Operator's reaction time prolongation induced by whole-body vibration

Uticaj vibracija celog tela na vreme reakcije analiziran je uz pomoć, za ovu svrhu napravljenog, probnog stola sa mehaničkim pobudnim uređajem. Ispitanici su izlagani uslovima bez vibracija i vibracijama učestanosti 1, 5, 20 i 50 Hz. Najkraća vremena reakcije, kako na zvučne tako i na vizuelne pobude, izmerena su u uslovima bez vibracija. Najštetniji uticaj je primećen u slučaju vibracija učestanosti 5 Hz, kada se prosečna vremena reakcije uvećavaju za 50 do 70 ms. Najkraća vremena reakcije izmerena su na počecima testova, a najduža na njihovim završecima. Produženje vremena reakcije sa proticanjem vremena testa je izraženije u slučaju zvučnih pobuda. Takođe, pod istim uslovima, izmerena vremena reakcije su duža u slučaju zvučne pobude u odnosu na vizuelnu pobudu (u proseku za 60 do 100 ms). U svim slučajevima, promena vrednosti standardne devijacije pratila je obrazac sličan obrascu promene srednjih vrednosti vremena reakcije.Influence of whole-body vibration on reaction times was studied on a specially developed rig, with the subjects being exposed to no vibration, and vibration frequencies of 1, 5, 20 and 50 Hz. The shortest reaction times for both, sound and visual stimuli were measured for no vibration of the seating platform. The most detrimental influence was observed at vibration frequency of 5 Hz, with reaction times typically increasing between 50 and 70 ms. The shortest reaction times were always measured at the beginning of tests and the longest at the end. The increases in reaction times with elapsed time were typically more pronounced when subjects were exposed to sound stimuli. Equally, under the same conditions, reaction times to sound stimuli were longer than to visual stimuli (by approx. 60 to 100 ms). In all cases, changes in standard deviation values follow the same pattern as average reaction times

Operator's reaction time prolongation induced by whole-body vibration

Uticaj vibracija celog tela na vreme reakcije analiziran je uz pomoć, za ovu svrhu napravljenog, probnog stola sa mehaničkim pobudnim uređajem. Ispitanici su izlagani uslovima bez vibracija i vibracijama učestanosti 1, 5, 20 i 50 Hz. Najkraća vremena reakcije, kako na zvučne tako i na vizuelne pobude, izmerena su u uslovima bez vibracija. Najštetniji uticaj je primećen u slučaju vibracija učestanosti 5 Hz, kada se prosečna vremena reakcije uvećavaju za 50 do 70 ms. Najkraća vremena reakcije izmerena su na počecima testova, a najduža na njihovim završecima. Produženje vremena reakcije sa proticanjem vremena testa je izraženije u slučaju zvučnih pobuda. Takođe, pod istim uslovima, izmerena vremena reakcije su duža u slučaju zvučne pobude u odnosu na vizuelnu pobudu (u proseku za 60 do 100 ms). U svim slučajevima, promena vrednosti standardne devijacije pratila je obrazac sličan obrascu promene srednjih vrednosti vremena reakcije.Influence of whole-body vibration on reaction times was studied on a specially developed rig, with the subjects being exposed to no vibration, and vibration frequencies of 1, 5, 20 and 50 Hz. The shortest reaction times for both, sound and visual stimuli were measured for no vibration of the seating platform. The most detrimental influence was observed at vibration frequency of 5 Hz, with reaction times typically increasing between 50 and 70 ms. The shortest reaction times were always measured at the beginning of tests and the longest at the end. The increases in reaction times with elapsed time were typically more pronounced when subjects were exposed to sound stimuli. Equally, under the same conditions, reaction times to sound stimuli were longer than to visual stimuli (by approx. 60 to 100 ms). In all cases, changes in standard deviation values follow the same pattern as average reaction times

Heat Dissipation from Stationary Passenger Car Brake Disc

This paper presents an experimental investigation of the heat dissipation from stationary brake discs concentrated on four disc designs: a ventilated disc with radial vanes, two types of ventilated discs with curved vanes (a non-drilled and cross-drilled disc), and a solid disc. The experiments were conducted on a purpose-built thermal spin rig and provided repeatable and accurate temperature measurement and reliable prediction of the total, convective and radiative heat dissipation coefficients The values obtained compare favourably with computational fluid dynamics results for the ventilated disc with radial vanes and solid disc, though the differences were somewhat pronounced for the ventilated disc. The speeds of the hot air rising above the disc are under 1 m/s, hence too low to experimentally validate. However, the use of a smoke generator and suitable probe was beneficial in qualitatively validating the flow patterns for all four disc designs Convective heat transfer coefficients increase with temperature, but the values are very low, typically between 3 W/(m(2)K) and 5 W/(m(2)K) for the disc designs and temperature range analysed. As expected, from the four designs studied, the disc with radial vanes has the highest convective heat dissipation coefficient and the solid disc the lowest, being about 30 % inferior. Convective heat dissipation coefficient for the discs with curved vanes was about 20 % lower than for the disc with radial vanes, with the cross-drilled design showing marginal improvement at higher temperatures

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

We use 1-D thermal history models and 3-D numerical experiments to study the impact of dynamic thermal disequilibrium and large temporal variations of normal and shear stresses on the initiation of plate tectonics. Previous models that explored plate tectonics initiation from a steady state, single plate mode of convection concluded that normal stresses govern the initiation of plate tectonics, which based on our 1-D model leads to plate yielding being more likely with increasing interior heat and planet mass for a depth-dependent Byerlee yield stress. Using 3-D spherical shell mantle convection models in an episodic regime allows us to explore larger temporal stress variations than can be addressed by considering plate failure from a steady state stagnant lid configuration. The episodic models show that an increase in convective mantle shear stress at the lithospheric base initiates plate failure, which leads with our 1-D model to plate yielding being less likely with increasing interior heat and planet mass. In this out-of-equilibrium and strongly time-dependent stress scenario, the onset of lithospheric overturn events cannot be explained by boundary layer thickening and normal stresses alone. Our results indicate that in order to understand the initiation of plate tectonics, one should consider the temporal variation of stresses and dynamic disequilibrium

Rhodium platings – experimental study

Modern rhodium plating solutions are based on either sulphate or phosphate. Although in theory there are four possible combinations, in practice only three different rhodium electrolytes are used. These are based on dilutions of rhodium sulphate or phosphate concentrates with added sulphuric or phosphoric acid. These processes are be discussed in this paper with a demonstration of Rh platings in the Slovenian firm Zlatarna Celje d.d

Effects of different antibiotics in the treatment of acute rhinosinusitis

Introduction: Sinusitis is an inflammation of the paranasal sinuses and it can be infectious, allergic or autoimmune. Acute rhinosinusitis commonly has viral origin and occurs as part of the upper respiratory tract infections. The most common pathogens are Streptococcus, Pneumococcus and Haemophilus influenzae. Some inflammations may start as viral, but develop into bacterial superinfection, i.e., subsequent colonization of the bacteria in 0.5-2% of cases. Viral sinusitis lasts for 7-10 days, whereas bacterial may take longer. The aim: The aim of this study was to compare three therapeutic protocols for the treatment of acute bacterial rhinosinusitis. Materials and Methods: A prospective clinical study was conducted at the Ear, Nose and Throat Clinic, Clinical Center Nis from October 2019 to January 2020, and it involved patients with acute bacterial rhinosinusitis in whom we compared the efficiency and safety of levofloxacin administration for five and 10 days with the efficiency of amoxicillin clavulanate treatment. The study included 62 patients with documented clinical and radiological symptoms. Results: Confirmation of bacterial etiology is not routinely performed in clinical practice since it requires antral puncture or endoscopic examination of the middle nasal meatus. Consequently, the choice of antibiotic therapy is empiric. In our study, we used levofloxacin for five (500 mg once a day) and 10 days (500 mg once a day) and amoxicillin-clavulanatefor 10 days (500 mg-125 mg three times a day), and the results showed no statistically significant difference in regard to the choice of antibiotics and the duration of therapy. Conclusion: The findings of this study suggest that a short course of antibiotic treatment has similar efficiency compared to a longer course of treatment of patients with uncomplicated acute bacterial sinusitis when treatment is indicated

The influence of thermal evolution in the magnetic protection of terrestrial planets

Magnetic protection of potentially habitable planets plays a central role in determining their actual habitability and/or the chances of detecting atmospheric biosignatures. Here we develop a thermal evolution model of potentially habitable Earth-like planets and super-Earths (SEs). Using up-to-date dynamo-scaling laws, we predict the properties of core dynamo magnetic fields and study the influence of thermal evolution on their properties. The level of magnetic protection of tidally locked and unlocked planets is estimated by combining simplified models of the planetary magnetosphere and a phenomenological description of the stellar wind. Thermal evolution introduces a strong dependence of magnetic protection on planetary mass and rotation rate. Tidally locked terrestrial planets with an Earth-like composition would have early dayside magnetopause distances between 1.5 and 4.0 Rp , larger than previously estimated. Unlocked planets with periods of rotation ~1 day are protected by magnetospheres extending between 3 and 8 Rp . Our results are robust in comparison with variations in planetary bulk composition and uncertainties in other critical model parameters. For illustration purposes, the thermal evolution and magnetic protection of the potentially habitable SEs GL 581d, GJ 667Cc, and HD 40307g were also studied. Assuming an Earth-like composition, we found that the dynamos of these planets are already extinct or close to being shut down. While GL 581d is the best protected, the protection of HD 40307g cannot be reliably estimated. GJ 667Cc, even under optimistic conditions, seems to be severely exposed to the stellar wind, and, under the conditions of our model, has probably suffered massive atmospheric losses

A design concept for radiation hardened RADFET readout system for space applications

Instruments for measuring the absorbed dose and dose rate under radiation exposure, known as radiation dosimeters, are indispensable in space missions. They are composed of radiation sensors that generate current or voltage response when exposed to ionizing radiation, and processing electronics for computing the absorbed dose and dose rate. Among a wide range of existing radiation sensors, the Radiation Sensitive Field Effect Transistors (RADFETs) have unique advantages for absorbed dose measurement, and a proven record of successful exploitation in space missions. It has been shown that the RADFETs may be also used for the dose rate monitoring. In that regard, we propose a unique design concept that supports the simultaneous operation of a single RADFET as absorbed dose and dose rate monitor. This enables to reduce the cost of implementation, since the need for other types of radiation sensors can be minimized or eliminated. For processing the RADFET's response we propose a readout system composed of analog signal conditioner (ASC) and a self-adaptive multiprocessing system-on-chip (MPSoC). The soft error rate of MPSoC is monitored in real time with embedded sensors, allowing the autonomous switching between three operating modes (high-performance, de-stress and fault-tolerant), according to the application requirements and radiation conditions

Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets

The current progress in the detection of terrestrial type exoplanets has opened a new avenue in the characterization of exoplanetary atmospheres and in the search for biosignatures of life with the upcoming ground-based and space missions. To specify the conditions favorable for the origin, development and sustainment of life as we know it in other worlds, we need to understand the nature of astrospheric, atmospheric and surface environments of exoplanets in habitable zones around G-K-M dwarfs including our young Sun. Global environment is formed by propagated disturbances from the planet-hosting stars in the form of stellar flares, coronal mass ejections, energetic particles, and winds collectively known as astrospheric space weather. Its characterization will help in understanding how an exoplanetary ecosystem interacts with its host star, as well as in the specification of the physical, chemical and biochemical conditions that can create favorable and/or detrimental conditions for planetary climate and habitability along with evolution of planetary internal dynamics over geological timescales. A key linkage of (astro) physical, chemical, and geological processes can only be understood in the framework of interdisciplinary studies with the incorporation of progress in heliophysics, astrophysics, planetary and Earth sciences. The assessment of the impacts of host stars on the climate and habitability of terrestrial (exo)planets will significantly expand the current definition of the habitable zone to the biogenic zone and provide new observational strategies for searching for signatures of life. The major goal of this paper is to describe and discuss the current status and recent progress in this interdisciplinary field and to provide a new roadmap for the future development of the emerging field of exoplanetary science and astrobiology.Comment: 206 pages, 24 figures, 1 table; Review paper. International Journal of Astrobiology (2019

The Rhyacophila fasciata Group in Europe: Rhyacophila fasciata Hagen 1859 and formerly synonymized species (Trichoptera: Rhyacophilidae), with new description of Rhyacophila fasciata and Rhyacophila septentrionis McLachlan 1865 (stat. prom.).

[EN] The presence and distribution of Rhyacophila fasciata Hagen 1859 in Europe were revised, based on bibliographic study, collection specimens, and new material collected in different countries. The status of formerly synonymized species, Rhyacophila ferruginea (Scopoli 1763) and Rhyacophila septentrionis McLachlan 1865 was also assessed. The type of R. ferruginea is missing, the taxon is still unidentified, and thus we propose Rhyacophila ferruginea as a nomen dubium. Morphological features and genetic evidence revealed that R. septentrionis differs from R. fasciata, so we propose to change its status to status resurrectus. We therefore include new descriptions of the different stages (larva, pupa, male, and female) of R. fasciata and of R. septentrionis, together with a molecular analysis based on mitochondrial cytochrome oxidase I (mtCOI) and ecological notes. The species R. coppai Oláh 2020 NEW SYNONYM and R. soreda Coppa & Oláh 2020 NEW SYNONYM are synonyms of R. sociata Navás 1916; the species R. kopasa Oláh & Coppa 2020 NEW SYNONYM and R. rova Oláh & Coppa 2020 NEW SYNONYM are synonyms of R. denticulata McLachlan 1879; the species R. matrensis Oláh & Szcz¿sny 2020 is probably a synonym of R. fasciata, so more study of this species is needed in order to confirm or deny that it is a valid species.[ES] Se ha revisado la presencia y distribución de Rhyacophila fasciata Hagen 1859 en Europa, basada en el estudio de la bibliografía, especímenes de colecciones y en nuevo material recolectado en diferentes países. Se evaluó asimismo el estado de las especies anteriormente sinonimizadas Rhyacophila ferruginea (Scopoli 1763) y Rhyacophila septentrionis McLachlan, 1865. El ejemplar tipo de R. ferruginea se ha perdido y el taxón permanece todavía sin identificar, por lo que proponemos Rhyacophila ferruginea como un nomen dubium. Las características morfológicas y las evidencias genéticas indican que R. septentrionis difiere de R. fasciata, por lo que proponemos un cambio de estatus a status resurrectus. Se incluyen nuevas descripciones de las distintas etapas (larva, pupa, machos y hembras) de R. fasciata y de R. septentrionis, junto con el análisis molecular del gen mitocondrial Citocromo Oxidasa subunidad I (COImt), y notas ecológicas. Las especies R. coppai Oláh 2020 NUEVO SINÓNIMO y R. soreda Coppa & Oláh 2020 NUEVO SINÓNIMO son sinónimos de R. sociata Navás 1916; las especies R. kopasa Oláh & Coppa 2020 NUEVO SINÓNIMO y R. rova Oláh & Coppa 2020 NUEVO SINÓNIMO son sinónimos de R. denticulata McLachlan 1879; la especie R. matrensis Oláh & Szcz¿sny 2020 es probablemente un sinónimo de R. fasciata, por lo que se necesita un estudio más detallado para confirmarla o rechazarla como especie válida.This research is a part of scientific project “DNA barcoding of Croatian faunal biodiversity” (IP-2016-06-9988) funded by the Croatian Science Foundation. The work of P. Chvojka was supported by the Ministry of Culture of the Czech Republic (DKRVO 2019-2023/5.I.b, National Museum, 00023272)