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Robert William Fogel and G. R. Elton. Which Road to the Past? Two Views of History. New Haven and London: Yale University Press, 1983. Pp. vii, 136. Cloth, $14.95. Review by Stephen Kneeshaw of The School of the Ozarks. Emmanuel LeRoy Ladurie. The Mind and Method of the Historian. Translated by Sian Reynolds and Ben Reynolds. Chicago: University of Chicago Press, 1981. Pp. v, 310. Paper, $9.95. Review by Richard Harvey of Ohio University. John E. O'Connor, ed. American History/ American Television: Interpreting the Video Past. New York: Frederick Ungar Publishing Company, 1983. Pp. 463. Cloth, $17.50; Paper, $8.95. Review by D' Ann Campbell of Indiana University. Foster Rhea Dulles & Melvyn Dubofsky. Labor in America: A History. Arlington Heights, Illinois: Harlan Davidson, Inc., 1984. 4th edition. Pp. ix, 425. Cloth, $25.95. Paper, $15.95. Review by Robert W. Dubay of Bainbridge Junior College. Karen Ordahl Kupperman. Roanoke: The Abandoned Colony. Totowa, New Jersey: Rowman & Allanheld, 1984. Pp. viii, 182. Cloth, $24.95; Paper, $12.50. Review by John T. Reilly of Mount Saint Mary College. Kevin O'Reilly. Critical Thinking in American History: Exploration to Constitution. South Hamilton, Massachusetts: Hamilton-Wenham Regional High School, 1983. Pp. 86. Paper, $2.95. Teacher's Guides: Pp. 180. Paper, $12.95; Kevin O'Reilly. Critical Thinking in American History: New Republic to Civil War. South Hamilton, Massachusetts: Hamilton-Wenham Regional High School, 1984. Pp. 106. Paper, $2.95. Teacher's Guide: Pp. 190. Paper, $12.95. Review by James F. Marran of New Trier Township High School, Winnetka, Illinois. Michael J. Cassity, ed. Chains of Fear: American Race Relations Since Reconstruction. Westport, Connecticut: Greenwood Press, 1984. Pp. xxxv, 253. Cloth, $35.00. Review by Ann W. Ellis of Kennesaw College. L. P. Morris. Eastern Europe Since 1945. London and Exeter, New Hampshire: Heinemann Educational Books, 1984. Pp. 211. Paper, $10.00. Review by Thomas T. Lewis, Mount Senario College. John Marks. Science and the Making of the Modern World. Portsmouth, New Hampshire: Heinemann Educational Books, Inc., 1983. Pp. xii, 507. Paper, $25.00. Review by Howard A. Barnes of Winston-Salem State University. Kenneth G. Alfers, Cecil Larry Pool, William F. Mugleston, eds. American's Second Century: Topical Readings, 1865-Present. Dubuque, Iowa: Kendall/ Hunt Publishing Co., 1984. Pp. viii, 381. Paper, $8.95. Review by Richard D. Schubart of Phillips Exeter Academy. Sam C. Sarkesian. America's Forgotten Wars: The Counterrevoltuionary Past and Lessons for the Future. Westport, Connecticut: Greenwood Press, 1984. Pp. xiv, 265. Cloth, $29.95. Review by Richard Selcer of Mountain View College. Edward Wagenknecht. Daughters of the Covenant: Portraits of Six Jewish Women. Amherst: University of Massachusetts, 1983. Pp. viii, 192. Cloth, $17.50. Review by Abraham D. Kriegel of Memphis State University. Morton Borden. Jews, Turks, and Infidels. Chapel Hill and London: University of North Carolina Press, 1984. Pp. x, 163. Cloth, $17.95. Review by Raymond J. Jirran of Thomas Nelson Community College. Richard Schlatter, ed. Recent Views on British History: Essays on Historical Writing Since 1966. New Brunswick: Rutgers University Press, 1984. Pp. xiii, 524. Cloth, $50.00. Review by Fred R. van Hartesveldt of Fort Valley State College. Simon Hornblower. The Greek World, 479-323 B.C. London and New York: Methuen, 1983. Pp. xi, 354. Cloth, $24.00; Paper, $11.95. Review by Dan Levinson of Thayer Academy, Braintree, Massachusetts. H. R. Kedward. Resistance in Vichy France. New York: Oxford University Press, 1978. Paper edition 1983. Pp. ix, 311. Paper, $13.95. Review by Sanford J. Gutman of the State University of New York at Cortland.

Service learning provides students the opportunity to realistically assess the strengths of their professional knowledge and skills while contributing to services that address community needs. Process and product portfolios are proposed as tools for integration of thought and action as students analyze their service learning experiences. Ernest Boyer'S concepts of the scholarship of integration and application are presented here as central to the portfolio development process. Student and faculty reports suggest portfolios are a successful tool for encouraging professional reflection and integration of service learning experiences.

The Microsoft Excel ‘Solver’ tool is a very simple but powerful procedure, even in the hands of the mathematically disadvantaged. It has very good application for quickly fitting experimental flow-curve data to non-Newtonian flow models with any number of parameters, and can cope with data from a number of sources. Examples are given for a range of industrially important examples ranging from standard non-Newtonian liquids, through detergent solutions to gels, pastes, and filled polymer melts, often measured on different viscometers.

A frequent task undertaken by quality-control personnel in typical consumer-goods factories is the measurement of the viscosity of liquid products. The problem often faced in this task is how to strike the correct balance between the complete rheological characterisation of the non-Newtonian properties of the liquid of interest – which requires expensive, sophisticated equipment and can be quite time-consuming – and the dictates of production pressures that demand, as near as possible, an instant decision, and one usually based on a single number. Here we consider the rheological issues that arise in such a debate, which is aimed at finding what adequate characterisation would require.We will investigate the implications of liquids products being non-Newtonian for two of the most commonly encountered viscometers in factory quality laboratories, i.e. the simple ‘dip-in’ rotating spindle viscometer of the Brookfield type (with its different forms and many imitations) and the more sophisticated concentric-cylinder-type device typified by the Haake Rotovisco VT 550 range. Each is capable of giving a single-number answer for viscosity, but the implications of understanding this single number are different in each case, with the dip-in viscometer being in an infinite sea of liquid and the concentric-cylinder situation being narrow gap. We also investigate when the infinite sea of the ‘dip-in’ viscometer is effectively ‘infinite’ and when is a concentric-cylinder geometry really ‘narrow gap’? We will use the power-law model throughout our discussions.

The use of rotating vane geometries for the measurement of the flow properties of very non-Newtonian liquids has become increasingly popular over the last 20 years. Originally, these geometries were used to measure the apparent yield stresses of inorganic dispersions, but have more recently been used to measure other rheological parameters also. These include the low-strain modulus and the steady-state flow-curves of structured liquids. The particular advantages of the vane geometry are its simplicity of fabrication, ease of cleaning and more than anything else, its elimination of serious wall-slip effects. The development of the vane technique and the theory to go with it, together with its use in various areas are described, where these areas include inorganic colloidal dispersions, foods, bioengineering fermentation broths, etc.

A simple theory is presented to account for the viscometer walls effects encountered when measuring suspensions of large particles (or flocs). The often-recommended minimum ratio of gap-to-particle size ratio of 10:1 is shown to be appropriate for phase volumes up to 25%, but above this value, the ratio needs to be greater. The theory is supported by recent experimental evidence.

This article begins by presenting a study that explored whether the Dyadic Adjustment Scale (DAS) and each of its subscales could discriminate between those therapy couples who would divorce immediately after therapy and those who would not. The DAS was administered to 70 couples during the second session of marital therapy. Results of this study are then reviewed from a clinician’s perspective, and uses of the DAS as an instrument around which effective therapeutic intervention with couples can be structured are suggested. The authors present this article as an example of how clinicians can use research in their therapy, and how clinicians can contribute to the research of couples therapy.

This short article is a summary of a recently published, lengthy review [1] in which the author challenges the often-accepted view that materials have yield stresses, below which no flow takes place. However, following the introduction of the new generation of controlled-stress rheometers it is shown that when careful measurements are made below the supposed ’yield stress‘, flow does actually take place. The argument for the nonexistence of the yield stress as a physical entity now seems insuperable. However, in spite of this, it is nevertheless accepted that an apparent yield stress is a useful mathematical abbreviated description of limited data over a given range of flow conditions. This yield stress parameter can be used effectively for predicting flow, but only within the region of the original measurement that furnished the yield stress.

Process viscometry has many advantages in terms of saving time and gaining more immediate information about a process. However, it can also has disadvantages in terms of compromises that must be made in taking a stream of liquid and passing it through a viscosity-measuring element. The latter operation can be a strong function of flow rate through the instrument, making the measured value variable. The viscometer itself might has been chosen for simplicity of measurement, but which might actually represent a complicated flow pattern in the sense of being a mixture of shear and extensional flow, frequency and acceleration. The best practice in the area of on-line viscometry is reviewed, and the current commercial instruments are compared to this standard. It is concluded that the choice of instrument depends on the pressing need is either for quick information or for reliable information. The Nametre vibrating sphere and the Brookfield concentric-cylinder instruments are highlighted.

The history of commercial viscometry and rheometry over the last thirty years is summarised. In terms of those instruments that have established themselves in a lasting position in the field, we highlight the importance of a sound original idea, good marketing, and constant improvement as technology advances. Instruments in this area fall into three categories: simple, low-cost instruments to measure viscosity or at least an equivalent Newtonian viscosity; multi-speed instruments often able to record data on another display or storage device, and rheometers, i.e. instruments capable of a rotational shearing action, as well as one of the following: oscillation, creep and normal force measurement to give some measure of viscoelasticity. The advances in technology in many areas over the past 30 years have all fuelled the rapid development of instruments that has been nothing short of astonishing. Of especial importance has been the continuous developments of electric motors, and transducers, as well as the increases in speed and memory and reductions in price of digital processors and microprocessors. With this increased computing power perhaps with instruments using complex flow regimes it may be as easy to analyse data as with simple shearing now. There will always be, however, those who want to go to higher frequencies, lower deformations, etc., to meet those challenges of measuring the rheology of materials at the limits.

An account is given of the development of the idea of a yield stress for solids, soft solids and structured liquids from the beginning of this century to the present time. Originally, it was accepted that the yield stress of a solid was essentially the point at which, when the applied stress was increased, the deforming solid first began to show liquid-like behaviour, i.e. continual deformation. In the same way, the yield stress of a structured liquid was originally seen as the point at which, when decreasing the applied stress, solid-like behaviour was first noticed, i.e. no continual deformation. However as time went on, and experimental capabilities increased, it became clear, first for solids and lately for soft solids and structured liquids, that although there is usually a small range of stress over which the mechanical properties change dramatically (an apparent yield stress), these materials nevertheless show slow but continual steady deformation when stressed for a long time below this level, having shown an initial linear elastic response to the applied stress. At the lowest stresses, this creep behaviour for solids, soft solids and structured liquids can be described by a Newtonian-plateau viscosity. As the stress is increased the flow behaviour usually changes into a power-law dependence of steady-state shear rate on shear stress. For structured liquids and soft solids, this behaviour generally gives way to Newtonian behaviour at the highest stresses. For structured liquids this transition from very high (creep) viscosity (>106 Pa.s) to mobile liquid (

The ensuing mechanical response to stressing or straining a structured liquid results in various viscoelastic phenomena, either in the linear region where the microstructure responds linearly with respect to the stress and strain but does not itself change, or in the nonlinear region where the microstructure does change in response to the imposed stresses and strains, but does so reversibly. The complication of thixotropy arises because this reversible, microstructural change itself takes time to come about due to local spatial rearrangement of the components. This frequently found time-response of a microstructure that is itself changing with time makes thixotropic, viscoelastic behaviour one of the greatest challenges facing rheologists today, in terms of its accurate experimental characterisation and its adequate theoretical description. Here a history of thixotropy is given, together with a description of how it is understood today in various parts of the scientific community. Then a mechanistic description of thixotropy is presented, together with a series of applications where thixotropy is important. A list of different examples of thixotropic systems is then given. Finally the various kinds of theories that have been put forward to describe the phenomenon mathematically are listed.

The flow properties of an emulsion are obviously among some of its more important physical attributes in either technical or aesthetic terms. Hence the ability to measure, adjust and, if possible, predict such properties is very important. The linear viscoelastic properties are first discussed, i.e. frequency-dependent storage and loss moduli and the time-dependent creep modulus. Then the non-linear, steady state properties such as shear viscosity and normal stress differences are covered, the latter being measurable with care, but because they are so small, it is concluded that for all practical purposes normal stresses — and thus overt elastic effects like die swell and the Weissenberg effect — are irrelevant for most emulsions. The basic rheology-determining parameters of an emulsion are considered next: continuous phase rheology and the nature of the drops (size distribution, deformability, internal viscosity, concentration and nature of particle—particle interaction). These are best discussed as they change the parameters of the so-called Krieger—Dougherty microstructure/ viscosity equation. In qualitative terms the rheology of emulsions is well understood, i.e. the effects brought about by various formulation and processing variables that result in a change of dispersed phase volume, size distribution and particle—particle interaction as well as particle deformability. What we do not have, however, is a very good quantitative understanding — at least compared with dispersions of solid particles — because of the lack of good model systems ranging from monodispersed to known and controlled degrees of polydispersity, together with an independent change in particle deformability. Until this happens, emulsion rheology will continue to be the study of multifunctional effects with best guesses at effects found. For instance, we shall not be able easily to distinguish between the effects of particle deformation and particle-size-distribution width.

The design of a two-color two-spot laser velocimeter based on an argon laser and using backscattered light is presented. The prism assembly used in splitting the laser's output beam into 514.5- and 488.0-nm beams, also allows for the rotation of the two spots about a common center, allowing two components of a flow to be measured. The system was tested at ranges of 50, 100, and 150 m, and the results of these tests are presented.

This study examined the relationships between parental employment variables, mediating contextual variables, early adolescent's permissive sexual attitudes and behaviors, and gender role traditionalism among 128 rural adolescents. Permissive sexual attitudes were related to permissive sexual behavior, but neither was related to gender role traditionalism. No relationship was found between mothers' employment and adolescents' sexual attitudes and behaviors. Similarly, the sexual attitudes, sexual behaviors, and traditionalism of the adolescents in this sample were not related to the employment variables of their parents, regardless of whether these variables were examined in bivariate or multivariate fashion. Adolescents' ages and perceptions of peer pressure were both positively related to sexual permissiveness, although these relationships appeared to be mediated by general parent-adolescent communication and parentadolescent communication about human sexuality. The only communication variable related to an occupational variable was communication with father, which was positively correlated with fathers' occupational status.

The Defence Evaluation and Research Agency (DERA) has a requirement for an IRPC system to detect surface laid and buried anti-tank landmines in support of Phase 2 of the REmote Minefield Detection System Technology Demonstration Program. Nichols Research Corporation is currently under contact to DERA to design and fabricate the IRPC system for integration in the REMIDS TDP. The IRPC is a Stokes 4-vector IR camera system designed to operate form a static tower, a moving elevated surface platform or a moving airborne platform and will be used to demonstrate the usefulness of passive IR polarimetry for mine and minefield detection. DERA will use the IRPC system to investigate the feasibility of using polarimetric techniques to detect buried and surface laid mines from an airborne platform when operated in conjunction with an ultra wideband SAR.

Consideration is given to the reaction to Barnes and Walters’ 4-page ‘The yield stress myth?’ paper published 21 years ago. It has been cited approximately 180 times since then, as either a standard reference for ‘yield stress’ papers, or to disagree with its sentiment that yield stresses do not actually exist, but are a useful approximation. The references that cite the paper are categorized and commented on.

The problem of mine and minefield detection continues to provide a significant challenge to sensor systems. Although the various sensor technologies (infrared, ground penetrating radar, etc.) may excel in certain situations there does not exist a single sensor technology that can adequately detect mines in all conditions such as time of day, weather, buried or surface laid, etc. A truly robust mine detection system will likely require the fusion of data from multiple sensor technologies. The performance of these systems, however, will ultimately depend on the performance of the individual sensors. Infrared (IR) polarimetry is a new and innovative sensor technology that adds substantial capabilities to the detection of mines. IR polarimetry improves on basic IR imaging by providing improved spatial resolution of the target, an inherent ability to suppress clutter, and the capability for zero (Delta) T imaging. Nichols Research Corporation (Nichols) is currently evaluating the effectiveness of IR polarization for mine detection. This study is partially funded by the U.S. Army Night Vision & Electronic Sensors Directorate (NVESD). The goal of the study is to demonstrate, through phenomenology studies and limited field trials, that IR polarizaton outperforms conventional IR imaging in the mine detection arena.

The Defence Evaluation and Research Agency (DERA) has a requirement for an Infrared Polarimetric Camera (IRPC) system to detect surface laid and buried anti-tank land mines in support of Phase 2 of the Remote Minefield Detection System (REMIDS) Technology Demonstration Programme (TDP). Nichols is currently under contract to DERA to design and fabricate the IRPC system for integration into the REMIDS TDP. The IRPC is a full Stokes vector infrared camera system designed to operate from a static tower, a moving elevated surface platform, or a moving airborne platform and will be used to demonstrate the usefulness of passive IR polarimetry for mine and minefield detection. DERA will use the IRPC system to investigate the feasibility of using polarimetric techniques to detect buried and surface laid mines from an airborne platform when operated in conjunction with an ultra wide band synthetic aperture radar (UWB SAR). This paper describes the IRPC system, which is currently being developed for delivery to DERA in April 1999.

Originally, it was accepted that the yield stress of a solid was essentially the point at which, when the applied stress was increased, the deforming solid first began to show liquid-like behaviour, i. e. continual deformation. In the same way, the yield stress of a structured liquid was originally seen as the point at which, when decreasing the applied stress, solid-like behaviour was first noticed, i. e. no continual deformation. However as time went on, and experimental capabilities increased, it became clear, first for solids and lately for soft solids and structured liquids, that although there is usually a small range of stress over which the mechanical properties change dramatically (an apparent yield stress), these materials nevertheless show slow but continual steady deformation when stressed for a long time below this level, having shown an initial linear elastic response to the applied stress.

Two Triband Imaging Infrared Radiometers (TI 2 R) were designed and fabricated for the U.S. Army Strategic Defense Command by Automated Sciences Group, Inc. The first TI 2 R system was designed to perform hardware-in-the-loop (HWIL) simulations using a laser scene projector and electronic signal injection. The second TI 2 R system was designed for field testing to provide validation data for the HWIL simulation. This paper describes the design and operation of these two systems and the HWIL testing that was performed.

(1997). Massachusetts Congregationalist Political Thought, 1760–1790: The Design of Heaven. History: Reviews of New Books: Vol. 25, No. 2, pp. 61-62.

(1995). Congregational Communion: Clerical Friendship in the Anglo-American Puritan Community, 1610–1692. History: Reviews of New Books: Vol. 23, No. 3, pp. 104-105.

The ability to detect ice on airplanes or roadways and land mines in fields of rubble would save many lives. Imaging polarimetry provides one basis for such detection methods. These and other applications are discussed in this article.