Spin forming tubular elbows Patent

Apparatus and method for spin forming tubular elbows with high strength, uniform thickness, and close tolerance

Lithium abundances in nearby FGK dwarf and subgiant stars: internal destruction, Galactic chemical evolution, and exoplanets

We derive atmospheric parameters and lithium abundances for 671 stars and include our measurements in a literature compilation of 1381 dwarf and subgiant stars. First, a "lithium desert" in the effective temperature (Teff) versus lithium abundance (A_Li) plane is observed such that no stars with Teff~6075 K and A_Li~1.8 are found. We speculate that most of the stars on the low A_Li side of the desert have experienced a short-lived period of severe surface lithium destruction as main-sequence or subgiant stars. Next, we search for differences in the lithium content of thin-disk and thick-disk stars, but we find that internal processes have erased from the stellar photospheres their possibly different histories of lithium enrichment. Nevertheless, we note that the maximum lithium abundance of thick-disk stars is nearly constant from [Fe/H]=-1.0 to -0.1, at a value that is similar to that measured in very metal-poor halo stars (A_Li~2.2). Finally, differences in the lithium abundance distribution of known planet-host stars relative to otherwise ordinary stars appear when restricting the samples to narrow ranges of Teff or mass, but they are fully explained by age and metallicity biases. We confirm the lack of a connection between low lithium abundance and planets. However, we find that no low A_Li planet-hosts are found in the desert Teff window. Provided that subtle sample biases are not responsible for this observation, this suggests that the presence of gas giant planets inhibit the mechanism responsible for the lithium desert.Comment: ApJ, in press. Complete Tables 1 and 3 are available upon reques

How sketches work: a cognitive theory for improved system design

Evidence is presented that in the early stages of design or composition the mental processes used by artists for visual invention require a different type of support from those used for visualising a nearly complete object. Most research into machine visualisation has as its goal the production of realistic images which simulate the light pattern presented to the retina by real objects. In contrast sketch attributes preserve the results of cognitive processing which can be used interactively to amplify visual thought. The traditional attributes of sketches include many types of indeterminacy which may reflect the artist's need to be "vague". Drawing on contemporary theories of visual cognition and neuroscience this study discusses in detail the evidence for the following functions which are better served by rough sketches than by the very realistic imagery favoured in machine visualising systems. 1. Sketches are intermediate representational types which facilitate the mental translation between descriptive and depictive modes of representing visual thought. 2. Sketch attributes exploit automatic processes of perceptual retrieval and object recognition to improve the availability of tacit knowledge for visual invention. 3. Sketches are percept-image hybrids. The incomplete physical attributes of sketches elicit and stabilise a stream of super-imposed mental images which amplify inventive thought. 4. By segregating and isolating meaningful components of visual experience, sketches may assist the user to attend selectively to a limited part of a visual task, freeing otherwise over-loaded cognitive resources for visual thought. 5. Sequences of sketches and sketching acts support the short term episodic memory for cognitive actions. This assists creativity, providing voluntary control over highly practised mental processes which can otherwise become stereotyped. An attempt is made to unite the five hypothetical functions. Drawing on the Baddeley and Hitch model of working memory, it is speculated that the five functions may be related to a limited capacity monitoring mechanism which makes tacit visual knowledge explicitly available for conscious control and manipulation. It is suggested that the resources available to the human brain for imagining nonexistent objects are a cultural adaptation of visual mechanisms which evolved in early hominids for responding to confusing or incomplete stimuli from immediately present objects and events. Sketches are cultural inventions which artificially mimic aspects of such stimuli in order to capture these shared resources for the different purpose of imagining objects which do not yet exist. Finally the implications of the theory for the design of improved machine systems is discussed. The untidy attributes of traditional sketches are revealed to include cultural inventions which serve subtle cognitive functions. However traditional media have many short-comings which it should be possible to correct with new technology. Existing machine systems for sketching tend to imitate nonselectively the media bound properties of sketches without regard to the functions they serve. This may prove to be a mistake. It is concluded that new system designs are needed in which meaningfully structured data and specialised imagery amplify without interference or replacement the impressive but limited creative resources of the visual brain

An investigation into factors impacting on exports from South Africa to the Southern African Development Community (SADC)

Manufacturers face vigorous competition in local and export markets and need to have a genuine competitive advantage in order to grow. The South African government has recognised the importance of developing national manufacturing capacity as a means of increasing employment and reducing poverty. To this end, the government provides substantial support to both the manufacturing and exporting sectors. The government also negotiated the Southern African Development Community (SADC) agreement which leverages competitive advantages for South African manufacturers exporting into the region. However, since the ratification of the SADC agreement in 2008, there has been no perceptible increase in export activity to the region when compared to other markets. This research study was conducted to determine why this is the case and what factors are influencing the process. A structured literature review was undertaken to encapsulate export barriers, the role of the South African government in the export process, and the SADC agreement. The findings of the reviewed literature form the basis of the survey that led to the compilation of the research primary data. The results indicate that export barriers do not pose a major obstacle to trade into the SADC region. The role that the South African government holds was less conclusive with some successes noted, but on the whole the impact is not meaningfully positive. The SADC agreement and the dynamics prevailing in the free trade area do have a positive impact on exports to the region. The level of awareness with regard to the government support initiatives appears to be low.RésuméLes fabricants font face à une vive concurrence sur les marchés locaux et d’exportation et ont besoin d’avoir un véritable avantage concurrentiel pour se développer. Le gouvernement sud-africain a reconnu l’importance de renforcer les capacités nationales de production comme un moyen d’accroître l’emploi et réduire la pauvreté . À cette fin, le gouvernement apporte un soutien important à la fois la fabrication et secteurs exportateurs. Le gouvernement a également négocié l’accord Southern African Development Community (SADC ), qui s’appuie sur des avantages concurrentiels pour les fabricants sud-africains exportateurs dans la région. Cependant , depuis la ratification de l’accord de la SADC en 2008 , il a eu aucune augmentation perceptible de l’activité d’exportation de la région par rapport à d’autres marchés. Cette étude a été menée afin de déterminer pourquoi c’est le cas et quels sont les facteurs qui influencent le processus . Une revue de la littérature structurée a été entreprise pour encapsuler les obstacles à l’exportation , le rôle du gouvernement sud-africain dans le processus d’exportation , et l’accord de la SADC . Les résultats de la littérature examinée forment la base de l’enquête qui a conduit à la compilation des données primaires de la recherche . Les résultats indiquent que les barrières à l’exportation ne constituent pas un obstacle majeur au commerce dans la région de la SADC . Le rôle que le gouvernement sud-africain détient était moins concluante avec quelques réussites constatées, mais dans l’ensemble l’impact n’est pas significative positive. L’accord de la SADC et la dynamique qui prévaut dans la zone de libre-échange ont un impact positif sur les exportations de la région . Le niveau de sensibilisation à l’égard des initiatives de soutien du gouvernement semble être faibl

Mesospheric Motions Over Bear Lake

Since February 1999, the Utah State University Bear Lake Observatory (41.9oN, 111.4oW) dynasonde has been configured to operate as an Imaging Doppler Interferometer (IDI). Imaging Doppler interferometry is one of a number of MF/HF radar techniques used to estimate mesospheric winds and dynamics. This paper presents results of the mesospheric (50 – 115 km) background wind, tides, and planetary waves as derived from analysis of IDI observations recorded between February 03, 1999 and February 21, 2000 at Bear Lake

Mitigation of Radiation Induced Pulmonary Vascular Injury by Delayed Treatment with Captopril

Background and Objective: A single dose of 10 Gy radiation to the thorax of rats results in decreased total lung angiotensin-converting enzyme (ACE) activity, pulmonary artery distensibility and distal vascular density while increasing pulmonary vascular resistance (PVR) at 2 months post-exposure. In this study, we evaluate the potential of a renin-angiotensin system (RAS) modulator, the ACE inhibitor captopril, to mitigate this pulmonary vascular damage. Methods: Rats exposed to 10 Gy thorax only irradiation and age-matched controls were studied 2 months after exposure, during the development of radiation pneumonitis. Rats were treated, either immediately or 2 weeks after radiation exposure, with two doses of the ACE inhibitor, captopril, dissolved in their drinking water. To determine pulmonary vascular responses, we measured pulmonary haemodynamics, lung ACE activity, pulmonary arterial distensibility and peripheral vessel density. Results: Captopril, given at a vasoactive, but not a lower dose, mitigated radiation-induced pulmonary vascular injury. More importantly, these beneficial effects were observed even if drug therapy was delayed for up to 2 weeks after exposure. Conclusions: Captopril resulted in a reduction in pulmonary vascular injury that supports its use as a radiomitigator after an unexpected radiological event such as a nuclear accident