Search results for "FS"
showing 10 items of 1992 documents
Valsts papīru spiestuve un naudas kaltuve (1919-1940): izveidošana, darbība un loma poligrāfijas nozarē Latvijā
2017
Valsts papīru spiestuve un naudas kaltuve tika izveidota 1919. gadā, lai nodrošinātu Latvijas valsti ar nepieciešamajiem vērtspapīriem. Maģistra darba mērķis ir izpētīt spiestuves darbību no 1919.-1940. gadam un aprakstīt līdz šim nepētītu Latvijas vēstures jautājumu. Maģistra darba pirmajā nodaļā apskatīti valsts pirmie vērtspapīru pasūtījumi, Valstspapīru spiestuves izveidošana un pirmie tās darbības gadi. Darba otrajā nodaļā apskatīti problēmjautājumi, kas saistīti ar spiestuves darbību laika posmā no 1921. gada līdz 1940. gadam. Trešajā nodaļā analizēta Valstspapīru spiestuves loma starp valsts un privātajām spiestuvēm. Darba rezultātā tika izpētīta un aprakstīta Valstspapīru spiestuves…
Prenatal androgen exposure modulates cellular and humoral immune function of black-headed gull chicks
2005
Avian eggs contain considerable amounts of maternal yolk androgens, which have been shown to beneficially influence the physiology and behaviour of the chick. As androgens may suppress immune functions, they may also entail costs for the chick. This is particularly relevant for colonial species, such as the black-headed gull (Larus ridibundus), in which the aggregation of large numbers of birds during the breeding season enhances the risk of infectious diseases for the hatching chick.To test the effect of maternal yolk androgens on the chick's immune function, we experimentally manipulated, in a field study, yolk androgen levels within the physiological range by in ovo injection of either a…
Total ionizing dose (TID) evaluation of magnetic tunnel junction (MTJ) current sensors
2015
Abstract The paper shows an experimental study to know the behaviour of tunnel magnetoresistive effect-based current sensors configured in a Wheatstone bridge in response to irradiation. In particular the sensitivity, hysteresis, output offset voltage and input resistance are discussed when the sensors are submitted to a total irradiation dose of 43 krad with 36 krad/h dose rate. The same electrical parameters were studied subsequently once the irradiated sensors were submitted to an 80 °C annealing process. The studied TMR sensors are applied in a switched-mode power converter for space application.
Numerical and analytical analysis of a monopile-supported offshore wind turbine under ship impacts
2021
Abstract Offshore wind turbines in the vicinity of ship traffic are exposed to increased risks of ship collisions. To better understand the impact mechanism, this paper evaluates the dynamic responses of a monopile-supported wind turbine under ship impacts, using both numerical and analytical methods. The nonlinear finite element method is applied during the numerical simulations, and the wind load effects, soil conditions, and rigid and deformable ship bows are considered. The analytical approach, originally developed based on the energy method, is extended here to address the damping effects of monopile-supported wind turbines. In the case study, the impacts are studied between a 4600-ton…
Offshore wind metadata management
2014
Offshore wind energy is gaining more and more attention from industry and research community due to its high potential in producing green energy and lowering price on electricity consumption. However, offshore wind is facing many challenges, and hence it is still expensive to install in large scale. It therefore needs to be considered from different aspects of technologies in order to overcome these challenges. One of the problems of the offshore wind is that information comes from different sources with diversity in types and format. Besides, there are existing wind databases that should be utilised in order to enrich the knowledge base of the wind domain. This paper describes an approach …
A comparative study on the dynamic response of three semisubmersible floating offshore wind turbines
2019
Abstract Currently, there is a great interest to globally develop offshore wind energy due to the greenhouse effect and energy crisis. Great efforts have been devoted to develop reliable floating offshore wind energy technology to exploit the wind energy resources in deep seas. This paper presents a comparative study of the dynamic response of three different semisubmersible floating wind turbine structures. All the three platforms support the same 5MW wind turbine. The platforms examined are: a V-shaped Semi, an OC4-DeepCwind Semi and a Braceless Semi at 200 m water depth. A dynamic analysis is carried out in order to calculate and compare the performance of these platforms. The comparison…
Active heave compensation of floating wind turbine installation using a catamaran construction vessel
2021
Abstract The application of floating wind turbines is limited by the high cost that increases with the water depth. Offshore installation and maintenance continue to consume a high percentage of the project budget. To improve the installation efficiency of the floating offshore wind turbine, a novel concept is proposed by the SFI MOVE project. Several wind turbine superstructure components are preassembled onshore and carried to the installation site by a catamaran construction vessel. Each assembly can then be installed using only one lift, and the concept is less sensitive to weather conditions. In this paper, a control algorithm of the proposed hydraulic active heave compensator system i…
On tool stirring action in friction stir welding of work hardenable aluminium alloys
2013
In the paper solid state bonding conditions obtained in friction stir welding (FSW) of AA5754-H111 butt joints are analysed, considering the so called zigzag line in the transverse section of the joints. A wide experimental campaign was carried out varying both tool advancing speed and tool rotational one. The effects of the process on the mechanical properties of the joint were highlighted and micro- and macro-observations were used in order to explain the reasons of the enhanced mechanical properties found for the welded material. Numerical results derived from a FEM model previously developed by the authors were utilised to point out the different mechanical and metallurgical behavior of…
Metal-support interaction and redox behavior of Pt(1 wt %)/Ce0.6Zr0.4O2
2006
The catalyst Pt(1 wt %)/Ce(0.6)Zr(0.4)O(2) is studied by CO-temperature programmed reduction (CO-TPR), isothermal oxygen storage complete capacity (OSCC), X-ray absorption spectroscopy (XAS) at the Pt L(III) edge, and in situ X-ray diffraction (in situ XRD), with the aim of elucidating the role of supported metal in CO oxidation by ceria-based three-way catalysts (TWC). The redox behavior of Pt(1 wt %)/Ce(0.6)Zr(0.4)O(2) is compared to that of bare ceria-zirconia. OSCC of redox-aged Pt/ceria-zirconia is twice that of bare ceria-zirconia, and the maximum of CO consumption occurs at a temperature about 300 K lower than redox-aged ceria-zirconia. XAS analysis allows one to evidence the formati…
X-ray absorption spectroscopy study of local dynamics and thermal expansion in ReO3
2015
The thermal expansion of polycrystalline ${\mathrm{ReO}}_{3}$ is studied in vacuum by x-ray diffraction from 300 to 600 K and by extended x-ray absorption fine structure (EXAFS) at the Re ${L}_{3}$ edge from 30 to 600 K. A detailed EXAFS analysis is presented up to the sixth coordination shell around Re. The crystal thermal expansion is weak throughout the explored range, negative below 100 K, positive from 150 to 500 K, and negative again above 500 K. The analysis of mean square relative displacements obtained by EXAFS and of mean square displacements available from x-ray and neutron diffraction measurements confirms the presence of significant static disorder in the investigated samples. …