NUMERICAL ANALYSIS OF INDIRECT ICE STORAGE SYSTEMS PERFORMANCE

A numerical investigation regarding the charging process behavior occurring in a typical indirect ice storage tank is presented. It consists of analyzing the heat transfer and removal of energy, applicable to storage systems, which are chiller-based. In this sense the secondary coolant circulates through a heat exchanger that is submerged in a tank of water and it is used to freeze (charge) the phase-change material (water), which never leaves the storage tank. The thermal exchange process is investigated considering the storage tank in two different positions. In the first one the storage tank is in the vertical position, while for the second, it is horizontally positioned. The storage tank is represented by a channel formed by parallel flat plates, one of which is the heat exchanger. Our task is to provide helpful qualitative results for the heat transfer performance of ice storage tanks. The results are analysed through streamlines and isotherms, for specific instants of time. Further, the heat transfer effectiveness, average heat flux and solid formed at one of the two plates of the channel, are compared for the vertical and horizontal positions of the channel

Tick paralysis in the Karoo areas of South Africa

1. Four forms of tick paralysis in South Africa may be distinguished, which differ as regards the clinical picture and are associated with four distinct tick species. 2. The literature dealing with tick paralysis in South Africa is briefly reviewed. 3. The seasonal occurrence of the adults, nymphae and larvae of I. rubicundus is given. 4. The adult is both nocturnal and diurnal and it is possible to demonstrate a peak in diurnal activity between 10 a.m. and 2 p.m. 5. The immature stages are exclusively nocturnal. 6. The influence of temperature upon larval activity is demonstrated graphically. 7. A host list is given which shows that the Menotyphla and Lagomorpha play the main role as hosts of the immature stages. The Artiodactyla constitute the main hosts of the adult tick amongst the wild animals. The tick is not found on birds. 8. The attachment sites of the adult stages on adult sheep and lambs are given and the chances of reaching full engorgement on the different regions of the body of the sheep arc discussed. The preferential sites for I. rubicundus and I. ricinus are compared and the differences in habit of these two species on sheep described. 9. The time required by the female to reach full engorgement in different situations on the bodies of sheep is given. 10. The stages of engorgement normally observed are described and exceptions to this rule are discussed. 11. The percentage of females that fail to reach full engorgement on sheep is shown to increase with the time the sheep spends in tick-infested veld. 12. The influence of copulation upon the rate of engorgement is discussed. 13. The use of tethered sheep in tick-infested veld as a means of tick survey is discussed. 14. An improvement on the standard technique of dragging for ticks, for use in the Karoo shrub, is described. 15. The attraction of different materials to I. rubicundus tested by the dragging technique in the field has been investigated. 16. Seven species of ticks found during the course of dragging are noted. 17. The uniformity of distribution of I. rubicundus larvae in the field is discussed. 18. The factors responsible for the losses of ticks from the apparatus during the course of dragging are demonstrated graphically and discussed. 19. A map showing the distribution of I. rubicundus and the occurrence of tick paralysis in relation to veld (pasture) types in a selected area in the Sneeuberg Range is included. 20. The ecological investigations of overseas workers on other tick species are reviewed briefly for comparison with the findings relating to I. rubicundus in South Africa. 21. An association between tick incidence and deterioration of pasture in the case of I. rubicundus is found to follow a pattern similar to that of I. ricinus in Britain. 22. The hatching and survival of the larvae of I. rubicundus are shown to represent phases of the life-cycle more susceptible to unsuitable environment than any other stage. 23. Experimental studies on the hatching and survival of eggs placed in decaying plant material under certain shrubs and rank grasses are described and compared with the differences observed when grasses are not allowed to become rank. 24. Significant differences in tick densities are shown to occur in different naturally-infested veld types. Sweet-grass mountain veld, constituting the original coverage of all mountains in the area under investigation, is not suited to the completion of the life-cycle of the tick. 25. The role played by Rhus erosa in the creation of suitable environmental conditions for the tick is pointed out. 26. The time required for bringing about an alteration in the existing plant associations by applying different methods of pasture management is discussed. 27. The influence of the regular dipping of sheep upon the incidence of I. rubicundus is demonstrated. 28. The exclusion of sheep from tick-infested camps during the active season of I. rubicundus is shown to have no effect upon the incidence of the tick. 29. The influence of veld fires upon the tick is pointed out. 30. The recommendations of other investigators for the control of I. rubicundus by dipping are compared with the application of dipping to the control of I. ricinus. 31. The specific efficacy of insecticides against the tick as found by a laboratory method, the ability of the insecticide to diffuse along the wool fibres and the quantity of insecticide deposited in the fleece rather than the concentration of the wash in the dipping tank, are shown to be the decisive factors governing the period of protection obtained against I. rubicundus. 32. BHC is shown to be capable of protecting woolled sheep against I. rubicundus for a period exceeding 18 weeks when 4·75 gm. of the gamma isomer is deposited per sheep. 33. Dieldrin is shown to protect woolled sheep for approximately 11 weeks when 7 gm. of the active ingredient is deposited per sheep. 34. The protection of sheep against Rhipicephalus evertsi and Hyalomma spp. by BHC has been tested. 35. The experience gained in the application of the foot- or walk-through bath for sheep is given.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on sucking lice of African mammals. Part I. Revision of certain doubtful Linognathus species

The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

NUMERICAL STUDY CONCERNING THERMAL RESPONSES OF NANOFILMS UNDER THE THERMOMASS THEORY

he Thermomass theory is based on the relationship mass-energy of Einstein, i.e., the heat has mass-energy duality, behaving as energy in processes where its conversion occurs in another form of energy, and behaving as mass in heat transfer processes. The mathematical model stablished by the Thermomass model falls within the class of problems called models non-Fourier heat conduction. The present work aims to analyze the thermal responses provided by Thermomass theory of nanofilms submitted to a very fast heating process using two different heat sources (laser pulses). During the process of analysis, the equations are written in conservation law, put into dimensionless form and discretized in the way that a high-order TVD scheme is used on to provide accurate and reliable numerical simulations for obtaining the thermal responses predicted by the Thermomass model. The results show that the Thermomass theory predicted a heterogeneous temperature distribution with elevated temperature peaks. The thermal responses obtained from this model may prevent the thermal damage caused by technologies of the processing and manufacturing of elements based on high-power laser applications

New species of sucking lice from South African game

During the course of a study on Anoplura material in the Onderstepoort collection, several specimens of the genus Linognathus were found which seemed to be incorrectly classified. A comparison with the respective types confirmed the suspicion and showed that these forms represent five distinct and so far undescribed species. Furthermore, a new species of Haematopinus collected recently off Eland, is also described in this paper. The types of all six new species are in the Onderstepoort collection.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

A PROPOSED METHODOLOGY TO EVALUATE SPECIFIC APPLICATIONS OF EXTENDED SURFACES IN INDUSTRIAL EQUIPMENT

The concept of Passive Cooling fits into a number of technological options involving constructive elements, whereby the heat exchange area of a surface being cooled by a surrounding fluid medium occurs. Thus, the increase in area results in an increase in the surface heat dissipation rate for the refrigerant, inferring only a single cost, i.e. the construction cost. Among the available technical possibilities, the use of extended surfaces, known as fins, stands out. The present work focuses on the use of fins on three very common electrical devices in the industrial environment, which present a great need for cooling.They are: three-phase transformer, frequency inverter and induction electric motor. The study is dedicated to a theoretical evaluation of the use of the fin profiles used in these equipments, since the manufacturers do not make their design data available to the public. Thus, a methodology was developed for this evaluation, including comparison of the results between the original profiles of these equipments with an alternative profile of similar design. Within the process of calculating the heat dissipation rates by the fins, the axial temperature distribution profiles were numerically determined using the Finite Difference discretization method, together with the Gauss-Seidel iterative method for the resolution of the discretized equations. The computational code was developed using MatLab® software. The results of the present work attested to the proper use of the original profiles employed by the manufacturers

The protection of sheep against blowfly strike. V. The duration of protection of certain insecticides under field conditions

A large number of field trials under close supervision was conducted in the blowfly areas of the Karoo to investigate certain biological aspects of blowfly strike as well as the protection afforded to sheep by the insecticides Diazinon, Dieldrin, Aldrin and B.H.C. under natural conditions. (1) The biological factors rendering sheep susceptible to blowfly strike are reviewed. (2) Observations on the development of strikes in sheep treated with an insecticide as compared with unprotected animals are reported. (3) The larvicidal value of the compounds tested are discussed, as well as the factors influencing the duration of protection afforded by them. (4) Dusts and wettable powders gave longer protection than emulsions in sheep with clean and dry crutches, whereas emulsions and wettable powders gave better results in soiled sheep. (5) The protecting agent must be evenly distributed throughout the vulnerable areas of the fleece right down to skin level to ensure the maximum degree of protection. (6) No significant difference in duration and degree of protection was observed with quantities of between 0•45 and 2•85 gm. of the active ingredient per crutch region. This is probably due to this factor being overshadowed by others. (7) Insecticides gave better protection when applied to long wool than to short wool. The crutching of soiled breeches is discouraged, therefore. (8) Soiled crutches exercise an influence upon the uniformity of the application and, consequently, upon the duration and the degree of protection. This is particularly evident in the case of B.H.C. No significant differences could be detected between Diazinon, Dieldrin and Aldrin. (9) All insecticidal compounds afford a considerably shorter period of protection on young lambs than on adult sheep with an equal or even shorter length of wool. (10) The incidence of blowflies (fly population pressure) exercises the most significant influence upon duration of protection afforded by any of the insecticides. The relationship between fly population pressure and duration or protection follows the equation of a hyperbola. (11) The duration of protection afforded by Diazinon, Dieldrin and Aldrin showed no significant differences under equal conditions, whereas B.H.C. was markedly inferior. (12) The Mule's operation affords adequate protection as long as the incidence of flies is low and the wool fairly short. With higher fly population pressures the resistance of "muled" sheep to fly strike decreases rapidly.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Infections Involving Cardiac Implantable Electronic Devices

Infections of cardiac implantable electronic devices (CIEDs) are an emerging problem because of increasing implant rates and comorbidities. If undiagnosed and untreated, CIED infection is associated with high mortality. Following the new guidelines concerning the use of cardiac resynchronization therapy devices in patients with congestive heart failure,1 CIED implantation has grown further. Unfortunately, this trend has been accompanied by an increase in infection rate, probably due to an increase in comorbidities. A recent analysis of US data2 showed that infection rate grew from 1.61% in 1993 to 2.41% in 2008, possibly due to two factors: ageing of population and increased use of more complex devices. Several studies3,4 have found that the most important risk factors for infection are re-intervention, with device replacement increasing with ageing of the population, and use of dual and triple chamber devices having increased over the last several years

<i>Gaia</i> Data Release 1. Summary of the astrometric, photometric, and survey properties

Context. At about 1000 days after the launch of Gaia we present the first Gaia data release, Gaia DR1, consisting of astrometry and photometry for over 1 billion sources brighter than magnitude 20.7. Aims. A summary of Gaia DR1 is presented along with illustrations of the scientific quality of the data, followed by a discussion of the limitations due to the preliminary nature of this release. Methods. The raw data collected by Gaia during the first 14 months of the mission have been processed by the Gaia Data Processing and Analysis Consortium (DPAC) and turned into an astrometric and photometric catalogue. Results. Gaia DR1 consists of three components: a primary astrometric data set which contains the positions, parallaxes, and mean proper motions for about 2 million of the brightest stars in common with the HIPPARCOS and Tycho-2 catalogues – a realisation of the Tycho-Gaia Astrometric Solution (TGAS) – and a secondary astrometric data set containing the positions for an additional 1.1 billion sources. The second component is the photometric data set, consisting of mean G-band magnitudes for all sources. The G-band light curves and the characteristics of ∼3000 Cepheid and RR-Lyrae stars, observed at high cadence around the south ecliptic pole, form the third component. For the primary astrometric data set the typical uncertainty is about 0.3 mas for the positions and parallaxes, and about 1 mas yr−1 for the proper motions. A systematic component of ∼0.3 mas should be added to the parallax uncertainties. For the subset of ∼94 000 HIPPARCOS stars in the primary data set, the proper motions are much more precise at about 0.06 mas yr−1. For the secondary astrometric data set, the typical uncertainty of the positions is ∼10 mas. The median uncertainties on the mean G-band magnitudes range from the mmag level to ∼0.03 mag over the magnitude range 5 to 20.7. Conclusions. Gaia DR1 is an important milestone ahead of the next Gaia data release, which will feature five-parameter astrometry for all sources. Extensive validation shows that Gaia DR1 represents a major advance in the mapping of the heavens and the availability of basic stellar data that underpin observational astrophysics. Nevertheless, the very preliminary nature of this first Gaia data release does lead to a number of important limitations to the data quality which should be carefully considered before drawing conclusions from the data

Norwegian GPs' participation in multidisciplinary meetings: A register-based study from 2007

<p>Abstract</p> <p>Background</p> <p>An increasing number of patients with chronic disorders and a more complex health service demand greater interdisciplinary collaboration in Primary Health Care. The aim of this study was therefore to identify factors related to general practitioners (GPs), their list populations and practice municipalities associated with a high rate of GP participation in multidisciplinary meetings (MDMs).</p> <p>Methods</p> <p>A national cross-sectional register-based study of Norwegian general practice was conducted, including data on all GPs in the Regular GP Scheme in 2007 (N = 3179). GPs were grouped into quartiles based on the annual number of MDMs per patient on their list, and the groups were compared using one-way analysis of variance. Binary logistic regression was used to analyse associations between high rates of participation and characteristics of the GP, their list population and practice municipality.</p> <p>Results</p> <p>On average, GPs attended 30 MDMs per year. The majority of the meetings concerned patients in the age groups 20-59 years. Psychological disorders were the motivation for 53% of the meetings. In a multivariate logistic regression model, the following characteristics predicted a high rate of MDM attendance: younger age of the GP, with an OR of 1.6 (95% CI 1.2-2.1) for GPs < 45 years, a short patient list, with an OR of 4.9 (3.2-7.5) for list sizes below 800 compared to lists ≥ 1600, higher proportion of psychological diagnosis in consultations (OR3.4 (2.6-4.4)) and a high MDM proportion with elderly patients (OR 4.1 (3.3-5.4)). Practising in municipalities with less than 10,000 inhabitants (OR 3.7 (2.8-4.9)) and a high proportion of disability pensioners (OR 1.6 (1.2-2.2)) or patients receiving social assistance (OR 2.2 (1.7-2.8)) also predicted high rates of meetings.</p> <p>Conclusions</p> <p>Psychological problems including substance addiction gave grounds for the majority of MDMs. GPs with a high proportion of consultations with such problems also participated more frequently in MDMs. List size was negatively associated with the rate of MDMs, while a more disadvantaged list population was positively associated. Working in smaller organisational units seemed to facilitate cooperation between different professionals. There may be a generation shift towards more frequent participation in interdisciplinary work among younger GPs.</p