The influence of occupant control behaviour on thermal comfort under different heating charging modes in residential buildings in cold regions.

In China's central heating, there are two modes for calculating heating costs, which are divided into Charging by flow mode which charges according to the amount of use and Charging by area mode which charges according to the floor area. The Charging by flow mode has been increasingly adopted by numerous urban central heating buildings. Thus it is worth investigating whether occupants experience varying levels of thermal comfort under these two modes. To address this, a field test and subjective questionnaire survey were conducted on residential buildings in cold regions of China during the heating season. The study assessed 134 residential occupants utilizing radiator heating, comprising 66 in Charging by area and 68 in Charging by flow modes. A collection of 1206 valid data points was obtained, with 609 in Charging by area mode and 597 in Charging by flow mode. The findings reveal noteworthy disparities in the duration, area, and strength of heating equipment usage between the two modes. While there are no marked variances in the interior and exterior environmental conditions under both modes, residents in the Charging by flow mode experience enhanced thermal comfort, acceptability and expectation, as well as better air quality satisfaction. Perceived control can greatly enhance individuals' thermal sensation in temperatures below 18 °C and above 24 °C. The impact of perceived control on thermal expectation is linear with temperature adjustments. The heightened degree of sensing control in Charging by flow mode lowers residents' expectations of high temperatures, broadens the range of acceptable low temperatures and accomplishes energy conservation and carbon reduction while ensuring optimal comfort.

Historic Variations in Winter Indoor Domestic Temperatures and Potential Implications for Body Weight Gain.

It has been argued that the amount of time spent by humans in thermoneutral environments has increased in recent decades. This paper examines evidence of historic changes in winter domestic temperatures in industrialised countries. Future trajectories for indoor thermal comfort are also explored. Whilst methodological differences across studies make it difficult to compare data and accurately estimate the absolute size of historic changes in indoor domestic temperatures, data analysis does suggest an upward trend, particularly in bedrooms. The variations in indoor winter residential temperatures might have been further exacerbated in some countries by a temporary drop in demand temperatures due to the 1970s energy crisis, as well as by recent changes in the building stock. In the United Kingdom, for example, spot measurement data indicate that an increase of up to 1.3°C per decade in mean dwelling winter indoor temperatures may have occurred from 1978 to 1996. The findings of this review paper are also discussed in the context of their significance for human health and well-being. In particular, historic indoor domestic temperature trends are discussed in conjunction with evidence on the links between low ambient temperatures, body energy expenditure and weight gain.

Epidemiology And Outcomes Of Radiator Burns At A High Throughput Burns Centre.

Indoor radiator burns can cause significant morbidity and mortality, especially in vulnerable patients. However, the epidemiology and clinical outcomes are poorly characterized. A retrospective study of all radiator burns referred to a tertiary regional burns centre between 2013-2019 was conducted. Four hundred and forty-seven patients (median age 25.6 years, male:female ratio 1.4:1) were referred; 109 (24%) admitted, 201 (45%) managed in outpatients and 137 (31%) managed locally. The incidence of burns leading to referral was 0.65/100,000/year, but increased annually. Contact burns consisted of 99.6%. Age distribution was bimodal: <5 years (43%), >65 years (27%), although all ages were affected. Median TBSA was 0.75% (0.1-11.5%), but 79% had injuries <2%. Childhood burns were predominantly superficial dermal grab injuries, usually manageable as outpatients. Elderly patients had larger burns usually secondary to falls or impaired sensorium, and were more likely to die (p<0.05). Burns due to impaired sensorium were deeper and more likely to require surgery (p<0.05). Sixty-three (14%) patients required surgery. Thirty-day mortality was 1.1%. Age was the only significant predictor of mortality. This study quantifies the epidemiology and outcomes of a growing problem. It identifies at risk populations (extremes of age), and important features of the clinical assessment.

Les brûlures en milieu clos liées à un radiateur peuvent être responsables de morbidités et de mortalité non négligeables, particulièrement chez les patients fragiles. Toutefois, l'épidémiologie et l'évolution en sont mal connues. Nous avons étudié rétrospectivement les 447 brûlures (âge médian des patients 25,6 ans ; 1,4 hommes pour 1 femme) liées à ces appareils adressées dans un CTB de référence entre 2013 et 2019. Parmi celles- ci, 109 (24%) ont été hospitalisées, 201 suivies par nous en externe et 137 (31%) pris en charge dans une structure non spécialisée. L'incidence annuelle est de 0,65/100 000/an, en augmentation régulière. Quasiment toutes (99,6%) sont dues à un contact. Bien que tous les âges puissent être affectés, on observe 2 pics d'incidence, avant 5 ans (43% des patients) et après 65 ans (27%). La surface atteinte s'étendait de 0,1 à 11,5% (médiane 0,75%), 79% des brûlures touchant moins de 2% SCT. Les enfants souffraient le plus souvent de brûlures superficielles, suivies en externe, après avoir empoigné le matériel. Chez les sujets âgés, les brûlures, consécutives à une chute ou à contact prolongé en raison de troubles sensoriels (ces dernières plus souvent profondes et nécessitant un traitement chirurgical ­ p< 0,05), sont plus étendues et plus souvent mortelles (p< 0,05). Soixante- trois (14%) patients ont eu besoin de chirurgie, la mortalité à 30 jours était de 1,1% ; l'âge étant le seul facteur prédictif de mortalité. Cette étude précise l'épidémiologie et l'évolution d'un problème émergeant, la population à risque (âges extrêmes) et met en avant certaines particularités cliniques.

Spatio-temporal analysis of urban air pollutants throughout China during 2014-2019.

Air pollution control has become the top priority of China's "green development" concept since 2013. The Chinese government has enacted a range of policies and statutes to control contaminant emissions and improve air quality. On the basis of the national air quality ground observation database, the spatial and temporal distribution of air quality index value (AQI), fine particulate matter (PM2.5), coarse particles (PM10), sulfur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO), and ozone (O3) were explored in 336 cities throughout China from 2014 to 2019. AQI and most pollutants (except O3) decreased in concentrations from 2014 to 2019. In 2019, all cities except Henan reached the level 2 of the ambient air quality index, and six cities had a lower ambient air quality index and reached the level 1. Spatially, higher pollutant concentrations were concentrated in large city clusters, whereas the areas with high O3 concentration were found across the country. Furthermore, central heating was shown to have a negative impact on air quality. The observed AQI value, PM2.5, PM10, SO2, NO2, and CO concentrations were highest in north and northwest China and Henan province in central China. The correlations among pollutants suggest that the main sources of pollutants are fossil fuel combustion, industrial production, and motor vehicle emissions. The influence of meteorological factors on air quality, long-distance transportation, and the transformations of pollutants should be explored in future research. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11869-021-01043-5.

Preservation of geochemical markers during co-combustion of hard coal and various domestic waste materials.

Combustion of domestic waste for heating purposes in non-adapted furnaces is a common environmental problem all over the world since it leads to significant emission of harmful substances to the atmosphere. In this project fly and bottom ash from hard coal and domestic waste co-combustion were investigated on the occurrence and distribution of geochemical markers, polycyclic aromatic hydrocarbons (PAHs), and their alkyl derivatives. Hard coal with a domestic waste admixture (paper, ethylene propylene diene rubber, tire rubber, polyethylene, polyvinyl chloride) was combusted in a certified domestic central heating furnace equipped with a control and measurement system. Fly ash was collected on glass microfiber filters inside the flue gas chimney. Raw fuels, fly and bottom ash extracts were analyzed with gas chromatography-mass spectrometry (GC-MS). Geochemical markers survived the coal/domestic waste combustion and can be identified despite the presence of other organic compounds derived from domestic waste thermal decay. The highest changes in distribution and values of geochemical ratios concern light-weight compounds, i.e. lighter n-alkanes and acyclic isoprenoids (pristane and phytane), with distinct differences between fly and bottom ash. n-Alkanes expulsion significantly decreased values of Pr/n-C17 and Ph/n-C18 ratios. Due to their high molecular weight pentacyclic triterpanes mostly retained their original distributions; however, some shifts in values of their thermal maturity ratios occurred due to artificial maturation of organic matter under the heat of combustion. PAHs diagnostic ratios showed variable utility in the indication of domestic waste admixture to hard coal combusted. The highest sensitivity was found for BaP/BghiP, MPI-1, and MPI-3 whereas Fl/(Fl + Py) rather pointed out at hard coal dominating in the fuel mixture. The addition of EPDM and tires significantly worsened the quality of combustion, which is reflected in high extract yields and the retained hard coal geochemical features such as the Pr/Ph value closest to the raw coal value.

Dose reduction of scattered photons from concrete walls lined with lead: Implications for improvement in design of megavoltage radiation therapy facility mazes.

PURPOSE: This study explores the possibility of using lead to cover part of the radiation therapy facility maze walls in order to absorb low energy photons and reduce the total dose at the maze entrance of radiation therapy rooms. METHODS: Experiments and Monte Carlo simulations were utilized to establish the possibility of using high-Z materials to cover the concrete walls of the maze in order to reduce the dose of the scattered photons at the maze entrance. The dose of the backscattered photons from a concrete wall was measured for various scattering angles. The dose was also calculated by the FLUKA and EGSnrc Monte Carlo codes. The FLUKA code was also used to simulate an existing radiotherapy room to study the effect of multiple scattering when adding lead to cover the concrete walls of the maze. Monoenergetic photons were used to represent the main components of the x ray spectrum up to 10 MV. RESULTS: It was observed that when the concrete wall was covered with just 2 mm of lead, the measured dose rate at all backscattering angles was reduced by 20% for photons of energy comparable to Co-60 emissions and 70% for Cs-137 emissions. The simulations with FLUKA and EGS showed that the reduction in the dose was potentially even higher when lead was added. One explanation for the reduction is the increased absorption of backscattered photons due to the photoelectric interaction in lead. The results also showed that adding 2 mm lead to the concrete walls and floor of the maze reduced the dose at the maze entrance by up to 90%. CONCLUSIONS: This novel proposal of covering part or the entire maze walls with a few millimeters of lead would have a direct implication for the design of radiation therapy facilities and would assist in upgrading the design of some mazes, especially those in facilities with limited space where the maze length cannot be extended to sufficiently reduce the dose.