The relationship between maritime education and employer trust: the structural equation modelling (SEM) perspective

The research is aimed to identify factors in the maritime education and training (MET) system and its relationship on maritime labour employers’ (MLEs) trust based on current practice in Malaysia. A questionnaire survey was used, and the respondents were the participants of a related conference in Malaysia. The structural equation modelling technique was used to explain the relationships in the stipulated research model. The test of structural model confirms that the model is adequate in explaining the MLEs’ trust. The results reveal that the perceived MET institutions’ efficiency has significant direct effects on the MLEs’ trust and the perceived seafarers’ competency. In addition, the perceived implementation of International Convention was found to significantly affect the seafarers’ competency. However, the perceived seafarers’ competency was not found to directly affect the MLEs’ trust. This study suggests that the MLEs’ trust is an important indicator and feedback on it can be used to further enhance the current MET system and its policies. Thus, one of the strategies is to develop a policy in order to achieve an effective maritime education and training. This is to support the maritime communities in progressing towards a more sustainable development in the MET in the context of enhancing the maritime safety.     

Investigation of the capabilities of yield functions on describing the deformation behavior of 5754O aluminum alloy sheet under combined loading paths

The combined loading tests of 5754O aluminum alloy sheet are used to verify the yield function. Three yield functions are implemented into the commercial finite element model (FEM) code ABAQUS as a user material subroutine UMAT for the FEM simulation of the combined loading tests. The comparison of the simulating and experimental results shows that the modified Yld2000-2d yield function can describe the mechanical behavior of 5754O aluminum alloy sheet under combined loading paths reasonably while other three yield functions do not. The performance of the modified Yld2000-2d yield function on describing the mechanical behavior under combined loading paths is analyzed in detail. It is concluded that the modified Yld2000-2d yield function can be adopted to describe the deformation behavior of 5754O aluminum alloy sheet for industrial applications.     

“I can do perfectly well without a car!”

This article presents the results of a study exploring travellers’ preferences for middle-distance travel using Q-methodology. Respondents rank-ordered 42 opinion statements regarding travel choice and motivations for travel in general and for car and public transport as alternative travel modes. By-person factor analysis revealed four distinct preference segments for middle-distance travel: (1) choice travellers with a preference for public transport, (2) deliberate-choice travellers, (3) choice travellers with car as dominant alternative, and (4) car-dependent travellers. These preference segments differ in terms of the levels of involvement and cognitive effort in travel decision making, the travel consideration-set and underlying motivations. The study showed that for most people there is more to travel than getting from point A to point B, and that there is considerable heterogeneity in middle-distance travel preferences. Policy implications for reducing the need for travel and promoting a modal shift from car to other travel modes are discussed.     

Construction of eukaryotic recombinant vector of renalase and its expression as a eukaryotic protein

Renalase is a secreted amine oxidase that metabolizes catecholamines. It has been proposed to modulate blood pressure and heart rate and its downregulation might result in hypertension. Despite its potential relevance for human health, the biochemical characterization of renalase is still scarce. The aim of this study is to synthesize the human renalase eukaryotic protein by genetic engineering. The human renalase gene was amplified by polymerase chian reaction (PCR). After digestion by BamH I and Xho I enzymes, the DNA fragments were cloned into the transfer vector, pFastBacHTb-Fc, to generate the pFastBacHTb-renalase expression vector. The ligation products were transformed into E. coli DH10Bac to obtain recombinant transposon rBacmid-renalase. The recombinant transposon was further transferred into insect high-V cells, and the recombinant human renalase eukaryotic protein was expressed successfully.     

船用液控蝶阀节流调速系统的数字仿真(英文)

Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters in a throttle governing system with a hydraulic butterfly valve. It also determines the type and specification of the hydraulic butterfly valve and the design of motion parameters of the transported fluid.     

The two-dimensional study of the interaction between liquid loshing and elastic structures

Sloshing phenomenon in the liquid cargo carriers has caught the attention of researchers as the interaction between the sloshing waves and structure is one of the key point and difficulty in the study of sloshing. In this paper, we captured the free surface with a volume of fluid (VOF) method and then calculated the motions and responses of the structure by adopting the Reynolds-averaged Navier-Stokes (RANS) equations for the whole fluid domain. With the use of user defined functions (UDF) in Fluent, the interaction between fluid and structure was then simulated. As a reasonable simplification, the authors studied the response of a single cantilever in a tank under sloshing loads; Further study should pay more attention to the mechanisms of interaction between sloshing waves and elastic structures.     

Research of scalability of the belt-type sensor networks

For the large-scale application requirements of the belt-type networks, the mathematical modeling as well as quantitative analysis for the scalability of the network based on average path length is completed in this paper, and the theorem for the scale scalability of the belt-type networks is derived. The theorem provides a calculation formula for the upper limit of node scale theory of the belt-type networks and a calculation formula for the upper limit of single node load theory.     

Truck capacity analysis in a cross‐dock transportation network considering direct shipment

In a transportation network, decision making parameters may change and may cause the optimum value of objective function to vary in a specific range. Therefore, managers try to identify the effects of these changes by sensitive analysis to find appropriate solutions. In this paper, first, a model for cross‐dock transportation network considering direct shipment is presented, and then an algorithm based on branch and bound algorithm and dual price concept for sensitive analysis is developed. When managers encounter problems such as budget limit, they may decide to change the capacity of trucks as a procedure to reduce the transportation costs of the network. The algorithm provides a useful lower bound on the solutions of the problems and makes it easy for the managers to eliminate inappropriate options of truck capacities, which cannot lead to cost reduction. To verify the algorithm, an example will be given at the end of the paper. Copyright © 2013 John Wiley & Sons, Ltd.     

3D numerical modeling of wave forces on tandem fixed cylinders using the BEM

In this paper a 3D numerical model was developed to study the complicated interaction between waves and a set of tandem fixed cylinders.The fluid was considered to be inviscid and irrotational.Therefore,the Helmholtz equation was used as a governing equation.The boundary element method（BEM） was adopted to discretize the relevant equations.Open boundaries were used in far fields of the study domain.Linear waves were generated and propagated towards tandem fixed cylinders to estimate the forces applied on them.Special attention was paid to consideration of the effect on varying non-dimensional cylinder radius and distance between cylinders,ka and kd on forces and trapped modes.The middle cylinder wave forces and trapped modes in a set of nine tandem cylinders were validated utilizing analytical data.The comparisons confirm the accuracy of the model.The results of the inline wave force estimation on n tandem cylinders show that the critical cylinder in the row is the middle one for odd numbers of cylinders.Furthermore the results show that the critical trapped mode effect occurs for normalized cylinder radiuses close to 0.5 and 1.0.Finally the force estimation for n tandem cylinders confirms that force amplitude of the middle cylinder versus normalized separation distance fluctuates about that of a single cylinder.     

Research of order allocation model based on cloud and hybrid genetic algorithm under ecommerce environment

For massive order allocation problem of the third party logistics (TPL) in ecommerce, this paper proposes a general order allocation model based on cloud architecture and hybrid genetic algorithm (GA), implementing cloud deployable MapReduce (MR) code to parallelize allocation process, using heuristic rule to fix illegal chromosome during encoding process and adopting mixed integer programming (MIP) as fitness function to guarantee rationality of chromosome fitness. The simulation experiment shows that in mass processing of orders, the model performance in a multi-server cluster environment is remarkable superior to that in stand-alone environment. This model can be directly applied to cloud based logistics information platform (LIP) in near future, implementing fast auto-allocation for massive concurrent orders, with great application value.