bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Effect of Separation Distance between Open Grid Ceiling and Upright Sprinkler Head on Water Distribution
Authors: Yang Leekwang , Lee Seokjae , Ko MinHyeok
Published: February 2025

This study experimentally evaluates the effect of open-grid ceilings on the water-spraying effectiveness of upright sprinkler heads. The work procedure guidelines of the National Fire Agency uniformly stipulate a separation distance of at least 450 mm between open grid ceilings and upright sprinkler heads. However, the National Fire Protection Association (NFPA) specifies different separation distances depending on hazard classifications (light: 450 mm and ordinary: 600 mm). This difference in standards necessitated the verification of the effective spraying performance of sprinkler heads. Therefore, in this study, water distribution and spray volume were measured by varying the separation distances to 300, 450, and 600 mm through spray distribution experiments. The experimental results showed that the 600 mm separation distance met all performance criteria, whereas the 450 mm separation distance failed to meet the standard for the average water collection distribution curve. Notably, the amount of water collected in the 7th collection container decreased by approximately 45% compared to that at the 600 mm distance. These findings suggest that the current National Fire Agency guidelines, which specify a separation distance of 450 mm, may be insufficient to prevent spray obstruction and should be reconsidered.
A Research on the Development of Technology to Provide Air Respirator Status Information using Wireless Communication
Authors: Lee Gunho , Hong Sungchul
Published: February 2025

Firefighter training systems, such as those provided by the National Fire Service Academy, offer various testbeds for skill development. However, there is a notable lack of training technologies that quantitatively support performance evaluation and provide feedback based on physical data generated during training exercises. Air respirators, which are crucial for monitoring the breathing volume of firefighters in training scenarios, currently lack mechanisms to transmit detailed status information externally. This study proposes the integration of wireless communication technology to measure and transmit the pressure data of air respirators consumed during training to an external control system. This advancement is expected to enable the quantitative evaluation of trainee performance in real time. To achieve this goal, a wireless communication-enabled system was developed to transmit air respirator usage data to a field command center within a training testbed. The accuracy and usability of this system were verified through repeated experiments focused on data acquisition and validation.
Vertical Temperature Distribution Property of Hot Current in an Inclined space Connected to an Underground Space
Authors: Park Hyunwoo , Kang Seunggoo
Published: February 2025

This study investigates the temperature distribution property of a hot current in an inclined space connected to a fire room (underground space). A series of experiments were conducted by varying key parameters, including the heat release rate and the width and angle of the inclined space. Consequently, insights into the temperature distribution of the hot current in the inclined space were obtained. Additionally, a quantitative analysis was performed to evaluate the temperature rise distribution of the hot current in the region between the ceiling and the point where the temperature rise reached 20% of its maximum value ΔT(r*)max.
The Politics of Social Research: Institutionalizing Public Funding Regimes in the United States and Britain
Authors: KING DESMOND
Published: July 2002

In the twenty years after 1945 both the United States and Britain created public funding regimes for social science, through the National Science Foundation (NSF) and the Social Science Research Council (SSRC) respectively. The historical and political contexts in which these institutions were founded differed, but the assumptions about social science concurred. This article uses archival sources to explain this comparative pattern. It is argued that the political context in both countries played a key role in the development of the two research agencies. In each country the need politically to stress the neutrality of social research – though for different reasons in each case – produced a bias towards positivist scientific methodology, untempered by ideology. This propensity created the trajectory upon which each country's public funding regime rests.
BANACH SPACES OF CONTINUOUS VECTOR-VALUED FUNCTIONS OF ORDINALS
Authors: Galego Elói Medina
Published: July 2002

Let $X$ be a Banach space and $\xi$ an ordinal number. We study some isomorphic classifications of the Banach spaces $X^\xi$ of the continuous $X$-valued functions defined in the interval of ordinals $[1,\xi]$ and equipped with the supremum norm. More precisely, first we use the continuum hypothesis to give an isomorphic classification of $C(I)^\xi$, $\xi\geq\omega_1$. Then we present a characterization of the separable Banach spaces $X$ that are isomorphic to $X^\xi$, $\forall\xi$, $\omega\leq\xi lt \omega_1$. Finally, we show that the isomorphic classifications of $(C(I)\oplus F^*)^\xi$ and $\ell_\infty(\N)^\xi$, where $F$ is the space of Figiel and $\omega\leq\xi lt \omega_1$ are similar to that of $\R^\xi$ given by Bessaga and Pelczynski.

AMS 2000 Mathematics subject classification: Primary 46B03; 46B20; 46E15
ADAPTATION OF EXTRA-SHORT-DURATION PIGEONPEA IN THE SHORT RAINY SEASON OF A TROPICAL BIMODAL RAINFALL ENVIRONMENT
Authors: Chauhan Y. S. , Atukorala W. D. , Perera K. D. A. , Joseph K. D. S. M. , Saxena K. B. , Johansen C.
Published: July 2002

The adaptation of extra-short-duration (ESD) and short-duration (SD) pigeonpea (Cajanus cajan) genotypes to the short rainy season (late March to late May; yala) was studied in Sri Lanka in 1995 and 1996. Eight ESD and two SD genotypes were sown on two dates in April and May, with and without supplementary irrigation. In addition, pigeonpea ESD genotype ICPL 88039, and SD genotype ICPL 86012, sesame (Sesamum indicum cv. M.I.3), blackgram (Vigna mungo cv. M.I.1) were compared under rainfed zero-tillage conditions after a rice crop at two locations in 1996. Grain yields of the pigeonpea genotypes under rainfed conditions ranged from 0.07 to 0.47 t ha−1 in the early sowings and 0.09 to 0.42 t ha−1 in the late sowings. The irrigated yields reached 1.7 t ha−1 in early sowing and 1.3 t ha−1 in the late sowings. Irrigation differentially influenced the performance of pigeonpea genotypes in both the sowings in 1996. Analysis of pooled data showed highly significant genotype × environment (year–sowing–irrigation combination) interactions. The interaction pattern among genotypes was associated with differences in the length of the reproductive period and the partitioning coefficient of genotypes. ICPL 88039, with the shortest reproductive period and one of the best in partitioning efficiency, recorded maximum mean yield. As a rainfed post-rice crop in farmers’ fields, ICPL 88039 yielded 0.43–1.4 t ha−1 which exceeded yields of SD pigeonpea (0.02–0.88 t ha−1), blackgram (0.03–1.00 t ha−1) and sesame (0–0.09 t ha−1). The results suggest scope for introducing ESD genotypes as a sole crop in the yala season in Sri Lanka since genotypes with short reproductive periods and high partitioning efficiencies are likely to have better adaptation to this season.
On the evolution of recombination and meiosis
Authors: GESSLER DAMIAN D. G. , XU SHIZHONG
Published: July 2002

Theories on the evolution of recombination in regard to its ability
to increase mean fitness require
a consistent source of negative linkage disequilibrium among loci affecting
fitness to show an
advantage to recombination. Here we present evidence that, at least theoretically,
genetic variation
for recombination can spread in very large populations under a strictly
multiplicative-fitness,
deleterious-allele model. The model uses only Mendelian genetics in a multi-locus
context to show
that a dominant gene for recombination can spread when rare and resist
invasion when common.
In non-equilibrium populations driven by Muller's ratchet, the gene
increases its probability of
fixation by increasing the probability of being associated with the best
individuals. This occurs at
an optimal level of recombination. Its action results in both an immediate
and a long-term
advantage to recombination amongst the proto-meiotic organisms modelled.
The genetic
mechanism lends itself naturally to a model for the evolution of meiosis,
where modern-day
gametes are seen as derivative of ancient unicellular organisms.
JUVENILE DELINQUENCY IN COLONIAL KENYA, 1900–1939
Authors: CAMPBELL CHLOE
Published: July 2002

This article examines policy towards juvenile delinquency in colonial Kenya in the interwar period, arguing that juvenile offenders were the subject of scant official interest until the 1930s, when a series of official reports was commissioned and legislation enacted which attempted to modernize the management of juvenile offenders in keeping with current metropolitan policy. This impulse for reform is placed in the context of colonial discourses on eugenics and the effects of urbanization and detribalization on young Africans, arguing that while key metropolitan principles about delinquency retained their influence on transferral to the colony, they were blended with a distinctive colonial rhetoric about African psychology and capacity for development.
PRAYER, PATRONAGE, AND POLITICAL CONSPIRACY: ENGLISH NUNS AND
THE RESTORATION
Authors: WALKER CLAIRE
Published: July 2002

Restoration historiography has so far remained silent regarding the alliance between
the exiled royalists and the recusant religious houses in the Low Countries. This article examines the
assistance provided to the royalist cause by Abbess Mary Knatchbull of the English Benedictine
cloister at Ghent. The correspondence of Charles's leading advisers, most notably Sir Edward Hyde,
reveals the extent to which the conspirators relied upon the nuns' mail service to communicate with their
supporters in England and abroad, and upon the abbess's ability to obtain funds from local financiers.
While the nuns were not central players in the conspiracies of the late 1650s, their activities reveal the
royalists' dependency upon the networks established by Catholic exiles. The article also explores Mary
Knatchbull's motives for devoting so much of her community's temporal and spiritual resources to the
royalist cause. The rewards she sought from the king after 1660 suggest that she had a definite
religious and political agenda which aimed ultimately at Catholic toleration. Therefore the article
raises several important issues about Charles II's and his ministers' links with English Catholics and,
in particular, it points to the important role of women in the hitherto masculine territory of royalist
conspiracy and politics.
Class, Caste, and Gender among Cashew Workers in the South Indian State of Kerala 1930–2000
Authors: Lindberg Anna
Published: July 2002

The main concern of this paper is the issue of women workers' identity and class consciousness. This investigation is principally based on in-depth interviews with three generations of female factory workers. Extremely unequal power relations between capital and labour is insufficient to explain the more pronounced exploitation of female workers over males. In spite of these women having the potential for collective power, their factory lives have been characterized by treatment in constant violation of labour laws. Low-caste female workers have gone through a process of effeminization which has acted to curb their class identity and limit their scope of action. In the process of caste and class emancipation, the question of gender has been neglected by trade union leaders and politicians. The radicalism of males is built upon women's maintaining of the families – a reality which strongly contradicts hegemonic gender discourses and confuses gender identities.
Beyond the Household: Marriage, Household Formation and the Role of Kin and Neighbours
Authors: Wall Richard
Published: July 2002

Autobiographies and diaries have furnished many historians, including those who otherwise eschew qualitative data, with an apposite quote with which to launch their papers. Other historians select extracts from such sources to add colour to arguments advanced initially from the analysis of parish registers or court records. As a major source in their own right, diaries, autobiographies and letters provide the historian with valuable insights into the motivations, conscious or unconscious, of the authors. Such sources are less forthcoming on the perspectives and motivations of other persons whose activities feature in the written record as their motivations have to be teased out from the distorted and necessarily partial account of the author. Nor is it always easy to distinguish exceptional events in the life of a diarist from those which might have been experienced by persons of equivalent status or even more widely. The temptation is to overgeneralize on the basis of limited evidence.

Steven King in “Chance Encounters? Paths to Household Formation in Early Modern England”, has chosen to be particularly ambitious, selecting a limited number of diaries and autobiographies to challenge the applicability of the widely held association between the accumulation of economic resources and age at marriage and the claim that couples in deciding to marry assessed the state of their current resources and their future prospects. From this base Dr King launches a further set of hypotheses concerning the involvement of parents in the choice of their child's marriage partner, changes over time in the density and quality of contacts between kin and with neighbours, and the significance of these factors for the decline in the mean age at marriage in England over the course of the eighteenth century.
The Origins of Colonial Labour Policy in Late Eighteenth-Century Madras
Authors: Ahuja Ravi
Published: July 2002

This article challenges the view that the English East India Company was unable effectively to dominate society in the colonial metropolis of Madras before the end of the eighteenth century. Instead it is argued that colonial interventions, even into the social organization of labour, were persistent in goals and methods and acquired institutional forms in the latter half of the century. Hence an early colonial labour policy is clearly discernible. The ruling block's strategies concerning the regulation of labour were not based on laissez-faire ideas but rather on a paternalistic brand of contemporary English social theory. This ideological disposition found practical expression in interventions into the city's labour relations by means of various “police committees”. Moreover, British legal techniques were used to regulate labour relations in Madras. On the whole, early colonial labour policy was distinguished from contemporary practices in Britain by a far higher level of coercion.
Recycling of crop wastes and green manure and their
impact on yield and nutrient uptake of wetland rice
Authors: KUMAR VINOD , GHOSH B. C. , BHAT RAVI
Published: July 2002

The potential for using crop wastes as a source of nutrients on
the yields of rice grown under
submerged conditions was studied in both field and pot experiments at the
Experimental Farm of the
Agricultural and Food Engineering Department, Indian Institute of Technology,
Kharagpur during
1992/93 and 1993/94. The application of groundnut haulm at 3·0
t/ha, maize stover at 5·0 t/ha,
mustard stover at 3·0 t/ha and green manure at 1·5 t/ha
contributed considerable amounts of
nutrients, which improved components of yield, yield and nutrient uptake
by rice and also improved
the organic carbon (OC) content and available N, P and K in the soil. Yields
and soil fertility were
both further improved when these organic materials were combined with inorganic
fertilizer to supply
the recommended amounts of nutrients, except that inorganic fertilizer
alone did not cause an
increase in the OC content of the soil. In the pot experiment, the production
of NH4-N and NO3-N
was both larger and more consistent when organic and inorganic nutrient
sources were added
together than when inorganic sources alone were used.
Silver Slippers and a Golden Cap: L. Frank Baum's The

Wonderful Wizard of Oz and Historical Memory in American Politics
Authors: RITTER GRETCHEN
Published: July 2002

L. Frank Baum's The Wonderful Wizard of Oz was an

instant success when

it was published in 1900. Baum's quirky and imaginative tale of the
girl

from Kansas and her friends was complemented by W. W. Denslow's

accomplished illustrations to produce the best-selling children's
story of

the 1900 Christmas season. After years of failed endeavors, the book

brought Frank Baum personal prosperity. It also launched a long-lived

and highly successful series of children's books based on the Oz theme.

There were theatrical and cinematic productions as well, the most famous

of which was MGM's 1939 film The Wizard of Oz starring Judy
Garland.

Indeed, the film eventually came to displace the original Oz tale as the

work to which imitators referred. But the books, and especially the first

book, continue to have a popular presence among lovers of Oz.
Dynamic programming to investigate financial impacts of mastitis control decisions in milk production systems
Authors: YALCIN CENGIZ , STOTT ALISTAIR W.
Published: July 2002

An adaptive stochastic dynamic programming model was used to solve
the optimum replacement decision problem for the dairy cow under a range of
alternative mastitis control procedures. The model predicted that reducing milk
yield losses and somatic cell count penalties by using milking machine test, post-milking
teat disinfection and dry cow therapy added approximately £4, £10 and £13
respectively to an original annuity equivalent net present value for the replacement
heifer of £286. Assuming that these procedures also reduced involuntary culling due
to mastitis by 50% added £8·90 to the annuity. This latter figure indicated that an
important part of the benefit of mastitis control procedures might come from a
reduction in the culling risk of persistent clinical cases. We concluded that the
strength of the dynamic programming model in this context was that it provided an
integrated evaluation of the various impacts of each alternative mastitis procedure
in the long term, which is essential for correct economic evaluation of mastitis.
Citrate, calcium, phosphate and magnesium in
sows' milk at initiation of lactation
Authors: KENT JACQUELINE C. , ARTHUR PETER G. , HARTMANN PETER E.
Published: July 2002

Colostrum and milk were collected from ten sows at
frequent intervals
from before farrowing until 9 d after farrowing. Ionized
calcium, pH, and total
concentrations of citrate, calcium, phosphate and magnesium
were measured in
whole milk. The diffusible fraction of the mammary
secretion was separated by
ultrafiltration and was used for the measurement of
diffusible citrate, calcium,
phosphate and magnesium. The pH before farrowing was
5·7, and increased to 6·5 on
day 4 as total calcium and phosphate also increased. Before
farrowing, total and
diffusible citrate were 7·8 and 7·3 mM
respectively, while diffusible phosphate was
11·9 mM, and these concentrations all decreased
during the study period. Total
magnesium ranged between 3·3 and 4·1 mM,
while diffusible magnesium ranged
between 2·0 and 3·1 mM. While these
concentrations and patterns of change of
diffusible calcium and citrate are quite different from
those of women's milk during
the first week after birth, theoretical physicochemical
relationships between diffusible
calcium and citrate, and ionized calcium and
HPO42− were corroborated by these
results. We conclude that diffusible citrate plays an
important role in the determination of the concentration of
diffusible calcium. However, while citrate may
be the major determinant of the total concentration of
calcium in women's milk, this
is not the case in sows' milk.
Insulin secretion and intestinal peptides during lactation in sheep
Authors: FAULKNER ANNE , MARTIN PAMELA A.
Published: July 2002

Intravenous infusions of glucose and/or glucagon-like peptide-1(7–36)-amide (GLP) or somatostatin-28 (S28) were administered to dry and lactating
sheep
and changes in plasma glucose and serum insulin were followed before, during
and
after infusion. Basal serum insulin concentrations were significantly lower
in
lactating sheep but there was no significant difference in plasma glucose
concentrations. During glucose infusion, changes in serum insulin concentrations
were diminished by comparison with those in dry animals. GLP stimulated
insulin
secretion during hyperglycaemia in both dry and lactating sheep but, proportionately,
the response was significantly greater in the lactating animals. S28 inhibited
glucose-stimulated insulin secretion in both dry and lactating sheep and
there was no
significant difference in the extent of the inhibition between the two
physiological
states. S28 infusion also inhibited the secretion of GLP from the intestinal
tract and
this effect was significantly greater in the lactating animals. The results
demonstrate
a difference in response in the lactating animal to GLP compared with S28.
A possible
explanation of the difference is a decreased sensitivity (i.e.
increased Km) of the
pancreas to the insulinotropic effects of GLP but an increased sensitivity
to the
inhibitory effects of S28 at tissues other than the pancreas in lactation.
Sugar formulation effect on available lysine content of dulce de leche
Authors: MALEC LAURA S. , LLOSA RICARDO A. , VIGO MARÍA S.
Published: July 2002

Dulce de leche is a dairy-based confectionery product, widely consumed in
Argentina and other Latin American countries as filling or topping for desserts, cakes
and biscuits (Hansen, 1978; Bouzas, 1997). It is prepared by heat concentration of
whole milk with added sucrose until it reaches 700 g total solids/kg dulce de leche.
Sucrose is usually partly replaced by other sugars (not more than 400 g/kg of total
sugars added according to Normas Mercosur, 1996) to avoid crystallization. Sodium
bicarbonate is added to prevent coagulation of proteins as the pH of the mixture
decreases and the isoelectric pH of proteins increases during heating.

Maillard browning is the main reaction of milk proteins during the manufacture
of dulce de leche. This results in an attractive flavour and colour, but also leads to
less desirable changes, such as loss of nutritional value and formation of toxic
compounds (Rizzi, 1994; Friedman, 1996a). The natural reactants are free amino
groups of milk proteins and lactose. However, as the addition of other reducing
sugars is an accepted practice, the consequences may be quite different depending on
the formulation used. In addition, other reactions leading to crosslinkages between
protein chains contribute to the reduction in nutritional value (Mauron, 1990;
Friedman, 1996b; Finot, 1997). The reduction of nutritional quality of milk proteins
is attributed to the lower digestibility and the biological inactivation or destruction
of essential amino acids. Lysine is the essential amino acid most affected as its free
ε-amino group is very reactive (Hurrell, 1990; Mauron, 1990; Finot, 1997).

Several studies have investigated the physical and rheological characteristics
(Pauletti et al. 1984, 1996), sensory properties (Sabioni et al.
1984; Buera et al. 1990; Hough et al. 1990),
sugar composition and microbiological stability (Ferramondo et
al. 1984) of dulce de leche. However, there is little information about the loss in
available lysine during manufacture (Pavlovic et al. 1994).

The aim of this study was to examine the effects of the nature and quantity of
various sugars commonly used in the manufacture of dulce de leche on the loss of
available lysine.
Absolute instability of the Ekman layer and related rotating
flows
Authors: LINGWOOD R. J.
Published: July 2002

This paper is concerned with the theoretical behaviour of the
laminar Ekman layer and the family of related rotating problems that
includes both the Bödewadt and the von Kármán
boundary-layer flows. Results from inviscid and viscous analyses are
presented. In both cases, within specific regions of the parameter
space, it is shown that the flows are absolutely unstable in the radial
direction, i.e. disturbances grow in time at every radial location
within these regions. Outside these regions, the flows are
convectively unstable or stable. The absolute or convective nature of
the flows is determined by examining the branch-point singularities
of the dispersion relation. The onset of absolute instability is
consistent with available experimental observations of the onset of
laminar–turbulent transition in these flows.
Pattern formation in weakly damped parametric surface waves
Authors: ZHANG WENBIN , VIÑALS JORGE
Published: July 2002

We present a theoretical study of nonlinear pattern formation in

parametric surface waves for fluids of low viscosity, and in the limit
of

large aspect ratio. The

analysis is based on a quasi-potential approximation to the equations governing

fluid motion, followed by a multiscale asymptotic expansion in the distance
away

from threshold. Close to onset, the asymptotic expansion yields an amplitude
equation

which is of gradient form, and allows the explicit calculation of the functional

form of the cubic nonlinearities. In particular, we find that three-wave
resonant

interactions contribute significantly to the nonlinear terms, and therefore
are

important for pattern selection. Minimization of the associated Lyapunov
functional

predicts a primary bifurcation to a standing wave pattern of square symmetry
for

capillary-dominated surface waves, in agreement with experiments. In addition,
we

find that patterns of hexagonal and quasi-crystalline symmetry can be stabilized
in

certain mixed capillary–gravity waves, even in this case of single-frequency

forcing. Quasi-crystalline patterns are predicted in a region of parameters

readily accessible experimentally.
Collision of two deformable drops in shear flow
Authors: LOEWENBERG M. , HINCH E. J.
Published: July 2002

A boundary integral formulation is used to investigate the interaction

between a

pair of deformable drops in a simple shear flow. The interactions do not
promote

appreciably the breakup of the drops. For certain ratios of the viscosities
of

the drops

and the suspending fluid, the lubrication gap that separates the two drops

can diminish

rapidly in the extensional quadrant of the flow. Slight deformation endows
the drops

with an apparent short-range repulsive interaction: drop coalescence requires
van

der Waals attraction which was not included in this study. From the trajectories
of

different collisions, the self-diffusion coefficients that describe the

cross-flow migration

of the non-Brownian drops in a dilute sheared emulsion are obtained.

The self-diffusivities are very anisotropic, depend strongly on the viscosity

ratio, and depend modestly on the shear rate.
Lubrication flows between spherical particles
colliding in a compressible non-continuum gas
Authors: GOPINATH ARVIND , CHEN SHING B. , KOCH DONALD L.
Published: July 2002

The low-Reynolds-number collision and rebound of two rigid
spheres moving in an
ideal isothermal gas is studied in the lubrication limit. The
spheres are non-Brownian
in nature with radii much larger than the mean-free path of the
molecules. The nature
of the flow in the gap between the particles depends on the relative magnitudes of
the minimum gap thickness, h′o,
the mean-free path of the bulk gas molecules, λo,
and the gap thickness at which compressibility effects become important,
hc. Both
the compressible nature of the gas and the non-continuum nature of the flow in the
gap are included and their effects are studied separately and in combination. The
relative importance of these two effects is characterized by a dimensionless number,
αo≡
(hc/λo).
Incorporation of these effects in the governing equations leads to a
partial differential equation for the pressure in the gap as a function
of time and radial
position. The dynamics of the collision depend on αo,
the particle Stokes number, Sto,
and the initial particle separation,
h′o. While a continuum
incompressible lubrication
force applied at all separations would prevent particle contact, the
inclusion of either
non-continuum or compressible effects allows the particles to contact. The critical
Stokes number for particles to make contact, St1,
is determined and is found to have the form St1=
2 [ln(h′o/l)
+C(αo)], where
C(αo) is an O(1) quantity
and l is a characteristic length scale defined by l≡
hc(1+αo)/
αo.
The total energy dissipated during the approach and rebound of two particles
when Sto[Gt ]St1 is also determined
in the event of perfectly elastic or inelastic solid-body collisions.
Bubbles rising in line: why is the first

approximation so bad?
Authors: HARPER J. F.
Published: July 2002

An analytical theory is given for the viscous wake behind a spherical

bubble rising steadily in a pure liquid at high Reynolds number, and for
that

wake's effect on

the motion of a second bubble rising underneath the first. Previous theoretical

work on this subject consists of just two papers: a first approximation
ignoring

wake vorticity diffusion between the bubbles, and a full numerical solution
avoiding

simplifying approximations (apart from that of spherical shape of the bubbles).
A

second approximation is now found; it removes much of the discrepancy between

the first approximation and the full solution. The leading-order calculation
of wake

vorticity diffusion uses a transformation of the independent variables
which appears

to be new. Experimental work to date has disagreed with all the theoretical
work, but

it addresses a somewhat different problem: a line of many bubbles.
Stability of interfacial waves in aluminium reduction cells
Authors: DAVIDSON P. A. , LINDSAY R. I.
Published: July 2002

We investigate the stability of interfacial waves in
conducting fluids under the influence
of a vertical current density, paying particular attention to aluminium
reduction cells
in which such instabilities are commonly observed. We develop a wave equation

for the interface in which the Lorentz force is expressed explicitly in
terms of the
fluid motion. Our wave equation differs from previous models, most notably
that
developed by Urata (1985), in that earlier formulations rested on a more
complex,
implicit coupling between the fluid motion and the Lorentz force. Our formulation

furnishes a number of quite general stability results without the need
to resort to
Fourier analysis. (The need for Fourier analysis typifies previous studies.)
Moreover,
our equation supports both travelling and standing waves. We investigate
each in turn.

We obtain three new results. First, we show that travelling waves may
become
unstable in the presence of a uniform, vertical magnetic field. (Our travelling
waves are
quite different to those discovered by previous investigators (Sneyd 1985
and Moreau
& Ziegler 1986) which require more complex magnetic fields to become
unstable.)
Second, in line with previous studies we confirm that standing waves may
also become
unstable. In this context we derive a simple energy criterion which shows
which types
of motion may extract energy from the background magnetic field. This indicates

that a rotating, tilted interface is particularly prone to instability,
and indeed such a
motion is often seen in practice. Finally, we use Gershgorin's theorem
to produce a
sufficient condition for the stability of standing waves in a finite domain.
This allows
us to place a lower bound on the critical value of the background magnetic
field at
which an instability first appears, without solving the governing equations
of motion.
Observations of coagulation in isotropic turbulence
Authors: BRUNK BRETT K. , KOCH DONALD L. , LION LEONARD W.
Published: July 2002

Turbulent-shear-induced coagulation of monodisperse particles was
examined
experimentally in the nearly isotropic, spatially decaying turbulence generated
by an
oscillating grid. The 3.9 μm polystyrene microspheres used in the experiments
were
made neutrally buoyant and unstable by suspending them in a density-matched
saline
solution. In this way, particle settling, double-layer repulsion and particle
inertia were
negligible and the effect of turbulent shear was isolated. The coagulation
rate was
measured by monitoring the loss of singlet particles as a function of time
and reactor
turbulence intensity. By restricting consideration to experimental conditions
where the
singlet concentration was in excess, the effect of higher-order aggregate
(i.e. triplet)
formation was negligible and nonlinear regression using an integral rate
expression
that included terms for doublet formation and breakup was used to obtain
the
turbulent coagulation rate constant. The strength of the van der Waals
attractions was
characterized with the Hamaker constant obtained from Brownian coagulation

experiments. Since particle bulk mixing was fast compared to the coagulation
rate, the
observed coagulation rate constants were averages over the local coagulation
rates
within the grid-stirred reactor. Knowledge of the spatial variation of
turbulence within
the reactor was necessary for quantitative prediction of the experiments
because model
predictions for the coagulation rate are nonlinear functions of shear rate.
The
investigation was conducted with particles smaller than the length scales
of turbulence
and since the smallest turbulent length scales, the Kolmogorov scales,
have the highest
shear rate they controlled the rate of particle aggregation. The distribution
of the
Kolmogorov shear rate at various grid oscillation frequencies was obtained
by
measuring the turbulent kinetic energy (E) using acoustic Doppler
velocimetry and
relating E to the Kolmogorov shear rate using scaling arguments.
The experimentally
measured turbulent coagulation rate constants were significantly lower
than theoretical
predictions that neglect interparticle interactions; however, simulations
that included
particle interactions showed excellent agreement with the experimental
results. The
favourable comparison provides evidence that the computer simulations capture
the
important physics of turbulent coagulation. That is, particle transport
on length scales
comparable to the particle radius controls the rate of turbulent shear
coagulation and
particle interactions are significant.
Numerical investigation of the turbulent boundary layer over a bump
Authors: WU XIAOHUA , SQUIRES KYLE D.
Published: July 2002

Large-eddy simulation (LES) has been used to calculate the flow
of a statistically
two-dimensional turbulent boundary layer over a bump. Subgrid-scale stresses
in the
filtered Navier–Stokes equations were closed using the dynamic eddy
viscosity model.
LES predictions for a range of grid resolutions were compared to the experimental

measurements of Webster et al. (1996). Predictions of the mean
flow and turbulence
intensities are in good agreement with measurements. The resolved turbulent
shear
stress is in reasonable agreement with data, though the peak is over-predicted
near
the trailing edge of the bump. Analysis of the flow confirms the existence
of internal
layers over the bump surface upstream of the summit and along the downstream

trailing at plate, and demonstrates that the quasi-step increases in skin
friction
due to perturbations in pressure gradient and surface curvature selectively
enhance
near-wall shear production of turbulent stresses and are responsible for
the
formation of the internal layers. Though the flow experiences a strong
adverse pressure
gradient along the rear surface, the boundary layer is unique in that intermittent

detachment occurring near the wall is not followed by mean-flow separation.
Certain
turbulence characteristics in this region are similar to those previously
reported in
instantaneously separating boundary layers. The present investigation also
explains the
driving mechanism for the surprisingly rapid return to equilibrium over
the trailing
flat plate found in the measurements of Webster et al. (1996),
i.e. the simultaneous
uninterrupted development of an inner energy-equilibrium region and the
monotonic
decay of elevated turbulence shear production away from the wall. LES results
were
also used to examine response of the dynamic eddy viscosity model. While

subgrid-scale dissipation decreases/increases as the turbulence is

attenuated/enhanced, the
ratio of the (averaged) forward to reverse energy transfers predicted by
the model is
roughly constant over a significant part of the layer. Model predictions
of backscatter,
calculated as the percentage of points where the model coefficient is negative,
show a
rapid recovery downstream similar to the mean-flow and turbulence quantities.
On the stability of the dynamical system ‘rigid
body + inviscid fluid’
Authors: VLADIMIROV V. A. , ILIN K. I.
Published: July 2002

In this paper we study a dynamical system consisting of a rigid body and an inviscid
incompressible fluid. Two general configurations of the system are considered: (a) a
rigid body with a cavity completely filled with a fluid and (b) a rigid body surrounded
by a fluid. In the first case the fluid is confined to an interior (for the body) domain and
in the second case it occupies an exterior domain, which may, in turn, be bounded by
some fixed rigid boundary or may extend to infinity. The aim of the paper is twofold:
(i) to develop Arnold's technique for the system ‘body + fluid’ and (ii) to obtain
sufficient conditions for the stability of steady states of the system. We first establish
an energy-type variational principle for an arbitrary steady state of the system. Then
we generalize this principle for states that are steady either in translationally moving
in some fixed direction or rotating around some fixed axis coordinate system. The
second variations of the corresponding functionals are calculated. The general results
are applied to a number of particular stability problems. The first is the stability
of a steady translational motion of a two-dimensional body in an irrotational flow.
Here we have found that (for a quite wide class of bodies) the presence of non-zero
circulation about the body does not affect its stability – a result that seems to be new.
The second problem concerns the stability of a steady rotation of a force-free rigid
body with a cavity containing an ideal fluid. Here we rediscover the stability criterion
of Rumyantsev (see Moiseev & Rumyantsev 1965). The complementary problem –
when a body is surrounded by a fluid and both body and fluid rotate with constant
angular velocity around a fixed axis passing through the centre of mass of the body – is
also considered and the corresponding sufficient conditions for stability are obtained.
Steady flow in a dividing pipe
Authors: BLYTH M. G. , MESTEL A. J.
Published: July 2002

The high Reynolds number flow through a circular pipe divided along a diameter
by a semi-infinite splitter plate is considered. Matched asymptotic expansions are
used to analyse the developing flow, which is decomposed into four regions: a
boundary layer of Blasius type growing along the plate, an inviscid core, a viscous
layer close to the curved wall and a nonlinear corner region. The core solution
is found numerically, initially in the long-distance down-pipe limit and thereafter
the full problem is solved using down-pipe Fourier transforms. The accuracy in the
corners of the semicircular cross-section is improved by subtracting out the singularity
in the velocity perturbation. The linear viscous wall layer is solved analytically in
terms of a displacement function determined from the core. A plausible structure
for the corner region and equations governing the motion therein are presented
although no solution is attempted. The presence of the plate has little effect ahead
of the bifurcation, but wall shear on the curved wall is found to increase from its
undisturbed value downstream.
Commerce and Imperial Decline:
Spanish Trade with Spanish America, 1797–1820
Authors: FISHER JOHN R.
Published: July 2002

This article analyses, first, the principal features of Spain's
commercial
policies towards Spanish America in 1797–1820, and, second, the value,
nature
and distribution of the trade that survived in this period, despite prolonged

international warfare, the admission of neutral shipping, and internal
strife from
1808 in both Spain and America. Like the author's earlier
studies of ‘free trade’
in the period 1778–96, its principal sources are shipping registers
and associated
inter-ministerial correspondence in the Archivo General de Indias of Sevilla.
Its
main conclusions are that: (1) despite ambivalence and uncertainty in Spain
about
commercial policy, trade with Spanish America was more buoyant in 1797–1820

than previously realised; (2) nevertheless, by the first decade of the
nineteenth
century most parts of Spanish America were enjoying
de facto, if not de jure, free
trade with foreigners; (3) consequently, commercial discontent was not
a key
factor in the process of emancipation from Spain, particularly in the viceroyalties

of New Spain and Peru which received some 70% of exports from Spain in
this period.
Linguists play catchup with evolution
Authors: BICKERTON DEREK
Published: July 2002

Donald Loritz, How the brain evolved language. New York & Oxford: Oxford
University Press, 1999. Pp. 227.

Lyle Jenkins, Biolinguistics : exploring the biology of language. Cambridge:
Cambridge University Press, 2000. Pp. xiii+264.

In the course of reviewing recent books on the evolution of language and
communication (Dunbar 1996, Hauser 1996, Deacon 1997) I have had
occasion to note that relatively few writers on these topics know much about
linguistics, and to wish that more of them did. I should have remembered the
old adage that one shouldn't wish for things - one might get them.

For more than a century, linguists honored the Linguistic Society of
Paris's ban on all discussion of language evolution; other disciplines went
ahead with it regardless. Now that the centrality of language evolution to any
study of our species is becoming apparent, linguists are desperately trying to
play catchup, and the two volumes reviewed here both appeared in the last
couple of years. Both authors are linguists, albeit hyphenated ones. Donald
Loritz teaches computational linguistics at Georgetown University; his
doctorate was in psycholinguistics. Lyle Jenkins works in the Biolinguistics
Institute in Cambridge, MA; however, his doctorate was in unhyphenated
linguistics. It would be difficult to find two authors whose ideas were more
diametrically opposed.
Elucidation of a telic infinitive
Authors: WHELPTON MATTHEW
Published: July 2002

In this paper, I consider the semantics of a modifier infinitive in English, related to the more widely discussed Rationale Clause (see especially Faraci 1974, Jones 1991). I argue that the semantics of this infinitive (a Telic Clause) derives from the properties of the predicate which heads it (TELOS). I characterize TELOS, within a Davidsonian event semantics, as a pure relation between events and argue against the view that the word only, which often prefaces the Telic Clause, is in fact the head of the construction. I explore the conditions on reference which apply to TELOS. As well as offering an account of a little-discussed construction, therefore, this paper is intended as a contribution to our understanding of the place of argument structure in event semantics.
Managing multiple minority problems in a divided society: the
Nigerian experience
Authors: Osaghae Eghosa E.
Published: July 2002

The management of ethnic problems has tended to be complicated
by
the complex ethnic situations which give rise to them. It is known for

example that ethnicity rarely exists in a pure form, being usually
combined with other conflict-generating cleavages, such as religion,
race, class and regionalism, in mutually reinforcing ways. Ethnicity is

also situational, fluid and intermittent, while ethnic boundaries are
constantly changing. In addition, levels of ethnic consciousness and
political mobilisation differ among groups, for reasons of different
perceptions of relative privileges or deprivation, history of inter-group

relations, effects of state policies or actions, dispositions and strategies

adopted by other competing groups, and so on. For these and other
reasons, common stimuli like democratisation, economic prosperity or
decline, and transformatory social processes, all of which impact on
ethnicity, produce different effects on ethnic groups.

These differences and complexities have implications for the
management of ethnic problems and conflicts. For one thing, ethnic
conflicts tend to be intractable, especially where their management
does not take full account of their complexity. The temptation to
proffer catch-all management formulae, such as federalism, bills of
rights, secularity and so on, as if all ethnic conflicts can be dealt with

uniformly or in one fell swoop, is the product of the fallacy of
oversimplification. It goes without saying that conflict situations must

be properly understood for the appropriate ‘therapies’ to be
formulated
and applied. If this is done, it will be found that more nuanced solutions

are required to cope with the demands of the complex situations.
Z-pinch Vlasov-fluid equilibria
including sheared-axial flow
Authors: CHANNON S. W. , COPPINS M.
Published: July 2002

New solutions are presented to the equilibrium Vlasov-fluid equations
in Z-pinch geometry that include the effect of sheared axial ion flow. These are
different to previous Vlasov-fluid equilibria in that the ion distribution function
shows an axial temperature anisotropy. Examples of three new classes of equilibria
are calculated, these being the anisotropic-parabolic (constant current density)
and Bennett (constant relative speed) profiles and a set of profiles resulting from
assuming that the ion fluid velocity is given by (b1+rp) for b1=−0.5 and p>1.
Envelope nonlinear drift structures in a
non-equilibrium plasma near the boundary of marginal stability
Authors: DAVYDOVA TATIANA A. , PANKIN ALEXEI YU.
Published: July 2002

An explosive instability of the ion-temperature-gradient
(ITG)-driven modes
(ηi modes) near the boundary of marginal
stability is considered as a driving mechanism for subcritical
turbulence. It is shown that boundedness of the wave interaction
region leads to saturation of the instability. The possibility of
coherent soliton-like
structure formation in both slab and toroidal geometries is
demonstrated by numerical simulation. An analytical soliton solution
is found in some special cases.
Multidimensional simple waves in gas dynamics
Authors: WEBB G. M. , RATKIEWICZ R. , BRIO M. , ZANK G. P.
Published: July 2002

A formalism for multidimensional simple waves in gas dynamics using
ideas
developed by Boillat is investigated. For simple-wave solutions, the physical

variables depend on a single function   (r, t).

The wave phase   (r, t) is implicitly
determined by an equation of the form
f( )=r·n( )−λ( )t,

where n( ) denotes
the normal to the wave front, λ is the characteristic speed of the
wave mode of
interest, r is the position vector, t is the time,
and the function f( ) determines
whether the wave is a centred (f( )=0) or a non-centred
(f( )≠0) wave.
Examples are given of time-dependent vortex waves, shear waves and sound

waves in one or two space dimensions. The streamlines for the wave reduce
to
two coupled ordinary differential equations in which the wave phase  
plays the
role of a parameter along the streamlines. The streamline equations are

expressed in Hamiltonian form. The roles of Clebsch variables, Lagrangian

variables, Hamiltonian formulations and characteristic surfaces are briefly

discussed.