Computer Simulation of Current Forces on Motion of Floating Production Storage and Offloading in Irregular Waves

This paper presents the effect of current forces on the motion of forces on Floating Production Storage and Offloading (FPSO) in irregular waves. The objective of this research is to compute the motion of FPSO in irregular waves by time domain simulation including the effect of current forces. A study is made on the slowly varying oscillations of a moored single body system in a current and waves. Linear potential theory is used to describe the fluid motion, and three-dimensional source distribution techniques are applied to obtain the hydrodynamic forces and transfer function of the wave exciting forces. OCIMF (1994) data are used for estimation of the current forces. The non-linear time domain simulations have been carried out in irregular waves. Based on it, slowly varying motion responses are examined including the effect of the current forces. Several environmental conditions, such as the current angle of attack, current velocity, significant wave height and mean wave period are considered, which may significantly affect FPSO motion in surge, sway and yaw moments. It is found that the effect of current forces is quite significant when the current velocity is increased. In this simulation, while the current velocity is increased to 3.0 meter/seconds, the impact on FPSO motion is quite significant, which should be taken into consideration from the point of view of safety, failure of mooring systems, operating responses and the dynamic positioning of the FPSO

The Effect of Shielding Gas Flow Rate on Fiber Laser Welding of Boron Steel

During laser welding process, the ionized metal vapor from keyhole surrounding by molten metal mixes with the shielding gas and forms a plasma plume over the molten pool. The small amount of plasma plume is needed to react with molten pool by enhancing the absorption of laser energy thus increase the penetration. However, high amount of plasma will absorb the beam energy and this could decreases the penetration depth. The small wavelength of laser beam such as fiber laser, reported has less influence to plasma plume compared to bigger wavelength such as CO2 laser. However, even though using small wavelength laser, the laser beam with welding speed below 17mm/s had to go through the plasma plume over the molten pool. The suppression of plasma plume is highly influenced by shielding gas setup and flow rate. In this study, the effect of shielding gas flow rate (Argon) on CW and PW mode on low power fiber laser welding of Boron steel (22MnB5) was investigated. The observation of welding surface, width and depth were carried out. The width and depth pattern of CW and PW were slightly different. The range of 10-20L/min shows the widest width and 15L/min shows the deepest penetration for both welding mode

Jatropha Biofuel Industry: The Challenges

Considering environmental issues and to reduce dependency on fossil fuel many countries have politicized to replenish fossil fuel demand from renewable sources. Citing the potential of Jatropha mostly without any scientific and technological backup, it is believed to be one of the most suitable biofuel candidates. Huge grants were released by many projects for huge plantation of Jatropha (millions of hectares). Unfortunately, there has been no significant progress, and Jatropha did not contribute much in the energy scenario. Unavailability of high-yielding cultivar, large-scale plantation without the evaluation of the planting materials, knowledge gap and basic research gap seem to be the main reasons for failure. Thus, the production of Jatropha as a biofuel has been confronted with various challenges such as production, oil extraction, conversion and also its use as a sustainable biofuel. In this chapter, we disclose the challenges and possible remedy for the contribution in the biofuel industry

A cause of communication failure in managing industrialized building system (IBS) projects : a perspective view from project managers

An effective communication process is an important element in distributing information to various project teams. The previous study demonstrates the importance of communication in the project management process in order to encourage project delivery processes successfully. Unfortunately, the issue of communication still dominates Industrialization Building System (IBS) because the project development process are still based on traditional methods. This research aims to explore the cause of communication challenges between construction players in managing IBS projects. The research methodology implemented for this paper was a semi-structured interview approach used to investigate the communication problem. Five experienced project managers were chosen from across the industry. The findings of this study are valuable for improving the communication level of project teams, which will indirectly increase the level of the IBS project delivery process and strengthen team integration on IBS projects in Malaysia

Development of combined vector and torque control methods for independent two induction motor drives

Many applications use two or more motors operating in parallel configuration by using one variable speed drive. This system is able to control these multiple motors at the same desired motor speed operation which provide advantages in terms of components and cost reduction. However, the system is not able to control each motor separately if it is desired to operate at different speeds and it also cannot withstand the load disturbance. To address this problem, the design of combined Vector Control-Direct Torque Control (DTC) methods is proposed and their performance is investigated for the case of independent controlled two induction motors fed by single Five Leg Inverter (FLI) method. Double Zero Sequence (DZS) Injection Method Space Vector Pulse Width Modulation (SVPWM) scheme is used for the FLI. Simulation results from the Simulink/Matlab that verify the validity of the method are also included. The results show the ability of the proposed method to control motor speed independently under forward-reverse step speed command and load disturbance condition

Design and development of automatic inner mirror endurance test system

- The main role of inner rear mirror is to prevent an accident from happening by giving the driver a line of sight to the rear of the vehicle. In this study, we design and develop an automatic inner rear-view mirror endurance system with an integration of Human Machine Interface (HMI) and the actuator. The objective is to test the endurance of the pivot point of the inner rear-view motor by equipping it with force sensor to measure the force applied in moving the inner rear-view mirror to its limit angle. HMI is used as interaction between user and the actuator because the system requires limit angle and the number of repeated cycles from the user. This paper covers the initial works of the development process. It discusses the design of the system’s actuator, design of the HMI and component selection. A few experiments are conducted to establish communication between PC and the microcontroller. There are still more things need to be done to make the inner rear-view mirror endurance test system a realit

Synthesis of some novel α-cyanoketene-n, s-acetals derived from secondary aliphatic amines and their use in pyrazole synthesis

New α-cyanoketene-N,S-acetals 2(a–g) and β-dialkylamine-α-cyanoacrylates 3(g–i) were synthesized in good to excellent yields by the reaction of ethyl 2-cyano-3,3-bis(methylthio)acrylate 1 with secondary aliphatic amines (i.e., N-methylalkyl- and N-ethylalkylamines), and pyrrolidine, in the presence of triethylamine, under reflux in ethanol, for 1–16 h, depending on the amine used. Five N-methylalkyl amines and pyrrolidine yielded exclusively mono-substituted N,S-acetals 2(a–f) in good yields. On the other hand, N-ethylbenzylamine gave a mixture of monosubstituted products including N,S-acetal 2g in 35% yield and the unexpected product ethyl 3-[benzyl(ethyl)amino]-2-cyanoacrylate 3g in 50% yield. N-Ethylcyclohexylamine and N-ethylbutylamine did not produce N,S-acetals and gave only the unexpected products ethyl 2-cyano-3-[cyclohexyl(ethyl)amino]acrylate 3h and ethyl 3-[butyl(ethyl)amino]-2-cyanoacrylate 3i in good yields. The α-cyanoketene-N,S-acetals 2(a–f), 2j, and 2k underwent cyclization with the binucleophile hydrazine in ethanol under reflux to afford substituted pyrazoles 4(a–f), 4j, and 4k in good yields

Improving plant growth and yield of jatropha (Jatropha curcas L.) through apical bud pinching

A field experiment was conducted to study the effect of the time of apical pinching and genotype on plant growth, flowering time, and yield of Jatropha curcas L. at the Universiti Kebangsaan Malaysia during 2008–2009. Three pinching treatments were used: no pinching or control (P0), pinching during transplanting (P1), and pinching at 30 days after transplanting (P2). Highly significant effect of time of pinching and genotype on plant growth and seed yield was observed. The plant height was significantly reduced by pinching the plant at 30 days after transplanting (72.4 cm) compared to pinching during transplanting (80.0 cm) and no pinching (95.5 cm). The maximum number of primary branches per plant (3.1) with more leaves per plant (113.2) and less plant height (72.2 cm) at first flowering was recorded with pinching at 30 days after transplanting. Among the treatments, unpinched plants produced flowers earlier than the pinched one. The highest number of fruits and seeds per plant along with higher seed yield was recorded in plants pinching at 30 days after transplanting. The maximum number of flowering branches was produced by genotype JC-14 followed by JC-18. The genotypes JC-13, JC-14, JC-17, JC-18, and JC-20 were found to be suitable in respect of reduced plant height; larger number of primary branches per plant; early flowering; and number of fruits, seeds, and seed yield per plant upon pinching

Numerical and experimental investigations on efficient design and performance of hydrokinetic Banki cross flow turbine for rural areas

Micro hydrokinetic energy scheme presents an attractive, environmentally-friendly and efficient electric generation in rural, remote and hilly areas. However, this scheme is yet to be fully discovered, as researchers are still searching for solutions for the main problems of low velocity of current in the open flow channels and low efficiency of hydrokinetic turbines. This research proposes a novel system configuration to capture as much kinetic energy as possible from stream water current. This system, known as bidirectional diffuser augmented (BDA) channel, functions by utilizing dual directed nozzles in the flow and is surrounded by dual cross flow/Banki turbines. It is also important to obtain the efficient design parameters of the turbines to use in the current configuration. The appropriate angle is important in order to guide the flow to touch the blades more perpendicularly to capture as much torque and power as possible. Hence, experimental and numerical investigations have been carried out in this research paper to study the performance characteristics of the CFT configuration applied in BDA system and investigate the effects of blades’ inlet and outlet angles of CFT runners on the internal flow characteristics and efficiency. In this study, four different runners with various inlet and outlet angles of two CFT have been investigated. The CFD results have been validated with the experimental work and proven acceptable with flow pattern and performance characteristics. The results of the current study conclude that the maximum power coefficients (Cp) of 0.612 and 0.473 for lower and upper turbines are recorded for best runner angles of Case 3