratio D/t, initial pipe curvature and internal
pressure are the parameters varying in the analyses. The study is
mainly FEA-based.
It is found that negative curvatures (opposite to bending moment)
considerably increase stiffness and buckling limit of the pipe when no
internal pressure is acting and, similarly, positive curvatures decrease
the stiffness and buckling limit. For internal pressurised pipes the
effects of initial pipe curvature are less relevant. Results show that
this phenomenon is in relationship with the cross-section deformation
due to bending moment, which undergoes relevant ovalisation for no
pressurised pipes and little ovalisation for pressurised pipes.
Abstract: Recent research in neural networks science and
neuroscience for modeling complex time series data and statistical
learning has focused mostly on learning from high input space and
signals. Local linear models are a strong choice for modeling local
nonlinearity in data series. Locally weighted projection regression is
a flexible and powerful algorithm for nonlinear approximation in
high dimensional signal spaces. In this paper, different learning
scenario of one and two dimensional data series with different
distributions are investigated for simulation and further noise is
inputted to data distribution for making different disordered
distribution in time series data and for evaluation of algorithm in
locality prediction of nonlinearity. Then, the performance of this
algorithm is simulated and also when the distribution of data is high
or when the number of data is less the sensitivity of this approach to
data distribution and influence of important parameter of local
validity in this algorithm with different data distribution is explained.
Abstract: The main objective of this paper is study the influence
of carbon nano-tubes fibers and nano silica fibers on the
characteristic compressive strength and flexural strength on concrete
and cement mortar. Twelve tested specimens were tested with square
section its dimensions (4040 160) mm, divided into four groups.
The first and second group studied the effect of carbon nano-tubes
(CNTs) fibers with different percentage equal to 0.0, 0.11%, 0.22%,
and 0.33% by weight of cement and effect of nano-silica (nS) fibers
with different percentages equal to 0.0, 1.0%, 2.0%, and 3.0% by
weight of cement on the cement mortar. The third and fourth groups
studied the effect of CNTs fiber with different percentage equal to
0.0%, 0.11%, and 0.22% by weight of cement, and effect of nS fibers
with different percentages were equal to 0.0%, 1.0%, and 2.0% by
weight of cement on the concrete. The compressive strength and
flexural strength at 7, 28, and 90 days is determined. From analysis of
tested results concluded that the nano-fibers is more effective when
used with cement mortar more than used with concrete because of
increasing the surface area, decreasing the pore and the collection of
nano-fibers. And also by adding nano-fibers the improvement of
flexural strength of concrete and cement mortar is more than
improvement of compressive strength.
Abstract: In this study, composites were fabricated from oil
palm empty fruit bunch fiber and poly(lactic) acid by extrusion
followed by injection moulding. Surface of the fiber was pre-treated
by ultrasound in an alkali medium and treatment efficiency was
investigated by scanning electron microscopy (SEM) analysis and
Fourier transforms infrared spectrometer (FTIR). Effect of fiber
treatment on composite was characterized by tensile strength (TS),
tensile modulus (TM) and impact strength (IS). Furthermore,
biostrong impact modifier was incorporated into the treated fiber
composite to improve its impact properties. Mechanical testing
showed an improvement of up to 23.5% and 33.6% respectively for
TS and TM of treated fiber composite above untreated fiber
composite. On the other hand incorporation of impact modifier led to
enhancement of about 20% above the initial IS of the treated fiber
composite.
Abstract: The present study was undertaken to investigate the
effect of pre-aging and aging parameters (time and temperature) on
the mechanical properties of Al-Mg-Zn (7075) alloys. Ultimate
tensile strength, 0.5% offset yield strength and % elongation
measurements were carried out on specimens prepared from cast and
heat treated 7075 alloys. Aging treatments were carried out for the as
solution treated (SHT) specimens (after quenching in warm water).
The specimens were aged at different conditions; Natural aging was
carried out at room temperature for different periods of time. Double
aging was performed for SHT conditions (pre-aged at different time
and temperature followed by high temperature aging). Ultimate
tensile strength, yield strength and % elongation as a function of
different pre-aging and aging parameters are analyzed to acquire an
understanding of the effects of these variables and their interactions
on the mechanical properties of Be-treated 7075 alloys.
Abstract: Parameters of flow are calculated in vaneless diffusers
with relative width 0,014–0,10. Inlet angles of flow and similarity
criteria were varied. There is information on flow separation,
boundary layer development, configuration of streamlines.
Polytrophic efficiency, loss coefficient and recovery coefficient are
used to compare effectiveness of diffusers. The sample of
optimization of narrow diffuser with conical walls is presented. Three
wide diffusers with narrowing walls are compared. The work is made
in the R&D laboratory “Gas dynamics of turbo machines” of the TU
SPb.
Abstract: This paper presents a novel fractal antenna structure
proposed for UWB (Ultra – Wideband) applications. The frequency
band 3.1-10.6GHz released by FCC (Federal Communication
Commission) as the commercial operation of UWB has been chosen
as frequency range for this antenna based on coplanar waveguide
(CPW) feed and circular shapes fulfilled according to fractal
geometry. The proposed antenna is validated and designed by using
an FR4 substrate with overall area of 34x43 mm2. The simulated
results performed by CST-Microwave Studio and compared by ADS
(Advanced Design System) show good matching input impedance
with return loss less than -10dB between 2.9 GHz and 11 GHz.
Abstract: Universal modeling method well proven for industrial
compressors was applied for design of the high flow rate supersonic
stage. Results were checked by ANSYS CFX and NUMECA Fine
Turbo calculations. The impeller appeared to be very effective at
transonic flow velocities. Stator elements efficiency is acceptable at
design Mach numbers too. Their loss coefficient versus inlet flow
angle performances correlates well with Universal modeling
prediction. The impeller demonstrates ability of satisfactory operation
at design flow rate. Supersonic flow behavior in the impeller inducer
at the shroud blade to blade surface Φ des deserves additional study.
Abstract: Vancron 40, a nitrided powder metallurgical tool
Steel, is used in cold work applications where the predominant failure
mechanisms are adhesive wear or galling. Typical applications of
Vancron 40 are among others fine blanking, cold extrusion, deep
drawing and cold work rolls for cluster mills. Vancron 40 positive
results for cold work rolls for cluster mills and as a tool for some
severe metal forming process makes it competitive compared to other
type of work rolls that require higher precision, among others in cold
rolling of thin stainless steel, which required high surface finish
quality. In this project, three roll materials for cold rolling of stainless
steel strip was examined, Vancron 40, Narva 12B (a high-carbon,
high-chromium tool steel alloyed with tungsten) and Supra 3 (a
Chromium-molybdenum tungsten-vanadium alloyed high speed
steel). The purpose of this project was to study the depth profiles of
the ironed stainless steel strips, emergence of galling and to study the
lubrication performance used by steel industries. Laboratory
experiments were conducted to examine scratch of the strip, galling
and surface roughness of the roll materials under severe tribological
conditions. The critical sliding length for onset of galling was
estimated for stainless steel with four different lubricants. Laboratory
experiments result of performance evaluation of resistance capability
of rolls toward adhesive wear under severe conditions for low and
high reductions. Vancron 40 in combination with cold rolling
lubricant gave good surface quality, prevents galling of
metal surfaces and good bearing capacity.
Abstract: This paper introduces novel approaches to partitioning
and mapping in terms of model-based embedded multicore system
engineering and further discusses benefits, industrial relevance and
features in common with existing approaches. In order to assess
and evaluate results, both approaches have been applied to a real
industrial application as well as to various prototypical demonstrative
applications, that have been developed and implemented for
different purposes. Evaluations show, that such applications improve
significantly according to performance, energy efficiency, meeting
timing constraints and covering maintaining issues by using
the AMALTHEA platform and the implemented approaches.
Furthermore, the model-based design provides an open, expandable,
platform independent and scalable exchange format between
OEMs, suppliers and developers on different levels. Our proposed
mechanisms provide meaningful multicore system utilization since
load balancing by means of partitioning and mapping is effectively
performed with regard to the modeled systems including hardware,
software, operating system, scheduling, constraints, configuration and
more data.
Abstract: Many issues about the relationship between auditors in
auditing practices with its stakeholders often heard. It appears in
perspectives of bringing out the variety of phenomena affecting from
the audit practice of greed and not appreciating from the
independency of the audit profession and professional code of ethics.
It becomes a logical consequence in practicing of capitalism in
accounting. The main purpose of this article would like to uncover
the existing auditing practices in Indonesia, especially in Java that
associated with a strong influence of Javanese culture with reluctant
/”shy", politely, "legowo (gratefully accepted)", "ngemong"
(friendly), "not mentholo" (lenient), "tepo seliro" (tolerance),
"ngajeni" (respectful), "acquiescent" and also reveals its relationships
with Non Javanese culture in facing the conflict of interest in
practical of auditing world. The method used by interpretive
approach that emphasizes the role of language, interpret and
understand and see social reality as something other than a label,
name or concept. Global practices in auditing of each country have
particular cultures that affect the standard set by those regulatory
standards results the adaptation of IAS. The majority of parties in
Indonesia is dominated by Javanese racial regulators, so Java culture
is embedded in every audit practices and those conditions in Java
leads auditors in having similar behaviour, sometimes interfere with
standard Java code of conduct must be executed by an auditor.
Auditors who live in Java have the characters of Javanese culture that
is hard to avoid in the audit practice. However, practically, the
auditors still are relevant in their profession.
Abstract: It has experimentally been proved that the
performance of compression ignition (C.I.) engine is spray
characteristics related. In modern diesel engine the spray formation
and the eventual combustion process are the vital processes that offer
more challenges towards enhancing the engine performance. In the
present work the numerical simulation has been carried out for
evaporating diesel sprays using Fluent software. For computational
fluid dynamics simulation “Meshing” is done using Gambit software
before transmitting it into Fluent. The simulation is carried out using
hot bomb conditions under varying chamber conditions such as gas
pressure, nozzle diameter and fuel injection pressure. For comparison
purpose, the numerical simulations the chamber conditions were kept
the same as that of the experimental data. At varying chamber
conditions the spray penetration rates are compared with the existing
experimental results.