Abstract: The objective of this study was to improve our
understanding of vulnerability and environmental change; it's causes
basically show the intensity, its distribution and human-environment
effect on the ecosystem in the Apodi Valley Region, This paper is
identify, assess and classify vulnerability and environmental change
in the Apodi valley region using a combined approach of landscape
pattern and ecosystem sensitivity. Models were developed using the
following five thematic layers: Geology, geomorphology, soil,
vegetation and land use/cover, by means of a Geographical
Information Systems (GIS)-based on hydro-geophysical parameters.
In spite of the data problems and shortcomings, using ESRI-s ArcGIS
9.3 program, the vulnerability score, to classify, weight and combine
a number of 15 separate land cover classes to create a single indicator
provides a reliable measure of differences (6 classes) among regions
and communities that are exposed to similar ranges of hazards.
Indeed, the ongoing and active development of vulnerability
concepts and methods have already produced some tools to help
overcome common issues, such as acting in a context of high
uncertainties, taking into account the dynamics and spatial scale of
asocial-ecological system, or gathering viewpoints from different
sciences to combine human and impact-based approaches. Based on
this assessment, this paper proposes concrete perspectives and
possibilities to benefit from existing commonalities in the
construction and application of assessment tools.
Abstract: The current paper conceptualizes the technique of
release consistency indispensable with the concept of
synchronization that is user-defined. Programming model concreted
with object and class is illustrated and demonstrated. The essence of
the paper is phases, events and parallel computing execution .The
technique by which the values are visible on shared variables is
implemented. The second part of the paper consist of user defined
high level synchronization primitives implementation and system
architecture with memory protocols. There is a proposition of
techniques which are core in deciding the validating and invalidating
a stall page .
Abstract: The paper deals with quality labels used in the food products market, especially with labels of quality, labels of origin, and labels of organic farming. The aim of the paper is to identify perception of these labels by consumers in the Czech Republic. The first part refers to the definition and specification of food quality labels that are relevant in the Czech Republic. The second part includes the discussion of marketing research results. Data were collected with personal questioning method. Empirical findings on 150 respondents are related to consumer awareness and perception of national and European food quality labels used in the Czech Republic, attitudes to purchases of labelled products, and interest in information regarding the labels. Statistical methods, in the concrete Pearson´s chi-square test of independence, coefficient of contingency, and coefficient of association are used to determinate if significant differences do exist among selected demographic categories of Czech consumers.
Abstract: Urban disaster risks and vulnerabilities are great problems for Turkey. The annual loss of life and property through disaster in the world-s major metropolitan areas is increasing. Urban concentrations of the poor and less-informed in environmentally fragile locations suffer the impact of disaster disproportionately. Gecekondu (squatter) developments will compound the inherent risks associated with high-density environments, in appropriate technologies, and inadequate infrastructure. On the other hand, there are many geological disadvantages such as sitting on top of active tectonic plate boundaries, and why having avalanche, flood, and landslide and drought prone areas in Turkey. However, this natural formation is inevitable; the only way to survive in such a harsh geography is to be aware of importance of these natural events and to take political and physical measures. The main aim of this research is to bring up the magnitude of natural hazard risks in Izmir built-up zone, not being taken into consideration adequately. Because the dimensions of the peril are not taken seriously enough, the natural hazard risks, which are commonly well known, are not considered important or they are being forgotten after some time passes. Within this research, the magnitude of natural hazard risks for Izmir is being presented in the scope of concrete and local researches over Izmir risky areas.
Abstract: Concrete strength evaluated from compression tests
on cores is affected by several factors causing differences from the
in-situ strength at the location from which the core specimen was
extracted. Among the factors, there is the damage possibly occurring
during the drilling phase that generally leads to underestimate the
actual in-situ strength. In order to quantify this effect, in this study
two wide datasets have been examined, including: (i) about 500 core
specimens extracted from Reinforced Concrete existing structures,
and (ii) about 600 cube specimens taken during the construction of
new structures in the framework of routine acceptance control. The
two experimental datasets have been compared in terms of
compression strength and specific weight values, accounting for the
main factors affecting a concrete property, that is type and amount of
cement, aggregates' grading, type and maximum size of aggregates,
water/cement ratio, placing and curing modality, concrete age. The
results show that the magnitude of the strength reduction due to
drilling damage is strongly affected by the actual properties of
concrete, being inversely proportional to its strength. Therefore, the
application of a single value of the correction coefficient, as generally
suggested in the technical literature and in structural codes, appears
inappropriate. A set of values of the drilling damage coefficient is
suggested as a function of the strength obtained from compressive
tests on cores.
Abstract: The recycling of concrete, bricks and masonry rubble
as concrete aggregates is an important way to contribute to a
sustainable material flow. However, there are still various
uncertainties limiting the widespread use of Recycled Concrete
Aggregates (RCA). The fluctuations in the composition of grade
recycled aggregates and their influence on the properties of fresh and
hardened concrete are of particular concern regarding the use of
RCA. Most of problems occurring while using recycled concrete
aggregates as aggregates are due to higher porosity and hence higher
water absorption, lower mechanical strengths, residual impurities on
the surface of the RCA forming weaker bond between cement paste
and aggregate. So, the reuse of RCA is still limited. Efficient
polymer based treatment is proposed in order to reuse RCA easier.
The silicon-based polymer treatments of RCA were carried out and
were compared. This kind of treatment can improve the properties of
RCA such as the rate of water absorption on treated RCA is
significantly reduced.
Abstract: Nowadays, the performance required for concrete
structures is more complicated and diversified. Self-compacting
concrete is a fluid mixture suitable for placing in structures with
congested reinforcement without vibration. Self-compacting concrete
development must ensure a good balance between deformability and
stability. Also, compatibility is affected by the characteristics of
materials and the mix proportions; it becomes necessary to evolve a
procedure for mix design of SCC.
This paper presents an experimental procedure for the design of
self-compacting concrete mixes with different water-cement ratios
(w/c) and other constant ratios by local materials. The test results for
acceptance characteristics of self-compacting concrete such as slump
flow, V-funnel and L-Box are presented. Further, compressive
strength, tensile strength and modulus of elasticity of specimens were
also determined and results are included here
Abstract: In this survey the process of crack propagation at the
toe of concrete gravity dam is investigated by applying principals
and criteria of linear elastic fracture mechanic. Simulating process of
earthquake conditions for three models of dam with different
geometrical condition, in empty reservoir under plain stress is
calculated through special fracture mechanic software FRANNC2D
[1] for determining fracture mechanic criteria. The outcomes showed
that in spite of the primary expectations, the simultaneous existence
of fillet in both toe and heel area (model 3), the rate of maximum
principal stress has not been decreased; however, even the maximum
principal stress has increased, so it caused stress intensity factors
increase which is undesirable. On the other hand, the dam with heel
fillet has shown the best attitude and it is because of items like
decreasing the rates of maximum and minimum principal stresses and
also is related to decreasing the rates of stress intensity factors for 1st
& 2nd modes of the model.
Abstract: With respect to the dissipation of energy through
plastic deformation of joints of prefabricated wall units, the paper
points out the principal importance of efficient reinforcement of the
prefabricated system at its joints. The method, quality and amount of
reinforcement are essential for reaching the necessary degree of joint
ductility. The paper presents partial results of experimental research
of vertical joints of prefabricated units exposed to monotonously
rising loading and repetitive shear force and formulates a conclusion
that the limit state of the structure as a whole is preceded by the
disintegration of joints, or that the structure tends to pass from
linearly elastic behaviour to non-linearly elastic to plastic behaviour
by exceeding the proportional elastic limit in joints.Experimental
verification on a model of a 7-storey prefabricated structure revealed
weak points in its load-bearing systems, mainly at places of critical
points around openings situated in close proximity to vertical joints
of mutually perpendicularly oriented walls.
Abstract: High Voltage (HV) transmission lines are widely
spread around residential places. They take all forms of shapes:
concrete, steel, and timber poles. Earth grid always form part of the
HV transmission structure, whereat soil resistivity value is one of the
main inputs when it comes to determining the earth grid
requirements. In this paper, the soil structure and its implication on
the electrode resistance of HV transmission poles will be explored. In
Addition, this paper will present simulation for various soil structures
using IEEE and Australian standards to verify the computation with
CDEGS software. Furthermore, the split factor behavior under
different soil resistivity structure will be presented using CDEGS
simulations.
Abstract: Analytical procedure was carried out in this paper to
calculate the ultimate load capacity of reinforced concrete corbels
strengthened or repaired externally with CFRP sheets. Strut and tie
method and shear friction method proposed earlier for analyzing
reinforced concrete corbels were modified to incorporate the effect of
external CFRP sheets bonded to the corbel. The points of weakness
of any method that lead to an inaccuracy, especially when
overestimating test results were checked and discussed. Comparison
of prediction with the test data indicates that the ratio of test /
calculated ultimate load is 0.82 and 1.17 using strut and tie method
and shear friction method, respectively. If the limits of maximum
shear stress is followed, the calculated ultimate load capacity using
shear friction method was found to underestimates test data
considerably.
Abstract: The storage of chemical fertilizers in concrete building often leads to durability problems due to chemical attack. The damage of concrete is mostly caused by certain ammonium salts. The main purpose of the research is to investigate the durability properties of concrete being exposed to ammonium nitrate solution. In this investigation, experiments are conducted on concrete type G50 and G60. The leaching process is achieved by the use of 20% concentration solution of ammonium nitrate. The durability properties investigated are water absorption, volume of permeable voids, and sorptivity. Compressive strength, pH value, and degradation depth are measured after a certain period of leaching. A decrease in compressive strength and an increase in porosity are found through the conducted experiments. Apart from that, the experimental data shows that pH value decreases with increased leaching time while the degradation depth of concrete increases with leaching time. By comparing concrete type G50 and G60, concrete type G60 is more resistant to ammonium nitrate attack.
Abstract: Many single or multispan arch bridges are
strengthened with the addition of some kind of structural support
between adjacent arches of multispan or beside the arch barrel of a
single span to increase the strength of the overall structure. It was
traditionally formed by either placing loose rubble masonry blocks
between the arches and beside the arches or using mortar or concrete
to construct a more substantial structural bond between the spans. On
the other hand backing materials are present in some existing bridges.
Existing arch assessment procedures generally ignore the effects of
backing materials. In this paper an investigation of the effects of
backing on ratings for masonry arch bridges is carried out. It is
observed that increasing the overall lateral stability of the arch
system through the inclusion of structural backing results in an
enhanced failure load by reducing the likelihood of any tension
occurring at the top of the arch.
Abstract: This paper seeks to explore the actual classroom
setting, to examine its role for students- learning, and attitude in the
class. It presents a theoretical approach of the classroom as system to
be explored and examines the concrete reality of Greek secondary
education students, under the light of the above approach. Based on
the findings of a quantitative and qualitative research, authors
propose a rather ontological approach of the classroom and underline
what the key-elements for such approach should be. The paper
explores extensively the theoretical dimensions for the change of
paradigm required and addresses the new issues to be considered.
Abstract: This paper reports on the influence of surface-treated coarse recycled concrete aggregate (RCA) on developing the compressive strength of concrete. The coarse RCA was initially treated by separately impregnating it in calcium metasilicate (CM) or wollastonite and nanosilica (NS) prepared at various concentrations. The effects of both treatment materials on concrete properties (e.g., slump, density and compressive strength) were evaluated. Scanning electron microscopy (SEM) analysis was performed to examine the microstructure of the resulting concrete. Results show that the effective use of treated coarse RCA significantly enhances the compressive strength of concrete. This result is supported by the SEM analysis, which indicates the formation of a dense interface between the treated coarse RCA and the cement matrix. Coarse RCA impregnated in CM solution results in better concrete strength than NS, and the optimum concentration of CM solution recommended for treated coarse RCA is 10%.
Abstract: The research investigates the effects of super plasticizer and molarity of sodium hydroxide alkaline solution on the workability, microstructure and compressive strength of self compacting geopolymer concrete (SCGC). SCGC is an improved way of concreting execution that does not require compaction and is made by complete elimination of ordinary Portland cement content. The parameters studied were superplasticizer (SP) dosage and molarity of NaOH solution. SCGC were synthesized from low calcium fly ash, activated by combinations of sodium hydroxide and sodium silicate solutions, and by incorporation of superplasticizer for self compactability. The workability properties such as filling ability, passing ability and resistance to segregation were assessed using slump flow, T-50, V-funnel, L-Box and J-ring test methods. It was found that the essential workability requirements for self compactability according to EFNARC were satisfied. Results showed that the workability and compressive strength improved with the increase in superplasticizer dosage. An increase in strength and a decrease in workability of these concrete samples were observed with the increase in molarity of NaOH solution from 8M to 14M. Improvement of interfacial transition zone (ITZ) and micro structure with the increase of SP and increase of concentration from 8M to 12M were also identified.
Abstract: The growing importance of sustainability in corporate
policies represents a great opportunity for workers to gain more
consideration, with great benefits to their well being. Sustainable
work is believed to be one which improves the organization-s
performance and fosters professional development as well as
workers- health. In a multiple case study based on document
research, information was sought about work activities and their
sustainability or corporate social responsibility (CSR) policies, as
disseminated by corporations. All the companies devoted attention to
work activities and delivered a good amount of information about
them. Nevertheless, the information presented was generic; all the
actions developed were top-down and there was no information about
the impact of changes aimed at sustainability on the workers-
activities. It was found that the companies seemed to be at an early
stage. In the future, they need to show more commitment through
concrete goals: they must be aware that workers contribute directly to
the corporations- sustainability. This would allow room for
Ergonomics and Work Psychodynamics to be incorporated and to be
useful for both companies and society, so as to promote and ensure
work sustainability.
Abstract: In this paper, a parametric experimental study for producing paving blocks using fine and coarse waste glass is presented. Some of the physical and mechanical properties of paving blocks having various levels of fine glass (FG) and coarse glass (CG) replacements with fine aggregate (FA) are investigated. The test results show that the replacement of FG by FA at level of 20% by weight has a significant effect on the compressive strength, flexural strength, splitting tensile strength and abrasion resistance of the paving blocks as compared with the control sample because of puzzolanic nature of FG. The compressive strength, flexural strength, splitting tensile strength and abrasion resistance of the paving block samples in the FG replacement level of 20% are 69%, 90%, 47% and 15 % higher as compared with the control sample respectively. It is reported in the earlier works the replacement of FG by FA at level of 20% by weight suppress the alkali-silica reaction (ASR) in the concrete. The test results show that the FG at level of 20% has a potential to be used in the production of paving blocks. The beneficial effect on these properties of CG replacement with FA is little as compared with FG.
Abstract: This study is to evaluate the behavior of integral and
segmental specimens through static and cyclic tests. Integral
specimens were made with the same size to be compared with
segmental specimens that were made by connected precast members.
To evaluate its bending performance and serviceability, 1 integral and
3 segmental specimens were tested under static load. And 1 integral
and 2 segmental specimens were tested under cyclic load, respectively.
Different load ranges were considered in the cyclic tests to evaluate the
safety and serviceability. The test results showed that under static
loading, segmental specimens had about 94% of the integral
specimen's maximum moment, averagely. Under cyclic loading, the
segmental specimens showed that had enough safety in the range of
higher than service load and enough serviceability. In conclusion, the
maximum crack width (0.16mm) satisfied the allowable crack width
(0.30mm) in the range of service load.