This study aimed to explore the disinfection of drinking water in trunk water mains, based on published conditions denoted within the Irish Republic. The variables within the study were consumer draw-off rates, trunk ...This study aimed to explore the disinfection of drinking water in trunk water mains, based on published conditions denoted within the Irish Republic. The variables within the study were consumer draw-off rates, trunk main length, pipe diameter, and water temperature. All these factors are known to impact the free chlorine residual in operational supply networks. Based on published conditions obtained within the literature review, 60 hypothetical trunk mains were generated for this study. Of primary concern were the variables that affect the chlorine decay rate;total amount of chlorine decay;available amount of chlorine in the periphery of the trunk main;and the costs associated with effective chlorine disinfection of trunk mains. Based on the analysis performed, the following were the salient observations: 1) Low consumer draw-off rates and increased trunk main length and diameter increased the risk of the free chlorine residual in the periphery of the trunk mains not complying with the Environmental Protection Agency’s (EPA) minimum recommended residual value of 0.1 mg/l (EPA Drinking Water Audit Report, 2014). 2) Increasing the diameter of the trunk main from 125 mm to 180 mm had a negligible effect on the chlorine decay rate. However, increasing the trunk main diameter from 125 mm to 180 mm was shown to have a major impact on the total amount of chlorine decay and free chlorine residual available in the periphery of the main. The key parameters that affected disinfection costs associated with trunk mains include length, diameter and the need for chlorine boosting.展开更多
With net zero carbon emissions targets approaching over the next 20 to 30 years, the water industry must act now to develop energy efficient techniques and designs to reduce emissions and reduce the carbon footprint o...With net zero carbon emissions targets approaching over the next 20 to 30 years, the water industry must act now to develop energy efficient techniques and designs to reduce emissions and reduce the carbon footprint of water utility providers. There is also the potential for significant energy and therefore financial savings to be realised from the adoption of more energy efficient designs approaches. Water utility providers account for a significant proportion of national electricity consumption. The purpose of this research is to determine if, over the long term, opting for a larger diameter pipe at design stage can lead to significant financial and emissions savings for water utility providers when considering pumping mains. Pumping mains are widely used throughout the water and wastewater industry where a gravity solution is not possible. 72 hypothetical water main design scenarios were analysed and the long term financial and environmental impact of each hypothetical water main was assessed. It was found across all design scenarios that larger diameter water mains were capable of delivering the same rate of flow of smaller diameter pipes at a much reduced velocity and requiring reduced pumping power. It was concluded that pumped mains of larger diameters can ultimately be more energy efficient and cost effective over the long term when selected in favour of smaller diameter pumped mains in otherwise identical design scenarios.展开更多
选取华东师范大学儿童语言研究中心zhou2语料库中的400名3-5岁学前儿童作为研究对象,运用国际叙事语言评估工具——MAIN(Multilingual Assessment Instrument for Narratives)中《鸟》的故事作为研究材料进行数据收集,并使用MAIN从故事...选取华东师范大学儿童语言研究中心zhou2语料库中的400名3-5岁学前儿童作为研究对象,运用国际叙事语言评估工具——MAIN(Multilingual Assessment Instrument for Narratives)中《鸟》的故事作为研究材料进行数据收集,并使用MAIN从故事结构、结构复杂性、内部状态术语、故事理解四个方面,重点考察3-5岁学前儿童讲述故事的叙事能力,以及各要素的叙事水平是否存在年龄差异。结果表明:儿童叙事能力随年龄增长呈不均衡发展态势,且4-5岁为儿童叙事能力发展的转折期;儿童对故事各要素讲述能力的发展具有显著年龄差异;儿童故事理解能力各要素均处于较低发展水平。展开更多
It is known that homogeneous bounded domains are holomorphic isomorphic to N-Siegel domains, in order to compute the holomorphic sectional curvatures of the homogeneous bounded domains, one needs only to compute the h...It is known that homogeneous bounded domains are holomorphic isomorphic to N-Siegel domains, in order to compute the holomorphic sectional curvatures of the homogeneous bounded domains, one needs only to compute the holomorphic展开更多
The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible flow.The reflection of the primary s...The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible flow.The reflection of the primary shock and its propagation within a confined domain are studied both theoretically and numerically in this research.Under the assumption of strong shock,the scaling law governing propagation of the main shock is proposed.The dimensionless frequency of reflected shock propagation is associated with the confined distance.The numerical simulation for the circular explosion problem in a confined domain is performed for validation.Under the influence of confinement,the principal shock wave systematically undergoes reflection within the domain until it weakens,leading to the non-monotonic attenuation of kinetic energy in the explosion fireball and periodic oscillations of the fireball volume with a certain frequency.The simulation results indicate that the frequency of kinetic energy attenuation and the volume oscillation of the explosive fireball align consistently with the scaling law.展开更多
The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and structures.The highresolution marine seismic explora...The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and structures.The highresolution marine seismic exploration based on a high broadband sparker source is an important approach to reveal seabed stratum and reservoir structure,and identify geohazard.To optimize the performance of sparker seismic source,we investigated the electro-acoustic characteristics of spark discharge under conditions of different charging voltages and electrode numbers.Results show that the sound source level increased with the increase of the charging voltage,whereas the main frequency decreased when the charging voltage increases.In addition,it was found that the charging capacitance had more obvious influence on the main frequency than the sound source level did.Although the load energy decreased with increasing electrode number,the sound source level still increased but the main frequency decreased.Meanwhile,the primary to bubble(P/B)ratio increased with the increase of the electrode number.To gain a deeper insight into the electro-acoustic characteristics,we investigate the relationship between sound source level and power peak,from which a good correlation was observed.A more practical statistical analysis on the rise rate of current was processed,and a perfect logarithmic function was derived.Furthermore,we found that the main frequency was most possibly subjected to the electrical energy,especially the charging energy per electrode.The results indicate that the charging energy per electrode less than 10 J could increase the main frequency to above 300 Hz.At last,the main frequency could be reduced to 20 Hz when the charging energy of a single-electrode discharge was enhanced to over 4 kJ.This study shall be helpful in developing a sparker seismic source and improving the performance for marine engineering exploration and geohazard assessment.展开更多
Based on the geochemical,seismic,logging and drilling data,the Fuyu reservoirs of the Lower Cretaceous Quantou Formation in northern Songliao Basin are systematically studied in terms of the geological characteristics...Based on the geochemical,seismic,logging and drilling data,the Fuyu reservoirs of the Lower Cretaceous Quantou Formation in northern Songliao Basin are systematically studied in terms of the geological characteristics,the tight oil enrichment model and its major controlling factors.First,the Quantou Formation is overlaid by high-quality source rocks of the Upper Cretaceous Qingshankou Formation,with the development of nose structure around sag and the broad and continuous distribution of sand bodies.The reservoirs are tight on the whole.Second,the configuration of multiple elements,such as high-quality source rocks,reservoir rocks,fault,overpressure and structure,controls the tight oil enrichment in the Fuyu reservoirs.The source-reservoir combination controls the tight oil distribution pattern.The pressure difference between source and reservoir drives the charging of tight oil.The fault-sandbody transport system determines the migration and accumulation of oil and gas.The positive structure is the favorable place for tight oil enrichment,and the fault-horst zone is the key part of syncline area for tight oil exploration.Third,based on the source-reservoir relationship,transport mode,accumulation dynamics and other elements,three tight oil enrichment models are recognized in the Fuyu reservoirs:(1)vertical or lateral migration of hydrocarbon from source rocks to adjacent reservoir rocks,that is,driven by overpressure,hydrocarbon generated is migrated vertically or laterally to and accumulates in the adjacent reservoir rocks;(2)transport of hydrocarbon through faults between separated source and reservoirs,that is,driven by overpressure,hydrocarbon migrates downward through faults to the sandbodies that are separated from the source rocks;and(3)migration of hydrocarbon through faults and sandbodies between separated source and reservoirs,that is,driven by overpressure,hydrocarbon migrates downwards through faults to the reservoir rocks that are separated from the source rocks,and then migrates laterally through sandbodies.Fourth,the differences in oil source conditions,charging drive,fault distribution,sandbody and reservoir physical properties cause the differential enrichment of tight oil in the Fuyu reservoirs.Comprehensive analysis suggests that the Fuyu reservoir in the Qijia-Gulong Sag has good conditions for tight oil enrichment and has been less explored,and it is an important new zone for tight oil exploration in the future.展开更多
Based on the daily meteorological observation data of seven meteorological stations in southern Tibet from 1980 to 2021 (April-October), the temporal and spatial variation characteristics and influencing factors of ar...Based on the daily meteorological observation data of seven meteorological stations in southern Tibet from 1980 to 2021 (April-October), the temporal and spatial variation characteristics and influencing factors of aridity index ( AI ) in the growing season of major grain producing areas in Tibet were studied by using climate tendency rate, Mann-Kendal test, Morlet wavelet analysis, GIS hybrid interpolation method, Pearson correlation coefficient, contribution rate analysis and other methods. The results showed that the average AI in the main grain producing areas of Tibet was 1.7, which belonged to the semi-arid area, and the overall trend was decreasing (humidifying) (-0.036/10 a). The linear decreasing trend was different in different regions, and the area around Lhatse County was the most significant (-0.26/10 a). AI had no obvious abrupt change, and had long- and medium-term fluctuation characteristics of 24 years, 6 years. The spatial distribution was uneven, and had the characteristics of ‘shrinking arid area and expanding humid area . The contribution rates of the main climate influencing factors of AI varied in different regions. In general, the contribution rates after quantification was as follows: precipitation (34.9%)>relative humidity (28.4%)>sunshine (19.9%)>maximum temperature (12.4%).展开更多
Objective: The aim was to show that Minimally Invasive total arterial revascularization for left main stem coronary artery disease, via a left anterior Mini thoracotomy using bilateral internal thoracic arteries is fe...Objective: The aim was to show that Minimally Invasive total arterial revascularization for left main stem coronary artery disease, via a left anterior Mini thoracotomy using bilateral internal thoracic arteries is feasible, reproducible and safe. Further, there has been no exclusive data or experience with minimally invasive coronary artery bypass grafting in left main stem disease. Methods: From April 2019 to March 2024, 41 patients with left main stem stenosis, left main equivalent disease and unprotected left main with triple vessel disease underwent off pump minimally invasive multivessel coronary artery bypass grafting using either in situ pedicled Bilateral Internal Thoracic arteries or Left and Right Internal Thoracic artery Y composite conduits at three centers. Bilateral Internal Thoracic arteries were harvested under direct vision. All patients had an Intra-Aortic Balloon Pump inserted via the femoral artery prior to induction of anesthesia, to prevent any hemodynamic instability, arrhythmias, and was removed following completion of the procedure in the operating room without any complications. Efficacy and outcomes were evaluated by i) Primary (MACCE)-Major Adverse Cardiac and Cardiovascular events and ii) Secondary outcome measures including total length of stay, return to full physical activity and quality of life. Mean follow-up was 1.4 years (Maximum was 2.5 years). Results: 41 patients with left main stem coronary artery stenosis, underwent total arterial revascularization using bilateral internal thoracic arteries. Left main stem stenosis was present in 29 patients, Unprotected left main stem stenosis with triple vessel disease in 7 and left main equivalence in 5 patients. In this cohort, 29 patients with only left main stem stenosis had 2 grafts each, 7 patients with left main and triple vessel disease had 3 grafts and 5 patients with left main equivalent disease had 2 grafts respectively. The average number of grafts was 2.2. One patient was converted to open sternotomy as an emergency because of hemodynamic instability and myocardial revascularization was done on cardiopulmonary bypass (2.2%). The average hospital stay was 3.7 days. Ejection fraction was 45% ± 5%. There was one mortality (2.2%) but no major morbidity. The average ICU and hospital stay was 24 ± 4 hours and 3.7 days. All patients were free from major adverse cardiac and cerebrovascular events at follow-up. Conclusions: Multivessel total arterial revascularization using left and right internal thoracic arteries, was performed via a left anterior Mini thoracotomy on patients with left main stem disease and showed that it was safe, reproducible and will help extend the armamentarium of the surgeon in minimally invasive Coronary artery bypass grafting. Concomitantly it helped enhance the potential for shorter hospital stay, increased survival, decreased morbidity, and earlier return to full activity. Furthermore, the safety, efficacy, and outcomes of minimally invasive coronary artery bypass grafting in this high-risk group evaluated by primary and secondary outcome measures have been good in this study.展开更多
Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road du...Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road dust suppressants is also progressing.To promote the rational application and development of road dust suppressants,the research progress and prospects of them are analyzed in this paper.It includes a basic overview of road dust suppressants,the main types,the usage and precautions,and the main development direction.It is hoped that this analysis can provide some reference for further research and development of road dust suppressants.展开更多
This topic is closely centered on exploring how Chinese fine arts can take the road to the healthy development of art,which is of great guiding significance.It is clear that the road of national art development is to ...This topic is closely centered on exploring how Chinese fine arts can take the road to the healthy development of art,which is of great guiding significance.It is clear that the road of national art development is to carry forward the main theme,promote social justice,guide and infect people with correct public opinion,and better serve the people with excellent works.展开更多
The article hypothesizes that DE and DM (UCM) are a “Form of Motion of a Special Nature”, where “Form of Motion” means “Eternal Motion” as the power of dynamics of different levels and varying degrees of self-su...The article hypothesizes that DE and DM (UCM) are a “Form of Motion of a Special Nature”, where “Form of Motion” means “Eternal Motion” as the power of dynamics of different levels and varying degrees of self-sufficiency, and by “Special Nature”, gravitational and two other properties of matter, “tied” to the “Eternal Movement” and completely dependent on it. Carriers of key properties of a “Special Nature” have been established: “0”-DE particles and “3”-DM particles (UDM). The unity of their inherent “motionally-gravitational” properties and the peculiarity of the relationship between “motion” and “gravity” are revealed: the higher the intensity of “Eternal Motion”, the stronger the gravitational properties of matter are manifested (and vice versa). The relationship of “time” with the “vibration frequency” and the “mass” of photons with the “degree of bonding and deformation properties of the field” is shown. The maximum level of gravity has been determined, which allows Nature to successfully create the Universe: such a landmark is the proximity to the property of the Primary Source—the “pure graviton” of the OSP space, the most powerful “motionally-gravitational” particle of the Universe. The reasons for the emergence of such an identity of the gravitational properties of particles with the indicators of a “pure graviton” are established: for “0”-DE particles, this is the acquisition of the function of “freedom of movement”;for “3”-DM particles (UDM), the creation of a special structure—a “double field” (“Main” and “Small”). The presence in the “double field” of specific “tools” for the creation of the worlds of the Universe—gravitational “waves” gives rise to impulses (shocks) of varying intensity and shape. A list of functions performed by “waves” in the “Main” and “Small” fields has been compiled. The specific conditions for the formation of “UDM Streams”, their transformation into a “Vortex” and, under the influence of a powerful Initial Impulse (push), sending them to the “place” of the creation of galaxies, are shown. It is suggested that there is a “Cycle of Matter in Nature” in the closed structure of our Universe due to the “work” of “waves” and the functioning of special “factories” in the form of exotic space objects—Black holes.展开更多
Faced with the continuous occurrence of coal and gas outburst(hereinafter referred to as“outburst”)disasters,as a main controlling factor in the evolution process of an outburst,for gas pressure,it is still unclear ...Faced with the continuous occurrence of coal and gas outburst(hereinafter referred to as“outburst”)disasters,as a main controlling factor in the evolution process of an outburst,for gas pressure,it is still unclear about the phased characteristics of the coupling process with in situ stress,which induce coal damage and instability.Therefore,in the work based on the mining stress paths induced by typical outburst accidents,the gradual and sudden change of three-dimensional stress is taken as the background for the mechanical reconstruction of the disaster process.Then the true triaxial physical experiments are conducted on the damage and instability of coal containing gas under multiple stress paths.Finally,the response characterization between coal damage and gas pressure has been clarified,revealing the mechanism of action of gas pressure during the initial failure of coals.And the main controlling mechanism during the outburst process is elucidated in the coupling process of in situ stress with gas pressure.The results show that during the process of stress loading and unloading,the original gas pressure enters the processes of strengthening and weakening the action ability successively.And the strengthening effect continues to the period of large-scale destruction of coals.The mechanical process of gas pressure during the initial failure of coals can be divided into three stages:the enhancement of strengthening action ability,the decrease of strengthening action ability,and the weakening action ability.The entire process is implemented by changing the dominant action of in situ stress into the dominant action of gas pressure.The failure strength of coals is not only affected by its original mechanical strength,but also by the stress loading and unloading paths,showing a particularly significant effect.Three stages can be divided during outburst inoculation process.That is,firstly,the coals suffer from initial damage through the dominant action of in situ stress with synergy of gas pressure;secondly,the coals with spallation of structural division are generated through the dominant action of gas pressure with synergy of in situ stress,accompanied by further fragmentation;and finally,the fractured coals suffer from fragmentation and pulverization with the gas pressure action.Accordingly,the final broken coals are ejected out with the gas action,initiating an outburst.The research results can provide a new perspective for deepening the understanding of coal and gas outburst mechanism,laying a theoretical foundation for the innovation of outburst prevention and control technologies.展开更多
A new algorithm is proposed to solve the problems of shape-finding of suspension bridge with spatial cables what include tedious iteration,slow convergence speed and even no convergent under some circumstances.In this...A new algorithm is proposed to solve the problems of shape-finding of suspension bridge with spatial cables what include tedious iteration,slow convergence speed and even no convergent under some circumstances.In this paper,the stress analysis of the main cable is carried out,and the relationship between the slope change and the coordinate change is found.This paper also discussed how to find the minimum slope point of symmetrical or asymmetric main cable,and the deformation compatibility equation is established and solved to obtain the shape of main cable.The algorithm in this paper can ensure the convergence of the solution for the suspension bridge with spatial cables.The calculation accuracy is high through the demonstration of the calculation examples.展开更多
We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the p...We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the precision of the model,we considered the data gap between the ground and satellite data.We compared and analyzed the results of the Taylor polynomial,surface Spline,and CHAOS-6(the CHAMP,?rsted and SAC-C model of Earth’s magnetic field)gradient models.Results showed that the gradients in the south-north and east-west directions of the four models were consistent.The 3DSS model was able to express not only gradients at different altitudes,but also average gradients inside the research area.The two Spline models were able to capture more information on gradient anomalies than were the fitted models.Strong local anomalies were observed in northern Xinjiang,Beijing,and the junction area between Jiangsu and Zhejiang,and the total intensity F decreased whereas the altitude increased.The gradient decreased by 21.69%in the south-north direction and increased by 11.78%in the east-west direction.In addition,the altitude gradient turned from negative to positive while the altitude increased.The Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory.展开更多
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geolog...Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.展开更多
Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding re...Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.展开更多
Left main coronary compression syndrome(LMCS)may complicate pulmonary artery aneurysms(PAA),usually developed in the context of pulmonary arterial hypertension(PAH).We report the case of a 51-year-old female patient w...Left main coronary compression syndrome(LMCS)may complicate pulmonary artery aneurysms(PAA),usually developed in the context of pulmonary arterial hypertension(PAH).We report the case of a 51-year-old female patient with an atrial septal defect(unsuitable for device closure)complicated by a PAA generating a 90%left main stenosis.The significant PAH held us back from immediate surgery.After specific dual PAH-targeted therapy(sildenafil and bosentan),the atrial septal defect could be closed with a unidirectional valved patch;the PAAinduced LMCS was treated by reductive arterioplasty.The postoperative course was uneventful.Follow-up showed clinical improvement,but PAH treatment was still needed.After three months,coronary angiography showed only an insignificant residual left main stenosis,proving that reductive pulmonary arterioplasty was effective in treating LMCS.Any PAA requires further evaluation for LMCS,a dangerous but treatable complication.The“treat-repair-treat”strategy and shunt-closure with a unidirectional valved patch can both improve surgical prospects of LMCS with shunt-related PAH.展开更多
文摘This study aimed to explore the disinfection of drinking water in trunk water mains, based on published conditions denoted within the Irish Republic. The variables within the study were consumer draw-off rates, trunk main length, pipe diameter, and water temperature. All these factors are known to impact the free chlorine residual in operational supply networks. Based on published conditions obtained within the literature review, 60 hypothetical trunk mains were generated for this study. Of primary concern were the variables that affect the chlorine decay rate;total amount of chlorine decay;available amount of chlorine in the periphery of the trunk main;and the costs associated with effective chlorine disinfection of trunk mains. Based on the analysis performed, the following were the salient observations: 1) Low consumer draw-off rates and increased trunk main length and diameter increased the risk of the free chlorine residual in the periphery of the trunk mains not complying with the Environmental Protection Agency’s (EPA) minimum recommended residual value of 0.1 mg/l (EPA Drinking Water Audit Report, 2014). 2) Increasing the diameter of the trunk main from 125 mm to 180 mm had a negligible effect on the chlorine decay rate. However, increasing the trunk main diameter from 125 mm to 180 mm was shown to have a major impact on the total amount of chlorine decay and free chlorine residual available in the periphery of the main. The key parameters that affected disinfection costs associated with trunk mains include length, diameter and the need for chlorine boosting.
文摘With net zero carbon emissions targets approaching over the next 20 to 30 years, the water industry must act now to develop energy efficient techniques and designs to reduce emissions and reduce the carbon footprint of water utility providers. There is also the potential for significant energy and therefore financial savings to be realised from the adoption of more energy efficient designs approaches. Water utility providers account for a significant proportion of national electricity consumption. The purpose of this research is to determine if, over the long term, opting for a larger diameter pipe at design stage can lead to significant financial and emissions savings for water utility providers when considering pumping mains. Pumping mains are widely used throughout the water and wastewater industry where a gravity solution is not possible. 72 hypothetical water main design scenarios were analysed and the long term financial and environmental impact of each hypothetical water main was assessed. It was found across all design scenarios that larger diameter water mains were capable of delivering the same rate of flow of smaller diameter pipes at a much reduced velocity and requiring reduced pumping power. It was concluded that pumped mains of larger diameters can ultimately be more energy efficient and cost effective over the long term when selected in favour of smaller diameter pumped mains in otherwise identical design scenarios.
文摘选取华东师范大学儿童语言研究中心zhou2语料库中的400名3-5岁学前儿童作为研究对象,运用国际叙事语言评估工具——MAIN(Multilingual Assessment Instrument for Narratives)中《鸟》的故事作为研究材料进行数据收集,并使用MAIN从故事结构、结构复杂性、内部状态术语、故事理解四个方面,重点考察3-5岁学前儿童讲述故事的叙事能力,以及各要素的叙事水平是否存在年龄差异。结果表明:儿童叙事能力随年龄增长呈不均衡发展态势,且4-5岁为儿童叙事能力发展的转折期;儿童对故事各要素讲述能力的发展具有显著年龄差异;儿童故事理解能力各要素均处于较低发展水平。
文摘It is known that homogeneous bounded domains are holomorphic isomorphic to N-Siegel domains, in order to compute the holomorphic sectional curvatures of the homogeneous bounded domains, one needs only to compute the holomorphic
基金the National Natural Science Foundation of China(Nos.11988102,92052201,11825204,12032016,12372220,and 12372219)。
文摘The circular explosion wave produced by the abrupt discharge of gas from a high-temperature heat source serves as a crucial model for addressing explosion phenomena in compressible flow.The reflection of the primary shock and its propagation within a confined domain are studied both theoretically and numerically in this research.Under the assumption of strong shock,the scaling law governing propagation of the main shock is proposed.The dimensionless frequency of reflected shock propagation is associated with the confined distance.The numerical simulation for the circular explosion problem in a confined domain is performed for validation.Under the influence of confinement,the principal shock wave systematically undergoes reflection within the domain until it weakens,leading to the non-monotonic attenuation of kinetic energy in the explosion fireball and periodic oscillations of the fireball volume with a certain frequency.The simulation results indicate that the frequency of kinetic energy attenuation and the volume oscillation of the explosive fireball align consistently with the scaling law.
基金Supported by the National Natural Science Foundation of China(No.42276195)the Natural Science Foundation of Zhejiang Province(No.LQ22D060006)the Science Foundation of Zhejiang Sci-Tech University(No.21022092-Y)。
文摘The construction of major marine infrastructure projects and the exploration and development of deep-sea mineral resources require fine imaging of seabed strata and structures.The highresolution marine seismic exploration based on a high broadband sparker source is an important approach to reveal seabed stratum and reservoir structure,and identify geohazard.To optimize the performance of sparker seismic source,we investigated the electro-acoustic characteristics of spark discharge under conditions of different charging voltages and electrode numbers.Results show that the sound source level increased with the increase of the charging voltage,whereas the main frequency decreased when the charging voltage increases.In addition,it was found that the charging capacitance had more obvious influence on the main frequency than the sound source level did.Although the load energy decreased with increasing electrode number,the sound source level still increased but the main frequency decreased.Meanwhile,the primary to bubble(P/B)ratio increased with the increase of the electrode number.To gain a deeper insight into the electro-acoustic characteristics,we investigate the relationship between sound source level and power peak,from which a good correlation was observed.A more practical statistical analysis on the rise rate of current was processed,and a perfect logarithmic function was derived.Furthermore,we found that the main frequency was most possibly subjected to the electrical energy,especially the charging energy per electrode.The results indicate that the charging energy per electrode less than 10 J could increase the main frequency to above 300 Hz.At last,the main frequency could be reduced to 20 Hz when the charging energy of a single-electrode discharge was enhanced to over 4 kJ.This study shall be helpful in developing a sparker seismic source and improving the performance for marine engineering exploration and geohazard assessment.
基金Supported by the PetroChina Science and Technology Major Project(2016E0201)。
文摘Based on the geochemical,seismic,logging and drilling data,the Fuyu reservoirs of the Lower Cretaceous Quantou Formation in northern Songliao Basin are systematically studied in terms of the geological characteristics,the tight oil enrichment model and its major controlling factors.First,the Quantou Formation is overlaid by high-quality source rocks of the Upper Cretaceous Qingshankou Formation,with the development of nose structure around sag and the broad and continuous distribution of sand bodies.The reservoirs are tight on the whole.Second,the configuration of multiple elements,such as high-quality source rocks,reservoir rocks,fault,overpressure and structure,controls the tight oil enrichment in the Fuyu reservoirs.The source-reservoir combination controls the tight oil distribution pattern.The pressure difference between source and reservoir drives the charging of tight oil.The fault-sandbody transport system determines the migration and accumulation of oil and gas.The positive structure is the favorable place for tight oil enrichment,and the fault-horst zone is the key part of syncline area for tight oil exploration.Third,based on the source-reservoir relationship,transport mode,accumulation dynamics and other elements,three tight oil enrichment models are recognized in the Fuyu reservoirs:(1)vertical or lateral migration of hydrocarbon from source rocks to adjacent reservoir rocks,that is,driven by overpressure,hydrocarbon generated is migrated vertically or laterally to and accumulates in the adjacent reservoir rocks;(2)transport of hydrocarbon through faults between separated source and reservoirs,that is,driven by overpressure,hydrocarbon migrates downward through faults to the sandbodies that are separated from the source rocks;and(3)migration of hydrocarbon through faults and sandbodies between separated source and reservoirs,that is,driven by overpressure,hydrocarbon migrates downwards through faults to the reservoir rocks that are separated from the source rocks,and then migrates laterally through sandbodies.Fourth,the differences in oil source conditions,charging drive,fault distribution,sandbody and reservoir physical properties cause the differential enrichment of tight oil in the Fuyu reservoirs.Comprehensive analysis suggests that the Fuyu reservoir in the Qijia-Gulong Sag has good conditions for tight oil enrichment and has been less explored,and it is an important new zone for tight oil exploration in the future.
基金Supported by Natural Science Foundation of Tibet Autonomous Region(XZ202001ZR0082G)National Key Research and Development Program of China(2020YFA0608203)Key Research and Development of Science and Technology Program of Tibet Autonomous Region(CGZH2024000002)。
文摘Based on the daily meteorological observation data of seven meteorological stations in southern Tibet from 1980 to 2021 (April-October), the temporal and spatial variation characteristics and influencing factors of aridity index ( AI ) in the growing season of major grain producing areas in Tibet were studied by using climate tendency rate, Mann-Kendal test, Morlet wavelet analysis, GIS hybrid interpolation method, Pearson correlation coefficient, contribution rate analysis and other methods. The results showed that the average AI in the main grain producing areas of Tibet was 1.7, which belonged to the semi-arid area, and the overall trend was decreasing (humidifying) (-0.036/10 a). The linear decreasing trend was different in different regions, and the area around Lhatse County was the most significant (-0.26/10 a). AI had no obvious abrupt change, and had long- and medium-term fluctuation characteristics of 24 years, 6 years. The spatial distribution was uneven, and had the characteristics of ‘shrinking arid area and expanding humid area . The contribution rates of the main climate influencing factors of AI varied in different regions. In general, the contribution rates after quantification was as follows: precipitation (34.9%)>relative humidity (28.4%)>sunshine (19.9%)>maximum temperature (12.4%).
文摘Objective: The aim was to show that Minimally Invasive total arterial revascularization for left main stem coronary artery disease, via a left anterior Mini thoracotomy using bilateral internal thoracic arteries is feasible, reproducible and safe. Further, there has been no exclusive data or experience with minimally invasive coronary artery bypass grafting in left main stem disease. Methods: From April 2019 to March 2024, 41 patients with left main stem stenosis, left main equivalent disease and unprotected left main with triple vessel disease underwent off pump minimally invasive multivessel coronary artery bypass grafting using either in situ pedicled Bilateral Internal Thoracic arteries or Left and Right Internal Thoracic artery Y composite conduits at three centers. Bilateral Internal Thoracic arteries were harvested under direct vision. All patients had an Intra-Aortic Balloon Pump inserted via the femoral artery prior to induction of anesthesia, to prevent any hemodynamic instability, arrhythmias, and was removed following completion of the procedure in the operating room without any complications. Efficacy and outcomes were evaluated by i) Primary (MACCE)-Major Adverse Cardiac and Cardiovascular events and ii) Secondary outcome measures including total length of stay, return to full physical activity and quality of life. Mean follow-up was 1.4 years (Maximum was 2.5 years). Results: 41 patients with left main stem coronary artery stenosis, underwent total arterial revascularization using bilateral internal thoracic arteries. Left main stem stenosis was present in 29 patients, Unprotected left main stem stenosis with triple vessel disease in 7 and left main equivalence in 5 patients. In this cohort, 29 patients with only left main stem stenosis had 2 grafts each, 7 patients with left main and triple vessel disease had 3 grafts and 5 patients with left main equivalent disease had 2 grafts respectively. The average number of grafts was 2.2. One patient was converted to open sternotomy as an emergency because of hemodynamic instability and myocardial revascularization was done on cardiopulmonary bypass (2.2%). The average hospital stay was 3.7 days. Ejection fraction was 45% ± 5%. There was one mortality (2.2%) but no major morbidity. The average ICU and hospital stay was 24 ± 4 hours and 3.7 days. All patients were free from major adverse cardiac and cerebrovascular events at follow-up. Conclusions: Multivessel total arterial revascularization using left and right internal thoracic arteries, was performed via a left anterior Mini thoracotomy on patients with left main stem disease and showed that it was safe, reproducible and will help extend the armamentarium of the surgeon in minimally invasive Coronary artery bypass grafting. Concomitantly it helped enhance the potential for shorter hospital stay, increased survival, decreased morbidity, and earlier return to full activity. Furthermore, the safety, efficacy, and outcomes of minimally invasive coronary artery bypass grafting in this high-risk group evaluated by primary and secondary outcome measures have been good in this study.
文摘Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road dust suppressants is also progressing.To promote the rational application and development of road dust suppressants,the research progress and prospects of them are analyzed in this paper.It includes a basic overview of road dust suppressants,the main types,the usage and precautions,and the main development direction.It is hoped that this analysis can provide some reference for further research and development of road dust suppressants.
文摘This topic is closely centered on exploring how Chinese fine arts can take the road to the healthy development of art,which is of great guiding significance.It is clear that the road of national art development is to carry forward the main theme,promote social justice,guide and infect people with correct public opinion,and better serve the people with excellent works.
文摘The article hypothesizes that DE and DM (UCM) are a “Form of Motion of a Special Nature”, where “Form of Motion” means “Eternal Motion” as the power of dynamics of different levels and varying degrees of self-sufficiency, and by “Special Nature”, gravitational and two other properties of matter, “tied” to the “Eternal Movement” and completely dependent on it. Carriers of key properties of a “Special Nature” have been established: “0”-DE particles and “3”-DM particles (UDM). The unity of their inherent “motionally-gravitational” properties and the peculiarity of the relationship between “motion” and “gravity” are revealed: the higher the intensity of “Eternal Motion”, the stronger the gravitational properties of matter are manifested (and vice versa). The relationship of “time” with the “vibration frequency” and the “mass” of photons with the “degree of bonding and deformation properties of the field” is shown. The maximum level of gravity has been determined, which allows Nature to successfully create the Universe: such a landmark is the proximity to the property of the Primary Source—the “pure graviton” of the OSP space, the most powerful “motionally-gravitational” particle of the Universe. The reasons for the emergence of such an identity of the gravitational properties of particles with the indicators of a “pure graviton” are established: for “0”-DE particles, this is the acquisition of the function of “freedom of movement”;for “3”-DM particles (UDM), the creation of a special structure—a “double field” (“Main” and “Small”). The presence in the “double field” of specific “tools” for the creation of the worlds of the Universe—gravitational “waves” gives rise to impulses (shocks) of varying intensity and shape. A list of functions performed by “waves” in the “Main” and “Small” fields has been compiled. The specific conditions for the formation of “UDM Streams”, their transformation into a “Vortex” and, under the influence of a powerful Initial Impulse (push), sending them to the “place” of the creation of galaxies, are shown. It is suggested that there is a “Cycle of Matter in Nature” in the closed structure of our Universe due to the “work” of “waves” and the functioning of special “factories” in the form of exotic space objects—Black holes.
基金This work was financially supported by the National Natural Science Foundation of China(No.52104236)the Fundamental Research Funds for the Central Universities(No.22CX06018A)the China Postdoctoral Science Foundation(No.2020M672177).
文摘Faced with the continuous occurrence of coal and gas outburst(hereinafter referred to as“outburst”)disasters,as a main controlling factor in the evolution process of an outburst,for gas pressure,it is still unclear about the phased characteristics of the coupling process with in situ stress,which induce coal damage and instability.Therefore,in the work based on the mining stress paths induced by typical outburst accidents,the gradual and sudden change of three-dimensional stress is taken as the background for the mechanical reconstruction of the disaster process.Then the true triaxial physical experiments are conducted on the damage and instability of coal containing gas under multiple stress paths.Finally,the response characterization between coal damage and gas pressure has been clarified,revealing the mechanism of action of gas pressure during the initial failure of coals.And the main controlling mechanism during the outburst process is elucidated in the coupling process of in situ stress with gas pressure.The results show that during the process of stress loading and unloading,the original gas pressure enters the processes of strengthening and weakening the action ability successively.And the strengthening effect continues to the period of large-scale destruction of coals.The mechanical process of gas pressure during the initial failure of coals can be divided into three stages:the enhancement of strengthening action ability,the decrease of strengthening action ability,and the weakening action ability.The entire process is implemented by changing the dominant action of in situ stress into the dominant action of gas pressure.The failure strength of coals is not only affected by its original mechanical strength,but also by the stress loading and unloading paths,showing a particularly significant effect.Three stages can be divided during outburst inoculation process.That is,firstly,the coals suffer from initial damage through the dominant action of in situ stress with synergy of gas pressure;secondly,the coals with spallation of structural division are generated through the dominant action of gas pressure with synergy of in situ stress,accompanied by further fragmentation;and finally,the fractured coals suffer from fragmentation and pulverization with the gas pressure action.Accordingly,the final broken coals are ejected out with the gas action,initiating an outburst.The research results can provide a new perspective for deepening the understanding of coal and gas outburst mechanism,laying a theoretical foundation for the innovation of outburst prevention and control technologies.
文摘A new algorithm is proposed to solve the problems of shape-finding of suspension bridge with spatial cables what include tedious iteration,slow convergence speed and even no convergent under some circumstances.In this paper,the stress analysis of the main cable is carried out,and the relationship between the slope change and the coordinate change is found.This paper also discussed how to find the minimum slope point of symmetrical or asymmetric main cable,and the deformation compatibility equation is established and solved to obtain the shape of main cable.The algorithm in this paper can ensure the convergence of the solution for the suspension bridge with spatial cables.The calculation accuracy is high through the demonstration of the calculation examples.
基金the support of the National Natural Science Foundation of China(Nos.41974073,41404053)the Macao Foundation and the pre-research project of Civil Aerospace Technologies(Nos.D020308 and D020303)+2 种基金funded by the National Space Administration of Chinathe opening fund of the State Key Laboratory of Lunar and Planetary Sciences(Macao University of Science and Technology,Macao Science and Technology Development Fund No.119/2017/A3)the Specialized Research Fund for State Key Laboratories,and the NUIST-UoR International Research Institute。
文摘We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese continent.To improve the precision of the model,we considered the data gap between the ground and satellite data.We compared and analyzed the results of the Taylor polynomial,surface Spline,and CHAOS-6(the CHAMP,?rsted and SAC-C model of Earth’s magnetic field)gradient models.Results showed that the gradients in the south-north and east-west directions of the four models were consistent.The 3DSS model was able to express not only gradients at different altitudes,but also average gradients inside the research area.The two Spline models were able to capture more information on gradient anomalies than were the fitted models.Strong local anomalies were observed in northern Xinjiang,Beijing,and the junction area between Jiangsu and Zhejiang,and the total intensity F decreased whereas the altitude increased.The gradient decreased by 21.69%in the south-north direction and increased by 11.78%in the east-west direction.In addition,the altitude gradient turned from negative to positive while the altitude increased.The Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory.
基金supported by the National Natural Science Foundation of China(41977258)the National Key Research and Development Program of China(2017YFC1501005 and 2018YFC1504704)。
文摘Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.
基金supported by the Key Research and Development Program of Hebei Province[20326333D]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2019]001]Science and Technology Promotion Demonstration Project of forestry and grassland in Hebei Province[Hebei TG[2020]013]。
文摘Larix gmelinii var.principis-rupprechtii(Mayr.)Pilger is an important native tree species in North China with advantages of fast growth,straight trunk,and good wood properties.The multi-year and multi-site breeding research of families of the species has not been reported previously.Based on diameter at breast height(DBH),height and volume of 25 families on four experimental sites,we calculated variance components,genetic parameters,juvenile and mature trait correlations and made genotype main effect plus genotype×environment interaction effect(GGE)biplot based on the breeding values estimated using the method of best linear unbiased prediction(BLUP).Compared with height,DBH and volume had higher heritability and larger variation coefficients,making them the more suitable traits for family selection and evaluation.Based on these,GGE biplots containing 20 combinations of site×age were drawn using data at 13 to 17 years when the interactions between family and location were strong.Test sites classifications based on DBH,and volume were inconsistent,with two categories for DBH and one for volume.The Guyuan site was the most suitable with strong discriminating ability,high representativeness and stability among tree ages.Integrating the ranking results of DBH and volume,families 66,76,82 and 111 were high-yielding and stable,families 78 and96 were high-yielding with above average stability,families72 and 79 were high-yielding with below average stability,whereas stability of family 100 was inconsistent between DBH and volume.Early selection based on DBH was convenient and reliable,and can be made at seven years.This study provides support for the selection of Larix gmelinii var.principis-rupprechtii families in Hebei province and an example for the application of stem analysis data from multiple sites in tree breeding.
文摘Left main coronary compression syndrome(LMCS)may complicate pulmonary artery aneurysms(PAA),usually developed in the context of pulmonary arterial hypertension(PAH).We report the case of a 51-year-old female patient with an atrial septal defect(unsuitable for device closure)complicated by a PAA generating a 90%left main stenosis.The significant PAH held us back from immediate surgery.After specific dual PAH-targeted therapy(sildenafil and bosentan),the atrial septal defect could be closed with a unidirectional valved patch;the PAAinduced LMCS was treated by reductive arterioplasty.The postoperative course was uneventful.Follow-up showed clinical improvement,but PAH treatment was still needed.After three months,coronary angiography showed only an insignificant residual left main stenosis,proving that reductive pulmonary arterioplasty was effective in treating LMCS.Any PAA requires further evaluation for LMCS,a dangerous but treatable complication.The“treat-repair-treat”strategy and shunt-closure with a unidirectional valved patch can both improve surgical prospects of LMCS with shunt-related PAH.