| 1. |
- Del Ferraro, Simona, et al.
(författare)
-
A potential wearable solution for preventing heat strain in workplaces : The cooling effect and the total evaporative resistance of a ventilation jacket
- 2022
-
Ingår i: Environmental Research. - : Elsevier BV. - 1096-0953 .- 0013-9351. ; 212
-
Tidskriftsartikel (refereegranskat)abstract
- The increase in average seasonal temperatures has an impact in the occupational field, especially for those sectors whose work activities are performed outdoors (agricultural, road and construction sectors). Among the adaptation measures and solutions developed to counteract occupational heat strain, personal cooling garments represent a wearable technology designed to remove heat from the human body, enhancing human performance. This study aims to investigate the effectiveness and the cooling power of a specific cooling garment, i.e. a ventilation jacket, by quantifying the evaporative heat losses and the total evaporative resistance both when worn alone and in combination with a work ensemble, at three adjustments of air ventilation speed. Standardised "wet" tests in a climatic chamber were performed on a sweating manikin in isothermal conditions considering three clothing ensembles (single jacket, work ensemble and a combination of both) and three adjustments of fan velocity. Results showed a significant increase (p < 0.001) in evaporative heat loss values when the fan velocity increased, particularly within the trunk zones for all the considered clothing ensembles, showing that fans enhanced the dissipation by evaporation. The cooling power, quantified in terms of percent changes of evaporative heat loss, showed values exceeding 100% when fans were on, in respect to the condition of fans-off, for the trunk zones except for the Chest. A significant (p < 0.01) decrease (up to 42.3%) in the total evaporative resistance values of the jacket, coupled with the work ensemble, was found compared to the fans-off condition. Results confirmed and quantified the cooling effect of the ventilation jacket which enhanced the evaporative heat losses of the trunk zones, helping the body to dissipate heat and showing the potential for a heat adaptation measure to be developed.
|
|
| 2. |
- Del Ferraro, Simona, et al.
(författare)
-
Cooling garments against environmental heat conditions in occupational fields : measurements of the effect of a ventilation jacket on the total thermal insulation
- 2021
-
Ingår i: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141. ; 86
-
Tidskriftsartikel (refereegranskat)abstract
- Personal cooling garments (PCGs) can represent an adaptation solution to counteract heat strain and to improve worker's health and productivity (especially for some outdoor work activities as in agriculture and in the construction industry). The cooling effect of a ventilation jacket was preliminarily investigated carrying out “dry” tests in a climatic chamber on a thermal manikin. A standardized condition with air temperature, ta = 22.4 °C, three different adjustments of the fan velocity (vf= 0, vf = 2 and vf = 4), and three different ensembles (the single jacket, a work ensemble and a combination of both) were considered. Results showed significant increases in dry heat losses (through convection) for the trunk thermal zones, higher when the fans were on, for all the ensembles considered. Percent changes greatly exceeded 100 % for the thermal zones close to the fans. The air ventilation determined significant decreases of the total thermal insulation (IT) values (up to 35 %) compared to the fans-off condition, confirming and quantifying the cooling effect of the ventilation jacket.
|
|
| 3. |
- Del Ferraro, Simona, et al.
(författare)
-
Mitigating heat effects in the workplace with a ventilation jacket : simulations of the whole-body and local human thermophysiological response with a sweating thermal manikin in a warm-dry environment
- 2024
-
Ingår i: Journal of Thermal Biology. - 0306-4565. ; 119
-
Tidskriftsartikel (refereegranskat)abstract
- Climate change is increasingly affecting human well-being and will inevitably impact on occupational sectors in terms of costs, productivity, workers' health and injuries. Among the cooling garment developed to reduce heat strain, the ventilation jacket could be considered for possible use in workplaces, as it is wearable without limiting the user's mobility and autonomy. In this study, simulations with a sweating manikin are carried out to investigate the effects of a short-sleeved ventilation jacket on human thermophysiological responses in a warm-dry scenario. Simulations were performed in a climatic chamber (air temperature = 30.1 °C; air velocity = 0.29 m/s; relative humidity = 30.0 %), considering two constant levels of metabolic rate M (M 1 = 2.4 MET; M 2 = 3.2 MET), a sequence of these two (Work), and three levels of fan velocities (l f = 0; l f=2; l f=4). The results revealed a more evident impact on the mean skin temperature (T sk) compared to the rectal temperature (T re), with significant decreases (compared to fan-off) at all M levels, for T sk from the beginning and for T re from the 61 st minute. Skin temperatures of the torso zones decreased significantly (compared to fan-off) at all M levels, and a greater drop was registered for the Back. The fans at the highest level (l f=4) were significantly effective in improving whole-body and local thermal sensations when compared to fan-off, at all M levels. At the intermediate level (l f=2), the statistical significance varied with thermal zone, M and time interval considered. The results of the simulations also showed that the Lower Torso needs to be monitored at M 2 level, as the drop in skin temperature could lead to local overcooling and thermal discomfort. Simulations showed the potential effectiveness of the ventilation jacket, but human trials are needed to verify its cooling power in real working conditions.
|
|
| 4. |
- Ripepi, Vincenzo, et al.
(författare)
-
The VMC survey - XLVIII. Classical cepheids unveil the 3D geometry of the LMC
- 2022
-
Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 512:1, s. 563-582
-
Tidskriftsartikel (refereegranskat)abstract
- We employed the VISTA near-infrared YJKssurvey of the Magellanic System (VMC) to analyse the Y, J, and Ks light curves of δCepheid stars (DCEPs) in the Large Magellanic Cloud (LMC). Our sample consists of 4408 objects accounting for 97 per cent of the combined list of OGLE IV and Gaia DR2 DCEPs. We determined a variety of period-luminosity (PL) and period-Wesenheit PW relationships for Fundamental (F) and First Overtone (1O) pulsators. We discovered for the first time a break in these relationships for 1O DCEPs at P= 0.58 d. We derived relative individual distances for DCEPs in the LMC with a precision of ∼1 kpc, calculating the position angle of the line of nodes and inclination of the galaxy: θ = 145.6 ± 1.0 deg and i = 25.7 ± 0.4 deg. The bar and the disc are seen under different viewing angles. We calculated the ages of the pulsators, finding two main episodes of DCEP formation lasting ∼40 Myr which happened 93 and 159 Myr ago. Likely as a result of its past interactions with the SMC, the LMC shows a non-planar distribution, with considerable structuring: the bar is divided into two distinct portions, the eastern and the western displaced by more than 1 kpc from each other. Similar behaviour is shown by the spiral arms. The LMC disc appears 'flared' and thick, with a disc scale height of h ∼0.97 kpc. This feature can be explained by strong tidal interactions with the Milky Way and/or the Small Magellanic Cloud or past merging events with now disrupted LMC satellites.
|
|
| 5. |
- Wang, Faming, et al.
(författare)
-
Localised boundary air layer and clothing evaporative resistances for individual body segments.
- 2012
-
Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 55:7, s. 799-812
-
Tidskriftsartikel (refereegranskat)abstract
- Evaporative resistance is an important parameter to characterise clothing thermal comfort. However, previous work has focused mainly on either total static or dynamic evaporative resistance. There is a lack of investigation of localised clothing evaporative resistance. The objective of this study was to study localised evaporative resistance using sweating thermal manikins. The individual and interaction effects of air and body movements on localised resultant evaporative resistance were examined in a strict protocol. The boundary air layer's localised evaporative resistance was investigated on nude sweating manikins at three different air velocity levels (0.18, 0.48 and 0.78 m/s) and three different walking speeds (0, 0.96 and 1.17 m/s). Similarly, localised clothing evaporative resistance was measured on sweating manikins at three different air velocities (0.13, 0.48 and 0.70 m/s) and three walking speeds (0, 0.96 and 1.17 m/s). Results showed that the wind speed has distinct effects on local body segments. In contrast, walking speed brought much more effect on the limbs, such as thigh and forearm, than on body torso, such as back and waist. In addition, the combined effect of body and air movement on localised evaporative resistance demonstrated that the walking effect has more influence on the extremities than on the torso. Therefore, localised evaporative resistance values should be provided when reporting test results in order to clearly describe clothing local moisture transfer characteristics. Practitioner Summary: Localised boundary air layer and clothing evaporative resistances are essential data for clothing design and assessment of thermal comfort. A comprehensive understanding of the effects of air and body movement on localised evaporative resistance is also necessary by both textile and apparel researchers and industry.
|
|
| 6. |
|
|
