Launch Technology Research Articles

Characterization of Short Intense Pulsed Electrothermal Plasma Capillaries for Use as Fusion and Launchers Heat Flux Sources

Electrothermal plasma sources operating in the confined capillary arc regime are characterized by the magnitude and shape of the discharge current. The desired plasma parameters at the source exit, especially the pressure and heat flux, are highly dependent on the arc due to the effect of the arc radiant energy that ablates the inner wall of the source. These sources have applications in fusion as drivers for pellet injectors and as high heat flux sources for fusion materials studies. The high-pressure high heat flux flow is also of application in mass accelerators and launch technology systems. The 1-D, time-dependent ETFLOW capillary code models the plasma generation and flow inside the capillary discharges and determines the plasma parameters. The input file to the code is the discharge current density providing the Joule heating in the energy equation. A circuit module has been developed and incorporated in the code to generate desired current shapes and magnitudes. The current pulse length was varied between 5 and 100 μs at constant amplitude of 50 kA, and then the pulse amplitude was varied between 10 and 200 kA at a constant pulse length of 20 μs. Increasing the pulse length while maintaining its amplitude increases the plasma density and the total ablated mass, which have accumulation behavior by increasing the pulse length, and subsequently increases the exit pressure from 60 to 410 MPa in the cases studied herein. The pressure increase allows the thermalization of the plasma particles through more collisions, which reduces the plasma temperature by about 0.2 eV. The bulk velocity follows the trend of the plasma temperature, but at shorter pulse lengths the total ablated mass is lower and enables the plasma to carry the particles with increasing velocity. Increasing the pulse amplitude up to 200 kA increases the density to about 18 kg/m3 and the bulk velocity, which varies between 6.1 and 10.7 km/s. A sharp increase in most plasma parameters occurs as a result of the increase in the pulse amplitude.

Deep Drawing of Cylindrical Cup Using Incremental Electromagnetic Assisted Stamping with Radial Magnetic Pressure

A new forming method named incremental electromagnetic assisted stamping with radial magnetic pressure is proposed to draw a deep cylindrical cup. The method combines with traditional stamping, electromagnetic sheet forming and electromagnetic launch technology. Three types of discharge coils are imbedded in die and blank holder, respectively. The 3D finite element model is set up to predict the complex deformation process. The forming process and principle of the new method are discussed. The values of material flow, stress and thickness in different forming processes are compared. In comparison with traditional stamping, incremental electromagnetic assisted stamping with radial magnetic pressure can significantly increase the value of material at sheet end flow inward, decrease the tensile stress and thickness reduction at the easily broken position, and obtain uniform stress distribution. Therefore, deeper cylindrical cup could be manufactured by incremental electromagnetic assisted stamping with radial magnetic pressure.

Guest Editorial The Past, Present, and Future of Electromagnetic Launch Technology and the IEEE International EML Symposia

This Special Issue of the Transactions in Plasma Science consists of selected papers from the Sixteenth International Symposium on Electromagnetic Launch (EML) Technology, held at the China National Convention Center in Beijing, China, May 15-19, 2012. This biennial symposium is the primary forum for presentation and discussion of research on critical technologies for the acceleration of macroscopic objects using EM or electrothermal-chemical launchers. This symposium was cohosted by the Institute for Strategic and Innovative Technologies (ISIT) and the China Electrotechnical Society (CES) under the sponsorship of IEEE's Nuclear and Plasma Sciences Society, was attended by 151 researchers and engineers from 13 countries. The cochairs of the symposium were Dr. Harry Fair (ISIT) and Dr. Jun Li (Beijing Institute of Special Electromechanical Technology). In addition to naming the recipients of the Peter Mark Medal and the First Harry Fair Award, the author reviews the development of EML science and technology during the 1970s and 1980s focusing on the EML Technology Symposium, the first of which was held in San Diego, CA, in 1980. The proceedings were peer reviewed and published as a Special Issue of the IEEE Transactions on Magnetics. The EML Symposia have been held biennially ever since, and all of the EML Symposia have been published as special issues either of the Transactions on Magnetics or more recently in the Transactions of Plasma Sciences. These 16 IEEE issues form the fundamental science and technology base for EML technology.

The Development of EML Technology in China

To make launch weapons with further range, higher energy density, better target accuracy, and better control ability are the aims pursued by people for many years. This paper divides the history of launch technology into four stages, which are the biologic, mechanical, chemical, and electromagnetic launch stages. The development trend of the launch technology is discussed, particularly the advantages of the electromagnetic launch (EML) technology. Recently, China has paid great attention to many new technical fields, such as the EML technology. China's programs are mainly confined to fields of basic research, which are collected together in this paper. However, the numbers of papers published from the 12th symposium to the 16th symposium suggest that there are more and more programs in the EML field.

Simulation of Electromagnetic Force Between Pulsed Inductor and Internal Structure of Power Supply Module

With the development of electromagnetic launch (EML) technology, the pulsed power supply (PPS) module applied in EML needs to be smaller, lighter, and more compact. Electromagnetic force (EMF) is one of the most serious problems when PPS module works with high current. In this paper, we study the PPS module used in EML technology. The pulsed inductor model is built based on structure characteristics. The distribution of current density in the inductor during discharge is analyzed. The finite element analysis software is used to simulate and analyze the characteristics of the induction current and the EMF. The simulation model is composed of inductor and metals structures. The EMF laws are put forward by simulation of different shaped metals at different positions. By analyzing the distribution of the eddy current and EMF on the metal conductors at different positions, the EMF laws between the inductor and metal conductors in PPS module are presented in this paper.

High-Voltage High-Frequency Charging Power Supply Based on Voltage Feedback and Phase-Shift Control

With the rapid development of the electromagnetic launch technology, the performance requirements for the charging power supply are increasing. To control the charging rate accurately and get the steady load voltage, a phase-shift control system was designed. This system adopted the control method which regulates the phase angles of the driving pulses by calculating the relationship of the voltage feedback and the preset charging time. According to the topology and application requirements of a high-voltage high-frequency charging power supply (HVHFCPS), a simulation platform based on the physical security information management software was set up. A prototype of HVHFCPS based on voltage feedback and phase-shift control was developed. The experimental results show that the load voltage can be controlled accurately.

Study on the Characteristics of Different Plasma Ignition Schemes

Plasma ignition mechanisms have always been the central issue in the electrothermal-chemical (ETC) launch technology. Generally, there are two types of ignition schemes, namely, the axial discharge scheme and the radial discharge scheme, and the two schemes are supposed to have different ignition characteristics. This work is devoted to study the features of different plasma ignition schemes in the ETC launch devices. A capillary discharge setup and a gap discharge setup are utilized in the experiments to represent the axial and radial discharge ignition schemes, respectively, and three types of propellants are used in the study. Using the measured data in the experiments, plasma heat fluxes are solved by a plasma-propellant interaction model. In addition, the propellant surface conditions are investigated by a scanning electron microscope after the plasma ignition experiments. The surface conditions of propellants in different ignition schemes display distinct features, which are analyzed to shed light on the characteristics of different ignition schemes and the responses of different propellants. Results are supposed to help in interpreting the plasma-propellant interaction mechanisms in different ignition schemes and provide references for the optimization design of plasma ignition installations in the ETC launch devices.

Effects of the Launch Speed on Hydrodynamic Force of the Underwater Vehicle Vertical Launch with the Gas Curtain

The vertical launch of the gas curtain is a new underwater launch technology. The gravity effect of the launch speed on hydrodynamic characteristics of the underwater vehicle vertical launching by using the gas curtain has been studied by adopting the multiphase VOF model and the standardturbulence model. The relationship between the launch speed and the shape of the underwater vehicle has been achieved by using the numerical simulation. The relationships between the launch speed and the hydrodynamic characteristics of the underwater vehicle vertically launching from the tube, navigating in water and exiting water have been investigated by using numerical simulation. The hydrodynamic characteristics of underwater vehicle vertical launching by using the gas curtain method are small. The effects of the launch speed on the hydrodynamic characteristics of the underwater vehicle vertical launching in the gas curtain are small.

Interaction features of different propellants under plasma impingement

The development of electrothermal chemical launch technology and the effective ignition of energetic thermoplastic elastomer (ETPE) propellants all call for a thorough understanding of the plasma propellant interaction mechanism. Therefore in this work, a numerical model is developed to study this process. In this model, special attention is paid to deal with the regression of propellant surface, which is caused by plasma ablation, and is assumed to have considerable influence on the interaction process. By this model, interaction features of four propellants, including two ETPE propellants are studied with the aid of experiments, which are carried out to obtain plasma parameters utilized in the model. Surface temperature, ablation rate, and surface regression rate are obtained for different propellants under plasma impingement. Finally, the influence of propellant composition and charging voltage are analyzed.

Cherub: Fine-grained application protection with on-demand virtualization

Cherub is an on-demand virtualization mechanism aiming to provide fine-grained application protection in untrusted environments. By leveraging late launch technology, Cherub dynamically inserts a lightweight virtual machine monitor (VMM) under a commodity operating system (OS) when critical pieces of an application code or data are to be processed. The novel design of Cherub with a double-shadowed page table extends VMM level memory protection into application level, such that it can isolate selected memory pages of a target process from the rest and other processes in the same OS environment. With this, Cherub enables fine-grained memory access control and therefore flexible security objectives. Compared to existing approaches, Cherub has the benefits of small code size, low performance overhead, no change to existing applications and commodity OS, and selective protection capability within a single application space. We implement Cherub in Linux and our analysis and evaluation demonstrate its effectiveness and practicality.

Numerical Simulation of Launch Tube Based on Container–type Missile Launch Technology

According to the features of container–type missile launch technology for multi-barrel rocket, combined with non-lethal weapons in the field of application, a new concept about the launching unit for anti-riot rockets, which was the integration of storing and launching non-lethal rockets, was proposed. The load bearing on the launcher was analyzed and engineering plastics were selected as launch tube materials. Combined the computer aided design software Pro/Engineer with the finite analysis software ANSYS, the numerical simulation of the launch tube was created. To ensure the launch tube design according with the theoretical design requirements, the stress and displacement of the launch tube under the maximum load were analyzed in comparison. The results reflected that the stiffness and intensity of launch tube can fully meet the needs for launching.

Design and Testing of a 10-MJ Electromagnetic Launch Facility

For basic research on electromagnetic launch technology, the Beijing Institute of Special Electromechanical Technology has initiated a program focusing on the design and testing of a 10-MJ electromagnetic launcher facility with the cooperation of Nanjing University and the Institute of Electrical Engineering, Chinese Academy of Sciences. The facility will consist of a 10-MJ prime energy, a 6-m-long railgun, and a control system. A 3.2-MJ pulse power unit (PPU) with 32 100-kJ modular PFN units has been completed and tested, and its prime energy can be easily extended to 10 MJ. A 6-m-long railgun has been built, which can be easily cut into a 4-m-long railgun by which many firings have been done with the new PPU. Construction and testing of the whole facility are being continued.

Some Aspects Concerning the Design of Multistage Earth Orbit Launchers Using Electromagnetic Acceleration

This paper reports on reflections undertaken to establish a possible multistage space-launch system based on the use of combined electromagnetic and rocket launch technology. It is assumed that the direct access to space is not possible using a single-stage system only, since for such a system, muzzle velocities of approximately 10 km/s are required. Multistage chemical rockets have been successfully used for Low Earth Orbit missions. They are now a mature technology; continued system efficiency improvements are expected to yield only marginal progress. Alternative technology paths, such as the Lorentz rail accelerator (LRA), hold the potential for considerable improvements in first-stage efficiencies compared to rocket systems. Such unconventional solution has serious consequences for the accelerator and payload carrier design. In the first part of this paper, some general aspects (size, forces, energy, and power) of an electromagnetic launcher, which could be able to achieve the required muzzle momentum for such a mission, are discussed. More specifically, the design of such a launcher with respect to the type of electromagnetic LRAs (known also as railguns) and to the armature technology is considered, and also, some of the interstage aspects of such a system are investigated. Special attention is paid to solutions increasing the launch efficiency of the electromagnetic launcher. The second part of this paper considers possible design properties of the rocket carrier (booster and kickoff stage). Propulsion system, structure under high acceleration, thermal protection system (TPS), carrier aerodynamics, and flight mechanic properties are analyzed. The performed analysis confirms that the rocket carrier can be realized with the present technology within the next decade. The conclusion is valid under the assumption that a start velocity from a ground-based electromagnetic LRA is limited to about 4.5 km/s if an adequate TPS is applied. At higher velocities, the extreme heat loads destroy the payload carrier.

Special Issue on Selected Papers From the EML Symposium

The 95 papers in this special issue were originally presented at the 15th International Symposium on Electromagnetic Launch (EML) Technology, held at the Royal Military Academy (RMA) in Brussels, Belgium, May 17-20, 2010.

Simulations on Elastoplasticity of the Monolithic Aluminum Armature Under the Contact Force

Keeping good contact of the armature-rail interface (ARI) is essential for electromagnetic launch technology. To investigate the contact mechanism of ARI and improve the contact condition, the elastic-plastic deformation of the monolithic aluminum armature (MAA) under the contact force is analyzed. Contact force, contact area, and the distribution of contact pressure are calculated, and several kinds of armatures with different arm lengths are compared under the same conditions. The calculating loads include the pretightening force under the initial preload and the electromagnetic force from the pulse current. The simulation results show that both the contact force and the contact area under the plastic deformation are bigger than those under the elastic deformation, which is due to the higher spring-back force and displacement. A longer arm length can result in better flexibility and lower contact force. The effect of the electromagnetic force versus the contact force is increased with the arm length.

Runtime Software Trustworthiness Evidence Collection Mechanism Based on TPM

PDF HTML阅读 XML下载 导出引用 引用提醒 基于TPM的运行时软件可信证据收集机制 DOI: 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: Supported by the National Basic Research Program of China under Grant No.2009CB320703 (国家重点基础研究发展计划(973)); the National High-Tech Research and Development Plan of China under Grant Nos.2007AA01Z462, 2007AA010304, 2008AA01Z133 (国家高技术研究发展计划(863)); the Fund for Creative Research Groups of China under Grant No.60821003 (国家创新研究群体科学 基金) Runtime Software Trustworthiness Evidence Collection Mechanism Based on TPM Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:扩展了已有的软件可信性证据模型,引入了运行时软件可信证据,从而提供了更为全面的软件可信证据模型.为了提供客观、真实、全面的可信证据,提出了一种基于可信计算技术的软件运行时可信证据收集机制.利用可信平台模块(trusted platform module,简称TPM)提供的安全功能,结合“最新加载技术(late launch)”,在操作系统层引入了一个可信证据收集代理.此代理利用TPM,可以客观地收集目标应用程序的运行时可作为软件可信证据的信息,并保障可信证据本身的可信性.该可信证据收集机制具有良好的可扩展性,能够支持面向不同应用的信任评估模型.基于Linux Security Module,在Linux中实现了一个可信证据收集代理的原型.基于该原型,分析了一个分布式计算客户端实例的相关可信属性,并且分析了可信证据收集代理在该应用实例中的性能开销.该应用实例验证了该方案的可行性. Abstract:This paper extends the software trustworthiness evidence framework to include the runtime software trustworthiness evidence. To collect software trustworthiness evidence in an objective, genuine and comprehensive way, it proposes a runtime software trustworthiness evidence collection mechanism based on trusted computing technology. Based on the features provided by TPM (trusted platform module), as well as the late launch technology, a trusted evidence collection agent is introduced in an operating system kernel. The agent can securely monitor executing programs and collect their trustworthiness evidence accordingly. The agent also provides some trusted services for programs to collect application specific evidences and guarantees the trustworthiness of these evidences. This mechanism has good scalability to support various applications and software trustworthiness evaluation models. This paper also implements a prototype for the agent based on Linux security model in Linux. Based on the prototype, it studies the trustworthiness evaluation for executing a client program in a distributed computing environment. In this application, the performance of prototype is studied, and the feasibility of this approach is demonstrated. 参考文献 相似文献 引证文献

IMC strategies in new high technology product launches

PurposeThe purpose of this paper is to provide empirical evidence on the use of IMC in new high technology product launches among companies that operate in different fields of business, yet providing similar innovation to the same market.Design/methodology/approachA qualitative case research methodology is applied. Multiple sources of evidence are gathered. These include interviews with key informants and documentary data, and IMC mini audits. Concerning the theoretical approach, the related literature in IMC, new product launch and high technology marketing is reviewed.FindingsIMC is vital to high technology marketers launching new products and services. The analyses reveal that IMC practices vary across firm size, industry type, product/service orientation, and customer orientation.Practical implicationsCompanies of different types can be on an equal footing in their integration efforts. Whether service‐ or product‐oriented companies, business‐to‐consumer or business‐to‐business marketers, companies from all backgrounds can achieve higher levels of IMC. What matters most is customer‐centricity, i.e. having a close interaction with customers and being responsive to their feedback.Originality/valueThe study contributes to the integrated marketing communications research field in several important respects. First, it focuses on IMC usage among firms in different industries. Second, it takes a genuinely refreshing view on studying IMC strategies by focusing on usage of IMC as part of new high technology product launch strategy.

Advances in Electromagnetic Launch Science and Technology and Its Applications

The U.S. continues a broad spectrum of research to provide the scientific underpinnings for electromagnetic launch. These efforts include fundamental research on materials, properties of materials subjected to electromagnetic and thermal stresses, railguns (particularly the rail-armature sliding interface), coilguns, and energy storage and power conditioning. There is also broad and growing interest in novel applications of electromagnetic launch. For example, a supersonic beam of neon atoms have been slowed and stopped, opening the door for investigating the atomic and molecular properties of most of the periodic table of atoms and certain molecules. Research is continuing on magnetic brakes and the more traditional research on the launch of materials to hypervelocities. More recently, the launching of materials into the Earth's orbit or even deeper in space is obtaining renewed interest. Consequently, some attention is being given to the types of materials of projectiles for hypersonic flight. The U.S. Navy has initiated new multidisciplinary university research teams including physics, chemistry, and materials science to develop new diagnostic tools and to provide a more detailed examination of the rail-armature interface. Most significantly, the U.S. Army has elevated its emphasis from electromagnetic launch science and technology development to the operational consequences of long-range precision fires. In concert with the recent U.S. Navy efforts on long-range fires, it is anticipated that the pull of these applications will enable even greater advances in the science and technology of electromagnetic launch.

Research for the Control System of a Pulsed Power Permanent Linear Synchronous Motor

Pulsed power linear motor is the basic power device in electromagnetic launching (EML) technology. When this technology combines with permanent magnetic linear synchronous motor (PMLSM), a pulsed power permanent magnet linear synchronous motor (PP-PMLSM) is generated. In this paper, the analysis of cogging force and thrust characteristic of this type of motor are presented, and the scheme comparison of bilateral magnet arranged by N face S with N face N direction is made, at last, the digital control system of the PP-PMLSM is designed and realized. The system design is simple, and it improves the control effect.

Introduction

The 88 papers in this special issue were originally presented at the 14th International Symposium on Electromagnetic Launch (EML) Technology, held in Victoria, British Columbia, Canada, June 10-13, 2008.