478 research outputs found
Fusion and the cosmos
In the following investigation we pay special attention to the role of selforganization
in fusion plasma physics and in the cosmos. We present a
new approach to the expansion of the universe. Formally the technique
developed relies on our experience from treating hot fusion plasmas. We
account for the possibility that the universe, as it seems, could have a fi-
nite life-time (even if it is counted in billions of years), and combine this
assumption with the experimental observation that the velocity of separation
of distant galaxies is proportional to the distance between the galaxies
(the Hubble law). By analysis of a NL PDE (nonlinear partial differential
equation) we succed in proving that the crucial value of an exponent has a
simple linear relationship with the Hubble constant. It is recognized that the
scale-length that we use as a measure of the expansion is equivalent to
the Einstein radius of curvature. The final results suggest that the Hubble
law should be extended by a factor, which could have an explosive tendency
of growth in time (open universe), or a decaying character (closed
universe). The possibility of reversed expansion or an oscillating universe
“cosmic pendulum” is also discussed.Особлива увага в даному дослідженні приділяється ролі самоорганізації у фізиці термоядерної плазми і у Всесвіті. Представлено новий підхід до проблеми розширення Всесвіту. Формально розвинений підхід ґрунтується на досвіді, отриманому при вивченні гарячої термоядерної плазми. Ми враховуємо можливість того, що Всесвіт, як видається, може мати скінчений час життя (навіть якщо рахунок йде на мільярди років), та поєднуємо це припущення з експериментальним фактом, що швидкість розбігання віддалених галактик пропорційна до віддалі між ними (закон Габбла). На основі аналізу неоднорідного диференціального рівняння у частинних похідних нам вдалося довести, що критичне значення показника пов’язане зі сталою Габбла простим лінійним співвідношенням. Виявлено, що масштаб, який ми використовуємо як міру розширення Всесвіту, є еквівалентним до ейнштейнівського радіусу кривизни. З кінцевих результатів випливає, що закон Габбла слід доповнити множником, який може мати вибухоподібну тенденцію росту з часом (відкритий Всесвіт), або спадний характер (замкнений Всесвіт). Обговорюється можливість оборотнього розширення або осцилюючого Всесвіту (космічний маятник)
Human-animal interactions during on-farm truck loading of finishing pigs for slaughter transport
Finishing pigs and transport drivers (TDs) interact closely when pigs are loaded for transport, which can be very stressful for both. We aimed to investigate relationships between TD handling actions and pig behaviours during loading for slaughter transport. In total 2,476 finishing pigs were loaded by 18 TDs (2 women, 16 men) during 18 loadings at 18 pig farms in Sweden over a 6 month period. Tactile, vocal and visual TD handling actions were recorded and characterized as 'moderately-strongly negative', 'mildly negative' or 'positive'. In the pigs, 'stress related', 'flow', 'disrupted flow' and 'relaxed' behaviours were recorded in all animals within 2 m in front of the TDs, using continuous video recordings, and summarized in 5-s intervals. Logistic models were constructed to estimate associations between actions and behaviours, including the preceding one or two intervals. The odds of stress related behaviour in the pigs was found to increase 5.4 and 4.1 times when a moderately-strongly negative and any negative TD action, respectively, occurred in the same interval. When a moderately-strongly negative and any negative TD action occurred in the preceding interval, the odds of stress related behaviour increased 2.0 times and 1.4 times, respectively. The odds of disrupted flow increased 1.6 times when any negative TD action occurred in the same interval. Furthermore, the odds of moderately-strongly negative TD action increased 5.4, 3.4 and 1.9 times, and the odds of any negative TD action increased 3.6, 2.9 and 2.1 times when stress related pig behaviour occurred in the same interval, the preceding interval and the interval before that, respectively. Pos-itive TD action in the same or preceding interval was associated with relaxed pig behaviour. This study suggests a reciprocal relationship between TD actions and pig behaviour, which provides an opportunity to improve TD actions through training in order to reduce stress behaviours in pigs
Understanding and protecting vulnerable financial consumers
This article considers how consumer protection law and policy should address the interests of particularly vulnerable financial consumers. Specifically, the article proposes a taxonomy of vulnerability which helps to identify (a) what makes consumers particularly vulnerable, and (b) how consumer protection law and consumer policy (broadly understood) can respond to these causes in a way that provides such consumers with appropriate protection. Changes to economic conditions, legal requirements on traders and our understanding of consumer behaviour make discussion of these issues particularly topical. There is little doubt that finding solutions is extremely difficult. Trade-offs are necessary and some enduring factors that contribute to vulnerability, in particular poverty, sometimes appear intractable. Nevertheless, it is submitted that by identifying clearly both why consumers are vulnerable and how the factors that lead to such vulnerability can be addressed, it is possible to construct an environment which respects consumer choice while ensuring that the most vulnerable are protected appropriately
Physical workload and psychosocial working conditions in Swedish pig transport drivers
Working conditions of 20 Swedish pig transport drivers (PTD) were assessed by a questionnaire, a workshop, and recorded postures and movements during on-farm loading, driving, unloading at abattoir and vehicle cleaning. High arm positions and high frequencies of shoulder problems indicated an excessive physical load on shoulders. Extreme crouching postures inside vehicles and high frequencies of lower back problems indicated high load on the back of PTDs. Inadequate design of on-farm loading areas was associated with knee discomfort. Observed variation in workload between PTDs could be explained by differences in physical working environment and pig handling practices. PTDs reported high job satisfaction and commitment although conflicts with farmers and official veterinarians, as well as regulatory conflicts were emphasized. We conclude that issues of inadequate farm and abattoir facilities, stakeholder conflicts and insufficient training in animal handling need to be addressed to ensure sustainable PTD working conditions
A certain class of Laplace transforms with applications to reaction and reaction-diffusion equations
A class of Laplace transforms is examined to show that particular cases of
this class are associated with production-destruction and reaction-diffusion
problems in physics, study of differences of independently distributed random
variables and the concept of Laplacianness in statistics, alpha-Laplace and
Mittag-Leffler stochastic processes, the concepts of infinite divisibility and
geometric infinite divisibility problems in probability theory and certain
fractional integrals and fractional derivatives. A number of applications are
pointed out with special reference to solutions of fractional reaction and
reaction-diffusion equations and their generalizations.Comment: LaTeX, 12 pages, corrected typo
Multi-user video streaming using unequal error protection network coding in wireless networks
In this paper, we investigate a multi-user video streaming system applying unequal error protection (UEP) network coding (NC) for simultaneous real-time exchange of scalable video streams among multiple users. We focus on a simple wireless scenario where users exchange encoded data packets over a common central network node (e.g., a base station or an access point) that aims to capture the fundamental system behaviour. Our goal is to present analytical tools that provide both the decoding probability analysis and the expected delay guarantees for different importance layers of scalable video streams. Using the proposed tools, we offer a simple framework for design and analysis of UEP NC based multi-user video streaming systems and provide examples of system design for video conferencing scenario in broadband wireless cellular networks
Carbon release by selective alloying of transition metal carbides
We have performed first principles density functional theory calculations on
TiC alloyed on the Ti sublattice with 3d transition metals ranging from Sc to
Zn. The theory is accompanied with experimental investigations, both as regards
materials synthesis as well as characterization. Our results show that by
dissolving a metal with a weak ability to form carbides, the stability of the
alloy is lowered and a driving force for the release of carbon from the carbide
is created. During thin film growth of a metal carbide this effect will favor
the formation of a nanocomposite with carbide grains in a carbon matrix. The
choice of alloying elements as well as their concentrations will affect the
relative amount of carbon in the carbide and in the carbon matrix. This can be
used to design the structure of nanocomposites and their physical and chemical
properties. One example of applications is as low-friction coatings. Of the
materials studied, we suggest the late 3d transition metals as the most
promising elements for this phenomenon, at least when alloying with TiC.Comment: 9 pages, 6 figure
Electronic structure investigation of Ti3AlC2, Ti3SiC2, and Ti3GeC2 by soft-X-ray emission spectroscopy
The electronic structures of epitaxially grown films of Ti3AlC2, Ti3SiC2 and
Ti3GeC2 have been investigated by bulk-sensitive soft X-ray emission
spectroscopy. The measured high-resolution Ti L, C K, Al L, Si L and Ge M
emission spectra are compared with ab initio density-functional theory
including core-to-valence dipole matrix elements. A qualitative agreement
between experiment and theory is obtained. A weak covalent Ti-Al bond is
manifested by a pronounced shoulder in the Ti L-emission of Ti3AlC2. As Al is
replaced with Si or Ge, the shoulder disappears. For the buried Al and
Si-layers, strongly hybridized spectral shapes are detected in Ti3AlC2 and
Ti3SiC2, respectively. As a result of relaxation of the crystal structure and
the increased charge-transfer from Ti to C, the Ti-C bonding is strengthened.
The differences between the electronic structures are discussed in relation to
the bonding in the nanolaminates and the corresponding change of materials
properties.Comment: 15 pages, 8 figure
Reaction-diffusion systems and nonlinear waves
The authors investigate the solution of a nonlinear reaction-diffusion
equation connected with nonlinear waves. The equation discussed is more general
than the one discussed recently by Manne, Hurd, and Kenkre (2000). The results
are presented in a compact and elegant form in terms of Mittag-Leffler
functions and generalized Mittag-Leffler functions, which are suitable for
numerical computation. The importance of the derived results lies in the fact
that numerous results on fractional reaction, fractional diffusion, anomalous
diffusion problems, and fractional telegraph equations scattered in the
literature can be derived, as special cases, of the results investigated in
this article.Comment: LaTeX, 16 pages, corrected typo
Results from the CERN pilot CLOUD experiment
During a 4-week run in October–November 2006, a pilot experiment was performed at the CERN Proton Synchrotron in preparation for the Cosmics Leaving OUtdoor Droplets (CLOUD) experiment, whose aim is to study the possible influence of cosmic rays on clouds. The purpose of the pilot experiment was firstly to carry out exploratory measurements of the effect of ionising particle radiation on aerosol formation from trace H2SO4 vapour and secondly to provide technical input for the CLOUD design. A total of 44 nucleation bursts were produced and recorded, with formation rates of particles above the 3 nm detection threshold of between 0.1 and 100 cm−3 s−1, and growth rates between 2 and 37 nm h−1. The corresponding H2SO4 concentrations were typically around 106 cm−3 or less. The experimentally-measured formation rates and H2SO4 concentrations are comparable to those found in the atmosphere, supporting the idea that sulphuric acid is involved in the nucleation of atmospheric aerosols. However, sulphuric acid alone is not able to explain the observed rapid growth rates, which suggests the presence of additional trace vapours in the aerosol chamber, whose identity is unknown. By analysing the charged fraction, a few of the aerosol bursts appear to have a contribution from ion-induced nucleation and ion-ion recombination to form neutral clusters. Some indications were also found for the accelerator beam timing and intensity to influence the aerosol particle formation rate at the highest experimental SO2 concentrations of 6 ppb, although none was found at lower concentrations. Overall, the exploratory measurements provide suggestive evidence for ion-induced nucleation or ion-ion recombination as sources of aerosol particles. However in order to quantify the conditions under which ion processes become significant, improvements are needed in controlling the experimental variables and in the reproducibility of the experiments. Finally, concerning technical aspects, the most important lessons for the CLOUD design include the stringent requirement of internal cleanliness of the aerosol chamber, as well as maintenance of extremely stable temperatures (variations below 0.1 _C)
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