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1.
J Environ Manage ; 267: 110655, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421680

RESUMO

Assessing the thermal comfort of the car in a hot and humid climate is crucial as it may have adverse health implications. In the current study, different models of car were used to conduct real-time monitoring of temperature and relative humidity (RH %) inside the car cabin to assess the thermal comfort of a virtual occupant. The temperature in car cabins during the monitoring period ranged between 26.7 and 64.9 °C while the range of RH was 8.3-60.4%. Data from meteorological stations were also collected to develop a scenario of thermal comfort of occupants outside the car in standing position. The PMV range as per ASHRAE 55-2017 guidelines for ambient conditions was 3.24-7.41, the car front was 8.36-11.87, and the car back was 11.5-18.04. The thermal comfort sensation was found to be hot in all instances and followed category IV of EN15251 guidelines. PMV was observed to be worst for Sedan for both front and back as per both ASHRAE 55-2015 and EN12521 guidelines. The PPD was observed to be 100% in all cases, showing dissatisfaction for all car models. The concentration of CO2 and CO ranged between 113-1127 ppm and 0-3.9 ppm, respectively, for the front of the car. The results were also compared with the threshold values of thermal comfort parameters according to ISHRAE Standard 10,001:2016 and found to be acceptable. Climate change is leading to extremes in temperature, this may impact the thermal comfort of the car occupants to a great extent due to the heating of the car cabins, which act as a closed microenvironment. Hence, the current study urges to formulate guidelines for car design based on thermal comfort and developing a sensor to indicate thermal comfort for occupants to avoid adverse health impacts in the hot climate.


Assuntos
Calor Extremo , Clima Tropical , Automóveis , Calefação , Temperatura , Sensação Térmica
2.
Waste Manag ; 106: 226-239, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32240939

RESUMO

In the context of waste upgrading of polyethylene terephthalate (PET) by pyrolysis, this study presents three on-line mass spectrometric techniques with soft ionization for monitoring the emitted decomposition products and their thermal dependent evolution profiles. Pyrolysis experiments were performed using a thermogravimetric analyzer (TGA) under nitrogen atmosphere with a heating rate of 5 °C/min from 30 °C to 600 °C. Single-photon ionization (SPI at 118 nm/10.5 eV) and resonance enhanced multiple photon ionization (REMPI at 266 nm) were used with time-of-flight mass spectrometry (TOF-MS) for evolved gas analysis (TGA-SPI/REMPI-TOFMS). Additionally, the chemical signature of the pyrolysis products was investigated by atmospheric pressure chemical ionization (APCI) ultra high resolution Fourier Transform ion cyclotron resonance mass spectrometry (FT-ICR MS) which enables assignment of molecular sum formulas (TGA-APCI FT-ICR MS). Despite the soft ionization by SPI, the fragmentation of some compounds with the loss of the [O-CH = CH2] fragment is observed. The major compounds were acetaldehyde (m/z 44), benzoic acid (m/z 122) and a fragment of m/z 149. Using REMPI, aromatic species were selectively detected. Several series of pyrolysis products were observed in different temperature intervals, showing the presence of polycyclic aromatic hydrocarbons (PAHs), especially at high temperatures. FT-ICR MS data showed, that the CHO4 class was the most abundant compound class with a relative abundance of 45.5%. The major compounds detected with this technique corresponded to m/z 193.0495 (C10H9O4+) and 149.0233 (C8H5O3+). Based on detailed chemical information, bulk reaction pathways are proposed, showing the formation of both cyclic monomer/dimer and linear structures.


Assuntos
Hidrocarbonetos Policíclicos Aromáticos , Polietilenotereftalatos , Calefação , Espectrometria de Massas , Pirólise
3.
Waste Manag ; 106: 145-154, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32217443

RESUMO

Crushing is the key part for the recycling technology of waste printed circuit boards (WPCBs). In this study, the breakage and liberation effects of WPCBs was improved by heat pretreatment technology before crushing (HPBC). Based on the test results, 200 °C was found as the safe temperature for the HPBC of WPCBs. The fracture mode, particle size distribution, and enrichment characteristics of WPCBs were systematically studied. The experimental results show that the HPBC changed the breakage mode from longitudinal fracture to horizontal fracture and improved the liberation of metal from non-metal components. During the crushing process, the increase in the heat pretreatment time (30-120 min) and temperature (100-200 °C) can improve the crushing effect of WPCBs and increase the content of crushing products of -0.3 mm by 3.16% and 5.64%, respectively. Compared to the non-metallic components, the metal components have ductility and are difficult to break into -0.3 mm during the crushing process. HPBC can promote copper enrichment to narrow grain size. In the 0.3-1 mm range, the content of copper increased from 47.87% to 57.61%, an increase by 9.74%. The initial enrichment of copper was achieved by adjusting the crushing time. The recovery rate of copper can reach 85.66%, and the enrichment rate is 1.74 when 0.3-2 mm breaking product is used as enrichment. Therefore, HPBC can effectively improve the crushing and liberation effect of WPCBs and improve the enrichment rate, and thus is an effective pretreatment method.


Assuntos
Resíduo Eletrônico , Cobre , Calefação , Metais , Reciclagem
4.
Food Chem ; 317: 126447, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32092610

RESUMO

The inhibitory effect of caffeic acid on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) was investigated in chemical model systems under microwave heating (MW). A mechanistic study was subsequently carried out to identify the inhibitory mechanism. The results showed that both for conductive heating (CV) and MW, the inhibition of PhIP increased with the concentration of caffeic acid but decreased with the prolongation of heating time. The inhibition on PhIP under MW was always higher than under CV, which were dominated by the difference in dielectric loss (ε″). UPLC-MS analysis showed that caffeic acid releases a CO2 molecule to produce 4-vinylcatechol which can form adducts with phenylacetaldehyde, thus reducing its availability for PhIP formation. The structure of adduct was characterized as 3-(3,4-dihydroxyphenyl)-2-phenylbutanal with a molecular weight of 256. The findings indicate that trapping of phenylacetaldehyde by 4-vinylcatechol is a key mechanism of caffeic acid in inhibiting PhIP formation.


Assuntos
Ácidos Cafeicos/química , Imidazóis/química , Micro-Ondas , Acetaldeído/análogos & derivados , Acetaldeído/química , Carcinógenos/química , Cromatografia Líquida , Fenômenos Eletromagnéticos , Calefação , Espectrometria de Massas , Mutagênicos/química , Fatores de Tempo
5.
Bioresour Technol ; 302: 122843, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32006926

RESUMO

The composite catalysts were synthesized with SiC powder and ZSM-5 and were characterized by Brunauer-Emmett-Teller, X-ray diffraction, thermogravimetric analysis, pyridine-infrared spectroscopy, and scanning electron microscopy. The catalysts showed a high heating rate and excellent catalytic performance for pyrolysis vapors, and the product fractional distribution and chemical compositions of bio-oil in a tandem system (microwave pyrolysis and microwave ex-situ catalytic reforming) was examined. Experimental results confirmed the quality of bio-oil produced by the microwave-induced catalytic reforming was better than that product through electric heating. Additionally, 36.94 wt% of bio-oil was obtained using the catalyst with 20%ZSM-5/SiC under the following conditions: feed-to-catalyst ratio, 2:1; pyrolysis temperature, 550 °C; and catalytic temperature, 350 °C. The selectivities of hydrocarbons reached up to 75.88%. After five cycles, the activity of the regenerated composite catalyst was retained at 95% of the original catalyst.


Assuntos
Micro-Ondas , Soja , Biocombustíveis , Catálise , Calefação , Temperatura Alta , Óleos Vegetais , Polifenóis , Pirólise
6.
Int Endod J ; 53(5): 698-708, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31955442

RESUMO

AIM: To investigate the chemical changes affecting different types of gutta-percha and endodontic sealers during heating, and correlate changes with the heating capacity of different heat carriers. METHODOLOGY: The heating capacity of three endodontic heat carriers was evaluated using thermocouples to produce heat profiles. The devices were activated at different temperature set-ups, in continuous or cut-out modes. Chemical changes of six brands of gutta-percha and four types of sealers were assessed in real time during heating using micro-Raman spectroscopy equipped with a heating stage. Raman spectra of each tested material were averaged and compared at different temperature levels. The sealers were further assessed by Fourier transform infrared (FT-IR) spectroscopy. RESULTS: None of the tested heat carriers achieved the temperature levels that were set by the devices and recommended by the manufacturer. The use of continuous heating mode resulted in higher rises in temperature than the 4 s cut-out mode that reached 110 °C. The various brands of gutta-percha exhibited different chemical changes in response to heat. Some changes even occurred below temperature levels generated by the heating devices. All sealers revealed changes in their chemical composition upon heating. Changes in epoxy resin- and zinc oxide-eugenol-based sealers were detectable at 100 °C, with structural alterations beyond that temperature and irreversible changes after cooling. Water loss was irreversible in BioRoot, but its chemical structure was stable as well as for the TotalFill. CONCLUSIONS: The heating capacity of endodontic heat carriers needs to be standardized, so that the temperatures delivered by the tips are the same as that set on the dial. Practitioners should be aware of the actual temperatures generated by these devices, and the suitability of sealers to be used at the temperature levels achieved.


Assuntos
Materiais Restauradores do Canal Radicular , Compostos de Cálcio , Resinas Epóxi , Guta-Percha , Calefação , Teste de Materiais , Obturação do Canal Radicular , Silicatos , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
7.
Waste Manag ; 103: 240-250, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31901617

RESUMO

Management of solid recovered fuel (SRF) in South Korea is unique from most other countries in that it is based on a single standard. All SRFs are distributed at the same price irrespective of their performance, resulting in utilization problems and a low degree of acceptance among consumers. Moreover, the difficulty of temperature maintenance during transportation, excessive ash content, and the use of inappropriate microwave acid digestion methods pose challenges to SRF reliability. To address these issues, we compared the relevant management statuses in South Korea with those of the international community and reviewed the effects of the transportation temperature, ash content, and microwave acid digestion technique. The moisture, ash, sulfur, and chlorine contents as well as the lower heating values (LHVs) of all the samples from South Korea were found to be below the standard [international] thresholds, and they were barely influenced by the transportation temperature. In addition, 5 g samples were found to be more appropriate for ash content analysis than the 20 g samples used in South Korea, with the former producing smaller standard deviations. The optimal microwave acid digestion conditions were also determined to be a reaction time with nitric acid of >10 min, temperature of 180 °C, and microwave power of 600 W. The results of this study highlight the need for revising the SRF test methods used in South Korea, to boost the market and enhance quality reliability.


Assuntos
Eliminação de Resíduos , Cloro , Calefação , Reprodutibilidade dos Testes , República da Coreia
8.
Waste Manag Res ; 38(1_suppl): 77-85, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31957598

RESUMO

In this work, the pyrolysis behavior of plastic waste-TV plastic shell-was investigated, based on thermogravimetric analysis and using a combination of model-fitting and model-free methods. The possible reaction mechanism and kinetic compensation effects were also examined. Thermogravimetric analysis indicated that the decomposition of plastic waste in a helium atmosphere can be divided into three stages: the minor loss stage (20-300°C), the major loss stage (300-500°C) and the stable loss stage (500-1000°C). The corresponding weight loss at three different heating rates of 15, 25 and 35 K/min were determined to be 2.80-3.02%, 94.45-95.11% and 0.04-0.16%, respectively. The activation energy (Ea) and correlation coefficient (R2) profiles revealed that the kinetic parameters calculated using the Friedman and Kissinger-Akahira-Sunose method displayed a similar trend. The values from the Flynn-Wall-Ozawa and Starink methods were comparable, although the former gave higher R2 values. The Eα values gradually decreased from 269.75 kJ/mol to 184.18 kJ/mol as the degree of conversion (α) increased from 0.1 to 0.8. Beyond this range, the Eα slightly increased to 211.31 kJ/mol. The model-fitting method of Coats-Redfern was used to predict the possible reaction mechanism, for which the first-order model resulted in higher R2 values than and comparable Eα values to those obtained from the Flynn-Wall-Ozawa method. The pre-exponential factors (lnA) were calculated based on the F1 reaction model and the Flynn-Wall-Ozawa method, and fell in the range 59.34-48.05. The study of the kinetic compensation effect confirmed that a compensation effect existed between Ea and lnA during the plastic waste pyrolysis.


Assuntos
Plásticos , Pirólise , Calefação , Cinética , Termogravimetria
9.
Environ Sci Technol ; 54(3): 1867-1877, 2020 02 04.
Artigo em Inglês | MEDLINE | ID: mdl-31934752

RESUMO

This study reports distillation-based salt removal by Ohmic heating in a hybrid process, in which electrochemical oxidation (EO) and direct contact membrane distillation (DCMD) are performed sequentially. In addition to anodically destructing the organics, the hybrid process also separated the sulfate-based electrolytes from treated water through distillation, without consuming external energy, owing to the temperature of the aqueous sulfate solution being elevated to 70 °C via resistive heating. The hybrid process treated organic compounds in a nonselective fashion, whereas DCMD alone did not completely reject (semi)volatile organics. Integrating EO with DCMD made the hybrid process resistant toward the wetting phenomenon; the process exhibited a steady distillate flux and salt rejection as the initial loading of amphiphilic sodium dodecyl sulfate was increased to 0.3 mM. Anodic persulfate formation from the sulfate and Ohmic heating caused an in situ yield of the sulfate radical in the feed solution; this eliminated membrane fouling, according to the observation that the water flux, which was drastically reduced upon adding alginate, was recovered immediately after an electric current was applied. The hybrid process concurrently decomposed spiked organics and removed naturally present inorganic ions in actual flue gas desulfurization wastewater, without an external supply of electrolyte and heat energy.


Assuntos
Destilação , Purificação da Água , Impedância Elétrica , Calefação , Membranas Artificiais
10.
Environ Sci Pollut Res Int ; 27(8): 8285-8307, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31900771

RESUMO

Self-heating occurring was studied in the Bytom coal-waste dump using petrographic, mineralogical, and organic geochemical to assess the changes induced by heating on organic material and quantify-qualify the emitted gases. The distribution of geochemical markers such as n-alkanes, alkylbenzenes, alkylcyclohexanes, phenols, sulfurous compounds, and emitted gases in the waste dump is outlined. Heating of organic material there is indicated by high vitrinite random reflectance (Rr)% values that typically characterize samples with short-chain n-alkanes, alkylbenzenes, and alkylmethylbenzenes. Contents of minerals showing minor alterations are high with ~ 90% in burned-out samples. Inside the dump where temperatures can reach up to 700-1300 °C and oxygen contents are significantly reduced, conditions favor coking. This situation is confirmed by the formation of enormous quantities of phenols and alkylbenzenes or by elevated amounts of H2 formed under low-oxygen conditions (pyrolysis). Aromatization, pyrolysis (thermal cracking), and oxidation are associated with the heating in the dump. Gases such as methane, ethane, propane, and ethylene formed during self-heating can serve as fuel for the fire inside the dump, in the process generating huge amounts of CO2.


Assuntos
Carvão Mineral , Calefação , Carvão Mineral/análise , Oxigênio/química , Polônia , Instalações de Eliminação de Resíduos
11.
J Environ Manage ; 256: 109947, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31989979

RESUMO

In this research, ammonia evaporation capacity under atmospheric and vacuum pressure conditions, as well as distillation capacity of different concentrations of landfill leachates, were evaluated. Simple evaporation and vacuum pressure evaporation tests showed high NH3-N removal efficiencies, ranging from 95% to 98% for raw landfill leachates, indicating that vacuum pressure would not be necessary during ammonia removal and recovery processes when applying temperature of 300 °C. Distillations tests also showed the promising NH3-N recovery potential in ultra-concentrated leachates (over 100 gNH3-N/L) in the order of 91%-94% in few minutes, evaporating a small portion of landfill leachate. The results presented encourages the recovery of ammonia from landfill leachate and its industrial and agricultural, highlighting its feasibility as well as simultaneously preventing the ammonia release to water bodies or the atmosphere.


Assuntos
Amônia , Poluentes Químicos da Água , Calefação , Nitrogênio , Temperatura
12.
Waste Manag Res ; 38(2): 202-212, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31405341

RESUMO

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin-1, 10°Cmin-1, 15°Cmin-1 and 20°Cmin-1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats-Redfern) and model free methods (Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats-Redfern, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunose and Friedman models were found in the ranges 105-148.48 kJmol-1, 99.41-140.52 kJmol-1, 103.67-149.15 kJmol-1 and 99.93-141.25 kJmol-1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.


Assuntos
Poliestirenos , Resíduos Sólidos , Calefação , Cinética , Termogravimetria
13.
N Z Vet J ; 68(2): 126-133, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31608795

RESUMO

Case history: Gradual onset of ocular opacity was observed in three gold-striped geckos (Woodworthia chrysosiretica), and five Pacific geckos (Dactylocnemis pacificus) held in two adjacent terrariums in a zoological institution located in the North Island of New Zealand. Ultraviolet light and heat had been provided for the previous 3-4 years by a fluorescent bulb, but in the last 4 weeks of winter a ceramic heat bulb had been added, situated 10 cm above the upper mesh of the cageClinical findings: All eight geckos presented with mostly bilateral lesions of varying severity confined to the central or upper quadrant of the spectacles. These lesions ranged from variable areas of opacity within the stroma of the spectacle to similarly distributed ulcers of the surface epithelium of both spectacles. The spectacle lesions in the Pacific geckos responded well to treatment with topical combined antimicrobial therapy, within 18-29 days. The gold-striped geckos suffered complications including dysecdysis, severe spectacle ulceration and perforation, mycotic spectaculitis, and widespread mycotic dermatitis resulting in death or leading to euthanasia.Pathological findings: In the three gold-striped geckos, there were extensive areas of deep ulceration and replacement of the spectacle with a thick serocellular crust containing large numbers of fungal elements. The affected areas of the stroma were expanded by large deposits of proteinaceous and mucinous material, pyknotic cellular debris and moderate numbers of heterophils and macrophages as well as infiltrating fungal hyphae.Diagnosis: Mycotic spectaculitis with ulceration and perforation, and disseminated mycotic dermatitis likely secondary to thermal burns.Clinical relevance: This is the first report of thermal burns of the spectacle in any reptile. There was species variation in the burn severity with gold-striped geckos showing more severe lesions, possibly due to a mix of behavioural and anatomical factors. The thermal burns to the spectacles in three cases were complicated by delayed healing, perforation, dysecdysis and severe mycotic infection.


Assuntos
Queimaduras/veterinária , Oftalmopatias/veterinária , Calefação/instrumentação , Abrigo para Animais , Lagartos , Animais , Animais de Zoológico , Anti-Infecciosos/administração & dosagem , Anti-Infecciosos/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Bacitracina/administração & dosagem , Bacitracina/uso terapêutico , Queimaduras/etiologia , Combinação de Medicamentos , Oftalmopatias/etiologia , Oftalmopatias/patologia , Meloxicam/uso terapêutico , Neomicina/administração & dosagem , Neomicina/uso terapêutico , Polimixina B/administração & dosagem , Polimixina B/uso terapêutico , Raios Ultravioleta
14.
Bioresour Technol ; 297: 122480, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31812912

RESUMO

Microwave-assisted pyrolysis of waste suffers from the problem that the waste generally has low microwave absorptivity thereby resulting in low heating rate and low pyrolysis temperature. In this case, fast microwave-assisted pyrolysis is proposed and developed to help the pyrolysis of waste. This study describes two methods that can be used to realize fast microwave-assisted pyrolysis of waste: (1) premixed method (wastes are mixed with microwave absorbent) and (2) non-premixed method (wastes are poured onto the heated microwave absorbent bed). Then, biofuels (bio-oil, bio-gas, and bio-char) produced from fast microwave-assisted pyrolysis of wastes are reviewed. The review results show that the yields of bio-oil, bio-gas, and bio-char obtained from fast microwave-assisted pyrolysis of wastes varied significantly in the ranges of 2-96 wt%, 2.4-86.8 wt%, and 0.3-83.2 wt%, respectively. Although the present research focused mainly on the premixed method, non-premixed/continuous fast microwave-assisted pyrolysis is still promising and challenging.


Assuntos
Biocombustíveis , Micro-Ondas , Calefação , Temperatura Alta , Pirólise
15.
Waste Manag ; 102: 270-280, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31698229

RESUMO

Solid recovered fuel (SRF) has the characteristics of high calorific value and low chlorine and mercury content. The thermal decomposition of SRF collected from a municipal solid waste (MSW) incineration power plant in Hangzhou was investigated in this study. The study exhibits far-reaching significance for the design and commercial operation of SRF pyrolysis facilities and circulating fluidized bed (CFB) power plants. The pyrolysis behavior of SRF and its sorted components was evaluated by thermogravimetric analysis (TG). Five heating rates of 10, 15, 20, 25 and 30 °C·min-1 were conducted to analyze the effect of heating rate. The interactive effect of the sorted components was discussed by comparing the experimental and theoretical curves. Furthermore, the kinetic parameters were determined by using the Coats-Redfern (CR), Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods. The activation energies of SRF and its sorted components in the pyrolysis process were obtained. The main reaction stages of the SRF and its sorted components were described by different mechanism functions. However, it was found that the KAS and FWO methods were not applicable for SRF according to the comparison results. The results provide useful information for the design and commercial operation of SRF pyrolysis facilities and CFB power plants.


Assuntos
Incineração , Resíduos Sólidos , Calefação , Cinética , Termogravimetria
16.
Environ Pollut ; 256: 113055, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31744686

RESUMO

Little is known about fine particulate matter (PM2.5) exposure among pregnant women in rural China. This study aims to characterize exposure to PM2.5 among pregnant women in rural China, and investigate potential risk factors of personal exposure to PM2.5. The data were obtained from a birth cohort study that enrolled 606 pregnant women in Xuanwei, a county known for its high rates of lung cancer. The personal exposure to PM2.5 was measured using small portable particulate monitors during each trimester of pregnancy. Participants were interviewed using structured questionnaires that sought information on risk factors of PM2.5 exposure. The daily exposure to PM2.5 among the pregnant women ranged from 19.68 to 97.08 µg/m3 (median = 26.08). Exposure to PM2.5 was higher in winter and autumn than other seasons (p < 0.05); higher during the day than during the night (p < 0.001); and greater during cooking hours than during the rest of the day (p < 0.001). Using a mixed effects model, domestic solid fuel for cooking (ß = 1.75, p < 0.001), winter and autumn (ß = 2.96, p < 0.001), cooking ≥ once per day (ß = 1.58, p < 0.05), heating with coal (ß = 1.69, p < 0.001), secondhand smoke exposure (ß = 1.59, p < 0.001) and township 1(ß = 2.39, p < 0.001) were identified as risk factors for personal exposure to PM2.5 of pregnant women throughout pregnancy. Indirect effects of season and township factors on personal PM2.5 exposure were mediated by heating, cooking and domestic fuel using. In conclusion, PM2.5 levels in Xuanwei exceeded WHO guidelines. Seasonal and township factors and individual behaviors like domestic solid fuel using for cooking, heating with coal and secondhand smoke exposure are associated with higher personal PM2.5 exposure among pregnant women in rural China.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental/métodos , Exposição por Inalação/análise , Exposição Materna , Material Particulado/análise , Adulto , China , Carvão Mineral/análise , Estudos de Coortes , Culinária , Feminino , Calefação , Humanos , Gravidez , Trimestres da Gravidez , População Rural , Estações do Ano , Inquéritos e Questionários , Adulto Jovem
17.
Chem Biol Interact ; 315: 108887, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31705857

RESUMO

AIM: To investigate the molecular, structural, and functional impact of aerosols from candidate modified risk tobacco products (cMRTP), the Carbon Heated Tobacco Product (CHTP) 1.2 and Tobacco Heating System (THS) 2.2, compared with that of mainstream cigarette smoke (CS) on the cardiovascular system of ApoE-/- mice. METHODS: Female ApoE-/- mice were exposed to aerosols from THS 2.2 and CHTP 1.2 or to CS from the 3R4F reference cigarette for up to 6 months at matching nicotine concentrations. A Cessation and a Switching group (3 months exposure to 3R4F CS followed by filtered air or CHTP 1.2 for 3 months) were included. Cardiovascular effects were investigated by echocardiographic, histopathological, immunohistochemical, and transcriptomics analyses. RESULTS: Continuous exposure to cMRTP aerosols did not affect atherosclerosis progression, heart function, left ventricular (LV) structure, or the cardiovascular transcriptome. Exposure to 3R4F CS triggered atherosclerosis progression, reduced systolic ejection fraction and fractional shortening, caused heart LV hypertrophy, and initiated significant dysregulation in the transcriptomes of the heart ventricle and thoracic aorta. Importantly, the structural, functional, and molecular changes caused by 3R4F CS were improved in the smoking cessation and switching groups. CONCLUSION: Exposure to cMRTP aerosols lacked most of the CS exposure-related functional, structural, and molecular effects. Smoking cessation or switching to CHTP 1.2 aerosol caused similar recovery from the 3R4F CS effects in the ApoE-/- model, with no further acceleration of plaque progression beyond the aging-related rate.


Assuntos
Aerossóis/efeitos adversos , Apolipoproteínas E/metabolismo , Carbono/efeitos adversos , Sistema Cardiovascular/efeitos dos fármacos , Fumaça/efeitos adversos , Produtos do Tabaco/efeitos adversos , Tabaco/efeitos adversos , Animais , Aorta Torácica/efeitos dos fármacos , Aterosclerose/metabolismo , Sistema Cardiovascular/metabolismo , Feminino , Calefação/efeitos adversos , Exposição por Inalação/efeitos adversos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Camundongos , Fumar/efeitos adversos , Transcriptoma/efeitos dos fármacos
18.
Water Res ; 169: 115245, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31707176

RESUMO

Real-time monitoring of subsurface temperature profiles is a promising approach to resolving natural source zone depletion (NSZD) rates for shallow petroleum liquids. Herein, a new "single stick" computational method for transforming temperature data into NSZD rates is advanced. The method is predicated on subsurface temperatures being a function of surface heating and cooling, and the heat associated with NSZD. Given subsurface temperature at two points, a system of two-equation two-unknown is used to resolve NSZD rates. Mathematical formulations and computational algorithms are validated through computational tests showing near perfect agreement between prescribed and predicted NSZD heating, and observed and predicted subsurface temperatures. The method is applied to temperature data from five field sites. Results include lower NSZD rates in areas where petroleum liquids are absent by a factor of 0.5-7.5 as compared to background correction methods. While the single stick method provides the lowest rate in unimpacted areas, it also provides reasonable rates as compared to two of three background correction methods. In addition, the single stick method yields a coefficient of variation equal to 6% in a triplicate analysis and reasonable estimates of NSZD in LNAPL-impacted areas without background corrected data.


Assuntos
Poluição por Petróleo , Petróleo , Calefação , Temperatura Alta , Temperatura
19.
Waste Manag Res ; 38(3): 271-278, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31599207

RESUMO

Thermal treatment offers advantages of significant volume reduction and energy recovery for the polyurethane foam from waste refrigerators. In this work, the pyrolysis kinetics of polyurethane foam was investigated using the model-fitting, model-free and distributed activation energy model methods. The thermogravimetric analysis indicated that the polyurethane foam decomposition could be divided into three stages with temperatures of 38°C-400°C, 400°C-550°C and 550°C-1000°C. Peak temperatures for the major decomposition stage (<400°C) were determined as 324°C, 342°C and 344°C for heating rates of 5, 15 and 25 K min-1, respectively. The activation energy (Eα) from the Friedman, Flynn-Wall-Ozawa and Tang methods increased with degree of conversion (α) in the range of 0.05 to 0.5. The coefficients from the Flynn-Wall-Ozawa method were larger and the resulted Eα values fell into the range of 163.980-328.190 kJ mol-1 with an average of 206.099 kJ mol-1. For the Coats-Redfern method, the diffusion models offered higher coefficients, but the E values were smaller than that from the Flynn-Wall-Ozawa method. The Eα values derived from the distributed activation energy model method were determined as 163.536-334.231 kJ mol-1, with an average of 206.799 kJ mol-1. The peak of activation energy distribution curve was located at 205.929 kJ mol-1, consistent with the thermogravimetric results. The Flynn-Wall-Ozawa and distributed activation energy model methods were more reliable for describing the polyurethane foam pyrolysis process.


Assuntos
Calefação , Pirólise , Cinética , Poliuretanos , Termogravimetria
20.
Sci Total Environ ; 699: 134403, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31678873

RESUMO

One of the key challenges noted in the sustainable development goals for good health and wellbeing (SDGs 3) is both ambient and household air pollution. Household solid fuel combustion represents one of the biggest threat to human health in South Africa. This study helps to understand the impact of solid fuel burning in an indoor and ambient environment. Continuous monitoring of particulate matter (PM4) was carried out in two houses, one used coal as a primary source of energy, while the other did not. For solid fuel burning (SFB) house the winter PM4 average 24-h concentration ranges between 60.9 µg m-3 and 207.5 µg m-3 while at non-solid fuel burning (NSFB) house it ranges between 15.3 µg m-3 and 84.2 µg m-3. In both houses, the national ambient air quality standard (NAAQS) for PM2.5 (40 µg m-3) were exceeded during winter. The summer PM4 levels ranged between 17.4 µg m-3 and 36.6 µg m-3 in the solid fuel burning house and between 14.2 µg m-3 and 39.9 µg m-3 at the non-solid fuel-burning house. During mornings and evenings, indoor concentrations were higher than the outdoor; these periods coincide with the fuel-burning pattern in this community. In the mid-afternoon, the outdoor PM levels sometimes went higher than the indoor levels, perhaps as a result of the pollution from the power plants in the neighbourhood. Using the linear regression model, there were no significant correlations between indoor/outdoor PM4 concentrations during the winter, but there were good correlations for both houses during the summer. There was an observed difference in the thermal comfort at the SFB and NSFB. The temperature at SFB went below the World Health Organisation standard in winter and above during the summer while at NSFB, the temperature was managed within the standard in both seasons.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Carvão Mineral , Exposição Ambiental/estatística & dados numéricos , Monitoramento Ambiental , Material Particulado , Poluição do Ar , Culinária , Características da Família , Calefação , Humanos , Centrais Elétricas , Estações do Ano , África do Sul , Madeira
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