Comparison of thermal responses with and without cold protective clothing in a warm environment after severe cold exposures

1. 1. Ten male students remained in a severely cold room (-25°C) for 20 min. thereafter, they transferred in a warm room (25°C) for 20 min.

2. 2. This pattern was repeated three times, total cold exposure time amounting to 60 min.

3. 3. In the warm room, the subjects removed their cold-protective jackets, or wore them continously.

4. 4. Rectal temperature, skin temperatures, manual performance and thermal comfort were measured during the experiment.

5. 5. Removing cold-protective jackets after severe cold exposure increased peripheral skin temperatures and reduced the discomfort in the warm room.

6. 6. However, these results were accompanied by a greater decrease in rectal temperature and manual performance.

7. 7. It is recommended that workers continue to wear cold-protective clothing in the warm areas outside of the cold storage to prevent decreases in deep body temperature and work efficiency caused by repated cold exposures.

SCENARIO revisited: comparisons of operational and rational models in predicting human responses to the environment

1. This paper focuses on thermoregulatory modeling of individual variability in environmental extremes.

2. A great many worthwhile models do a reliable job describing the heat balance equation using a first principles approach by fitting operational equations or by using multi-node thermoregulatory servo-control models.

3. A soldier-based physiological/thermoregulatory model (SCENARIO (J. Therm. Biol. 22 (1997) 331) was enhanced using a probabilistic application of the Bayesian statistical paradigms in conjunction with Monte Carlo methods (SCENARIO-MC).

4. Coefficients improving the model include: algorithms for circadian and menstrual cycle offsets on the hypothalamic controller and an output depiction of correlation matrices between specific environmental and physiologic variables.

5. The model was found to be robust (based on root mean square deviations ) particularly in physiological strain index prediction and able to predict individual esophageal and heart rate responses in women exposed to upward and downward thermal transients and wide perturbations of work/rest exercise in the heat while wearing protective clothing.

Characteristics of the temperature regulation system in the human body

1. 1. To study a complex biological system such as human temperature regulation, it is necessary to consider both physiological experiments and theoretical analysis.

2. 2. This paper presents the characteristics of this temperature regulation system obtained from a mathematical model, together with experimental data and the influence of exercise and clothing.

3. 3. The experimental results showed a good agreement with the theoretical results.

Effect of hygroscopic fabrics on wear comfort in the fluctuating microclimate of clothing

1. 1. A new type of simulator for clothing microclimate was designed and constructed.

2. 2. The simulator was designed to simulate the humidity fluctuation of clothing microclimate as observed under light working conditions and to measure the surface temperature of sample fabrics against the skin by means of a radiation thermometer.

3. 3. Knitted fabrics of cotton and polyester, and polyethylene films were used as specimens with different hygroscopicities.

4. 4. The quick rise and fall in the surface temperature of cotton fabric was observed under rapid fluctuations of the microclimate humidity.

5. 5. Under the same humidity fluctuations, the temperature of polyester fabric rose and fell more moderately than that of cotton fabrics, and the temperature of the polyethylene film did not change. When the rate of change in stimulus temperature is higher, the threshold temperature of warm sensation of the skin comes closer to a given adaption temperature.

6. 6. Therefore, the rapid and large changes in the fabric temperature against the skin, which were observed especially for hygroscopic cotton fabric, must affect the thermal comfort of clothing.

Indoor environmental study and post occupancy evaluation in an office environment

1. 1. The objective of this paper is to investigate the indoor environment from the viewpoint of interaction between physical environment and the human responses. The field survey has been conducted over 1 year.

2. 2. A continuous measurement has been carried out for 1 week and distribution of variables have been measured for 1 day.

3. 3. The attitude of workers was investigated by a questionnaire.

4. 4. As the result, average luminance represented more than 1000 lx in the new building, in contrast with less tha 300 lx in the existing building.

5. 5. There was a significant difference of the occupants' response to the light environment between the two buildings.

6. 6. Measured thermal conditions are on the edge of the ASHRAE comfort envelope in summer, and in the neighborhood of the lower dry limit of the envelope in spring.

7. 7. The occupants' evaluations were remarkably changed before and after the moving. The office environment is better than that of the factory.

Transient response of the human-clothing system

1. 1. A transient clothing model which considers the effects of adsorption and thermal capacitance on the dynamic thermal response of clothing was developed.

2. 2. Moisture adsorption and desorption by the fabric are the major factors that affect the transient response of clothing.

3. 3. This moisture can come from evaporated sweat or from the environment.

4. 4. The clothing model was combined with a modified version of the two-node thermal model of the human body.

5. 5. The combined model shows that, during transients, the mix of latent and sensible heat flow from the skin may differ considerably from the corresponding heat flows from the clothing surface to the environment.

6. 6. The alteration of the heat flows can have a significant impact on the thermal response of the body by changing the sweat rate required to achieve the heat loss necessary to maintain thermal balance.

Estimation of thermal sensation using PMV and SET under high air movement conditions

1. 1. Our previous experimental results showed the thermal sensation vote was much less than the values of PMV and SET^* at air velocities above 0.5 m/s.

2. 2. The method to modify SET^* is presented from the results of subjective experiments taking account of decrease in clo value of summer clothing and decrease in skin wettedness due to increased air velocity.

3. 3. Thermal resistance under increased air movement on a standard summer clothing ensemble was measured. Basic thermal insulation of the summer ensemble was reduced by 25% at air velocity of 1.0 m/s.

4. 4. Thirty-two subjects were exposed at operative temperatures of 27 and 30°C under 1 m/s air movement in order to determine the amount of skin diffusion. Measured evaporation heat loss from skin surface was much smaller at air velocity of 1 m/s than that predicted by SET^*.

5. 5. Estimated thermal sensation vote using modified SET^* agreed well with our previous experimental results under different air velocities for the same clothing.

TLV in cold environments

1. 1. The risks encountered during cold exposure are general body cooling or local cooling of parts of th body.

2. 2. Measures of cold stress must account for the effects of climate, clothing and metabolic heat production on heat balance.

3. 3. The combinaed effect of air temperature, mean radiant temperature, humidity and air velocity determines the cooling power of the environment.

4. 4. The cooling power can be easily converted into a required insulation value (IREQ) for whole body heat balance.

5. 5. Extensive cooling of hands and feet may be a limiting factor, even when sufficient total insulation is provided. In addition the cooling effect of wind on unprotected skin must be considered.

6. 6. Recommendation regarding acceptable exposures can be expressed as lowest ambient temperatures and time limits as function of available protection and activity level, with due attention to both general and local effects.

Adaptation of industrial/commercial air conditioners for use in a thermally stressful environment

1. 1. The concept of intermittent, microclimate cooling during rest periods has been investigated due to the logistical and ergonomic problems associated with backpack cooling systems

2. 2. In an attempt to improve intermittent cooling applications, the use of industrial/commercial air conditioners (ICAC) as a source of cool air was conceived

3. 3. In the current study, a prototype of a pressurized air distribution unit (PADU) which can be incorporated into existing ICAC was designed and fabricated

4. 4. In a successful test, an ICAC circulated air and cooled it down to the set temperature, while the PADU pumped 5101/min (the specified air volume for one person) of 15°C into each air cooling vest, 4601/min to the body and 501/min to the face, through filters and 10 ft/1 in. diameter supply line

5. 5. The PADU is necessary to increase the air pressure in the system, creating the required air volume

6. 6. This promising concept adapts existing ICAC to provide adequate amounts of clean, cool air to individuals working in thermally stressful environments

7. 7. This development effectively increases the conditioned air sources available for use in decreasing heat storage and increasing personal comfort in military or civilian scenarios where work is conducted in protective garments.

Relationships between forced vital capacity and subjective responses to added resistive load to inspiration

1. 1. This study was conducted to investigate the effects of forced vital capacity on breathing pattern and subjective responses to inspiratory resistance.

2. 2. The subjects were divided into two groups according to their %FVC [large (L) and small (S) group; five subjects in each].

3. 3. Added inspiratory resistances were 0.6 (control), 1.5 (R1), 2.5 (R2), 3.1 (R3) cmH₂O · 1⁻¹ · s.

4. 4. Breathing pattern was analyzed by personal computer during rest and exercise with bicycle ergometer.

5. 5. The degree of sensation of breathing difficulty was expressed in SNS reported in our previous study.

6. 6. SNS in S group increased with resistance while no tendency was observed in L group. SNS in S group was significantly greater than that in L group at R3 condition.

7. 7. The breathing pattern of S group was characterized in smaller tidal volume and faster respiratory frequency compared to those of L group with no resistive load.

8. 8. However, outstanding changes in breathing pattern were observed in S group with longer inspiratory time and lower mean inspiratory flow rate when resistive loads were added, which led to increased tidal volume and decreased respiratory frequency.

Lactate modeling and its application to endurance training

1. 1. In this short review, previous studies regarding the modeling of lactate (La) response to exercise and its application to endurance training have been summarized.

2. 2. Additionally the result of a recent study by the present authors are shown.

3. 3. Several models for La response to step and ramp exercise are already proposed and deductions derived from them are used for practical purposes such as the prediction of race performance in middle-and long-distance runners as well as for construction of their training regimens.

4. 4. Only a limited number of models however have tried to quantify whole body La kinetics to exercise in humans concomitantly with describing physiological mechanisms underlying the observed phenomenon.

5. 5. In a recent study described further in this paper a 2 compartment model was used for the purpose of clarifying the current “La production vs degradation” controversy during La adaptation to training.

6. 6. It was determined from this investigation that the La metabolic clearance rate during recovery is enhanced by the endurance training.

7. 7. This is in accordance with another recent observation of an increased La metabolic clearance rate at high absolute work rates and all relative work rates during exercise.

Bed climate of Korean using ondol heating system

1. 1. To examine the influence of different bed conditions (ondol sleep, bed sleep on ondol with same bedding) of the Korean ondol traditional heating system on human response during sleep, bed climates and physiological responses such as skin and rectal temperatures, weight loss, body movement and subjective sensation were measured with 4 grown-up females as subjects while they were sleeping for 7 h.

2. 2. Bed climate: Temperatures under the mattress and inside the quilt were higher on ondol while temperatures on the mattress and humidity inside the quilt were higher on the bed.

3. 3. Rectal temperature was significantly higher on ondol; skin temperature showed no major differences in relation to bed conditions. The frequency of body movements had the highest correlation with bed climate of the parameters measured.

4. 4. Mattress weight decreased on ondol and increased on the bed.

5. 5. The frequency of body movements was significantly higher in ondol sleep.

6. 6. The subjects sensation showed difference on cushion sensation between the two types of bed condition.

7. 7. To obtain the same level of comfort on both ondol and bed sleeping conditions less thermal insulating value is needed for ondol sleep.

Some problems and counter-measures in modern labour. From single causal factors assessment to the analysis of multiple forms of hardship at work

1. 1. Methods are needed through which work situations can be analyzed in terms of the complex set of circumstances which they in fact involve.

2. 2. A number of office workplaces were examined with respect to both physical aspects of the work premises and the content of work. The study of task-related complaints was limited to those which are related to aspects of office work conducted using computer terminals (VDT work).

3. 3. For the purpose of illuminating the combined importance of office design and working conditions of the VDT work, the study considered the occurrence of complaints related to both sources.

4. 4. A questionnaire study (containing about 250 questions) covering all employees in eight workplaces and 269 people in total, of which 195 were VDT operators.

5. 5. The concepts, source of complain, type of complaint and were used to provide an analysis of the composite picture of complaints.

6. 6. A combination of premises-related and VDT-related complaints applies to a large number of office workers and only a few people stated were wholly free from difficulties.

7. 7. The findings indicate that by also taking account of the design of office premiss as a source of hardship, we have obtained further report for the view that the pattern of complaints is rather complicated in the case of most people who devote themselves to VDT work.

8. 8. Climatic problems arise extremely frequently, as too do problems in obtaining an appropriate balance between privacy and social contact at work.

Muscle potentials and temperature acclimation and acclimatization in flight muscles of workers and drones of Apis mellifera

1. 1.Muscle potentials in fibrillar flight muscles of worker and drone honeybees were recorded extracellularly at thoracic temperatures from 30 to 10°C.

2. 2.Extinction temperatures for muscle potentials were higher in drones for all treatments.

3. 3.Cold acclimation (15°C) lowered extinction temperatures significantly in workers and drones. Acclimitization changed extinction temperatures significantly only in drones.

4. 4.Cold acclimitization had a bigger effect on the rate of muscle potential amplitude decline with decreasing temperature than acclimation.

5. 5.Acclimation and acclimitization had no effect on the increase of muscle potential duration with falling temperature.

6. 6.Muscle potential frequency during shivering was not much different between cold and warm treated bees.

Research on office environment evaluation and worker fatigue

1. 1. The purpose of this research was to study the relationship between indoor environment and fatigue by analyzing office workers' fatigue and evaluation of indoor environment according to occupation.

2. 2. This study concerned office workers' fatigue (before and after work), questionnaires on indoor environment, and measurement of the physical environment. The subject (562 people) were businessmen, interior designers, and salesmen.

3. 3. The result of this study showed that there was a high correlation between the office workers' feeling of fatigue and the office environment.

4. 4. This research demonstrated that the workers of each type of occupation responde differently to similar office environments.

Variability in rate of human perspiration in european populations

1. 1. In the consideration of ergonomic tasks the attempt is often made to combine the results of physiological research on human perspiration with technical factors such as the transfer of moisture through specific materials.

2. 2. The result of such attempts is often unsatisfactory due to the fact that the percentiles and frequency distribution of perspiration rates are often unknown or not taken into consideration.

3. 3. Further, the interaction between the human user and a particular environmental situation remains unaccounted for.

4. 4. This interaction can produce totally different reactions in both the user and the materials depending upon the specifics of the situation.

5. 5. In response to this deficit we tested 738 persons from various areas in Europe under laboratory conditions to determine perspiration rates and their statistical distribution.

6. 6. Despite the climatic differences existing within Europe, a uniform picture characterized by an extremely skewed distribution resulted.

7. 7. However, it was also shown that these values, including their statistical distribution and percentile ranks, can be strongly influenced by specific external conditions.

8. 8. In the design of human working and living environments it is necessary to examine the situation with research subjects whose perspiration rates are known in order to gain insight into the interactions existing between the human user and the material or technical aspects of the particular environment in question.

Work at cold storage

1. 1. Work activities in cold storage rooms were assessed by a mailed questionnaire survey of cold storage facilities in Japan.

2. 2. There are nearly 4000 cold storage facilities and about 80% are being kept at temperatures below −20°C.

3. 3. The chief items of stock in storage were marine products, livestock products, frozen food and agricultural products.

4. 4. Methods used for loading and unloading in cold storage rooms are forklift, manual handling, and automatic machines.

5. 5. Use of forklifts appeared to be widespread.

6. 6. Working time differed according to the ambient temperature of the cold storage rooms.

7. 7. Common ailments of cold storage workers are lumbago, bronchitis, neuralgia etc.

Study of function of fingers by physiological tremor

1. 1. Physiological tremor is invisible mechanical vibration of body parts.

2. 2. It has two peak frequencies in the p ower spectrum. The origin of the peaks has not been well elucidated. Therefore, the mechanism and its application to labor science is studied in the paper.

3. 3. The effect of immersion of fingers in water and of loading weights on fingers are performed to elucidate the mechanism involved.

4. 4. It is found that the power spectrum output has two bands from the lower frequency band (1.5–18 Hz) from the CNS and the higher frequency band (18–50 Hz).

5. 5. These results are applied to the evaluation of fatigue of fingers in tapping and typing work.

6. 6. The total power, which is the sum of power spectrum in frequency range between 1.5 and 50 Hz, is employed as evaluational index. The change of total power explains finger fatigue during tapping and typing loads.

7. 7. Physiological tremor is an effective way of evaluating the function of fingers in human work.

Factors affecting the resistance to heat transfer provided by clothing

1. 1. This paper discusses the factors that affect the insulation and evaporative resistance provided by clothing.

2. 2. These include: fabric thickness and density, the amount of body surface area covered by garments, the evenness of the distribution of fabrics over the body surface, the increase in surface area for heat loss due to clothing, the looseness or tightness of fit, a person's body position (seated vs standing), body motion and wind.