Abstract: Ocean current is always available around the
surrounding of SHELL Sabah Water Platform and data are collected
every 10 minutes, 24 hours a day, for a period of 365 days. Due to
low current speed, conventional hydrokinetic power generation is not
feasible, thus leading to the study of low current enabled vortex
induced vibration power generation application. In this case, the
design of a vortex induced vibration application is studied to obtain
an optimum design for the VIV oscillator. Power output is then
determined to study the feasibility of the VIV application in low
current condition.
Abstract: A repairable mechanical system (as agricultural
tractor) is subject to deterioration or repeated failure and needs a
repair shops and also operator’s capability for the repair and
maintenance operations. Data are based on field visits and interviews
with 48MF 285 tractor operators from 14 villages collected in north
of Khouzestan province. The results showed that most operators were
lack the technical skill to service and repair tractors due to
insufficient training, specific education and work experience.
Inadequate repair and maintenance facilities, such as workshops,
mechanics and spare parts depots cause delays in repair work in the
survey areas. Farmers do not keep accurate service records and most
of them disregard proper maintenance and service of their tractors,
such as changing engine oil without following the manufacturer’s
recommendations. Since, Repair and maintenance facilities should be
established in village areas to guarantee timely repair in case of
breakdowns and to make spare parts available at low price. The
operators should keep service records accurately and adhere to
maintenance and service schedules according to the manufacturer’s
instructions. They should also be encouraged to do the service and
maintain their tractors properly.
Abstract: By enhancing the applicatıon of grounds for
establishment and due to the lack of appropriate sites, engineers
attempt to seek out a new method to reduce the weakness of soils. İn
aspect of economic situation, various ways have been used to
decrease the weak grounds. Because of the rapid development of
infrastructural facilities, spreading the construction operation is an
obligation. Furthermore, in various sites with the really bad soil
situation, engineers have considered obvious problems. One of the
most essential ways for developing the weak soils is stone column.
Obviously, the method was introduced in France in 1830 to improve
a native soil initially. Stone columns have an expanding range of
usage in different rough foundation sites all over the world to
increase the bearing capacity, to reduce the whole and differential
settlements, to enhance the rate of consolidation, to stabilize slopes
stability of embankments and to increase the liquefaction resistance
as well. A recent procedure called installing vertical nails along the
round stone columns in order to make better the performance of
considered columns is offered. Moreover, thanks to the enhancing the
nail diameter, number and embedment nail depth, the positive points
of vertical circumferential nails increases. Based on the result of this
study, load caring capacity will be develop with enhancing the length
and the power of reinforcements in vertical encasement stone column
(CESC). In this study, the main purpose is comparing two methods of
stone columns (installed a nail surrounding the stone columns and
using geogrid on clay) for enhancing the bearing capacity, decreasing
the whole and various settlements.
Abstract: Structure-borne noise is an important aspect of
offshore platform sound field. It can be generated either directly by
vibrating machineries induced mechanical force, indirectly by the
excitation of structure or excitation by incident airborne noise.
Therefore, limiting of the transmission of vibration energy
throughout the offshore platform is the key to control the structureborne
noise. This is usually done by introducing damping treatment
to the steel structures. Two types of damping treatment using onboard
are presented. By conducting a Statistical Energy Analysis
(SEA) simulation on a jack-up rig, the noise level in the source room,
the neighboring rooms, and remote living quarter cabins are
compared before and after the damping treatments been applied. The
results demonstrated that, in the source neighboring room and living
quarter area, there is a significant noise reduction with the damping
treatment applied, whereas in the source room where air-borne sound
predominates that of structure-borne sound, the impact is not
obvious. The conclusion on effective damping treatment in the
offshore platform is made which enable acoustic professionals to
implement noise control during the design stage for offshore crews’
hearing protection and habitant comfortability.
Abstract: There have been rigorous research and development
of unmanned aerial vehicles in the field of search and rescue (SAR)
operation recently. UAVs reduce unnecessary human risks while
assisting rescue efforts through aerial imagery, topographic mapping
and emergency delivery. The application of UAVs in offshore and
nearshore marine SAR missions is discussed in this paper. Projects
that integrate UAV technology into their systems are introduced to
highlight the great advantages and capabilities of UAVs. Scenarios
where UAVs could provide invaluable assistance are also suggested.
Abstract: Mobil Producing Nigeria Unlimited (MPNU), a
subsidiary of ExxonMobil and the highest crude oil & condensate
producer in Nigeria has its operational base and an oil terminal, the
Qua Iboe terminal (QIT) located at Ibeno, Nigeria. Other oil
companies like Network Exploration and Production Nigeria Ltd,
Frontier Oil Ltd; Shell Petroleum Development Company Ltd; Elf
Petroleum Nigeria Ltd and Nigerian Agip Energy, a subsidiary of the
Italian ENI E&P operate onshore, on the continental shelf and in deep
offshore of the Atlantic Ocean, respectively with the coastal waters of
Ibeno, Nigeria as the nearest shoreline. This study was designed to
delineate the oil-polluted sites in Ibeno, Nigeria using
microbiological and physico-chemical characterization of soils,
sediments and ground and surface water samples from the study area.
Results obtained revealed that there have been significant recent
hydrocarbon inputs into this environment as observed from the high
counts of hydrocarbonoclastic microorganisms in excess of 1% at all
the stations sampled. Moreover, high concentrations of THC, BTEX
and heavy metals contents in all the samples analyzed corroborate the
high recent crude oil input into the study area. The results also
showed that the pollution of the different environmental media
sampled were of varying degrees, following the trend: ground water
> surface water > sediments > soils.
Abstract: The sea waves carry thousands of GWs of power
globally. Although there are a number of different approaches to
harness offshore energy, they are likely to be expensive, practically
challenging, and vulnerable to storms. Therefore, this paper considers
using the near shore waves for generating mechanical and electrical
power. It introduces two new approaches, the wave manipulation and
using a variable duct turbine, for intercepting very wide wave fronts
and coping with the fluctuations of the wave height and the sea level,
respectively. The first approach effectively allows capturing much
more energy yet with a much narrower turbine rotor. The second
approach allows using a rotor with a smaller radius but captures
energy of higher wave fronts at higher sea levels yet preventing it
from totally submerging. To illustrate the effectiveness of the first
approach, the paper contains a description and the simulation results
of a scale model of a wave manipulator. Then, it includes the results
of testing a physical model of the manipulator and a single duct, axial
flow turbine in a wave flume in the laboratory. The paper also
includes comparisons of theoretical predictions, simulation results,
and wave flume tests with respect to the incident energy, loss in wave
manipulation, minimal loss, brake torque, and the angular velocity.
Abstract: In contrast with literal meaning of nano, researchers
have been achieved mega adventures in this area and every day more
nanomaterials are being introduced to the market. After long time
application of fossil-based plastics, nowadays accumulation of their
waste seems to be a big problem to the environment. On the other
hand, mankind has more attention to safety and living environment.
Replacing common plastic packaging materials with degradable ones
that degrade faster and convert to non-dangerous components like
water and carbon dioxide have more attractions; these new materials
are based on renewable and inexpensive sources of starch and
cellulose. However, the functional properties of them do not suitable
for packaging. At this point, nanotechnology has an important role.
Utilizing of nanomaterials in polymer structure will improve
mechanical and physical properties of them; nanocrystalline cellulose
(NCC) has this ability. This work has employed a chemical method to
produce NCC and starch bio nanocomposite containing NCC. X-Ray
Diffraction technique has characterized the obtained materials.
Results showed that applied method is a suitable one as well as
applicable one to NCC production.
Abstract: The fatigue life of tubular joints commonly found in
offshore industry is not only dependent on the value of hot-spot stress
(HSS), but is also significantly influenced by the through-thethickness
stress distribution characterized by the degree of bending
(DoB). The determination of DoB values in a tubular joint is essential
for improving the accuracy of fatigue life estimation using the stresslife
(S–N) method and particularly for predicting the fatigue crack
growth based on the fracture mechanics (FM) approach. In the
present paper, data extracted from finite element (FE) analyses of
tubular KT-joints, verified against experimental data and parametric
equations, was used to investigate the effects of geometrical
parameters on DoB values at the crown 0°, saddle, and crown 180°
positions along the weld toe of central brace in tubular KT-joints
subjected to axial loading. Parametric study was followed by a set of
nonlinear regression analyses to derive DoB parametric formulas for
the fatigue analysis of KT-joints under axial loads. The tubular KTjoint
is a quite common joint type found in steel offshore structures.
However, despite the crucial role of the DoB in evaluating the fatigue
performance of tubular joints, this paper is the first attempt to study
and formulate the DoB values in KT-joints.
Abstract: Super steel materials play a vital role in the
construction and fabrication of structural, piping and pipeline
components. In assuring the integrity of onshore and offshore
operating systems, they enable life cycle costs to be minimized. In
this context, Duplex stainless steel (DSS) material related welding on
constructions and fabrications plays a significant role in maintaining
and assuring integrity at an optimal expenditure over the life cycle of
production and process systems as well as associated structures. In
DSS welding, factors such as gap geometry, shielding gas supply
rate, welding current, and type of the welding process are vital to the
final joint performance. Hence, an experimental investigation has
been performed using an engineering robust design approach
(ERDA) to investigate the optimal settings that generate optimal
super DSS (i.e. UNS S32750) joint performance. This manuscript
illustrates the mathematical approach and experimental design,
optimal parameter settings and results of the verification experiment.
Abstract: Ibeno, Nigeria hosts the operational base of Mobil
Producing Nigeria Unlimited (MPNU), a subsidiary of ExxonMobil
and the current highest oil & condensate producer in Nigeria. Besides
MPNU, other oil companies operate onshore, on the continental shelf
and deep offshore of the Atlantic Ocean in Ibeno, Nigeria. This study
was designed to delineate oil polluted sites in Ibeno, Nigeria using
geophysical methods of electrical resistivity (ER) and ground
penetrating radar (GPR). Results obtained revealed that there have
been hydrocarbon contaminations of this environment by past crude
oil spills as observed from high resistivity values and GPR profiles
which clearly show the distribution, thickness and lateral extent of
hydrocarbon contamination as represented on the radargram reflector
tones. Contaminations were of varying degrees, ranging from slight
to high, indicating levels of substantial attenuation of crude oil
contamination over time. Moreover, the display of relatively lower
resistivities of locations outside the impacted areas compared to
resistivity values within the impacted areas and the 3-D Cartesian
images of oil contaminant plume depicted by red, light brown and
magenta for high, low and very low oil impacted areas, respectively
confirmed significant recent pollution of the study area with crude
oil.
Abstract: The performance and analysis of speech recognition
system is illustrated in this paper. An approach to recognize the
English word corresponding to digit (0-9) spoken by 2 different
speakers is captured in noise free environment. For feature extraction,
speech Mel frequency cepstral coefficients (MFCC) has been used
which gives a set of feature vectors from recorded speech samples.
Neural network model is used to enhance the recognition
performance. Feed forward neural network with back propagation
algorithm model is used. However other speech recognition
techniques such as HMM, DTW exist. All experiments are carried
out on Matlab.
Abstract: Experimental & numeral study of temperature
distribution during milling process, is important in milling quality
and tools life aspects. In the present study the milling cross-section
temperature is determined by using Artificial Neural Networks
(ANN) according to the temperature of certain points of the work
piece and the point specifications and the milling rotational speed of
the blade. In the present work, at first three-dimensional model of the
work piece is provided and then by using the Computational Heat
Transfer (CHT) simulations, temperature in different nods of the
work piece are specified in steady-state conditions. Results obtained
from CHT are used for training and testing the ANN approach. Using
reverse engineering and setting the desired x, y, z and the milling
rotational speed of the blade as input data to the network, the milling
surface temperature determined by neural network is presented as
output data. The desired points temperature for different milling
blade rotational speed are obtained experimentally and by
extrapolation method for the milling surface temperature is obtained
and a comparison is performed among the soft programming ANN,
CHT results and experimental data and it is observed that ANN soft
programming code can be used more efficiently to determine the
temperature in a milling process.
Abstract: In this letter, we explore exact solutions for the
Horava-Lifshitz gravity. We use of an extension of this theory with
first order dynamical lapse function. The equations of motion have
been derived in a fully consistent scenario. We assume that there
are some spherically symmetric families of exact solutions of this
extended theory of gravity. We obtain exact solutions and investigate
the singularity structures of these solutions. Specially, an exact
solution with the regular horizon is found.
Abstract: In order to better understand the long term
implications of the grout wear failure mode in large-diameter plainsided
grouted connections, a numerical model has been developed
and calibrated that can take advantage of existing operational plant
data to predict the wear accumulation for the actual load conditions
experienced over a given period, thus limiting the requirement for
expensive monitoring systems. This model has been derived and
calibrated based on site structural condition monitoring (SCM) data
and supervisory control and data acquisition systems (SCADA) data
for two operational wind turbine generator substructures afflicted
with this challenge, along with experimentally derived wear rates.
Abstract: In this paper, the influence of upstream structures on the flow patternaround and inside the wind-catcher is experimentally investigated by smoke flow visualization techniques. Wind-catchers are an important part of natural ventilation in residential buildings or public places such as shopping centers, libraries, etc. Wind-catchers might be also used in places of high urban densities; hence their potential to provide natural ventilation is dependent on the presence of upstream structures. In this study, the two-sided wind-catcher model was based on a real wind-catcher observed in the city of Yazd, Iran. The present study focuses on the flow patterns around and inside the isolated two-sided wind-catcher, and on a two-sided wind-catcher in the presence of an upstream structure. The results show that the presence of an upstream structure influences the airflow pattern force and direction. Placing a high upstream structure reverses the airflow direction inside the wind-catcher.
Abstract: The presence of endocrine-disrupting compounds,
such as bisphenol A (BPA), in the environment can cause serious
health problems. However, there are controversial opinions. This
study investigated the reproductive, metabolic, oxidative and
immunologic-disrupting effects of bisphenol A in male rabbits.
Rabbits were divided into five groups. The first four rabbit groups
were administered oral BPA (1, 10, 50, or 100 mg/kg/day) for ten
weeks. The fifth group was administered corn oil as the vehicle. BPA
significantly decreased serum testosterone, estradiol and the free
androgen index (FAI) and significantly increased sex hormone
binding globulin (SHBG) compared with the placebo group. The
higher doses of BPA showed a significant decrease in follicular
stimulating hormone (FSH) and luteinizing hormone (LH). A
significant increase in blood glucose levels was identified in the BPA
groups. The non-significant difference in insulin levels is a novel
finding. The cumulative testicular toxicity of BPA was clearly
demonstrated by the dose-dependent decrease in absolute testes
weight, primary measures of semen quality and a significant increase
in testicular malonaldehyde (MDA). Moreover, BPA significantly
decreased total antioxidant capacity (TAC) and significantly
increased immunoglobulin G (IgG) at the highest concentration. Our
results suggest that BPA, especially at higher doses, is associated
with many adverse effects on metabolism, oxidative stress, immunity,
sperm quality and markers of androgenic action.
Abstract: In new energy development, wind power has boomed.
It is due to the proliferation of wind parks and their operation in
supplying the national electric grid with low cost and clean resources.
Hence, there is an increased need to establish a proactive
maintenance for wind turbine machines based on remote control and
monitoring. That is necessary with a real-time wireless connection in
offshore or inaccessible locations while the wired method has many
flaws. The objective of this strategy is to prolong wind turbine
lifetime and to increase productivity. The hardware of a remote
control and monitoring system for wind turbine parks is designed. It
takes advantage of GPRS or Wi-Max wireless module to collect data
measurements from different wind machine sensors through IP based
multi-hop communication. Computer simulations with Proteus ISIS
and OPNET software tools have been conducted to evaluate the
performance of the studied system. Study findings show that the
designed device is suitable for application in a wind park.
Abstract: In this paper the effect of wall waviness of side walls
in a two-dimensional wavy enclosure is numerically investigated.
Two vertical wavy walls and straight top wall are kept isothermal and
the bottom wall temperature is higher and spatially varying with
cosinusoidal temperature distribution. A computational code based on
Finite-volume approach is used to solve governing equations and
SIMPLE method is used for pressure velocity coupling. Test is
performed for several different numbers of undulations. The Prandtl
number was kept constant and the Ra number denotes that the flow is
laminar. Temperature and velocity fields are determined. Therefore,
according to the obtained results a correlation is proposed for average
Nusselt number as a function of number of side wall waves. The
results indicate that the Nusselt number is highly affected by number
of waves and increasing it decreases the wavy walls Nusselt number;
although the Nusselt number is not highly affected by surface
waviness when the number of undulations is below one.
Abstract: The global demand for continuous and eco-friendly
renewable energy as alternative to fossils fuels is large and ever
growing in nowadays. This paper will focus on capability of Vortex
Induced Vibration (VIV) phenomenon in generating alternative
energy for offshore platform application. In order to maximize the
potential of energy generation, the effects of lock in phenomenon and
different geometries of cylinder were studied in this project. VIV is
the motion induced on bluff body which creates alternating lift forces
perpendicular to fluid flow. Normally, VIV is unwanted in order to
prevent mechanical failure of the vibrating structures. But in this
project, instead of eliminating these vibrations, VIV will be exploited
to transform these vibrations into a valuable resource of energy.