bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigating Difference: Applications of Wealth Ranking and Household Survey Approaches among Farming Households in Southern Zimbabwe
Authors: Scoones Ian
Published: October 2008

Wealth ranking and household survey approaches to understanding wealth stratification are applied in tandem for a sample of farming households in southern Zimbabwe. While conventional surveys usually stratify sample populations according to criteria chosen by the researcher, wealth ranking is based on criteria offered by local people. Patterns of wealth and well‐being over time, between ecological zones and in relation to local indicators are explored with focus groups of men and women. The rankings emerging from these discussions are compared with survey data for the same household sample. The wealth rankings are highly correlated with livestock ownership, farm asset holdings, crop harvests and crop sales. Wealth ranks derived from farmers' analyses are then compared with a cluster analysis of the survey data, with both discrepancies and overlaps discussed. It is concluded that wealth ranking provides an accurate indicator of relative wealth and that ranking can be a useful complementary method to be employed alongside survey assessments. In addition, qualitative discussions during ranking exercises reveal details of the historically, socially and economically constructed understandings of wealth and well‐being of different actors. The conventional assumption that surveys always provide ‘better’ data is thus questioned.
Biodiversity Conservation: The Process of Economic Assessment and Establishment of a Protected Area in Vanuatu
Authors: Tacconi Luca , Bennett Jeff
Published: October 2008

This article describes the framework adopted for the socio‐economic assessment of protected areas intended to safeguard biodiversity. This framework, which can be described as a three‐tiered approach to conservation, is applied to the process of assessment and establishment of a protected area (PA) in Vanuatu. The potential benefits that the landowners of the PA could derive from logging activities, and the subsistence values derived from the PA are considered. It appears that if the PA was to be established without the payment of any compensation, the landowners would face substantial net costs. During the research process, it was suggested that the Government of Vanuatu could take up a lease on the land to compensate the landowners for the loss of potential logging royalties. When the benefits accruing to the landowners from a lease agreement are compared with the foregone logging royalties, it is found that the net present value of a seventy‐five year lease agreement is approximately equivalent to the net present value of logging royalties.
Formalizing the Informal Sector: Barriers and Costs
Authors: Lagos Ricardo A.
Published: October 2008

This article uses material from a series of case studies conducted in Latin America to analyse various aspects of the formalization of the informal sector. In particular, it examines the legal and bureaucratic barriers confronting informal sector micro‐enterprises which seek to become part of the formal, legal circuit, and assesses the costs in time and money which are involved in the formalization process. The process itself is seen as consisting of two elements — achieving legality and retaining that status over time — each of which involves certain bureaucratic and financial demands. While recognizing that the requirements for formalization can represent a burden in some cases, the main finding of the article is that the procedures and related costs vary between countries to such a degree that it is impossible to claim, as some earlier studies have done, that disproportionate regulation and bureaucracy constitute an insurmountable obstacle to the legalization of informal sector enterprises.
Beyond Naivety: Women, Gender Inequality and Participatory Development
Authors: Mayoux Linda
Published: October 2008

In recent years, participatory development has become an established orthodoxy among development agencies across the political spectrum; at the same time, the importance of consulting with and recruiting women has been highlighted in most discussions of participatory strategies. Drawing on the author's own research and a range of secondary sources, this article focuses on gender aspects of participatory projects. The evidence suggests that gender inequalities in resources, time availability and power, influence the activities, priorities and framework of participatory projects just as much as ‘top‐down’ development and market activities. Contrary to the view of a number of writers and activists on participatory development, increasing the numbers of women involved in participatory projects cannot, therefore, be seen as a soft alternative to specific attention to change in gender inequality. Meeting the demands of poor women in the South will require not only local participatory projects, but a linking with wider movements for change in the national and international development agenda.
Structural Adjustment, Democratization and Rising Ethnic Tensions in Africa
Authors: Adekanye J. ‘Bayo
Published: October 2008

Structural adjustment, democratization and rising ethnic tensions characterize the current situation in much of Africa today. This article examines how these tendencies interact causally. It begins by describing Africa's growing debt (combined with defence) burden, the nature of the structural adjustment programme (SAP), particularly its pressures and contradictions, and the increasingly authoritarian responses generated by these. After illustrating the linkage between SAP and rising ethnic tensions, it is suggested that the issue of the distribution of power, wealth and ethnicity, especially under conditions of increasing scarcity, needs to be reconsidered. There are a number of reasons why ethnic and regional tensions are exacerbated by debts, economic crisis and adjustment in Africa; a core argument of this article is that the current ethnic tensions, like the ongoing democratic struggles, are arising as part of the general resistance against both SAP, because of its pauperizing impact, and against the state, which is seen as increasingly coercive and as negligent of its basic welfare responsibilities towards its citizens. The article ends by considering the implications of the coincidence of these two foci of resistance not only for the democratization project, but also for the survival of the state in Africa.
Dismantling the Divide Between Indigenous and Scientific Knowledge
Authors: Agrawal Arun
Published: October 2008

In the past few years scholarly discussions have characterized indigenous knowledge as a significant resource for development. This article interrogates the concept of indigenous knowledge and the strategies its advocates present to promote development. The article suggests that both the concept of indigenous knowledge, and its role in development, are problematic issues as currently conceptualized. To productively engage indigenous knowledge in development, we must go beyond the dichotomy of indigenous vs. scientific, and work towards greater autonomy for ‘indigenous’ peoples.
The Response of International Organizations to the Environmental Challenge: The Case of the United Nations Industrial Development Organization (UNIDO)
Authors: Baark Erik , Strahl Joseph
Published: October 2008

This article examines the effectiveness of UNIDO in addressing the challenges of environmental degradation and in helping developing countries promote sustainable development paths. The analysis suggests that the slow process of integrating environmental concerns in UNIDO's activities was affected both by internal organizational factors, such as the shared professional values in UNIDO's institutional culture and its organizational flexibility and responsiveness, and by factors relating to the external context, including financial constraints and interagency conflicts. In contrast to studies of successful persuasion of ‘epistemic communities’ in international negotiations, this article looks at the factors which have impeded the process of persuasion. At the theoretical level, it seeks to analyse the difficulties of changing the policy agenda in a specific international organization.
Structural Adjustment and Performance in Living Standards in Developing Countries
Authors: Kakwani N.
Published: October 2008

Over the years, the World Bank's structural adjustment programmes have been criticized on the grounds that they have adverse effects on the living standards of the people in developing countries. The main objective of this article is to test the hypothesis that the adjustment lending countries have had a superior (or inferior) performance to the non‐adjustment lending countries during the 1980s. A new dummy variable regression model is used to test this hypothesis. The model controls for initial conditions, external shocks and other exogenous variables which affect different countries differently. The standard of living is measured by several socioeconomic variables including per capita income, lifeexpectancy at birth, infant mortality rate, and literacy rate.
Plantation Labour and Economie Crisis in Cameroon
Authors: Konings Piet
Published: October 2008

The few existing studies on the response of labour to the economic crisis and structural adjustment in African countries tend to focus on the (oppositional) relations between the state and central labour organizations. They largely ignore the response of workers and unions at the workplace. This article describes how workers and unions in the tea estates of Cameroon have dealt with the economic crisis and structural adjustment. It shows that the workers have adopted various strategies to cope with the structural adjustment measures planned and implemented by the management in close co‐operation with the state‐controlled unions. Two striking facts to emerge from the analysis are that the majority of the estate workers have never completely abandoned their ‘traditional’ militancy, and that gender differences in the degree and modes of labour resistance tend to be slight.
Towards Reconciliation of the Land Issue in Namibia: Identifying the Possible, Assessing the Probable
Authors: Pankhurst Donna
Published: October 2008

This paper argues that the case against a major land reform in Namibia is overstated and inaccurate, and that, in spite of its relatively harsh climate, the country contains sufficient land of good enough quality, and a small enough population, to undertake a major land reform. The paper suggests that the reasons why there is generally a conservative estimate of possible solutions to land hunger are largely related to the prevalence of a conservative colonial intellectual legacy in spite of radical ambitions stated by the SWAPO (South West African People's Organization) government. Furthermore, many commentators and officials in Namibia are following a pattern in Africa of ignoring lessons (positive and negative) from other countries—in this case particularly from aspects of Zimbabwe's land reform. The paper explores the comparison with Zimbabwe in order to emphasize the political lessons available for Namibia's land reform, but it also highlights practical lessons which exist, in spite of the fact that most of Zimbabwe's environment is generally much better suited to agriculture than is Namibia's.
The State, The Market and Economic Development: A Second Look at Adam Smith in Theory and Practice
Authors: Goldsmith Arthur A.
Published: October 2008

This article looks at the place of government in the development of market economies. Using ideas from Adam Smith, and illustrations from Anglo‐American economic history, it shows how government was deeply involved in creating the conditions for capitalism and in moulding a sustaining environment for private enterprise. Despite the claims of contemporary laissez‐faire ideology to the contrary, the emergence and the maintenance of a capitalist economic system always depend, at least in part, on an effective state.
The Positive Economics of Inflation in Brazil
Authors: Blumenschein Fernando
Published: October 2008

High and unstable inflation rates have prevailed in Brazil during the period 1985‐92. All attempts to stabilize the economy have failed and ‘living with inflation’ has become politically feasible. The structure of the financial market in general, and financial adaptation mechanisms in particular, have played a crucial role in implementing and maintaining this political‐economic option. Financial adaptation mechanisms sway the management of monetary and fiscal policies, with a direct influence on the credibility of macroeconomic policy announcements. More importantly, distributive asymmetries generated by those financial instruments, in association with differences in political motivation for different groups in the society, have created a stalemate regarding stabilization efforts. This article argues that, for the Brazilian case, the positive economics literature has failed to explain the inflationary phenomenon because it has not considered financial adaptation as an important linkage between political motivation of certain groups in the society and the correspondent desirable economic outcomes. The validation of social‐economic objectives of certain classes became an important raison d'être of financial adaptation. Consequently, change of inflationary regimes carries costs and benefits far beyond those implied by fiscal reform alone.
Islamic Banking in Practice: the Case of Pakistan
Authors: Cornelisse Peter A. , Steffelaar Wouter
Published: October 2008

In Islamic banking rules apply which differ from those in traditional banking. This article first discusses the consequences of Islamic banking for financial operations in general, then goes on to examine the Islamic procedures introduced in Pakistan's banking sector since 1985. Considering the drastic change in procedures, the effect of Islamization on this sector has been moderate. One reason for this is that banks in Pakistan have consistently opted for financial instruments closely resembling interest‐based finance. Another reason is that their behaviour has been determined to a large extent by the fact that they are state‐owned.
Public Intervention and Poverty Alleviation: A Study of the Declining Incidence of Rural Poverty in Kerala, India
Authors: Kannan K.P.
Published: October 2008

In the context of the continuing and lively debate on the estimates, trends and determinants of rural poverty in India, this article examines the sharp decline, since the late 1970s, in the incidence of rural poverty in the state of Kerala, well known for its record of social development. It is argued that, given the slow rate of growth of the Kerala economy in general and agriculture in particular since the mid‐1970s, the ‘trickle down’ theory cannot explain the decline in poverty. Similarly, the fact that rural wages have increased faster than the consumer price index does not constitute a sufficient condition for crossing the poverty line. Expansion of state‐directed programmes is seen to be the single most important determinant in reducing rural poverty. The effect of public intervention programmes is roughly estimated to be equal to one fifth of the consumption of rural labour households. The lesson of Kerala for poverty alleviation is that social protection expressed in terms of meeting the basic consumption requirements of the poor, especially the vulnerable among the poor, should be a necessary component of development policy. However, this is not a sufficient condition: there should also be a growth strategy which would provide adequate employment to all members of the labour force from the poorer sections of the population. The current line of official thinking in India, in the context of economic liberalization, is hardly conducive to such a strategy.
Minimum Wage Policy, Rural Development and Poverty Alleviation in Malawi
Authors: Livingstone Ian
Published: October 2008

This article examines the pattern of minimum wage changes in Malawi and some of their effects, and considers more generally the appropriateness of a minimum wage policy in developing country situations similar to that of Malawi. After a progressive decline in the real value of the minimum wage during the 1970s there is evidence that the government is attempting, through periodic and rather erratic corrective action, to maintain something like a constant real wage. Data from a Ministry of Labour survey demonstrate that such changes in the minimum wage do have a direct effect on wages paid, but that this is concentrated in specific sectors: outside these, minimum wage policy is ineffectual, and the effective coverage achieved in terms of the national work‐force is very narrow. Since the most significant influence on the wages of hired workers is the elastic supply of unskilled labour available at very low wages from the smallholder sector, efforts need to be concentrated on raising the supply price of labour through positive policies pursued in the rural sector. Some special features of the rural labour market are therefore examined. Various measures could be taken here: one which seems likely to be effective in producing immediate results is the progressive transfer of burley tobacco quotas to smallholders.
Institutionalizing Participatory, Client‐Driven Research and Technology Development in Agriculture
Authors: Ashby Jacqueline A. , Sperling Louise
Published: October 2008

This article identifies key characteristics of participatory research and development(R&D) in the agricultural sector: it is client‐driven, requires decentralized technology development, devolves to farmers the major responsibility for adaptive testing, and requires institutions and individuals to become accountable for the relevance and quality of technology on offer. Through case study material drawn from Latin America, Asia and Africa, the article then reviews ways by which institutions have responded to these characteristics and raises issues for further elaboration. Steps need to be taken, in particular, to safeguard equity, both between the more and less vocal groups of farmers, and between the requirements of present and future generations (the latter referring particularly to environmental concerns). It is argued that participatory R&D alone is insufficient to deliver innovations relevant to diverse client groups: policy mechanisms are required to define which clients are to participate, whose agendas are to drive the process, and what organizational innovations are needed to move agricultural R&D in these directions.
Land Reforms at Centre Stage: The Evidence on West Bengal
Authors: Lieten G.K.
Published: October 2008

The debate on the agrarian problem in developing countries has alternated between a stress on the necessity for land reforms and an emphasis on the introduction of productivity‐enhancing technology, leading to a trickle‐down effect. In the Indian state of West Bengal, the former strategy has been pursued since the mid‐1970s. Most observers agree that this approach has stimulated a ‘virtuous circle’, leading to higher production, a decrease in poverty and in polarization, and a perceptible improvement of the human development index. This article addresses the causality sequence, namely, whether land reform or irrigation has acted as the kick‐start mechanism to these improvements. The irrigation figures are not impressive, either in comparison with the outlay in other Indian states, or in terms of crop coverage. The explanation for activation of a virtuous circle may therefore be found in land reform, at least if land reform is considered and implemented in its comprehensive meaning: intervention in the relations of production, the forces of production and the broad social and political parameters.
Spatial Disparities and Economic Development in China, 1953‐92: A Comparative Study
Authors: Xiaobin Simon Zhao
Published: October 2008

It seems to be widely accepted that China's interior development during the Maoist period was based on ‘equality’ considerations, which narrowed Chinese regional disparities. By contrast, the recent coastal development during Deng's reform era has been coined as ‘uneven’ and ‘undesirable’, because it has created tremendous inequalities across the country. However, the findings of this study suggest that the question may not be that simple. This article examines the spatial disparities of economic development in China between 1953 and 1992, focusing on a time‐series comparison between the development policies of Mao and Deng, their outcomes and the resulting changes. By using provincial and regional economic and investment data, the article elaborates why Mao's interior development did not lead to a more equitable outcome than Deng's uneven strategy of’ east coastal development’. The findings provide an insight into some of the unexpected outcomes of more than forty years of socialist development, in the realm of economic growth and disparity.
The National Question in Africa: Internal Imperatives
Authors: Soyinka Wole
Published: October 2008

In an impassioned plea for political reform in Africa, this essay questions whether the concept of ‘nation‐being’ is really applicable to territories ruled by dictatorial regimes. Without democracy, many African ‘nations’ are little more than a gambling space for the opportunism and adventurism of power. Furthermore, as in the concrete case of Nigeria, repression strengthens ethnic identity and encourages separatism. The risks of virulent ethnic conflict in Africa — and elsewhere — might be lessened if regional conferences were called to debate the national question openly, and to redefine (where necessary) both the external boundaries and the internal political realities of conflict‐ridden societies.
The Debate on Economic and Social Security in the Late Eighteenth Century: Lessons ofa Road Not Taken
Authors: Rothschild Emma
Published: October 2008

The laissez faire political economy of the late eighteenth century was marked by two sharply opposing views of the relation between social security or insecurity and economic growth: one associated with Adam Smith, Turgot and Condorcet; and another associated with Malthus. The latter school, with its faith in the motivating force of insecurity and fear, has been the more influential in subsequent economic thought. But, contrary to prevailing neoliberal stereotypes, Smith, Turgot and Condorcet had much to say to modern students of economics concerning the necessary and positive relationship between social security and economic development. This essay explores their vision of how to improve the life chances of the disadvantaged.
Traditional Co‐operatives in Modern Japan: Rethinking Alternatives to Cosmopolitanismand Nativism
Authors: Najita Tetsuo
Published: October 2008

The history of contract co‐operatives in Japan, from the eighteenth century to the modern era, illustrates how local people have created long‐standing institutions ensuring solidarity and security in times of emergency. Village cooperatives, developed entirely outside the framework of public administration or legal regulation, were based on moral contracts of mutual protection against misfortune. Functioning over hundreds of years, they have reflected an ethic of reverence for life which is neither traditional nor modern, nor circumscribed to cultures of East or West. It is a universal value particularly worthy of emphasis in these times of sharpening cultural division and conflict.
On the Social Costs of Modernization. Social Disintegration, Atomie/Anomie and SocialDevelopment
Authors: Galtung Johan
Published: October 2008

This essay presents a provocative and pessimistic picture of the human condition at the end of the twentieth century. Many societies are seen to be caught up in a process of destructuration and deculturation, heading for structurelessness and culturelessness — here defined as ‘atomie’ and ‘anomie’. This is accompanied by a collapse and corruption of institutions, an isolation of individuals and the growing predominance of purely egotistical motivation for action. In the cultural sphere, modernization seems either to have entirely undermined religious belief or encouraged an intolerant fundamentalist backlash. One way to reverse this apparent slide toward anomie might be to draw upon the connecting, unifying force of all tolerant and compassionate religions.
The Political Economy of Inappropriate Technology: Industrialization in Sub‐Saharan Africa
Authors: James Jeffrey
Published: October 2008

The failure of public sector investment projects in Sub‐Saharan Africa can often be described in large measure as a technological one, where technology is defined not just in the narrow sense of alternative factor proportions, but in the wider terms of scale and import intensity as well. In confining itself mainly to the economic dimensions of the problem, the existing literature fails to consider the reasons for the extraordinarily rapid and widespread expansion of the public sector in Sub‐Saharan Africa and it hence ignores the possibility that this expansion might itself be related to the observed patterns of technological behaviour in the sector. Such a possibility, I suggest, resides in the political and institutional compulsions that drive industrial firms in the public sector to increase the size of their operations.
Democracy, Equity and Common Property Resource Management in the Indian Subcontinent
Authors: Blair Harry W.
Published: October 2008

This article addresses the relationship between democracy, equity and common property resource management in South Asia, both at the national and at the local level. Its substantive focus will be largely on forests, and its geographical concentration mostly on India, although other sectors (primarily water) and areas (Nepal and Bangladesh) will also be included. The article opens by looking at Garrett Hardin's (1968) three strategies to preserve the commons. It finds that democratic politics is compatible with both privatization and centralization as conserving strategies (although not necessarily successful). With the third approach—local control—democracy has at best a problematic relationship, for where governmental units are the relevant actors, there tends to be more interest in consuming than in conserving or preserving resources at the local level. Local user groups, however, do much better at common property resource management, because they can restrict membership and thus avoid free riders, and they can establish a close linkage in their members' minds between benefits and costs of participating in group discipline to maintain the resource.
Redemocratization and Decentralization in Brazil: The Strength of the Member States
Authors: Souza Celina
Published: October 2008

With redemocratization and the promulgation of the 1988 Constitution, Brazil became highly decentralized in terms of the distribution of financial revenue and political strength. As a result, sub‐national governments, and especially the states, are now at the centre of the political and financial scene. In the absence of party‐oriented politics, regional politicians, and particularly the state governors of the most important states, provide the federal government with ruling coalitions. The central question addressed in this article is what the state governments and their politicians are doing with this political and financial strength. A further point made is the importance of incorporating the states into the framework of analysis of decentralization: at the state level it is possible to identify a number of details about processes which remain too general at the national level and too specific at the local level. Brazil's experience in a decade of political and financial decentralization shows that although decentralization fosters democracy, a variety of other political and economic factors are also of influence, thus exposing the limits of decentralization's impact on policy results.
Culture and Development Ethics: Needs, Women's Rights, and Western Theories
Authors: Gasper Des
Published: October 2008

Can development ethics avoid presuming that European cultures have universal validity and yet also avoid treating every distinct culture as sacrosanct and beyond criticism? While work on ‘culture and development’ valuably stresses the importance of cultural differences and identity it has often been hindered by conceptual limitations when faced with the ambiguities, variety, conflict and change within societies. This article queries a communitarian belief, that morality cannot be anything other than whatever a community's norms are, and suggests that recent development ethics work usefully blends universalist ethics with room for local traditions and choices. As advances on both (a) forms of liberalism that are universalist in scope but Eurocentric and over‐individualistic in content, and (b) relativist forms of communitarian or post‐modern ethics, three current approaches are noted: new work on Basic Human Needs theory, including Amartya Sen's capabilities approach; Martha Nussbaum's Aristotelian extension of Sen; and Onora O'Neill's Kantian development ethic. Particular attention is paid in the article to disputes concerning women's rights.
Trade Liberalization and Export Performance in Bolivia
Authors: Jenkins Rhys
Published: October 2008

One of the anticipated gains from the trade liberalization policies adopted by many Latin American countries in recent years is improved export performance. In this article, the arguments on which this expectation is based are reviewed and the impact of trade liberalization on Bolivian manufactured exports analysed. The conclusion is that improved export performance is largely the result of a more realistic and more stable real exchange rate after 1985, while the trade policy reforms have had little impact. Certain deficiencies of Bolivia's export performance, such as the increased emphasis on primary and semi‐processed products, and the lack of diversification in terms of both products and markets, are also noted.
Diagonal Recurrent Neural Networks for MDOF Structural Vibration Control
Authors: Gu Z. Q. , Oyadiji S. O.
Published: October 2008

In recent years, considerable attention has been paid to the development of theories and applications associated with structural vibration control. Integrating the nonlinear mapping ability with the dynamic evolution capability, diagonal recurrent neural network (DRNN) meets the needs of the demanding control requirements in increasingly complex dynamic systems because of its simple and recurrent architecture. This paper presents numerical studies of multiple degree-of-freedom (MDOF) structural vibration control based on the approach of the backpropagation algorithm to the DRNN control method. The controller’s stability and convergence and comparisons of the DRNN method with conventional control strategies are also examined. The numerical simulations show that the structural vibration responses of linear and nonlinear MDOF structures are reduced by between 78% and 86%, and between 52% and 80%, respectively, when they are subjected to El Centro, Kobe, Hachinohe, and Northridge earthquake processes. The numerical simulation shows that the DRNN method outperforms conventional control strategies, which include linear quadratic regulator (LQR), linear quadratic Gaussian (LQG) (based on the acceleration feedback), and pole placement by between 20% and 30% in the case of linear MDOF structures. For nonlinear MDOF structures, in which the conventional controllers are ineffective, the DRNN controller is still effective. However, the level of reduction of the structural vibration response of nonlinear MDOF structures achievable is reduced by about 20% in comparison to the reductions achievable with linear MDOF structures.
Transient Method for Convective Heat Transfer Measurement With Lateral Conduction—Part I: Application to a Deposit-Roughened Gas Turbine Surface
Authors: Bons J.
Published: October 2008

The effect of lateral conduction on convective heat transfer measurements using a transient infrared technique over a rough surface is evaluated. The rough surface is a scaled model of gas turbine surface deposits. Comparisons are made between a full 3D finite volume analysis and a simpler 1D transient conduction model. The surface temperature history was measured with a high resolution infrared camera during an impulsively started hot gas flow over the rough test plate at a flow Reynolds number of 750,000. The boundary layer was turbulent with the peak roughness elements protruding just above the boundary layer momentum thickness. The 1D model underestimates the peak to valley variations in surface heat flux by up to a factor of 5 compared with the 3D model with lateral conduction. For the area-averaged surface heat flux, the 1D model predicts higher values than a 3D model for the same surface temperature history. This is due to the larger surface area of the roughness peaks and valleys in the 3D model, which produces a larger initial input of energy at the beginning of the transient. For engineering purposes, where the net heat load into the solid is desired, this lower 3D model result must be multiplied by the wetted-to-planform surface area ratio of the roughness panel. For the roughness model in this study, applying this correction results in a 25% increase in the area-averaged roughness-induced Stanton number augmentation for the 3D rough surface model compared with a flat 1D surface model at the same Reynolds number. Other shortcomings of the transient method for rough surface convective heat transfer measurement are identified.
Analytical Solution of Nonequilibrium Heat Conduction in Porous Medium Incorporating a Variable Porosity Model With Heat Generation
Authors: Nazari M. , Kowsary F.
Published: October 2008

This paper is concerned with the conduction heat transfer between two parallel plates filled with a porous medium with uniform heat generation under a nonequilibrium condition. Analytical solution is obtained for both fluid and solid temperature fields at constant porosity incorporating the effects of thermal conductivity ratio, porosity, and a nondimensional heat transfer coefficient at pore level. The two coupled energy equations for the case of variable porosity condition are transformed into a third order ordinary equation for each phase, which is solved numerically. This transformation is a valuable solution for heat conduction regime for any distribution of porosity in the channel. The effects of the variable porosity on temperature distribution are shown and compared with the constant porosity model. For the case of the exponential decaying porosity distribution, the numerical results lead to a correlation incorporating conductivity ratio and interstitial heat transfer coefficient.
Mixed Convection in a Vertical Microannulus Between Two Concentric Microtubes
Authors: Avcı Mete , Aydın Orhan
Published: October 2008

In this study, fully developed mixed convective heat transfer of a Newtonian fluid in a vertical microannulus between two concentric microtubes is analytically investigated by taking the velocity slip and the temperature jump at the wall into account. The effects of the mixed convection parameter Gr/Re, the Knudsen number Kn, and the aspect ratio r* on the microchannel hydrodynamic and thermal behaviors are determined. Finally, a Nu=f(Gr∕Re,Kn,r*) expression is developed. It is disclosed that increasing Gr/Re enhances heat transfer while rarefaction effects considered by the velocity slip and the temperature jump in the slip flow regime decreases it.
Analytical Solution to Transient Asymmetric Heat Conduction in a Multilayer Annulus
Authors: Jain Prashant K. , Singh Suneet , Rizwan-uddin
Published: October 2008

In this paper, we present an analytical double-series solution for the time-dependent asymmetric heat conduction in a multilayer annulus. In general, analytical solutions in multidimensional Cartesian or cylindrical (r,z) coordinates suffer from existence of imaginary eigenvalues and thus may lead to numerical difficulties in computing analytical solution. In contrast, the proposed analytical solution in polar coordinates (2D cylindrical) is “free” from such imaginary eigenvalues. Real eigenvalues are obtained by virtue of precluded explicit dependence of transverse (radial) eigenvalues on those in the other direction.
Forced Convection Flow in a Wavy Channel With a Linearly Increasing Waviness at the Entrance Region
Authors: Alawadhi Esam M.
Published: October 2008

This research studies the fluid flow and heat transfer in a wavy channel with a linearly increasing waviness at the entrance region. The considered model consists of a channel formed by two wavy plates described by a sinusoidal profile and maintained at a uniform temperature. The finite element method is utilized to solve the problem. Reynolds numbers are considered in the range of 125<Re<1000 to avoid unsteady flow, and Pr=0.7. The global objective of this research is to reduce the pressure drop in the wavy channel due to the developing flow at the entrance region. The effect of the Reynolds number, length of the increasing waviness region, waviness of the wavy wall on the hydrodynamics, and thermal characteristics of the channel is investigated. The result indicates that the linearly increasing waviness at the entrance region significantly reduces the pressure drop in the channel on the other hand, the thermal characteristics of the wavy wall are nearly unaffected.
Vibration Damping in Structures With Layered Viscoelastic Beam-Plate
Authors: Olunloyo Vincent O. S. , Osheku Charles A. , Damisa O.
Published: October 2008

Vibration and noise reduction in structures can significantly enhance dynamic stability. In fact, exploitation of such mechanisms can lead to an improvement of aerodynamic performance in flight motions by aircrafts, hydrodynamic performance in ocean water navigation by ships or floating structures, as well as dynamic behavior of machine structures in production processes and systems. In this paper slip damping with layered viscoelastic beam-plate structures for dissipation of vibration energy in aircraft, hydrodynamic, and machine structures is investigated analytically. For this problem, a boundary value partial differential equation is formulated via contact mechanics. In particular, the effect of interfacial pressure distribution variation at the interface of the layered structures on the energy dissipation and logarithmic damping decrement with such layered structures is analyzed and presented for design applications. This allows for a better understanding of the selection process of viscoelastic damping materials for such structures.
Wave Analysis of In-Plane Vibrations of H- and T-shaped Planar Frame Structures
Authors: Mei C.
Published: October 2008

This paper concerns in-plane vibration analysis of coupled bending and longitudinal vibrations in H- and T-shaped planar frame structures. An exact analytical solution is obtained using wave vibration approach. Timoshenko beam theory, which takes into account the effects of both rotary inertia and shear distortion, is applied in modeling the flexural vibrations in the planar frame. Reflection and transmission matrices corresponding to incident waves arriving at the “T” joint from various directions are obtained. Bending and longitudinal waves generated by a combination of point longitudinal forces, point bending forces, and bending moments are also obtained. Assembling these wave relations provides a concise and systematic approach to both free and forced vibration analyses of coupled bending and longitudinal vibrations in H- and T-shaped planar frame structures. Natural frequencies, modeshapes, and forced responses are obtained from wave vibration standpoint. The results are compared to results available in literature. Good agreement has been reached.
Eigenfrequencies of an Arbitrarily Supported Beam Carrying Multiple In-Span Elastic Rod-Mass Systems
Authors: Cha Philip D. , Chan Michael , Nielsen Gregory
Published: October 2008

Many vibrating mechanical and structural systems consist of a host structure to which a number of continuous attachments are mounted. In this paper, an efficient method is proposed for determining the eigenfrequencies of an arbitrarily supported Euler–Bernoulli beam with multiple in-span helical spring-mass systems, where the mass of the helical spring is considered. For modeling purposes, each helical spring can be modeled as an axially vibrating elastic rod. The traditional approach of using the eigenfunctions of the beam and rod in the assumed modes method often leads to an intolerably slow convergence rate. To expedite convergence, a spatially linear-varying function that corresponds to the static deformed shape of a rod is included in the series expansion for the rod. The proposed approach is systematic to apply, easy to code, computationally efficient, and can be easily modified to accommodate various beam boundary conditions. Numerical experiments show that with the addition of a spatially linear-varying function, the proposed scheme converges very quickly with the exact solution.
Modal Analysis of Rubbing Acoustic Emission for Rotor-Bearing System Based on Reassigned Wavelet Scalogram
Authors: He Yongyong , Yin Xinyun , Chu Fulei
Published: October 2008

Rubbing between the rotor and the stator is the frequent and harmful malfunction in the rotating machinery, which will cause a very serious accident, even catastrophe, to the machine. Thus, such fault needs timely detection to avoid severe consequences. Vibration based methods are the traditional ones for the detection and diagnosis of the rubbing fault, which are effective when the rubbing has been severe, but always do not work in early detection of such fault. Rubbing between the rotor and the stator will cause elastic strain in the rubbing location and thus can produce acoustic emission (AE). Apparently, such AE contains direct and abundant information about the rubbing and thus can be used to detect and diagnose such fault effectively. In this paper, the AE based method is proposed for detecting and identifying the rubbing of the rotor-bearing system. Using the modal acoustic emission (MAE) theory and reassigned wavelet scalogram, the present study emphasizes on modal analysis and time-frequency characteristics analysis for further understanding the characteristics, phenomenon, and features of the rubbing AE. The results show that the rubbing AE is the elastic wave with multiple modals, which has an impact characteristic and mainly consists of the flexural wave and extensional wave. The transmission of the rubbing AE has some directivity. Moreover, different modals have different transmission characteristics: The flexural wave has lower frequency and its attenuation is influenced mainly by the sectional area of the transmission passage. The extensional wave has higher frequency and its attenuation is mainly sensitive to the interface transmission between the two surfaces. The results also reveal that the reassigned wavelet scalogram is more effective than its original scalogram for the characteristic analysis of the rubbing AE.
Modeling of Electrodynamic Bearings
Authors: Amati Nicola , De Lépine Xavier , Tonoli Andrea
Published: October 2008

A new model of electrodynamic bearings is presented in this paper. The model takes into account the R-L dynamics of the eddy currents on which this type of bearing is based, making it valid for both quasistatic and dynamic analyses. In the quasistatic case, the model is used to obtain the force generated by an off-centered shaft rotating at a fixed speed in a constant magnetic field. The model is then used to analyze the dynamic stability of a Jeffcott rotor supported by electrodynamic bearings. The essential role played by nonrotating damping in ensuring a stable operating range to the rotor is studied by means of root loci. Comparison with literature results is finally used to validate the model.
Developing Nonthermal-Equilibrium Convection in Porous Media With Negligible Fluid Conduction
Authors: Dukhan Nihad
Published: October 2008

In certain contemporary technologies, porous media with high solid-phase conductivity are impregnated with low-conductivity fluids, e.g., metal and graphite foam cooled by air. For such cases, an approximate analytical model for the developing heat transfer inside a two-dimensional rectangular porous medium subjected to constant heat flux is presented. The model neglects conduction in the fluid and assumes plug flow. The resulting nonthermal-equilibrium equations are solved for the solid and fluid temperatures by separation of variables. The temperatures decay exponentially as the distance from the heated base increases. The effects of the Biot and Peclet numbers are presented. Fully developed heat-transfer conditions are achieved at an axial distance equal to five times the height of the porous medium, with a constant Nusselt number equal to 3.
Numerical Investigation of Electrohydrodynamic-Conduction Pumping of Liquid Film in the Presence of Evaporation
Authors: Yazdani Miad , Seyed-Yagoobi Jamal
Published: October 2008

Electrohydrodynamic (EHD) conduction pumping is associated with the heterocharge layers of finite thickness in the vicinity of the electrodes, generated by the process of dissociation of the neutral electrolytic species and the recombination of the generated ions. This paper numerically investigates the EHD-conduction pumping of a liquid film in the presence of evaporation. The flow system comprises a liquid film flowing over a two-dimensional flat plate. The vapor phase above the flat plate is extended far beyond the interface. The channel is separated into four different sections: the entrance, electrode, evaporation, and downstream sections. The entrance, electrode, and downstream regions are adiabatic while a constant heat flux is applied in the evaporation section. The concept of EHD-conduction pumping of liquid film in the presence of phase change is numerically demonstrated in this paper. The resultant heat transfer due to conduction pumping is evaluated as well. The results for heat transfer coefficient along the channel indicate considerable improvement of heat transfer coefficient compared with the pressure-driven counterpart.
Radiative Properties of Expanded Polystyrene Foams
Authors: Rémi Coquard , Dominique Baillis , Daniel Quenard
Published: October 2008

Expanded polystyrene foams are one of the most widely used materials for a building’s thermal insulation. Owing to their very low density, a substantial proportion of the heat transfer is due to thermal radiation propagating through their porous structure. In order to envisage an optimization of their thermal performances, an accurate modeling of their radiative behavior is required. However, the previous studies on this subject used several drastic simplifications regarding their radiative behavior (optically thick material) or their porous morphology (homogeneous cellular material, dodecahedral cells). In this study, we propose a more accurate model based on a detailed representation of their complex morphology allowing us to predict their entire monochromatic radiative properties. We investigated the influence of the different structural parameters on these properties. We checked the validity of our model by comparing the spectral hemispherical reflectance and transmittance measured on slabs of foam samples with values predicted by our model. A good accordance was found globally.
Privacy-preserving classification of vertically partitioned data via random kernels
Authors: Mangasarian Olvi L. , Wild Edward W. , Fung Glenn M.
Published: October 2008

We propose a novel privacy-preserving support vector machine (SVM) classifier for a data matrixAwhose input feature columns are divided into groups belonging to different entities. Each entity is unwilling to share its group of columns or make it public. Our classifier is based on the concept of a reduced kernelK(A,B′), whereB′ is the transpose of a random matrixB. The column blocks ofBcorresponding to the different entities are privately generated by each entity and never made public. The proposed linear or nonlinear SVM classifier, which is public but does not reveal any of the privately held data, has accuracy comparable to that of an ordinary SVM classifier that uses the entire set of input features directly.