The local heat transfer characteristics associated with mixed convective developing flow through a horizontal tube exposed to a uniform wall temperature boundary condition

DATA AVAILABILITY : Data will be made available on request.Extensive research has been conducted on the heat transfer characteristics related to the boundary conditions present in phase-change applications. However, there remains a fundamental gap in understanding the local heat transfer characteristics of mixed convective laminar flow exposed to a uniform wall temperature boundary condition. Furthermore, there is a disparity between numerical and experimental studies investigating this boundary condition. This study addresses these gaps by being the first to experimentally investigate the local heat transfer characteristics of developing laminar flow through a horizontal tube exposed to a uniform wall temperature boundary condition. A novel experimental setup was developed to measure the mean fluid temperatures along a 5 m-long copper tube with an inner diameter of 4.9 mm. While the local results indicated an increase in wall temperature along the test section, the average Nusselt numbers correlated well with literature, indicating that similar temperature trends existed in prior experimental studies. The local heat transfer characteristics for developing laminar uniform wall temperature flow were divided into four regions: (1) Free Convection Developing, (2) Free Convection Governing, (3) Sustained Free Convection, and (4) Diminishing Heat Transfer. Free convection effects were found to increase near the inlet of the tube and the associated secondary flow assisted the flow in becoming fully developed. However, due to the decreasing wall-fluid temperature differences, free convection effects could not be sustained, and heat transfer eventually diminished as the fluid temperatures approached the wall temperatures.The National Research Foundation, Stellenbosch University/University of Pretoria Solar Hub, and Research Development Programme at the University of Pretoria.https://www.elsevier.com/locate/ijtshj2024Mechanical and Aeronautical EngineeringSDG-09: Industry, innovation and infrastructur

Knowledge management and performance: developing a theoretical approach to knowledge workers’ productivity, and practical tools for managers

Issue: The number of knowledge workers continues to grow, but we know little about what factors will promote knowledge workers’ productivity. Problem for discussion: How can managers promote knowledge workers’ productivity? Purpose: To develop aspects of a theory to promote knowledge workers’ productivity. Method: Conceptual generalization. Findings: Seven propositions (a mini-theory) for knowledge workers’ productivity. Keywords: knowledge worker, productivity, theory. JEL Classification: M

Assessing human diet and movement in the Tongan maritime chiefdom using isotopic analyses.

The rise of stratified societies fundamentally influences the interactions between status, movement, and food. Using isotopic analyses, we assess differences in diet and mobility of individuals excavated from two burial mounds located at the `Atele burial site on Tongatapu, the main island of the Kingdom of Tonga (c. 500 - 150 BP). The first burial mound (To-At-1) was classified by some archaeologists as a commoner's mound while the second burial mound (To-At-2) was possibly used for interment of the chiefly class. In this study, stable isotope analyses of diet (δ13C, δ15N, and δ34S; n = 41) are used to asses paleodiet and 87Sr/86Sr ratios (n = 30) are analyzed to investigate individual mobility to test whether sex and social status affected these aspects of life. Our results show significant differences in diet between burial mounds and sexes. Those interred in To-At-2 displayed lower δ13C values, indicating they ate relatively more terrestrial plants (likely starchy vegetable staples) compared with To-At-1 individuals. Females displayed significantly lower δ15N values compared with males within the entire assemblage. No differences in δ34S values were observed between sexes or burial mound but it is possible that sea spray or volcanism may have affected these values. One individual displayed the strontium isotopic composition representative of a nonlocal immigrant (outside 2SD of the mean). This suggests the hegemonic control over interisland travel, may have prevented long-term access to the island by non-Tongans exemplifying the political and spiritual importance of the island of Tongatapu in the maritime chiefdom

Marchés, organisation commerciale: Interaction entre les marchés de production et de consommation du porc

[fre] Les cours du porc (classe III) constatés en 1975 et 1976 (33 semaines) sur les cinq marchés de vente aux enchères de Bretagne, et sur les places de Paris (MIN de Rungis), Nantes, Lille, Lyon, Toulouse, ont été soumis à une analyse statistique pour mettre en évidence les influences réciproques des marchés, l'amplitude relative des variations... Quelques explications des faits constatés sont proposées. [eng] Interaction of the pork production and consumption markets - Pork prices (class 111) noted in 1975-1976 (33 weeks) on the five auction markets in Brittany and in Paris (Rungis), Nantes, Lille, Lyons, Toulouse, have undergone statistical analysis to bring out the reciprocal influences of the markets, the extent of variations. Some explanations are proposed for the phenomena recorded.

VOYAGE EN REPUBLIQUE FEDERALE D'ALLEMAGNE CONSACRE A L'ETUDE DES STRUCTURES AGRAIRES ET AUX AMENAGEMENTS DE VILLAGES Compte rendu de mission (du 15 au 21 mars 1964)

National audience1 - Introduction : 1.1 Objectifs de la mission ; 1.2 Participants " ; 1.3 Organisation matérielle " 2 - Informations générales sur la République Fédérale Allemande et la Hesse 2.1 République Fédérale Allemande ; 2.2 Hesse ; 2.3 Le problème des réfugiés de l'Est ; 2.4 La loi verte - la politique agricole allemande 3 - Remembrement - Exploitations désenclavées : 3.1 Législation allemande sur le remembrement ; 3.2 Un exemple de remembrement : Reinundsachxen ; 3.3 Situation d'ensemble du remembrement en Hesse ; 3.4 Quelques exemples d'exploitations déconcentrées ; 3. 5 Parallèle entre les méthodes françaises et allemandes 4 - Boisement et aménagements forestiers : 4.1 Situation des forêts en Rép. Féd. Allemande et en Hesse ; 4.2 Acquisition des sols en vue du boisement. Etudes pédologiques ; 4.3 Choix des essences - Plantations ; 4.4 Données économiques 5 - Aménagements de villages : 5.1 Problèmes généraux ; 5.2 Un exemple d'aménagement réussi : Ronshaiisen 6 - Les organisations agricoles : 6.1 Les syndicats d'exploitants agricoles : Bauernverband 6.2 Les organisations économiques : Deutscher Raiffeisenverband ; 6.3 Les Chambres d'Agriculture : Landwirtshaftkammer 7 - Un exemple caractéristique de l'industrie lourde allemande V.W. - kswagen ; 7.1 Les dimensions de l'entreprise ; 7.2 L'usine de Kassel 8 - Conclusion

VOYAGE EN REPUBLIQUE FEDERALE D'ALLEMAGNE CONSACRE A L'ETUDE DES STRUCTURES AGRAIRES ET AUX AMENAGEMENTS DE VILLAGES Compte rendu de mission (du 15 au 21 mars 1964)

National audience1 - Introduction : 1.1 Objectifs de la mission ; 1.2 Participants " ; 1.3 Organisation matérielle " 2 - Informations générales sur la République Fédérale Allemande et la Hesse 2.1 République Fédérale Allemande ; 2.2 Hesse ; 2.3 Le problème des réfugiés de l'Est ; 2.4 La loi verte - la politique agricole allemande 3 - Remembrement - Exploitations désenclavées : 3.1 Législation allemande sur le remembrement ; 3.2 Un exemple de remembrement : Reinundsachxen ; 3.3 Situation d'ensemble du remembrement en Hesse ; 3.4 Quelques exemples d'exploitations déconcentrées ; 3. 5 Parallèle entre les méthodes françaises et allemandes 4 - Boisement et aménagements forestiers : 4.1 Situation des forêts en Rép. Féd. Allemande et en Hesse ; 4.2 Acquisition des sols en vue du boisement. Etudes pédologiques ; 4.3 Choix des essences - Plantations ; 4.4 Données économiques 5 - Aménagements de villages : 5.1 Problèmes généraux ; 5.2 Un exemple d'aménagement réussi : Ronshaiisen 6 - Les organisations agricoles : 6.1 Les syndicats d'exploitants agricoles : Bauernverband 6.2 Les organisations économiques : Deutscher Raiffeisenverband ; 6.3 Les Chambres d'Agriculture : Landwirtshaftkammer 7 - Un exemple caractéristique de l'industrie lourde allemande V.W. - kswagen ; 7.1 Les dimensions de l'entreprise ; 7.2 L'usine de Kassel 8 - Conclusion

Occupational eye protection using Augmented Reality: a proof of concept

Eyes can be exposed to very small and bright light sources during occupational time, such as LEDs, welding arcs and lasers. Such light sources produce an accident-generating glare. In addition, the blue part of their spectrum and their high radiance make the operator’s retina at risk for the blue-light hazard. Filters protecting workers eyes tend to make lose the perception of the environment and task, and coloured protective glasses prevent from visible laser hazards but impair seeing alignment spots. An Augmented Reality system was investigated as a widespread and low-cost way to protect the operator’s eyes without impairing environment perception. It is made using a Virtual Reality helmet holding a smartphone, whose camera replaces the operator’s eyes. Real-time image processing allows operators to work safely on LEDs in operation, welding arcs and lasers. The user can see what he/she is doing while avoiding occupational exposure and glare. With visual ergonomics in mind, this system proves to be a potentially useful type of personal protective equipment against such bright light sources. In addition, it offers the ability to detect very near infrared laser spots