Mechanical properties and thermal conductivity of pristine andfunctionalized carbon nanotube reinforced metallic glass composites:A molecular dynamics approach

This work uses the molecular dynamics approach to study the effects of functionalization of carbon nanotubes (CNTs) on the mechanical properties of Cu64Zr36 metallic glass (MG). Three types of functional groups, carboxylic, vinyl and ester were used. The effect of CNT volume fraction (Vf) and the number of functional groups attached to CNT, on the mechanical properties and thermal conductivity of CNT-MG composites was analysed using Biovia Materials Studio. At lower values of Vf (from 0 to 5％), the per-centage increase in Young's modulus was approximately 66％. As the value of Vf was increased further (from 5 to 12％), the rate of increase in Young's modulus was reduced to 16％. The thermal conductivity was found to increase from 1.52 W/mK at Vf=0％to 5.88 W/mK at Vf=12％, thus giving an increase of approximately 286％. Functionalization of SWCNT reduced the thermal conductivity of the SWCNT-MG composites.     

Using stochastic programming to solve an outpatient appointment scheduling problem with random service and arrival times

We study a stochastic outpatient appointment scheduling problem (SOASP) in which we need to design a schedule and an adaptive rescheduling (i.e., resequencing or declining) policy for a set of patients. Each patient has a known type and associated probability distributions of random service duration and random arrival time. Finding a provably optimal solution to this problem requires solving a multistage stochastic mixed‐integer program (MSMIP) with a schedule optimization problem solved at each stage, determining the optimal rescheduling policy over the various random service durations and arrival times. In recognition that this MSMIP is intractable, we first consider a two‐stage model (TSM) that relaxes the nonanticipativity constraints of MSMIP and so yields a lower bound. Second, we derive a set of valid inequalities to strengthen and improve the solvability of the TSM formulation. Third, we obtain an upper bound for the MSMIP by solving the TSM under the feasible (and easily implementable) appointment order (AO) policy, which requires that patients are served in the order of their scheduled appointments, independent of their actual arrival times. Fourth, we propose a Monte Carlo approach to evaluate the relative gap between the MSMIP upper and lower bounds. Finally, in a series of numerical experiments, we show that these two bounds are very close in a wide range of SOASP instances, demonstrating the near‐optimality of the AO policy. We also identify parameter settings that result in a large gap in between these two bounds. Accordingly, we propose an alternative policy based on neighbor‐swapping. We demonstrate that this alternative policy leads to a much tighter upper bound and significantly shrinks the gap.     

Book reviews

John Lawrence Tone, The Fatal Knot: The Guerrilla War in Navarre and the Defeat of Napoleon in Spain. Chapel Hill and London; The University of North Carolina Press 1994. Pp.vii + 239, 1 map, biblio., index. $34.95 (cloth). ISBN 0–8078–2169–1.

Robert Holland (ed), Emergencies and Disorder in the European Empires after 1945. London: Frank Cass, 1994. Pp.x + 256; index. £32 (cloth); £15 (paper). ISBN 0–7146–4516–8 and 4109 X

Deborah L. Norden, Military Rebellion in Argentina: Between Coups and Consolidation. Lincoln, NE: University of Nebraska Press, 1996. Pp.242, index, $35/$17.50 (paper). ISBN 0–8032–8369–5.

William M. Minter, Apartheid's Contras: An Inquiry into the Roots of War in Angola and Mozambique. London and Atlantic Highlands, NJ: Zed Books Ltd; Johannesburg: Witwatersrand University Press, 1994. Pp. xii +308, 3 maps, biblio., index. $69.95/£39.95 (cloth); $29.95/£16.95(paper). ISBN 1–85649–266–4 and 266–4.     

Baixa do Cassang: Ending the abuse of Portuguese Africans

On 4 January 1961 in Baixa do Cassange, in the north of Angola, the blacks who worked in the cotton fields began a strike. The army with air support was called to quell the rebellion, and the article emphasizes the importance of air support tethered to the ground forces, particularly in a remote and vast area of operations in the tropical rainy season. In this case, the support originally came in the form a squadron of Lockheed PV-2 Harpoons from Luanda, some 300 kilometers away. These open-ocean reconnaissance aircraft and their crews were ill-suited for the task. When this became apparent, four small Auster D5/160s were relocated from Negage to Malange, among the ground forces. The Austers flew reconnaissance missions over the troubled zones, dropped provisions and messages to the advancing ground forces, and served as a backup communications link. When the strike ceased after three weeks, the Austers assumed a humanitarian role in support of the starving population. The conclusion is that air support to ground forces is indispensable, must be properly tailored to the job, and must operate as an integral part of the ground forces.     

The military recruiting productivity slowdown: The roles of resources,opportunity cost and the tastes of youth*

After a decade of successful recruiting, the US military began experiencing recruiting difficulties in the 1990s. Cyclical factors as well as trend factors may have played a role. This paper uses monthly data by state over the period 1989-1997 to estimate models of enlistment and evaluate the various explanations for the recruiting slowdown. Estimates of the impact of economic variables - relative military pay and unemployment - and recruiting resource variables - recruiters and advertising - are similar to those in previous studies. Two trend factors, rising college attendance and declining adult veteran population (influencers), are found to be important factors explaining the decline in enlistment.     

WHO IS THE ENEMY?

We examine who benefits when there is a strong leader in place, and who benefits when a situation lacks a proper leader. There are fractious terrorist groups who seek to serve the same people in common cause against a common enemy. The groups compete for rents obtained from the public by engaging in actions against the common enemy. We determine the leadership structure under which each group is better off, as well as the circumstance that the common enemy prefers. We are able to state simple and general conditions for each group and the common enemy to benefit.     

The right place at the right time,or the right person in the right place?

South Africa's military has, since the First World War, been an oft-used and effective tool in the conduct of South African foreign policy, but this role has not always translated into power for Defence Department principals in its formulation. South African Defence Ministers for most of the country's history have played a minor role in the making of foreign policy; despite a change in this dynamic between approximately 1975–1990, the post-apartheid era has once again seen a diminishment of Defence's power in this arena. This article examines why Defence Ministers have generally been such weak players, with an eye toward disaggregating whether this was a product of interpersonal relationships with Cabinet and – most importantly – the Head of State, or whether this influence (or lack thereof) was more a function of South Africa's international standing. While determining who has influence on this process is difficult given the primacy of the national leader in making foreign policy and a lack of insider accounts by participants in the process, this article relies upon several interviews with participants and knowledgeable observers that help illuminate the process and Defence's role in it.     

Defence closure and job loss: The case of swan hunter on tyneside

Recently in this journal Hooper and Butler (1996) drew attention to the scale of job loss associated with restructuring in the defence sector in the aftermath of the Cold War. They noted that there is comparatively little knowledge of the experiences of workers following the closure of defence plants. This research communication attempts to shed further light on this issue by reporting the results of a survey of the experiences of former Swan Hunter shipyard workers who were made redundant after the firm went into receivership. The results confirm the complex but generally negative effect of redundancy on the workers involved.     

The inherent propensity toward peace or war embodied in weaponry

Thomas Schelling argues that armed adversaries face an inherent propensity toward peace or war embodied in their weaponry, geography and military organizations. Inherent propensity is the idea that there are characteristics embodied in the weapons that push adversaries toward peace or war, independent of the goals of the decision‐makers, the political disagreement between adversaries, and misperceptions about mutual resolve and hostility. We theoretically illustrate inherent propensity in conventional and nuclear arms settings using Lanchester and Intriligator war models. Our work extends the Intriligator‐Brito model, identifies when the competing Richardson and Intriligator‐Brito views of the relationship between arms races and war are correct, illustrates the stabilizing/destabilizing effects of alliances, and highlights the importance of arms quality control in the US‐USSR relationship.