RESUMO
The combined effects of heat events and poor air quality conditions can severely affect population health. A novel correlational method was developed to assess the impact of the short-term variations of environmental variables (air pollutants and ambient conditions) on community health responses (mortalities and emergency department visits). A multi-dimensional clustering approach was proposed by combining hierarchical and k-means clustering to promote flexibility and robustness to improve the correlation procedure. The study focused on the health records of the elderly population and people diagnosed with cardiorespiratory causes. The study investigated multiple health records on different levels of investigation: total, elderly, cause-based, and elderly cause-based records. The developed method was validated by investigating the short-term impact of ambient air temperature, relative humidity, ground-level ozone, and fine particulate matter on the health records during hot and warm seasons in the municipalities of Mississauga and Brampton, Peel Region, Ontario, Canada for 15 years. The analysis confirmed the association between moderate levels of environmental variables and increased short-term daily total deaths and emergency department visits, while the elderly sector showed higher vulnerability to environmental changes. Furthermore, the association with extreme heat conditions and poor air quality levels was affirmed with cause-based mortalities and emergency visits; the correlation was strongest with elderly cause-based health records. Findings confirm that cardiorespiratory patients, especially elderly people, were at the greatest risk of poor environmental conditions.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Ozônio , Humanos , Idoso , Dióxido de Nitrogênio/análise , Temperatura Alta , Poluição do Ar/análise , Poluentes Atmosféricos/toxicidade , Poluentes Atmosféricos/análise , Material Particulado/toxicidade , Material Particulado/análise , Ozônio/toxicidade , Ozônio/análise , Estações do Ano , Serviço Hospitalar de Emergência , Ontário/epidemiologiaRESUMO
Enhancing the thermal comfort of low-income housing in developing countries located in tropical areas is one of the main challenges for engineers and architects worldwide. The coconut mesocarp fibre (coir) has shown enormous potential for improving some properties of modified concretes or mortars, such as low-weight and high-acoustic isolation. In this study, the potential use of modified mortars by coconut fibres as a facade coating layer to enhance thermal comfort in low-income housing structures was evaluated for the city of Cartagena de Indias, Colombia. An actual typical low-income house of 42 m2 was monitored. Temperature and humidity variations were monitored for 39 days, thermal characteristics of coir-modified mortars were also investigated using differential scanning calorimetry (DSC) and an adaptation of the standard test method of the guarded-hot-cartridge apparatus. The EnergyPlus™ software was used to simulate indoor temperature variations in the studied house. Results show that during the period of 4 h of maximum sunlight radiation with outdoor temperatures in the range of 29-34 °C, coating the cement-sand hollow block structure with a layer of coir-modified mortar could reduce indoor room temperatures by 0.5-1.5 °C, approximately. Thus, there is a potential to enhance the thermal comfort in low-income housing structures with coconut fibre modified mortars while reducing annual energy costs of cooling by 16%, making it affordable for low-income families in the Caribbean region of Colombia.
Assuntos
Cocos , Habitação , Região do Caribe , Cidades , ColômbiaRESUMO
It is desirable to develop novel multipurpose phase change materials (PCMs) with improved energy storage and release characteristics. In this study, the utility of a nanocomposite composed of a metal-organic framework (MOF) and graphite was explored for shape-stable PCMs. The prepared MOF-integrated graphite featured favorable structural characteristics (such as large specific surface area (550.6 m2/g), increased total pore volume, and dominant mesopore structure). The obtained composite with a high energy storage capacity (111.4 J/g) exhibited an electrical resistivity that was at least 7 orders of magnitude lower than that of the pristine PCM. In addition, the alkane possessed enhanced chemical compatibility with the supporting scaffolds, outstanding shape, and thermal stabilities. The strong structural connectivity, high specific surface area, and pore size distributions (micro/mesopores) of the scaffolds play a remarkable role in large PCM infiltration ratio, high electrical conductivity, and improved thermal properties of as-prepared composites. It was also suggested that the cavities of the MOF, filled with graphite and the π-π interactions between strand ligands, generate favorable pathways in the nanocomposites. Subsequently creates a supramolecular "wire-like" paths and reduce the resistivity of the parent materials. Therefore, this multifunctional material shows the potential for applications in electro/thermal energy management systems.
RESUMO
Given the large transformation and fast-growing population that the Greater Toronto Area (GTA) is facing, and the increasing impact of climate change in urbanized areas, it is crucial to investigate strategies that could mitigate the effects of heat waves. In this paper, the effects of greenery enhancements are investigated using mesoscale and microscale simulations performed by the Weather Research and Forecasting model and the ENVI-met model, respectively. In particular, two vulnerable areas located in the GTA are investigated. Comparing the results of simulations with measurements show the differences in how mesoscale and microscale models predict the meteorological processes happening within the urban canopy and the local climate. Then, two mitigation scenarios, a moderate green scenario (MGS) and an intensive green scenario (IGS) are assessed considering different increases in the vegetation area. The results of the mesoscale simulations show that by increasing the greenery canopy, the maximum daily air temperature decreases by 1.6 to 2.3 °C, while the relative humidity increases by 10% to 12%. The microscale simulations show that increasing the tree canopy would cool the air temperature by 0.5 °C to 1.4 °C locally. Overall, depending on wind conditions and the arrangement of buildings and existing green areas, the cooling effect is shown to have an impact on up to 250 m downwind from the new green area locations. Finally, this study demonstrates that both mesoscale (WRF) and microscale (ENVI-met) modeling confirm similar results in how greenery enhancements may improve the human thermal comfort in the continental climate of the GTA.
Assuntos
Temperatura Alta , Meteorologia , Cidades , Humanos , Temperatura , Tempo (Meteorologia) , VentoRESUMO
Aerogel is a superinsulating material with an extremely low thermal conductivity (<0.015 W/m·K), high porosity (>99 %), and extremely low density. In this study, a new closed-cell spray polyurethane (PU) foam with aerogel was developed and investigated. In particular, a PU foam with aerogel and graphite (PUAG) was prepared by mixing aerogel for reducing the thermal conductivity of the foam and a small concentration of graphite for improving its flame-retardancy performance. The performance of the prepared PUAG was analyzed via several tests, including density measurements, thermal-conductivity measurements, morphology examination, flame-retardancy evaluation, thermogravimetric analysis, and dynamic heat transfer analysis. A 20 % reduction in the thermal conductivity compared with traditional PU was observed. Additionally, the PUAG exhibited a reduction in the total smoke production and a 10 % reduction in the surface peak temperature.
RESUMO
The increase in coffee consumption has led to increased production of coffee waste. Methods to recycle coffee waste are constantly being researched. Coffee powder is a porous material that can effectively be used to absorb sound. In this study, sound-absorbing panels were developed using coffee waste combined with resin. A sound absorption characterization of the new material was performed. Then, the noise reduction potential using coffee-waste sound absorbers was investigated in cafés. A café has several noise sources, such as coffee machines, music, and the voices of people. The noise reduction effect was evaluated using the ODEON simulation software together with the improvement in both the clarity and reverberation time in a case study café. In the investigated room, the acoustic definition (D50) increased up to 0.8, while the reverberation time (RT) reduced to 0.6 s. The results of this study demonstrate that the noise generated in the café was reduced by recycling the coffee waste produced as a by-product in the same building. Finally, this study presents a new construction material manufactured through coffee waste that is in turn applied to cafés where the coffee waste itself is produced.
Assuntos
Café , Reciclagem , Materiais de Construção , Ruído , PorosidadeRESUMO
In addition to the mitigation of carbon emissions through the reduction of building energy consumption, the prevention of fire spread in buildings is important an important task globally. Therefore, a growing interest towards building materials that can simultaneously contribute to energy savings and provide good flame-retardant performance in buildings exist. The flame-retardant performances of buildings can be improved through the use of inorganic building materials during construction. Meanwhile, among the different types of construction waste, more than 70% of ceramics can be recycled, which would reduce carbon emissions in the production process. Ceramics are inorganic and non-flammable, and can thus secure the flame-retardant performance of buildings. In this study, recycled ceramic-based inorganic insulation to secure the flame-retardant performance of a building are analyzed for their energy saving values. A case study building was modeled and the flame-retardant performance and building energy consumption were analyzed. Setting the thermal transmittance of the external wall according to the energy conservation design standards in South Korea, the tradeoff between model calculates annual energy consumption fire protection and minimization of material environmental impacts are discussed. As a result of simulation, when a wall constructed according to the energy conservation design standards of buildings, the building energy was saved by 18.6% and fire resistance performance was secured.
Assuntos
Cerâmica/análise , Materiais de Construção/análise , Retardadores de Chama/análise , Reciclagem , República da CoreiaRESUMO
The rapid urban expansion in East-Asian cities has increased the need for comfortable public spaces. This study presents field measurements and parametric simulations to evaluate the microclimatic characteristics in a university campus in the tropical climate of Kuala Lumpur, Malaysia. The study attempts to identify the thermally uncomfortable areas and their physical and design characteristics while debating on the circumstances of enhancing the outdoor comfort conditions for the campus users. Simulations in Envi-met and IES-VE are used to investigate the current outdoor thermal conditions, using classic thermal metric indices. Findings show high levels of thermal discomfort in most of the studied spaces. As a result, suggestions to improve the design quality of outdoor areas optimizing their thermal comfort conditions are proposed. The study concludes that effective re-design of outdoor spaces in the tropics, through adequate attention to the significant impacts of shading and vegetation, can result in achieving outdoor spaces with high frequency of use and improved comfort level.
Assuntos
Ambiente Construído , Temperatura Alta , Microclima , Meio Ambiente , Malásia , Clima Tropical , UniversidadesRESUMO
Different models to improve prediction of energy-based acoustic parameters in churches have been proposed by different researchers [E. Cirillo and F. Martellotta, J. Acoust. Soc. Am. 118, 232-248 (2005); T. Zamarreño et al., J. Acoust. Soc. Am. 121, 234-250 (2006)]. They all suggested variations to the "revised" theory proposed by Barron and Lee [J. Acoust. Soc. Am. 84, 618-628 (1988)], starting from experimental observations. The present paper compares these models and attempts to generalize their use taking advantage of the measurements carried out in 24 Italian churches differing in style, typology, and location. The whole sample of churches was divided into two groups. The first was used to fine-tune existing models, with particular reference to the "mu model," which was originally tested only on Mudejar-Gothic churches. Correlations between model parameters and major typological and architectural factors were found, leading to a classification that greatly simplifies parameter choice. Finally, the reliability of each model was verified on the rest of the sample, showing that acoustic parameters can be predicted with reasonable accuracy provided that one of the specifically modified theories is used. The results show that the model requiring more input parameters performs slightly better than the other which, conversely, is simpler to apply.