Abstract: The seismic feedback experiences in Algeria have
shown higher percentage of damages for non-code conforming
reinforced concrete (RC) buildings. Furthermore, the vulnerability of
these buildings was further aggravated due to presence of many
factors (e.g. weak the seismic capacity of these buildings, shorts
columns, Pounding effect, etc.).
Consequently Seismic risk assessments were carried out on
populations of buildings to identify the buildings most likely to
undergo losses during an earthquake. The results of such studies are
important in the mitigation of losses under future seismic events as
they allow strengthening intervention and disaster management plans
to be drawn up.
Within this paper, the state of the existing structures is assessed using
"the vulnerability index" method. This method allows the
classification of RC constructions taking into account both, structural
and non structural parameters, considered to be ones of the main
parameters governing the vulnerability of the structure. Based on
seismic feedback from past earthquakes DPM (damage probability
matrices) were developed too.
Abstract: A reliable estimate of the average bond stress within
the anchorage of steel reinforcing bars in tension is critically
important for the design of reinforced concrete member. This paper
describes part of a recently completed experimental research program
in the Centre for Infrastructure Engineering and Safety (CIES) at the
University of New South Wales, Sydney, Australia aimed at
assessing the effects of different factors on the anchorage
requirements of modern high strength steel reinforcing bars. The
study found that an increase in the anchorage length and bar diameter
generally leads to a reduction of the average ultimate bond stress. By
the extension of a well established analytical model of bond and
anchorage, it is shown here that the differences in the average
ultimate bond stress for different anchorage lengths is associated with
the variable degree of plastic deformation in the tensile zone of the
concrete surrounding the bar.
Abstract: Low carbon deep drawing steel DC 01 according to EN 10130-91 was nitrooxidized in dissociated ammonia at 580°C/45 min and consequently oxidised at 380°C/5 min in vapour of distilled water. Material after nitrooxidation had 54 % increase of yield point, 34 % increase of strength and 10-times increased resistance to atmospheric corrosion in comparison to the material before nitrooxidation. The microstructure of treated material consisted of thin ε-phase layer connected to layer containing precipitated massive needle shaped Fe4N - γ' nitrides. This layer passed to a diffusion layer consisting of fine irregular shaped Fe16N2 - α'' nitrides regularly dispersed in ferritic matrix. Fatigue properties were examined under bending load with frequency of 20 kHz and sinusoidal symmetric cycle. The results confirmed positive influence of nitrooxidation on fatigue properties as fatigue limit of treated material was double in comparison to untreated material.
Abstract: This paper presents a solution for ceramic cutting tools availability in interrupted machining. Experiments were performed on a special fixture – the interrupted cut simulator. This fixture was constructed at our Department of Machining and Assembly within the scope of a project by the Czech Science Foundation. The goals of the tests were to contribute to the wider usage of these cutting materials in machining, especially in interrupted machining. Through the centuries, producers of ceramic cutting tools have taken big steps forward. Namely, increasing durability in maintaining high levels of strength and hardness lends an advantage. Some producers of these materials advise cutting inserts for interrupted machining at the present time [1, 2].
Abstract: Adolescents in Northern Uganda are at risk of teenage
pregnancies, unsafe abortions and sexually transmitted infections
(STIs). There is silence on sex both at home and school. This cross
sectional descriptive analytical study interviews a random sample of
827 students and 13 teachers on knowledge, perception and
acceptability to a comprehensive adolescent sexual and reproductive
health education in “O” and “A” level secondary schools in Gulu
District. Quantitative data was analyzed using SPSS 16.0. Directed
content analysis of themes of transcribed qualitative data was
conducted manually for common codes, sub-categories and
categories. Of the 827 students; 54.3% (449) reported being in a
sexual relationship especially those aged 15-17 years. Majority
96.1% (807) supported the teaching of a comprehensive ASRHE,
citing no negative impact 71.5% (601). Majority 81.6% (686) agreed
that such education could help prevention of STIs, abortions and
teenage pregnancies, and that it should be taught by health workers
69.0% (580). Majority 76.6% (203) reported that ASRHE was not
currently being taught in their schools. Students had low knowledge
levels and misconceptions about ASRHE. ASRHE was highly
acceptable though not being emphasized; its success in school
settings requires multidisciplinary culturally sensitive approaches
amongst which health workers should be frontiers.
Abstract: Despite of the preponderant role played by cement among the construction materials, it is today considered as a material destructing the environment due to the large quantities of carbon dioxide exhausted during its manufacture. Besides, global warming is now recognized worldwide as the new threat to the humankind against which advanced countries are investigating measures to reduce the current amount of exhausted gases to the half by 2050. Accordingly, efforts to reduce green gases are exerted in all industrial fields. Especially, the cement industry strives to reduce the consumption of cement through the development of alkali-activated geopolymer mortars using industrial byproducts like bottom ash. This study intends to gather basic data on the flowability and strength development characteristics of alkali-activated geopolymer mortar by examining its FT-IT features with respect to the effects and strength of the alkali-activator in order to develop bottom ash-based alkali-activated geopolymer mortar. The results show that the 35:65 mass ratio of sodium hydroxide to sodium silicate is appropriate and that a molarity of 9M for sodium hydroxide is advantageous. The ratio of the alkali-activators to bottom ash is seen to have poor effect on the strength. Moreover, the FT-IR analysis reveals that larger improvement of the strength shifts the peak from 1060 cm–1 (T-O, T=Si or Al) toward shorter wavenumber.
Abstract: Greenhouse gases (GHG) emissions impose major
threat to global warming potential (GWP). Unfortunately
manufacturing sector is one of the major sources that contribute
towards the rapid increase in greenhouse gases (GHG) emissions. In
manufacturing sector electric power consumption is the major driver
that influences CO2 emission. Titanium alloys are widely utilized in
aerospace, automotive and petrochemical sectors because of their
high strength to weight ratio and corrosion resistance. Titanium
alloys are termed as difficult to cut materials because of their poor
machinability rating. The present study analyzes energy consumption
during cutting with reference to material removal rate (MRR).
Surface roughness was also measured in order to optimize energy
consumption.
Abstract: This study discusses the stumbling blocks stifling the
adoption of GPS technology in the public sector of Pakistan. This
study has been carried out in order to describe the value of GPS
technology and its adoption at various public sector organisations in
Pakistan. Sample size for the research conducted was 200; personnel
working in public sector having age above 29 years were surveyed.
Data collected for this research has been quantitatively analysed with
the help of SPSS. Regression analysis, correlation and cross
tabulation were the techniques used to determine the strength of
relationship between key variables. Findings of this research indicate
that main hurdles in GPS adoption in the public sector of Pakistan are
lack of awareness about GPS among masses in general and the
stakeholders in particular, lack of initiative on part of government in
promoting new technologies, unavailability of GPS infrastructure in
Pakistan and prohibitions on map availability because of security
reasons.
Abstract: Increased physical fitness participation has been
paralleled by increasedoveruse injuries such as insertional Achilles
tendinosis (AT). Treatment has provided inconsistentresults. The use
of extracorporeal shockwave therapy (ECSWT) offers a new
treatment consideration.The purpose of this study was to assess the
effects of ECSWTon pain, function, range of motion (ROM), joint
mobility and strength in patients with AT. Thirty subjects were
treated with ECSWT and measures were takenbefore and three
months after treatment. There was significant differences in visual
analog scale (VAS) scores for pain at rest (p=0.002); after activity
(p= 0.0001); overall improvement(p=0.0001); Lower Extremity
Functional Scale (LEFS) scores (p=0.002); dorsiflexion range of
motion (ROM) (p=0.0001); plantarflexion strength (p=0.025);
talocrural joint anterior glide (p=0.046); and subtalar joint medial and
lateral glide (p=0.025).ECSWT offers a new intervention that may
limit the progression of the disorder and the long term healthcare
costs associated with AT.
Abstract: The composite materials were prepared by sawdust, cassava starch and natural rubber latex (NR). The mixtures of 15%w/v gelatinized cassava starch and 15%w/v PVOH were used as the binder of these composite materials. The concentrated rubber latex was added to the mixtures. They were mixed rigorously to the treated sawdust in the ratio of 70:30 until achive uniform dispersion. The batters were subjected to the hot compression moulding at the temperature of 160°C and 3,000 psi pressure for 5 min. The experimental results showed that the mechanical properties of composite materials, which contained the gelatinized cassava starch and PVOH in the ratio of 2:1, 20% NR latex by weight of the dry starch and treated sawdust with 5%NaOH or 1% BPO, were the best. It contributed the maximal compression strength (341.10 + 26.11 N), puncture resistance (8.79 + 0.98 N/mm2) and flexural strength (3.99 + 0.72N/mm2). It is also found that the physicochemical and mechanical properties of composites strongly depends on the interface quality of sawdust, cassava starch and NR latex.
Abstract: Soft clays are defined as cohesive soil whose water
content is higher than its liquid limits. Thus, soil-cement mixing is
adopted to improve the ground conditions by enhancing the strength
and deformation characteristics of the soft clays. For the above
mentioned reasons, a series of laboratory tests were carried out to
study some fundamental mechanical properties of cement stabilized
soft clay. The test specimens were prepared by varying the portion of
ordinary Portland cement to the soft clay sample retrieved from the
test site of RECESS (Research Centre for Soft Soil). Comparisons
were made for both homogeneous and columnar system specimens
by relating the effects of cement stabilized clay of for 0, 5 and 10 %
cement and curing for 3, 28 and 56 days. The mechanical properties
examined included one-dimensional compressibility and undrained
shear strength. For the mechanical properties, both homogeneous and
columnar system specimens were prepared to examine the effect of
different cement contents and curing periods on the stabilized soil.
The one-dimensional compressibility test was conducted using an
oedometer, while a direct shear box was used for measuring the
undrained shear strength. The higher the value of cement content, the
greater is the enhancement of the yield stress and the decrease of
compression index. The value of cement content in a specimen is a
more active parameter than the curing period.
Abstract: In this paper the Analytic Network Process (ANP) is
applied to the selection of photovoltaic (PV) solar power projects.
These projects follow a long management and execution process
from plant site selection to plant start-up. As a consequence, there are
many risks of time delays and even of project stoppage.
In the case study presented in this paper a top manager of an
important Spanish company that operates in the power market has to
decide on the best PV project (from four alternative projects) to
invest based on risk minimization. The manager identified 50 project
execution delay and/or stoppage risks.
The influences among elements of the network (groups of risks
and alternatives) were identified and analyzed using the ANP
multicriteria decision analysis method. After analyzing the results the
main conclusion is that the network model can manage all the
information of the real-world problem and thus it is a decision
analysis model recommended by the authors. The strengths and
weaknesses ANP as a multicriteria decision analysis tool are also
described in the paper.
Abstract: The first and basic cause of the failure of concrete is repeated freezing (thawing) of moisture contained in the pores, microcracks, and cavities of the concrete. On transition to ice, water existing in the free state in cracks increases in volume, expanding the recess in which freezing occurs. A reduction in strength below the initial value is to be expected and further cycle of freezing and thawing have a further marked effect. By using some experimental parameters like nuclear magnetic resonance variation (NMR), enthalpy-temperature (or heat capacity) variation, we can resolve between the various water states and their effect on concrete properties during cooling through the freezing transition temperature range. The main objective of this paper is to describe the principal type of water responsible for the reduction in strength and structural damage (frost damage) of concrete following repeated freeze –thaw cycles. Some experimental work was carried out at the institute of cryogenics to determine what happens to water in concrete during the freezing transition.
Abstract: In this work, the primary compressive strength
components of human femur trabecular bone are qualitatively
assessed using image processing and wavelet analysis. The Primary
Compressive (PC) component in planar radiographic femur trabecular
images (N=50) is delineated by semi-automatic image processing
procedure. Auto threshold binarization algorithm is employed to
recognize the presence of mineralization in the digitized images. The
qualitative parameters such as apparent mineralization and total area
associated with the PC region are derived for normal and abnormal
images.The two-dimensional discrete wavelet transforms are utilized
to obtain appropriate features that quantify texture changes in medical
images .The normal and abnormal samples of the human femur are
comprehensively analyzed using Harr wavelet.The six statistical
parameters such as mean, median, mode, standard deviation, mean
absolute deviation and median absolute deviation are derived at level
4 decomposition for both approximation and horizontal wavelet
coefficients. The correlation coefficient of various wavelet derived
parameters with normal and abnormal for both approximated and
horizontal coefficients are estimated. It is seen that in almost all cases
the abnormal show higher degree of correlation than normals. Further
the parameters derived from approximation coefficient show more
correlation than those derived from the horizontal coefficients. The
parameters mean and median computed at the output of level 4 Harr
wavelet channel was found to be a useful predictor to delineate the
normal and the abnormal groups.
Abstract: Cement, the most widely used construction material
is very brittle and characterized by low tensile strength and strain
capacity. Macro to nano fibers are added to cement to provide
tensile strength and ductility to it. Carbon Nanotube (CNT), one of
the nanofibers, has proven to be a promising reinforcing material in
the cement composites because of its outstanding mechanical
properties and its ability to close cracks at the nano level. The
experimental investigations for CNT reinforced cement is costly,
time consuming and involves huge number of trials. Mathematical
modeling of CNT reinforced cement can be done effectively and
efficiently to arrive at the mechanical properties and to reduce the
number of trials in the experiments. Hence, an attempt is made to
numerically study the effective mechanical properties of CNT
reinforced cement numerically using Representative Volume
Element (RVE) method. The enhancement in its mechanical
properties for different percentage of CNTs is studied in detail.
Abstract: Biometric measures of one kind or another have been
used to identify people since ancient times, with handwritten
signatures, facial features, and fingerprints being the traditional
methods. Of late, Systems have been built that automate the task of
recognition, using these methods and newer ones, such as hand
geometry, voiceprints and iris patterns. These systems have different
strengths and weaknesses. This work is a two-section composition. In
the starting section, we present an analytical and comparative study
of common biometric techniques. The performance of each of them
has been viewed and then tabularized as a result. The latter section
involves the actual implementation of the techniques under
consideration that has been done using a state of the art tool called,
MATLAB. This tool aids to effectively portray the corresponding
results and effects.
Abstract: In this paper the strength of adhesive joint under
tension and bending is discussed on the basis of intensity of
singular stress by the application of FEM. A useful method is
presented with focusing on the stress at the edge of interface
between the adhesive and adherent obtained by FEM. After
analyzing the adhesive joint strength with all material
combinations, it is found that to improve the interface strength,
thin adhesive layers are desirable because the intensity of
singular stress decreases with decreasing the thickness.
Abstract: A well balanced numerical scheme based on
stationary waves for shallow water flows with arbitrary topography
has been introduced by Thanh et al. [18]. The scheme was
constructed so that it maintains equilibrium states and tests indicate
that it is stable and fast. Applying the well-balanced scheme for the
one-dimensional shallow water equations, we study the early shock
waves propagation towards the Phuket coast in Southern Thailand
during a hypothetical tsunami. The initial tsunami wave is generated
in the deep ocean with the strength that of Indonesian tsunami of
2004.
Abstract: Reinforced Concrete (RC) structures strengthened
with fiber reinforced polymer (FRP) lack in thermal resistance under
elevated temperatures in the event of fire. This phenomenon led to
the lining of strengthened concrete with thin high performance
cementitious composites (THPCC) to protect the substrate against
elevated temperature. Elevated temperature effects on THPCC, based
on different cementitious materials have been studied in the past but
high-alumina cement (HAC)-based THPCC have not been well
characterized. This research study will focus on the THPCC based on
HAC replaced by 60%, 70%, 80% and 85% of ground granulated
blast furnace slag (GGBS). Samples were evaluated by the
measurement of their mechanical strength (28 & 56 days of curing)
after exposed to 400°C, 600°C and 28°C of room temperature for
comparison and corroborated by their microstructure study. Results
showed that among all mixtures, the mix containing only HAC
showed the highest compressive strength after exposed to 600°C as
compared to other mixtures. However, the tensile strength of THPCC
made of HAC and 60% GGBS content was comparable to the
THPCC with HAC only after exposed to 600°C. Field emission
scanning electron microscopy (FESEM) images of THPCC
accompanying Energy Dispersive X-ray (EDX) microanalysis
revealed that the microstructure deteriorated considerably after
exposure to elevated temperatures which led to the decrease in
mechanical strength.
Abstract: This research was to evaluate a technical feasibility of
making single-layer experimental particleboard panels from bamboo
waste (Dendrocalamus asper Backer) by converting bamboo into
strips, which are used to make laminated bamboo furniture. Variable
factors were density (600, 700 and 800 kg/m3) and temperature of
condition (25, 40 and 55 °C). The experimental panels were tested for
their physical and mechanical properties including modulus of
elasticity (MOE), modulus of rupture (MOR), internal bonding
strength (IB), screw holding strength (SH) and thickness swelling
values according to the procedures defined by Japanese Industrial
Standard (JIS). The test result of mechanical properties showed that
the MOR, MOE and IB values were not in the set criteria, except the
MOR values at the density of 700 kg/m3 at 25 °C and at the density
of 800 kg/m3 at 25 and 40 °C, the IB values at the density of 600
kg/m3, at 40 °C, and at the density of 800 kg/m3 at 55 °C. The SH
values had the test result according to the set standard, except with
the density of 600 kg/m3, at 40 and 55 °C. Conclusively, a valuable
renewable biomass, bamboo waste could be used to manufacture
boards.