Doppler ultrasound is used in obstetrics and gynecology fields to serve as the complement
mode in the standard prenatal scan. It aids in investigating fetus blood flow in expectant
mothers’ wombs, usually those who come with pregnancy complications. In the conventional
ultrasound beam, the heat produced by attenuation is distributed over the area. However, the
Doppler ultrasound beam is focused at only one point. This leads the heat to accumulate at
that particular area and hence there is an increase in the temperature. Heat is considered as
a teratogen in pregnancy, whereby an increase in the fetal temperature can be fatal to the
fetus. Studies have found that Doppler mode is associated with higher acoustic output as
compared to the conventional two-dimensional (2D) ultrasound mode. Several studies done
on animals have ruled out the evidence of Doppler ultrasound bioeffects. This narrative
review only discusses the thermally induced effect of ultrasound by using Doppler mode.
This study reviews prior studies with keywords such as Doppler ultrasound, bioeffects,
heating effects, rabbit, and pregnancy. Earlier studies noted that the risk of thermal effects
increased with the increase of exposure time. However, Doppler ultrasound wave inducing
fetal hyperthermia is not the main reason for
causing adverse neonatal outcomes without
taking into account other external factors.
Therefore, it is essential for the practitioners
to adopt and adapt the concept of ‘as low as
reasonably achievable’ (ALARA) to avoid
any subtle adverse effects.
Cogeneration systems are extensively used in Malaysia to produce power as a primary
source. However, in the event of cogeneration system failure, the customer or the client are
forced to use a redundancy to avoid power interruptions. There are two methods commonly
used as a backup in the cogeneration systems which are Generator set and public utility. In
order to choose the best redundancy for a particular cogeneration system, it is essential to
evaluate the economic benefit analysis by considering several factors such as Maximum
demand charge, installation cost and Discount interest. In the evaluation of economic
benefit, this study identifies the number of failure and associated downtime using reliability
and availability approach, and then present value method was applied. The result shows
that the usage of public utility as redundancy is beneficial if the cogeneration system
operates within five years period. However, if the cogeneration system operates more than
five years, generator set option would be a better option to minimize the total cost. This
research also addresses the effect of various factors such as installation cost, maximum
demand charge, fuel cost, discount interest rate and production capacity. In general, the
output of the research would be beneficial for the plant operator to select the appropriate
redundancy option based on the economic advantages.
Cement Kiln Dust (CKD) is a by-product generated throughout the production of Ordinary
Portland Cement (OPC). It is normally emitted to the atmosphere or converted into liquid
and subsequently drained out as effluents to landfills and wastage areas. It impacted human
health and the environment negatively. However, it can be utilized in concrete as raw
cement replacement materials due to its engineering properties which work as an alternative
binder of OPC in addition to that it has benefits in creating economic and environmental
advantages. This study aimed to modify CKD and investigate the chemical composition
of normal-CKD and modified -CKD accordingly. The term modified noted that CKD has
gone through a process of modification using heating process. The reactivity property of
CKD was investigated using pH analysis. Then, mix proportions of different percentage
of normal-CKD and modified -CKD were developed to study the addition effects on
the compressive and flexural strength for different curing period. The trend of strength
development over the addition of CKD was also analyzed. OPC was replaced by CKD at
0% and successively increased by 10% to 100% through binder weight (OPC). A fixed
amount of water to binder (W/B) with a ratio of 0.45 was used for all hybrids. The mixes
were formed into the specimen and tested for compressive strength and flexural strength at
7, 14 and 28 curing days. The medium particle size of CKD used was less than 10μm. The
results of compressive and flexural strength showed that modified-CKD resulted in better
properties and 10% replacement showed
the maximum values of compressive and
flexural strength as a result considered best
percentage replacement in agreement with
its noteworthy results.
This review is aimed to present an in-depth review of several methodologies on magnetic
water treatment (MWT) that are employed as scale treatment in water pipeline and to
critically discuss each method in order to determine the best outcome of MWT. The
magnetically assisted water in pipeline in various applications are presented, argued and
best variables are listed according to the performance of each MWT. The advantages and
limitations of MWT are discussed and the main outcome from the review summarize the
best method in MWT, especially in effectiveness of treating scale in terms of sustained
environment benefits. Magnetic field application in water treatment has the potential to
improve the water pipeline performance and lifetime. The application is also significant in
controlling the growth of scale in upcoming system. Both of these benefits lead to healthier
water treatment, increasing and maintaining the lifetime and performance of water system.
(Kenaf fibre is a good reinforcement in fibre polymer composites due to its high strength
and elastic modulus, high stiffness, low density, low cost and eco-efficient, less health
hazards, renewability, good mechanical and thermal properties, and biodegradability. It is
traditionally used for rope, twine, fish net and sacking materials. Recently, it was observed
that kenaf fibre had huge potentials to replacing synthetic fibre in composites due to the
rising environmental and ecological issues, thus this awareness has motivated efforts for
the advancement of new innovative bio-based composites incorporating kenaf fibre for
various end-use structural applications. This paper presents an overview of the development
made so far in the area of kenaf fibre and its composites in terms of chemical and microstructural
properties, mechanical properties, dimensional stability, thermal stability, product
development and application. Some fundamental issues and suggestions for further research
in this area are also discussed.
Clustering is basically one of the major sources of primary data mining tools. It makes
researchers understand the natural grouping of attributes in datasets. Clustering is an
unsupervised classification method with the major aim of partitioning, where objects in the
same cluster are similar, and objects which belong to different clusters vary significantly,
with respect to their attributes. However, the classical Standardized Euclidean distance,
which uses standard deviation to down weight maximum points of the ith features on the
distance clusters, has been criticized by many scholars that the method produces outliers,
lack robustness, and has 0% breakdown points. It also has low efficiency in normal
distribution. Therefore, to remedy the problem, we suggest two statistical estimators
which have 50% breakdown points namely the Sn and Qn estimators, with 58% and 82%
efficiency, respectively. The proposed methods evidently outperformed the existing methods
in down weighting the maximum points of the ith features in distance-based clustering
analysis.
Merbok river catchment situated in the Kedah State receives its input from Bongkok River
and Puntar River flowing down and joining Lalang River to flow down to the Merbok
Estuary. The Merbok catchment (440 km2) is experiencing several degrees of complex
land uses activities that poses some impact on the suspended sediment production of
the Merbok river. A study was conducted to investigate the suspended sediment loading
of rivers draining the Merbok catchment from January to December 2013. Suspended
sediment budget of the Merbok catchment were estimated. The river suspended sediment
concentrations (SSC) and suspended sediment (SS) load increased during wet season
compared to dry season. The SS loads increases from upper catchment to river mouth. The
sediment loadings were divided into three segments- the upstream, middle segment and
lower segment. The SS loads increased from 10 t yr-1 in the upper part of Bongkok river
to 3336 t yr-1 in upper segment. The sediment loading then increase to 4299 t yr-1 in the
middle segment of the catchment (at Bongkok 4), and then exiting the Merbok Estuary, as
the lower segment, with a total amount of sediment output estimated at 7156 t yr-1. From this
total sediment output, most of the sediment
source came from the tributaries; the
Bongkok River at B3 (3337 t yr-1), Puntar
River (2924 t yr-1) and Lalang River (1370
t yr-1), which were much higher than its
proportion in terms of its length and drainage
area. As a conclusion, the inconsistence in
SSC in the river were influenced by the
various anthropogenic activities (especially
agriculture and urbanization activities) in the catchment area which necessitate future land use and sediment control to avoid sediment
and possible nutrient loading into the estuary.
Since 1958, most of the world’s countries including Turkey depend on the Empirical
Pavement Design Method established by AASHO (which is now known as AASHTO).
The limitation of the data used for preparing AASHTO 1993 and Non-Mechanical Based
procedure are the main reasons for the needs of new design procedure. The new AASHTO
design procedure MEPDG has been established in 2002 and adopted by most of the states
in the USA which is based on Mechanistic-Empirical (M-E) principles. The aim of this
paper is to prepare a plan for the implementation of MEPDG in TURKEY starting with
Third Region. The plan consists of two stages. Stage one is concerned with data collection
and preparing of input files. This stage is subdivided into three tasks namley, Climate File,
Material File and Traffic File. Stage two is associated with the use of the files prepared
in Stage one to conduct studies using MEPDG software. These studies are recommended
by AASHTO to evaluate the applicability of the procedure and the recommended
enhancements. The studies of this stage are: (a) Sensitivity Analysis of MEPDG to Design
Inputs; (b) Comparison of specific Third Region Designs with MEPDG designs; and (c)
Calibration of Performance Models for Third Region in Turkey. The outcomes of this
paper can be used as guidance for further studies on the implementation of MEPDG
in other Regions in Turkey. Also the results of these researches can be assembled to
implement the procedure for whole Turkey.
As we know, drinking young coconut water and eating the tender meat give many benefit
to the body for its nutritious value rather than its taste; but do we realize that it requires a
dangerous tasks in processing it. The process of trimming requires skills which only can
be obtained by those who run the work daily. Thus, a portable apparatus which has the
capabilities of reducing the hazardous tasks and fasten the time consumed for processing
the young coconut fruit has been proposed and developed. The development of the product
begins with collecting and analyzing the data of 30 young coconut fruits. Then, it is followed
by designing the whole product at main and component level. The conceptual design is
done initially using freehand sketching technique. Next, the 3D solid modeling relies
totally on the CATIA V5R19 software. Finally, a complete details drawing is produced
using CAD software. In this work, the design focuses on the blade slicing and punch bit
head to reduce the hazardous tasks during processing of the young coconut. The blade is
designed to allow the slicing movement to be maneuvered during the husk removal process.
Meanwhile, the puncher has replaced the usage of chopper in creating an opening at the top
of the endocarp. Thus, the device developed will reduce the hazardous task by eliminating
the chopping process and replacing it with the slicing process. Therefore, the tendency to
get caught in accidental injury during the chopping process can be significantly reduced.
The crab carapace is a waste which cannot be decomposed. This waste was used to
remove the Reactive Orange 16 (RO16) and Basic Blue 3 (BB3) from aqueous solution
at different operational parameters such as pH, mass load, the concentrations of dye and
the temperature. The crab collected was modified to obtain quaternized crab (QC) using
(3-chloro-2-hydroxypropyl) trimethylammonium chloride solution (C6H15Cl2NO, 65% w/w
in water). The pH of the dyes solution was varied from pH 4 to 10. The highest adsorption
percentage was achieved at pH 7 for both dyes. Increasing the QC mass for the adsorption
process had granted an increase of dyes removal percentage. The highest adsorption
percentage was achieved at 91.00% for RO16 and 29.40% for BB3 dyes with 7.5 g/L QC
used. However, the adsorption capacity of QC decreased with higher QC mass because the
dye molecules occupied on the surface and prevented other molecules to diffuse into the
QC. At higher concentration beyond 20 mg/L and 10 mg/L of RO16 and BB3, respectively,
the maximum adsorption was achieved at 2.5362 mg/g and 0.6812 mg/g. The adsorption of
both dyes by QC was best fitted using Langmuir isotherm model, explaining the adsorption
mainly occurred as a single layer on the surface of QC. Comparison to the results obtained
from the kinetic models, the adsorption was
chemisorption in nature. According to the
thermodynamic studies, the adsorption of
RO16 was an exothermic, while BB3 was
an endorthermic process.
This research was conducted to investigate the compaction performance and mechanical
strength of compacted urea fertilizer in unlubricated and lubricated die systems. The
ground urea 46% N fertilizer was compacted in a 13 mm flat-face cylindrical die set in
both unlubricated and lubricated die systems with vegetable fatty acids and magnesium
stearate as lubricants at various compaction stresses to produce urea fertilizer tablets. In
conclusion, a lubricated die system reduces the frictional effects during the production of
urea fertilizer tablets and also produces a mechanically stronger urea fertilizer tablet than
those produced in an unlubricated die system. In addition, the vegetable fatty acids and
magnesium stearate lubricants are found to improve the compaction performance of urea
fertilizer tablet as well as its mechanical strength.
Competition for limited available water for crop production is an ever-increasing issue for
farmers due to increasing demand of irrigation water worldwide. Due to high energy cost
in operating pressurized irrigation systems, energy-efficient low-pressure wick irrigation
systems can play important roles for smallholder greenhouse crop production by ensuring
higher water use efficiency than most traditional approaches. The objectives of this study
were to investigate HYDRUS 2D-simulated water distribution patterns in soil and soilless
growing media, and to evaluate water balance in these media under capillary wick irrigation
system. To accomplish these objectives, eggplants (Solanum melongena L.) were grown
in potted peatgro and sandy clay loam in a greenhouse experiment, water distribution was
simulated by using HYDRUS 2D software package and compared with the measured
values, and water uptake by the plant roots was determined for water balance calculation.
The wetting pattern was found axially symmetric in both growing media (peatgro and
soil) under the wick emitters. The simulated
water distribution in both growing media
revealed dependency of spatial extent of the
wetted zone on water application period and
hydraulic properties of the media. The mean
absolute error (MAE) in water content over
depth varied from 0.04 to 0.10 m3 m−3 and the root mean square error (RMSE) varied from 0.04 to 0.11 m3 m−3. Deviations between the
measured and simulated water contents in the peatgro medium were larger over depth than
over lateral distance. In contrast, the model criteria matched well for the sandy clay loam
and provided MAE of 0.01 to 0.02 m3 m−3 and RMSE of 0.01 to 0.03 m3 m−3, indicating
good agreement between the measured and simulated water contents.
Anaerobic composting is a promising method to fully transform food wastes into useful
materials such as biofertilizer and biogas. In this study, the optimum proportions of food
wastes containing vegetable, fruit and meat wastes with dry leaves or cow manure for
composting were determined using the simplex centroid design and response optimizer.
The effectiveness of the pilot-scale composting process was evaluated based on the targeted
compost quality of C/N ratio at 21, pH value at 8 and electrical conductivity of 1 dS/m.
Food wastes composting formulation with dry leaves suggested high percentage of dry
leaves, 86.9% with low food wastes composition of 13.1% constituted by vegetable waste
(1.1%), fruit waste (4.9%) and meat waste (7.1%). With cow manure formulation, only
6% of cow manure was recommended with
another 94.0% of food wastes contributed
by a fair mix of vegetable waste (23.2%),
fruit waste (34.3%) and meat waste (36.5%).
The developed regression models were
experimentally validated with predicted
responses obtained in acceptable ranges for
C/N ratio (21.2 - 21.8), pH (7.92 - 7.99) and
electrical conductivity (0.97 - 1.03 dS/m).
Titanium (Ti) and Ti-based alloys presence the most widely applied as advanced biomaterials
in biomedical implant applications. Moreover, these alloys are known to be the most
valuable metallic materials including spinal cord surgical treatment. It becomes an interest
due to its advantages compared to others, including its bio compatibility and corrosion
resistant. However, an issue arises when it comes for permanent implant application as
the alloy has a possible toxic effect produced from chemical reaction between body fluid
environments with alloys chemical compositions. It also relies on the performance of
neighbouring bone tissue to integrate with the implant surface. Abnormalities usually
happen when surrounding tissue shows poor responses and rejection of implants that would
leads to body inflammation. These cause an increase in foreign body reaction leading to
severe body tissue response and thus, loosening of the implant. Corrosion effects and
biocompatibility behaviour of implantation usage also become one of the reasons of
implant damage. Here, this paper reviews the importance of using Ti and Ti-based alloys
in biomedical implantation, especially in orthopaedic spinal cord injury. It also reviews the
basic aspects of corrosion effects that lead to implant mechanical damage, poor response
of body rejection and biocompatibility behaviour of implantation usage.
In this study, the effects of addition of ammonium and aluminium-based hardeners into
urea formaldehyde resin (UF) on the physico-mechanical properties and formaldehyde
emission of the rubberwood particleboard were investigated. Four types of hardeners,
namely ammonium chloride (AC), ammonium sulphate (AS), aluminium chloride (AlC)
and aluminium sulphate (AlS), were added into UF resin. The acidity, gelation time,
viscosity and free formaldehyde content of the UF/hardener mixtures were determined.
Particleboard made with the UF/hardener mixtures were tested for physico-mechanical
properties and formaldehyde emission. The pH values of the resin after addition of
aluminium-based hardeners were higher and resulted in higher viscosity and shorter
gelation time. Consequently, despite lower formaldehyde emission was recorded, the
physico-mechanical properties of the resulted particleboard were inferior compared to
that of ammonium-based hardeners. The best quality particleboard in terms of mechanical,
physical and formaldehyde emission were obtained from the particleboard made with AS,
followed by AC.
Carboxymethylcellulose (CMC) is a water-soluble polymer, which is widely used in various
fields such as food additives, textiles, pharmaceuticals and cosmetics. In this study, hydrogel
was prepared from CMC by using calcium chloride as a crosslinking agent. Optimization
of the reaction was done through investigation of four different parameters which had
different percentage of CMC (w/v), percentage of calcium chloride (w/v), reaction time and
temperature. The gel content and swelling properties of the CMC hydrogel were studied.
The highest gel content was 85.33% at 7% of CMC (w/v) with 2% of calcium chloride (w/v)
in 24 hours reaction time at room temperature. The gel content increased with the increasing
concentration of CMC and CaCl2. This was due to the higher number of functional groups
of COO- that were available in more concentrated CMC which could crosslink with CaCl2
to give higher gel content. Increasing the percentage of CaCl2 will increase the electrostatic
attraction between anionic charges of polymer chains and multivalent cation (Ca2+) that
leads to increase in ionic crosslinking of CMC. The swelling properties of CMC hydrogel
showed that the optimum degree of swelling was 45.33 (g/g). The swelling capacity of the
hydrogel in water decreased with the increase of the gel content of CMC hydrogel. This
could be due to the increase in the degree of crosslinking of the CMC hydrogel.
The continuous depletion of global oil reserves with the propensity for light distillates
propels the oil and gas industry to explore heavier fractions of crude oils with significant
amount of paraffin waxes. However, the precipitation and deposition of waxes during the
transportation of these waxy crude oils in the pipelines contribute to several issues, such as
the flowability reduction, excessive pumping cost, and wax gel formation, that adversely
affect the supposedly steady offshore oil production. As a result, substantial resources are
expended to resolve these flow assurance problems. The wax inhibitors and pour point
depressants are developed and modified to meet the wax remediation criteria. Essentially,
the wax crystals are formed through the nucleation, growth, and agglomeration processes,
while the deposition of these waxes occurs via molecular diffusion and shear dispersion.
The wax inhibitors are able to control the growth of wax crystals through nucleation, cocrystallization,
adsorption, and dispersion interactions. This paper particularly assessed
the following compounds: (1) polymeric wax inhibitors, (2) nano-hybrid pour point
depressants, (3) organic solvents, and
(4) surfactants. Given the significance of
these compounds in the deposition and
precipitation of waxes, it is imperative to
comprehensively explore the types and
nature of these compounds and their recent
applications as well as to critically assess
their strengths and drawbacks, which were
addressed in this paper. Furthermore, the
challenges of using these compounds and the factors that govern their efficiencies were also discussed. Accordingly, the carbon
length and the molecular weight of both paraffin waxes and wax inhibitors are among the
most influential factors.
Support vector machine (SVM) is one of the most popular algorithms in machine learning
and data mining. However, its reduced efficiency is usually observed for imbalanced
datasets. To improve the performance of SVM for binary imbalanced datasets, a new scheme
based on oversampling and the hybrid algorithm were introduced. Besides the use of a
single kernel function, SVM was applied with multiple kernel learning (MKL). A weighted
linear combination was defined based on the linear kernel function, radial basis function
(RBF kernel), and sigmoid kernel function for MKL. By generating the synthetic samples
in the minority class, searching the best choices of the SVM parameters and identifying
the weights of MKL by minimizing the objective function, the improved performance of
SVM was observed. To prove the strength of the proposed scheme, an experimental study,
including noisy borderline and real imbalanced datasets was conducted. SVM was applied
with linear kernel function, RBF kernel, sigmoid kernel function and MKL on all datasets.
The performance of SVM with all kernel functions was evaluated by using sensitivity,
G Mean, and F measure. A significantly improved performance of SVM with MKL was
observed by applying the proposed scheme.
Exposure to industrial air pollutants is a public health concern particularly in children due to their immaturity of respiratory systems. The distance between their school and home from the industrial area will elevate the risk of airway inflammation among children. This study aims to determine the exposure of Industrial Air Pollutants (PM10, PM2.5, NO2, SO2, and VOCs) and its association with airway inflammation (FeNO) among primary school children in industrial and non- industrial areas in Kemaman, Terengganu. A cross-sectional comparative study was conducted among Malay primary school children in Kemaman, Terengganu. A validated questionnaire was randomly distributed to children to get the background information, respiratory symptoms and exposure history of the children. The assessment of indoor air quality was carried out in each primary school and home using indoor air monitoring equipment. Fractional exhaled nitric oxide (FeNO) was measured using an NIOX MINO device. The results showed a significant difference between concentrations of PM10, PM2.5, NO2, SO2, and VOCs in different classrooms from selected schools and homes of exposed and comparative groups, P
This study compares the distribution of dissolved nutrients (NO3 − and PO4 3−) between two seasons (pre-monsoon and post-monsoon) in Pulau Perhentian, Terengganu. The concentration of dissolved PO4 3− was found to be 16 to 83 times higher during the postmonsoon period (April 2015) compared to the pre-monsoon period (October 2014). On the other hand, the concentration of dissolved NO3 − was two (2) to three (3) times higher during the post-monsoon period (April 2015) compared to the pre-monsoon period (October 2014). These nutrients’ inputs were converted from P limitation condition during the premonsoon period to N limitation condition during the post-monsoon period at our study area. The results of this study suggest that the Northeast monsoon plays an important role in influencing the distribution of dissolved nutrients between seasons in Pulau Perhentian. It is thought that during the post-monsoon period, a considerable input of nutrients from bottom water is responsible for increasing dissolved nutrients in surface water, in particular PO4 3−.