粉末燃料冲压发动机内镁粉尘云层流燃烧模型

对粉末燃料冲压发动机预燃室内镁粉尘云燃烧过程进行了研究,建立了镁粉尘云的一维层流预混燃烧模型。研究表明,镁粉尘云层流火焰传播很稳定,燃烧过程中火焰结构基本不变,燃烧区很薄,而预热区厚度约是燃烧区的2-3倍。粉尘云中镁颗粒的蒸发和气相镁与氧气的均相反应是产生火焰的直接原因,也是火焰得以传播的关键。预热区气相温度升高主要靠燃烧区气体的导热和扩散过来的气相镁与氧气反应释放热量,而预热区颗粒相温度升高主要靠气相对其对流传热。分析了各参数对粉尘云燃烧的影响,颗粒相对浓度对粉尘云燃烧的影响比较复杂,在浓度较低的情况下,增大颗粒相对浓度有利于粉尘云快速燃烧;而在浓度较高的情况下,增大颗粒相对浓度则不利于粉尘云快速燃烧。随颗粒粒径的增加,火焰传播速度减小,火焰温度升高,预热区厚度增大。火焰传播速度和火焰温度随粉尘云初温增加线性增长,预热区厚度随粉尘云初温增加抛物线增长。数值模拟与文献中试验结果的变化趋势相一致。     

AID,GLENEAGLES AND THE RUN-UP TO THE MILLENNIUM +5 SUMMIT

Africa has emerged as a strategic location for transcontinental narcotics trade. Particularly the West African subcontinent has turned into a cocaine warehousing and trans-shipment hub along the way to the European underground markets. At this juncture, African drug networks (ADNs) began to play a momentous role in global drug trade, and pose a considerable threat to international security, as they operate in more than 80 countries. The United Nations Office on Drugs and Crime, Interpol, and Europol perceive ADNs as one of the primary issues in international counter-narcotics policy. These agencies have launched several multilateral initiatives to contain the West African threat. None of these initiatives, however, retarded the expansion of the problem. Indeed, the containment efforts turned out to be quite embryonic. The ADNs eventually entered the Turkish market by the early 2000s. West African drug networks (WADNs) in particular have begun to operate within Turkey extensively, often supplying and distributing drugs. The gravity of the threat became ever more serious by 2012. The upsurge of the new threat has compelled the Turkish drug-law enforcement agencies to adopt new policies and counter-strategies. These policies have to be based upon proper strategic analysis of the threat. This paper seeks to address the need for a threat assessment of ADNs. It investigates the dimensions of the problem, profiles the members of WADNs, their modes of operation, and the factors that compelled them to exploit the illicit Turkish drug markets. The analyses are based upon the scrutiny of 227 narcotic interdictions files and statements from the African individuals in these case files. The paper concludes by presenting policy implications and recommendations for the Turkish security and foreign-policy institutions to cope with this impending threat.     

FOUNDATIONS FOR REGIONAL SECURITY: PREPARING TO KEEP THE PEACE IN SOUTHERN AFRICA

Since the terrorist attacks of 11 September 2001, the continent of Africa, particularly Greater East Africa, has played an increasingly signifi cant role in United States (US) national security strategy. Transnational security threats and political authoritarianism continue to plague the region, creating calls for greater US and international involvement. Before reacting to the situation, however, it is prudent to pause, reflect, and understand that the United States developed strategic relations with nation-states in the region well before contemporary concerns for international terrorism and ungoverned spaces entered the strategic lexicon. Toward a more comprehensive understanding of Greater East Africa's strategic history, this paper examines the core strategic relationship in the region, US-Kenya relations, its origins and implications, and offers policy recommendations that will affect future international security.     

NUCLEAR ISLANDS

Current International Atomic Energy Agency safeguards do not provide adequate protection against the diversion to military use of materials or technology from certain types of sensitive nuclear fuel cycle facilities. In view of highly enriched uranium's relatively greater ease of use as a nuclear explosive material than plutonium and the significant diseconomies of commercial spent fuel reprocessing, this article focuses on the need for improved international controls over uranium enrichment facilities as the proximate justification for creation of an International Nuclear Fuel Cycle Association (INFCA). In principle, the proposal is equally applicable to alleviating the proliferation concerns provoked by nuclear fuel reprocessing plants and other sensitive nuclear fuel cycle facilities. The INFCA would provide significantly increased nonproliferation assurance to its member states and the wider international community by holding long-term leasehold contracts to operate secure restricted zones containing such sensitive nuclear facilities.     

THE EUROPEAN UNION'S EVOLVING ENGAGEMENT WITH IRAN

In 2003, the “E3”—Germany, France, and the United Kingdom—engaged Iran in talks over Tehran's nuclear program and were joined in negotiations the next year by the European Union (EU). Given the dim prospects of success for these talks, why did the E3/EU pursue nuclear negotiations with Iran? This article's three-track analysis attempts to answer that question by examining the emergence of the EU nonproliferation policy prior to the E3/EU-Iran talks, analyzing the European-Iranian relationship as it pertains to cooperation and negotiations over nonproliferation and other issues, and considering contemporary influences on the E3/EU. The European Union was ultimately unsuccessful in its negotiations with Tehran, but its efforts were worthwhile. In the future, the organization can play a vital nonproliferation role; today, the circumstances that hampered previous European efforts to resolve the Iranian nuclear standoff have improved and could be capitalized on by the European Union and the international community.     

HEU FUEL CYCLE INVENTORIES AND PROGRESS ON GLOBAL MINIMIZATION

In 2007, 334 nuclear reactors (including for naval propulsion) and isotope production facilities employed highly enriched uranium (HEU) fuel or target material. One year of operations at these reactors and facilities required more than 3,100 kilograms (kg) of HEU for naval propulsion, more than 750 kg for research reactors, and 40?–50 kg for isotope production in civilian facilities—in addition to several tons used in other types of reactors. Material with high enrichment levels and low radiation barriers stored or handled in large batches, such as HEU target waste and certain types of fuel from isotope production, research reactors/critical assemblies, and naval fuel, presents serious safety and security concerns. Forty-eight civilian research reactors have converted to low-enriched uranium as a result of a three-decade international effort to minimize HEU use, resulting in a decrease in HEU consumption of 278 kg per year. This article's establishment of baseline measurements for assessing the results of HEU minimization efforts calls for additional focus on the scope and methodology of HEU minimization. Facility decommissioning and dismantling should play a larger role in the future HEU minimization effort, materials with specific weapons-relevant properties should be given higher priority compared to bulk HEU material, and the use of large quantities of weapon-grade HEU fuel for naval propulsion should be reconsidered.     

In spite of reform: NATO HQ still in the grips of nations

Security Intergovernmental Organizations, here illustrated by NATO, persist in a “permitted interval” of internationalization, i.e. permitted by its member-states. On the one hand, they are seldom or never permitted to vanish due to member-states' vested interests in retaining them as tools of statecraft, even if their original purposes have become redundant. On the other hand, there is an internationalization ceiling that they must respect: they should not become too autonomous and thereby no longer be suitable as member-state tools. In spite of post-Cold War reform, interviews carried out at NATO Headquarters (HQ) in the late 1980s compared to interviews in 2012 display that a continuous pulling and hauling of forces of internationalization and renationalization have taken place around NATO HQ. The only instance of clear internationalization can be observed in the proactive diplomacy of Secretary General Fogh Rasmussen. There is stiff opposition to the internationalization of abolishing the Military Committee/International Military Staff among minor and South European states, and there is no waning in states' attempts to micro-manage the International Staff. Only external shocks can overcome resistance to internationalizing reform.     

Aligning national “logics” in a European military helicopter program

This article analyzes the public side of the NH90 network consisting of four participating countries (Germany, France, Italy, and the Netherlands) and their industrial partners. Comparable to observations in earlier international projects in the defense sector, the development and production of the NH90 defense helicopter did not match original plans and costs estimates. On the basis of four mechanisms that were intended to facilitate the cooperation between the partnering countries (the General Memorandum of Understanding; coalition formation; the role of the central agency; and the process of vertical escalation) the question is posed whether or not there was a true alignment of national interests and “logics.” The lack of standardization, as well as program delays and issues concerning the division of the work-share, lead to the emerging alignment being characterized as “quasi-alignment” at best.     

The legality of unmanned aerial vehicles outside the combat zone: a case study of the Federally Administered Tribal Areas of Pakistan

The drone is the latest tool to promote interests of a nation-state. It is clear that USA as well as other major powers anticipate that robotics will play a key role in future warfare. Today, more than 70 countries have already acquired drone technology and many others are desperate to join the ranks. This urge for drone technology will ultimately lead to a “boundless and borderless war without end.” In the case of Pakistan, the US drone campaign has raised some important issues regarding how their use could, or should, be regulated in the future. This article analyses the legal issues raised by the US's use of drone technology in non-combat zones, such as Pakistan. It is argued that a reckless disrespect of Pakistan's sovereignty has had adverse implications and consequences for the legitimacy of the Pakistani government. Drone strikes have prompted instinctive opposition among the Pakistani population, hurt their feelings and estranged them from the government. This in turn has added to Pakistan's instability and stimulated a ground-swell of animosity toward the USA.     

高海拔下柴油机燃用含氧燃料的试验研究

为解决高海拔地区因缺氧和燃料燃烧不完全造成的发动机动力下降和燃油消耗率增加的问题,将生物柴油以不同体积分数(5%,10%)掺混到柴油中进行发动机台架试验。通过控制发动机进气压力模拟高海拔条件下含氧燃料的燃烧,考察平原和海拔3 000 m地区不同掺混比例的含氧燃料对发动机性能的影响。结果表明:在平原燃用含氧燃料,发动机功率较燃用纯柴油有所降低,且降幅随生物柴油添加量的增加而增大,同时燃油消耗率上升;在海拔3 000 m地区燃用含氧燃料,发动机功率较燃用纯柴油有所增加,且燃油消耗率下降;不管是在平原还是在海拔3 000 m地区,燃用含氧燃料均能够显著降低HC、CO和碳烟排放,但NOx排放有所增加。