Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well...Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma treatment.As a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V vs.reversible hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported electrocatalysts.Impressively,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling stability.First-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics rates.This work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs.展开更多
Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effective...Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.展开更多
To solve the problem that utilizing an air rower lowers indoor air quality due to the dust stirred up in the course of rowing, an air rower is designed to have the extra function of air purifying. The designed rower i...To solve the problem that utilizing an air rower lowers indoor air quality due to the dust stirred up in the course of rowing, an air rower is designed to have the extra function of air purifying. The designed rower is composed of six parts, which are the frame, air generator, transmission part, air purifying filter cartridge, performance monitor, and electric motor. To fulfill the task, the filter cartridge is vertically arranged to lead the air to enter from the lower part and vent out of the upper part to filter and purify the air before it enters the generator so as that the indoor air is well circulated to improve the air purification effect when the rower is utilizing. The modular detachable design allows the air filter and electric motor to be installed and disassembled to adapt to different air purification needs. The designed rower has the benefit of lower purchasing cost and energy saving that may motivate exercising, bringing more fun and the sense of accomplishment.展开更多
Air cannon is a kind of de-clogging device which produces impulse force by instantly releasing the compressed air deposited in a pressure vessel. Air cannons are widely used in the transport pipes of warehouses, docks...Air cannon is a kind of de-clogging device which produces impulse force by instantly releasing the compressed air deposited in a pressure vessel. Air cannons are widely used in the transport pipes of warehouses, docks, furnaces and coal mines. In this paper, the theoretical analysis with isentropic flow hypothesis is firstly conducted on a simplified mode/ to deduce the theo- retical maximum of impulse force. And numerical study is carried out to predict the steady and unsteady impulse forces via simulating the whole exhausting process of the air cannon. The results demonstrate that the impulse force can be improved via increasing the piston sleeve inlet length and increasing the nozzle diameter. Laval nozzle can also increase the impulse force of the air without increasing the air mass flow. The optimization of the air cannon is then conducted on the basis of the theoretical and numerical analyses. Experimental measurements indicate that the computations well simulate the working process of the air cannon and the impulse force of the optimized design is 50% higher than the original model. For the cases with working pressure of 0.8 MPa, the optimized design is 60% higher than the original one.展开更多
[Objective] The study aimed to provide supports for developing chilling and freezing injury monitoring and disaster damage assessment of longan(Dimocarpus Longan Lour.).[Method] Based on field observation data,the rel...[Objective] The study aimed to provide supports for developing chilling and freezing injury monitoring and disaster damage assessment of longan(Dimocarpus Longan Lour.).[Method] Based on field observation data,the relationships between longan canopy temperature and air temperature under different weather types(sunny,cloudy to sunny,cloudy,rainy,radiation chilling injury and advection chilling injury)in 2007-2008 winter were analyzed.[Result] Diurnal variations of longan canopy temperature under sunny and radiation chilling injury weather conditions were most dramatic,followed with those under cloudy to sunny condition,while variations under cloudy,rainy and advection chilling injury conditions were mild.Diurnal variations of orchard air temperature were also closely related to weather types.By using linear and curvilinear regression methods,the relationship models between longan canopy temperature and observation station air temperature were established.The models for cloudy,rainy and advection chilling injury had better effects than those for sunny,cloudy to sunny and radiation chilling injury;the models for night were better than those for daytime and the whole day.[Conclusion] To some extent,applying the relationship models between longan canopy temperature and observation station air temperature could make up the shortcoming of meteorological data which were higher than the real values.展开更多
Each year there will be an estimated 2.1 million new lung cancer cases and 1.8 million lung cancer deaths worldwide.Tobacco smoke is the No.1 risk factors of lung cancer,accounting for>85%lung cancer deaths.Air pol...Each year there will be an estimated 2.1 million new lung cancer cases and 1.8 million lung cancer deaths worldwide.Tobacco smoke is the No.1 risk factors of lung cancer,accounting for>85%lung cancer deaths.Air pollution,or haze,comprises ambient air pollution and household air pollution,which are reported to cause 252,000 and 304,000 lung cancer deaths each year,respectively.Tobacco smoke and haze(hereafter,smohaze)contain fine particles originated from insufficient combustion of biomass or coal,have quite similar carcinogens,and cause similar diseases.Smohaze exert hazardous effects on exposed populations,including induction of a large amount of mutations in the genome,alternative splicing of mRNAs,abnormalities in epigenomics,initiation of tumor-promoting chronic inflammation,and facilitating immune escape of transformed cells.Tackling smohaze and development of multi-targets-based preventive and therapeutic approaches targeting smohaze-induced carcinogenesis are the key to conquer lung cancer in the future.展开更多
Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow. NIOSH tested it due to its unique design that differed from canopies that provided uniform airflow. Based upon NIOSH ...Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow. NIOSH tested it due to its unique design that differed from canopies that provided uniform airflow. Based upon NIOSH recommendations from the earlier testing, a 3rd generation roof bolter CAC has been developed by J.H. Fletcher & Co. The changes to this CAC involve design modifications to the plenum outlets, using a single row of outlets on the perimeter and a different material for the plenum. This laboratory testing was a continuation of the original perimeter slotted CAC design. Using gravimetric and instantaneous sampling of respirable dust concentrations underneath and outside of the CAC. the laboratory testing was completed using three different blower fans that delivered differing airflows. The maximum plenum airflow velocities ranged from 2.34 to 3.64 m/s (460-716 fpm). Results showed plenum respirable dust concentrations ranging from 34.6% to 49.3% lower than respirable dust concentrations outside the plenum protection zone, thus showing an improvement in protection for the roof bolter operators.展开更多
Atmospheric InfraRed Sounder (AIRS) measurements are a valuable supplement to current observational data,especially over the oceans where conventional data are sparse.In this study,two types of AIRS-retrieved temper...Atmospheric InfraRed Sounder (AIRS) measurements are a valuable supplement to current observational data,especially over the oceans where conventional data are sparse.In this study,two types of AIRS-retrieved temperature and moisture profiles,the AIRS Science Team product (SciSup) and the single field-of-view (SFOV) research product,were evaluated with European Centre for Medium-Range Weather Forecasts (ECMWF) analysis data over the Atlantic Ocean during Hurricane Ike (2008) and Hurricane Irene (2011).The evaluation results showed that both types of AIRS profiles agreed well with the ECMWF analysis,especially between 200 hPa and 700 hPa.The average standard deviation of both temperature profiles was approximately 1 K under 200 hPa,where the mean AIRS temperature profile from the AIRS SciSup retrievals was slightly colder than that from the AIRS SFOV retrievals.The mean SciSup moisture profile was slightly drier than that from the SFOV in the mid troposphere.A series of data assimilation and forecast experiments was then conducted with the Advanced Research version of the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system for hurricanes Ike and Irene.The results showed an improvement in the hurricane track due to the assimilation of AIRS clear-sky temperature profiles in the hurricane environment.In terms of total precipitable water and rainfall forecasts,the hurricane moisture environment was found to be affected by the AIRS sounding assimilation.Meanwhile,improving hurricane intensity forecasts through assimilating AIRS profiles remains a challenge for further study.展开更多
Canopy air curtain (CAC) technology has been developed by the National Institute for Occupational Safety and Health (NIOSH) for use on continuous miners and subsequently roof bolting machines in underground coal m...Canopy air curtain (CAC) technology has been developed by the National Institute for Occupational Safety and Health (NIOSH) for use on continuous miners and subsequently roof bolting machines in underground coal mines to protect operators of these machines from overexposure to respirable coal mine dust. The next logical progression is to develop a CAC for shuttle cars to protect operators from the same overexposures. NIOSH awarded a contract to Marshall University and J.H. Fletcher to develop the shuttle car CAC. NIOSH conducted laboratory testing to determine the dust control efficiency of the shuttle car CAC. Testing was conducted on two different cab configurations: a center drive similar to that on a Joy 10SC32AA cab model and an end drive similar to that on a Joy 10SC32AB cab model. Three different ventilation velocities were tested-0.61, 2.0, 4.3 rrds (120, 400, and 850 fpm). The lowest, 0.61 m/s (120 fpm), represented the ventilation velocity encountered during loading by the continuous miner, while the 4.3 m/s (850 fpm) velocity represented ventilation velocity airflow over the shuttle car while tramming against ventilation airflow. Test results showed an average of the dust control efficiencies ranging from 74 to 83% for 0.61 m/s (120 fpm), 39%-43% for 2.0 m/s (400 fpm), and 6%-16% for 4.3 m/s (850 fpm). Incorporating an airflow spoiler to the shuttle car CAC design and placing the CAC so that it is located 22.86 cm (9 in.) forward of the operator improved the dust control efficiency to 51%-55% for 4.3 m/s (850 fpm) with minimal impact on dust control efficiencies for lower ventilation velocities. These laboratory tests demonstrate that the newly developed shuttle car CAC has the potential to successfully protect shuttle car operators from coal mine respirable dust overexposures.展开更多
A 3rd generation roof bolter canopy air curtain(CAC)has been developed and constructed by J.H.Fletcher&Co.,Inc.As with the previous generation of the CAC,this design uses the principle of providing uniform airflow...A 3rd generation roof bolter canopy air curtain(CAC)has been developed and constructed by J.H.Fletcher&Co.,Inc.As with the previous generation of the CAC,this design uses the principle of providing uniform airflow across the canopy area as recommended by the National Institute for Occupational Safety and Health.The new modifications include a plenum that is constructed of a single flat aluminum plate,smaller-diameter airflow openings,and a single row of perimeter nozzles designed to prevent mine air contaminated by respirable dust from entering the CAC protection zone.Field testing was conducted on this new 3rd generation design showing reductions in coal mine respirable dust exposure for roof bolter operators.Dust control efficiencies for the CAC for the left bolter operator(intake side)ranged from approximately 26%–60%,while the efficiencies for the CAC for the right bolter operator(return side)ranged from 3%to 47%.展开更多
Epidemiological studies have suggested that inhalation exposure to indoor ambient air from coal-burning environments is causally associated with respiratory health risks.In order to explore the toxicological mechanism...Epidemiological studies have suggested that inhalation exposure to indoor ambient air from coal-burning environments is causally associated with respiratory health risks.In order to explore the toxicological mechanisms behind the adverse health effects,the hemolytic activity of PM_(10)(particulate matter with an aerodynamic diameter of 10 um or less)samples collected from homes burning coal in the recognized China"cancer village"Xuanwei were evaluated and matched against their trace elemental contents.The results demonstrated that the hemolytic activity of indoor PM_(10) in coal-burning environments ranged from 4.28%to 5.24%,with a clear positive dose-response relationship.Although low dose samples exhibited a reduced hemolytic activity,PM_(10) could have a toxic effect upon people in a coal-burning indoor environment for extended time periods.The concentrations of analyzed trace elements in PM_(10) samples ranged from 6966 to 12,958 ppm.Among the analyzed elements,Zn,Ti,Ni,Cu,Pb,Ba,Mn,Cr and V were found at higher concentrations and accounted for over 95%of the total elements.The concentrations of total analyzed elements in the PM_(10) samples revealed a significant positive correlation with PM_(10) hemolytic activity.Of the analyzed elements,Zn,Pb and Cs positively correlated with hemolysis,while Li,U and V negatively correlated with the hemolysis of human red blood cells(RBCs).Therefore,the heavy metal elements could be one of the main factors responsible for the hemolytic capacity of indoor PM_(10) in coal-burning environments.展开更多
Diabetes is a complex condition,and the causes are still not fully understood.However,a growing body of evidence suggests that exposure to air pollution could be linked to an increased risk of diabetes.Specifically,ex...Diabetes is a complex condition,and the causes are still not fully understood.However,a growing body of evidence suggests that exposure to air pollution could be linked to an increased risk of diabetes.Specifically,exposure to certain pollutants,such as particulate Matter and Ozone,has been associated with higher rates of diabetes.At the same time,air pollution has also been linked to an increased risk of thyroid cancer.While there is less evidence linking air pollution to thyroid cancer than to diabetes,it is clear that air pollution could have severe implications for thyroid health.Air pollution could increase the risk of diabetes and thyroid cancer through several mechanisms.For example,air pollution could increase inflammation in the body,which is linked to an increased risk of diabetes and thyroid cancer.Air pollution could also increase oxidative stress,which is linked to an increased risk of diabetes and thyroid cancer.Additionally,air pollution could increase the risk of diabetes and thyroid cancer by affecting the endocrine system.This review explores the link between diabetes and air pollution on thyroid cancer.We will discuss the evidence for an association between air pollution exposure and diabetes and thyroid cancer,as well as the potential implications of air pollution for thyroid health.Given the connections between diabetes,air pollution,and thyroid cancer,it is essential to take preventive measures to reduce the risk of developing the condition.展开更多
The marine sediments of the area of Verde Peninsula - Jabali Island (39°28'S/62°19%V-40°28' S/62°11'W) Holocene in age (3-2 ky), and modern beaches contain a significant amount of bioeroded ...The marine sediments of the area of Verde Peninsula - Jabali Island (39°28'S/62°19%V-40°28' S/62°11'W) Holocene in age (3-2 ky), and modern beaches contain a significant amount of bioeroded mollusc shells. Fifteen sites were analyzed, in which 20.11% of the mollusc shells (2168 valves) presented bioerosion traces, in 54 species (30 bivalves and 24 gastropods). Fourteen ichnogenera were reported: Entobia, Maeandropolydora, Iramena, Caulostrepsis, Pennatichnus, Pinaceocladichnus, Trypanites, and Gastrochaenolites (Domichnia), Gnathichnus and Radulichnus (Pascichnia), Finichnus and Centrichnus (Fixichnia), Oichnus (Praedicnia) (macrobioerosion), y Semidendrina (microbioerosion), the latter is first reported in mollusc shells in Argentina. Eleven ichnospecies were identified Finichnus peristroma, Maeandropolydora sulcans, Gnathichnus pentax, Pinaceocladichnus onubensis, Caulostrepsis taeniola, Centrichnus eccentricus, Radulichnus inopinatus, Oichnus simplex, Oichnus paraboloides, Oichnus gradatus, and Gastrochaenolites torpedo (lithic remains). The dominant ichnogenera in the Holocene deposits are Iramena, Entobia and Oichnus. The same ichnogenera are constant with different abundance in the modern beaches, and increasing representation of Pinaceocladichnus and Pennatichnus. The dominant ichnofacies in the Holocene deposits is Trypanites, revealing a benthonic marine community composed of cheilostome bryzoans, clionaid sponges, predator gastropods, regular echinoids, polychaete annelids, bivalves, thallophytas and fungi. Generally, the area was described as a sublittoral, low-energy, stable environment with high rate of oxygenation, and sandy bottoms, with rocky bottoms at Villalonga locality.展开更多
The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuatio...The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuation Analysis(DFA) during the lockdown period(March 24–April 20, 2020) and the corresponding period during the previous two years(i.e., 2018 and 2019). The analysis suggests the anticipated impact of confinement on the PMand NOconcentration in urban cities, causing low concentrations. It is observed that the original PMand NOconcentration time series is persistent but filtering the time series by fitting the autoregressive process of order 1 on the actual time series and subtracting it changes the persistence property significantly. It indicates the presence of linear correlations in the PMand NOconcentrations. Hurst exponent of the PMand NOconcentration during the lockdown period and previous two years shows that the inherent temporal characteristics of the short-term air pollutant concentrations(APCs) time series do not change even after withholding the emissions. The meteorological variations also do not change over the three time periods. The finding helps in developing the prediction models for future policy decisions to improve urban air quality across cities.展开更多
The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future...The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future applications in Zn-air battery(ZAB)and overall water splitting(OWS).Here,by combining vacancies and heterogeneous interfacial engineering,three-dimensional(3D)core-shell NiCoP/NiO heterostructures with dominated oxygen vacancies have been controllably in-situ grown on carbon cloth for using as highly efficient electrocatalysts toward hydrogen and oxygen electrochemical reactions.Theoretical calculation and electrochemical results manifest that the hybridization of NiCoP core with NiO shell produces a strong synergistic electronic coupling effect.The oxygen vacancy can enable the emergence of new electronic states within the band gap,crossing the Fermi levels of the two spin components and optimizing the local electronic structure.Besides,the hierarchical core-shell NiCoP/NiO nanoarrays also endow the catalysts with multiple exposed active sites,faster mass transfer behavior,optimized electronic strutures and improved electrochemical performance during ZAB and OWS applications.展开更多
Air pollution, both indoor and outdoor, has been found to be related to serious adverse health effects. Accurate estimation of air pollution exposure has become very important to suggest proper air pollution control p...Air pollution, both indoor and outdoor, has been found to be related to serious adverse health effects. Accurate estimation of air pollution exposure has become very important to suggest proper air pollution control policies and to further assess the effectiveness of these policies. In many instances, personal exposures have been found to be greater than concentrations measured at fixed site monitoring stations. As people spend most of their time indoors particularly during harsh weather conditions, it is necessary to consider indoor air quality in exposure assessment studies. The current paper focuses on the importance of personal exposure assessment based on spatial and temporal activity patters both indoors and outdoors.展开更多
Due to the record-breaking wildfires that occurred in Canada in 2023,unprecedented quantities of air pollutants and greenhouse gases were released into the atmosphere.The wildfires had emitted more than 1.3 Pg CO_(2)a...Due to the record-breaking wildfires that occurred in Canada in 2023,unprecedented quantities of air pollutants and greenhouse gases were released into the atmosphere.The wildfires had emitted more than 1.3 Pg CO_(2)and 0.14 Pg CO_(2)equivalent of other greenhouse gases(GHG)including CH4 and N_(2)O as of 31 August.The wildfire-related GHG emissions constituted more than doubled Canada’s planned cumulative anthropogenic emissions reductions in 10 years,which represents a significant challenge to climate mitigation efforts.The model simulations showed that the Canadian wildfires impacted not only the local air quality but also that of most areas in the northern hemisphere due to long-range transport,causing severe PM_(2.5)pollution in the northeastern United States and increasing daily mean PM_(2.5)concentration in northwestern China by up to 2μg m-3.The observed maximum daily mean PM_(2.5)concentration in New York City reached 148.3μg m-3,which was their worst air quality in more than 50 years,nearly 10 times that of the air quality guideline(i.e.,15μg m-3)issued by the World Health Organization(WHO).Aside from the direct emissions from forest fires,the peat fires beneath the surface might smolder for several months or even longer and release substantial amounts of CO_(2).The substantial amounts of greenhouse gases from forest and peat fires might contribute to the positive feedback to the climate,potentially accelerating global warming.To better understand the comprehensive environmental effects of wildfires and their interactions with the climate system,more detailed research based on advanced observations and Earth System Models is essential.展开更多
Background and Aim: After successful medical management of a patient with a clinical picture suggestive of post-sphincterotomy duodenal perforation, in which a computerized axial tomography (CAT) scan of the abdomen r...Background and Aim: After successful medical management of a patient with a clinical picture suggestive of post-sphincterotomy duodenal perforation, in which a computerized axial tomography (CAT) scan of the abdomen revealed the presence of subcutaneous emphysema and retroperitoneal air, concern arose as to the frequency of pneumoretroperitoneum following endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy (ES) and if any procedure dependent factors were associated with this problem. Aim: To assess the frequency and clinical significance of retroperitoneal air after endoscopic retrograde cholangiopancreatography with sphincterotomy. Methods: Fifty consecutive patients, who had undergone ERCP with sphincterotomy, were submitted to abdominal CT examinations within 24 hours after completion of the procedure. One patient was with a large precut, but a failed ERCP was also included. The ERCP findings were unknown to the radiologist. Results: Seven (14%) of 50 patients showed CT findings of retroperitoneal air. All of them had uneventful post-procedural recovery. No clinical or laboratory abnormality was found in this group of patients. The presence of retroperitoneal air was not associated to the variables: precut, biliopancreatic disease type, endoscopic sphincterotomy length, additional endoscopic procedure (balloon exploration, gallstone extraction, stent insertion) or procedure duration. Conclusion: After ERCP with ES, retroperitoneal air is frequently found. In the absence of physical symptoms, retroperitoneal air is not clinically relevant and does not require specific treatment.展开更多
Reinforcement learning has been applied to air combat problems in recent years,and the idea of curriculum learning is often used for reinforcement learning,but traditional curriculum learning suffers from the problem ...Reinforcement learning has been applied to air combat problems in recent years,and the idea of curriculum learning is often used for reinforcement learning,but traditional curriculum learning suffers from the problem of plasticity loss in neural networks.Plasticity loss is the difficulty of learning new knowledge after the network has converged.To this end,we propose a motivational curriculum learning distributed proximal policy optimization(MCLDPPO)algorithm,through which trained agents can significantly outperform the predictive game tree and mainstream reinforcement learning methods.The motivational curriculum learning is designed to help the agent gradually improve its combat ability by observing the agent's unsatisfactory performance and providing appropriate rewards as a guide.Furthermore,a complete tactical maneuver is encapsulated based on the existing air combat knowledge,and through the flexible use of these maneuvers,some tactics beyond human knowledge can be realized.In addition,we designed an interruption mechanism for the agent to increase the frequency of decisionmaking when the agent faces an emergency.When the number of threats received by the agent changes,the current action is interrupted in order to reacquire observations and make decisions again.Using the interruption mechanism can significantly improve the performance of the agent.To simulate actual air combat better,we use digital twin technology to simulate real air battles and propose a parallel battlefield mechanism that can run multiple simulation environments simultaneously,effectively improving data throughput.The experimental results demonstrate that the agent can fully utilize the situational information to make reasonable decisions and provide tactical adaptation in the air combat,verifying the effectiveness of the algorithmic framework proposed in this paper.展开更多
基金the support from the Zhejiang Provincial Natural Science Foundation (No.LR22E070001),the National Natural Science Foundation of China (Nos.12275239 and 11975205)the Guangdong Basic and Applied Basic Research Foundation (No.2020B1515120048).
文摘Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma treatment.As a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V vs.reversible hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported electrocatalysts.Impressively,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling stability.First-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics rates.This work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs.
基金CDC/NIOSH for funding this research(75D30119C05529)。
文摘Control of dust in underground coal mines is critical for mitigating both safety and health hazards.For decades,the National Institute of Occupational Safety and Health(NIOSH)has led research to evaluate the effectiveness of various dust control technologies in coal mines.Recent studies have included the evaluation of auxiliary scrubbers to reduce respirable dust downstream of active mining and the use of canopy air curtains(CACs)to reduce respirable dust in key operator positions.While detailed dust characterization was not a focus of such studies,this is a growing area of interest.Using preserved filter samples from three previous NIOSH studies,the current work aims to explore the effect of two different scrubbers(one wet and one dry)and a roof bolter CAC on respirable dust composition and particle size distribution.For this,the preserved filter samples were analyzed by thermogravimetric analysis and/or scanning electron microscopy with energy dispersive X-ray.Results indicate that dust composition was not appreciably affected by either scrubber or the CAC.However,the wet scrubber and CAC appeared to decrease the overall particle size distribution.Such an effect of the dry scrubber was not consistently observed,but this is probably related to the particular sampling location downstream of the scrubber which allowed for significant mixing of the scrubber exhaust and other return air.Aside from the insights gained with respect to the three specific dust control case studies revisited here,this work demonstrates the value of preserved dust samples for follow-up investigation more broadly.
文摘To solve the problem that utilizing an air rower lowers indoor air quality due to the dust stirred up in the course of rowing, an air rower is designed to have the extra function of air purifying. The designed rower is composed of six parts, which are the frame, air generator, transmission part, air purifying filter cartridge, performance monitor, and electric motor. To fulfill the task, the filter cartridge is vertically arranged to lead the air to enter from the lower part and vent out of the upper part to filter and purify the air before it enters the generator so as that the indoor air is well circulated to improve the air purification effect when the rower is utilizing. The modular detachable design allows the air filter and electric motor to be installed and disassembled to adapt to different air purification needs. The designed rower has the benefit of lower purchasing cost and energy saving that may motivate exercising, bringing more fun and the sense of accomplishment.
基金supported by the National Nature Science Foundation of China(Grant No.50906079)the 100 Talents Program of Chinese Academy of Sciences
文摘Air cannon is a kind of de-clogging device which produces impulse force by instantly releasing the compressed air deposited in a pressure vessel. Air cannons are widely used in the transport pipes of warehouses, docks, furnaces and coal mines. In this paper, the theoretical analysis with isentropic flow hypothesis is firstly conducted on a simplified mode/ to deduce the theo- retical maximum of impulse force. And numerical study is carried out to predict the steady and unsteady impulse forces via simulating the whole exhausting process of the air cannon. The results demonstrate that the impulse force can be improved via increasing the piston sleeve inlet length and increasing the nozzle diameter. Laval nozzle can also increase the impulse force of the air without increasing the air mass flow. The optimization of the air cannon is then conducted on the basis of the theoretical and numerical analyses. Experimental measurements indicate that the computations well simulate the working process of the air cannon and the impulse force of the optimized design is 50% higher than the original model. For the cases with working pressure of 0.8 MPa, the optimized design is 60% higher than the original one.
基金Supported by National Key Project of Scientific and Technical Support-ing Programs Funded by Ministry of Science & Technology of China during the11thFive-Year Plan Period"Study on Monitoring,Early Warning and Control Techniques of Major Agricultural Meteorological Disasters--Study on Monitoring and Early Warning Techniques of Chilling Injury in South China"(2006BAD04B03)Subject of National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Tech-nology of China"Study on Chilling and Freezing Injuries Assessment,Mo-nitoring and Warning Techniques of Main Subtropical Crops"(2008BADB8B01)~~
文摘[Objective] The study aimed to provide supports for developing chilling and freezing injury monitoring and disaster damage assessment of longan(Dimocarpus Longan Lour.).[Method] Based on field observation data,the relationships between longan canopy temperature and air temperature under different weather types(sunny,cloudy to sunny,cloudy,rainy,radiation chilling injury and advection chilling injury)in 2007-2008 winter were analyzed.[Result] Diurnal variations of longan canopy temperature under sunny and radiation chilling injury weather conditions were most dramatic,followed with those under cloudy to sunny condition,while variations under cloudy,rainy and advection chilling injury conditions were mild.Diurnal variations of orchard air temperature were also closely related to weather types.By using linear and curvilinear regression methods,the relationship models between longan canopy temperature and observation station air temperature were established.The models for cloudy,rainy and advection chilling injury had better effects than those for sunny,cloudy to sunny and radiation chilling injury;the models for night were better than those for daytime and the whole day.[Conclusion] To some extent,applying the relationship models between longan canopy temperature and observation station air temperature could make up the shortcoming of meteorological data which were higher than the real values.
基金supported by the National Key Research and Development Program of China (Grant No. 2016YFC0905501)the National Natural Science Funds for Distinguished Young Scholar (Grant No. 81425025)+3 种基金the Key Project of the National Natural Science Foundation of China (Grant No. 81830093)the CAMS Innovation Fund for Medical Sciences (Grant No. CIFMS 2019-I2M-1-003)the National Natural Science Foundation of China (Grant No. 81672765)
文摘Each year there will be an estimated 2.1 million new lung cancer cases and 1.8 million lung cancer deaths worldwide.Tobacco smoke is the No.1 risk factors of lung cancer,accounting for>85%lung cancer deaths.Air pollution,or haze,comprises ambient air pollution and household air pollution,which are reported to cause 252,000 and 304,000 lung cancer deaths each year,respectively.Tobacco smoke and haze(hereafter,smohaze)contain fine particles originated from insufficient combustion of biomass or coal,have quite similar carcinogens,and cause similar diseases.Smohaze exert hazardous effects on exposed populations,including induction of a large amount of mutations in the genome,alternative splicing of mRNAs,abnormalities in epigenomics,initiation of tumor-promoting chronic inflammation,and facilitating immune escape of transformed cells.Tackling smohaze and development of multi-targets-based preventive and therapeutic approaches targeting smohaze-induced carcinogenesis are the key to conquer lung cancer in the future.
文摘Testing was completed on an earlier roof bolter CAC that used slots to provide a perimeter airflow. NIOSH tested it due to its unique design that differed from canopies that provided uniform airflow. Based upon NIOSH recommendations from the earlier testing, a 3rd generation roof bolter CAC has been developed by J.H. Fletcher & Co. The changes to this CAC involve design modifications to the plenum outlets, using a single row of outlets on the perimeter and a different material for the plenum. This laboratory testing was a continuation of the original perimeter slotted CAC design. Using gravimetric and instantaneous sampling of respirable dust concentrations underneath and outside of the CAC. the laboratory testing was completed using three different blower fans that delivered differing airflows. The maximum plenum airflow velocities ranged from 2.34 to 3.64 m/s (460-716 fpm). Results showed plenum respirable dust concentrations ranging from 34.6% to 49.3% lower than respirable dust concentrations outside the plenum protection zone, thus showing an improvement in protection for the roof bolter operators.
基金supported by the National Natural Science Foundation of China (Grant No. 41305089)the National Oceanic and Atmospheric Administration (Grant No. NA10NES4400013)the Public Industry-specific Fund for Meteorology (Grant No. GYHY201406011)
文摘Atmospheric InfraRed Sounder (AIRS) measurements are a valuable supplement to current observational data,especially over the oceans where conventional data are sparse.In this study,two types of AIRS-retrieved temperature and moisture profiles,the AIRS Science Team product (SciSup) and the single field-of-view (SFOV) research product,were evaluated with European Centre for Medium-Range Weather Forecasts (ECMWF) analysis data over the Atlantic Ocean during Hurricane Ike (2008) and Hurricane Irene (2011).The evaluation results showed that both types of AIRS profiles agreed well with the ECMWF analysis,especially between 200 hPa and 700 hPa.The average standard deviation of both temperature profiles was approximately 1 K under 200 hPa,where the mean AIRS temperature profile from the AIRS SciSup retrievals was slightly colder than that from the AIRS SFOV retrievals.The mean SciSup moisture profile was slightly drier than that from the SFOV in the mid troposphere.A series of data assimilation and forecast experiments was then conducted with the Advanced Research version of the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system for hurricanes Ike and Irene.The results showed an improvement in the hurricane track due to the assimilation of AIRS clear-sky temperature profiles in the hurricane environment.In terms of total precipitable water and rainfall forecasts,the hurricane moisture environment was found to be affected by the AIRS sounding assimilation.Meanwhile,improving hurricane intensity forecasts through assimilating AIRS profiles remains a challenge for further study.
文摘Canopy air curtain (CAC) technology has been developed by the National Institute for Occupational Safety and Health (NIOSH) for use on continuous miners and subsequently roof bolting machines in underground coal mines to protect operators of these machines from overexposure to respirable coal mine dust. The next logical progression is to develop a CAC for shuttle cars to protect operators from the same overexposures. NIOSH awarded a contract to Marshall University and J.H. Fletcher to develop the shuttle car CAC. NIOSH conducted laboratory testing to determine the dust control efficiency of the shuttle car CAC. Testing was conducted on two different cab configurations: a center drive similar to that on a Joy 10SC32AA cab model and an end drive similar to that on a Joy 10SC32AB cab model. Three different ventilation velocities were tested-0.61, 2.0, 4.3 rrds (120, 400, and 850 fpm). The lowest, 0.61 m/s (120 fpm), represented the ventilation velocity encountered during loading by the continuous miner, while the 4.3 m/s (850 fpm) velocity represented ventilation velocity airflow over the shuttle car while tramming against ventilation airflow. Test results showed an average of the dust control efficiencies ranging from 74 to 83% for 0.61 m/s (120 fpm), 39%-43% for 2.0 m/s (400 fpm), and 6%-16% for 4.3 m/s (850 fpm). Incorporating an airflow spoiler to the shuttle car CAC design and placing the CAC so that it is located 22.86 cm (9 in.) forward of the operator improved the dust control efficiency to 51%-55% for 4.3 m/s (850 fpm) with minimal impact on dust control efficiencies for lower ventilation velocities. These laboratory tests demonstrate that the newly developed shuttle car CAC has the potential to successfully protect shuttle car operators from coal mine respirable dust overexposures.
文摘A 3rd generation roof bolter canopy air curtain(CAC)has been developed and constructed by J.H.Fletcher&Co.,Inc.As with the previous generation of the CAC,this design uses the principle of providing uniform airflow across the canopy area as recommended by the National Institute for Occupational Safety and Health.The new modifications include a plenum that is constructed of a single flat aluminum plate,smaller-diameter airflow openings,and a single row of perimeter nozzles designed to prevent mine air contaminated by respirable dust from entering the CAC protection zone.Field testing was conducted on this new 3rd generation design showing reductions in coal mine respirable dust exposure for roof bolter operators.Dust control efficiencies for the CAC for the left bolter operator(intake side)ranged from approximately 26%–60%,while the efficiencies for the CAC for the right bolter operator(return side)ranged from 3%to 47%.
基金supported by the National Natural Science Foundation of China(NSFC)(Grant Nos.42075107 and 41572090)the Yueqi Scholar fund of China University of Mining and Technology(Beijing)。
文摘Epidemiological studies have suggested that inhalation exposure to indoor ambient air from coal-burning environments is causally associated with respiratory health risks.In order to explore the toxicological mechanisms behind the adverse health effects,the hemolytic activity of PM_(10)(particulate matter with an aerodynamic diameter of 10 um or less)samples collected from homes burning coal in the recognized China"cancer village"Xuanwei were evaluated and matched against their trace elemental contents.The results demonstrated that the hemolytic activity of indoor PM_(10) in coal-burning environments ranged from 4.28%to 5.24%,with a clear positive dose-response relationship.Although low dose samples exhibited a reduced hemolytic activity,PM_(10) could have a toxic effect upon people in a coal-burning indoor environment for extended time periods.The concentrations of analyzed trace elements in PM_(10) samples ranged from 6966 to 12,958 ppm.Among the analyzed elements,Zn,Ti,Ni,Cu,Pb,Ba,Mn,Cr and V were found at higher concentrations and accounted for over 95%of the total elements.The concentrations of total analyzed elements in the PM_(10) samples revealed a significant positive correlation with PM_(10) hemolytic activity.Of the analyzed elements,Zn,Pb and Cs positively correlated with hemolysis,while Li,U and V negatively correlated with the hemolysis of human red blood cells(RBCs).Therefore,the heavy metal elements could be one of the main factors responsible for the hemolytic capacity of indoor PM_(10) in coal-burning environments.
文摘Diabetes is a complex condition,and the causes are still not fully understood.However,a growing body of evidence suggests that exposure to air pollution could be linked to an increased risk of diabetes.Specifically,exposure to certain pollutants,such as particulate Matter and Ozone,has been associated with higher rates of diabetes.At the same time,air pollution has also been linked to an increased risk of thyroid cancer.While there is less evidence linking air pollution to thyroid cancer than to diabetes,it is clear that air pollution could have severe implications for thyroid health.Air pollution could increase the risk of diabetes and thyroid cancer through several mechanisms.For example,air pollution could increase inflammation in the body,which is linked to an increased risk of diabetes and thyroid cancer.Air pollution could also increase oxidative stress,which is linked to an increased risk of diabetes and thyroid cancer.Additionally,air pollution could increase the risk of diabetes and thyroid cancer by affecting the endocrine system.This review explores the link between diabetes and air pollution on thyroid cancer.We will discuss the evidence for an association between air pollution exposure and diabetes and thyroid cancer,as well as the potential implications of air pollution for thyroid health.Given the connections between diabetes,air pollution,and thyroid cancer,it is essential to take preventive measures to reduce the risk of developing the condition.
基金CONICETPICT 468(ANPCYT) for providing financial support to this research project
文摘The marine sediments of the area of Verde Peninsula - Jabali Island (39°28'S/62°19%V-40°28' S/62°11'W) Holocene in age (3-2 ky), and modern beaches contain a significant amount of bioeroded mollusc shells. Fifteen sites were analyzed, in which 20.11% of the mollusc shells (2168 valves) presented bioerosion traces, in 54 species (30 bivalves and 24 gastropods). Fourteen ichnogenera were reported: Entobia, Maeandropolydora, Iramena, Caulostrepsis, Pennatichnus, Pinaceocladichnus, Trypanites, and Gastrochaenolites (Domichnia), Gnathichnus and Radulichnus (Pascichnia), Finichnus and Centrichnus (Fixichnia), Oichnus (Praedicnia) (macrobioerosion), y Semidendrina (microbioerosion), the latter is first reported in mollusc shells in Argentina. Eleven ichnospecies were identified Finichnus peristroma, Maeandropolydora sulcans, Gnathichnus pentax, Pinaceocladichnus onubensis, Caulostrepsis taeniola, Centrichnus eccentricus, Radulichnus inopinatus, Oichnus simplex, Oichnus paraboloides, Oichnus gradatus, and Gastrochaenolites torpedo (lithic remains). The dominant ichnogenera in the Holocene deposits are Iramena, Entobia and Oichnus. The same ichnogenera are constant with different abundance in the modern beaches, and increasing representation of Pinaceocladichnus and Pennatichnus. The dominant ichnofacies in the Holocene deposits is Trypanites, revealing a benthonic marine community composed of cheilostome bryzoans, clionaid sponges, predator gastropods, regular echinoids, polychaete annelids, bivalves, thallophytas and fungi. Generally, the area was described as a sublittoral, low-energy, stable environment with high rate of oxygenation, and sandy bottoms, with rocky bottoms at Villalonga locality.
文摘The influence of reduction in emissions on the inherent temporal characteristics of PMand NOconcentration time series in six urban cities of India is assessed by computing the Hurst exponent using Detrended Fluctuation Analysis(DFA) during the lockdown period(March 24–April 20, 2020) and the corresponding period during the previous two years(i.e., 2018 and 2019). The analysis suggests the anticipated impact of confinement on the PMand NOconcentration in urban cities, causing low concentrations. It is observed that the original PMand NOconcentration time series is persistent but filtering the time series by fitting the autoregressive process of order 1 on the actual time series and subtracting it changes the persistence property significantly. It indicates the presence of linear correlations in the PMand NOconcentrations. Hurst exponent of the PMand NOconcentration during the lockdown period and previous two years shows that the inherent temporal characteristics of the short-term air pollutant concentrations(APCs) time series do not change even after withholding the emissions. The meteorological variations also do not change over the three time periods. The finding helps in developing the prediction models for future policy decisions to improve urban air quality across cities.
基金financially supported by the National Natural Science Foundation of China(No.22179014,21603019)program for the Hundred Talents Program of Chongqing University。
文摘The electronic structures and properties of electrocatalysts,which depend on the physicochemical structure and metallic element components,could significantly affect their electrocatalytic performance and their future applications in Zn-air battery(ZAB)and overall water splitting(OWS).Here,by combining vacancies and heterogeneous interfacial engineering,three-dimensional(3D)core-shell NiCoP/NiO heterostructures with dominated oxygen vacancies have been controllably in-situ grown on carbon cloth for using as highly efficient electrocatalysts toward hydrogen and oxygen electrochemical reactions.Theoretical calculation and electrochemical results manifest that the hybridization of NiCoP core with NiO shell produces a strong synergistic electronic coupling effect.The oxygen vacancy can enable the emergence of new electronic states within the band gap,crossing the Fermi levels of the two spin components and optimizing the local electronic structure.Besides,the hierarchical core-shell NiCoP/NiO nanoarrays also endow the catalysts with multiple exposed active sites,faster mass transfer behavior,optimized electronic strutures and improved electrochemical performance during ZAB and OWS applications.
文摘Air pollution, both indoor and outdoor, has been found to be related to serious adverse health effects. Accurate estimation of air pollution exposure has become very important to suggest proper air pollution control policies and to further assess the effectiveness of these policies. In many instances, personal exposures have been found to be greater than concentrations measured at fixed site monitoring stations. As people spend most of their time indoors particularly during harsh weather conditions, it is necessary to consider indoor air quality in exposure assessment studies. The current paper focuses on the importance of personal exposure assessment based on spatial and temporal activity patters both indoors and outdoors.
基金the National Natural Science Foundation of China(Grant No.92044302)the National Key Research and Development Program(Grant Nos.2020YFA0607801,2022YFE0106500)the National Key Scientific and Technological Infrastructure project“Earth System Numerical Simulation Facility”(EarthLab).
文摘Due to the record-breaking wildfires that occurred in Canada in 2023,unprecedented quantities of air pollutants and greenhouse gases were released into the atmosphere.The wildfires had emitted more than 1.3 Pg CO_(2)and 0.14 Pg CO_(2)equivalent of other greenhouse gases(GHG)including CH4 and N_(2)O as of 31 August.The wildfire-related GHG emissions constituted more than doubled Canada’s planned cumulative anthropogenic emissions reductions in 10 years,which represents a significant challenge to climate mitigation efforts.The model simulations showed that the Canadian wildfires impacted not only the local air quality but also that of most areas in the northern hemisphere due to long-range transport,causing severe PM_(2.5)pollution in the northeastern United States and increasing daily mean PM_(2.5)concentration in northwestern China by up to 2μg m-3.The observed maximum daily mean PM_(2.5)concentration in New York City reached 148.3μg m-3,which was their worst air quality in more than 50 years,nearly 10 times that of the air quality guideline(i.e.,15μg m-3)issued by the World Health Organization(WHO).Aside from the direct emissions from forest fires,the peat fires beneath the surface might smolder for several months or even longer and release substantial amounts of CO_(2).The substantial amounts of greenhouse gases from forest and peat fires might contribute to the positive feedback to the climate,potentially accelerating global warming.To better understand the comprehensive environmental effects of wildfires and their interactions with the climate system,more detailed research based on advanced observations and Earth System Models is essential.
文摘Background and Aim: After successful medical management of a patient with a clinical picture suggestive of post-sphincterotomy duodenal perforation, in which a computerized axial tomography (CAT) scan of the abdomen revealed the presence of subcutaneous emphysema and retroperitoneal air, concern arose as to the frequency of pneumoretroperitoneum following endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy (ES) and if any procedure dependent factors were associated with this problem. Aim: To assess the frequency and clinical significance of retroperitoneal air after endoscopic retrograde cholangiopancreatography with sphincterotomy. Methods: Fifty consecutive patients, who had undergone ERCP with sphincterotomy, were submitted to abdominal CT examinations within 24 hours after completion of the procedure. One patient was with a large precut, but a failed ERCP was also included. The ERCP findings were unknown to the radiologist. Results: Seven (14%) of 50 patients showed CT findings of retroperitoneal air. All of them had uneventful post-procedural recovery. No clinical or laboratory abnormality was found in this group of patients. The presence of retroperitoneal air was not associated to the variables: precut, biliopancreatic disease type, endoscopic sphincterotomy length, additional endoscopic procedure (balloon exploration, gallstone extraction, stent insertion) or procedure duration. Conclusion: After ERCP with ES, retroperitoneal air is frequently found. In the absence of physical symptoms, retroperitoneal air is not clinically relevant and does not require specific treatment.
文摘Reinforcement learning has been applied to air combat problems in recent years,and the idea of curriculum learning is often used for reinforcement learning,but traditional curriculum learning suffers from the problem of plasticity loss in neural networks.Plasticity loss is the difficulty of learning new knowledge after the network has converged.To this end,we propose a motivational curriculum learning distributed proximal policy optimization(MCLDPPO)algorithm,through which trained agents can significantly outperform the predictive game tree and mainstream reinforcement learning methods.The motivational curriculum learning is designed to help the agent gradually improve its combat ability by observing the agent's unsatisfactory performance and providing appropriate rewards as a guide.Furthermore,a complete tactical maneuver is encapsulated based on the existing air combat knowledge,and through the flexible use of these maneuvers,some tactics beyond human knowledge can be realized.In addition,we designed an interruption mechanism for the agent to increase the frequency of decisionmaking when the agent faces an emergency.When the number of threats received by the agent changes,the current action is interrupted in order to reacquire observations and make decisions again.Using the interruption mechanism can significantly improve the performance of the agent.To simulate actual air combat better,we use digital twin technology to simulate real air battles and propose a parallel battlefield mechanism that can run multiple simulation environments simultaneously,effectively improving data throughput.The experimental results demonstrate that the agent can fully utilize the situational information to make reasonable decisions and provide tactical adaptation in the air combat,verifying the effectiveness of the algorithmic framework proposed in this paper.