Long-term probability distribution of fixed offshore structuralresponse using animproved version of finite memory nonlinear system procedure

Offshore structures are exposed to random wave loading in the ocean environment and hence the probability distribution of the extreme values of their response to wave loading is required for their safe and economical design. Due to nonlinearity of the drag component of Morison’s wave loading and also due to intermittency of wave loading on members in the splash zone, the response is often non-Gaussian [1-2]; therefore, simple techniques for derivation of the probability distribution of extreme responses are not available. However, it has recently been shown that the short-term response of an offshore structure exposed to Morison wave loading can be approximated by the response of an equivalent finite-memory nonlinear system (FMNS) [3]. Previous investigation shows that the developed FMNS models reduce the computational effort but the predictions are not very good for low intensity sea states. Therefore, to overcome this deficiency, a modified version of FMNS models is referred to as MFMNS models is used to determine the extreme response values which improves the accuracy but is computationally less efficient than FMNS models. In this paper, the 100-year responses derived from the long-term probability distribution of the extreme responses from MFMNS and FMNS models are compared with corresponding distributions from the CTS method is investigated with the effect of current to establish their level of accuracy. The methodology for derivation of the long-term distribution of extreme responses (and the evaluation of 100-year responses) is discussed. The accuracy of the predictions of the 100- year responses from MFMNS and FMNS models will then be investigated

Comparison of the extreme responses from different methods of simulating wave kinematics

Linear random wave theory (LRWT) is frequently used to simulate water particle kinematics at different nodes of an offshore structure from a reference surface elevation record. However, it is well known that LRWT leads to water particle kinematics with exaggerated high-frequency components in the vicinity of mean water level (MWL). Methods have been introduced to overcome this problem of high kinematics above the MWL consists of using linear wave theory (such as Wheeler, vertical stretching, effective node elevation and effective water depth methods) can be used to provide a more realistic representation of near- surface wave kinematics. There is promising as there is some evidence that the water particle kinematics from the Wheeler method are underestimated and that those from the vertical stretching method are somewhat exaggerated. In this paper, the comparisons of the probability distributions of extreme values from different methods of simulation wave kinematics are investigated by using Monte Carlo simulation procedure

The effect of wave in-deck in conventional pushover analysis

Subsidence is not a local settlement and one of the phenomena that may be experiencing by the offshore platform throughout the platform life. Compaction of the reservoir can cause it due to pressure reduction resulted to vertical movement of soils from the reservoir to mudline. The impact of subsidence on platforms will lead to a gradually reduces wave crest to deck air gap (insufficient air gap) and causing the Wave-in-Deck (WID) on platform deck. The WID load can cause a major consequence damage to the deck structures and potential to the collapse of the entire platform. The aim of this study is to investigate the impact of WID (with and without load) on structure response for fixed offshore structure. The usual run of pushover analysis only considering the base 100-years design crest height for the ultimate collapse. Thus, by calculating the wave height at collapse using a limit state equation for probabilistic model can give a significant result for WID. It is crucial to ensure that the Reserve Strength Ratio (RSR) is not overly estimated hence giving a false impression of the value. This study is performed in order to quantify the WID load effect on producing the new revised RSR. Finally, a parametric study on the probability of failure (POF) of the platform will be performed. As part of the analysis, the USFOS Software (Non-linear) and wave-in-deck calculation as suggested by ISO 19902 as practice in the industry are used in order to complete the study. It is expected that the new revised RSR with the inclusion of WID load will be lower hence increases the POF of the platform. The accuracy and effectiveness of this method will assist the industry, especially operators, for the purpose of decision-making and, ore specifically, for their outlining of action items as part of their business risk management

Cut-off in their prime? Response of two landscape shrubs to different levels of root pruning, during active and quiescent growth phases

Shrubs have an important role in the future design of urban landscapes. Due to city-densification and pressure on space, shrubs are increasingly preferred over trees for urban amenity plantings. In contrast to trees, however, relatively little information exists on how shrubs adapt to urban stress. This includes their responses to physical root injury, that might occur through trenching or transplanting activities. Two shrub taxa, Philadelphus coronarius ‘Aureus’ and Euonymus fortunei ‘Silver Queen’, were used to investigate the effects of severity and time of root injury on plant viability, and how additional fertiliser influenced recovery. A novel ‘split-pot’ system was developed to differentiate where root injury was induced. Results showed that both taxa were relatively resilient to root-pruning, although root injury was more detrimental during active growth than when plants were quiescent. This re-enforces the notion that transplanting of shrubs should be avoided in the summer. Shoot development was not more detrimentally affected by severe root-pruning compared to light pruning. There was also evidence that uniform severe pruning across the root-ball stimulated stronger root-regeneration compared to root systems differentially injured. No consistent response to fertiliser was noted. Results have implications for the resilience and management of shrubs within the urban landscape

FAKIH: A method to teach deaf people ‘reading’ Quran

Allah revealed the Quran to be practiced by all human beings irrespective of whether the humans are normal, or mentally or physically challenged. According to the Department of Malaysian Special Education, in 2002, there were 663 blind students and 3649 deaf students, all over Malaysia. However, in terms of Quran education, deaf students are far behind compared to blind students. This is because they could not hear and therefore posed a difficult situation for the teachers to teach them. Based on this initiative, Fakih methods have been introduced to eight deaf students to learn Quran in within two months. The result is very promising where six of them managed to recite Quran through hand code using Fakih method. We propose iPad application called iFakih in the future to cater the needs of disabled people to read Quran

Investigation of simple portable telescope validity for muon detection inside metals

Muons produced in the atmosphere by cosmic rays are preferred over gamma rays, X-rays and fast protons for the detection of metals in the study of radiography. An alternative method for metals detection involving portable and relatively cheap Geiger-Muller counters are proposed. The objective of this study was to investigate the validity of using a handmade muon telescope with a small solid angle for the detection of muons inside the metals. This experiment was carried out at Universiti Kebangsaan Malaysia, Bangi (101.78º E, 2.92º N and elevation 30 m). Measurement of muons was conducted in the vertical direction using 1 set of muon telescopes (MT) consisting of coaxial Geiger-Muller (GM) counters. Different metals - lead (Pb), zinc (Zn) and aluminium (Al) - were used as absorbers with different thickness to observe its influence on the count rate of muons. The efficiency of the experimental setup was evaluated using statistical methods and by obtaining sufficient number of muon detection events to describe the physics of the muon interaction with the metals. Based on the Rossi curve obtained for each metal, the transition point was estimated as follows: 1.5 cm for Pb, 4.0 cm for Zn, and 9.0 cm for Al. The results showed that the proposed alternative setup was adequate for detecting muons and therefore have the potential to be further developed

MULTI-RESPONSE OPTIMIZATION OF PLASTIC INJECTION MOULDING PROCESS USING GREY RELATIONAL ANALYSIS BASED IN TAGUCHI METHOD

This project investigates the multi-response optimization using grey relational analysis based in Taguchi method of plastic injection mould. Four input process parameters selected are mould temperature, melting temperature, injection time and cooling time. The responses investigated were part weight, shrinkage, warpage, ultimate tensile strength, tensile modulus and percentage of elongation. It is found that the optimum setting parameter generated from multi-response optimization is at run number 4 that are mould temperature at 56oC, melting temperature at 250oC, injection time at 0.7s and cooling time at 15.4s. Result of run number 4 for multi-response optimization for part weight, warpage, shrinkage, tensile ultimate strength, tensile modulus and percentage of elongation are 6.9807g, 0.087mm, 1.73%, 24.732MPa, 981.76MPa and 31.37%, respectively. Multi-response optimization results show that all response results are not higher or lower than experimental results. This is because multi-response optimization normalized all response value. Thus, by implemented multi-response optimization process, the materials characteristics value of plastic part can be predicted