Potential Health and Safety Hazards of Marine Lubricants

1. Introduction Marine lubricants are generally formulated from highly refined mineral oils and special additive systems; a limited number of products Within the range utilize synthetic base oil (Morrison and Boyd, 1969). To ensure health and safty when using any petroleum product it is essential that: ●it is used only for the purposes for which it is intended, ●it is safety and hygiere conditions are observed. Health and safety aspects which is intended to assist the management of shipping companies to ensure that all personnel coming into direct contact With lubricants are familiar with the potential hazards associated With them,

Low-Temperature Synthesis of Nano-AlN Based on Solid Nitrogen Source by Plasma-Assisted Ball Milling

Plasma-assisted ball milling was carried out on the Al+C3H6N6 system and Al+C_(4)H_(4)N_(4) system,respectively.The phase structure,functional groups and synthesis mechanism were analyzed by XRD and FT-IR,and the differences in the synthesis process of nano-AlN with different solid nitrogen sources were discussed.The results show that C3H6N6 has a stable triazine ring structure,and its chemical bond is firm and difficult to break,so AlN cannot be synthesized directly by solid-solid reaction at room temperature.However,there are a large number of nitrile groups(-CN)and amino groups(-NH_(2))in C_(4)H_(4)N_(4) molecules.Under the combined action of plasma bombardment and mechanical energy activation,C_(4)H_(4)N_(4) molecules undergo polycondensation and deamination,so that the ball milling tank is filled with a large number of active nitrogen-containing groups such as N=,≡N,etc.These groups and ball milling activated Al can synthesize nano-AlN at room temperature,with a conversion rate of 92%.SEM,DSC/TG analysis showed that the powder obtained by ball milling was formed by soft agglomeration of many fine primary particles about 50–80 nm.The surface morphology of the powder was loose and porous,and it had strong activity.After annealing at 800℃,the conversion rate of the Al+C_(4)H_(4)N_(4) system reached 99%.

Numerical study of the splashing wave induced by a seaplane using mesh-based and particle-based methods

In recent years,forest fires and maritime accidents have occurred frequently,which have had a bad impact on human production and life.Thus,the development of seaplanes is an increasingly urgent demand.It is important to study the taxiing process of seaplanes for the development of seaplanes,which is a strong nonlinear fluid-structure interaction problem.In this paper,the smoothed particle hydrodynamics(SPH)method based on the Lagrangian framework is utilized to simulate the taxiing process of seaplanes,and the SPH results are compared with those of the finite volume method(FVM)based on the Eulerian method.The results show that the SPH method can not only give the same accuracy as the FVM but also have a strong ability to capture the splashing waves in the taxiing process,which is quite meaningful for the subsequent study of the effect of a splash on other parts of the seaplane.

Measurement of thermal conductivity,viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids

This article studied experimentally the effect of multi-wall carbon nanotubes(MWCNTs)on the thermo physical properties of ionic liquid-based nanofluids.The nanofluids were composed of ionic liquid,1-ethyl-3-methylimidazolium diethylphosphate [EMIM][DEP],or its aqueous solution[EMIM][DEP](1)+ H_2O(2)and MWCNTs without any surfactants.The thermal conductivity,viscosity and density of the nanofluids were measured experimentally.The effects of the mass fraction of MWCNTs,temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied.Results show that the thermal conductivity of nanofluids increases within the range of 1.3%–9.7% compared to their base liquids,and have a well linear dependence on temperature.The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids.Finally,the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.

Transition of Streamer, Corona and Glow Discharges in Needle-to-plane Dielectric Barrier Discharge at Atmospheric Pressure Air

To discuss the modes of dielectric barrier discharge(DBD) between needle-to-plane electrodes in air,DBD is generated and observed on a needle-to-plane device at atmospheric pressure air.Fast images of the DBD are taken by using a charge couple device(CCD) cinema with a macro lens,while the electrical and photo-electricity waveforms of the DBD are recorded.The current waveforms show that under an applied voltage of 3 kV,there are numerous short current pulses in both positive and negative half-periods of discharges.However,under 6 kV,there are still the numerous short current pulses in the positive half-periods,but only one wide current pulse in each negative half-period.This difference is also found in the photoelectric signals.The streamer,corona and glow discharges are observed from the images of the discharges at different applied voltages.The structure of glow discharge in the negative period is exactly the same as that of the low pressure glow discharge.However,in the positive period of discharge there is always a streamer.In the negative period of discharge,while the applied voltage increases,the transition from corona to glow discharge is observed.The progress of a transition between streamer and glow discharge at 6 kV during one period is analyzed.The glow discharge appearance is determined by two factors: the discharge current is limited to a certain extent by the dielectric layer; the charges deposited on the dielectric layer during the last half period enhance the intensity of the electric field.At an insufficient applied voltage,the cathode drop leads to no glow discharge,but Trichel pulses.

Characteristics of DBD micro-discharge at different pressure and its effect on the performance of oxygen plasma reactor

The oxygen plasma reactor based on dielectric barrier discharge principle can produce a high concentration of reactive oxygen species,which can cooperate with hydraulic cavitation gas-liquid mixer to realize the application of advanced oxidation technology in water treatment.In this technology,the work pressure of the oxygen plasma reactor is decreased by the vacuum suction effect generated in the snap-back section of the gas-liquid mixed container.In this paper,the characteristics of single micro-discharge at different pressures were investigated with the methods of discharge image,electrical characteristics and spectral diagnosis,in order to analyze the electrical characteristics and reactive oxygen species generation efficiency of oxygen plasma reactor at the pressure range from 60 kPa to 100 kPa.The study indicated that,when the pressure decreases,the duty ratio of ionization in the discharge gap and number of electrons with high energy increases,leading to a rise in reactive oxygen species production.When the oxygen reaches the maximum ionization,the concentration of reactive oxygen species is the highest.Then,the discharge intensity continues to increase,producing more heat,which will decompose the ozone and lower the production of reactive oxygen species.The oxygen plasma reactor has an optimum working pressure at different input powers,which makes the oxygen plasma reactor the most efficient in generating reactive oxygen species.

Use of Diesel Engine and Surface-Piercing Propeller to Achieve Fuel Savings for Inshore Fishing Boats

钓鱼是在马来西亚的主要本地工业，特别地在农村区域。然而，燃料的很快增加的价格严重正在影响工业生存能力。目前，因为他们交付高速度和低重量的优点，舷外的汽油引擎是为在小规模的钓鱼的船的使用的比较喜欢的选择，他们是安逸的安装，并且他们使用最小的空间。汽油舷外的引擎被知道消费燃料的更大的数量比向内柴油机引擎，而是有在存在的常规沉没推进器的安装柴油机引擎小规模的钓鱼船因为主要 hullform 修正和额外的开销被要求完成这，不是经济地可行的。这研究描述一个建议由介绍一台柴油机引擎和穿透表面的推进器(SPP ) 的联合使用在燃料消费启用减小。燃料消费减小的分析被介绍，和经济可行性研究。产生数据表明建议修正的使用将与舷外的马达相比每旅行(40.75 %) 节省燃料的 23.31 公升，每年等于 RM 3962 的年度积蓄。

Adsorption equilibrium and the effect of honeycomb heat exchanging device on charge/discharge characteristic of methane on MIL-101(Cr)and activated carbon

Experiments were conducted for developing suitable ANG adsorbents for vehicular applications.MIL-101 and activated carbon samples were respectively prepared by hydrothermal and chemical activation methods.Two samples were undergone structure analysis on adsorption data of nitrogen at 77.15 K,and adsorption data of methane were then volumetrically measured within temperature-pressure range 293.15 K-313.15 K and 0-8 MPa.A conformable vessel in volume 2.5 L was employed for charge/discharge tests under the flow rate 10-30 L·min^-1.It shows that limit isostreic heat of methane adsorption is respectively about 25.15 k J·mol^-1 and22.94 k J·mol^-1 on the activated carbon and the MIL-101,and isosteric heat within the experimental condition is 14-19.5 k J·mol^-1;employing a smaller charge/discharge flow rate can weaken the temperature fluctuation of the adsorbent bed and increase the charge/discharge amount;employing honeycomb heat exchanging device enhance the thermal conductivity of the adsorbent bed by consuming a negligible part of volume of the vessel.It suggests that a smaller flow rate for charge/discharge should be employed,and MOFs together with the honeycomb heat exchanging device are promising for practical applications.

Treatment of Microalgae in Ballast Water Using Hydroxyl Radical in Accordance with the D-2 Ballast Water Discharge Standard

The effect of hydroxyl radical(·OH) on microalgae in ballast water is experimentally investigated. An ?OH plasma generator, which has a thin plate discharge Ag electrode covered by two α-Al2 O3 dielectric layers, is built. The plasma generator is filled with O2 and gaseous H2 O and is powered by a homemade power supply. ?OH radicals are generated by a series of plasma reactions and then dissolved into ballast water to kill microalgae. The maximum density of the killed microalgae is about 11 000 cells per milliliter. At this density, the microalgae are not reactivated at the 48th hour and the 120th hour in the treated ballast waters, and the content of chlorophyll in these microalgae decreases by 100%. The water quality returns to a normal level after 120 hours without secondary pollution of aquatic organisms and environment. These results show that the requirements of the D-2 ballast water discharge standard defined by the International Maritime Organization(IMO) are satisfied with the proposed treatment, and that ·OH is an ideal substance for killing microalgae during ballast water replacement of ships.

Research on resonance parameters matching based on partitioned operation method of atmospheric pressure plasma reactor array

Matching optimization of resonant parameters among the high power inverters,low power transformers and plasma reactors have significant effects on the performance and output of the reactor array when applying the partitioned operation method.In this paper,the Matlab/Simulink electrical model was established based on the method of partitioned operation.The matching relation between resonant parameters is analyzed on the basis of experimental result.As a consequence,transformer leakage inductance and working frequency are the important parameters influencing the operational efficiency of system,leakage inductance of transformer should be adjusted based on the equivalent capacitance of plasma reactor to realize the matching optimization of resonant parameters.

A useful guide of effective mesh-size decision in predicting the ultimate strength of flat-and curved plates in compression

The present study aims to determine the appropriate size of mesh or the number of the element(NoE)for flat-and curved plates,which is suggested to assess its safety subjected to axial compression based on the ultimate limit state(ULS)design and analysis concept.The unstiffened panel(=plate)and stiff-ened panel,considered primary members of ships and ship-shaped offshore structures,are subjected to repeated axial compression and tension caused by continued vertical bending moments applied to the hull girder.Plates are attached with stiffeners by welding,and 6,8 or 10 elements are generally rec-ommended to allocate in flat-plate’s breadth direction in between stiffeners for finite-element(FE)mod-elling,which enables the presentation of the shape of initial deflection applied to the plate.In the case of the load-shorting curve for curved plate,it is reported that the nonlinear behaviour characteristics,i.e.,snap-through,snap-back,secondary buckling and others,appear in typical flank angle.To take this into account,we investigated the preferred number of elements(6,8 or 10)generally applied to the flat plate whether it is an appropriate or more fine-sized element(or mesh)that should be considered.A useful guide is documented based on obtained outcomes which may help structural engineers select optimised mesh-size to predict ultimate strength and understand its characteristic of the flat and curved plates.

Experimental Realization of an Extreme-Parameter Omnidirectional Cloak

An ideal transformation-based omnidirectional cloak always relies on metamaterials with extreme parameters,which were previously thought to be too difcult to realize.For such a reason,in previous experimental proposals of invisibility cloaks,the extreme parameters requirements are usually abandoned,leading to inherent scattering.Here,we report on the frst experimental demonstration of an omnidirectional cloak that satisfes the extreme parameters requirement,which can hide objects in a homogenous background.Instead of using resonant metamaterials that usually involve unavoidable absorptive loss,the extreme parameters are achieved using a nonresonant metamaterial comprising arrays of subwavelength metallic channels manufactured with 3D metal printing technology.A high level transmission of electromagnetic wave propagating through the present omnidirectional cloak,as well as signifcant reduction of scattering feld,is demonstrated both numerically and experimentally.Our work may also inspire experimental realizations of the other full-parameter omnidirectional optical devices such as concentrator,rotators,and optical illusion apparatuses.

光滑粒子流体动力学框架下的EoSB空化模型及空化流动数值模拟研究

过去十余年来,光滑粒子流体动力学(Smoothed Particle Hydrodynamics,SPH)研究领域一直在探索空化流动的数值模拟,但迄今为止依然没有精确且稳定的SPH空化模型.本文将阐述一种在SPH框架内实现空化流动模拟的数值方法.首先,为了捕捉空化初生及其发展,本文在SPH框架内提出一种基于状态方程的相变模型.特别地,本文还引入一种粒子体积自适应算法(Volume Adaptive Scheme,VAS),以保证空化区域流体剧烈膨胀时粒子体积分布的均一性.此外,本文还采用粒子位移修正技术(Particle Shifting Technique,PST)和张力不稳定性控制技术(Tensile Instability Control,TIC)以提高粒子分布质量和抑制数值空洞的产生.最后,本文还通过引入大涡模拟(Large Eddy Simulation,LES)模型以考虑湍流效应,提高本文提出的SPH空化模型对高雷诺数流动的适用性.研究结果表明,本文提出的基于SPH方法的新空化模型能实现空化区域和压力分布等问题的精确预报.