Abstract: Chalcopyrite (CuFeS2) is the most common primary
mineral used for the commercial production of copper. The low
dissolution efficiency of chalcopyrite in sulfate media has prevented
an efficient industrial leaching of this mineral in sulfate media. Ferric
ions, bacteria, oxygen and other oxidants have been used as oxidizing
agents in the leaching of chalcopyrite in sulfate and chloride media
under atmospheric or pressure leaching conditions. Two leaching
methods were studied to evaluate chalcopyrite (CuFeS2) dissolution
in acid media. First, the conventional oxidative acid leaching method
was carried out using sulfuric acid (H2SO4) and potassium
dichromate (K2Cr2O7) as oxidant at atmospheric pressure. Second,
microwave-assisted acid leaching was performed using the
microwave accelerated reaction system (MARS) for same reaction
media. Parameters affecting the copper extraction such as leaching
time, leaching temperature, concentration of H2SO4 and
concentration of K2Cr2O7 were investigated. The results of
conventional acid leaching experiments were compared to the
microwave leaching method. It was found that the copper extraction
obtained under high temperature and high concentrations of oxidant
with microwave leaching is higher than those obtained
conventionally. 81% copper extraction was obtained by the
conventional oxidative acid leaching method in 180 min, with the
concentration of 0.3 mol/L K2Cr2O7 in 0.5M H2SO4 at 50 ºC, while
93.5% copper extraction was obtained in 60 min with microwave
leaching method under same conditions.
Abstract: The purpose of this study is to determine the
relationship of anxiety level between male and female undergraduates
at a private university in Malaysia. Convenient sampling method used
in this study in which the students were selected based on the
grouping assigned by the faculty. There were 214 undergraduates
who registered the probability courses had participated in this study.
Mathematics Anxiety Rating Scale (MARS) was the instrument used
in study which used to determine students’ anxiety level towards
probability. Reliability and validity of instrument was done before the
major study was conducted. In the major study, students were given
briefing about the study conducted. Participation of this study was
voluntary. Students were given consent form to determine whether
they agree to participate in the study. Duration of two weeks was
given for students to complete the given online questionnaire. The
data collected will be analyzed using Statistical Package for the
Social Sciences (SPSS) to determine the level of anxiety. There were
three anxiety level, i.e., low, average and high. Students’ anxiety
level was determined based on their scores obtained compared with
the mean and standard deviation. If the scores obtained were below
mean and standard deviation, the anxiety level was low. If the scores
were at below and above the mean and between one standard
deviation, the anxiety level was average. If the scores were above the
mean and greater than one standard deviation, the anxiety level was
high. Results showed that both of genders were having average
anxiety level. Among low, average and high anxiety level, frequency
of males were found to be higher as compared to females. Hence, the
mean values obtained for males (M = 3.62) was higher than females
(M = 3.42). In order to be significant of anxiety level among the
gender, the p-value should be less than .05. The p-value obtained in
this study was .117. However, this value was greater than .05. Thus,
there was no significant difference of anxiety level among the gender.
In other words, there was no relationship of anxiety level with the
gender.
Abstract: Currently there are many use of threaded reinforcing
bars in construction fields because those do not need additional screw
processing when connecting reinforcing bar by threaded coupler. In
this study, reinforced concrete bridge piers using threaded rebar
coupler system at the plastic hinge area were tested to evaluate seismic
performance. The test results showed that threads of the threaded rebar
coupler system could be loosened while under tension-compression
cyclic loading because tolerance and rib face angle of a threaded rebar
coupler system are greater than that of a conventional ribbed rebar
coupler system. As a result, cracks were concentrated just outside of
the mechanical coupler and stiffness of reinforced concrete bridge pier
decreased. Therefore, it is recommended that connection ratio of
mechanical couplers in one section shall be below 50% in order that
cracks are not concentrated just outside of the mechanical coupler.
Also, reduced stiffness of the specimen should be considered when
using the threaded rebar coupler system.
Abstract: Phonocardiography is important in appraisal of
congenital heart disease and pulmonary hypertension as it reflects the
duration of right ventricular systoles. The systolic murmur in patients
with intra-cardiac shunt decreases as pulmonary hypertension
develops and may eventually disappear completely as the pulmonary
pressure reaches systemic level. Phonocardiography and auscultation
are non-invasive, low-cost, and accurate methods to assess heart
disease. In this work an objective signal processing tool to extract
information from phonocardiography signal using Wavelet is
proposed to classify the murmur as normal or abnormal. Since the
feature vector is large, a Binary Particle Swarm Optimization (PSO)
with mutation for feature selection is proposed. The extracted
features improve the classification accuracy and were tested across
various classifiers including Naïve Bayes, kNN, C4.5, and SVM.
Abstract: This paper presents modeling and simulation of
flexible robot in an underwater environment. The underwater
environment completely contrasts with ground or space environment.
The robot in an underwater situation is subjected to various dynamic
forces like buoyancy forces, hydrostatic and hydrodynamic forces.
The underwater robot is modeled as Rayleigh beam. The developed
model further allows estimating the deflection of tip in two
directions. The complete dynamics of the underwater robot is
analyzed, which is the main focus of this investigation. The control of
robot trajectory is not discussed in this paper. Simulation is
performed using Symbol Shakti software.
Abstract: An experimental investigation is carried out to
establish the performance characteristics of a compression ignition
engine while using cerium oxide nanoparticles as additive in neat
diesel and diesel-biodiesel blends. In the first phase of the
experiments, stability of neat diesel and diesel-biodiesel fuel blends
with the addition of cerium oxide nanoparticles is analyzed. After
series of experiments, it is found that the blends subjected to high
speed blending followed by ultrasonic bath stabilization improves the
stability. In the second phase, performance characteristics are studied
using the stable fuel blends in a single cylinder four stroke engine
coupled with an electrical dynamometer and a data acquisition
system. The cerium oxide acts as an oxygen donating catalyst and
provides oxygen for combustion. The activation energy of cerium
oxide acts to burn off carbon deposits within the engine cylinder at
the wall temperature and prevents the deposition of non-polar
compounds on the cylinder wall results reduction in HC emissions.
The tests revealed that cerium oxide nanoparticles can be used as
additive in diesel and diesel-biodiesel blends to improve complete
combustion of the fuel significantly.
Abstract: Crops diversity and maintaining and enhancing the
fertility of agricultural lands are basic principles of organic farming.
With a wider range of crops in agroecosystem can improve the ability
to control weeds, pests and diseases, and the performance of crops
rotation and food safety. In this sense, the main objective of the
research was to study the productivity and chemical composition of
some alternative crops and their adaptability to soil and climatic
conditions of the agricultural area in Southern Romania and to
cultivation in the organic farming system. The alternative crops were:
lentil (7 genotypes); five species of grain legumes (5 genotypes); four
species of oil crops (5 genotypes). The seed production was, on
average: 1343 kg/ha of lentil; 2500 kg/ha of field beans; 2400 kg/ha
of chick peas and blackeyed peas; more than 2000 kg/ha of atzuki
beans, over 1250 kg/ha of fenugreek; 2200 kg/ha of safflower; 570
kg/ha of oil pumpkin; 2150 kg/ha of oil flax; 1518 kg/ha of camelina.
Regarding chemical composition, lentil seeds contained: 22.18%
proteins, 3.03% lipids, 33.29% glucides, 4.00% minerals, and 259.97
kcal energy values. For field beans: 21.50% proteins, 4.40% lipids,
63.90% glucides, 5.85% minerals, 395.36 kcal energetic value. For
chick peas: 21.23% proteins, 4.55% lipids, 53.00% glucides, 3.67%
minerals, 348.22 kcal energetic value. For blackeyed peas: 23.30%
proteins, 2.10% lipids, 68.10% glucides, 3.93% minerals, 350.14 kcal
energetic value. For adzuki beans: 21.90% proteins, 2.60% lipids,
69.30% glucides, 4.10% minerals, 402.48 kcal energetic value. For
fenugreek: 21.30% proteins, 4.65% lipids, 63.83% glucides, 5.69%
minerals, 396.54 kcal energetic value. For safflower: 12.60%
proteins, 28.37% lipids, 46.41% glucides, 3.60% minerals, 505.78
kcal energetic value. For camelina: 20.29% proteins, 31.68% lipids,
36.28% glucides, 4.29% minerals, 526.63 kcal energetic value. For
oil pumpkin: 29.50% proteins, 36.92% lipids, 18.50% glucides,
5.41% minerals, 540.15 kcal energetic value. For oil flax: 22.56%
proteins, 34.10% lipids, 27.73% glucides, 5.25% minerals, 558.45
kcal energetic value.
Abstract: The synthesis of CuFe2O4 spinel powders by an
optimized combustion-like process followed by calcination is
described herein. The samples were characterized using X-ray
diffraction (XRD), differential thermal analysis (TG/DTA), scanning
electron microscopy (SEM), dilatometry and 4-probe DC methods.
Different glycine to nitrate (G/N) ratios of 1 (fuel-deficient), 1.48
(stoichiometric) and 2 (fuel-rich) were employed. Calcining the asprepared
powders at 800 and 1000°C for 5 hours showed that the G/N
ratio of 2 results in the formation of the desired copper spinel single
phase at both calcination temperatures. For G/N=1, formation of
CuFe2O4 takes place in three steps. First, iron and copper nitrates
decompose to iron oxide and pure copper. Then, copper transforms to
copper oxide and finally, copper and iron oxides react with each other
to form a copper ferrite spinel phase. The electrical conductivity and
the coefficient of thermal expansion of the sintered pelletized
samples were 2 S.cm-1 (800°C) and 11×10-6 °C-1 (25-800°C),
respectively.
Abstract: Most of the existing video streaming protocols
provide video services without considering security aspects in
decentralized mobile ad-hoc networks. The security policies adapted
to the currently existing non-streaming protocols, do not comply with
the live video streaming protocols resulting in considerable
vulnerability, high bandwidth consumption and unreliability which
cause severe security threats, low bandwidth and error prone
transmission respectively in video streaming applications. Therefore
a synergized methodology is required to reduce vulnerability and
bandwidth consumption, and enhance reliability in the video
streaming applications in MANET. To ensure the security measures
with reduced bandwidth consumption and improve reliability of the
video streaming applications, a Secure Low-bandwidth Video
Streaming through Reliable Multipath Propagation (SLVRMP)
protocol architecture has been proposed by incorporating the two
algorithms namely Secure Low-bandwidth Video Streaming
Algorithm and Reliable Secure Multipath Propagation Algorithm
using Layered Video Coding in non-overlapping zone routing
network topology. The performances of the proposed system are
compared to those of the other existing secure multipath protocols
Sec-MR, SPREAD using NS 2.34 and the simulation results show
that the performances of the proposed system get considerably
improved.
Abstract: Plants can contain a wide variety of substances with
antioxidative properties which are associated with important health
benefits. These positive health effects are of great importance at a
time when the environment is laden with many toxic substances. Five
selected herbal plants namely, Mimosa pudica, Phyllanthus niruri,
Ceiba pentandra, Eleusine polydactyla and Trema amboinensi, were
chosen for the experiment to investigate their total phenolics content
and antioxidant activities using ABTS radical cation decolorization
power, and ferric reducing antioxidant power. The total phenolic
content of each herbal plants ranges from 0.84 to 42.59 mg gallic acid
equivalent/g. The antioxidant activity in the ABTS radical cation
decolorization power varies from 0.005 to 0.362 mg trolox
equivalent/g and the FRAP ranges from 0.30 to 28.42 mg gallic acid
equivalent/g. Among the five medicinal plants, Mimosa pudica has
been an excellent performer in terms of the 3 parameters measured; it
is followed by Phyllanthus niruri. The 5 herbal plants do not have
equivalent antioxidant power. The relative high values for M. pudica
and P. niruri supports the medicinal value of both plants. The total
phenolics, ABTS and FRAP correlate strongly with one another.
Abstract: Several embryonic cellular mechanism including cell
cycle, growth and apoptosis are regulated by phosphatidylinositol-3-
kinase (PI3K)/Akt signaling pathway. The goal of present study is to
determine the effects of annatto (Bixa orellana)-derived δ-tocotrienol
(δ-TCT) on the regulations of PI3K/Akt genes in murine morula.
Twenty four 6-8 week old (23-25g) female balb/c mice were
randomly divided into four groups (G1-G4; n=6). Those groups were
subjected to the following treatments for 7 consecutive days: G1
(control) received tocopherol stripped corn oil, G2 was given 60
mg/kg/day of δ-TCT mixture (contains 90% delta & 10% gamma
isomers), G3 was given 60 mg/kg/day of pure δ-TCT (>98% purity)
and G4 received 60 mg/kg/day α-TOC. On Day 8, females were
superovulated with 5 IU Pregnant Mare’s Serum Gonadotropin
(PMSG) for 48 hours followed with 5 IU human Chorionic
Gonadotropin (hCG) before mated with males at the ratio of 1:1.
Females were sacrificed by cervical dislocation for embryo collection
48 hours post-coitum. About fifty morulas from each group were
used in the gene expression analyses using Affymetrix QuantiGene
Plex 2.0 Assay. Present data showed a significant increase (p
Abstract: A Rice Sheller is used for obtaining polished white
rice from paddy. There are about 3000 Rice Shellers in Punjab and
50000 in India. During the process of shelling lot of dust is emitted
from different unit operations like paddy silo, paddy shaker, bucket
elevators, huskers, paddy separator etc. These dust emissions have
adverse effect on the health of the workers and the wear and tear of
the shelling machinery is fast. All the dust emissions spewing out of
these unit operations of a rice Sheller were contained by providing
suitable hoods and enclosures while ensuring their workability. These
were sucked by providing an induced draft fan followed by a high
efficiency cyclone separator that has got an overall dust collection
efficiency of more than 90%. This cyclone separator replaced two
cyclone separators and a filter bag house, which the Rice Sheller was
already having. The dust concentration in the stack after the
installation of cyclone separator is well within the stipulated
standards. Besides controlling pollution, there is improvement in the
quality of products like bran and the life of shelling machinery has
enhanced. The payback period of this technology is less than four
shelling months.
Abstract: The MEMS pressure sensor has been introduced and
presented in this paper. The types of pressure sensor and its theory of
operation are also included. The latest MEMS technology, the
fabrication processes of pressure sensor are explored and discussed.
Besides, various device applications of pressure sensor such as tire
pressure-monitoring system, diesel particulate filter and others are
explained. Due to further miniaturization of the device nowadays, the
pressure sensor with nanotechnology (NEMS) is also reviewed. The
NEMS pressure sensor is expected to have better performance as well
as lower in its cost. It has gained an excellent popularity in many
applications.
Abstract: Multiple User Interference (MUI) considers the
primary problem in Optical Code-Division Multiple Access
(OCDMA), which resulting from the overlapping among the users. In
this article we aim to mitigate this problem by studying an
interference cancellation scheme called successive interference
cancellation (SIC) scheme. This scheme will be tested on two
different detection schemes, spectral amplitude coding (SAC) and
direct detection systems (DS), using partial modified prime (PMP) as
the signature codes. It was found that SIC scheme based on both SAC
and DS methods had a potential to suppress the intensity noise, that is
to say it can mitigate MUI noise. Furthermore, SIC/DS scheme
showed much lower bit error rate (BER) performance relative to
SIC/SAC scheme for different magnitude of effective power. Hence,
many more users can be supported by SIC/DS receiver system.
Abstract: This study compares the intensity of game load among
player positions and between the 1st and the 2nd half of the games.
Two guards, three forwards, and three centers (female basketball
players) participated in this study. The heart rate (HR) and its
development were monitored during two competitive games.
Statistically insignificant differences in the intensity of game load
were recorded between guards, forwards, and centers below and
above 85% of the maximal heart rate (HRmax) and in the mean HR as
% of HRmax (87.81±3.79%, 87.02±4.37%, and 88.76±3.54%,
respectively). Moreover, when the 1st and the 2nd half of the games
were compared in the mean HR (87.89±4.18% vs. 88.14±3.63% of
HRmax), no statistical significance was recorded. This information can
be useful for coaching staff, to manage and to precisely plan the
training process.
Abstract: The purpose of the present study is to find the efficacy
of high school student self-assessment of written production. It aimed
to explore the following two research questions: 1) How is topic
development of their written production improved after student
self-assessment and teacher feedback? 2) Does the consistency
between student self-assessment and teacher assessment develop after
student self-assessment and teacher feedback? The data came from the
written production of 82 Japanese high school students aged from 16
to 18 years old, an American English teacher and one Japanese English
teacher. Students were asked to write English compositions, about 150
words, for thirty minutes without using dictionaries. It was conducted
twice at intervals of two months. Students were supposed to assess
their own compositions by themselves. Teachers also assessed
students’ compositions using the same assessment sheet. The results
showed that both teachers and students assessed the second
compositions higher than the first compositions. However, there was
not the development of the consistency in coherence.
Abstract: Sound processing is one the subjects that newly
attracts a lot of researchers. It is efficient and usually less expensive
than other methods. In this paper the flow generated sound is used to
estimate the flow speed of free flows. Many sound samples are
gathered. After analyzing the data, a parameter named wave power is
chosen. For all samples the wave power is calculated and averaged
for each flow speed. A curve is fitted to the averaged data and a
correlation between the wave power and flow speed is found. Test
data are used to validate the method and errors for all test data were
under 10 percent. The speed of the flow can be estimated by
calculating the wave power of the flow generated sound and using the
proposed correlation.
Abstract: This paper presents an approach of on-line control of
the state of technosphere and environment objects based on the
integration of Data Warehouse, OLAP and Expert systems
technologies. It looks at the structure and content of data warehouse
that provides consolidation and storage of monitoring data. There is a
description of OLAP-models that provide a multidimensional
analysis of monitoring data and dynamic analysis of principal
parameters of controlled objects. The authors suggest some criteria of
emergency risk assessment using expert knowledge about danger
levels. It is demonstrated now some of the proposed solutions could
be adopted in territorial decision making support systems.
Operational control allows authorities to detect threat, prevent natural
and anthropogenic emergencies and ensure a comprehensive safety of
territory.
Abstract: Transparent nickel doped cobalt sulfide was fabricated
on a SnO2:F electrode and tested as an efficient electrocatalyst and as
an alternative to the expensive platinum counter electrode. In order to
investigate how this electrode could affect the electrical
characteristics of a dye-sensitized solar cell, we manufactured cells
with the same TiO2 photoanode sensitized with dye (N719) and
employing the same quasi-solid electrolyte, altering only the counter
electrode used. The cells were electrically and electrochemically
characterized and it was observed that the ones with the Ni doped
CoS2 outperformed the efficiency of the cells with the Pt counter
electrode (3.76% and 3.44% respectively). Particularly, the higher
efficiency of the cells with the Ni doped CoS2 counter electrode (CE)
is mainly because of the enhanced photocurrent density which is
attributed to the enhanced electrocatalytic ability of the CE and the
low charge transfer resistance at the CE/electrolyte interface.
Abstract: This contribution presents a friction estimator for
industrial purposes which identifies Coulomb friction in a steering
system. The estimator only needs a few, usually known, steering
system parameters. Friction occurs on almost every mechanical
system and has a negative influence on high-precision position
control. This is demonstrated on a steering angle controller for highly
automated driving. In this steering system the friction induces limit
cycles which cause oscillating vehicle movement when the vehicle
follows a given reference trajectory. When compensating the friction
with the introduced estimator, limit cycles can be suppressed. This
is demonstrated by measurements in a series vehicle.