Abstract: A study was carried out to determine the effect of water quality on flotation performance. The experimental test work comprised of batch flotation tests using Denver lab cell for a period of 10 minutes. Nine different test runs were carried out in triplicates to ensure reproducibility using different water types from different thickener overflows, return and sewage effluent water (process water) and portable water. The water sources differed in pH, total dissolved solids, total suspended solids and conductivity. Process water was found to reduce the concentrate recovery and mass pull, while portable water increased the concentrate recovery and mass pull. Portable water reduced the concentrate grade while process water increased the concentrate grade. It is proposed that a combination of process water and portable water supply be used in flotation circuits to balance the different effects that the different water types have on the flotation efficiency.
Abstract: Even though most researchers would agree that in
symbiotic relationships, like the one between parent and child,
influences become reciprocal over time, empirical evidence
supporting this claim is limited. The aim of the current study was to
develop and test a model describing the reciprocal influence between
characteristics of the parent-child relationship, such as closeness and
conflict, and the child-s bullying and victimization experiences at
school. The study used data from the longitudinal Study of Early
Child-Care, conducted by the National Institute of Child Health and
Human Development. The participants were dyads of early
adolescents (5th and 6th graders during the two data collection waves)
and their mothers (N=1364). Supporting our hypothesis, the findings
suggested a reciprocal association between bullying and positive
parenting, although this association was only significant for boys.
Victimization and positive parenting were not significantly
interrelated.
Abstract: The Requirements Abstraction Model (RAM) helps in managing abstraction in requirements by organizing them at four levels (product, feature, function and component). The RAM is adaptable and can be tailored to meet the needs of the various organizations. Because software requirements are an important source of information for developing high-level tests, organizations willing to adopt the RAM model need to know the suitability of the RAM requirements for developing high-level tests. To investigate this suitability, test cases from twenty randomly selected requirements were developed, analyzed and graded. Requirements were selected from the requirements document of a Course Management System, a web based software system that supports teachers and students in performing course related tasks. This paper describes the results of the requirements document analysis. The results show that requirements at lower levels in the RAM are suitable for developing executable tests whereas it is hard to develop from requirements at higher levels.
Abstract: In this article the investigation about installation heat
recovery steam generation (HRSG) on the exhaust of turbo generators of phases 2&3 at South Pars Gas Complex is presented.
The temperature of exhaust gas is approximately 665 degree centigrade, Installation of heat recovery boiler was simulated in
ThermoFlow 17.0.2 software, based on test operation data and the
equipments site operation conditions in Pars exclusive economical energy area, the affect of installation HRSG package on the available
gas turbine and its operation parameters, ambient temperature, the
exhaust temperatures steam flow rate were investigated. Base on the results recommended HRSG package should have the capacity for 98
ton per hour high pressure steam generation this refinery, by use of
exhaust of three gas turbines for each package in operation condition of each refinery at 30 degree centigrade. Besides saving energy this
project will be an Environment-Friendly project. The Payback Period
is estimated approximately 1.8 year, with considering Clean Development Mechanism.
Abstract: The oleaginous yeasts Lipomyces starkey were grown
in the presence of dairy industry wastewaters (DIW). The yeasts were
able to degrade the organic components of DIW and to produce a
significant fraction of their biomass as triglycerides.
When using DIW from the Ricotta cheese production or residual
whey as growth medium, the L. starkey could be cultured without
dilution nor external organic supplement. On the contrary, the yeasts
could only partially degrade the DIW from the Mozzarella cheese
production, due to the accumulation of a metabolic product beyond
the threshold of toxicity. In this case, a dilution of the DIW was
required to obtain a more efficient degradation of the carbon
compounds and an higher yield in oleaginous biomass.
The fatty acid distribution of the microbial oils obtained showed a
prevalence of oleic acid, and is compatible with the production of a II
generation biodiesel offering a good resistance to oxidation as well as
an excellent cold-performance.
Abstract: The most influential programming paradigm today
is object oriented (OO) programming and it is widely used in
education and industry. Recognizing the importance of equipping
students with OO knowledge and skills, it is not surprising that most
Computer Science degree programs offer OO-related courses. How
do we assess whether the students have acquired the right objectoriented
skills after they have completed their OO courses? What are
object oriented skills? Currently none of the current assessment
techniques would be able to provide this answer. Traditional forms of
OO programming assessment provide a ways for assigning numerical
scores to determine letter grades. But this rarely reveals information
about how students actually understand OO concept. It appears
reasonable that a better understanding of how to define and assess
OO skills is needed by developing a criterion referenced model. It is
even critical in the context of Malaysia where there is currently a
growing concern over the level of competency of Malaysian IT
graduates in object oriented programming. This paper discussed the
approach used to develop the criterion-referenced assessment model.
The model can serve as a guideline when conducting OO
programming assessment as mentioned. The proposed model is
derived by using Goal Questions Metrics methodology, which helps
formulate the metrics of interest. It concluded with a few suggestions
for further study.
Abstract: An effort to develop a unit commitment approach
capable of handling large power systems consisting of both thermal
and hydro generating units offers a large profitable return. In order to
be feasible, the method to be developed must be flexible, efficient
and reliable. In this paper, various proposed methods have been
described along with their strengths and weaknesses. As all of these
methods have some sort of weaknesses, a comprehensive algorithm
that combines the strengths of different methods and overcomes each
other-s weaknesses would be a suitable approach for solving
industry-grade unit commitment problem.
Abstract: This study investigated the effect of oxygen and
micro-cracking on the flotation of low grade nickel sulphide ore. The
ore treated contained serpentine minerals which have a history of
being difficult to process efficiently. The use of oxygen as a bubbling
gas has been noted to be effective because it increases the pulp
potential. The desired effect of micro cracking the ore is that the
nickel sulphide minerals will become activated and this activation
will render these minerals more susceptible to react with potassium
amyl xanthate collectors, resulting in a higher recovery of nickel and
hinder the recovery of other undesired minerals contained in the ore.
Higher nickel recoveries were obtained when pure oxygen was used
as a bubbling gas rather than the conventional air. Microwave
cracking favored the recovery of nickel.
Abstract: The main purpose of this research aimed to create tactile texture designed media for the blind used for extra learning outside classrooms in order to enhance imagination of the blind about Himmapan creatures, furthermore, the main objective of the research focused on improving the visual disabled perception to be equal to normal people. The target group of the research is blinded students studying in The Bangkok school for the blind between grade 4-6 in the second semester of 2011 who are able to read the braille language. The research methodology consisted of the field study and the documentary study related to the blind, tactile texture designed media and Himmapan creatures. 10 pictures of tactile texture designed media were created in the designing process which began after the analysis had conducted based the primary and secondary data. The works had presented to experts in the visual disabled field who evaluated the works. After approval, the works used as prototype to teach the blind. KeywordsBlind, Himmapan Creatures, Tactile Texture.
Abstract: The studies concerned an effect of six variants of ion
exchange substrate (nutrient carriers with a different potential impact
on pH of soil solution) on vegetation of orchard grass during two
different periods (42 and 84 days). In the pot experiment plants were
grown on sand (model of degraded soil) and six mixtures of sand and
2% (v/v) additions of particular variants of ion exchange substrate
(with pH ranged from 5.5 to 8.0). The study results showed that the
addition of the substrate at pH=6.5 caused the highest increase in
plant yield after shorter vegetation period whereas the addition of the
substrate at pH=5.5 increased dry stem and root biomass of orchard
grass after longer vegetation period. Thus, the ion exchange substrate
at pH=6.5 can be recommended for restoration of exhausted soils
when shorter vegetation period is planned; the ion exchange substrate
at pH=5.5 can be used for the same purpose when longer periods of
vegetative growth are considered.
Abstract: In this paper, a Gaussian multiple input multiple output multiple eavesdropper (MIMOME) channel is considered where a transmitter communicates to a receiver in the presence of an eavesdropper. We present a technique for determining the secrecy capacity of the multiple input multiple output (MIMO) channel under Gaussian noise. We transform the degraded MIMOME channel into multiple single input multiple output (SIMO) Gaussian wire-tap channels and then use scalar approach to convert it into two equivalent multiple input single output (MISO) channels. The secrecy capacity model is then developed for the condition where the channel state information (CSI) for main channel only is known to the transmitter. The results show that the secret communication is possible when the eavesdropper channel noise is greater than a cutoff noise level. The outage probability is also analyzed of secrecy capacity is also analyzed. The effect of fading and outage probability is also analyzed.
Abstract: Utilization of waste material in asphalt pavement
would be beneficial in order to find an alternative solution to increase
service life of asphalt pavement and reduce environmental pollution
as well. One of these waste materials is Polyethylene Terephthalate
(PET) which is a type of polyester material and is produced in a large
extent. This research program is investigating the effects of adding
waste PET particles into the asphalt mixture with a maximum size of
2.36 mm. Different percentages of PET were added into the mixture
during dry process. Gap-graded mixture (SMA 14) and PG 80-100
asphalt binder have been used for this study. To evaluate PET
reinforced asphalt mixture different laboratory investigations have
been conducted on specimens. Marshall Stability test was carried
out. Besides, stiffness modulus test and indirect tensile fatigue test
were conducted on specimens at optimum asphalt content. It was
observed that in many cases PET reinforced SMA mixture had better
mechanical properties in comparison with control mixture.
Abstract: Study of the vibration cylindrical shells made of
a functionally gradient material (FGM) composed of stainless
steel and nickel is important. Material properties are graded in
the thickness direction of the shell according to volume
fraction power law distribution. The objective is to study the
natural frequencies, the influence of constituent volume
fractions and the effects of boundary conditions on the natural
frequencies of the FG cylindrical shell. The study is carried
out using third order shear deformation shell theory. The
governing equations of motion of FG cylindrical shells are
derived based on shear deformation theory. Results are
presented on the frequency characteristics, influence of
constituent volume fractions and the effects of clampedclamped
boundary conditions.
Abstract: In this paper we compare the accuracy of data mining
methods to classifying students in order to predicting student-s class
grade. These predictions are more useful for identifying weak
students and assisting management to take remedial measures at early
stages to produce excellent graduate that will graduate at least with
second class upper. Firstly we examine single classifiers accuracy on
our data set and choose the best one and then ensembles it with a
weak classifier to produce simple voting method. We present results
show that combining different classifiers outperformed other single
classifiers for predicting student performance.
Abstract: The use of new technologies such internet (e-mail, chat
rooms) and cell phones has steeply increased in recent years.
Especially among children and young people, use of technological
tools and equipments is widespread. Although many teachers and
administrators now recognize the problem of school bullying, few are
aware that students are being harassed through electronic
communication. Referred to as electronic bullying, cyber bullying, or
online social cruelty, this phenomenon includes bullying through email,
instant messaging, in a chat room, on a website, or through
digital messages or images sent to a cell phone. Cyber bullying is
defined as causing deliberate/intentional harm to others using internet
or other digital technologies. It has a quantitative research design nd
uses relational survey as its method. The participants consisted of
300 secondary school students in the city of Konya, Turkey. 195
(64.8%) participants were female and 105 (35.2%) were male. 39
(13%) students were at grade 1, 187 (62.1%) were at grade 2 and 74
(24.6%) were at grade 3. The “Cyber Bullying Question List"
developed by Ar─▒cak (2009) was given to students. Following
questions about demographics, a functional definition of cyber
bullying was provided. In order to specify students- human values,
“Human Values Scale (HVS)" developed by Dilmaç (2007) for
secondary school students was administered. The scale consists of 42
items in six dimensions. Data analysis was conducted by the primary
investigator of the study using SPSS 14.00 statistical analysis
software. Descriptive statistics were calculated for the analysis of
students- cyber bullying behaviour and simple regression analysis was
conducted in order to test whether each value in the scale could
explain cyber bullying behaviour.
Abstract: In the present work, study of the vibration of thin cylindrical shells made of a functionally gradient material (FGM) composed of stainless steel and nickel is presented. Material properties are graded in the thickness direction of the shell according to volume fraction power law distribution. The objective is to study the natural frequencies, the influence of constituent volume fractions and the effects of boundary conditions on the natural frequencies of the FG cylindrical shell. The study is carried out using third order shear deformation shell theory. The analysis is carried out using Hamilton's principle. The governing equations of motion of FG cylindrical shells are derived based on shear deformation theory. Results are presented on the frequency characteristics, influence of constituent volume fractions and the effects of clamped-free boundary conditions
Abstract: The purpose of this study is to investigate the effects
of modality principles in instructional software among first grade
pupils- achievements in the learning of Arabic Language. Two modes
of instructional software were systematically designed and
developed, audio with images (AI), and text with images (TI). The
quasi-experimental design was used in the study. The sample
consisted of 123 male and female pupils from IRBED Education
Directorate, Jordan. The pupils were randomly assigned to any one of
the two modes. The independent variable comprised the two modes
of the instructional software, the students- achievement levels in the
Arabic Language class and gender. The dependent variable was the
achievements of the pupils in the Arabic Language test. The
theoretical framework of this study was based on Mayer-s Cognitive
Theory of Multimedia Learning. Four hypotheses were postulated
and tested. Analyses of Variance (ANOVA) showed that pupils using
the (AI) mode performed significantly better than those using (TI)
mode. This study concluded that the audio with images mode was an
important aid to learning as compared to text with images mode.
Abstract: The purpose of this study is to determine the
circumstances affecting elementary school students in their family
and school lives and what kind of emotions children may feel
because of these circumstances. The study was carried out according
to the survey model. Four Turkish elementary schools provided 123
fourth grade students for participation in the study. The study-s data
were collected by using worksheets for the activity titled “Important
Days in Our Lives", which was part of the Elementary School Social
Sciences Course 4th Grade Education Program. Data analysis was
carried out according to the content analysis technique used in
qualitative research. The study detected that circumstances of their
family and school lives caused children to feel emotions such as
happiness, sadness, anger, fear and jealousy. The circumstances and
the emotions caused by these circumstances were analyzed according
to gender and interpreted by presenting them with their frequencies.
Abstract: Basic ingredients of concrete are cement, fine aggregate, coarse aggregate and water. To produce a concrete of certain specific properties, optimum proportion of these ingredients are mixed. The important factors which govern the mix design are grade of concrete, type of cement and size, shape and grading of aggregates. Concrete mix design method is based on experimentally evolved empirical relationship between the factors in the choice of mix design. Basic draw backs of this method are that it does not produce desired strength, calculations are cumbersome and a number of tables are to be referred for arriving at trial mix proportion moreover, the variation in attainment of desired strength is uncertain below the target strength and may even fail. To solve this problem, a lot of cubes of standard grades were prepared and attained 28 days strength determined for different combination of cement, fine aggregate, coarse aggregate and water. An artificial neural network (ANN) was prepared using these data. The input of ANN were grade of concrete, type of cement, size, shape and grading of aggregates and output were proportions of various ingredients. With the help of these inputs and outputs, ANN was trained using feed forward back proportion model. Finally trained ANN was validated, it was seen that it gave the result with/ error of maximum 4 to 5%. Hence, specific type of concrete can be prepared from given material properties and proportions of these materials can be quickly evaluated using the proposed ANN.
Abstract: The present study was conducted to investigate the
response of plants exposed to lignite-based thermal power plant
emission. For this purpose, five plant species were collected from 1.0
km distance (polluted site) and control plants were collected from
20.0 km distance (control site) to thermal power plant. The common
tree species Cassia siamea Lamk., Polyalthia longifolia. Sonn,
Acacia longifolia (Andrews) Wild., Azadirachta indica A.Juss, Ficus
religiosa L. were selected as test plants. Photosynthetic pigments
changes (chlorophyll a, chlorophyll b and carotenoids) and rubisco
enzyme modifications were studied. Reduction was observed in the
photosynthetic pigments of plants growing in polluted site and also
large sub unit of the rubisco enzyme was degraded in Azadirachta
indica A. Juss collected from polluted site.