The main objectives of this research were to numerically analyze the potential for seasonal wind power (WP), assess wind direction, and select the most effective wind turbine (WT) for installation at ...the research site. Wind data were collected half-hourly from a branch of the Tanzania Meteorological Authority nearest to the research site. The collected data were analyzed using a double-parameter Weibull distribution (WD) model, where the standard deviation (SD) method was used to fit the WD. The results revealed that the site experienced strong winds within the range of 4.5–7 m/s between the hours of 05:00 - 20:00, with the most likely seasonal wind speed (WS) ranging from 5–7 m/s, while the mean seasonal WS was 9.07–12.14 m/s. The highest possible wind energy density (wED) of 23.3 GWh/m2 at a hub height of 10 m occurred during winter, followed by spring, autumn, and summer, with 6.39, 6.32, and 3.33 GWh/m2, respectively. The annual wED was > 13.52 GWh/m2, with a typical month-to-month energy of 1.13 GWh/m2. Finally, the study concluded that the recommended WT model (POLARIS P62-1000) was the best choice for installation at the study site due to its sustainable WS and WP potential. Based on the findings of this research, which show that the site has sustainable seasonal wind resources, it is suggested that future wind research be carried out to extend the dataset to ensure the long-term seasonal wind pattern at the site. Doi: 10.28991/HIJ-2024-05-02-08 Full Text: PDF
Failures of the cranes’ structural parts unavoidably lead to serious damages or total collapses; these accidents are often followed by very high financial losses and possibly serious injuries or ...crane-related fatalities. The objective of this research was to identify the causes that led to the failure of the hammerhead tower crane (xl425C) counterjib. The crane is used for assembly works at the hydropower dam. The counterjib collapse resulted from a gusset plate failure and caused such significant damage of the whole crane structure that the crane was dismantled and removed from operation. The study of the accident includes: (1) Identification of the stress-state, where a FEM model is developed to provide a useful tool for studying stress analysis; (2) Laboratory investigations are conducted in order to define the chemical composition and mechanical properties of the material, the tensile properties, hardness, impact toughness, as well as the metallographic analyses. The analysis of the obtained results showed that the principal reasons behind the gusset plate failure originated from design and fabrication faults. The working stress was higher than the allowable one. Also, impact toughness was too low and the fabrication of welds was incorrect.
This volume contains the proceedings of the CIEM workshop on Tropical Geometry, held December 12-16, 2011, at the International Centre for Mathematical Meetings (CIEM), Castro Urdiales, Spain. ...Tropical geometry is a new and rapidly developing field of mathematics which has deep connections with various areas of mathematics and physics, such as algebraic geometry, symplectic geometry, complex analysis, dynamical systems, combinatorics, statistical physics, and string theory. As reflected by the content of this volume, this meeting was mainly focused on the geometric side of the tropical world with an emphasis on relations between tropical geometry, algebraic geometry, and combinatorics. This volume provides an overview of current trends concerning algebraic and combinatorial aspects of tropical geometry through eleven papers combining expository parts and development of modern techniques and tools.
Nasca society emerged at the beginning of the Early Intermediate Period (AD1-750) and flourished along the arid south coast of Peru into the Middle Horizon (AD750-1000). In this study, long- and ...short-term residential mobility, palaeodiet and stress experiences for individuals from the ceremonial centre Cahuachi (n=41) and cemeteries in the Las Trancas river valley (n=13) are reconstructed. Emphasis is placed on understanding the synergy of movement, diet, stress, and the social and physical landscapes in producing the biochemical record archived in the human body. Through oxygen-isotope analysis of human tissues and modern environmental waters, it was demonstrated that, although most individuals buried at Cahuachi came from the Southern Nasca Region middle valleys, many spent a portion of their lives in other parts of the Rio Grande de Nasca drainage. Within-lifetime relocation was assessed using strontium- and oxygen-isotope analysis of bone and enamel pairs for a subset of individuals (n=20). These analyses revealed that half of the individuals analyzed moved between childhood and adulthood. Carbon- and nitrogen-isotope analyses of bone and hair showed dietary change consistent with (semi-) permanent relocation and with local mobility in the months/years before death. Together, these analyses suggest that movement, whether associated with burial at Cahuachi, relocation and/or local mobility, likely played an important role in the engagement of Nasca people with their physical and social landscapes. Long-term average diet consisted of a mixed C3/C4 plant base with greater reliance on maize and consumption of lower trophic level meat and plant-derived protein. Sequential isotopic analysis of hair demonstrated that some individuals had stable or seasonally shifting diets, and that others exploited multiple production zones. Dietary patterns are interpreted to represent flexibility in food acquisition as a means of minimizing risk associated with environmental and social instability. Biogenic patterns of cortisol production were observed in sequential analyses of hair, enabling direct reconstruction of stress experiences. Combined sequential isotopic and cortisol data provided insight into the metabolic and physiological causes of individual stress experiences associated with dietary change and residential mobility. Keywords: bioarchaeology, residential mobility, palaeodiet, stress, stable isotope analysis, cortisol, hair, Nasca, Cahuachi, Peru
In de aanloop naar de Russische aanval op Oekraïne bleek de westerse afschrikkingsdiplomatie niet in staat om Vladimir Poetin van zijn genocidale oorlogsplannen te weerhouden. De NAVO moet hier ...lessen uit trekken en een nieuwe, overtuigende afschrikkingsstrategie optuigen. Want Oekraïne zal niet het einde zijn van de Russische expansiedrift. Tegelijk is Amerikaanse militaire steun aan Europa in de toekomst allerminst gegarandeerd.
75 jaar NAVO van de Wijdeven, Ivo
Atlantisch Perspectief,
01/2024, Volume:
48, Issue:
2
Journal Article
Al 75 jaar rekenen de Europese landen via de NAVO op bescherming door de Verenigde Staten. Het Noord-Atlantisch Verdrag had een wederzijds strategisch belang. Toch zijn er ook genoeg momenten geweest ...dat het binnen het bondgenootschap niet boterde. Maar ondanks verdeeldheid op tal van terreinen is er toch eensgezindheid over de noodzaak elkaars grondgebied gezamenlijk te verdedigen. Dat is misschien wel de grootste kracht van het bondgenootschap.
Op 29 maart 2004 ging een vurige wens in vervulling: na meer dan tien jaar van subtiel diplomatiek massage-werk achter de schermen en soms nauwelijks verholen ongeduld traden de Baltische landen ...Estland, Letland en Litouwen toe tot de NAVO. Hun streven om voor eens en altijd uit de verstikkende invloedssfeer van grote buur en voormalig bezetter Rusland te ontsnappen leek beloond. Dat werd op 24 februari 2022, de dag dat Rusland Oekraïne binnenviel, nog eens onderstreept. ‘Zonder NAVO-lidmaatschap was dit ook ons lot geweest,’ klinkt het vaak in de Baltische landen.
Een web aan allianties Sheikh, Haroon
Atlantisch Perspectief,
01/2024, Volume:
48, Issue:
2
Journal Article
Al 75 jaar is de NAVO het succesvolste en sterkste veiligheidsverband dat de geschiedenis ooit heeft voortgebracht. Maar een wereldorde ontstaat niet uit een enkel instituut. Deze is eerder de ...uitkomst van een geheel van overlappende instituties en verbanden die staten op verschillende manieren verbinden. Die geopolitieke lappendeken is nu volop in ontwikkeling.
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