Phase Change Material In Hiking Boots Does Not Minimise .
Phase Change Material in Hiking Boots DoesNot Minimise the Risk of Cold InjuryIgor B. Mekjavic, Bojana Andlovec Korosec, Martin Tomsic, Petra GoljaDepartment of Automation, Biocybernetics and Robotics, Jozef Stefan Institute,Jamova 39, SI-1000, Ljubljana, SloveniaNova Gorica Polytechnic, Kostanjeviska cesta 16, Pristava, SI-5000 Nova Gorica, Sloveniaigor.mekjavic@ijs.siABSTRACTThe present study compared the thermal insulation properties of identical hiking boots, incorporating alayer of either Sympatex or a layer of Outlast Phase Change Material (PCM). PCM contains paraffinfilled microcapsules, which change their state of aggregation with temperature. During heating, PCMliquefies and absorbs a certain amount of energy. Conversely, during cooling PCM changes from a liquidto a solid state and releases thermal energy. Specifically, we evaluated whether PCM offers anysignificant protection against peripheral cooling and subsequent cold injury to the feet. Subjects (20 malesand 20 females) participated in three trials. In two of these trials they immersed their booted feet,wrapped in a thin plastic bag, in 30 C for 15 min, followed by 3 hrs in 15 C water. On one occasion theywore boots with a PCM layer (PCM), and on the other, identical boots, but without a PCM layer(Control). At regular intervals we monitored tympanic temperature (Tty), average skin temperature of thearm, chest, thigh and calf (Tsk), foot temperature (6 sites), and heat flux from the skin of the foot (6 sites).Thermal insulation of the boots was determined separately with a thermal foot manikin. There was nochange in Tty and Tsk during the three trials. There were no differences in any of the foot skintemperatures or heat flux measurements between the Outlast and Sympatex boots. The thermalinsulation of the boots was 0.167 m2K/W for the Sympatex and 0.163 m2K/W for the Outlast boot.Phase change material does not offer any significant improvement in thermal protection, and thus doesnot minimise the risk of cold injury.1.0 INTRODUCTIONThe present study compared the thermal insulation properties of hiking boots (Alpina d.d., Slovenia)containing a layer of either Sympatex or Outlast Phase Change Material (PCM). PCM containsparaffin filled microcapsules, which change their state of aggregation with changing temperature. In theprocess of being heated from a solid state, PCM liquefies and absorbs a certain amount of thermal energy.Conversely, during cooling, PCM changes from a liquid to a solid state and releases thermal energy. Wetherefore tested the hypothesis that the exothermal reaction of the phase change material during exposureto cold may provide better thermal insulation and thus offer greater protection against adverse cooling andcold injury of the feet.2.0 METHODSTwenty subjects (10 males and 10 females) participated in the study. The protocol of the study wasapproved by the National Ethics Review Committee (Republic of Slovenia).Mekjavic, I.B.; Andlovec Korosec, B.; Tomsic, M.; Golja, P. (2005) Phase Change Material in Hiking Boots Does Not Minimise the Riskof Cold Injury. In Prevention of Cold Injuries (pp. 8-1 – 8-4). Meeting Proceedings RTO-MP-HFM-126, Paper 8. Neuilly-sur-Seine,France: RTO. Available from: 268-1
Form ApprovedOMB No. 0704-0188Report Documentation PagePublic reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering andmaintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information,including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, ArlingtonVA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if itdoes not display a currently valid OMB control number.1. REPORT DATE2. REPORT TYPE01 MAY 2005N/A3. DATES COVERED-4. TITLE AND SUBTITLE5a. CONTRACT NUMBERPhase Change Material in Hiking Boots Does Not Minimise the Risk ofCold Injury5b. GRANT NUMBER5c. PROGRAM ELEMENT NUMBER6. AUTHOR(S)5d. PROJECT NUMBER5e. TASK NUMBER5f. WORK UNIT NUMBER7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)Department of Automation, Biocybernetics and Robotics, Jozef StefanInstitute, Jamova 39, SI-1000, Ljubljana, Slovenia9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)8. PERFORMING ORGANIZATIONREPORT NUMBER10. SPONSOR/MONITOR’S ACRONYM(S)11. SPONSOR/MONITOR’S REPORTNUMBER(S)12. DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release, distribution unlimited13. SUPPLEMENTARY NOTESSee also ADM001854, Prevention of Cold Injuries (Prevention des accidents dus au froid) ., The originaldocument contains color images.14. ABSTRACT15. SUBJECT TERMS16. SECURITY CLASSIFICATION OF:a. REPORTb. ABSTRACTc. THIS PAGEunclassifiedunclassifiedunclassified17. LIMITATION OFABSTRACT18. NUMBEROF PAGESUU419a. NAME OFRESPONSIBLE PERSONStandard Form 298 (Rev. 8-98)Prescribed by ANSI Std Z39-18
Phase Change Material in Hiking BootsDoes Not Minimise the Risk of Cold InjurySubjects participated in two trials separated by a minimum of 5 days. During each trial they wore the sameclothing, with the exception of the hiking boots (Alpina d.d., Ziri, Slovenia). In one trial, the bootsincorporated Outlast as the thermal insulative layer and in the other Sympatex . The study was a doubleblind study; namely both the experimenters and subjects were naïve regarding the boots tested. Theexternal appearance of the boots was identical. Approximately 30 minutes prior to each experiment, theboots were wrapped in a polyurethane bag and immersed in a bath of water maintained at 30 C. Prior todonning the boots, the subjects left foot was instrumented with temperature and heat flux transducers.Once instrumented, both booted feet were then placed in the separate thin polyurethane bags andimmersed to within 1 cm of the top of the boot in 30 C water for 20 minutes. Thereafter, the feet wereimmersed in a similar manner in bath of water maintained at 15 C.During the immersion we monitored skin temperature of the upper arm (lateral aspect), chest (midclavicular line, at the level of the 3rd intercostal), mid-thigh (anterior aspect), and mid-calf (lateral aspect)with YSI 401 thermistors (Yellow Springs Instruments, Yellow Springs, Ohio, USA). Heat flux and skintemperature (Tsk C) was monitored with Concept Engineering Heat Flux transducers at six sites on theleft foot: toe (bottom), arch, heel, top of toes, instep, lateral. All measurements were recorded at 1-minuteintervals. Skin temperature from the torso was recorded with a Biopac data acquisition system controlledby Acknowldege Software on a Macintosh computer. Foot skin temperatures were recorded with anAlmemo data acquisition system (Ahlborn Mess-und Reglungstechnik GmbH, Holzkirchen, Germany).Tympanic temperature (Tty C) was recorded every 30 minutes with an infrared thermometer (ThermoScanIRT 3020, Braun, Kronberg, Germany).The differences between the average regional skin temperatures and heat fluxes observed with the twoprototype hiking boots were compared with a one way repeated measures ANOVA over the time intervalof 21 to 200 min.3.0 RESULTSAverage unweighed Tsk (33.79 1.39 C versus 33.81 1.16 C) and Tty (36.73 0.17 C versus 36.75 0.13 C) were identical during the Sympatex or Outlast trials respectively. There were no statisticallysignificant differences in any of the foot Tsk (Fig. 1 and 2) or heat fluxes between the two boots containingSympatex or Outlast . Overall thermal insulations of the boots determined with a Thermal FootManikin were 0.167 m2K/W and 0.163 m2K/W for the Sympatex and Outlast boots, respectively. Thedifference was not significant.8-2RTO-MP-HFM-126
Phase Change Material in Hiking BootsDoes Not Minimise the Risk of Cold InjuryToe temperature ( C)3634Boot lining material:32OUTLAST SYMPATEX 302826242220010 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200Time (min)Figure 1: Average toe temperature during 30 minutes immersion in 30 C water, followed by3 hr immersion in 15 C water. Subjects wore hiking boots containing a layer ofeither Outlast Phase Change Material (thick line) or Sympatex (thin line).4038Boot lining material:36Heel temperature ( C)OUTLAST SYMPATEX 3432302826242220010 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200Time (min)Figure 2: Average heel temperature during 30 minutes immersion in 30 C water, followed by3 hr immersion in 15 C water. Subjects wore hiking boots containing a layer ofeither Outlast Phase Change Material (thick line) or Sympatex (thin line).RTO-MP-HFM-1268-3
Phase Change Material in Hiking BootsDoes Not Minimise the Risk of Cold Injury4.0 CONCLUSIONIn contrast to the reported benefits of incorporating PCM in cold protective clothing (Pause, 1998), ourfindings concur with those of Endrusick et al. (2000), namely that Outlast Phase Change Material doesnot improve the thermal insulation properties of hiking boots.ACKNOWLEDGEMENTSSupported, in part, by a Science for Security and Peace grant (project no. M2-0018) from the Ministry ofDefence (Republic of Slovenia), and by Alpina d.d. (Ziri, Slovenia).REFERENCES[1]Endrusick T.L., Santee W.R., Gonzalez R.R., Brennick J.R., Smith C.A. Effects of wearing footwearinsulated with phase change materials during moderate cold exposure. In Werner J., Hexamer M.,editors. Environmental Ergonomics IX; 2000; Dortmund: Shaker Verlag; 2000. p. 319-322.[2]Pause, B. Development of a new cold protective clothing with phase change material. In: Holmér, I.,Kuklane K., editors. Problems with cold work. Solna: Arbetslivsinstitutet, 1998. p. 99 – 100.8-4RTO-MP-HFM-126
IRT 3020, Braun, Kronberg, Germany). The differences between the average regional skin temperatures and heat fluxes observed with the two prototype hiking boots were compared with a one way repeated measures ANOVA over the time interval of 21 to 200 min. 3.0 RESULTS
A Cub Scout Hiking Adventure. 2 Overview of the Trekkers Hiking Program Purpose The Monterey Bay Trekkers hiking program is an opportunity for Cub Scouts and their families to explore local hiking trails and parks in Monterey, San Benito and Santa Cruz Counties. Through the Trekkers program, Cub
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wound 3 phase motors. Rotary Phase Converter A rotary phase converter, abbreviated RPC, is an electrical machine that produces three-phase electric power from single-phase electric power. This allows three phase loads to run using generator or utility-supplied single-phase electric power. A rotary phase converter may be built as a motor .
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The mission of the Riverside District's Cub Hiking Club is to provide more opportunities for EVERY Cub Scout to engage in the outdoors. What you need to know about the program: 1. The Cub Hiking Club meets on the second Saturday of each month. Upon completion of the hike, that Cub Scout will be eligible for a monthly segment patch. All .
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P90X CLASSIC Phase 1 23 Phase 2 24 Phase 3 25 P90X DOUBLES Phase 1 26 Phase 2 26 Phase 3 27 P90X LEAN Phase 1 28 Phase 2 29 Phase 3 30 TABLE OF CONTENTS Warning: Due to the physical nature of this program, Beachbody recommends that you get a complete physical examination from your physician before getting started. .
