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Tytuł:
From palaeosols to carbonate mounds: facies and environments of the middle Frasnian platform in Belgium
Autorzy:
Silva da, A. C.
Boulvain, F.
Powiązania:
https://bibliotekanauki.pl/articles/2058840.pdf
Data publikacji:
2004
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Belgium
middle Frasnian
carbonate platform
palaeogeography
facies
carbonate mounds
Opis:
This paper provides a synthetic sedimentological overview of themiddle Frasnian carbonate platform of Belgium and associated carbonate mounds. Carbonate mounds started usually in a relatively deep, quiet subphotic environment with a crinoid-coral-sponge assemblage, then reached the fair-weather wave base and the euphotic zone with an algal-microbial facies. The upper parts of themounds are characterised by lateral facies differentiation with the algal-microbial facies protecting a central sedimentation area with a dendroid stromatoporoids facies and fenestral limestone. The lateral facies reflect different kinds of input of reworked mound material in the proximal area, from transported fine-grained sediment to coarse-grained fossil debris. On the platform, environments range from the outer zone (crinoidal facies) to stromatoporoid-dominated biostromes and to the lagoonal area of the inner zones (subtidal facies with Amphipora floatstone, algal packstone, intertidal mudstone and laminated peloidal packstone and palaeosols). These facies are stacked in metre-scale shallowing-upward cycles. The larger scale sequential organisation corresponds to transgressions and regressions, whose cycles are responsible for differentiating a lower open-marine biostrome dominated unit from an upper lagoonal unit. The last regression- transgression cycle, responsible for the platform-scale development of lagoonal facies, can be correlated with an atoll-stage evolution of the carbonate mounds belonging to the Lion Member.
Źródło:
Geological Quarterly; 2004, 48, 3; 253--266
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new report on Hesperomyces coleomegillae (Ascomycota, Laboulbeniales) parasitism of Coleomegilla maculata (Coleoptera, Coccinellidae) in Brazil
Autorzy:
Inacio, C.A.
de Paulo, H.H.
Almeida, J.D.
Rembinski, J.
Menezes, E.L.A.
Silva, A.C.
Powiązania:
https://bibliotekanauki.pl/articles/2196347.pdf
Data publikacji:
2019-04-18
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
Hesperomyces
Ascomycota
Laboulbeniales
Coleomegilla maculata
Coleoptera
Coccinellidae
parasitism
host-parasite interaction
tropical fungi
Brazil
Opis:
For the first time, the genus Hesperomyces has been reported to infect Coleomegilla maculata in laboratory mass rearing in Brazil. Thalli were found growing on several parts of this ladybird species, including the head, elytra, legs, and abdomen. Infested adults died after 60 days.
Źródło:
Acta Mycologica; 2019, 54, 1; 1117
0001-625X
2353-074X
Pojawia się w:
Acta Mycologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High speed machining of aluminium gear box without temperature stabilization
Szybka obróbka aluminiowych obudów skrzyń biegów bez stabilizacji temperaturowej
Autorzy:
Silva, A.
Mateus, C.
Węgrzyn, T.
Miros, M.
Powiązania:
https://bibliotekanauki.pl/articles/374817.pdf
Data publikacji:
2010
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
stop aluminium
stabilność wymiarowa
obróbka szybkościowa
aluminium alloy
dimensional stability
high speed machining
Opis:
At the present time both clutch and mechanism housings, which are the main components from automotive gear boxes, are made of special aluminium alloys. These alloys are extremely light when compared with steel, making them a perfect choice to mitigate the cars weight and machining costs. Nonetheless they possess a high thermal expansion coefficient, which can be considered a major disadvantage since it makes necessary to pay extraordinary attention to dimensional variations during the production cycle due to temperature deviations. High speed machining of precision components made of aluminium requests thus their temperature to become previously stable. This procedure is the only way to force dimensions to stay inside its tolerance intervals. The main purpose of the present work was to assess the possibility to avoid the use of special ovens to make the clutch housing temperature become stable prior to machining. The dimensional stabilization of 40 sample parts, pre-heated at three temperature levels, was accomplished through the use of this system. The achieved results were made possible by analysing the part's temperature at the machine's entrance, the machine's interior temperature, 35 measured dimensions and their tolerance intervals as well as the average temperature deviations of each of the five considered batches. By analysing the obtained results in detail it was possible to determine which dimensions show high sensitiveness to temperature (high correlation between dimension's variation and temperature). Among these dimensions we can point out the ones related with depth, since they display the highest deviations due to temperature. Being a work with practical application it was possible to confirm the benefit of using this methodology by achieving significant enhancements on production efficiency, energy savings and reduction on maintenance costs, through the application of small adjustments to the machining sequence and by adopting a systematic tuning of certain dimensions.
Obecnie zarówno sprzęgło, jak i mechanizm przekładniowy, które są głównymi komponentami skrzyń biegów, umieszczone są w obudowie wykonanej ze specjalnych stopów aluminium. Stopy te są znacznie lżejsze w porównaniu ze stalą, powoduje to że są one doskonałym wyborem, by zmniejszyć wagę samochodów oraz 58 A.P. Silva, C.S. Mateus,, T. Wegrzyn, M. Miros koszty produkcji. Niemniej jednak materiały te posiadają wysoki współczynnik rozszerzalności cieplnej, który może zostać uznany ich główna wadą. Powoduje to że koniecznym stało się zwracanie dużej uwagi na utrzymanie wariantów wymiarowych podczas obróbki charakteryzującej się zmianami temperatury. Wysoka szybkość obróbki precyzyjnych komponentów wykonanych z aluminium spowodowała konieczność wcześniejszego ich podgrzewania w celu uniknięcia zmian temperatury podczas obróbki. Takie zabieg jest jedynym sposobem, aby zachować odpowiednią tolerancję wymiarową. Głównym celem niniejszej pracy była ocena możliwości, uniknięcia użycia specjalnych pieców wstępnie podgrzewających elementy przed obróbką w celu zapewnienia stabilizacji termicznej podczas obróbki. W pracy przeanalizowano możliwość zastosowania specjalnych komór z natryskowym systemem chłodzenia olejowego. Analiza osiągniętych wyników była możliwa poprzez pomiar temperatur na wejściu do maszyny oraz w jej wnętrzu. Pomiary przeprowadzono dla 35 próbek, których wymiary oraz tolerancję mierzono. Szczegółowa analiza pozwoliła stwierdzić, które z wymiarów wykazują się dużą wrażliwością na zmiany temperatury (wysoka korelacja między odmianą wymiaru i temperaturą). Pomiędzy wytypowanymi wymiarami najwrażliwszymi okazały się wymiary związane z głębokością. Uzyskane wyniki pozwoliły potwierdzić korzyści z używania opracowanej metody. Metoda ta pozwala na znaczne oszczędności energii oraz zwiększenie efektywności produkcji.
Źródło:
Transport Problems; 2010, 5, 3; 57-66
1896-0596
2300-861X
Pojawia się w:
Transport Problems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anthropometric indicators of obesity in policemen: A systematic review of observational studies
Autorzy:
Da Silva, Franciele C.
Hernandez, Salma S.
Gonçalves, Elizandra
Arancibia, Beatriz A.
Da Silva Castro, Thiago L.
Da Silva, Rudney
Powiązania:
https://bibliotekanauki.pl/articles/2178909.pdf
Data publikacji:
2014-12-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
obesity
police
systematic review
observational study
Opis:
The aim of this paper was to summarize scientific literature on obesity in policemen through a systematic review of observational studies. For this purpose the following electronic databases were selected: Medline by Pubmed, CINAHL, and Scopus; and a manual search of the referenced studies concerning this topic was performed. There were no restrictions with respect to the year or language of the publication. Twenty-three studies were identified and 9 articles, considered as potentially relevant, were included. The labor time, shift and career progression promoted changes in body composition. Most of the policemen taking part in the studies included in this paper were overweight (BMI: 25.2–29.3), obese (body fat ≥ 25%), had increased waist (90.4–102 cm) and abdominal perimeters (18.9–90.5 cm), and had a higher risk of chronic disease, which is associated with depression and stress development. Interventional studies are needed for the purpose of proposing preventive and rehabilitation programs, which would result in providing physical and mental well-being, improvement of life quality and, especially, prevention of obesity related to police work.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2014, 27, 6; 891-901
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
First record of mites associated with lima bean (Phaseolus lunatus L.)
Autorzy:
Neto, A.V.G.
Silva, P.R.R.
Silva, J.D.C.
Dos Santos, M.F.
Da Silva Melo, J.W.
De Franca, S.M.
Powiązania:
https://bibliotekanauki.pl/articles/2084632.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Tetranychidae
pest mites
legumes
Opis:
Pest mites of the family Tetranychidae are commonly reported in several legumes. However, reports of their occurrence in lima beans are insipient, especially in Brazil. The objective of this research was to record the occurrence of mites in lima bean plants and to describe their damage in this Fabaceae. Tetranychus neocaledonicus André and Mononychellus planki McGregor were found in lima bean plants, Phaseolus lunatus (Fabaceae or Leguminosae). The lima bean plants, when infested by these mites, initially exhibit small whitish spots in the leaflets, which with increasing population density rapidly evolve into chlorotic patches, followed by silvering, and may dry out and fall due to their overfeeding. The extent of the damage caused to lima bean plants and the adaptability of the mite to warm and dry conditions indicate that T. neocaledonicus has greater potential as a lima bean pest than M. planki in northeastern Brazil. This is the first record of these mites associated with P. lunatus.
Źródło:
Journal of Plant Protection Research; 2019, 59, 3; 418-422
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selectivity of diphenyl-ether herbicide with postemergence applications in chickpea
Autorzy:
Silva, L.G.B.
Da Silva Araujo, L.
Goncalves, D.J.
Souza Valente, M.
Da Silva, A.R.
Nascimento, W.M.
Ribeiro da Cunha, P.C.
Powiązania:
https://bibliotekanauki.pl/articles/2084719.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cicer arietinum
diphenyl-ether herbicides
weeds
Opis:
There are few reports in literature about the selectivity of postemergence application of herbicides for the control of eudicotyledon weeds (broadleaf) in chickpea. For this reason, the aim of this study was to investigate the selectivity of diphenyl-ether herbicides in chickpea influenced by the herbicides and application rates. A field experiment was conducted from February to June 2017 in Urutaí, state of Goiás, Brazil. Cultivar BRS Aleppo was used in the experiment. The experiment was set up in a randomized block design with 2 × 3 + 1 factorial arrangement and three replications. The first factor was herbicides (fomesafen and lactofen) with the second factor being herbicide rate (50, 75, and 100% of referenced rate) plus an untreated check as a comparison. The applied rates of herbicides were 250 and 180 g ⋅ ha–1 of fomesafen and lactofen, respectively. The selectivity of herbicides was evaluated according to agronomic characteristics (plant population, height, dry matter, number of pods per plant and 100-grain weight) and yields. Both herbicides, regardless of dosage, were selective in chickpea cultivation, even exhibiting leaf necrosis symptoms with visible injuries below 20% with no effect on yield.
Źródło:
Journal of Plant Protection Research; 2019, 59, 3; 350-354
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infinite ergodic index $ℤ^d$ -actions in infinite measure
Autorzy:
Muehlegger, E.
Raich, A.
Silva, C.
Touloumtzis, M.
Narasimhan, B.
Zhao, W.
Powiązania:
https://bibliotekanauki.pl/articles/1396029.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
We construct infinite measure preserving and nonsingular rank one $ℤ^d$-actions. The first example is ergodic infinite measure preserving but with nonergodic, infinite conservative index, basis transformations; in this case we exhibit sets of increasing finite and infinite measure which are properly exhaustive and weakly wandering. The next examples are staircase rank one infinite measure preserving $ℤ^d$-actions; for these we show that the individual basis transformations have conservative ergodic Cartesian products of all orders, hence infinite ergodic index. We generalize this example to obtain a stronger condition called power weakly mixing. The last examples are nonsingular $ℤ^d$-actions for each Krieger ratio set type with individual basis transformations with similar properties.
Źródło:
Colloquium Mathematicum; 1999, 82, 2; 167-190
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radiation processing of detergents and possible environmental benefits
Autorzy:
Borrely, S. I.
Romanelli, M. F.
Pereira, M. C. C.
da Silva, G. P.
Mesquita, L. C. A.
de Moraes, M. C. F.
Powiązania:
https://bibliotekanauki.pl/articles/148020.pdf
Data publikacji:
2009
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
EB irradiadion
anionic surfactants
effluent
Vibrio fischeri
Daphnia similis
Opis:
Detergents at waters inducing negative changes for biological degradability and water general quality. Some authors have evidenced a considerable amount of anionic surfactant and toxic effects into natural water and effluents related to detergents. The objective of the study was to apply electron irradiation for reducing toxicity, and for degradation of surfactants. To quantify surfactant LAS determination as MBAS (metylene blue active substances) was applied. The capacity of radiation to reduce surfactants was evidenced for real effluent and for water solution containing sodium dodecyl sulfate, linear alkylbenzene sulfonate (LAS), separately. An electron beam accelerator (EBA) 1.5 MeV was the radiation source. Anionic surfactant solutions as well as real effluents resulted in less toxic samples after irradiation. Toxicity was evaluated for Vibrio fischeri and Daphnia similis. An important decline of total anionic surfactant was observed after irradiation to doses: 6.0 kGy and 20 kGy (surfactant in water solutions and effluents, respectively). To conclude, EBA irradiations accounted for 88% to 96% less toxic surfactants solutions and effluents and 68% to 96% for MBAS compounds decomposition.
Źródło:
Nukleonika; 2009, 54, 2; 61-64
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development and production of radioactive sources used for cancer treatment in Brazil
Autorzy:
Rostelato, M. E. C. M.
Rela, P. R.
Zeituni, C. A.
Feher, A.
Manzoli, J. E.
Moura, J. A.
Moura, E. S.
Silva, C. P. G.
Powiązania:
https://bibliotekanauki.pl/articles/148305.pdf
Data publikacji:
2008
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
radioactive sources production
iodine-125 seeds
iridium-192 wires
brachytherapy
cancer treatment
Opis:
The number of cancer patients in Brazil is increasing and part of the patients are submitted to brachytherapy treatment using iridium-192 wire and iodine-125 radioactive seeds. The Nuclear Energy Research Institute established a programme to produce iridium-192 wire and iodine-125 radioactive seeds. With the purpose of settling a laboratory for iridium-192 sources production, a wire activation method was developed and a hot cell for the wire manipulation, quality assurance and packaging was built. The iodine-125 seeds consist of a welded titanium capsule containing iodine-125 adsorbed onto a silver rod. Concerning the setup of the local production, the following activities were carried out: superficial treatment of the silver rod, development of a process to absorb the iodine in the silver rod, welding methodology to seal the seeds, leakage and contamination test and source activity measurement.
Źródło:
Nukleonika; 2008, 53, suppl. 2; 99-103
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined Analyses of Ion Beam Synthesized Layers in Porous Silicon
Autorzy:
Ramos, A. R.
Pászti, F.
Horváth, Z. E.
Vázsonyi, É.
Conde, O.
da Silva, M. F.
da Silva, M. R.
Soares, J. C.
Powiązania:
https://bibliotekanauki.pl/articles/2028988.pdf
Data publikacji:
2001-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.10.-i
61.18.Bn
61.43.Gt
68.55.Ln
Opis:
High dose ion implantation was used to form polycrystalline silicide films on porous silicon with different native concentrations of light impurities (C and O). Porous silicon layers severalμm thick were implanted with 170 keV Cr$\text{}^{+}$ ions to fluences of 3×10$\text{}^{17}$ ions/cm$\text{}^{2}$ both at room temperature and 450ºC. Similar samples were implanted with 100 keV Co$\text{}^{+}$ ions to fluences of 2×10$\text{}^{17}$ ions/cm$\text{}^{2}$ at room temperature, 350ºC, and 450ºC. The formed silicide compounds were studied by Rutherford backscattering spectrometry, elastic recoil detection, glancing incidence X-ray diffraction, and four point-probe sheet resistance measurements. Selected Co implanted samples were analysed by cross-section transmission electron microscopy. Results show that the light impurities were partially expelled from the forming silicide layer. Combining cross-section transmission electron microscopy with ion beam methods it was possible to show that, in the implanted region, the porous structure collapses and densifies during implantation, but the underlying porous silicon remains intact. The layer structure, as well as the quality and type of the formed silicide, were found to depend on the original impurity level, implantation temperature, and annealing.
Źródło:
Acta Physica Polonica A; 2001, 100, 5; 773-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A note on the computation of ordered supported non-dominated solutions in the bi-criteria minimum spanning tree problems
Autorzy:
Silva, C. G.
Cli'maco, J. C. N.
Powiązania:
https://bibliotekanauki.pl/articles/308580.pdf
Data publikacji:
2007
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
minimum spanning tree
supported non-dominated solutions
combinatorial problems
Opis:
This paper presents a new procedure for computing the set of supported non dominated solutions of bi-criteria minimum spanning tree problems in ordered manner. The procedure is based on the systematic detection of edges which must be replaced in one efficient solution to obtain the adjacent one, in the criteria space. This new approach avoids solving unnecessary problems and makes use of previous computations.
Źródło:
Journal of Telecommunications and Information Technology; 2007, 4; 11-15
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of the effects of recycling on process control
Autorzy:
Silva, Cássio R.A.
Panuci, Victor C.
Coutinho, Monica R.
Conceição, Wagner A.S.
Andrade, Cid M.G.
Powiązania:
https://bibliotekanauki.pl/articles/27315644.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
level control
control structure
decoupled tanks
cycle
Arduino
Opis:
The union of different devices in order to obtain a specific response for a process is commonly called a control system. For a control system, it is necessary to have one or more controllers. Among the most used in the industrial sector are the PID and PI controllers. Next to these controllers is the control software. Scilab is a good example of control software. It is characterized as free code software, with no cost for its acquisition, in addition to having a large computational power and integrated tools, such as Xcos, intended for modeling and simulation. For the union with Scilab, there is Arduino. Such a mixture can be used, for example, to control liquid levels in tanks. In this context, the present work aims to study the tank-level control system based on PID and PI controllers through the union between Scilab and Arduino. Phenomenological models were developed based on closed-loop control (feedback control system) of the process with two tanks not coupled with recycle. Furthermore, for comparison purposes, two approaches were used for each process: one considering the saturation of the manipulated variable and the other without the presence of such saturation. At first, there was a need to implement an anti-windup system. For tuning the controller parameters, the ISE method was used, executed through a programming code developed in Scilab. The parameters found for the two systems were tested on a made-up experimental bench. Therefore, using the block diagrams and the method here called “ISE method”, satisfactory values were obtained for the control parameters. These were ratified in the tests carried out in the experimental module. Level control was achieved with greater prominence for the PI controller since there is one less parameter to be tuned and processed by the system. This controller provided results close to the PID controller for cycles up to 50%. In general, the PI controller showed maximum response deviations smaller than the PID, such as deviations of 1.55 cm and 2.40 cm, respectively, for the case with 75% recycle. It was also clear the influence of the saturation of the manipulated variable on the system response, but not on the tuning of the controller parameterseters.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 2; 43--55
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion Behavior of FeAl and Fe3Al Based Fe-Al-C Alloys in Sulfuric Acid
Autorzy:
Silva, A. P.
Brito, P. P.
Martins, N.
Powiązania:
https://bibliotekanauki.pl/articles/2134209.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
iron aluminides
microstructure
mechanical properties
corrosion resistance
Opis:
Iron aluminides are iron-aluminum alloys that have excellent resistance to oxidation at high temperatures with low density, high resistance/weight ratio and a low manufacturing cost. Due to its characteristics, these alloys are presented as an option to replace stainless steels in certain applications. This works intends report the casting process and subsequent analyses involving microstructure, mechanical properties, and corrosion resistance of two Fe-Al-C alloys (Fe-11wt%Al and Fe-25wt%Al, containing 0.31-0.37%C), which were prepared in an induction furnace and poured in a permanent mold. Samples of these alloys were characterized and presented elevated hardness values of 37 HRC (alloy Fe-11wt%Al) and 49.6HRC (alloy Fe-25wt%Al) and microstructure with aluminides type Fe3Al and FeAl and also carbides type K. The Fe-11wt%Al alloy exhibited superior resistance to uniform corrosion, although both Fe-Al-C alloys exhibited significantly higher corrosion rates compared to a binary iron aluminide in 0.5M H2SO4 containing naturally dissolved oxygen.
Źródło:
Archives of Foundry Engineering; 2022, 22, 2; 77--82
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Relationship between performance, dry-land power and kinematics in master swimmers
Autorzy:
Espada, M. C.
Costa, M. J.
Costa, A. M.
Silva, A. J.
Barbosa, T. M.
Pereira, A. F.
Powiązania:
https://bibliotekanauki.pl/articles/307228.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pływanie
kinematyka
energia
master swimmers
kinematic
dry-land power
performance
Opis:
The purpose of the study was to analyze the relationships between sprint swimming performance, dry-land power, and kinematics in master swimmers. Twenty-two male master swimmers were separated in two groups based on their chronological age: (i) 30–39 years and; (ii) 40–49 years. Maximum dry-land power was determined through counter movement jump and 3 kg medicine ball throwing (Hmax and Tmax, respectively). Kinematic determinants of performance were measured during a maximal bout of 15, 25 and 50 m front crawl (T15, T25, T50). Stroke frequency (SF), stroke length (SL) and stroke index (SI) were calculated as kinematical aspects of the stroke. In the 30-39 group, SI25 was correlated to T25 (r = –0.76, p < 0.01, η2 = 0.96), the same was observed between SI50 and T50 (r = –0.83, p < 0.01, η2 = 0.96). Only SI50 was significantly correlated to T50 (r = –0.86, p < 0.01, η2 = 0.97) in the 40–49 years age cohort. In dryland power variables, Hmax and Tmax were only correlated in the younger master swimmers group (r = –0.87, p < 0.01, η2 = 0.97). There were no significant differences (p < 0.05) between younger (30–39 years) and older (40–49 years) swimmers groups in dry-land tests (Hmax 28.5 ± 5.9 vs. 26.5 ± 3.9 cm and Tmax 4.2 ± 1.0 vs. 4.2 ± 1.1 m). Our results suggest that swimming performance in younger master swimmers (30–39 years) seem more dependent on kinematic swimming variables than on strength parameters, which were most related to swimming performance in the older master swimmers (40–49 years).
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 2; 145-151
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Whole Body Postural Loading Simulation and Assessment Model for Workplace Analysis and Design
Autorzy:
Rebelo, F.
Da Silva, K. C.
Karwowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/90481.pdf
Data publikacji:
2012
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
simulation models
spinal loading
ergonomics
manual materials handling
work design
safety
Opis:
This study reports on the development and validation of a new computer model for simulating human postures at work, and assessing the reaction forces and bending moments in 43 human articulation joints. The proposed model estimates the intradiscal pressure in the vertebral column in response to external loading forces encountered during human interactions with work objects or processes. The model was implemented in a selfcontained interactive software package. The simulation results compare favorably with the reported experimental data, and provide reasonable confidence in the quality of the model. Its characteristics and its applications in evaluating physical task performance are also discussed.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2012, 18, 4; 509-519
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 35

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