Vol. 6(12) December 2013
Future-oriented activities as a concept for improved
disaster risk management
Aubrecht Christoph*, Özceylan Aubrecht Dilek, Klerx Joachim and Freire Sérgio
This study promotes the idea of future-oriented thinking
in disaster risk management and describes how forward-looking activities can play
a role in reduction of future risks and impacts. It explicitly highlights how a
common future-oriented proactive attitude built-up in participative stakeholder
communication networks can assist in shaping and creating a vision of a less uncertain
and ambiguous future. First, the advancement of the disaster management concept
and its various stages, including risk analysis, mitigation and response are explained.
Forward-looking activities on short- and long-term temporal scales are introduced
and put into a disaster risk management context. Recent developments in risk and
crisis communication are discussed as evolving in a new environment that emphasizes
network-centric communication shaped by the increasing influence of web 2.0 social
media platforms. It is further described how future-oriented processes and inherent
communication approaches can improve disaster risk management. Finally, the various
time-scale-dependent future-oriented activities are conceptually integrated into
a framework of risk governance. Active and participative communication is thereby
seen as the key for successfully implementing risk governance and favor disaster
mitigation and future risk reduction.
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An experimental study on carbon dioxide displacing
coal bed methane under supercritical conditions
Ni Xiaoming, Chen Wenxue* Liu Quanzhong and Wang Yanbin
Identifying the effects of carbon dioxide displacing
coal bed methane under supercritical condition can provide a theoretical basis for
the carbon dioxide injection parameters of deep coal seam. Regarding Sihe mine anthracite
and Yuwu mine lean coal as the research objects, the adsorption experiments and
displacement experiments of carbon dioxide and coal bed methane under supercritical
conditions were carried out. According to the nature of the volumetric method for
testing adsorption, the absolute adsorption of carbon dioxide and coal bed methane
under different pressures was calculated and the Langmuir pressure and Langmuir
volume of carbon dioxide and coal bed methane were obtained. With Langmuir isothermal
adsorption model and its extensions, the desorption rate of carbon dioxide displacing
coal bed methane at unit pressure drop under supercritical pressure range and low
pressure range were calculated. The results showed that the desorption rate of the
carbon dioxide displacing coal bed methane at unit pressure drop under supercritical
pressure range or low pressure range both are higher than the desorption rate of
coal bed methane in the natural desorption states at unit pressure drop. Desorption
rate of coal bed methane at unit pressure drop under the supercritical pressure
range or low pressure range for Anthracite increased by 268.13% and 8.71%, and lean
coal increased by 73.71% and 3.75%; The effect of carbon dioxide displacing coal
bed methane under supercritical pressure range was more obvious.
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Mechanism and Experiment of Acoustic Wave influencing
Gas Adsorption in Coal
Xiangchun Li*, Baisheng Nie, Fangbin Liu, Chunli Yang and Shoutao Hu
The experiment system of acoustic wave influencing gas
adsorption in coal was designed. By the use of the experiment equipment, characteristics
of acoustic wave influencing gas adsorption in coal and mechanism of acoustic wave
influencing gas adsorption in coal were studied. The research results showed that
under the action of acoustic wave gas content of coal sample and adsorption ability
reduces. The mechanism of acoustic wave influencing gas adsorption in coal was mechanical
effect, heat effect, directing function effect and cavitation effect. The research
provides a new idea to the study of enhancing coal-bed permeability and gas development.
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Detection of Lack of Penetration Weld defect from
Radiographic Weld Images for Avoiding Disaster using Advanced Median Filter and
Modified Hough Transform
Vaithiyanathan V.* Anishin Raj M.M., Venkatraman B., Radha Krishnan V., Priyadharsini
C. and Bhuvaneshwari K.
The weld defects in nuclear power plants and petrochemical
industries may cause disaster if undetected at the initial stage of installation.
Identifying the defects in radiographic images by human interpreter or automated
programs is a challenging task due to the presence of various noises and the highly
dark nature of the industrial radiography. This paper proposes a new advanced fast
processing Median filter for noise removal and also proposes an enhanced method
of segmentation using Hough Transform for a restricted triangular region. A novel
improvement for the Dijkstra’s three way partitioning technique for sorting pixels
of an image faster in less number of swaps when compared to the Bentley McIlory
algorithm and the Dijkstra’s algorithm, is used for designing a fast processing
median filter for noise removal. The Hough transform is a reliable technique that
can be used for segmenting lack of Penetration weld defect which is basically straight
line in nature. In Hough Transform based segmentation the entire image is processed
for accumulating votes in an array of accumulator. But the main limitation is its
high computational complexity and the large amount of memory that needed to be allocated
while processing. Experimental results show that the Hough Transform applied on
the restricted triangular region provides an accurate segmentation of lack of penetration
weld defect with reduced search space.
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Avoiding occupational accidents and man-made disasters:
A semi-qualitative study in 27 companies investigating factors influencing safety
stall points
Reniers Genserik L.L.
The effectiveness of occupational safety is measured
by the number of occupational accidents happening within a company in a year and
by then calculating the Loss Time Injury Frequency Rate (LTIFR). After a prolonged
period of LTIFR-decline or stagnation, the LTIFR may increase again at a certain
point in time. We call this point in time a “safety stall point”. This study was
carried out in 27 companies to identify the different factors which lead to postponing
or avoiding safety stall points. Results indicate that safety stall points may indeed
be influenced and what the various parameters are that may do so. Recommendations
are formulated regards how to avoid or postpone safety stall points. If safety stall
points can be avoided, obviously this has an important effect on the avoidance of
disasters as well. Man-made disasters’ likelihood is decreased, as many disasters
(not all of them!) are avoided by focusing on avoiding occupational accidents.
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Numerical computing of heat safety of TNT in cook-off
test
Wang Cheng*, Cao Xiangfei, Ning Jianguo and Zhao Haitao
In order to study the thermal reaction principles of
explosives with different sizes and at different heating rates, this paper builds
a cook-off test model of explosives. In this model, we use the Arrhenius equation
to describe autothermal reaction of explosives, consider the endothermic phase transition
and the change of heat conductivity at different kinds of state of TNT, use the
finite difference method to discretize the model and make program to solve it. We
calculate the process of the cook-off test at the same heating rate but with different
sizes and with the same size but at different heating rates. The results show that
the ignition temperature almost keeps unchanged with different sizes of TNT. As
the size of TNT increases, the ignition position moves outward from the shaft of
cylindrical model. However, the heating rate has a great influence on the ignition
time and position. When heating rate rises, the ignition time shortens, the ignition
position moves forward to the edge, the temperature distribution becomes more uneven
and the time for phase transition with the different distance to the shaft is greatly
affected. When the heating rate is 1K/s, the TNT in the center of the model has
not had phase transition when whole explosive explodes. Heating rate has little
effect on the ignition temperature while the ambient temperature has positive relation
with heating rate when explosive ignites.
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Gas Diffusion Model through Coal Particles and Parameters
Calculation
Baisheng Nie*, Tao Yang, Hongqi Lu, Xiangchun Li and Longlong Yang
The micro-mechanism of gas diffusion in coal was analyzed.
The process of gas diffusion through coal particles and the mathematical physical
model under the third kind boundary condition was determined to obtain the rules
of gas diffusion through coal particles of different sizes. The analytical solution
of the equation was obtained by the method of mathematical physics. The parameters
of analytical solutions and the implications of parameters were analyzed. The results
show that in coal body there are three kinds of diffusion modes: Fick diffusion,
Knudsen diffusion, transitional diffusion, surface diffusion and crystal diffusion.
The mathematical and physical model of methane diffusion under the third boundary
condition was built. According to the analytical results, Biot criterion (Bi) and
Fourier criterion (F0) of mass transfer can represent and reflect the features of
gas diffusion field of coal particles. Moreover, the measurement method of gas diffusion
coefficient and surface mass transfer coefficient are introduced and an example
of measurement is given. Also, the ultimate diffusion volume was gotten by applying
the theory and model. The achievement can provide the support to prevent disasters
related to methane in coal mines.
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Effects of coal-rock strength on mechanical behavior
and failure mechanism of samples composed of coal and rock
Liu Jie and Wang En-yuan*
In order to study the effects of roof-floor rock and
coal strength on the deformation and failure of coal-rock masses system, the deformation
and failure processes of various coal-rock composite samples with different strength
are simulated by the RFPA-2D software, based on which the effects of the rock and
coal strength on the failure mode, mechanical behavior and deformation rule of the
samples are analyzed respectively. The results show that the failure mode of the
composite sample depends mainly on the strength of its coal part, stress-strain
curve characteristics and uniaxial compression strength depend on the coal part
inside it, pre-peak secant modulus and the peak strain are determined by rock and
coal; the difference in deformation between rock and coal increases with the difference
in strength between them. The theoretical model for deformation and failure of loaded
composite sample is established and the interaction mechanism between rock and coal
and the effect on instability and failure of composite sample are studied. For the
mechanical behavior of composite sample, the calculation results from the theoretical
model are in good agreement with the simulation results of RFPA-2D software.
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Shaking Table Modeling of Embankment Slope Response
to Earthquake Loading
Lin Yu-liang
Based on the prototype of single-line unballasted track
railway embankment, embankment slope model with the scale of 1:8 was designed. The
recorded Wenchuan excitations with different peak accelerations were performed in
XZ-bi direction. Acceleration responses of embankment slope were analyzed both in
time domain and frequency domain. The acceleration response spectrum of a single-degree-of-freedom
(SDOF) system was also calculated. Results show that the intensity of acceleration
response in slope surface is greater than that in mid-section. Acceleration magnification
increases nonlinearly along the height of embankment slope and presents a decreasing
trend with the increase of input peak acceleration. Exponential function and logarithmic
function are recommended to describe such decreasing trend. Seismic energy with
high-frequency is absorbed by embankment slope and seismic energy with frequency
close to the natural frequency of embankment slope is enhanced when the seismic
wave transmits upwards. The natural frequency of embankment slope is determined
as 4.5 Hz with a suggestion that the construction of structure with the natural
period close to 0.22 s on embankment slope should be avoided.
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A Coupled Model for predicting the Effect of the Three
Gorges Reservoir on Downstream River-Connected Lakes
Dai L. Q., Dai H. C.*, Mao J. Q. and Zhang P. P.
Reservoirs construction along with associated regulation
of the downstream water course is a major way by which human activity can modify
the hydrologic regime of rivers and then has a potential effect on downstream river-connected
lakes which are sensitive to water level variation. In order to quantitatively predict
and assess the operation of the Three Gorges Reservoir (TGR) on river-connected
lakes in the middle region of the Yangtze River, we developed an integrated one-dimensional
(1D)/two-dimensional (2D) coupled hydrodynamic model which covers Yangtze River
from dam site to Datong hydrologic station, Dongting Lake, Poyang Lake and their
main tributaries. On the basis of calibrated and validated the coupled model, we
used actual and unregulated release from the Three Gorges Dam (TGD) as upstream
boundary condition, compared actual releases and the water level of Poyang Lake
to unregulated releases from TGR. The results indicate that dam regulation has changed
the temporal patterns in discharge in the Yangtze River especially in the emptying
stage from May to June and the impoundment stage from September to October. During
the emptying stage the release averagely increased by 3760 m3/s and the lake water
level increased by 0.42m respectively. On the contrary, during the impoundment stage,
the release decreased by 4200m3/s and the lake water level decreased by 0.57m respectively.
But this has limited impacts on the Poyang Lake in normal year .When the Poyang
Lake basin is in extreme dry years, other measures such as building a floodgate
at the lake mouth to regulate the lake water level should be taken.
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Seismic behavior of shallow foundations during major
earthquakes and artificial symmetrical shakes based on a three-dimensional effective
stress analysis
Lu Chih Wei, Lee Hsien Yi, Wu Po Kai*, Kung Gordon Tung-Chin, Chang Bin Yang, Pachori
Kanti, Chaturvedi Shobha and Gargh Shankar
A three dimensional effective stress numerical tool was
used for analyzing dynamic behaviors of shallow foundations. Three shallow foundations
with different dimensions sitting on ground partially consisted of liquefiable soils
exited by symmetrical sine waves with 100gal to 300gal and non- symmetrical shakes
including 1995 Kobe earthquake and 1999 Chi- Chi earthquake. It was found that (1)
the major settlement of the structure was developed during shakes; (2) quantity
of the major settlement was related to the magnitude of shakes and the dynamic soil-
structure interaction; (3) post liquefaction induced settlement occurred during
the dissipation of pore water pressure and the extent of this settlement corresponded
to the weight of the structure; (4) inclination of the structure and its maximum
value was not necessarily proportional to the magnitude of the seismic waves because
of the complexity of the related factors in soil- structure interaction (SSI).
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Identification and early warning method for rock mass
instability
Wang Chunlai
Generally, rock mass is considered to be elastic-brittle-plastic,
the determination and accurate warning of rock mass instability is very difficult.
At present, the warning method for rock mass instability is not established. In
this study, we use Tangent modulus as a foundation and selected the variation tendency
of rock mass instability to build an instability warning method and model. This
model is applied to the 10# ore body of Huize lead-Zinc Mine in China. The warning
results for rock mass instability were obtained. Compared with other evaluation
method, this method shows greater adaptability.
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Triggering mechanism of a rainfall-induced landslide
–a case study
Meen-Wah Gui
There have been many landslides reported around the world
and in Taiwan lately as a result of extreme climate change.It is important to pinpoint
areas with sensitive geological features and to improve current tools for geological
disaster investigation and monitoring because the extreme climate change and the
ongoing orogeny process have significantly increased the frequency of the occurrence
of landslides in these geological sensitive areas. To mitigate landslide problems,
a complete landslide analysis must consider both the mechanical and hydraulic characteristics
of the material of the slope and also include factors such as the topographical
and antecedent weather conditions. This study aims at applying hydro-mechanical
formulation in a numerical analysis to evaluate the triggering mechanism of a landslide
that occurred after three successive typhoons within a period of 20 days. The study
evaluated the location at which the landslide was triggered and compared it with
the results postulated by other studies. It was found that antecedent rainfall has
played an important role in triggering the landslide.
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Accuracy Assessment of Landuse Classification from
Airborne Hyperspectral Imagery fused with LiDAR Data
Sun Woong Kim, Hien Phu La and Yang Dam Eo*
Accurate landuse classification maps show the current
status of natural and manmade objects on the earth’s surface and such information
can be used to monitor the health of forests, contamination of watercourses and
climate change. This paper shows that the classification accuracy of airborne hyperspectral
images is improved when fused with LiDAR data. Two widely used methods—the support
vector machine and segmentation—were tested and both showed an improvement in the
accuracy. To verify the accuracy, a digital cadastral map displaying land categories
by parcel was used as reference data. The study showed classification using fused
data proved to be useful, regardless of the number of classes or the classifier
used for analysis.
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Effect of Strength Anisotropy on Basal Heave of Deep
Excavations
Shi-Fon Su
The reinforcement improvement techniques are used in
deep excavation projects in order to increase the base stability of excavations
in soft clay and to reduce the excavation induced ground movements. The classical
design of an excavation is often based on a limit equilibrium analysis in which
the soil is considered as an isotropic material. However, the anisotropic strength
characteristic of clay reinforced with grout piles is more significant than that
of clay. This paper estimates the effect of strength anisotropy on the base stability
of deep excavation in soft clay with or without ground improvement. Based on upper
bound analysis using anisotropic and isotropic strength criteria, the difference
between the factor of safety against base heave was determined from anisotropic
limit analysis and that determined from isotropic limit analysis can be evaluated.
Careful selection of mobilized strengths used in isotropic limit analysis is important.
For deep excavations in the reinforcement of clay using grout piles, the use of
isotropic strength analysis is capable of determining the factor of safety against
base heave when the isotropic strengths of clay and clay reinforced with grout piles
are based on CKoUC strength and CKoUE strength respectively.
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Impacts of climate change under IPCC RCP scenarios
on streamflow and water quality in the Youngsan Basin, South Korea
Choi Jisun, Park Soyoung, Yeu Yeon, Yoon Hong-Joo, Choi Chuluong and Kim Jinsoo*
This study sought to analyze how changes in climate under
the Representative Concentration Pathways (RCP) scenario affect streamflow and water
quality within the Youngsan River Basin. This study used RCP 4.5 and 8.5 scenarios
with 12.5 km resolution for the Korean Peninsula of a regional climate change model
assuming that the future land use is the same as current land use [2000 Land Use/Land
Cover (LULC) map]. The results from simulations of streamflow, sediment and total
nitrogen (TN) load in the future (2020s, 2040s, 2060s) using the Soil and Water
Assessment Tool (SWAT) model shows that climate change causes very distinctive seasonal
changes in streamflow and water quality. As streamflow, sediment and TN load react
very sensitively to seasonal changes in precipitation, these parameters are predicted
to increase in spring and winter and decrease in summer and autumn. Moreover, water
pollution in the drainage basin is predicted to become a very serious problem because
the inflow of nonpoint source pollution is increasing due to severe rainstorms in
summer and the use of nitrate fertilizer in spring.
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Investigating the Rainfall-Induced Groundwater Variation
and Movement of Highway Slope
Lee Der-Her, Chen Po-Ying*, Wu Jian-Hong, Chang Yu-Cheng and Chang Keng-Feng
Global warming causes significant climate change throughout
the world. Taiwan is located in the western Pacific typhoon path and cannot avoid
the influence of climate change. In response to the change of rainfall patterns
affecting the stability of highway slopes in southwestern Taiwan’s mountainous areas,
the highway slope, which is located in Nan-hua Reservoir catchment, is the research
subject for this study. Typical slopes in the mountainous areas of southern Taiwan
consist of the colluvium at the shallow depth. The data of borehole drilling is
used to understand the stratum distribution underground as well as setting incline
monitoring and a piezometer. In addition, a rain gauge is used to obtain local rainfall
data. According to the study results, the relationship between the rate of groundwater
change and the duration time is expressed as an exponential function. Besides, the
relationship between the groundwater change rate and the accumulated rainfall is
established in this study. Hence, by monitoring the rainfall we can predict the
variation in the amount of groundwater and the groundwater rising rate, enabling
us to determine whether or not the groundwater is close to the highest elevation.
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Study on Seepage Character of Loess Vertical Joint
Luo Yang*, Wang Tie-hang and Liu Xiao-jun
The seepage characteristic of vertical joint in loess
is investigated through field test, theoretical analysis and numerical approach.
It shows that the existence of vertical joint has a strong impact on the seepage
property of loess along the joint direction by comparing the migration of wetting
front in joint and non-joint loess field test. In the initial stage of infiltration,
vertical joint has strong permeability. The infiltration speed of loess in the joint
direction is far greater than that in horizontal direction. As the time goes by,
infiltration speed in joint direction comes to reduce and the vertical joint closed
gradually. Then the joint is simplified by using the parallel plate model and the
permeability coefficient of loess joint has been established. This expression preliminarily
considers the fact that infiltration capacity of joint varies with the volumetric
water content of loess. Subsequently, finite element analysis is conducted on the
migration of wetting front in joint loess using this expression to study for the
seepage character of loess vertical joint and a comparison analysis is made with
non-joint loess. The comparison between numerical calculation result and field test
of joint loess verifies the suitability of this joint expression in describing the
joint infiltration coefficient.
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