Novel Design of HID Lamp Electronic Ballast for Automotive Systems

This paper presents a high intensity discharge（HID） lamp for automotive illumination. A novel type of ballast for HID is proposed without an acoustic resonance. The system consists of high frequency DC/DC converter,DC/AC inverter（SLA2403M）, high voltage igniter and a microcontroller unit（MCU）. The proposed ballast controls the complex start-up process and constant power process by programming on the rnicrocontroller. It is verified that experimental results agree well with the calculated ones. The ballast features such functions as failure protection, line under-voltage, line over-voltage, output short circuit and disconnection protections.

HPS Electronic Ballast Based on CIC-CPPFC Technique

Investigates the application of CIC CPPFC techniques to high pressure sodium(HPS) lamp electronic ballast. In order to ensure a unity power factor, different power electronic ballasts are studied by PSpice simulation. A dynamic model of HPS lamp with simple and accurate features is proposed for further study of characteristics. Experimental results verify the feasibility of HPS lamp operating at high frequency. It is shown that the presented electronic ballast has 0.99 power factor and 9% total harmonic distortion(THD).

Starting of HPS lamps driven by electronic ballast

A complete research of two different starting techniques for HPS lamps driven by electronic ballast is presented while a traditional starting technique based on the series resonant theory which is used widely for fluorescent lamps starting is analyzed in detail. An improved nth harmonic resonant technique is also simulated. Furthermore, a novel starting technique based on a pulse transformer is proposed, which still offer the automatic switch off capability. The differences between two starting techniques are explained. The experimental results from a lab prototype are used to verify the design.

A New-Style Two-Staged Dimmable Electronic Ballast

A two-staged electronic ballast with wide dimming range, high power factor(PF) and low electromagnetic interference(EMI) is presented. It changes the input voltage of the stage of power inverter for dimming control, so it overcomes some limitations of traditional electronic ballasts that use frequency variation. At the same time, the stage of power inverter runs under the soft-switching at the fixed switching frequency and reduces EMI greatly. Its principle and characteristic are analyzed in detail,and experimental and simulated results are obtained on a 40 W fluorescent lamp.

Novel Automotive High Intensity Discharge(HID) Lamps with Electronic Ballasts

A new scheme of automotive high intensity discharge(HID) lamps with electronic ballasts is proposed. The design of the proposed ballast and some experimental results are presented. The proposed scheme is consisted of the high frequency DC-DC converter and the low frequency DC-AC inverter. This system separates the input voltage of the ignitor from DC link voltage using auxiliary winding, then it could use the lower voltage rating power devices for HID lamp ballast system and reduce the size of HID lamp ballast. The proposed ballast controller using micro-controller unit(MCU) controls the frequency to operate the DC-DC converter in critical conduction mode, which reduces the noise of the circuit and improves the efficiency by 2%~4%.

A Novel Single-Switch Single-Stage Electronic Ballast

A single-stage single-switch high- frequency electronic ballast topology is presented. The circuit topology is the integration of a buck power- factor-correction （PFC） converter and a class E resonant inverter with only one active power switch. The buck converter is operated in discontinuous conduction mode and at a fixed switching frequency, and constant duty cycle to achieve high power factor and it can be controlled easily. Detailed analysis of the operation and characteristics of the circuit is provided. Simulation results satisfy present standard requirements.

Analysis of mesoscopic mechanical dynamic characteristics of ballast bed with under sleeper pads

The meso-dynamical behaviour of a high-speed rail ballast bed with under sleeper pads(USPs)was studied.The geometrically irregular refined discrete element model of the ballast particles was constructed using 3D scanning techniques,and the 3D dynamic model of the rail-sleeper-ballast bed was constructed using the coupled discrete element method-multiflexible-body dynamics(DEM-MFBD)approach.We analyse the meso-mechanical dynamics of the ballast bed with USPs under dynamic load on a train and verify the correctness of the model in laboratory tests.It is shown that the deformation of the USPs increases the contact area between the sleeper and the ballast particles,and subsequently the number of contacts between them.As the depth of the granular ballast bed increases,the contact area becomes larger,and the contact force between the ballast particles gradually decreases.Under the action of the elastic USPs,the contact forces between ballast particles are reduced and the overall vibration level of the ballast bed can be reduced.The settlement of the granular ballast bed occurs mainly at the shallow position of the sleeper bottom,and the installation of the elastic USPs can be effective in reducing the stress on the ballast particles and the settlement of the ballast bed.

Experimental and numerical settlement analysis of railway track over geogrid reinforced ballast

Purpose-The main objective of the present research is to investigate the benefits of using geogrid reinforcement in minimizing the rate of deterioration of ballasted rail track geometry resting on soft clay and to explore the effect of load amplitude,load frequency,presence of geogrid layer in ballast layer and ballast layer thickness on the behavior of track system.These variables are studied both experimentally and numerically.This paper examines the effect of geogrid reinforced ballast laying on a layer of clayey soil as a subgrade layer,where a half full scale railway tests are conducted as well as a theoretical analysis is performed.Design/methodologylapproach-The experimental tests work consists of laboratory model tests to investigate the reduction in the compressibility and stress distribution induced in soft clay under a ballast railway reinforced by geogrid reinforcement subjected to dynamic load.Experimental model based on an approximate half scale for general rail track engineering practice is adopted in this study which is used in Iraqi railways.The investigated parameters are load amplitude,load frequency and presence of geogrid reinforcement layer.A half fuli-scale railway was constructed for carrying out the tests,which consists of two rails 800 mm in iength with three w00den sleepers(900 mm×90 mm×90 mm).The ballast was overlying 500 mm thick clay layer.The tests were carried out with and without geogrid reinforcement,the tests were carried out in a well tied steel box of 1.5 m length X 1 m width X 1 m height.A series of laboratory tests were conducted to investigate the response of the ballast and the clay layers where the ballast was reinforced by a geogrid.Settlement in ballast and clay,was measured in reinforced and unreinforced ballast cases.In addition to the laboratory tests,the application of numerical analysis was made by using the finite element program PLAXIS 3D 2013.Findings-It was concluded that the settlement increased with increasing the simulated train load amplitude,there is a sharp increase in settlement up to the cycle 500 and after that,there is a gradual increase to level out between,2,500 and 4,500 cycles depending on the load frequency.There is a little increase in the induced settlement when the load amplitude increased from 0.5 to i ton,but it is higher when the load amplitude increased to 2 ton,the increase in settlement depends on the geogrid existence and the other studied parameters.Both experimental and numerical results showed the same behavior.The effect of load frequency on the settlement ratio is almost constant after 500 cycles.In general,for reinforced cases,the effect of load frequency on the settlement ratio is very small ranging between 0.5 and 2%compared with the unreinforcedcase.Originalitylvalue-Increasing the ballast layer thickness from 20 cm to 30 cm leads to decrease the settlement by about 50%.This ascertains the efficiency of ballast in spreading the waves induced by the track.

Mechanism of cross-level settlements and void accumulation of wide and conventional sleepers in railway ballast

The cross-level and twist irregularities are the most dangerous irregularity types that could cause wheel unloading with the risk of derailments and additional maintenance expenses.However,the mechanism of the irregularities initiation and development is unclear.The motivation of the present study was the previous experimental studies on the application of wide sleepers in the ballasted track.The long-term track geometry measurements with wide sleepers show an enormous reduction of the vertical longitudinal irregularities compared to the conventional track.However,wide sleepers had higher twist and cross-section level irregularities.The present paper aims to explain the phenomenon by discrete element method(DEM)modeling the development process of sleeper inhomogeneous support at cross-level depending on the sleeper form.The DEM simulations show that the maximal settlement intensity is up to 3.5 times lower for a wide sleeper in comparison with the conventional one.Nevertheless,the cross-level differential settlements are almost the same for both sleepers.The particle loading distribution after all loading cycles is concentrated on the smaller area,up to the half sleeper length,with fully unloaded zones under sleeper ends.Ballast flow limitation under the central part of the sleeper could improve the resilience of wide sleepers to the development of cross-level irregularities.The mechanism of initiation of the cross-level irregularity is proposed,which assumes the loss of sleeper support under sleeper ends.The further growth of inhomogeneous settlements along the sleeper is assumed as a result of the interaction of two processes:ballast flow due to dynamic impact during void closing and on the other side high pressure due to the concentration of the pressure under the middle part of the sleeper.The DEM simulation results support the assumption of the mechanism and agree with the experimental studies.

Modelling and Sizing of a Floor Reinforced by Ballasted Columns Intended to Support a Tank

This work aims to study the modeling and sizing of a floor reinforced by ballasted columns. We are studying the system of reinforcement by ballasted columns because this technique is able to replace deep foundations that are technically difficult to realize and their cost is higher. The modelling and dimensioning of foundations on a ballasted column will be an important contribution to the state of the art of this method because it will highlight the mode of transfer of loads, and will expose the induced deformations by also allowing to verification criteria of bearing capacity and allowable settlement according to geometric information of the model. The columns on a substrate located at 9 m have a length of 9 m and a diameter of 40 cm and were obtained by incorporating ballast of granular class 0/31.5 of internal friction angle of 38˚ and a density weight of 21 kN/m3. The choice of this method is based on the geotechnical characteristics of the initial soil. Thus, identification and characterization tests were carried out to estimate the bearing capacity and the settlement giving respectively 125 kPa and 57 cm. These results show the ground does not have sufficient mechanical properties to withstand the loads transmitted by the tank. By adopting the reinforcement of the soil with ballasted columns, numerical calculations show that after applying a load equal to 265.1 KPa, 20 cm vertical settlement and 17 cm horizontal displacement were obtained. This is in the tolerable deformation range for our tank, namely, less than 20 cm. Analytically, in addition to reducing settlement, ballasted columns, Due to their high stiffness, they have effectively contributed to the increase of the permissible soil stress up to 257 kPa.

Stress distribution from railway track over geogrid reinforced ballast underlain by clay

Railway ballast forms a major component of a conventional rail track and is used to distribute the load to the subgrade, providing a smooth running surface for trains. It plays a significant role in providing support for the rail track base and distributing the load to the weaker layer underneath. Ballast also helps with drainage, which is an important factor for any type of transportation structure, including railroads. Over time, ballast progressively deforms and degrades under dynamic loading and loses its strength. In this study, extensive laboratory tests were conducted to investigate the effect of load amplitude, geogrid position, and number of geogrid layers, thickness of ballast layer and clay stiffness on the behavior of the reinforced ballast layer and induced strains in a geogrid. A half full-scale railway was constructed for carrying out the tests, which consisted of two rails 800 mm in length with three wooden sleepers(900 mm × 10 mm × 10 mm). Three ballast thicknesses of 200, 300 and 400 mm were used in the tests. The ballast was overlying 500 mm thickness clay in two states, soft and stiff. The tests were carried out with and without geogrid reinforcement; the tests were performed in a well-tied steel box of 1.5 m length ×1 m width ×1 m height. Laboratory tests were conducted to investigate the response of the ballast and the clay layers where the ballast was reinforced by a geogrid. Settlement in ballast and clay, soil pressure and pore water pressure induced in the clay were measured in reinforced and unreinforced ballast cases. It was concluded that the amount of settlement increased as the simulated train load amplitude increased, and there was a sharp increase in settlement up to cycle 500. After that, there was a gradual increase that leveled out between, 2500 to 4500 cycles depending on the frequency used. There was a slight increase in the induced settlement when the load amplitude increased from 0.5 to 1 ton but it was higher when the load amplitude increased to 2 tons. The increased amount in settlement depended on the existence of the geogrid and other parameters studied. The transmitted average vertical stress for ballast thicknesses of 30 cm and 40 cm increased as the load amplitude increased, regardless of the ballast reinforcement for both soft and stiff clay. The position of the geogrid had no significant effect on the transmitted stresses. The value of the soil pressure and pore water pressure on ballast thicknesses of 20 cm was higher than for 30 cm and 40 cm thicknesses. This meant that the ballast attenuated the induced waves. The soil pressure and pore water pressure for reinforced and unreinforced ballast was higher in stiff clay than in soft clay.

Beam-track interaction of high-speed railway bridge with ballast track

Based on the construction bridge of Xiamen-Shenzhen high-speed railway(9-32 m simply-supported beam + 6×32 m continuous beam),the pier-beam-track finite element model,where the continuous beam of the ballast track and simply-supported beam are combined with each other,was established.The laws of the track stress,the pier longitudinal stress and the beam-track relative displacement were analyzed.The results show that reducing the longitudinal resistance can effectively reduce the track stress and the pier stress of the continuous beam,and increase the beam-track relative displacement.Increasing the rigid pier stiffness of continuous beam can reduce the track braking stress,increase the pier longitudinal stress and reduce the beam-track relative displacement,Increasing the rigid pier stiffness of simply-supported beam can reduce the track braking stress,the rigid pier longitudinal stress and the beam-track relative displacement.

Discrete element method of improved performance of railway ballast bed using elastic sleeper

With the development of high-speed and heavy-haul railway in China, problems like insufficient thickness of ballast bed and overlarge track stiffness are obvious. Ballast may break into small particles and their contact status will deteriorate under cyclic loading, resulting in ballast degradation. Discrete element method(DEM) was used to research improved performance of ballast bed using elastic sleeper. Clusters were generated by bonding spheres to model real ballasts, while broken bonds were utilized to distinguish breakage. Two kinds of ballast beds with elastic sleeper and conventional sleeper were established, respectively. After applying cyclic loading to the models, differences of mechanical properties between two models were analyzed by contrasting their dynamic behavior indexes, such as particle contact force, sleeper settlement, vibration velocity and acceleration, breakage characteristic. The results illustrate that compared with conventional sleeper, elastic sleeper increases sleeper settlement, while reduces ballast vibration and contact force between particles, which could depress ballast breakage.

Design and research on a variable ballast system for deep-sea manned submersibles

Variable ballast systems are necessary for manned submersibles to adjust their buoyancy.In this paper,the design of a variable ballast system for a manned submersible is described.The variable ballast system uses a super high pressure hydraulic seawater system.A super high pressure seawater pump and a deep-sea brushless DC motor are used to pump seawater into or from the variable ballast tank,increasing or decreasing the weight of the manned submersible.A magnetostrictive linear displacement transducer can detect the seawater level in the variable ballast tank.Some seawater valves are used to control pumping direction and control on-off states.The design and testing procedure for the valves is described.Finally,the future development of variable ballast systems and seawater hydraulic systems is projected.

Mechanical behavior and deformation mechanism of ballast bed with various fouling materials

In order to study the interaction between various fouling particles and ballast,a multi-layer and multi-scale discrete element model(DEM)including the sleeper,ballast bed and the surface layer of subgrade was developed.Two typical fouling particles,the hard particles(sand)and soft ones(coal fines),are considered.A support stiffness test of the ballast bed under various fouling conditions was conducted to calibrate the microscopic parameters of the contact model.With the model,the influence of fouling particles on the mechanical behavior and deformation of the ballast bed was analyzed from macro and micro perspectives.The results show that the increase in the strength of the fouling particles enlarges the stiffness of the ballast bed.Hard particles increase the uniformity coefficient of the contact force bondγof ballast by 50.4%.Fouling particles increase the average stress in the subgrade,soft particles by 2 kPa and hard particles by 1 kPa.Hard particles can reduce the elasticity,plastic deformation and energy dissipation in the track structure.As the fouling particle changes from hard to soft,the proportion of the settlement in ballast bed increases to 40.5%and surface layer of swbgrade settlement decreases to 59.5%.Thus,the influence of fouling particles should be considered carefully in railway design and maintenance.

Study on the particle breakage of ballast based on a GPU accelerated discrete element method

Breakage of particles will have greatly influence on mechanical behavior of granular material(GM)under external loads,such as ballast,rockfill and sand.The discrete element method(DEM)is one of the most popular methods for simulating GM as each particle is represented on its own.To study breakage mechanism of particle breakage,a cohesive contact mode is developed based on the GPU accelerated DEM code-Blaze-DEM.A database of the 3D geometry model of rock blocks is established based on the 3D scanning method.And an agglomerate describing the rock block with a series of non-overlapping spherical particles is used to build the DEM numerical model of a railway ballast sample,which is used to the DEM oedometric test to study the particles’breakage characteristics of the sample under external load.Furthermore,to obtain the meso-mechanical parameters used in DEM,a black-analysis method is used based on the laboratory tests of the rock sample.Based on the DEM numerical tests,the particle breakage process and mechanisms of the railway ballast are studied.All results show that the developed code can better used for large scale simulation of the particle breakage analysis of granular material.

Discrete element method analysis of lateral resistance of fouled ballast bed

The lateral resistance of sleeper plays an important role in ensuring the stability of a railway track, which may change in the operation of railway, due to the fouling in the ballast bed. In this work, discrete element method was adopted to investigate the effect of fouling on the lateral resistance of sleeper. The shape information of ballast was captured by method of three-dimensional vision reconstruction. In order to calibrate the mechanical parameters and verify the models, a lateral resistance field test was carried out by using a custom-made device. The contact force distributions in the different parts of sleeper as well as the interaction between ballast and sleeper were discussed in depth. The results show that fouling of ballast bed evidently reduces the lateral resistance of sleeper and the decreasing degree is also related to the fouled position of ballast bed, in the order of shoulder > bottom > side.Therefore, the effect of fouling, especially the fouling in the ballast shoulder, on the lateral resistance of sleeper, should be taken into account in ballast track maintenance work.

Optimization of Bow Shape for a Non Ballast Water Ship

In this research,a commercial CFD code ＂Fluent＂ was applied to optimization of bulbous bow shape for a non ballast water ships（NBS）.The ship was developed at the Laboratory of the authors in Osaka Prefecture University,Japan.At first,accuracy of the CFD code was validated by comparing the CFD results with experimental results at towing tank of Osaka Prefecture University.In the optimizing process,the resistances acting on ships in calm water and in regular head waves were defined as the object function.Following features of bulbous bow shapes were considered as design parameters： volume of bulbous bow,height of its volume center,angle of bow bottom,and length of bulbous bow.When referring to the computed results given by the CFD like resistance,pressure and wave pattern made by ships in calm water and in waves,an optimal bow shape for ships was discovered by comparing the results in the series of bow shapes.In the computation on waves,the ship is in fully captured condition because shorter waves,λ/Lpp 0.6,are assumed.

Added Resistance Acting on Hull of a Non Ballast Water Ship

In this paper, added resistances acting on a hull of non ballast water ship(NBS) in high waves is discussed. The non ballast water ships were developed at the laboratory of the authors at Osaka Prefecture University, Japan. In the present paper, the performances of three kinds of bow shapes developed for the NBS were theoretically and experimentally investigated to find the best one in high waves. In previous papers, an optimum bow shape for the NBS was developed in calm water and in moderated waves. For a 2 m model for experiments and computations, the wave height is 0.02 m. This means that the wave height is 15% of the draft of the ship in full load conditions. In this paper, added resistances in high waves up to 0.07 m for a 2 m model or 53% of the full load draft are investigated. In such high waves linear wave theories which have been used in the design stage of a ship for a long time may not work well anymore, and experiments are the only effective tool to predict the added resistance in high waves. With the computations for waves, the ship is in a fully captured condition because shorter waves, λ/Lpp<0.6, are assumed.

Influence of tire-derived aggregates mixed with ballast on groundborne vibrations

In this paper,the use of recycled tire-derived aggregates(TDA)mixed with ballast material is evaluated in order to reduce the train-induced ground-borne vibrations.For this purpose,a series of field vibration measurements has been carried out at an executed pilot track.The prepared ballast layer was mixed with different percentages of TDA in three sections.Moreover,another test section with pure ballast is considered as a reference.The vibrations generated by a motor-powered draisine at two different speeds are then recorded.Records of vibration data are provided using four seismometers placed once longitudinally and once transversely beside different sections.The outputs are then processed in both velocity–time and velocity–frequency domains.To verify the vibration mitigation performance of TDA in real operation conditions,field measurements under the passage of two planned passenger and freight trains are finally arranged.Results show that the best TDA mixture ratio,i.e.,10%by weight,can reduce the transmitted vibrations up to 12 dB for frequencies above 31.5 Hz.According to the obtained effi-ciency and the very low cost of the recycled materials,this solution can be considered as a competitive vibration countermeasure.