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1.
Sci Rep ; 12(1): 20842, 2022 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-36460682

RESUMO

The fluid oil and gas volumes (S1) retained within the shales are one of the most important parameter of producible fluid oil and gas saturations of shales together with total organic carbon content. The S1 volumes can directly be obtained by Rock-Eval pyrolysis analysis. However, it is time consuming and not practical to obtain samples from all intervals of all wells in any shale play. S1 volumes prediction with a deep learning (DL) model have increasingly became important with the booming exploration and development of shale oil and gas resources. S1 volumes of shales are controlled by organic matter richness, type and maturity together with reservoir quality and adsorption capacity which are mainly effected by age, depth, organic content, maturity and mineralogy. A dataset consisting of 331 samples from 19 wells of various locations of the world-class organic-rich shales of the Niobrara, Eagle Ford, Barnett, Haynesville, Woodford, Vaca Muerta and Dadas has been used to determination of a DL model for S1 volumes prediction using Python 3 programing environment with Tensorflow and Keras open-source libraries. The DL model that contains 5 dense layers and, 1024, 512, 256, 128 and 128 neurons has been predicted S1 volumes of shales as high as R2 = 0.97 from the standard petroleum E&P activities. The DL model has also successfully been applied to S1 volumes prediction of the Bakken and Marcellus shales of the North America. The prediction of the S1 volumes show that the shales have lower to higher reservoir quality and, oil and gas production rate that are well-matches with former studies.


Assuntos
Aprendizado Profundo , Utensílios Domésticos , Minerais , Adsorção , Neurônios
2.
PLoS One ; 17(12): e0278046, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36454721

RESUMO

Given the increased use of air cleaners as a prevention measure in classrooms during the COVID-19 pandemic, this study aimed to investigate the effects of portable air cleaners with HEPA filters and window A/C fans on real-time (1 minute) concentrations of PM less than 2.5 microns (PM2.5) or less than 1 microns (PM1.0) in two classrooms in a non-urban elementary school in Rhode Island. For half of each school day, settings were randomized to "high" or "low" for the air cleaner and "on" or "off" for the fan. Descriptive statistics and linear mixed models were used to evaluate the impacts of each set of conditions on PM2.5 and PM1.0 concentrations. The mean half-day concentrations ranged from 3.4-4.1 µg/m3 for PM2.5 and 3.4-3.9 µg/m3 for PM1.0. On average, use of the fan when the air cleaner was on the low setting decreased PM2.5 by 0.53 µg/m3 [95% CI: -0.64, -0.42] and use of the filter on high (compared to low) when the fan was off decreased PM2.5 by 0.10 µg/m3 [95% CI: -0.20, 0.005]. For PM1.0, use of the fan when the air cleaner was on low decreased concentrations by 0.18 µg/m3 [95% CI: -0.36, -0.01] and use of the filter on high (compared to low) when the fan was off decreased concentrations by 0.38 µg/m3 [95% CI: -0.55, -0.21]. In general, simultaneous use of the fan and filter on high did not result in additional decreases in PM concentrations compared to the simple addition of each appliance's individual effect estimates. Our study suggests that concurrent or separate use of an A/C fan and air cleaner in non-urban classrooms with low background PM may reduce classroom PM concentrations.


Assuntos
COVID-19 , Utensílios Domésticos , Humanos , Material Particulado , Pandemias , COVID-19/epidemiologia , COVID-19/prevenção & controle , Instituições Acadêmicas
3.
Sensors (Basel) ; 22(23)2022 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-36501908

RESUMO

Surface reflectance is an essential product from remote sensing Earth observations critical for a wide variety of applications, including consistent land cover mapping and change, and estimation of vegetation attributes. From 2000 to 2017 the Earth Observing-1 Hyperion instrument acquired the first satellite based hyperspectral image archive from space resulting in over 83,138 publicly available images. Hyperion imagery however requires significant preprocessing to derive surface reflectance. SUREHYP is a Python package designed to process batches of Hyperion images, bringing together a number of published algorithms and methods to correct at sensor radiance and derive surface reflectance. In this paper, we present the SUREHYP workflow and demonstrate its application on Hyperion imagery. Results indicate SUREHYP produces flat terrain surface reflectance results comparable to commercially available software, with reflectance values for the whole spectral range almost entirely within 10% of the software's over a reference target, yet it is publicly available and open source, allowing the exploitation of this valuable hyperspectral archive on a global scale.


Assuntos
Utensílios Domésticos , Algoritmos , Planeta Terra , Imagens, Psicoterapia , Software
4.
Sensors (Basel) ; 22(23)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36501994

RESUMO

Digital twins technology (DTT) is an application framework with breakthrough rules. With the deep integration of the virtual information world and physical space, it becomes the basis for realizing intelligent machining production lines, which is of great significance to intelligent processing in industrial manufacturing. This review aims to study the application of DTT and the Metaverse in fluid machinery in the past 5 years by summarizing the application status of pumps and fans in fluid machinery from the perspective of DTT and the Metaverse through the collection, classification, and summary of relevant literature in the past 5 years. The research found that in addition to relatively mature applications in intelligent manufacturing, DTT and Metaverse technologies play a critical role in the development of new pump products and technologies and are widely used in numerical simulation and fault detection in fluid machinery for various pumps and other fields. Among fan-type fluid machinery, twin fans can comprehensively use technologies, such as perception, calculation, modeling, and deep learning, to provide efficient smart solutions for fan operation detection, power generation visualization, production monitoring, and operation monitoring. Still, there are some limitations. For example, real-time and accuracy cannot fully meet the requirements in the mechanical environment with high-precision requirements. However, there are also some solutions that have achieved good results. For instance, it is possible to achieve significant noise reduction and better aerodynamic performance of the axial fan by improving the sawtooth parameters of the fan and rearranging the sawtooth area. However, there are few application cases of the Metaverse in fluid machinery. The cases are limited to operating real equipment from a virtual environment and require the combination of virtual reality and DTT. The application effect still needs further verification.


Assuntos
Utensílios Domésticos , Tecnologia , Comércio , Tecnologia Digital , Indústrias
5.
Sensors (Basel) ; 22(23)2022 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-36501830

RESUMO

In the blockchain system, mining pools are popular for miners to work collectively and obtain more revenue. Nowadays, there are consensus attacks that threaten the efficiency and security of mining pools. As a new type of consensus attack, the Fork After Withholding (FAW) attack can cause huge economic losses to mining pools. Currently, there are a few evaluation tools for FAW attacks, but it is still difficult to evaluate the FAW attack protection capability of target mining pools. To address the above problem, this paper proposes a novel evaluation framework for FAW attack protection of the target mining pools in blockchain systems. In this framework, we establish the revenue model for mining pools, including honest consensus revenue, block withholding revenue, successful fork revenue, and consensus cost. We also establish the revenue functions of target mining pools and other mining pools, respectively. In particular, we propose an efficient computing power allocation optimization algorithm (CPAOA) for FAW attacks against multiple target mining pools. We propose a model-solving algorithm based on improved Aquila optimization by improving the selection mechanism in different optimization stages, which can increase the convergence speed of the model solution and help find the optimal solution in computing power allocation. Furthermore, to greatly reduce the possibility of falling into local optimal solutions, we propose a solution update mechanism that combines the idea of scout bees in an artificial bee colony optimization algorithm and the constraint of allocating computing power. The experimental results show that the framework can effectively evaluate the revenue of various mining pools. CPAOA can quickly and accurately allocate the computing power of FAW attacks according to the computing power of the target mining pool. Thus, the proposed evaluation framework can effectively help evaluate the FAW attack protection capability of multiple target mining pools and ensure the security of the blockchain system.


Assuntos
Blockchain , Utensílios Domésticos , Algoritmos , Consenso
6.
Sci Rep ; 12(1): 19025, 2022 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-36347880

RESUMO

Detached off-grids, subject to the generated renewable energy (RE), need to balance and compensate the unstable power supply dependent on local source potential. Power quality (PQ) is a set of EU standards that state acceptable deviations in the parameters of electrical power systems to guarantee their operability without dropout. Optimization of the estimated PQ parameters in a day-horizon is essential in the operational planning of autonomous smart grids, which accommodate the norms for the specific equipment and user demands to avoid malfunctions. PQ data for all system states are not available for dozens of connected / switched on household appliances, defined by their binary load series only, as the number of combinations grows exponentially. The load characteristics and eventual RE contingent supply can result in system instability and unacceptable PQ events. Models, evolved by Artificial Intelligence (AI) methods using self-optimization algorithms, can estimate unknown cases and states in autonomous systems contingent on self-supply of RE power related to chaotic and intermitted local weather sources. A new multilevel extension procedure designed to incrementally improve the applicability and adaptability to training data. The initial AI model starts with binary load series only, which are insufficient to represent complex data patterns. The input vector is progressively extended with correlated PQ parameters at the next estimation level to better represent the active demand of the power consumer. Historical data sets comprise training samples for all PQ parameters, but only the load sequences of the switch-on appliances are available in the next estimation states. The most valuable PQ parameters are selected and estimated in the previous algorithm stages to be used as supplementary series in the next more precise computing. More complex models, using the previous PQ-data approximates, are formed at the secondary processing levels to estimate the target PQ-output in better quality. The new added input parameters allow us to evolve a more convenient model form. The proposed multilevel refinement algorithm can be generally applied in modelling of unknown sequence states of dynamical systems, initially described by binary series or other insufficient limited-data variables, which are inadequate in a problem representation. Most AI computing techniques can adapt this strategy to improve their adaptive learning and model performance.


Assuntos
Inteligência Artificial , Utensílios Domésticos , Algoritmos , Energia Renovável , Sistemas Computacionais
7.
Sensors (Basel) ; 22(19)2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-36236425

RESUMO

Indoor air quality (IAQ) in houses is often deteriorated by chemical substances emitted from heating, building materials, or other household goods. Since it is difficult for occupants to recognize air pollution, they rarely understand the actual conditions of the IAQ. An investigation into the actual condition of IAQ in houses was therefore conducted in this study. Carbon dioxide (CO2) concentrations in 24 occupied houses was measured, and the results from our analysis showed that the use of combustion heaters increased the concentration of CO2 and led to indoor air pollution. Results indicate that as outdoor temperature decreased, the frequency of ventilation decreased simultaneously, and CO2 concentration increased. Results of the questionnaire survey revealed that the actual IAQ in each house did not match the level of awareness its occupants had regarding ventilation. Along with this difficulty in perceiving air pollution, the lack of knowledge about ventilation systems and the effects of combustion heating may be additional barriers to IAQ awareness.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Utensílios Domésticos , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Dióxido de Carbono/análise , Monitoramento Ambiental/métodos , Inquéritos e Questionários , Ventilação
8.
Environ Sci Technol ; 56(22): 15347-15355, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36288504

RESUMO

As the largest emission source in the Pan-Third Pole region, residential solid fuel combustion gains increasing public concern regarding air pollution-associated health impacts. This study firstly developed emission inventories by combining energy statistics, fuel-mix survey, and detailed emission factors considering different fuel types, stove types, and altitudes, and we achieved full regional coverage and increased spatial resolution from 9 × 9 km to 1 km × 1 km. Total CO2, CO, PM2.5, SO2, and NOx emissions (coefficient of variation) were estimated to be 823 Mt (24%), 53 Mt (28%), 4525 kt (48%), 1388 kt (55%), and 1275 kt (46%) in 2020. India, Pakistan, and Bangladesh combined contributed 73, 57, 65, 67, and 69% of total CO2, CO, PM2.5, SO2, and NOx emissions, respectively, due to the large population. The Qinghai-Tibet Plateau had the second-highest emission intensity, mainly due to the high fuel consumption per capita. Unlike the emissions of the Pan-Third Pole in existing Asian inventories, dung cake combustion dominated total PM2.5, SO2, and NOx emissions rather than firewood combustion with proportions of 54, 70, and 67%, respectively. The effect of altitude on combustion efficiencies increased PM2.5 emissions by about 21% from the region. The method and results can provide technical guidance for emission inventory refinement in the Pan-Third Pole and other regions.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Utensílios Domésticos , Poluentes Atmosféricos/análise , Material Particulado/análise , Dióxido de Carbono , Poluição do Ar/análise
9.
Sci Rep ; 12(1): 17226, 2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36241722

RESUMO

This study aims to assess the social acceptance of using solar energy based cooking appliances in Gaza Strip. A study sample that consists of 2400 employees from three local universities in Gaza strip is targeted in study. Meanwhile, 347 participations have participated in the study. This gives the conclusions of the study a margin of error of 5% and a confidence level of 95%. Different attributes are used to measure the social acceptance of the respondents of solar energy cooking systems including knowledge of using solar cooking appliances, financial situation, educational level, age, career and gender. According to the results, 94.55% of the participants believe that the best usage of solar energy is for lighting. Meanwhile, only 37.7% of the participants have supported the usage of solar energy for cooking. It is also concluded that there are no statistical significant differences in using solar energy for cooking associated with gender and job status. Meanwhile, it is found that there is statistical significance of using solar energy for cooking associated with education and age. This shows a clear behavioral barrier for the usage of solar energy cooking systems in Gaza Strip. According to this research it is concluded that end-users with middle income put quality of life first before the technology cost (affordable costs). This conclusion is regardless the educational level of the respondents. Moreover, it is found that Funding schemes and loans are key issues in spreading the e-cooking. Finally it is concluded that noticed support of using solar energy in Gaza according to this research is directly associated with energy poverty status in Gaza. Meanwhile, the idea of using green alternative energy is very acceptable in Gaza but there is a clear lack of awareness of technologies aspects and characteristics.


Assuntos
Utensílios Domésticos , Qualidade de Vida , Culinária , Humanos , Oriente Médio , Status Social
10.
Artigo em Inglês | MEDLINE | ID: mdl-36231220

RESUMO

INTRODUCTION: Exposure assessment of intermediate frequency (IF) electromagnetic fields (EMFs) is difficult and epidemiological studies are limited. In the present study, we aimed to estimate the exposure of pregnant women to IF-EMFs generated by induction cookers in the household using a questionnaire and discussed its applicability to epidemiological studies. METHOD: Two main home-visit surveys were conducted: a Phase 1 survey to develop an estimation model and a Phase 2 survey to validate the model. The estimation model included the following variables: wattage, cookware diameter, and distance from the hob center (center of the stove). Four models were constructed to determine the importance of each variable and the general applicability for epidemiological studies. In addition, estimated exposure values were calculated based on the Phase 2 survey questionnaire responses and compared with the actual measured values using the Spearman rank correlation coefficient. RESULT: The average value of the magnetic field measured in the Phase 1 survey was 0.23 µT (variance: 0.13) at a horizontal distance of 30 cm at the height of the cooking table. The highest validity model was inputted distance from the hob center to the body surface that is variable (correlation coefficient = 0.54, 95% confidence interval: 0.22-0.75). No clear differences were identified in the correlation coefficients for each model (z-value: 0.09-0.18, p-value: 0.86-0.93). DISCUSSION AND CONCLUSIONS: No differences were found in the validity of the four models. This could be due to the biased wattage of the validation population, and for versatility it would be preferable to use three variables (distance, wattage, and estimation using the diameter of the cookware) whenever possible. To our knowledge, this is the first systematic measurement of magnetic fields generated by more than 70 induction cookers in a real household environment. This study will contribute to finding dose-response relationships in epidemiological studies of intermediate-frequency exposure without the use of instrumentation. One of the limitations of this study is it estimates instantaneous exposure in place during cooking only.


Assuntos
Exposição Ambiental , Utensílios Domésticos , Campos Eletromagnéticos/efeitos adversos , Estudos Epidemiológicos , Feminino , Humanos , Campos Magnéticos , Gravidez
11.
Waste Manag ; 153: 156-166, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36096043

RESUMO

China has the highest level of plastic production and consumption in the world. The plastic waste ban has resulted in a lack of raw materials for plastic reprocessing, while household appliance-related plastic (HAP), as a high-value and high-quality plastic waste source, receives great attention to fill such a gap. As HAP is scattered and has been rapidly increasing, a better understanding of the spatial-temporal patterns of HAP waste is critical. For the first time, this study quantifies the stocks and flows of plastics contained in five categories of household appliances (refrigerator, washing machine, air conditioner, TV, and computer) in China over 1978-2016 and maps their province-specific distribution through a dynamic stock-driven material flow analysis model. We find that (i) the HAP stocks are growing rapidly to reach around 25.4 million tonnes (MT) in 2016 and the HAP waste generated in 2016 is over 2 MT while the dismantling capacity is failing to catch up; (ii) the HAP waste in southeastern provinces is notably more than in northwestern provinces by approximately 11 times; (iii) washing machines (37%) and refrigerators (24%) are the major types of household appliances that contribute most to HAP waste generation; (iv) PP (38%) and PS (34%) are the major plastic types in HAP waste. These findings can provide quantitative references for the government to arrange waste management facilities, improve recycling capacities of dismantling companies, and promote coordinated efforts from multiple stakeholders to achieve efficient waste management of HAP.


Assuntos
Utensílios Domésticos , Gerenciamento de Resíduos , China , Plásticos , Reciclagem/métodos , Gerenciamento de Resíduos/métodos
12.
Sci Rep ; 12(1): 16291, 2022 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-36175432

RESUMO

An important structuring feature of a soccer match is the in-game status, whether a match is interrupted or in play. This is necessary to calculate performance indicators relative to the effective playing time or to find standard situations, ball actions, and other tactical structures in spatiotemporal data. Our study explores the extent to which the in-game status can be determined using time-continuous player positions. Therefore, to determine the in-game status we tested four established machine learning methods: logistic regression, decision trees, random forests, and AdaBoost. The models were trained and evaluated using spatiotemporal data and manually annotated in-game status of 102 matches in the German Bundesliga. Results show up to 92% accuracy in predicting the in-game status in previously unknown matches on frame level. The best performing method, AdaBoost, shows 81% precision for detecting stoppages (longer than 2 s). The absolute time shift error at the start was ≤ 2 s for 77% and 81% at the end for all correctly predicted stoppages. The mean error of the in-game total distance covered per player per match using the AdaBoost in-game status prediction was - 102 ± 273 m, which is 1.3% of the mean value of this performance indicator (7939 m). Conclusively, the prediction quality of our model is high enough to provide merit for performance diagnostics when teams have access to player positions (e.g., from GPS/LPM systems) but no human-annotated in-game status and/or ball position data, such as in amateur or youth soccer.


Assuntos
Utensílios Domésticos , Futebol , Adolescente , Atletas , Humanos , Aprendizado de Máquina , Fases de Leitura
14.
J Air Waste Manag Assoc ; 72(7): 762-776, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775653

RESUMO

The use of wood as a fuel for home heating is a concern from an environmental health and safety perspective as biomass combustion appliances emit high concentrations of particulate matter. Wood burning significantly contributes to wintertime particulate matter concentrations in many states in the northern United States. Of particular concern are outdoor wood-fired hydronic heaters. These devices are concerning as they tend to have very large combustion chambers and typical use patterns can result in long periods of low output, which result in an increased particulate matter emission rate relative to high heat output operating conditions. In this study, the performance of two hydronic heaters operating under different combustion conditions, including four different heat output categories approximately corresponding to categories I-IV denoted in Environmental Protection Agency Method 28 Outdoor Wood-fired Hydronic Heaters, and during start-up and reloading events were investigated. Measurements of flue gas particulate number concentration and size for particles with aerodynamic diameters between 0.006 and 10 µm were made using a dilution sampling system. The measured particle number concentration in the flue gas was between 0.71 and 420 million particles per cubic centimeter and was dependent on fuel loading and heat output. For each hydronic heater tested, the highest average particle concentration was found at the beginning of each test during the cold-start condition. Additionally, the majority of the particles had aerodynamic diameters less than 0.100 µm (particles of this size made up between 64% and 97% of all particles) and less than 1% of all particles had aerodynamic diameters greater than 1 µm for all phases. For particles in the accumulation mode, between 0.100 and 1 µm, the mean particle diameter was dependent on fuel loading and heat output.Implications: In this work, we provide information on the particle number concentration and particle size of emissions from outdoor cord- wood-fired hydronic heaters. Wood-fired hydronic heater data is sparsely available compared to wood stove data. Thus, additional data from this source help to inform the work of modelers and policy makers interested in hydronic heaters. The test method used in this work is also novel, as it is more inclusive of real-world use cases than the current certification method. Our data helps to validate the test method and allows for comparisons between real-world use case scenarios, and idealized test cases.


Assuntos
Utensílios Domésticos , Calefação , Produtos Domésticos , Material Particulado , Madeira
15.
J Air Waste Manag Assoc ; 72(7): 619-628, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775654

RESUMO

Air pollution from residential wood heating poses a significant public health risk and is a primary cause of PM nonattainment in some areas of the United States. Those emissions also play a role in regional haze and climate change. While regulatory programs have focused on emissions reductions from large facilities, the residential heating sector has received limited attention. The failure to develop effective programs to address this emission source hampers the ability of state and local air quality programs to meet clean air goals. An updated New Source Performance Standard (NSPS) for Residential Wood Heaters was promulgated in 2015, which includes more stringent emissions standards for wood stoves and broadens its scope to regulate additional types of wood heating appliances. However, weaknesses in the test methods and programs used to certify compliance with the NSPS limits hamper the efficacy of those requirements. Current emissions certification tests measure stove performance under defined laboratory conditions that (1) do not adequately reflect operation and performance of appliances in homes, (2) are not sufficiently repeatable to allow for comparison of emissions of different appliances, and (3) allow manufacturers leeway to modify critical test fueling and operating parameters which can significantly impact performance outcomes. These foundational regulatory issues present substantial challenges to promoting the cleanest and most efficient wood heating systems. This paper provides an overview of the air quality and public health impacts of residential wood heating and discusses the weaknesses in the current emission certification approaches and work by the Northeast States for Coordinated Air Use Management (NESCAUM) and the New York State Energy Research and Development Authority to develop improved testing methods. Other articles in this issue discuss the development and testing of those methods in detail.Implications: Air pollution from residential wood heating poses a significant public health risk and is a primary cause of PM nonattainment in some areas of the United States. Those emissions also play a role in regional haze and climate change. While regulatory programs have focused on emissions reductions from large facilities, the residential heating sector has received limited attention. The failure to develop effective programs to address this emission source hampers the ability of state and local air quality programs to meet clean air goals. This paper provides an overview of the issue.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Utensílios Domésticos , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Calefação , Estados Unidos , Madeira/química
16.
J Air Waste Manag Assoc ; 72(7): 679-699, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775656

RESUMO

Many believe that certification testing of residential wood heat appliances should provide data indicative of installed performance. Operationally, test methods typically only assess steady-state emissions and fail to include other typical conditions for batch appliances such as start-up. From a fueling perspective, protocols should ensure a consistent approach reflecting common use practices. Ensuring representative conditions and accurate quantification of emissions requires assessing the impact of different start-up conditions and whether or not start-up conditions affect appliance operation during start-up and beyond. This study evaluated the impact of modifying fuel piece sizes and configurations using a "smart" wood-fired hydronic heater (WHH) cordwood appliance. The appliance represents technologies using software and oxygen sensors to improve performance. Since the study used a "smart" appliance, the results likely reflect the least amount of variability found in a WHH cordwood appliance. The analysis consisted of a series of tests that involved changing one fuel variable per series, including: (1) kindling fuel arrangement in the firebox; (2) fuel piece size; and (3) the amount of kindling and starter fuel used. A goal of the study was to determine how each variable affects emissions performance during start-up and the following steady state load. Testing used a dual-stage combustion cordwood WHH equipped with external thermal storage. Particulate matter (PM), carbon monoxide (CO), and delivered heating efficiency were measured, and visible emissions from the stack and secondary combustion chamber were observed. Replicate tests were conducted for each protocol series to evaluate WHH performance reproducibility. These tests found that for a low-mass staged combustion WHH with external thermal storage, the use of different fueling protocols can substantially affect PM and CO emissions.Implications: As test methods move to incorporate measurements beyond steady-state emissions, fueling protocols must be assessed to determine (1) if they reflect typical field procedures and (2) the impact of start-up procedures on the complete test run. This paper assessed how changing start-up conditions affected run variability and PM emission impacts.


Assuntos
Poluentes Atmosféricos , Utensílios Domésticos , Poluentes Atmosféricos/análise , Material Particulado/análise , Reprodutibilidade dos Testes , Madeira/química
17.
J Air Waste Manag Assoc ; 72(7): 720-737, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775657

RESUMO

In the current work, we provide measurements of size-resolved particle number concentration (PNC), particle mass concentration (PMC), lung-deposited surface area (LDSA), and black carbon (BC) concentration for three biomass fired hydronic heaters during operation in four different combustion conditions. The appliances include one woodchip-fueled hydronic heater and two outdoor cordwood-fueled hydronic heaters. The operating conditions included startup, low output, high output, and burnout. Measurements were made using a custom dilution sampling system and a suite of commercially available, time-resolved, ambient aerosol measurement instrumentation. The PNC, as measured using an Dekati Electrical Low Pressure Impactor+ (ELPI), had operating condition mean values ranging between 4.1 and 52 million particles per cubic centimeter (#/cm3). The highest reported PNC occurred during the startup condition in all cases. Calculating the particle size distribution measured across each operating phase for the same instrument gave geometric mean diameters (dg) in the range of 0.080-0.256 µm. The largest dg per appliance was nearly always attributable to the startup condition (for hydronic heater 1, startup dg ranked second).We did not observe the same trends when we transformed the ELPI PNC to PMC and particle surface area concentration estimates across operating conditions, suggesting PNC and dg are highly variable. Furthermore, simultaneous measurements of PNC, PMC, and PSAC using instrumentation with different working principles gave varying results, potentially suggesting that particles of different composition and morphology are produced under different combustion conditions.Implications: In this work we compare the results from testing of 3 biomass fired hydronic heaters including one chip-fired appliance and two cordwood-fired appliances. The emissions from these appliances were made across four operating conditions and using three different non-regulatory emissions metrics. This work: describes the difference between chip and cordwood fired units and the effect of operating condition on emissions across the three emissions metrics.


Assuntos
Poluentes Atmosféricos , Utensílios Domésticos , Poluentes Atmosféricos/análise , Carvão Mineral , Poeira , Madeira/química
18.
J Air Waste Manag Assoc ; 72(7): 647-661, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775658

RESUMO

Homeowners burn wood of a wide range of species and moisture content (MC) in residential cordwood and pellet stoves. An effective emission certification test protocol must account for and accurately measure the impact of those variables in order to ensure a reasonable correlation between laboratory results and in-use emissions and to promote the design and manufacture of cleaner burning appliances. This study explored the effect of wood species and MC on emissions and efficiency in four cordwood and four pellet stoves. PM emissions were consistently lower with pellets manufactured from softwood than for hardwood species and were highly correlated with ash content. Higher MC oak fuel substantially increased PM emissions in a non-catalytic cordwood stove; however, a hybrid cordwood stove was able to meet federal emissions limits even with the higher MC fuel. The results of this study, in combination with previous research, suggest that certification tests that use softwood fuel likely report lower emissions than tests that use hardwood. Requiring hardwood and higher MC cordwood fuel in certification tests would enable the assessment of an appliance's ability to operate well even when fuel conditions are not optimized.Implications: The emission testing results reported in this paper call into question the adequacy of the fuel moisture content and fuel species specifications in testing protocols approved for certifying compliance with EPA's New Source Performance Standards for cordwood and pellet stoves. We recommend changes in those specifications, including the prohibition of testing with Douglas fir and other low ash softwood species, requiring the use of cordwood test fuel with a higher moisture content, and requiring pellet stoves to be tested using hardwood pellets. Adoption of these measures would increase the replicability of tests. allow for the identification of stoves that are unlikely to perform well in the field when fuel conditions are not ideal, and, ultimately, result in the design of cleaner burning stoves.


Assuntos
Utensílios Domésticos , Madeira , Produtos Domésticos
19.
J Air Waste Manag Assoc ; 72(7): 629-646, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775660

RESUMO

The US Environmental Protection Agency's (EPA's) New Source Performance Standards (NSPS) for Residential Wood Heaters (RWH) require certification emission testing of prototype appliances. In 2015, EPA revised those standards to further reduce particulate matter emissions from this critical source. However, to achieve that goal, lower emissions measured in certification tests must reflect lower emissions when the appliance is operated in homes. Woodstove certification tests have used either the Federal Reference Method (FRM), a crib wood method, or a cordwood testing method developed by ASTM International that was designated as a broadly applicable Alternative Test Method (ATM) by the EPA until December 2021, when that status was revoked. There is broad agreement that the FRM and ASTM procedures do not simulate typical fueling and operating of wood stoves in the field, raising questions about the efficacy of the current program. Effective emission reduction efforts require robust, accurate, and reproducible test methods. With input from a range of stakeholders, the Northeast States for Coordinated Air Use Management (NESCAUM) developed the Integrated Duty Cycle Test Method for Certification of Wood-Fired Stoves Using Cordwood (IDC), a cordwood testing protocol designed to improve the efficacy of residential wood heater certification testing. That method was approved by EPA as a broadly applicable ATM in 2021. IDC test runs assess appliance performance under a range of operating and fueling conditions representative of typical consumer use patterns. Unlike previous test methods, the IDC protocol requires three replicate runs to assess appliance performance variability. Including variable fueling and operating conditions, along with the requirement for replicates runs, will increase the effectiveness of certification testing and promote the development of improved wood stove technology. This paper reports on experiments conducted to develop and test the IDC method.Implications: Residential wood heating is one of the largest sources of primary particulate matter pollution nationwide. EPA's New Source Performance Standards (NSPS) establish emission limits for this source category and require certification testing of prototype wood appliances to demonstrate compliance with those limits. However, the operating and fueling requirements in NSPS compliance testing protocols do not represent typical conditions in the field. We developed a new testing approach, the Integrated-Duty Cycle (IDC) Test Method, to address the shortcomings of current certification test approaches. The IDC procedure for cordwood stoves, which was approved by EPA as a broadly applicable alternative test method in 2021, assesses appliance operations over various operating and fueling conditions representing typical consumer use patterns in an integrated run and requires three replicate runs to enable the assessment of variability in stove performance. Stoves certified with this method will be equipped to meet the NSPS limits consistently in field operation.


Assuntos
Poluentes Atmosféricos , Utensílios Domésticos , Poluentes Atmosféricos/análise , Calefação/métodos , Produtos Domésticos , Material Particulado/análise
20.
J Air Waste Manag Assoc ; 72(7): 662-678, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35775661

RESUMO

The U.S. Environmental Protection Agency (US EPA) requires residential wood heaters (RWHs) to meet particulate matter (PM) emission limits in order to lower ambient concentrations and reduce public exposure. The current US EPA dilution tunnel PM measurement methods for RWHs were developed several decades ago and use manual filter samples to generate a single PM value for tests that can last more than 12 hours for stoves and 30 hours for central heating appliances. This approach results in averaging periods of high and low emissions together and provides limited data on emissions over the entire burn profile. Over the last decade, the U.S. ambient fine particulate monitoring network has transitioned to the routine use of online automated methods. However, stationary source measurement methods have not made this transition. There are no substantial technical issues in implementing real-time automated methods to measure PM for RWH emission certification purposes. The Thermo Scientific Tapered Element Oscillating Microbalance (TEOM™) has been widely used for ambient PM measurements. It is a true inertial mass measurement with high time resolution and sensitivity. This work compares measurements obtained using a Thermo 1400 or 1405 TEOM with ASTM E2515 manual filter samples, the current US EPA Federal Reference Method, for 172 test runs across a wide range of stoves and PM loading conditions. The TEOM measurements used the same filter media, similar filter face velocities, and filter temperatures as manual methods. PM measurements were well correlated (R2 > 0.9), with TEOM values typically lower by 5% to 10%. TEOM data capture was high, with filter changes resulting in ~5 minutes of lost data, usually once or twice during a multi-hour test. We discuss differences between the two methods, such as post-sampling equilibration and measurement of PM on sample train surfaces (probe "catch"). We also provide examples of substantial non-water semi-volatile mass loss during sampling.Implications: Measurement methods for continuous PM and our understanding of their performance has dramatically improved over the last thirty years. Highly time-resolved measurements of PM from residential wood heating appliances in an appliance certification testing context provide additional insight into both appliance performance and the suitability of the test method to assess that performance. This continuous measurement approach offers new opportunities to replace traditional US regulatory PM sampling integrated manual source methods like ASTM E2515 or EPA Method 5G testing. For measurement of combustion products that can have a wide range of physical and chemical characteristics, the TEOM's actual mass measurement principle has advantages over the sensitivity of surrogate methods to different aerosols for use in a regulatory program. Although the TEOM is commonly used to measure ambient PM, it can readily be configured to meet the needs of continuous emission testing.


Assuntos
Utensílios Domésticos , Material Particulado , Aerossóis/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Madeira/química
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