Abstract: The present study was undertaken to investigate the
effect of aging parameters (time and temperature) on the mechanical
properties of Be-and/or Zr- treated 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 containing Be and/or Zr. Different aging
treatment were carried out for the as solution treated (SHT)
specimens (after quenching in warm water). The specimens were
aged at different conditions; Natural and artificial aging was carried
out at room temperature, 120C, 150C, 180C and 220C for different
periods of time. Duplex 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 data results as a function of different aging parameters are
analysed. A statistical design of experiments (DOE) approach using
fractional factorial design is applied to acquire an understanding of
the effects of these variables and their interactions on the mechanical
properties of Be- and/or Zr- treated 7075 alloys. Mathematical
models are developed to relate the alloy mechanical properties with
the different aging parameters.
Abstract: This study concerned the dynamic behavior of the
wind turbine rotor. Before all we have studied the loads applied to the
rotor, which allows the knowledge their effect on the fatigue, also
studied the rotor with longitudinal crack in order to determine stress,
strain and displacement. Firstly we compared the first six modes
shapes between cracking and uncracking of HAWT rotor. Secondly
we show show evolution of first six natural frequencies with
longitudinal crack propagation. Finally we conclude that the residual
change in the natural frequencies can be used as in shaft crack
diagnosis predictive maintenance.
Abstract: Speech enhancement is a long standing problem with
numerous applications like teleconferencing, VoIP, hearing aids and
speech recognition. The motivation behind this research work is to
obtain a clean speech signal of higher quality by applying the optimal
noise cancellation technique. Real-time adaptive filtering algorithms
seem to be the best candidate among all categories of the speech
enhancement methods. In this paper, we propose a speech
enhancement method based on Recursive Least Squares (RLS)
adaptive filter of speech signals. Experiments were performed on
noisy data which was prepared by adding AWGN, Babble and Pink
noise to clean speech samples at -5dB, 0dB, 5dB and 10dB SNR
levels. We then compare the noise cancellation performance of
proposed RLS algorithm with existing NLMS algorithm in terms of
Mean Squared Error (MSE), Signal to Noise ratio (SNR) and SNR
Loss. Based on the performance evaluation, the proposed RLS
algorithm was found to be a better optimal noise cancellation
technique for speech signals.
Abstract: The Standard Penetration Test (SPT) is the most
common in situ test for soil investigations. On the other hand, the
Cone Penetration Test (CPT) is considered one of the best
investigation tools. Due to the fast and accurate results that can be
obtained it complaints the SPT in many applications like field
explorations, design parameters, and quality control assessments.
Many soil index and engineering properties have been correlated to
both of SPT and CPT. Various foundation design methods were
developed based on the outcome of these tests. Therefore it is vital to
correlate these tests to each other so that either one of the tests can be
used in the absence of the other, especially for preliminary evaluation
and design purposes.
The primary purpose of this study was to investigate the
relationships between the SPT and CPT for different type of sandy
soils in Florida. Data for this research were collected from number of
projects sponsored by the Florida Department of Transportation
(FDOT), six sites served as the subject of SPT-CPT correlations. The
correlations were established between the cone resistance (qc), sleeve
friction (fs) and the uncorrected SPT blow counts (N) for various
soils.
A positive linear relationship was found between qc, fs and N for
various sandy soils. In general, qc versus N showed higher
correlation coefficients than fs versus N. qc/N ratios were developed
for different soil types and compared to literature values, the results
of this research revealed higher ratios than literature values.
Abstract: Numeracy, like Literacy is considered to be a core
value of modern societies. Most higher education institutions in
South Africa include being numerate as an important graduate
attribute. It is argued that a suitability numerate society contributes to
social justice, empowerment, financial and environmental
sustainability and a lack of numeracy practices can contribute to
disempowerment.
Numeracy is commonly misconstrued as a basic and simple
practice, similar in nature to basic arithmetic. This study highlights
the complexities of higher education numeracy practices by analyzing
a programme in a higher education institution in South Africa using
the New Literacies Studies perspective.
Abstract: The industrial process adds to engineering wood
products features absent in solid wood, with homogeneous structure
and reduced defects, improved physical and mechanical properties,
bio-deterioration, resistance and better dimensional stability,
improving quality and increasing the reliability of structures wood.
These features combined with using fast-growing trees, make them
environmentally ecological products, ensuring a strong consumer
market. The wood I-joists are manufactured by the industrial profiles
bonding flange and web, an important aspect of the production of
wooden I-beams is the adhesive joint that bonds the web to the
flange. Adhesives can effectively transfer and distribute stresses,
thereby increasing the strength and stiffness of the composite. The
objective of this study is to evaluate different resins in a shear strain
specimens with the aim of analyzing the most efficient resin and
possibility of using national products, reducing the manufacturing
cost. First was conducted a literature review, where established the
geometry and materials generally used, then established and analyzed
8 national resins and produced six specimens for each.
Abstract: Iran has several potential for using renewable
energies, so use them could significantly contribute to energy supply.
The purpose of this paper is to identify the potential of the country
and select the appropriate DG technologies with consideration the
potential and primary energy resources in the regions. In this context,
hybrid energy systems proportionate with the potential of different
regions will be determined based on technical, economic, and
environmental aspect. In the following the proposed structure will be
optimized in terms of size and cost. DG technologies used in this
project include photovoltaic system, wind turbine, diesel generator
and battery bank. The HOMER software is applied for choosing the
appropriate structure and the optimization of system sizing. The
results have been analyzed in terms of technical and economic. The
performance and the cost of each project demonstrate the appropriate
structure of hybrid energy system in that region.
Abstract: The tombolo of Giens is located in the town of Hyères
(France). We recall the history of coastal erosion, and prominent
factors affecting the evolution of the western tombolo. We then
discuss the possibility of stabilizing the western tombolo. Our
argumentation relies on a coupled model integrating swells, currents,
water levels and sediment transport. We present the conclusions of
the simulations of various scenarios, including pre-existing
propositions from coastal engineering offices. We conclude that
beach replenishment seems to be necessary but not sufficient for the
stabilization of the beach. Breakwaters reveal effective particularly in
the most exposed northern area. Some solutions fulfill conditions so
as to be elected as satisfactory. We give a comparative analysis of the
efficiency of 14 alternatives for the protection of the tombolo.
Abstract: The use of technology in the classroom is an issue that
is constantly evolving. Digital age students learn differently than their
teachers did, so now the teacher should be constantly evolving their
methods and teaching techniques to be more in touch with the
student. In this paper a case study presents how were used some of
these technologies by accompanying a classroom course, this in order
to provide students with a different and innovative experience as their
teacher usually presented the activities to develop. As students
worked in the various activities, they increased their digital skills by
employing unknown tools that helped them in their professional
training. The twenty-first century teacher should consider the use of
Information and Communication Technologies in the classroom
thinking in skills that students of the digital age should possess. It
also takes a brief look at the history of distance education and it is
also highlighted the importance of integrating technology as part of
the student's training.
Abstract: Physical properties of uranium dinitride (UN2) were
investigated in detail using first principle calculations based on
density functional theory (DFT). To study the strong correlation
effects due to 5f uranium valence electrons, the on-site coulomb
interaction correction U via the Hubbard-like term (DFT+U) was
employed. The UN2 structural, mechanical and thermodynamic
properties were calculated within DFT and Various U of DFT+U
approach.
The Perdew–Burke–Ernzerhof (PBE.5.2) version of the
generalized gradient approximation (GGA) is used to describe the
exchange-correlation with the projector-augmented wave (PAW)
pseudo potentials.
A comparative study shows that results are improved by using the
Hubbard formalism for a certain U value correction like the structural
parameter. For some physical properties the variation versus
Hubbard-U is strong like Young modulus but for others it is weakly
noticeable such as bulk modulus.
We noticed also that from U=7.5 eV, elastic results don’t agree
with the cubic cell because of the C44 values which turn out to be
negative.
Abstract: A novel hybrid model of the lumbar spine, allowing
fast static and dynamic simulations of the disc pressure
and the spine mobility, is introduced in this work. Our
contribution is to combine rigid bodies, deformable finite
elements, articular constraints, and springs into a unique model
of the spine. Each vertebra is represented by a rigid body
controlling a surface mesh to model contacts on the facet
joints and the spinous process. The discs are modeled using
a heterogeneous tetrahedral finite element model. The facet
joints are represented as elastic joints with six degrees of
freedom, while the ligaments are modeled using non-linear
one-dimensional elastic elements. The challenge we tackle
is to make these different models efficiently interact while
respecting the principles of Anatomy and Mechanics.
The mobility, the intradiscal pressure, the facet joint force and
the instantaneous center of rotation of the lumbar spine are
validated against the experimental and theoretical results of
the literature on flexion, extension, lateral bending as well as
axial rotation.
Our hybrid model greatly simplifies the modeling task and
dramatically accelerates the simulation of pressure within the
discs, as well as the evaluation of the range of motion and the
instantaneous centers of rotation, without penalizing precision.
These results suggest that for some types of biomechanical
simulations, simplified models allow far easier modeling and
faster simulations compared to usual full-FEM approaches
without any loss of accuracy.
Abstract: The purpose of this study is to forecast the influences
of information and communication technology (ICT) on the structural
changes of Japanese economies. In this study, input-output (IO) and
statistical approaches are used as analysis instruments. More
specifically, this study employs Leontief IO coefficients and
constrained multivariate regression (CMR) model in order to achieve
the purpose. The periods of initial and forecast in this study are 2005
and 2015, respectively. In this study, ICT is represented by ICT capital
stocks. This study conducts two levels of analysis, namely macro and
micro. The results of macro level analysis show that the dynamics of
Japanese economies on the forecast period, relative to the initial period,
are not so high. We focus on (1) commerce, (2) business services and
office supplies, and (3) personal services sectors when conducting the
analysis of the micro level. Further, we analyze its specific IO
coefficients when doing this analysis. The results of the analysis
explain that ICT gives a strong influence on the changes of these
coefficients from initial to forecast periods.
Abstract: The aim of this paper is to give an assessment of
environmental effects of IPPC permit conditions of installations that
are in specific territory with high concentration of industrial
activities.
The IPPC permit is the permit that each operator should hold to
operate the installation as stated by the directive 2010/75/UE on
industrial emissions (integrated pollution prevention and control),
known as IED (Industrial Emissions Directive).
The IPPC permit includes all the measures necessary to achieve a
high level of protection of the environment as a whole, also defining
the monitoring requirements as measurement methodology,
frequency and evaluation procedure. The emissions monitoring of a
specific plant may also give indications of the contribution of these
emissions on the air quality of a definite area.
So, it is clear that the IPPC permits are important tools both to
improve the environmental framework and to achieve the air quality
standards, assisting to assess the possible industrial sources
contributions to air pollution.
Abstract: The present paper summarizes the analysis of the
request for consultation of information and data on industrial
emissions made publicly available on the web site of the Ministry of
Environment, Land and Sea on integrated pollution prevention and
control from large industrial installations, the so called “AIA Portal”.
As a matter of fact, a huge amount of information on national
industrial plants is already available on internet, although it is usually
proposed as textual documentation or images.
Thus, it is not possible to access all the relevant information
through interoperability systems and also to retrieval relevant
information for decision making purposes as well as rising of
awareness on environmental issue.
Moreover, since in Italy the number of institutional and private
subjects involved in the management of the public information on
industrial emissions is substantial, the access to the information is
provided on internet web sites according to different criteria; thus, at
present it is not structurally homogeneous and comparable.
To overcome the mentioned difficulties in the case of the
Coordinating Committee for the implementation of the Agreement
for the industrial area in Taranto and Statte, operating before the
IPPC permit granting procedures of the relevant installation located
in the area, a big effort was devoted to elaborate and to validate data
and information on characterization of soil, ground water aquifer and
coastal sea at disposal of different subjects to derive a global
perspective for decision making purposes. Thus, the present paper
also focuses on main outcomes matured during such experience.
Abstract: Collaborative technologies or software known as
groupware are key enabling tools for communication, collaboration
and co-ordination among individuals, work groups and businesses.
Available reviews of the groupware literature are very few,
and mostly neither systematic nor recent.
This paper is an effort to fill this gap, and to provide researchers,
with a more up-to-date and wide systematic literature review. For this
purpose, 1087 scholarly articles, published from 1990 to 2013, on the
topic of groupware, were collected by the literature search. The study
here adopted the systematic approach of lexical analysis for the
analysis of those articles.
Abstract: Verification and Validation of Simulated Process
Model is the most important phase of the simulator life cycle.
Evaluation of simulated process models based on Verification and
Validation techniques checks the closeness of each component model
(in a simulated network) with the real system/process with respect to
dynamic behaviour under steady state and transient conditions. The
process of Verification and Validation helps in qualifying the process
simulator for the intended purpose whether it is for providing
comprehensive training or design verification. In general, model
verification is carried out by comparison of simulated component
characteristics with the original requirement to ensure that each step
in the model development process completely incorporates all the
design requirements. Validation testing is performed by comparing
the simulated process parameters to the actual plant process
parameters either in standalone mode or integrated mode.
A Full Scope Replica Operator Training Simulator for PFBR -
Prototype Fast Breeder Reactor has been developed at IGCAR,
Kalpakkam, INDIA named KALBR-SIM (Kalpakkam Breeder
Reactor Simulator) where in the main participants are
engineers/experts belonging to Modeling Team, Process Design and
Instrumentation & Control design team. This paper discusses about
the Verification and Validation process in general, the evaluation
procedure adopted for PFBR operator training Simulator, the
methodology followed for verifying the models, the reference
documents and standards used etc. It details out the importance of
internal validation by design experts, subsequent validation by
external agency consisting of experts from various fields, model
improvement by tuning based on expert’s comments, final
qualification of the simulator for the intended purpose and the
difficulties faced while co-coordinating various activities.
Abstract: Polysulfone (PSU) is a specialty engineering polymer
having various industrial applications. PSU is especially used in
waste water treatment membranes due to its good mechanical
properties, structural and chemical stability. But it is a hydrophobic
material and therefore its surface aim to pollute easily. In order to
resolve this problem and extend the properties of membrane, PSU
surface is rendered hydrophilic by addition of the sepiolite
nanofibers. Sepiolite is one of the natural clays, which is a hydrate
magnesium silicate fiber, also one of the well known layered clays of
the montmorillonites where has several unique channels and pores
within. It has also moisture durability, strength and low price.
Sepiolite channels give great capacity of absorption and good surface
properties. In this study, nanocomposites of commercial PSU and
Sepiolite were prepared by solvent mixing method. Different organic
solvents and their mixtures were used. Rheological characteristics of
PSU-Sepiolite solvent mixtures were analyzed, the solubility of
nanocomposite content in those mixtures were studied.
Abstract: The design and plantwide control of an integrated
plant where the endothermic 1,4-butanediol dehydrogenation and the
exothermic furfural hydrogenation is simultaneously performed in a
single reactor is studied. The reactions can be carried out in an
adiabatic reactor using small hydrogen excess and with reduced
parameter sensitivity. The plant is robust and flexible enough to
allow different production rates of γ-butyrolactone and 2-methyl
furan, keeping high product purities. Rigorous steady state and
dynamic simulations performed in AspenPlus and AspenDynamics to
support the conclusions.
Abstract: Malaysia is rich with historic buildings, particularly in
Penang and Malacca states. Restoration activities are increasingly
important as these states are recognized under UNESCO World
Heritage Sites. Restoration activities help to maintain the uniqueness
and value of a heritage building. However, increasing in restoration
activities has resulted in large quantities of waste. To cope with this
problem, the 3R concept (reduce, reuse and recycle) is introduced.
The 3R concept is one of the waste management hierarchies. This
concept is still yet to apply in the building restoration industry
compared to the construction industry. Therefore, this study aims to
promote the 3R concept in the heritage building restoration industry.
This study aims to examine the importance of 3R concept and to
identify challenges in applying the 3R concept in the heritage
building restoration industry. This study focused on contractors and
consultants who are involved in heritage restoration projects in
Penang. Literature review and interviews helps to reach the research
objective. Data that obtained is analyzed by using content analysis.
For the research, application of 3R concept is important to conserve
natural resources and reduce pollution problems. However, limited
space to organise waste is the obstruction during the implementation
of this concept. In conclusion, the 3R concept plays an important role
in promoting environmental conservation and helping in reducing the
construction waste.
Abstract: This work presents synthesis of α,ω-dithienyl
terminated poly(ethylene glycol) (PEGTh) capable for further chain
extension by either chemical or electrochemical polymeriztion.
PEGTh was characterized by FTIR and 1H-NMR. Further
copolymerization of PEGTh and pyrrole (Py) was performed by
chemical oxidative polymerization using ceric (IV) salt as an oxidant
(PPy-PEGTh). PEG without end group modification was used
directly to prepare copolymers with Py by Ce (IV) salt (PPy-PEG).
Block copolymers with mole ratio of pyrrole to PEGTh (PEG) 50:1
and 10:1 were synthesized. The electrical conductivities of
copolymers PPy-PEGTh and PPy-PEG were determined by four
point probe technique. Influence of the synthetic route and content of
the insulating segment on conductivity and yield of the copolymers
were investigated.