bluuebunny/crossref_metadata_2025 huggingface dataset:
A Cutting-Date Estimation Technique for Ponderosa Pine and Douglas Fir Wood Specimens
Authors: Nash Stephen E.
Published: April 2006

The interpretation of noncutting tree-ring dates from archaeological sites often proves problematic, and many sites in the Southwest may be more securely dated if cutting dates can be reliably estimated. Analysis of 54 ponderosa pine and 46 Douglas fir specimens reveals that the relationship between heartwood and sapwood in these species is sufficiently structured that regression analysis can be used to estimate the number of sapwood rings, and by extension the tree's cutting date, on the basis of the number of heartwood rings present on wood specimens. The efficacy of this estimation technique is evaluated on samples from localized and well-dated proveniences at Walpi Pueblo, as well as in light of the aggregate date distribution curve for that site. Results suggest that uncritical acceptance of estimated cutting dates is ill advised, but that when cutting-date estimates (and their associated confidence intervals) are considered in light of contextualizing architectural and archaeological data, they may suggest alternative room construction and repair hypotheses. When considered as part of the aggregate date distribution for a site, estimated cutting dates may identify and augment date concentrations, thereby helping secure the chronometric placement of prehistoric sites in the Southwest.
Early Pottery in the Amazon: A Correction
Authors: Williams Denis
Published: April 2006

Based on submission forms and other documents deposited in the Smithsonian Institution archives on termination of the Smithsonian Radiocarbon Dating Laboratory in 1986, Anna Roosevelt argues that shell middens on the coast of Guyana and northeastern Brazil contain pottery, and that the dates support her argument that “Amazonian early pottery is the most securely dated early pottery in the New World” (1995:128). Pending publication of a detailed monograph, I maintain that the Guyana sites in question are preceramic and thus offer no support to Roosevelt's thesis.
Mental Tests in the Study of the African
Authors: Oliver Richard A. C.
Published: April 2006

The phrase ‘the mentality of the native’ is much on the lips of those whose work brings them into contact with Africans. The need for the study of African mentality is widely recognized; and an immense body of knowledge has accrued from the labours of administrators, missionaries, anthropologists, and others. Yet those whose knowledge is deepest are the first to admit that we still know only in part and darkly. Now it may be that, to achieve a fuller and clearer knowledge of the African mind, not only more study but additional methods of study are required. The main method up till now has necessarily been observation—observation of the behaviour of Africans in natural, everyday situations; and the result of this method has been the description of such behaviour. To this method we owe almost all of our present knowledge of the mentality of the African; and it seems likely that this must for long remain the chief source of our knowledge. It is not, however, the ideal scientific method. Our knowledge could probably be extended and made in some ways more precise by the method of studying the behaviour of Africans not in natural, everyday situations but in situations experimentally arranged and controlled. This method would result not merely in description but in measurement. Results obtained in controlled situations and expressed in quantitative terms would be results precise and verifiable. This method of study is not to be adopted prematurely, before the conditions of its technique can be fulfilled. But the advance of scientific understanding will sooner or later demand some such scientific method. One such method which is already being experimented with does involve the observation of the behaviour of Africans in controlled situations and does yield quantitative results. This is the method of mental testing.
The Gold Coast, 1931
Authors: Harman H. A.
Published: April 2006

Under this title Mr. A. W. Cardinall has prepared a review of conditions in the Gold Coast in 1931 as compared with those of 1921, using figures and facts collected by him as Chief Census Officer, and adding an historical, ethnographical, and sociological survey of the people of that country. Accompanying the review is a volume of appendices containing comparative returns and general statistics of the 1931 census. Both books are printed by the Government Printer, Accra, and are obtainable through the Crown Agents for the Colonies.
Les Prépréfixes dans les Langues Bantoues du Nord-Ouest du Congo Belge
Authors: de Boeck L. B.
Published: April 2006

Opening Paragraph

Une particularité des langues bantoues, dont on ne connaît encore ni l'origine, ni toute l'étendue, est l'emploi de prépréfixes devant les substantifs. On donne le nom de prépréfixes à des éléments qui précèdent les préfixes nominaux ordinaires; cette particularité a été constatée dans assez bien de langues bantoues, tant dans le sud — par exemple, Zulu, Xhosa, Thonga — que dans le nord-est — Ziba, Ruanda, Ganda — de l'Afrique.
Morse v. Reid: The First Reported Federal Copyright Case
Authors: Gordan John D.
Published: April 2006

Scholarly treatments of the history of early federal copyright litigation have overlooked what may be the earliest and must certainly be the most interesting decision of the period—Morse v. Reid, decided in the United States Circuit Court for the District of New York on April 4 and 6, 1798. Absent its identification in Wilfred J. Ritz's invaluable American Judicial Proceedings First Printed Before 1801, Morse v. Reid would probably remain unknown.
The Economic and Cultural Impact of the Origins of Property: 1180-1220
Authors: Palmer Robert C.
Published: April 2006

The development of property in England between 1176 and 1220 was the result of a complicated interaction between social mores made law and bureaucratic action. In the Assize of Northampton, Henry II undertook regular supervision of proprietary decisions to prevent his men from preparing a rebellion like that of 1173-74. The supervision assumed peacetime feudal norms, but in the hands of bureaucratic justices even prior to 1200 this supervision increasingly restricted lords' power to discipline their tenants, at a time when disciplinary power was far more important than proprietary decisions. By 1220, the relative importance of proprietary matters and disciplinary power had been reversed. But proprietary action by the lord was so attenuated that seisin—lawful possession—was possible now even without lordly acceptance. Such insulation of the tenant from his lord was a bond established between the tenant and his tenement: property.
Massachusetts and the Judges: Judicial Independence in Perspective
Authors: Black Barbara Aronstein
Published: April 2006

This is an essay about an incident that took place in the Province of Massachusetts Bay during the period 1772–1774, an incident that I will call the Affair of the Royal Salary. Close relative of the Stamp Act Crisis, The Boston Tea Party, even the Boston Massacre, the Affair of the Royal Salary similarly involved a clash between the forces of popular government and those of imperial government; like its better known cousins it is part of the story of the coming of the American Revolution in Massachusetts. In addition, since the Salary around which the Affair developed was intended for judges, the Affair of the Royal Salary is part of the history of judicial independence in Massachusetts.
Law in a Reign of Terror
Authors: Watson Alan
Published: April 2006

From David Daube I learned Roman law and many other things: inter alia that accepted doctrines and approaches need continual re-examination, that research in one field may illumine another, that limitations because of one's background or upbringing, or in one's academic skills affect one's judgment, and that the connection between life and law is more complex than is usually supposed. A paper dedicated to a beloved and revered master may properly strike a more personal—though not less scholarly—note than is usual; especially when the theme concerns tyranny and the recipient has experienced tyranny and withstood it mightily.
The Use of Manorial Court Rolls in Demographic Analysis: A Reconsideration
Authors: Razi Zvi
Published: April 2006

Drs. L.R. Poos and R.M. Smith have strongly criticized the uses made of manorial court rolls for demographic analysis. They have argued that the data obtained from the court records are inadequate in measuring the demographic trend and in making observations about replacement rates, expectation of life, marriage and illegitimacy. It seems to me, however, that although their criticism is partly justified, on the whole it is unduly negative. First, the claim that the demographic trend cannot be measured from court rolls will be examined; and thereafter the other issues raised by Poos and Smith will be discussed.
The Struggle for Judicial Independence in Antebellum North Carolina: The Story of Two Judges
Authors: Pratt Walter F.
Published: April 2006

The Supreme Court of North Carolina is an anomaly among state courts in the antebellum years. In a period dominated by democratic reforms of state government, the court did not merely survive unscathed it actually increased its independence. The remarkable success of this court is largely attributable to the personal reputations and political acumen of two of its judges, Thomas Ruffin and William Gaston. Without those two men it is likely that the Supreme Court would have been abolished in a wave of democratic reforms that peaked in North Carolina with the constitutional amendments of 1835.
Summary Justice and Working-Class Marriage in England, 1870–1940
Authors: Behlmer George
Published: April 2006

England's criminal justice system has been depicted as evolving from a preindustrial form in which wide judicial discretion served to legitimate the social order, to a new form where the need to impose industrial discipline on an increasingly urbanized work force produced less harsh but more systematic punishments. According to this vision, the wheels of Victorian justice ground both more gently and more intrusively than they had a century before, since along with the abolition of many capital crimes and the diminishing resort to incarceration went an intensified examination of private lives. As Jennifer Davis has made clear, however, historians of crime often underestimate the degree of continuity between eighteenth- and nineteenth-century law enforcement, particularly at the local level. Significantly, both eighteenth-century justices of the peace and nineteenth-century police court magistrates enjoyed great latitude in their dealings with the poor people who appeared before them. Nowhere is the highly personal and unsystematic nature of modern summary justice more strikingly revealed than in the police court's adjudication of disputes between husbands and wives.
The Daughters of Job: Property Rights and Women's Lives in Mid-Nineteenth-Century Massachusetts
Authors: Avery Dianne , Konefsky Alfred S.
Published: April 2006

Sometime in the winter of 1839, Keziah Kendall, a thirty-two-year-old woman living with her two sisters on a dairy farm “not many miles from Cambridge,” heard from her “milkman” that a public lecture would be delivered on the legal rights of women. Kendall “thought [she] would go and learn,” but when she attended she found that she “did not like that lecture much.” The speaker was Simon Greenleaf, Royall Professor of Law at Harvard University, who at the time was delivering lyceum lectures in eastern Massachusetts on the subject of women's rights. Not the least bit intimidated by Greenleaf's stature, Kendall wrote him a candid letter, expressing her disapproval of his talk: “[T]here was nothing in it but what every body knows. … What I wanted to know, was good reasons” for the rules governing the legal rights of women “that I cant account for. I do hope if you are ever to lecture at the Lyceum again, that you will give us some.” Kendall then proceeded to tell Professor Greenleaf the remarkable and poignant story of how her personal experiences had shaped her interest in her own legal rights.
A Pacific Rim: Crime and Punishment in Santa Clara County, 1922
Authors: Friedman Lawrence M. , Tabor Paul
Published: April 2006

The history of American criminal justice is, to say the least, by no means an overplowed field. In fact, it has gotten systematic attention only in recent years. The public, of course, is fascinated with crime and horrified by crime; stories about crime and criminal justice cry out from the pages of newspapers and dominate movies and television. Historical research is another matter.

The first half of the twentieth century should be a rich field for research. Records are available in abundance and in every county. Moreover, there are, particularly for the 1920s and 1930s, a fair number of state crime surveys and other empirical studies of criminal justice. California and the West, however, have been somewhat neglected. This article presents some data on one county, Santa Clara County, in one year, 1922, as a modest beginning.
The Constitution in the Glass Case and Constitutions in Action
Authors: Hulsebosch Daniel J.
Published: April 2006

Bruce Mann's irreverent schoolmate would have made a good historian. Unlike the hapless docent, the student (whatever his intent) grasped that a word's various meanings, now divided, might once have been united. The word constitution, for example, was born in obfuscation—and this ambiguity enabled it to become a powerful analytical tool in the early modern period. In fact, the political meaning of constitution derived from the word's physiological connotation, which is why the latter appears first in Professor Mann's dictionary.
Gun Laws in Early America: The Regulation of Firearms Ownership, 1607–1794
Authors: Bellesiles Michael A.
Published: April 2006

King James I stated the official position of the English governing elite on gun ownership succinctly. When it was suggested that more of England's subjects should enjoy the right to hunt and own firearms, James responded that “it is not fit that clowns should have these sports.”

Discussion of early American gun laws begins with consideration of the English legal heritage. In the last few years, adherents of the self-described “standard model” of the meaning of the Second Amendment have constructed a paradigm of an uninterrupted tradition of legally sanctioned individual gun ownership in America. Such a construction starts with the idea that the British brought an acceptance of the universal ownership of firearms with them to the Americas. That cultural norm gave form to the meaning of the Second Amendment, which institutionalized an individual right to bear arms for purposes of personal and communal defense and as a security against a tyrannical government. This history matters greatly to these scholars in establishing an original intent in the Second Amendment to protect an individual's right to own guns.
When Christianity Was Part of the Common Law
Authors: Banner Stuart
Published: April 2006

Nineteenth-century American judges and lawyers often claimed that Christianity was part of the common law. From Kent and Story in the early part of the century, to Cooley and Tiedeman toward the end, the maxim that “Christianity is part and parcel of the common law” (or some variant thereof) was heard so often that later commentators could refer to it as a matter “decided over and over again,” one which “[t]ext writers have reiterated and courts have affirmed.” The maxim even received an endorsement of sorts from the Supreme Court, which in 1844 affirmed that “the Christian religion is part of the common law of Pennsylvania.”
Judges v. Jurors: Courtroom Tensions in Murder Trials and the Law of Criminal Responsibility in Nineteenth-Century England
Authors: Wiener Martin J.
Published: April 2006

Although it is well known that the criminal law's administration in nineteenth-century England altered decisively, little important change has been noted in the substantive criminal law. Yet change there was, but produced less through legislation (as was much administrative change) or even appeals court rulings than through everyday criminal justice practice. In particular, the effective meanings of legal terms central to the prosecution of homicide—terms such as provocation, intention, and insanity—were in motion during the nineteenth century as part of a broader redefining and reimagining of liability and responsibility. To grasp these often subtle shifts of meaning, we must look to the sites in which they occurred, the most important of which were the courtrooms of the assize courts, where the most serious offenses were tried.
Biological Neuronal Networks, Modeling of
Authors: Giugliano M. , Arsiero M.
Published: April 2006

In the central nervous system, neurons interact by brief electrical pulses called action potentials or spikes, and they influence each other by the synaptic release of neuro‐transmitter molecules after each spike. The electrical distributed activity, developing in populations of synaptically connected neurons, is considered the cellular correlate of perception, sensory integration, motor‐control, as well as many other behaviorally relevant phenomena. For such a reason, the quantitative understanding of the principles underlying the electrophysiological collective activity that emerges in a network constitutes a fundamental issue of the neurosciences and neuroengineering. In this chapter, we introduce the reader to the mathematical modeling of the electrophysiology of a population of biological neurons. We thus consider a subject that is different from theartificialneural networks, widely employed in a variety of industrial and scientific applications, and unrelated to neurobiology although originally inspired by it. By describing, in detail, two models of single‐neuron electrical excitability, and introducing a realistic biophysical model of synaptic interactions, we discuss the approach for studying the nervous system at the microcircuit and network levels. We finally present the results of computer simulations of excitatory networks, where emergent properties characterize the collective dynamics. By further including short‐term homosynaptic plasticities in the model of synaptic transmission, as recently suggested by evidences at the central synapse, we show that additional computational properties may emerge, such as the processing of motion direction selectivity and the discrimination of transients in the afferent inputs.
Synthesis of Glycaro‐1,5‐lactams and Tetrahydrotetrazolopyridine‐5‐carboxylates: Inhibitors of β‐D‐Glucuronidase and α‐L‐Iduronidase
Authors: Pabba Jagadish , Rempel Brian P. , Withers Stephen G. , Vasella Andrea
Published: April 2006

The known glucaro‐1,5‐lactam 8, its diastereoisomers 9–11, and the tetrahydrotetrazolopyridine‐5‐carboxylates 12–14 were synthesised as potential inhibitors of β‐D‐glucuronidases and α‐L‐iduronidases. The known 2,3‐di‐O‐benzyl‐4,6‐O‐benzylidene‐D‐galactose (16) was transformed into the D‐galactaro‐ and L‐altraro‐1,5‐lactams 9 and 11 via the galactono‐1,5‐lactam 21 in twelve steps and in an overall yield of 13 and 2%, respectively. A divergent strategy, starting from the known tartaric anhydride 41, led to the D‐glucaro‐1,5‐lactam 8, D‐galactaro‐1,5‐lactam 9, L‐idaro‐1,5‐lactam 10, and L‐altraro‐1,5‐lactam 11 in ten steps and in an overall yield of 4–20%. The anhydride 41 was transformed into the L‐threuronate 46. Olefination of 46 to the (E)‐ or (Z)‐alkene 47 or 48 followed by reagent‐ or substrate‐controlled dihydroxylation, lactonisation, azidation, reduction, and deprotection led to the lactams 8–11. The tetrazoles 12–14 were prepared in an overall yield of 61–81% from the lactams 54, 28, and 67, respectively, by treatment with Tf2O and NaN3, followed by saponification, esterification, and hydrogenolysis. The lactams 8–11 and 40 and the tetrazoles 12–14 are medium‐to‐strong inhibitors of β‐D‐glucuronidase from bovine liver. Only the L‐ido‐configured lactam 10 (Ki = 94 μM) and the tetrazole 14 (Ki = 1.3 mM) inhibit human α‐L‐iduronidase.
Clinical outcome in patients with bipolar I disorder, obsessive compulsive disorder or both
Authors: Centorrino Franca , Hennen John , Mallya Gopinath , Egli Samy , Clark Tim , Baldessarini Ross J.
Published: April 2006

Background

Bipolar disorder (BPD) is often comorbid with obsessive‐compulsive (OCD) and other anxiety disorders, but the impact of such comorbidity on long‐term outcome has not been evaluated systematically.

Methods

Extensive follow‐up assessments were carried out at 4.3 years after index hospitalizations in a mixed BPD‐OCD group (N = 20) compared to matched groups with BPD (N = 22) or OCD (N = 20) alone.

Results

At follow‐up, ratings of functional status were similar across groups. Rehospitalizations were similar among BPD‐OCD and BPD subjects, but 2.9‐times more frequent among comorbid than OCD patients. OCD symptoms averaged 150% more severe in OCD than comorbid subjects, and were not measured in BPD subjects.

Conclusions

Despite potential sampling bias with previously hospitalized subjects, the findings suggest that comorbid BPD‐OCD patients may be clinically more similar to BPD than OCD patients, and that BPD‐OCD comorbidity may not negatively impact the long‐term clinical outcome. Copyright © 2006 John Wiley & Sons, Ltd.
The role of mass spectrometry in the study of non‐enzymatic protein glycation in diabetes: An update
Authors: Lapolla Annunziata , Fedele Domenico , Seraglia Roberta , Traldi Pietro
Published: April 2006

Recent studies on non‐enzymatic protein glycation are reviewed, and results are critically discussed. Advanced glycation end products (AGE) levels in the body reflect a balance between their formation and catabolism. AGE proteolysis leads to the formation of low‐molecular‐weight AGE (AGE peptides) that are normally excreted in urine. In the case of diabetic disease and/or renal failure, AGE peptides accumulate in plasma. Because of their high reactivity, these compounds have been thought to play a role in the progression of chronic complications. The structural identification of these compounds is particularly important, and a strategy has been designed for their possible definition. A series of experiments has been devoted to the study of the enzymatic degradation products of in vitro glycated human serum albumin (HSA). This approach, based on different MS methods (LC/ESI/MS, LC/ESI/FTMS, MALDI), led to the detection of the glycated peptides generated by digestion of HSA. A further study was devoted to the possible identification of the peptides identified in the glycated HSA digestion products in the plasma of diabetic and nephropatic subjects. No glycated HSA digestion products were found in plasma samples of the subjects under investigation even if clear differences were found among the LC runs from populations of healthy, diabetic, and nephropatic subjects. Parallel investigations were devoted to the evaluation of glyoxal and methylglyoxal‐dicarbonyl compounds that originate at the intermediate stage of the Maillard reaction. This evaluation was performed in diabetic patients, before and after the achievement of good metabolic control, and in nephropatic patients subjected to peritoneal dialysis (PD). In the latter case, results indicated that these dicarbonyl compounds, already present in the dialysis fluids, show a decrease in plasma and in dialysis fluids; those data suggested their reaction at peritoneal membrane level. © 2006 Wiley Periodicals, Inc.
Characterization of antimicrobial films containing basil extracts
Authors: Suppakul Panuwat , Miltz Joseph , Sonneveld Kees , Bigger Stephen W.
Published: April 2006

The properties of low‐density polyethylene (LDPE)‐based films containing either linalool or methylchavicol as antimicrobial (AM) additives were evaluated. Slight decreases in transparency, water vapour and oxygen transmission rates were found in the extruded films containing 0.34% w/w linalool or methylchavicol. The infrared (IR) spectra of the AM films were similar to that of additive‐free LDPE film. However, carbonyl peaks could also be observed in the spectra of the AM films. There was no significant difference in the degree of crystallinity and the melting temperature range of the different films. Derivative thermogravimetry mass‐loss curves showed that the thermal decomposition temperatures of the AM films were marginally lower than that of LDPE film. Electron micrographs indicated that AM LDPE‐based films exhibited no evidence of changes in microstructure to suggest that linalool and methylchavicol were not evenly distributed in the film. Copyright © 2006 John Wiley & Sons, Ltd.
THE MYSTERY OF OLD BAILEY COUNSEL
Authors: Gallanis T.P.
Published: April 2006

This article proffers a hypothesis about a persistent historical mystery: Why did the use of defence lawyers in felony trials at the Old Bailey increase so noticeably in the last quarter of the eighteenth century?
Fahrenheit 9/11: The Temperature Where Morality Burns
Authors: WEBER CYNTHIA
Published: April 2006

Michael Moore's 2004 film Fahrenheit 9/11 is a visual and narrative tour de force that critiques everything from the controversial conditions under which George W. Bush assumed the US presidency to President Bush's handling of his so-called “war on terror.” With its tagline “The temperature where freedom burns,” Moore stresses the dubious ethical nature of the Bush administration's post-9/11 policies, especially as they redefine the US relationship between freedom and censorship. In so doing, he challenges the Bush administration's constructions of US morality as ultimately elitist and self-serving, substituting his own populist, class-based moral America(n) in its place.
Of Nonlimited Locality/Identity: Chinese Diaspora Poetry in America
Authors: ZHANG BENZI
Published: April 2006

What we need, it seems to me, is a global sense of local, a global sense of place.
Flow in heated curved pipes
Authors: Yao Lun-Shin , Berger Stanley A.
Published: April 2006

The fully developed laminar flow in a heated curved pipe under the influence of both centrifugal and buoyancy forces is studied analytically. The pipe is assumed to be heated so as to maintain a constant axial temperature gradient. Both horizontal and vertical pipes are considered. Solutions for these two cases are obtained by regular perturbations in the Dean number and the product of the Reynolds and Rayleigh numbers; the solutions are therefore limited to small values of these parameters. Predictions of the axial and secondary flow velocities, streamlines, shear stress, temperature distribution and heat transfer are given for a representative case.
Coherent structures in the outer mixing region of annular jets
Authors: Chan W. T. , Ko N. W. M.
Published: April 2006

This paper describes in detail the overall pressure and spectral results in the outer mixing region of three annular jets. The outer mixing region can be considered as the result of the shearing of a single jet by the ambient air. The coherent structures found consist of an array of toroidal jet vortices convecting downstream in the outer mixing region. The structures tend to agree with the ones for a single jet.
On Rayleigh's criterion for slowly varying flows
Authors: Seminara Giovanni
Published: April 2006

The inviscid centrifugal instability of slowly varying flows is shown to be asymptotically associated with the lowest-order spatial dependence of the basic flow satisfying Rayleigh's criterion. This result requires special attention for basic flows which reverse their direction. At the instant of reversal the growth rate of the disturbance bifurcates and the choice of the proper branch requires that viscous effects be taken into account within a conveniently small neighbourhood of the branch point. Previous results by Rosenblat (1968) are shown to be incorrect. Such results were based on overlooking the need for viscous effects to be accounted for within a neighbourhood of the bifurcation point. This led to a wrong choice of the path to be followed at bifurcation.
On the shape of a deformed eddy with varying Coriolis force
Authors: Salusti E.
Published: April 2006

We present a simple model of a steady barotropic eddy superimposed on a current, with varying Coriolis force, to study the structure of a nonlinear deformed eddy. We also develop the linearized time-dependent formulation of the problem. The resulting solutions are stable perturbations, with scales smaller than the eddy.
Turbulent flow and heat transfer in pipes with buoyancy effects
Authors: Abdelmeguid A. M. , Spalding D. B.
Published: April 2006

A finite-difference procedure, is employed to predict the turbulent flow and heat transfer in horizontal, inclined and vertical pipes when influenced by buoyancy. The flow is treated as parabolic; and the turbulence model used involves the solution of two differential equations, one for the kinetic energy of turbulence and the other for its dissipation rate. Results are presented for the velocity and temperature fields, and the associated flow-resistance and heat-transfer coefficients. The predictions for horizontal and vertical pipes have been compared with the available experimental results, and the agreement obtained is good.
A simple model of the mutual interaction of parallel flow and cellular motion in a shear layer applied to the finite amplitude instability of plane Couette flow
Authors: Steppeler J.
Published: April 2006

The disturbing motion of plane Couette and Poiseuille flow is described using three parameters: two amplitudes corresponding to the disturbance of the parallel flow and the cellular motion, respectively, and the angle ϕ0 which defines the orientation of the vortex blobs with respect to the parallel flow. Equations of motion for these parameters are obtained using a Ritz-Galerkin method. For Reynolds numbers above a critical value sufficiently big disturbances will grow until a steady finite amplitude state is achieved. The energy of the disturbance remains finite, in spite of the highly truncated field representation using only three parameters. This is possible because of the nonlinear dependence of the field functions on ϕ0. The critical values of Reynolds number, above which finite amplitude states exist, are computed for the plane Couette flow and the Poiseuille channel flow.
Large-scale coherent structures in the wake of axisymmetric bodies
Authors: Fuchs H. V. , Mercker E. , Michel U.
Published: April 2006

The unsteady flow past a circular disk is studied with hot-wire and microphone probes positioned in planes normal to the axis of symmetry at 3 and 9 disk diameters down-stream. Both the fluctuating velocity and pressure signals are shown to be continuously dominated by large-scale coherent motions enveloping the wake flow as a whole. This suggests narrowband two-point space correlations as an experimental tool for describing spatial coherence and phase characteristics of the basically random signals. The specific symmetry imposed by the axisymmetric boundary conditions of the disk enables a decomposition of the large-scale flow phenomena into relatively simple elementary structures or modes. The resulting azimuthal constituents are quantified in terms of their respective magnitudes and individual power spectra.

The capability of the approach to uncover characteristic features of turbulence as far as its large-scale domain is concerned is demonstrated by a comparison of the present results with certain remarkably different features found in earlier jet flow investigations: the m = 1 and m = 2 modes are found to clearly dominate in wakes whereas the m = 0 and m = 1 modes were dominant in jets in a relevant range of Strouhal numbers. These large-scale coherent structures are more than just an interesting flow phenomenon; they must have a tremendou back-reaction on rigid flow boundaries (particularly if these allow a vibrational response) and may give rise to specific feedback mechanisms.

The analysing technique proposed for studying large-scale flow phenomena injets and wakes removes part of the randomness in the turbulent signals without artificially exciting or forcing them in one way or another. No conditional sampling of the naturally occurring fluctuations is required, either. The method may be applicable to other than strictly axisymmetric flow configurations, too.
Radiative interactions in boundary layers
Authors: Venkateshan S. P. , Prasad K. Krishna
Published: April 2006

A detailed description of radiative interactions in laminar compressible boundary layers for moderate Mach numbers is presented by way of asymptotic analysis and supporting solutions. The radiation field is described by the differential approximation. While the asymptotic analysis is valid for largeN(the ratio of photon mean free path to molecular mean free path) and arbitrary Boltzmann number,Bo(the ratio of convective heat flux to radiation heat flux), the solutions are obtained forBo[Lt ] 1, the case of strong radiative interactions.

The asymptotic analysis shows the existence of an optically thin boundary layer for largeNand allBo.ForBo[Lt ] 1, two outer regions are observed — one optically thin (at short distances from the leading edge) and the other optically thick (at large distances from the leading edge). An interesting feature not pointed out in the previous literature is the existence of a wall layer at large distances from the leading edge where convective heat flux can be ignored to the leading order of approximation. The radiation field in all cases can be very well approximated by a one-dimensional description.

The solutions have been constructed using the ideas of matched asymptotic expansions by approximate analytical procedures and numerical methods. It is shown that, to the leading order of approximation, the radiation slip method yields exactly the same result as the more complicated matching procedure. Both the cases of linear and nonlinear radiation have been considered, the former being of interest in developing approximate methods which are subsequently generalized to handle the nonlinear problem. Detailed results are presented for both cases.
A ‘turbulent spot’ in an axisymmetric free shear layer. Part 1
Authors: Sokolov M. , Hussain A. K. M. F. , Kleis S. J. , Husain Z. D.
Published: April 2006

A three-dimensional ‘turbulent spot’ has been induced in the axisymmetric free mixing layer of a 12.7 cm diameter air jet by a spark generated at the nozzle boundary layer upstream of the exit. The spot coherent-structure signature, buried in the large-amplitude random fluctuating signal, has been educed at three downstream stations within the apparent self-preserving region of the mixing layer (i.e. x/D = 1.5, 3.0 and 4.5) at the jet exit speed of 20 ms−1. The eduction has been performed through digital phase averaging of the spot signature from 200 realizations. In order to reduce the effect of the turbulence-induced jitter on the phase average, individual filtered signal arrays were optimally time-aligned through an iterative process of cross-correlation of each realization with the ensemble average. Further signal enhancement was achieved through rejection of realizations requiring excessive time shifts for alignment. The number of iterations required and the fraction of realizations rejected progressively increase with the downstream distance and the radial position.

The mixing-layer spot is a large-scale elongated structure spanning the entire width of the layer but does not appear to exhibit a self-similar shape. The dynamics of the mixing-layer spot and its eduction are more complicated than those of the boundary-layer spot. The spot initially moves downstream essentially at a uniform speed across the mixing layer, but further downstream it accelerates on the high-speed side and decelerates on the low-speed side. This paper discusses the data acquisition and processing techniques and the results based on the streamwise velocity signals. Phase average distributions of vorticity, pseudo-streamlines, coherent and background Reynolds stresses and further dynamics of the spot are presented in part 2 (Hussain, Kleis & Sokolov 1980).
Bouyancy-driven asymmetric water boundary layer along a heated cylinder
Authors: Yao Lun-Shin , Catton Ivan , Mcdonough J. M.
Published: April 2006

The development of a three-dimensional water boundary layer along a heated longitudinal horizontal cylinder is studied by a finite-difference method. The secondary flow is induced in an otherwise axially symmetric laminar boundary layer by the buoyancy force. The development of the boundary layer is studied under two heating conditions: constant wall heat flux and constant wall temperature. In general, close to the leading edge, the magnitude of the secondary flow is small and the boundary-layer flow is forced-convection dominant. The secondary flow grows downstream, and the interaction of the free and forced convection becomes important. The flow becomes free-convection dominant further downstream. The temperature-dependent viscosity of water has the effect of thinning the heated boundary layer. The buoyancy effect and the variable viscosity effect enhance each other over the lower part of the cylinder and compete with each other over the upper part of the cylinder. The numerical results compare with the forced convection dominant asymptotic solution and indicate that the asymptotic solution is only valid when x < 0·1a/ε½. Since the boundary layer is thin compared with the radius of the cylinder, the transverse curvature effect is small and can be neglected. Therefore, the solution can be applied to the entrance region of heated straight pipes as the zeroth-order boundary-layer flow.
A quasi-linear theory for rotating flow over topography. Part 1. Steady β-plane channel
Authors: Davey Michael K.
Published: April 2006

Steady rotating flow over topography in a periodic channel is examined, with emphasis on the interaction of waves, topography and mean flow. A simple quasi-linear theory is presented that features an implicit equation relating the net zonal flow to the forcing and topography. A good description of the dynamics is obtained, even when resonant Rossby waves appear. Multiple solutions for given external parameters are predicted in some cases, and confirmed by comparison with a fully nonlinear numerical model.

The nonlinear results also indicate that the zonally averaged shear can be important when topographic effects or Rossby numbers are large. With this factor taken into account the theory gives good agreement with the fully nonlinear model, as long as eddy–eddy interactions are minor.

The theory is relevant to the dynamics of planetary waves in the atmosphere, and may also be applied to some oceanic problems.
The extensional viscosity of a dilute suspension of spherical particles at intermediate microscale Reynolds numbers
Authors: Ryskin G. , Ryskin G. , Rallison J. M.
Published: April 2006

The extensional viscosity of a dilute suspension of spherical particles (rigid spheres, viscous drops or gas bubbles) is computed for the case when the Reynolds number of the microscale disturbance motionRis not restricted to be small, as in the classical analysis of Einstein and Taylor. However, the present theory is restricted to steady axisymmetric pure straining flow (uniaxial extension). The rate of energy dissipation is expressed using the Bobyleff-Forsythe formula and then conditionally convergent integrals are removed explicitly. The problem is thereby reduced to a determination of the flow around a particle, subject to pure straining at infinity, followed (for rigid particles) by an evaluation of the volume integral of the vorticity squared. In the case of fluid particles, further integrals over the volume and surface of the particle are required. In the present paper, results are obtained numerically for 1 [les ]R[les ] 1000 for a rigid sphere, for a drop whose viscosity is equal to the viscosity of the ambient fluid, and for an inviscid drop (gas bubble). For the last case, limiting results are also obtained forR→ ∞ using Levich's approach.

All of these results show a strain-thickening behaviour which increases with the viscosity of the particle. The possibility of experimental verification of the results, which is complicated by the inapplicability of the approximation of material frame-indifference in this case, is discussed.
Centrifugal instabilities in finite containers: a periodic model
Authors: Hall P.
Published: April 2006

A simplified model problem has recently been suggested by Schaeffer (1980) in order to explain the results obtained by Benjamin (1978) in his investigation of Taylor vortices in short cylinders. In particular Schaeffer reproduces the results obtained by Benjamin for cylinders so short that only two-cell or four-cell flows are possible. The model given by Schaeffer has artificial conditions imposed on the fluid velocity field at the end walls. These conditions depend on a parameter α and reduce to the no-slip condition when α = 1. If α = 0 the conditions require that the normal component of the velocity and the normal derivative of the tangential velocity vanish at the ends. In this case the onset of Taylor vortex-like motion occurs as a bifurcation from purely circumferential flow. If α is now taken to be small and positive, there is no bifurcation and the circulatory flow develops smoothly. We shall use perturbations method for the case of small α. The imperfect bifurcation problem which we obtain predicts some results consistent with those of Benjamin.
Incompressible flow in a labyrinth seal
Authors: Stoff H.
Published: April 2006

The incompressible flow in a labyrinth seal is computed using the ‘κ−ε’ turbulence model with a pressure-velocity computer code in order to explain leakage phenomena against the mean pressure gradient. The flow is axisymmetric between a rotating shaft and an enclosing cylinder at rest. The main stream in circumferential direction induces a secondary mean flow vortex pattern inside annular cavities on the surface of the shaft. The domain of interest is one such cavity of an enlarged model of a labyrinth seal, where the finite difference result of a computer program is compared with measurements obtained by a back-scattering laser-Doppler anemometer at a cavity Reynolds number of ∼ 3 × 104and a Taylor number of ∼ 1·2 × 104. The turbulent kinetic energy and the turbulence dissipation rate are verified experimentally for a comparison with the result of the turbulence model.
The nonlinear capillary instability of a liquid jet. Part 3. Experiments on satellite drop formation and control
Authors: Chaudhary K. C. , Maxworthy T.
Published: April 2006

We continue the experiments of Chaudhary & Maxworthy (1980) to include the behaviour at and beyond the point along the jet at which individual drops interspersed with small satellite drops begin to form. In particular, we show how the perturbation wavenumber and amplitude for a fundamental disturbance alone combine to give a variety of modes of breakup into drops and a variety of patterns of drop recombination further downstream. We then show how the addition of a third harmonic to this fundamental can be used in a variety of parameter combinations to control the behaviour of the satellite drops and in some cases eliminate them completely.
Projected changes in the Caspian Sea level for the 21st century based on the latest AOGCM simulations
Authors: Elguindi N. , Giorgi F.
Published: April 2006

We use output from global climate change simulations with seven Atmosphere‐Ocean General Circulation Models (AOGCMs) to assess possible changes in Caspian Sea basin hydrologic budget and corresponding changes in the Caspian Sea Level (CSL) for the 21st century under different greenhouse gas (GHG) emission scenarios (A1b and A2). Although most models project an increase in precipitation over the Volga river basin, where most of the runoff into the Caspian Sea is generated, a steady decline in the CSL is mostly estimated. This is due to large increases in evapotranspiration over land and over the Caspian Sea surface. By the end of the 21st century, the ensemble average of the model‐based estimates suggest a 9 meter drop in the CSL for both scenarios analyzed. This could be potentially devastating for the surrounding region if no adaptation or mitigation measures are taken.
In situ measurements of simultaneous electronic behavior of Cu and Al induced by mechanical deformation
Authors: Li W. , Li D. Y.
Published: April 2006

Studies of mechanical force acting on electrons inside a solid are of both fundamental and practical importance. This is especially emphasized by the recent applications of the Kelvin probing technique to investigate mechanical behavior of surfaces and interfaces. However, the effect of deformation on the electron work function (EWF) and its physical mechanism have not been well understood. In this study, simultaneous responses of the EWF of copper and aluminum to deformation during bending tests were measured in situ. It was demonstrated that in the elastic range, the tensile strain decreased the EWF, whereas compressive strain increased the EWF. However, in the plastic range, the EWF always decreased with strain for both tension and compression deformations. Considering changes in electrostatic energy of a one-dimensional lattice caused by dislocation density, we proposed a simple model and quantitatively established a correlation between the EWF and strain, which is consistent with the experimental observations.
Excitation dependence of photoluminescence due to nonlinear recombination and diffusion
Authors: Reinhart F. K.
Published: April 2006

The photoluminescence yield of undoped semiconductors strongly depends on the excitation power and the intensity distribution. The literature does not address this problem in spite of the fact that quoted recombination lifetimes vary at least over an order of magnitude. A simple cylindrical model based on nonlinear recombination and ambipolar carrier diffusion serves to simulate the photoluminescence yield. The radiative and Auger recombination are responsible for the nonlinearity. Using the controlled Gaussian beam distribution of a He–Ne laser to excite the photoluminescence, we experimentally test the predictions of the calculations on a thin (100nm) GaAs layer embedded in AlxGa1−xAs. These observations demonstrate that the concept of a universal lifetime is not valid for undoped materials having residual impurity concentrations well below 1016cm−3. The lifetime concept also looses its physical significance in strongly pumped materials, where the injected carrier densities are comparable or larger than the background doping.
Heat capacity of tetrahydrofuran clathrate hydrate and of its components, and the clathrate formation from supercooled melt
Authors: Tombari E. , Presto S. , Salvetti G. , Johari G. P.
Published: April 2006

We report a thermodynamic study of the formation of tetrahydrofuran clathrate hydrate by explosive crystallization of water-deficient, near stoichiometric, and water-rich solutions, as well as of the heat capacity, Cp, of (i) supercooled tetrahydrofuran–H2O solutions and of the clathrate hydrate, (ii) tetrathydrofuran (THF) liquid, and (iii) supercooled water and the ice formed on its explosive crystallization. In explosive freezing of supercooled solutions at a temperature below 257K, THF clathrate hydrate formed first. The nucleation temperature depends on the cooling rate, and excess water freezes on further cooling. The clathrate hydrate melts reversibly at 277K and Cp increases by 770J∕molK on melting. The enthalpy of melting is 99.5kJ∕mol and entropy is 358J∕molK. Molar Cp of the empty host lattice is less than that of the ice, which is inconsistent with the known lower phonon frequency of H2O in the clathrate lattice. Analysis shows that Cp of THF and ice are not additive in the clathrate. Cp of the supercooled THF–H2O solutions is the same as that of water at 247K, but less at lower temperatures and more at higher temperatures. The difference tends to become constant at 283K. The results are discussed in terms of the hydrogen-bonding changes between THF and H2O.