Abstract: In this study, shaking table tests are performed to investigate the behavior of excess pore water pressure in different soft soil-foundations of soil-structure interaction (SSI) system. The variation of the behaviors under cycled minor shock is observed. Moreover, The generation and variation mechanism of excess pore water pressure under earthquake excitation in different soft soilfoundations are analyzed and discussed.
Abstract: A laboratory study on the influence of compactive
effort on expansive black cotton specimens treated with up to 8%
ordinary Portland cement (OPC) admixed with up to 8% bagasse ash
(BA) by dry weight of soil and compacted using the energies of the
standard Proctor (SP), West African Standard (WAS) or
“intermediate” and modified Proctor (MP) were undertaken. The
expansive black cotton soil was classified as A-7-6 (16) or CL using
the American Association of Highway and Transportation Officials
(AASHTO) and Unified Soil Classification System (USCS),
respectively. The 7day unconfined compressive strength (UCS)
values of the natural soil for SP, WAS and MP compactive efforts are
286, 401 and 515kN/m2 respectively, while peak values of 1019,
1328 and 1420kN/m2 recorded at 8% OPC/ 6% BA, 8% OPC/ 2% BA
and 6% OPC/ 4% BA treatments, respectively were less than the
UCS value of 1710kN/m2 conventionally used as criterion for
adequate cement stabilization. The soaked California bearing ratio
(CBR) values of the OPC/BA stabilized soil increased with higher
energy level from 2, 4 and 10% for the natural soil to Peak values of
55, 18 and 8% were recorded at 8% OPC/4% BA 8% OPC/2% BA
and 8% OPC/4% BA, treatments when SP, WAS and MP compactive
effort were used, respectively. The durability of specimens was
determined by immersion in water. Soils treatment at 8% OPC/ 4%
BA blend gave a value of 50% resistance to loss in strength value
which is acceptable because of the harsh test condition of 7 days
soaking period specimens were subjected instead of the 4 days
soaking period that specified a minimum resistance to loss in strength
of 80%. Finally An optimal blend of is 8% OPC/ 4% BA is
recommended for treatment of expansive black cotton soil for use as
a sub-base material.
Abstract: The most planted cover crops in the Czech Republic
are mustard (Sinapis alba) and phacelia (Phacelia tanacetifolia
Benth.). A field trial was executed to evaluate root system size (RSS)
in eight varieties of mustard and five varieties of phacelia on two
locations, in three BBCH phases and in two years. The relationship
between RSS and aboveground biomass was inquired. The root
system was assessed by measuring its electric capacity. Aboveground
mass and root samples to be evaluated by means of a digital image
analysis were recovered in the BBCH phase 70. The yield of
aboveground biomass of mustard was always statistically
significantly higher than that of phacelia. Mustard showed a
statistically significant negative correlation between root length
density (RLD) within 10 cm and aboveground biomass weight (r = -
0.46*). Phacelia featured a statistically significant correlation
between aboveground biomass production and nitrate nitrogen
content in soil (r=0.782**).
Abstract: Air quality in Setapak district of Kuala Lumpur was
studied by analysing the rainwater chemical composition using ion
chromatography method. Twelve sampling sites were selected and
120 rainwater samples were collected in the period of 10 weeks. The
results of this study were compared to the earlier published data and
the evaluation showed that the NO3
- ion concentration increased from
0.41 to 3.32 ppm, while SO4
2- ion concentration increased from 0.39
to 3.26 ppm over the past two decades that is mostly due to rapid
urban development of the city. However, it was found that the
chemical composition for both residential and industrial areas does
not have significant difference. Most of the rainwater samples
showed alkaline pH (pH > 5.6). The possible factors for such alkaline
pH in rainwater samples are assumed to be the marine sources,
biomass burning and alkaline character of soil particles.
Abstract: Corrosion of metallic water pipelines buried below
ground surface is a function of the nature of the surrounding soil and
groundwater. This gives the importance of knowing the physical and
chemical characteristics of the pipe-s surrounding environment. The
corrosion of externally – unprotected metallic water pipelines,
specially ductile iron pipes, in localities with aggressive soil
conditions is becoming a significant problem. Anticorrosive
protection for metallic water pipelines, their fittings and accessories
is very important, because they may be attached by corrosion with
time. The tendency of a metallic substrate to corrode is a function of
the surface characteristics of the metal and of the metal/protective
film interface, the physical, electrical and electrochemical properties
of the film, and the nature of the environment in which the pipelines
system is placed. In this work the authors have looked at corrosion
problems of water pipelines and their control. The corrosive
properties of groundwater and soil environments are reviewed, and
parameters affecting corrosion are discussed. The purpose of this
work is to provide guidelines for materials selection in water and soil
environments, and how the water pipelines can be protected against
metallic corrosion.
Abstract: This work investigated the phenology of Parah tree
(Elateriospermum tapos) using the General Purpose Atmosphere
Plant Soil Simulator (GAPS model) to determine the amount of Plant
Available Water (PAW) in the soil. We found the correlation
between PAW and the timing of budburst and flower burst at Khao
Nan National Park, Nakhon Si Thammarat, Thailand. PAW from the
GAPS model can be used as an indicator of soil water stress. The low
amount of PAW may lead to leaf shedding in Parah trees.
Abstract: The soil ecology of the organic and mineral soil layers
of laurel-leaved and Cryptomeria japonica forest in the Kasuga-yama
Hill Primeval Forest (Nara, Japan) was assessed. The number of
bacteria obtained by the dilution plate count method was less than
0.05% of those counted by the direct microscopic count. We therefore
found that forest soil contains large numbers of non-culturable
bacteria compared with agricultural soils. The numbers of bacteria and
fungi obtained by both the dilution plate count and the direct
microscopic count were larger in the deeper horizons (F and H) of the
organic layer than in the mineral soil layer. This suggests that active
microbial metabolism takes place in the organic layer. The numbers of
bacteria and the length of fungal hyphae obtained by the direct count
method were greater in the H horizon than in the F horizon. The direct
microscopic count revealed numerous non-culturable bacteria and
fungi in the soil. The ratio of fungal to bacterial biomass was lower in
the laurel-leaved forest soil. The fungal biomass was therefore
relatively low in the laurel-leaved forest soil due to differences in
forest vegetation.
Abstract: In studying the possibility of using plants as
rhizoremediators, barley and grass mixture which showed resistance
to various concentrations of oil were selected. The minimum
inhibitory effect of oil on these plants by morphological parameters
such as survival of plants, length and biomass of shoot and root
compared with the control was showed. In determining physiological
parameters, a slight decrease in the number of chlorophyll a and b in
the leaves of plants was noted. The differences in the ratio of the total
surface of the roots to the work surface with the growth of plants in
soil with oil in the study of adsorption of the root surface were
showed.
Abstract: The Chichiawan stream in the Wulin catchment in
Taiwan is the natural habitat of Formosan landlocked salmon. Human
and agriculture activities gradually worsen water quality and impact
the fish habitat negatively. To protect and manage Formosan
landlocked salmon habitat, it is important to understand a variety
land-uses affect on the watershed responses to storms. This study
discusses watershed responses to the dry-day before a storm event and
a variety of land-uses in the Wulin catchment. Under the land-use
planning in the Wulin catchment, the peak flows during typhoon
events do not have noticeable difference. However, the nutrient
exports can be highly reduced under the strategies of restraining
agriculture activities. Due to the higher affinity of P for soil than that
of N, the exports of TN from overall Wuling catchment were much
greater than Ortho-P. Agriculture mainly centralized in subbasin A,
which is the important source of nutrients in nonpoint source discharge.
The subbasin A supplied about 26% of the TN and 32% of the Ortho-P
discharge in 2004, despite the fact it only covers 19% area of the
Wuling catchment. The subbasin analysis displayed that the
agricultural subbasin A exports higher nutrients per unit area than
other forest subbasins. Additionally, the agricultural subbasin A
contributed a higher percentage to total Ortho-P exports compares to
TN. The results of subbasin analysis might imply the transport of
Ortho-P was similar to the particulate matter which was mainly
influenced by the runoff and affected by the desorption from soil
particles while the TN (dominated as nitrate-N) was mainly influenced
by base-flow.
Abstract: Heavy metal pollution is an environmental concern.
Phytoremediation is a low-cost, environmental-friendly approach to
solve this problem. Mustard has the potential in reducing heavy metal
contents in soils. Among mustard (Brassica juncea (L.) Czern &
Coss) genotypes in Sri Lanka, accessions 7788, 8831 and 5088 give
significantly a high yield. Therefore, present study was conducted to
quantify the phytoextractive potential among these local mustard
accessions and to assess the interaction of heavy metals, Pb, Co, Mn
on phytoextraction. A pot experiment was designed with acid washed
sand (quartz) and a series of heavy metal solutions of 0, 25, 50, 75
and 100 μg/g. Experiment was carried out with factorial
experimental design. Mustard accessions were tolerant to heavy
metals and could be successfully used in removal of Pb, Co and Mn
and they are capable of accumulating significant quantities of heavy
metals in vegetative and reproductive organs. The order of the
accumulative potential of Pb, Co and Mn in mustard accessions is,
root > shoot >seed.
Abstract: The heavy metal contamination of the technogenous
sediments and soils at the investigated dump-field show irregular
planar distribution. Also the heavy metal content in the surface water,
drainage water and in the groundwater was studied both in the dry as
well as during the rainy periods. The cementation process causes
substitution of iron by copper. Natural installation and development
of plant species was observed at the old mine waste dumps, specific
to the local chemical conditions such as low content of essential
nutrients and high content of heavy metals. The individual parts of
the plant tissues (roots, branches/stems, leaves/needles, flowers/
fruits) are contaminated by heavy metals and tissues are damaged
differently, respectively.
Abstract: An evaluation of the PCBs residues in the surface soils from Bacninh, Vietnam was carried out. Sixty representative soil samples were collected from the centre of Bacninh and three surrounding districts. The analyzed results indicated the wide extent of contamination of total PCBs in Bacninh. In industrial and urban zones, total PCBs concentrations ranged from ranged from
Abstract: The objectives of this study are to determine the
effects of soil cover type on characteristics of leachates generated
from landfill lysimeters. Four lysimeters with diameter and height
of 0.15 and 3.00 m, respectively, were prepared. Three lysimeters
were filled with municipal waste and three different cover soil types
i.e. sandy loam soil, silty loam soil and clay soil while another
lysimeter was filled solely with municipal waste. The study was
conducted in the rainy season. Leachate quantities were measured
every day and leachate characteristics were determined once a week.
The cumulative leachate quantity from the lysimeter filled solely
with municipal waste was found to be around 27% higher than the
lysimeters using cover soils. There were no any differences of the
cumulative leachate amounts generated from the lysimeters using
three types of soils. The comparison of the total mass of pollutants
generated from all lysimeters showed that the lysimeter filled solely
with municipal waste generated the maximum quantities of
pollutants. Among the lysimeters using different types of soils, the
lysimeter using sandy loam soil generated the lowest amount of most
of pollutants, compared with the lysimeters using silty loam and clay
soils. It can be concluded that in term of pollutant attenuation in the
leachate, a sandy loam is the most suitable soil to be used as a cover
soil in the landfill.
Abstract: This experiment discusses the effects of fracture
parameters such as depth, length, width, angle and the number of the
fracture to the conductance properties of laterite using the DUK-2B
digital electrical measurement system combined with the method of
simulating the fractures. The results of experiment show that the
changes of fracture parameters produce effects to the conductance
properties of laterite. There is a clear degressive period of the
conductivity of laterite during increasing the depth, length, width, or
the angle and the quantity of fracture gradually. When the depth of
fracture exceeds the half thickness of the soil body, the conductivity of
laterite shows evidently non-linear diminishing pattern and the
amplitude of decrease tends to increase. The length of fracture has
fewer effects than the depth to the conductivity. When the width of
fracture reaches some fixed values, the change of the conductivity is
less sensitive to the change of the width, and at this time, the
conductivity of laterite maintains at a stable level. When the angle of
fracture is less than 45°, the decrease of the conductivity is more
clearly as the angle increases. But when angle is more than 45°,
change of the conductivity is relatively gentle as the angle increases.
The increasing quantity of the fracture causes the other fracture
parameters having great impact on the change of conductivity. When
moisture content and temperature were unchanged, depth and angle of
fractures are the major factors affecting the conductivity of laterite
soil; quantity, length, and width are minor influencing factors. The
sensitivity of fracture parameters affect conductivity of laterite soil is:
depth >angles >quantity >length >width.
Abstract: Microbial oil was produced by soil isolated
oleaginous yeast YU5/2 in flask-batch fermentation. The yeast was
identified by molecular genetics technique based on sequence
analysis of the variable D1/D2 domain of the large subunit (26S)
ribosomal DNA and it was identified as Torulaspora globosa. T.
globosa YU5/2 supported maximum values of 0.520 g/L/d, 0.472 g
lipid/g cells, 4.16 g/L, and 0.156 g/L/d for volumetric lipid
production rate, and specific yield of lipid, lipid concentration, and
specific rate of lipid production respectively, when culture was
performed in nitrogen-limiting medium supplemented with 80g/L
glucose. Among the carbon sources tested, maximum cell yield
coefficient (YX/S, g/L), maximum specific yield of lipid (YP/X, g
lipid/g cells) and volumetric lipid production rate (QP, g/L/d) were
found of 0.728, 0.237, and 0.619, respectively, using sweet potato
tubers hydrolysates as carbon source.
Abstract: Integral Abutment Bridges (IAB) are defined as
simple or multiple span bridges in which the bridge deck is cast
monolithically with the abutment walls. This kind of bridges are
becoming very popular due to different aspects such as good
response under seismic loading, low initial costs, elimination of
bearings, and less maintenance. However the main issue related to
the analysis of this type of structures is dealing with soil-structure
interaction of the abutment walls and the supporting piles. Various
soil constitutive models have been used in studies of soil-structure
interaction in this kind of structures by researchers. This paper is an
effort to review the implementation of various finite elements model
which explicitly incorporates the nonlinear soil and linear structural
response considering various soil constitutive models and finite
element mesh.
Abstract: Phytotoxicity of Daphne gnidium L. was evaluated
through the effect of incorporating leaves, stems and roots biomass
into soil (at 12.5, 25, 50g/Kg) and irrigation by their aqueous extracts
(50g/L), on the growth of two crops (Lactuca sativa L. and Raphanus
sativus L.) and two weeds (Peaganum harmala L. and Scolymus
maculatus L.). Results revealed a perceptible phytotoxic effect which
increased with dose and concentration. At the highest dose, roots and
leaves residues was the most toxic and caused total inhibition
respectively, for lettuce and thistle seedling growth. Irrigation with
aqueous extracts of D. gnidium different organs decreased also
seedlings length of all test species. Stems extract was more inhibitor
on thistle than peganum seedling growth; it induced a significant
reduction of 80% and 67%, for, respectively, roots and shoots.
Results of the present study suggest that different organs of D.
gnidium could be exploited in the management of agro-ecosystems.
Abstract: This paper focuses on the development of bond graph
dynamic model of the mechanical dynamics of an excavating mechanism
previously designed to be used with small tractors, which are
fabricated in the Engineering Workshops of Jomo Kenyatta University
of Agriculture and Technology. To develop a mechanical dynamics
model of the manipulator, forward recursive equations similar to
those applied in iterative Newton-Euler method were used to obtain
kinematic relationships between the time rates of joint variables
and the generalized cartesian velocities for the centroids of the
links. Representing the obtained kinematic relationships in bondgraphic
form, while considering the link weights and momenta as
the elements led to a detailed bond graph model of the manipulator.
The bond graph method was found to reduce significantly the number
of recursive computations performed on a 3 DOF manipulator for a
mechanical dynamic model to result, hence indicating that bond graph
method is more computationally efficient than the Newton-Euler
method in developing dynamic models of 3 DOF planar manipulators.
The model was verified by comparing the joint torque expressions
of a two link planar manipulator to those obtained using Newton-
Euler and Lagrangian methods as analyzed in robotic textbooks. The
expressions were found to agree indicating that the model captures
the aspects of rigid body dynamics of the manipulator. Based on
the model developed, actuator sizing and valve sizing methodologies
were developed and used to obtain the optimal sizes of the pistons
and spool valve ports respectively. It was found that using the pump
with the sized flow rate capacity, the engine of the tractor is able to
power the excavating mechanism in digging a sandy-loom soil.
Abstract: A passive system "Qanat" is collection of some
underground wells. A mother-well was dug in a place far from the
city where they could reach to the water table maybe 100 meters
underground, they dug other wells to direct water toward the city,
with minimum possible gradient. Using the slope of the earth they
could bring water close to the surface in the city. The source of water
or the appearance of Qanat, land slope and the ownership lines are
the important and effective factors in the formation of routes and the
segment division of lands to the extent that making use of Qanat as
the techniques of extracting underground waters creates a channel of
routes with an organic order and hierarchy coinciding the slope of
land and it also guides the Qanat waters in the tradition texture of salt
desert and border provinces of it. Qanats are excavated in a specified
distinction from each other. The quantity of water provided by
Qanats depends on the kind of land, distance from mountain,
geographical situation of them and the rate of water supply from the
underground land. The rate of underground waters, possibility of
Qanat excavation, number of Qanats and rate of their water supply
from one hand and the quantity of cultivable fertile lands from the
other hand are the important natural factors making the size of cities.
In the same manner the cities with several Qanats have multi central
textures. The location of cities is in direct relation with land quality,
soil fertility and possibility of using underground water by excavating
Qanats. Observing the allowable distance for Qanat watering is a
determining factor for distance between villages and cities.
Topography, land slope, soil quality, watering system, ownership,
kind of cultivation, etc. are the effective factors in directing Qanats
for excavation and guiding water toward the cultivable lands and it
also causes the formation of different textures in land division of
farming provinces. Several divisions such as orderly and wide, inorderly,
thin and long, comb like, etc. are the introduction to organic
order. And at the same time they are complete coincidence with
environmental conditions in the typical development of ecological
architecture and planning in the traditional cities and settlements
order.
Abstract: All over the world, including the Middle and East
European countries, sustainable tillage and sowing technologies are
applied increasingly broadly with a view to optimising soil resources,
mitigating soil degradation processes, saving energy resources,
preserving biological diversity, etc. As a result, altered conditions of
tillage and sowing technological processes are faced inevitably. The
purpose of this study is to determine the seedbed topsoil hardness
when using a combined sowing coulter in different sustainable tillage
technologies. The research involved a combined coulter consisting
of two dissected blade discs and a shoe coulter. In order to determine
soil hardness at the seedbed area, a multipenetrometer was used. It
was found by experimental studies that in loosened soil, a combined
sowing coulter equally suppresses the furrow bottom, walls and soil
near the furrow; therefore, here, soil hardness was similar at all
researched depths and no significant differences were established. In
loosened and compacted (double-rolled) soil, the impact of a
combined coulter on the hardness of seedbed soil surface was more
considerable at a depth of 2 mm. Soil hardness at the furrow bottom
and walls to a distance of up to 26 mm was 1.1 MPa. At a depth of 10
mm, the greatest hardness was established at the furrow bottom. In
loosened and heavily compacted (rolled for 6 times) soil, at a depth
of 2 and 10 mm a combined coulter most of all compacted the furrow
bottom, which has a hardness of 1.8 MPa. At a depth of 20 mm, soil
hardness within the whole investigated area varied insignificantly and
fluctuated by around 2.0 MPa. The hardness of furrow walls and soil
near the furrow was by approximately 1.0 MPa lower than that at the
furrow bottom