| 1. |
- Alametsä, Jarmo, et al.
(författare)
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Age-related circulatory responses to whole body cooling: observations by ballistocardiographic EMFi sensors
- 2014
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Ingår i: Proceedings of Ambience 14&10i3m : Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland - Scientific Conference for Smart and Functional Textiles, Well-Being, Thermal Comfort in Clothing, Design, Thermal Manikins and Modellin, 7-9 September 2014, Tampere, Finland. - 2342-4540. - 9789521532696 ; 1
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Konferensbidrag (refereegranskat)abstract
- The purpose was to study age related changes in circulatory system via Ballistocardiography (BCG) by utilizing Electromechanical Film (EMFi) sensors by gradually changing the ambient temperature from a thermoneutral area to cold direction. ECG and BCG were recorded from a young person (23 years) and from an older person (78 years), both males. During the tests, brachium blood pressure (BP) and pulse signals were recorded from neck and ankle (with EMFi sensor strips). Thermal camera images were taken in order to find out temperature changes in whole body and limbs. Temporal durations and amplitudes of seat BCG:s components (systolic and diastolic) as well as from pulse signals from neck and ankle were calculated. Aortic pulse wave velocity (PWV) was obtained by utilizing the time between ECG’s R wave and maximum value of the ankle pulse signal. In both persons, the ankle pulse amplitude decreased when propagating to cold direction and increased in young person when returning to warmer ambient temperature. With young and old BCG:s systolic and diastolic temporal complexes remained stable, but systolic amplitudes increased in the older person (AHI 1.02 – 2.87, AIJ 0.7 – 2.66) as well as diastolic amplitudes (old; AKL 0.47 – 2.37). In the older person, PWV increased when moving to colder side. BP increased with a young person (from 95/64 to 132/75 mmHg), and with older person (from 125/68 to 176/101 mmHg) having a prominent rise in diastolic values during the cooling. The neck pulse wave amplitude AOP rise was modest with the younger person and had variation with the older person. Older person had also more intensive shivering compared to younger one. With the older person, the limbs stayed cold in thermal images when returning from cold to thermoneutral area. The present preliminary observations indicated clear age-related differences in the circulatory response to a mild whole-body thermal challenge.
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| 2. |
- Alametsä, Jarmo, et al.
(författare)
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Age‐related circulatory responses to whole body cooling: observations by heart rate variability
- 2015
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Ingår i: Finnish Journal of eHealth and eWelfare. - 1798-0798. ; 7:2-3, s. 57-64
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to study potential age ‐ related changes in the circulatory system via heart rate variability (HRV) by gradually lowering ambient temperature (0.2°C/min) from thermoneutral (32 C°) towards cold (18 C°). ECG was recorded from a young (31 years) and from an older subject (78 years), both males. During the tests, brachium blood pressure (BP) was recorded. During the cooling, BP increased in both subjects (young from 95/69 to 132/75 mmHg, old from 125/68 to 176/101 mmHg), the latter exhibiting a prominent rise in diastolic values after cooling. HRV parameters increased in both subjects during the cold exposure being modest in the younger subject as compared to the older one. Also, recovery from the cold in terms of HRV was faster in the younger subject. The present preliminary observations indicate that older age is coupled with altered HRV response to a mild whole‐body skin cooling.
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| 3. |
- Eggeling, Jakob, et al.
(författare)
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Validating an advanced smartphone application for thermal advising in cold environments
- 2023
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Ingår i: International Journal of Biometeorology. - 1432-1254. ; 67:12, s. 1957-1964
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Tidskriftsartikel (refereegranskat)abstract
- The ClimApp smartphone application was developed to merge meteorological forecast data with personal information for individualized and improved thermal warning during heat and cold stress and for indoor comfort in buildings. For cold environments, ClimApp predicts the personal thermal stress and strain by the use of the Insulation REQuired model that combines weather and personal physiological data with additional consideration of the Wind Chill index based on the local weather forecast. In this study, we validated the individualized ClimApp index relative to measurements and compared it with the Universal Temperature Climate Index (UTCI). To this aim, 55 participants (27 females) were exposed to at least 1 h in an outdoor environment of 10 °C or below (average 1.4 °C air temperature, 74.9% relative humidity, and 4.7 m/s air velocity) inputting their activity level and clothing insulation as instructed by ClimApp. The UTCI and ClimApp indices were calculated and compared to the participants' perceived thermal sensation. The ClimApp index root mean square deviation (RMSD) was below the standard deviation of the perceived thermal sensation which indicates a valid prediction and the UTCI RMSD was higher than the standard deviation which indicates an invalid prediction. The correlation of ClimApp and UTCI to the perceived thermal sensation was statistically significant for both models.
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| 4. |
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| 5. |
- Gao, Chuansi, et al.
(författare)
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Halk- och fallolyckor, friktionskrav och balansförmåga
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Syftet med detta projekt var att studera samspelet mellan friktion, balansförmåga och halkrisker, samt att ta fram designrekommendationer för friktionskrav och halksäkrare skor och underlag. Sex studier har utförts innefattande friktionsmätningar av skor på olika underlag och temperaturer, studier av stående balans och gång på ramp med justerbar lutning samt fokusgruppintervjuer. Resultaten visar att vid arbete i rumstemperatur på våta klinkergolv bör skosulor av polyuretan användas då de ger högre friktion, utomhus på isigt underlag bör skor med gummi eller latexsulor användas. Oavsett skosulans material och mönster hade alla testade skor utom de dubbade mycket låg friktion på is med vatten. Mjukare material på skosulor bör användas i kyla. Stående tester på plan eller lutande balansplatta med två ytmaterial, takpapp och halt underlag, visade att mer friktion utnyttjades då underlaget lutades. Både underlagets lutning och friktion påverkade balansförmågan. Alla förändringar var tydligare för det hala underlaget, låg friktion är en riskfaktor för att tappa balansen, inte bara vid gång utan också vid stående arbete. Intervjuerstudien visade att upplevda halkrisker var relaterade till hala och lutande underlag och/eller våta eller snöiga skor. Kriterier för en halkfri vintersko var flexibilitet, komfort, multifunktionalitet, ergonomiskt design, individuell anpassning, stabilitet och gångsäkerhet samt anpassning till arbetssituation. Samband mellan friktionskrav och halkrisk på en ramp med olika lutningsvinklar och ytmaterial visade att ju högre lutningsvinkel, dess högre halkrisk och högre friktionskrav vid gång nedåt på både torr och våt stålplåt. Vått underlag och högre grad av lutning bör undvikas. Ett linjärt förhållande har identifierats mellan friktionskrav och lutningsvinkel, där friktionskrav för olika lutningsvinklar kan förutsägas. Ny kunskap om prevention av halk- och fallolyckor, utformning av halksäkrare skor och arbetsplatser har erhållits i projektet.
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| 6. |
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| 7. |
- Gao, Chuansi, et al.
(författare)
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Using a walkway with adjustable inclination to measure and assess slip and fall risks
- 2014
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Ingår i: Proceedings of CIB W099 International Conference Achieving Sustainable Construction Health and Safety. - 9789176230053 ; , s. 118-124
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Konferensbidrag (refereegranskat)abstract
- Fall is the most common cause of serious work related accidents. Falls and related injuries not only cause suffering for individuals, but also means a high economic burden to industries and society. The objective of the study was to use a walkway with in-built force plate, adjustable inclination and surface to assess how risks of slips and falls vary due to inclination and friction of the walkway surface. A walkway was designed with adjustable slopes between 0 to 30 degrees. Subject walking tests were performed on dry and wet steel sheet surfaces in two walking directions (uphill and downhill) at three inclination angles (0, 5 and 10 degrees). 3D ground reaction forces while walking were recorded using the force plate. Required coefficient of friction (RCOF) was derived to determine slip and fall risks. The main finding of this study is that the RCOF during heel strike when walking downwards on the steel plate surface increases linearly as the inclination increases. The results contribute to the understanding of slipping and falling mechanisms and the prevention of slipping and falling accidents. When ramps or sloped surfaces are used in workplaces, slip resistance between footwear and the sloped surfaces should be improved.
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| 8. |
- Gao, Chuansi, et al.
(författare)
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Validation of standard ASTM F2732 and comparison with ISO 11079 with respect to comfort temperature ratings for cold protective clothing
- 2015
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Ingår i: Applied Ergonomics. - : Elsevier BV. - 1872-9126 .- 0003-6870. ; 46:Online 17 July 2014, s. 44-53
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Tidskriftsartikel (refereegranskat)abstract
- American standard ASTM F2732 estimates the lowest environmental temperature for thermal comfort for cold weather protective clothing. International standard ISO 11079 serves the same purpose but expresses cold stress in terms of required clothing insulation for a given cold climate. The objective of this study was to validate and compare the temperature ratings using human subject tests at two levels of metabolic rates (2 and 4 MET corresponding to 116.4 and 232.8 W/m(2)). Nine young and healthy male subjects participated in the cold exposure at 3.4 and -30.6 °C. The results showed that both standards predict similar temperature ratings for an intrinsic clothing insulation of 1.89 clo and for 2 MET activity. The predicted temperature rating for 2 MET activity is consistent with test subjects' thermophysiological responses, perceived thermal sensation and thermal comfort. For 4 MET activity, however, the whole body responses were on the cold side, particularly the responses of the extremities. ASTM F2732 is also limited due to its omission and simplification of three climatic variables (air velocity, radiant temperature and relative humidity) and exposure time in the cold which are of practical importance.
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| 9. |
- Gao, Chuansi, et al.
(författare)
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Whole body heat balance and local insulation required to prevent extremity cooling in extremely cold environments
- 2016
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Ingår i: 6th International Conference on the Physiology and Pharmacology of Temperature Regulation. ; , s. 165-165
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Konferensbidrag (refereegranskat)abstract
- IntroductionLocal cooling in winter conditions is a sensitive and early warning of whole body cooling. Previous studies showed that the equilibrium temperature for the 5th finger is strongly affected by both temperature and insulation. The international standard ISO 11079 is used to calculate clothing insulation required for the whole body based on heat balance equations. However, it does not provide possibility to determine required insulation for local protection. The European standard EN 511 has provided a simple example of the thermal insulation level required as a function of ambient air temperature at a wind speed below 0.5 m/s. The objective of this study was to investigate the relationship between glove insulation and finger temperature in an extremely cold condition.MethodsNine subjects participated in a climatic chamber (Ta -30.6 °C, Va 0.4 m/s). Hestra wind stopper fleece fabric gloves and thicker cross country ski mittens (727 g/m2) with micro fleece lining were used for four and five subjects, respectively. Cold protective clothing (Icl=1.89 clo, standard total insulation: 2.26 clo) was used for subjects walking at 232.8 W/m2 to provide whole body thermal comfort according to ASTM F2732. Results and conclusionsThe rectal temperature was relatively stable (37.4 - 37.7 °C) during walking (90 min). The mean little finger temperature reduced to 7.9 (SD 1.4) °C when wearing Hestra wind stopper fleece fabric gloves (0.95 clo), whereas the finger temperature reached 17.8 (1.2) °C when wearing thicker ski mittens (1.46 clo). The insulation of gloves is required to be approximately about the standard total insulation of the ensemble (2.26 clo) to maintain thermal equilibrium of the finger (33 °C). The relationship (Iglove = 0.0522 * Tfinger + 0.5347) between finger temperature (°C) and glove insulation (clo) is established to estimate glove insulation required in this extremely cold environment.
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