Transition Shock Research Articles

Experimental and computational investigations of hypersonic flow about compression ramps

Comprehensive results of a joint experimental and computational study of the two-dimensional flow field over flat plate/compression ramp configurations at Mach 14 are presented. These geometries are aimed to simulate, in a simplified manner, the region around deflected control surfaces of hypersonic re-entry vehicles. The test cases considered cover a range of realistic flow conditions with Reynolds numbers to the hinge line varying between 4.5 × 105 and 2.6 × 106 (with a reference length taken as the distance between the leading edge and the hinge line) and a wall-to-total-temperature ratio of 0.12. The combination of flow and geometric parameters gives rise to fully laminar strong shock wave/boundary layer interactions with extensive separation, and transitional interactions with transition occurring near the reattachment point. A fully turbulent interaction is also considered which, however, was only approximately achieved in the experiments by means of excessive tripping of the oncoming hypersonic laminar boundary layer. Emphasis has been placed upon the quality and level of confidence of both experiments and computations, including a discussion on the laminar-turbulent transition process and the associated striation phenomenon. The favourable comparison between the experimental and computational results has profided the grounds for an enhanced understanding of the relevant flow processes and their modelling. Particularly in relation to transitional shock wave/boundary layer interactions, where laminar-turbulent transition is promoted by the adverse pressure gradient and flow concavity in the reattachment region, a method is proposed to compute extreme adverse effects in the interaction region avoiding such inhibiting requirements as transition modelling or turbulence modelling over separated regions.

An elasticity approach to the analysis of Romanian foreign trade policy during the years of transition

This paper focuses on the effect of exchange rate variations on the economic evolution of a country in transition, facing inflation, output decrease and negative external shocks; the particular case of Romania is considered. The theoretical part is linked to the Fleming-Mundell model for an open economy, but additional assumptions of price mobility and capital immobility are introduced. The usual interest rate versus output graphic framework is switched from one to another, which plots the exchange rate (or real exchange rate) versus output; the author considers that such a representation fits the behavior of an economy in transition towards a market-based system better. A main role, according to this interpretation, is played by the exchange rate elasticities of imports and exports, which influence the images of the equilibria on the goods market and the balance of payment (the IS and BOP curves' slopes). Finally, an empirical analysis is made, as an example, on the Romanian energy imports data series; the attempts to calculate the exchange rate elasticity may be considered as reliable only in the short term. In order to estimate the global exchange rate elasticities of imports and exports, some aggregations of partial sectorial results might be a possible solution. In the Romanian case, the resulting elasticities seem to be lower than for other countries; this poses the question as to the effectiveness of exchange rate policies in managing the Romanian economy.

Scattering behavior of transitional shock waves

We study the stability and asymptotic behavior of transitional shock waves as solutions of a parabolic system of conservation laws. In contrast tp classical shock waves, transitional shock waves are semitive to the precise form of the parabolic term, not only in their internal structure but also in terms of the end states that they connect. In our numerical investigation, these waves exbibit robust stability. Moreover, their response to perturbation differs from that of classical waves; in particular, the asymptotic state of a perturbed transitional wave depends on the location of the perturbation relative to the shock wave. We develop a linear scattering model that predicts behavior agreeing quantitatively with our numerical results.

Environmental Testing of a Blood Gas/pH and Electrolyte Analyzer for Field Hospital Use

In 1983 the U.S. Army Academy of Health Sciences developed a Letter Requirement for a Blood Gas/pH Analyzer for use in Echelon 3 and 4 facilities. Field trials of several nondevelopment items and a subsequent market survey did not produce a suitable instrument. Recently, a relatively small, lightweight, and simple device became commercially available, and was tested for field applicability in accordance with MIL-STD-810D. Results indicated that with minor modifications, the instrument would be sufficiently rugged to withstand the severe storage temperature extremes and transit shock and vibration conditions associated with deployment of field medical materiel.

Transition Shock: Can the East Get There from Here?

After sudden political liberalization, Eastern Europe and the Soviet Union seem poised to abandon administrative-command planning and embrace market socialism (which stops somewhere short of American-style capitalism). However, using the Soviet Union as a case in point, careful analysis of all plausible transition paths from the current system to Westernstyle markets suggests that prospects for success are dim. The revolution of rising expectations in the Soviet Union and Eastern Europe sparked by Gorbachev's program of political liberalization is on a collision course with the immediate possibilities for fundamental economic change. The East is likely to be politically unstable for a long period, nor can the West alter this situation with massive foreign assistance because the Eastern nations cannot utilize the credits effectively. The Western business community therefore must be very constrained in its expectations about progress in the East and should approach the issues of private investment and governmental aid accordingly.

Transitional Waves for Conservation Laws

A new class of fundamental waves arises in conservation laws that are not strictly hyperbolic. These waves serve as transitions between wave groups associated with particular characteristic families. Transitional shock waves are discontinuous solutions that possess viscous profiles but do not conform to the Lax characteristic criterion; they are sensitive to the precise form of the physical viscosity. Transitional rarefaction waves are rarefaction fans across which the characteristic family changes from faster to slower.This paper identifies an extensive family of transitional shock waves for conservation laws with quadratic fluxes and arbitrary viscosity matrices; this family comprises all transitional shock waves for a certain class of such quadratic models. The paper also establishes, for general systems of two conservation laws, the generic nature of rarefaction curves near an elliptic region, thereby identifying transitional rarefaction waves. The use of transitional waves in solving Riemann problems...

Transition Shock and the Relocation of People from Mental Handicap Hospitals and Hostels

AbstractThe process of deinstitutionalisation has been gathering momentum in Britain and the United States since the mid‐1970s. A discussion of these trends provides the background to an examination of “transition shock” as it affects people relocated from mental handicap institutions. The paper explores the theoretical underpinnings of the concept of transition shock and links them to the findings of a follow‐up study of the behavioural consequences of relocation.

A Social Psychological Model of the Schooling Process Over First Grade

Children's experiences during the first grade, as they pass through a key life-cycle transition, are an especially critical but generally neglected period in the sociology of development. This paper examines the process of educational achievement for a birth cohort of Baltimore children followed prospectively over their first-grade year. Employing a social-psychological model of the early schooling process, the analysis identifies some of the personal, interpersonal, and situational factors that influence cognitive development during this period of transition from home child to school child. Gains on standardized tests of verbal and mathematical competence are used as achievement criteria. Black children experienced more transition shock than white children in making the move into full-time schooling, as indicated by their lower initial report card marks and slower pace of cognitive growth during the year. The processes determining the achievement of the two groups also were somewhat different. Personalityltemperament variables turned out to be very important for early schooling; evidence was found as well for the efficacy of parents as significant others. Self-expectations had effects only on verbal test performance; there was no indication of peer influence during this important settling-in period. Implications of these findings for models of development and for understanding the social psychological basis of the achievement process are discussed.

Dynamic compression and volatile release of carbonates

Particle velocity profiles upon shock compression and adiabatic release were measured for polycrystalline calcite (Solenhofen limestone) to 12–24 GPa and for porous calcite (Dover chalk, ρo = 1.40 g/cm3, 49% porosity) to between 5 and 11 GPa. The electromagnetic particle velocity gauge method was used. Upon shock compression of Solenhofen limestone, the Hugoniot elastic limit was determined to vary from 0.36 to 0.45 GPa. Transition shocks at between 2.5 and 3.7 GPa, possibly arising from the calcite II‐III transition, were observed. For the Solenhofen limestone, the release paths lie relatively close to the Hugoniot. Evidence for the occurrence of the calcite III‐II transition upon release was observed, but no rarefaction shocks were detected. Initial release wave speeds suggest retention of shear strength up to at least 20 GPa, with a possible loss of shear strength at higher pressures. The measured equation of state is used to predict the fraction of material devolatilized upon adiabatic release as a function of shock pressure. The effect of ambient partial pressure of CO2 on the calculations is demonstrated. P CO2 should be taken into account in models of atmospheric evolution by means of impact‐induced mineral devolatilization. Mass fractions of CO2 released expected on the basis of a continuum model are much lower than determined experimentally. This discrepancy, and radiative characteristics of shocked calcite, indicate that localization of thermal energy (shear banding) occurs under shock compression even though no solid‐solid transitions occur in this pressure range. Release adiabatic data indicate that Dover chalk loses its shear strength when shocked to 10 GPa pressure. At 5 GPa the present data are ambiguous regarding shear strength. For Dover chalk, continuum shock entropy calculations result in a minimum estimate of 90% devolatilization upon complete release from 10 GPa. For calcite, isentropic release paths from calculated continuum Hugoniot temperatures cross into the CaO (solid) + CO2 (vapor) field at improbably low pressures (for example, 10 GPa for a shock pressure of 25 GPa). However, calculated isentropic release paths originating from PT points corresponding to previous color temperature under shock measurements cross into the melt plus vapor field at pressures greater than 0.5 GPa, suggesting that devolatilization is initiated at the shear banding sites.

A critical examination of intra-agency relocation effects.

Behavioral effects of intrainstitutional relocation of adults with mental retardation were evaluated over a 12-month period using two independent methods of measurement and a multiple baseline across two relocating groups and one matched control group. Clients grouped together on the basis of relatively high levels of aggressive or destructive behavior exhibited an increase in social isolation following relocation. However, as a whole, relocation effects were subtle and individualized in nature. Behavior adjustment following relocation and methods for avoiding "transition shock" following rapid environmental change are discussed.

De‐institutionalisation and the Intellectually Handicapped Part I: The Concept of Transition

The non‐handicapped person displays particular behaviours when moving from one situation to another. These behaviours are compared to the behaviours of intellectually handicapped adults who are in transition from home to an institution or from the institution to the community. Family crisis theory is discussed relative to the family's loss or gain of an intellectually handicapped member. Possible implications of behaviours during ‘transition shock’ are presented for the intellectually handicapped person and staff in an institution, with recommendations for a more specific assessment of needs to facilitate the transition process.

Electron oscillations of a collisionless plasma in a static electric field

The influence of a static electric field on electron oscillations of (i) a cold beam of electrons and (ii) a hot non-drifting plasma is investigated. The importance of the relative strength of the field is emphasized. In the weak field limit the oscillations are adiabatic, manifested by the existence of adiabatic invariants, preservation of eigenmodes and absence of reflexion. If the field is strong, however, interesting new features, such as mutual coupling of eigenmodes and wave reflexion, appear. Possible stability properties of a monotonic electrostatic transition (shock, double layer) are also discussed.

Urbanization as a Source of Political Disaffection--The Jamaican Experience

Various studies of Latin American politics have attempted to establisl a relationship between urbanization as a process of social change and political and social disaffection. This paper attempts to re-examine the thesis regarding the disruptive effect of rapid urbanization on support for political authority in the context of recent Jamaican experience. A number of studiesl of a macro level and aggregate data character have suggested a positive link between rapid and extensive urbanization and political and social disorder. Recently, however, these findings have been challenged by survey research2 and anthropological studies3 of Latin American societies. The central theme of this body of analysis has been the adaptation and integration of 'marginal' rural-to-urban migrants within large metropolitan and increasingly ghettoized urban centres containing huge areas of impoverished squatter settlements. Nelson, Cornelius and Lewis have all presented data which repudiate the view of the rural to urban squatter settler as a maladjusted, socially frustrated, anomic, rootless and culturally displaced militant. These migrants, they argue, form an integral part of the urban social structure who are no less integrated into the urban social and political environment than are the urban born city population. Some of the analysis advanced to account for this level of adjustment to the urban environment includes the migrants' easy cooptation into urban patronclient politics; their low levels of material and social expectations; and the preservation of their strong integrative social institutions such as the extended family and religious activity. Additional arguments refer to a migration pattern that filters migrants through a series of less urbanized to more urbanized communities thereby reducing the culture shock of transition from rural to urban areas; the sheer size of the rural movement into the urban areas which represents a ruralization of the urban environment; and the migrants' general apolitical orientatiorl based on a prior and total concern with individual and day to day

Pre- Theological Training: An Empirical Study

which holds promise of creative results in the field of theological education. What is the place of the college and university in the over-all program of theological education? What should be the relationship between the college and the seminary ? What role should the undergraduate institution play in the preparation of students for religious vocations ? What place should a Department of Religion have in all of this? These and similar questions are the active ingredients in this ferment which was reflected in the recent report to the NABI of its special committee on Pre-Theological Studies.' This discussion has been going on for several years, and the problem is beginning to achieve some form and clarity.2 It is readily admitted, however, by many who are engaged in this discussion that one of the great inadequacies of the analysis is the lack of empirical data. The Niebuhr committee, in its excellent study of theological education in the United States and Canada, has come closest to supplying this need, but it devotes only seven pages to the college and university as an area of theological concern.3 The special committee of the NABI has been instructed to continue its study along such inductive lines, and it is in anticipation of this project that the following material is presented. The purpose here is to suggest some of the relevant questions that need to be asked, and certain lines of empirical investigation along which answers might ultimately be found. The basis of this paper is an empirical study conducted by the Department of Religion at the College of Wooster, completed in 1957. It is presented here at the request of the editor of JBR not because of its excellence, but because of the current interest in this question. One might even discover here some of the values of negative education. The survey covered all of the students at Wooster between the years 1952 and 1956 who declared in their senior year their intention of entering some kind of full time religious work. There were two types of questionnaires: one was for those who had majored in Religion at Wooster; the other for those majoring in other subjects. In the former group there were fifty-nine students, twenty of whom responded to the questionnaire. These included two ordained ministers, two elementary school teachers, one YWCA secretary, one secretary to a college dean, two ministers' wives, and twelve students in various theological seminaries. In the latter group forty-four out of eighty-one students responded to the questionnaire.' Sixteen were ordained ministers, three were wives, one was in the army, and the rest were in seminary. This immediately points out some weaknesses in the study. Not only is the control group a small one, but these were not mature people to whom the experiences of professional life had revealed educational inadequacies. Perhaps they might make different responses to such a questionnaire in later years. There is, however, this value in choosing such a control group: the details of college life were still fresh and the shock of transition to seminary was especially vivid. This would suggest that the basic value of the survey lies in its description of what is the best kind of preparation for seminary. What is the best undergrad* J. ARTHUR BAIRD is a member of the Department of Religion in Wooster College. Dr. Baird is the new chairman of the NABI Committee on Pre-Theological Studies which published a significant report in the April, 1959, JBR.

Economic Consequences of War

One influence of war has repeatedly asserted itself in the past—an effect on the costs of production and on the competitive position of the industries and firms of victorious or neutral nations. This subject needs more study, but certain facts suggest a hypothesis, of three parts. First: war expands some industries or concerns, increases their efficiency, enables them to operate, at the end of the struggle, on a comparatively low-cost basis, intensifies their competitive advantages, and improves their position in relation to foreign competitors. Second: war—for the duration—bolsters up some high-cost units by enabling them to sell at a profit all they can produce. The end of the war places such high-cost units at a disadvantage in the process of absorbing the shocks of the transition to a peacetime economy. Third: the history of postwar periods usually exhibits a sharp contest between such low-cost and high-cost enterprises. While “low cost” and “high cost” may refer to the relative positions of units within the same country, in most of this discussion, the terms will be applied to the producers of one country (either victor or neutral) to mean that their costs are low or high in comparison with those of their foreign competitors.

Continuous Stimulations Versus Transitional Shock in the Phototactic Response.

Continuous Stimulations Versus Transitional Shock in the Phototactic Response.