Arduous Environments Research Articles

Stress Response to Winter Warfare Training: Potential Impact of Location.

Winter warfare training (WWT) is a critical component of military training that trains warfighters to operate effectively in extreme environments impacted by snow and mountainous terrain. These environmental factors can exacerbate the disruption to the hormone milieu associated with operating in multi-stressor settings. To date, there is limited research on the physiological responses and adaptations that occur in elite military populations training in arduous environments. The purpose of this study was to quantify hormone responses and adaptations in operators throughout WWT. Participants engaged in baseline laboratory metrics at their home station, Fort Carson, located in Colorado (CO) prior to WWT, for one week in Montana (MT) and one week in Alaska (AK). WWT periods were separated by approximately one month. Blood was collected upon wake at baseline (CO) and on the first and last day of WWT at each location (MT and AK). Plasma was analyzed for stress, metabolic, and growth-related hormones via enzyme-linked immunoassay (ELISA). Sleep quality was assessed via the Pittsburg Sleep Quality Index (PSQI) at baseline (CO) and on the first day of training in MT and AK. Cognitive function was evaluated using the Defense Automated Neurobehavioral Assessment (DANA) at baseline (CO) and on the first and last day of WWT in both MT and AK. Fourteen US Army operators in 10th Special Forces Group (SFG) Operational Detachment participated in winter warfare training (WWT; age: 31.5 years; 95%CI[28.1, 34.3]; height: 180.6 cm; 95%CI[177.3, 183.4]; weight: 87.4 kg.; 95%CI[80.6, 97.7]; body fat: 18.9%; 95%CI[13.7, 23.1]; male: n=13; female: n=1). Plasma adrenocorticotropic hormone (ACTH) levels increased from baseline (19.9 pg/mL; 95%CI[8.6, 24.2]) to pre-WWT (26.9 pg/mL; 95%CI [16.2, 37]; p=0.004), decreased from pre- (26.9 pg/mL; 95%CI [16.2, 37]) to post-WWT in MT (22.3 pg/mL; 95% CI [8, 23.7]; p=0.004;), and increased from pre- (25 pg/mL; 95%CI[ 28.4) to post-WWT (36.6 pg/mL; 95%CI [17.9, 48.9]) in AK (p=0.005). Plasma cortisol levels decreased from pre- (174 ng/mL; 95%CI[106.2, 233.6]) to post-WWT (94.5 ng/mL; 95%CI[54.8, 101.7]) in MT (p=0.001) and, conversely, increased from pre- (123.1 ng/mL; 95%CI[97.5, 143.9]) to post-WWT (162.8 ng/mL; 95%CI[128, 216.7]) in AK (p<0.001). Alterations in growth-related hormones (insulin-like growth factor 1 [IGF-1], insulin-like growth factor binding protein 3 [IGFBP-3], and sex hormone binding globulin [SHBG]) were observed throughout WWT (p<0.05). The Total Testosterone / Cortisol ratio (TT / CORT; molar ratio) was lower pre-WWT in MT (0.04; 95%CI[0.01,0.04) compared to baseline in CO (0.07; 95%CI[0.04, 0.07]; p=0.042). Triiodothyronine (T3) levels increased from pre- (101.7 ng/dL; 95%CI[93.7, 110.4]) to post-WWT (117.8 ng/dL; 95%CI[105.1, 129.4]) in MT (p=0.042). No differences in sleep quality were reported between locations (CO, MT, and AK). Alterations in cognitive function were exhibited between locations and during WWT in both MT and AK (p<0.05). Over the course of WWT, elite operators experienced alterations in stress, metabolic, and growth-related hormones, as well as cognitive performance. The increase in stress hormones (i.e., ACTH and cortisol) and reduction in cognitive performance following training in AK are suggestive of heightened physiological strain, despite similarities in physical workload, self-reported sleep quality, and access to nutrition. The variation in hormone levels documented between MT and AK may stem from differences in environmental factors, such as lower temperatures and harsh terrain. Further research is warranted to provide more information on the combined effects of military training in extreme environments on operator health and performance.

C-reactive protein (CRP) in high altitude Bolivian peri-urban adolescents varies by adiposity, current illness, height, socioeconomic status, sex, and menarcheal status: The potential benefits and costs of adipose reserves in arduous environments.

In non-industrialized and low-income populations, adipose stores can serve as a valuable buffer against harsh conditions such as seasonal food scarcity. However, these reserves may incur costs due to adipocytes' production of pro-inflammatory cytokines; inflammation is associated with increased risk for cardiometabolic diseases later in life. Life history theory posits that, especially in populations with high juvenile mortality, higher adiposity may nonetheless be advantageous if its benefits in early life outweigh its later costs. Relatively little is known about adolescents' C-reactive protein concentration (CRP; an inflammation biomarker) in such environments. We investigated CRP and its associations with several hypothesized predictors in adolescents in an economically diverse peri-urban Andean community. We measured CRP in dried blood spots and collected data on anthropometrics, illnesses, socioeconomic status (SES), and menarcheal status in 59 female and 40 male adolescents ("Alteños", 11.0-14.9 years old) with normal vital signs in El Alto, Bolivia (~4150 m amsl). We used Cole's LMS method to standardize all anthropometrics for sex and age, and principal components analysis to construct a "fat-factor" variable loading on these standardized z-scores. We used multiple linear regression to assess the influence of fat-factor and other likely predictors on CRP rank. Compared to a national Bolivian growth reference, Alteños were, on average, shorter and leaner; only 6% were classified as overweight and none were obese. Pre-menarche females were on average leaner than post-menarche females. The best-fitting model explained 24% of the variance in CRP rank. Significant predictors were fat-factor, SES, current illness for males and pre-menarche females, and z-height for females. Our results are consistent with a tradeoff between investments in growth versus immune functioning, as might be expected in an environment with limited resources and high pathogen exposure (e.g., soil-transmitted helminths, poor sanitation). Thinner Alteños appear to maintain a minimum CRP concentration independent of fat-factor, while fatter (or less-thin) Alteños' CRP rises with fat-factor. Female Alteños appear to be trading off investment in immune response for investment in growth and maturation. Alteños' high rate of stunting and absence of obesity suggests chronic, presumably multifactorial, stress. Adipose stores likely buffer against some of these stressors and, in an environment such as this-in which many lack sufficient nutritious foods, potable water, adequate sewage, and health care-may confer a net lifetime benefit.

A new link-legged insulator inspection robot

• The link-legged insulator inspection robot is based on the Chebyshev linkage. • The robot can climb both vertical and horizontal insulator strings. • The robot can carry other executing mechanisms, such as cleaning equipment. • The design is verified in our laboratory by a prototype. Due to the increasing labor power shortage and safety requirements in insulator string inspection, inspection robots have been a primary alternative to replace humans in such an arduous environment. This paper presents a newly designed link-legged insulator inspection robot based on the Chebyshev linkage, which can inspect deteriorated insulators and climb both vertical and horizontal insulator strings. The robot consists of three identical climbing mechanisms, which use two sets of the Chebyshev linkage to achieve the full-time climbing function. An insulator inspecting device is attached to achieve the inspection function. The top of the robot is designed as a flat surface to make it able to carry other executing mechanisms, such as cleaning or vision equipment. This paper also covers a basic robot trajectory planning method, which aims to make the robot climb smoothly and overcome the shortcoming of wide velocity variation in the direction of movement. We have made a prototype of the robot and conducted an experiment in the laboratory, which proves that the robot can climb and inspect both vertical and horizontal insulator strings as desired.

An Ingenious Heritage System for Collecting and Distributing Flood Water in the M’zab Valley of Algeria

Foggaras are traditional Algerian water systems, which historically have made it possible to collect and redistribute water in the Sahara Desert. Although threatened by climate change and unsustainable urbanization, foggaras are still in use today and for hundreds of years have been managed by the same customary laws and groups. They are an example of tangible water heritage and ingenious water works, adapted to the needs of an arduous environment along with local society and culture. Such structures can inspire future ways of engaging with nature.

Prevalence and trigger factors of functional gastrointestinal disorders among male civil pilots in China

Functional gastrointestinal disorders (FGIDs) are common among the aircrew due to their arduous working environment. This study investigated the prevalence of FGIDs in Chinese male pilots and assessed the effects of trigger factors on the FGIDs. A cross-sectional study including 212 male pilots was performed in a Chinese large civil airline company. FGIDs were diagnosed according to the Rome IV diagnostic criteria. The psychological performance, dietary pattern, sleep situation, and physical activity of the respondents were assessed. Logistic regression analysis and structural equation modeling were used to explore the association between these trigger factors and FGIDs. FGIDs were observed in 83 (39.22%) respondents, of which 31 (37.35%) had overlap syndromes. Age, flight level, flight time, high-salt food pattern, anxiety, and sleep performance were found to be associated with FGIDs (all P < 0.05). Stepwise logistic regression analysis revealed that the flight level (OR 0.59, 95% CI 0.31–0.080), high-salt food pattern (OR 2.31, 95% CI 1.28–4.16), and sleep performance (OR 2.39, 95% CI 1.11–5.14) were the influencing factors associated with FGIDs. Structural equation modeling confirmed the correlations between FGIDs and the occupational, dietary, and psychological factors with a reasonable fit. The preventive strategies were necessitated according to occupational and psychological characteristics.

The Open Challenge of in vitro Modeling Complex and Multi-Microbial Communities in Three-Dimensional Niches.

The comprehension of the underlying mechanisms of the interactions within microbial communities represents a major challenge to be faced to control their outcome. Joint efforts of in vitro, in vivo and ecological models are crucial to controlling human health, including chronic infections. In a broader perspective, considering that polymicrobial communities are ubiquitous in nature, the understanding of these mechanisms is the groundwork to control and modulate bacterial response to any environmental condition. The reduction of the complex nature of communities of microorganisms to a single bacterial strain could not suffice to recapitulate the in vivo situation observed in mammals. Furthermore, some bacteria can adapt to various physiological or arduous environments embedding themselves in three-dimensional matrices, secluding from the external environment. Considering the increasing awareness that dynamic complex and dynamic population of microorganisms (microbiota), inhabiting different apparatuses, regulate different health states and protect against pathogen infections in a fragile and dynamic equilibrium, we underline the need to produce models to mimic the three-dimensional niches in which bacteria, and microorganisms in general, self-organize within a microbial consortium, strive and compete. This review mainly focuses, as a case study, to lung pathology-related dysbiosis and life-threatening diseases such as cystic fibrosis and bronchiectasis, where the co-presence of different bacteria and the altered 3D-environment, can be considered as worst-cases for chronic polymicrobial infections. We illustrate the state-of-art strategies used to study biofilms and bacterial niches in chronic infections, and multispecies ecological competition. Although far from the rendering of the 3D-environments and the polymicrobial nature of the infections, they represent the starting point to face their complexity. The increase of knowledge respect to the above aspects could positively affect the actual healthcare scenario. Indeed, infections are becoming a serious threat, due to the increasing bacterial resistance and the slow release of novel antibiotics on the market.

Electronic structure, thermodynamic stability and high-temperature sensing properties of Er-\u03b1-SiAlON ceramics

α-SiAlON ceramics have been in use as engineering ceramics in the most arduous industrial environments such as molten metal handling, cutting tools, gas turbine engines, extrusion molds, thermocouple sheaths, protective cover for high-temperature sensors, etc., owing to their outstanding mechanical, thermal and chemical stability. Taking advantage of the intrinsic properties of α-SiAlONs, we investigate, in this paper, the possibility of using the Er-doped α-SiAlON (Er-α-SiAlON) ceramic as a high-temperature sensing material via its unique near-infrared to visible upconversion property. We first use neutron diffraction and density functional theory calculations to study the electronic structure and thermodynamic stability of Er-α-SiAlON. It is found that the interstitial doping of Er stabilizes the α-SiAlON structure via chemical bonds with O-atoms with N:O ratio of 5:2 in the seven-fold coordination sites of the Er3+ ion. Temperature-dependent upconversion emissions are then studied under 980 and 793 nm excitations over a temperature range of 298–1373 K and the fluorescence intensity ratio (FIR) technique has been employed to investigate the temperature sensing behavior. Temperature-dependent Raman behavior is also investigated. We demonstrate that using Er-α-SiAlON as a sensing material, the limit of temperature measurement via the FIR technique can be pushed well beyond 1200 K.

Evaluation and characterisation of ASS316L at sub-zero temperature

ABSTRACT Austenitic Stainless-Steel grade 316L is one among the significant ASS grades which is most used in various industry sectors. It has excellent corrosion resistance in ordinary atmospheric and in more arduous environments such as saltwater. Whilst performing well when exposed to relatively high temperatures, this grade of ASS also maintains its strength and toughness at sub-zero temperatures, making this an excellent choice for various applications in industrial sectors such as Marine, general construction and water treatment. Therefore, present study focused on evaluating the mechanical properties, ultimate tensile strength (UTS), yield strength (YS) and strain hardening exponent (n) are evaluated based on the experimental data obtained from the uniaxial isothermal tensile tests performed at an interval of −25°C from 0°C to −50°C and at three orientations 0, 45, 90 degrees to the rolling direction and cross-head velocity 3, 5, 7 mm/min were chosen. Total of 27 experiments have been planned based on design-of-experiments. A mathematical model for the prediction of UTS, YS and n was developed using process parameters such as temperature, orientation and cross-head velocities. Results have shown that mechanical properties can be predicted with a reasonable accuracy within the range of process parameters considered in this study.

A novel microbial electrolysis cell (MEC) reactor for biological sulfate-rich wastewater treatment using intermittent supply of electric field

Microbial electrolysis cells (MEC), coupled with sulfate-reducing bacteria (SRB), was used to degrade sulfate-rich wastewater that is deficient in electron donors. However, because of the impact of electric double layers (EDLs), salt crystals formed on the electrode, thereby potentially retarding the continuity of sulfate removal during the whole operation. Here, an improved MEC reactor using intermittent electric field was established. It works better in sulfate removal for a longer period, which was higher than the conventional MEC reactor by 2.18-fold after 10days. Observation on the activity of lactic dehydrogenase (LDH) and ATP revealed that the formation of salt crystals on the electrode led to plasmatorrhexis. Conversely, improved reactor contributed to extracellular substances production and prevented the salt crystal formation, which was conducive to biofilm formation as further verified by detection through SEM. Electrochemical impedance spectroscopy tests showed that the cathodic microorganisms accelerated electron transfer whereas the salt crystals increased the charge transfer resistance. High-throughput sequencing analysis illustrated that improved reactor could maintain the competitiveness of SRB in the microbial community for a longer period. Moreover, the improved reactor resulted in high species diversity, thereby showing the significant resistance of the microorganisms to arduous environments.

Determination of sand dune characteristics through geomorphometry and wind data analysis in central Iran (Kashan Erg)

The combination of wind measurements and remotely sensed geomorphometry indices provides a valuable resource in the study of desert landforms, because arduous desert environments are difficult to access. In this research, we couple wind data and geomorphometry to separate and classify different sand dunes in Kashan Erg in central Iran. Additionally, the effect of sand-fixing projects on sand dune morphology was assessed using geomorphometry indices (roughness, curvature, surface area, dune spacing and dune height). Results showed that a Digital Elevation Model of the National Cartographic Center of Iran (NCC DEM) with 10-m resolution and accuracy of 54% could discriminate geomorphometry parameters better than the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data with 30-m resolution and Shuttle Radar Topography Mission (SRTM) data with 90-m resolution and 45.2 and 1.6% accuracy, respectively. Low classification of SRTM DEM was associated with too many non-value points found in the DEM. Accuracy assessment of comparison ground control points revealed that ASTER DEM (RMSE = 4.25) has higher accuracy than SRTM and NCC DEMs in this region. Study of curvature showed that transverse and linear sand dunes were formed in concave topography rather than convex. Reduced slopes in fixed sand dunes were established due to wind erosion control projects. Measurements of dune height and spacing show that there is significant correlation in compound dunes (R 2 = 0.546), linear dunes (R 2 = 0.228) and fixed dunes (R 2 = 0.129). In general, the height of dunes in Kashan Erg increases from the margin of the field to the center of the field with a maximum height of 120 m in star dunes. Analysis of wind data showed that sand drift potential is in low-medium class in Kashan Erg. Linear sand dunes in Kashan Erg show that they are following a global trend in forming of these. Finally, established of geomorphometry method in dune classification will help researchers to identify priority of land management and performance assessment of sand dunes fixing projects in arid arduous environment.

ENT entry requirements for UK armed forces.

Minimum health requirements exist for entry into the UK armed forces. Both pre-existing and iatrogenic ENT conditions may impact on an individual's medical fitness and their ability to enter the forces. The relevant literature was examined and military otolaryngology advisors were interviewed in order to define the ENT-specific conditions that restrict an individual joining the armed forces. The ENT diseases and disabilities that inhibit an individual's ability to join the forces are described. Treatments that may facilitate or restrict recruitment are also discussed. Members of the armed forces operate in arduous environments and are required to pass a screening medical assessment before joining. Personnel may be isolated away from specialist care and therefore cannot be dependent on specialist devices or medicines. This paper aims to arm ENT specialists with occupational knowledge to enable them to correctly counsel patients and offer appropriate treatment.

The mineral prospecting expeditions to the South Atlantic islands and Antarctic Peninsula region made by the Scottish geologist David Ferguson, 1912–1914

Synopsis David Ferguson’s mineral prospecting expeditions to South Georgia (1912), the Falkland Islands and the South Shetland Islands (1913–1914), on behalf of the Christian Salvesen whaling company of Leith and now largely forgotten, were early examples of commercially motivated terrestrial exploration in the South Atlantic region. Prior geological knowledge was very limited and Ferguson complemented his unsuccessful prospecting work with attempts to understand the regional geology of the areas that he visited. These interpretations were based on relatively cursory fieldwork undertaken in an arduous environment, and did not prove robust; but the well-documented specimen collections that Ferguson accumulated provided the basis for excellent and much-cited petrographical accounts by G. W. Tyrrell of Glasgow University. Ferguson had studied geology at the university and the influence of his mentor there, Professor J. W. Gregory, is apparent. In turn, Gregory utilized Ferguson’s observations in support of a subsided ‘South Atlantic continent’, opposing the ‘displacement hypothesis’ for that region formalized by Alfred Wegener from 1912 onwards. Ferguson’s field notebooks and most of his rock specimens are now held by Glasgow University (Archive Services and Hunterian Museum, respectively) but he distributed representative specimen collections widely, and these are extant in several other British museums. Specimens were also supplied to, and discussed with, William Speirs Bruce who, following the 1902–1904 Scottish National Antarctic Expedition, took a keen interest in Ferguson’s discoveries.

A Four-Wheel-Rhombus-Arranged Mobility System for a New Lunar Robotic Rover

Different from traditional ground vehicles, planetary robotic rovers with limited weight and power need to travel in unfamiliar and extremely arduous environments. In this paper, a newly developed four-wheel-rhombus-arranged (FWRA) mobility system is presented as a lunar robotic rover with high mobility and a low-weight structure. The mobility system integrates independent active suspensions with a passive rotary link structure. The active suspension with swing arms improves the rover's capacity to escape from a trapped environment whereas the passive rotary link structure guarantees continuous contact between the four wheels and the terrain. The four-wheel-three-axis rhombus configuration of the mobility system gives a high degree of lightweight structure because it has a simple mechanism with the minimum number of wheels among wheeled rovers with three-axis off-road mobility. The performance evaluation of the lightweight nature of the structure, manoeuvrability and the mobility required in a planetary exploring environment are illustrated by theoretical analysis and partly shown by experiments on the developed rover prototype.

Management of heat emergencies in the military setting

The Australian Defence Force (ADF) has long battled in hot and arduous environments. From the trenches of Tobruk during World War II and the thick jungle of Vietnam through to current theatres of war such as the rugged mountains of Afghanistan. Australian soldiers are exposed to the constant threat of heat illness, and while avoidable in training settings, it cannot be prevented in some combat situations. Prevention however, is a key factor in the exclusion of heat illness cases, a matter that the ADF has worked hard to highlight through mandatory annual training. It is for this reason that military heat casualty rates remain low in the ADF. This article provides some useful assessment tools which help to differentiate between the different levels of heat illness; and furthermore, underlines the critical stages of heat illness and includes literature on the aetiology, pathophysiology, clinical manifestations and prehospital care management of heat illness.

Microstructural characterisation of oxide formation from MCrAlY coatings on nickel-based superalloys

Nickel-based superalloys are commonly used in industrial gas turbine engines for power generation due to their ability to withstand the arduous environments. Coating systems are employed to increase the service life of components by increasing the oxidation\\corrosion resistance and high temperature capabilities. MCrAlY coatings are a common coating system used, not only to protect the substrate from oxidation and corrosion but also to act as a bond coat for thermally insulating coatings. The ‘M’ in the MCrAlY coatings is generally Ni, Co or a mixture of the two, with Co being added to improve the hot corrosion resistance (in conjunction with Cr) and to make the coatings more ductile. These coatings work by forming oxides that act as protective layers against further oxidation (known as the thermally grown oxide, TGO). Alumina is most commonly formed oxide from the MCrAlY bond coat, which acts as a reservoir of elements for the oxide formation.It is necessary to understand the formation and nature of the TGO as a function of composition variation in the coating. This mechanistic understanding can be used to inform modelling methodologies for both service life prediction and the development of new coatings. This research is therefore concerned with the effect of compositional changes in the MCrAlY coating and their effect on the TGO formation. Various ageing temperatures and times have been studied, representative of service conditions. The alumina layer has been studied, however, the formation of other oxides, including isolated spinels, has been characterised in detail. Microstructural observations were carried out using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis and electron backscattered diffraction. Higher resolution characterisation was carried out using a dual beam focused ion beam scanning electron microscope for site specific TEM preparation and STEM/TEM for microstructural evaluation. The results are then discussed in the light of both the bond coat composition and ageing conditions.

Nearness Diagram (ND) Navigation: Collision Avoidance in Troublesome Scenarios

This paper addresses the reactive collision avoidance for vehicles that move in very dense, cluttered, and complex scenarios. First, we describe the design of a reactive navigation method that uses a "divide and conquer" strategy based on situations to simplify the difficulty of the navigation. Many techniques could be used to implement this design (since it is described at symbolic level), leading to new reactive methods that must be able to navigate in arduous environments (as the difficulty of the navigation is simplified). We also propose a geometry-based implementation of our design called the nearness diagram navigation. The advantage of this reactive method is to successfully move robots in troublesome scenarios, where other methods present a high degree of difficulty in navigating. We show experimental results on a real vehicle to validate this research, and a discussion about the advantages and limitations of this new approach.

The effect of structural features on mechanical properties of loose optical fiber poly(butylene terephthalate) tubes

AbstractResults of a study on the modifying mechanical properties of loose optical‐fiber poly(butylene terephthalate) (PBT) tubes, produced during the standard industrial extrusion process, show that heat treatment make the structure of their material to change. The study comprised measurements of mechanical strengths properties of the tubes (tensile strength, compression strength, kinking) and determination of tube material structure [by differential thermal analysis (DTA), wide angle X‐ray scattering analysis (WAXD), and scanning electron microscopy (SEM)]. Results of the study allowed observation that the annealing at 70°C for 34 h of the tubes caused the crystalline α phase to increase in the tube material from ∼28.5% to ∼31.5% and the structure of the existing crystallites to become more perfect. This made the values of certain mechanical properties of the tubes to increase even by as much as 30%. The tubes following such thermal treatment could be used in cables exposed to heavy‐duty operation in arduous environments, where a larger margin from the standpoint of mechanical properties is required. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2130–2134, 2002

Fitness Levels of Firefighter Recruits Before and After a Supervised Exercise Training Program

Federal law prohibits pre-employment physical examination of firefighter recruits, but these workers must perform intense exercise in arduous environments. Components of physical fitness of rookie firefighters (n = 115; 104 men, mean +/- SD: age = 28.3 +/- 4.3 years; height = 1.76 +/- 0.07 m; weight = 83.2 +/- 13.9 kg; percent body fat = 17 +/- 8%) were measured upon being hired and following a 16-week exercise training program (1 h.d(-1), 3 d.wk(-1)) designed to improve physical fitness. Maximum aerobic capacity (VO2max) was estimated from submaximal cycle ergometry, body composition from skinfold tests, flexibility from a sit and reach test, strength by hand grip dynamometry, and muscle endurance by a push-up test. The results are as follows (*, p <or= 0.007 vs. pretraining): VO2max increased by 28% (35 +/- 7 to 45 +/- 6* ml.kg(-1).min(-1), 88 +/- 20 to 113 +/- 17%* of predicted increase); muscle endurance increased (41 +/- 13 to 51 +/- 14* push-ups); flexibility increased (0.34 +/- 0.07 to 0.35 +/- 0.07* m); muscle strength tended to increase (102.9 +/- 18.7 to 105.4 +/- 18.7 kg, p = 0.06); body weight tended to decrease (83.2 +/- 13.9 to 82.7 +/- 13.2 kg, p = 0.06); lean tissue weight increased (68.8 +/- 9.9 to 69.9 +/- 9.5* kg); and fat weight decreased (14.6 +/- 8.0 to 13.0 +/- 7.1* kg). We concluded that aerobic capacity was 20% lower before training than that deemed sufficient for safe performance of fire suppression duties; that training improved aerobic capacity by 28%, decreased fat and increased lean tissue weight, and increased/tended to increase other components of physical fitness. Prior to initiation of this training program, aerobic capacity of these firefighters was below that deemed appropriate for performing fire suppression duties. Training resulted in a large increase in aerobic capacity, so that the trainees ended the program with an aerobic capacity considered appropriate for fighting fires. It is hoped that the results of this study will encourage those who oversee workers who are responsible for the public's safety to mandate assessment of physical fitness of new hires, with mandatory participation in exercise training for those new hires who are found to possess less than appropriate aerobic capacity.

A Field Evaluation Of Pulse Oximetry In Two Arduous Environments

Two portable battery powered pulse oximeters were tested on Joint Services expeditions to the Sahara Desert and the Andes mountains. Their ability to measure changes in pulse, oxygen saturation of...

A review of gas-gas heat recovery systems

Gas-gas heat recovery systems are probably the most prolific in all application areas, and are certainly of considerable interest for rapid ‘retro-fitting’ on industrial plant as an energy saving measure. They are of growing importance in the home, and their use in large HVAC systems is now mandatory in Sweden. A major development effort in equipment design to meet the requirements of more arduous environments and economic constraints is evident in many countries. This paper reviews this field, giving descriptions of equipment available and, for the more important systems, factors to be taken into account in their selection.