Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstra...Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.展开更多
The writer aims at emphasizing the significance of assuring the all-round quality in Xinjiang Medical University by analyzing the current situation and problems in XMU and discussing the feasibility of the issues by p...The writer aims at emphasizing the significance of assuring the all-round quality in Xinjiang Medical University by analyzing the current situation and problems in XMU and discussing the feasibility of the issues by providing various measures and by using different managing approaches.展开更多
Quality assurance(QA)has been introduced and developed into Vietnam for almost 15 years.The importation of such a concept from other countries with different cultures may result in resistance in some ways.This study e...Quality assurance(QA)has been introduced and developed into Vietnam for almost 15 years.The importation of such a concept from other countries with different cultures may result in resistance in some ways.This study explores QA arrangements at three institutions of higher education(HE)in Vietnam,a Confucian heritage country,as perceived by academic leaders,QA practitioners,and academics to respond to QA policies from the government.The methodological approach taken in this research is a multiple case study.A qualitative approach was used to explore QA practices at three institutions.Data collected from documentation and in-depth interviews were analyzed for patterns and themes.It was found that centralism and large power distance of a Confucian collectivist country such as Vietnam significantly influenced the government’s attempts to reform HE for quality improvement.Culturally appropriate measures from the bottom level with long-term strategies should be considered to assure and improve quality,including the shift to decentralization in HE.展开更多
The Santos Basin in Brazil has witnessed significant oil and gas discoveries in deepwater pre-salt since the 21^(st)century.Currently,the waters in eastern Brazil stand out as a hot area of deepwater exploration and p...The Santos Basin in Brazil has witnessed significant oil and gas discoveries in deepwater pre-salt since the 21^(st)century.Currently,the waters in eastern Brazil stand out as a hot area of deepwater exploration and production worldwide.Based on a review of the petroleum exploration and production history in Brazil,the challenges,researches and practices,strategic transformation,significant breakthroughs,and key theories and technologies for exploration from onshore to offshore and from shallow waters to deep-ultra-deep waters and then to pre-salt strata are systematically elaborated.Within 15 years since its establishment in 1953,Petrobras explored onshore Paleozoic cratonic and marginal rift basins,and obtained some small to medium petroleum discoveries in fault-block traps.In the 1970s,Petrobras developed seismic exploration technologies and several hydrocarbon accumulation models,for example,turbidite sandstones,allowing important discoveries in shallow waters,e.g.the Namorado Field and Enchova fields.Guided by these models/technologies,significant discoveries,e.g.the Marlim and Roncador fields,were made in deepwater post-salt in the Campos Basin.In the early 21^(st)century,the advancements in theories and technologies for pre-salt petroleum system,carbonate reservoirs,hydrocarbon accumulation and nuclear magnetic resonance(NMR)logging stimulated a succession of valuable discoveries in the Lower Cretaceous lacustrine carbonates in the Santos Basin,including the world-class ultra-deepwater super giant fields such as Tupi(Lula),Mero and Buzios.Petroleum development in complex deep water environments is extremely challenging.By establishing the Technological Capacitation Program in Deep Waters(PROCAP),Petrobras developed and implemented key technologies including managed pressure drilling(MPD)with narrow pressure window,pressurized mud cap drilling(PMCD),multi-stage intelligent completion,development with Floating Production Storage and Offloading units(FPSO),and flow assurance,which remarkably improved the drilling,completion,field development and transportation efficiency and safety.Additionally,under the limited FPSO capacity,Petrobras promoted the world-largest CCUS-EOR project,which contributed effectively to the reduction of greenhouse gas emissions and the enhancement of oil recovery.Development and application of these technologies provide valuable reference for deep and ultra-deepwater petroleum exploration and production worldwide.The petroleum exploration in Brazil will consistently focus on ultra-deep water pre-salt carbonates and post-salt turbidites,and seek new opportunities in Paleozoic gas.Technical innovation and strategic cooperation will be held to promote the sustainable development of Brazil's oil and gas industry.展开更多
As big data becomes an apparent challenge to handle when building a business intelligence(BI)system,there is a motivation to handle this challenging issue in higher education institutions(HEIs).Monitoring quality in H...As big data becomes an apparent challenge to handle when building a business intelligence(BI)system,there is a motivation to handle this challenging issue in higher education institutions(HEIs).Monitoring quality in HEIs encompasses handling huge amounts of data coming from different sources.This paper reviews big data and analyses the cases from the literature regarding quality assurance(QA)in HEIs.It also outlines a framework that can address the big data challenge in HEIs to handle QA monitoring using BI dashboards and a prototype dashboard is presented in this paper.The dashboard was developed using a utilisation tool to monitor QA in HEIs to provide visual representations of big data.The prototype dashboard enables stakeholders to monitor compliance with QA standards while addressing the big data challenge associated with the substantial volume of data managed by HEIs’QA systems.This paper also outlines how the developed system integrates big data from social media into the monitoring dashboard.展开更多
A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress the...A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress theory(MCST).The material properties are assumed to follow a power-law distribution along the chordwise direction.The model introduces one axial stretching variable and four transverse deflection variables including two pure bending components and two pure shear ones.The complex modal analysis and assumed mode methods are used to solve the governing equations of motion under different boundary conditions(BCs).Several examples are presented to verify the effectiveness of the developed model.By coupling the slenderness ratio,gradient index,rotation speed,and size effect with the pre-twisted angle,the effects of these factors on the thermomechanical vibration of the microbeam with different BCs are investigated.It is found that with the increase in the pre-twisted angle,the critical slenderness ratio and gradient index corresponding to the thermal instability of the microbeam increase,while the critical material length scale parameter(MLSP)and rotation speed decrease.The sensitivity of the fundamental frequency to temperature increases with the increasing slenderness ratio and gradient index,and decreases with the other increasing parameters.Moreover,the size effect can suppress the dynamic stiffening effect and enhance the Coriolis effect.Finally,the mode transition is quantitatively demonstrated by a modal assurance criterion(MAC).展开更多
This paper draws on the experience of the eighth plenary meeting of the ISO/TC 321, Transaction assurance in e-commerce, held in Hangzhou of China in November 2023, and explores potential ways in which developing coun...This paper draws on the experience of the eighth plenary meeting of the ISO/TC 321, Transaction assurance in e-commerce, held in Hangzhou of China in November 2023, and explores potential ways in which developing countries in Africa can drive their development and contribute to global industrial progress by leveraging ISO/TC 321 standards. It provides practical recommendations for utilizing e-commerce standardization and related standards to stimulate economic growth and enhance business practices.展开更多
Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality thr...Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance.Current quality control(QC)and quality assurance(QA)plans provide limited coverage.Consequently,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation methods.It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics.The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality.The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint.The paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during construction.It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.展开更多
Information security and quality management are often considered two different fields. However, organizations must be mindful of how software security may affect quality control. This paper examines and promotes metho...Information security and quality management are often considered two different fields. However, organizations must be mindful of how software security may affect quality control. This paper examines and promotes methods through which secure software development processes can be integrated into the Systems Software Development Life-cycle (SDLC) to improve system quality. Cyber-security and quality assurance are both involved in reducing risk. Software security teams work to reduce security risks, whereas quality assurance teams work to decrease risks to quality. There is a need for clear standards, frameworks, processes, and procedures to be followed by organizations to ensure high-level quality while reducing security risks. This research uses a survey of industry professionals to help identify best practices for developing software with fewer defects from the early stages of the SDLC to improve both the quality and security of software. Results show that there is a need for better security awareness among all members of software development teams.展开更多
Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process...Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.展开更多
With the petroleum industry endeavoring to develop promising oil and gas in deeper water, gas hydrates prevention is a serious concern for oil and gas producing companies producing at conditions in the hydrate region....With the petroleum industry endeavoring to develop promising oil and gas in deeper water, gas hydrates prevention is a serious concern for oil and gas producing companies producing at conditions in the hydrate region. This paper details lessons learned from the successful field deployment of AA LDHI and proper implementation strategies used for 3 different practical fields as case studies in the Gulf of Mexico. From the 3 field experiences, the AA LDHI has been used to replace the conventional thermodynamic hydrate inhibitor due to its numerous benefits during steady state operations and transition operations where AA LDHI is injected prior to extended shut in and restart for fields producing at low water cut. However, the strategy to develop a cost effective chemical management of hydrates for fields producing at high water cut is by pumping methanol or diesel to push down the wellbore fluid below the mud line during planned and unplanned shut-ins to delay water production, it also secures the riser with non hydrate fluids. This illustrates how the AA LDHIs are used in conjunction with more conventional hydrate management approaches to reach an optimal cost effective field hydrate management solution. However, this shows that the key to overall success of hydrate prevention is a full integration of a good front end design, a comprehensive deployment and an effective down hole monitoring system.展开更多
Estimating the oil-water temperatures in flowlines is challenging especially in deepwater and ultra-deepwater offshore applications where issues of flow assurance and dramatic heat transfer are likely to occur due to ...Estimating the oil-water temperatures in flowlines is challenging especially in deepwater and ultra-deepwater offshore applications where issues of flow assurance and dramatic heat transfer are likely to occur due to the temperature difference between the fluids and the surroundings. Heat transfer analysis is very important for the prediction and prevention of deposits in oil and water flowlines, which could impede the flow and give rise to huge financial losses. Therefore, a 3D mathematical model of oil-water Newtonian flow under non-isothermal conditions is established to explore the complex mechanisms of the two-phase oil-water transportation and heat transfer in different flowline inclinations. In this work, a non-isothermal two-phase flow model is first modified and then implemented in the InterFoam solver by introducing the energy equation using OpenFOAM® code. The Low Reynolds Number (LRN) k-ε turbulence model is utilized to resolve the turbulence phenomena within the oil and water mixtures. The flow patterns and the local heat transfer coefficients (HTC) for two-phase oil-water flow at different flowlines inclinations (0°, +4°, +7°) are validated by the experimental literature results and the relative errors are also compared. Global sensitivity analysis is then conducted to determine the effect of the different parameters on the performance of the produced two-phase hydrocarbon systems for effective subsea fluid transportation. Thereafter, HTC and flow patterns for oil-water flows at downward inclinations of 4°, and 7° can be predicted by the models. The velocity distribution, pressure gradient, liquid holdup, and temperature variation at the flowline cross-sections are simulated and analyzed in detail. Consequently, the numerical model can be generally applied to compute the global properties of the fluid and other operating parameters that are beneficial in the management of two-phase oil-water transportation.展开更多
Continuously improving the internal quality assurance system and promoting the innovative development of higher vocational education is a challenge that every higher vocational institution must solve on the road of di...Continuously improving the internal quality assurance system and promoting the innovative development of higher vocational education is a challenge that every higher vocational institution must solve on the road of diagnosis and improvement.To address the current dilemma of building internal quality assurance systems in higher education institutions,this study utilizes a case study approach.This study takes Jingzhou Vocational and Technical College as the research object for research.Conclusion:The excellent diagnosis and reform model and the effectiveness of diagnosis and reform in this school can provide new strategic ideas for the practice of diagnosis and reform for the high-quality development of higher education in Hubei.展开更多
The capability of a system to fulfill its mission promptly in the presence of attacks,failures,or accidents is one of the qualitative definitions of survivability.In this paper,we propose a model for survivability qua...The capability of a system to fulfill its mission promptly in the presence of attacks,failures,or accidents is one of the qualitative definitions of survivability.In this paper,we propose a model for survivability quantification,which is acceptable for networks carrying complex traffic flows.Complex network traffic is considered as general multi-rate,heterogeneous traffic,where the individual bandwidth demands may aggregate in complex,nonlinear ways.Blocking probability is the chosen measure for survivability analysis.We study an arbitrary topology and some other known topologies for the network.Independent and dependent failure scenarios as well as deterministic and random traffic models are investigated.Finally,we provide survivability evaluation results for different network configurations.The results show that by using about 50%of the link capacity in networks with a relatively high number of links,the blocking probability remains near zero in the case of a limited number of failures.展开更多
Since each rock joint is unique by nature,the utilization of replicas in direct shear testing is required to carry out experimental parameter studies.However,information about the ability of the replicas to simulate t...Since each rock joint is unique by nature,the utilization of replicas in direct shear testing is required to carry out experimental parameter studies.However,information about the ability of the replicas to simulate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking.With the aim to facilitate generation of high-quality direct shear test data from replicas,a novel component in the testing procedure is introduced by presenting two parameters for geometric quality assurance.The parameters are derived from surface comparisons of three-dimensional(3D)scanning data of the rock joint and its replicas.The first parameter,smf,captures morphological deviations between the replica and the rock joint surfaces.smf is derived as the standard deviation of the deviations between the coordinate points of the replica and the rock joint.Four sources of errors introduced in the replica manufacturing process employed in this study could be identified.These errors could be minimized,yielding replicas with smf0.06 mm.The second parameter is a vector,VHp100,which describes deviations with respect to the shear direction.It is the projection of the 100 mm long normal vector of the best-fit plane of the replica joint surface to the corresponding plane of the rock joint.VHp100was found to be less than or equal to 0.36 mm in this study.Application of these two geometric quality assurance parameters demonstrates that it is possible to manufacture replicas with high geometric similarity to the rock joint.In a subsequent paper(part 2),smf and VHp100 are incorporated in a novel quality assurance method,in which the parameters shall be evaluated prior to direct shear testing.Replicas having parameter values below established thresholds shall have a known and narrow dispersion and imitate the shear mechanical behavior of the rock joint.展开更多
The main aim of future mobile networks is to provide secure,reliable,intelligent,and seamless connectivity.It also enables mobile network operators to ensure their customer’s a better quality of service(QoS).Nowadays...The main aim of future mobile networks is to provide secure,reliable,intelligent,and seamless connectivity.It also enables mobile network operators to ensure their customer’s a better quality of service(QoS).Nowadays,Unmanned Aerial Vehicles(UAVs)are a significant part of the mobile network due to their continuously growing use in various applications.For better coverage,cost-effective,and seamless service connectivity and provisioning,UAVs have emerged as the best choice for telco operators.UAVs can be used as flying base stations,edge servers,and relay nodes in mobile networks.On the other side,Multi-access EdgeComputing(MEC)technology also emerged in the 5G network to provide a better quality of experience(QoE)to users with different QoS requirements.However,UAVs in a mobile network for coverage enhancement and better QoS face several challenges such as trajectory designing,path planning,optimization,QoS assurance,mobilitymanagement,etc.The efficient and proactive path planning and optimization in a highly dynamic environment containing buildings and obstacles are challenging.So,an automated Artificial Intelligence(AI)enabled QoSaware solution is needed for trajectory planning and optimization.Therefore,this work introduces a well-designed AI and MEC-enabled architecture for a UAVs-assisted future network.It has an efficient Deep Reinforcement Learning(DRL)algorithm for real-time and proactive trajectory planning and optimization.It also fulfills QoS-aware service provisioning.A greedypolicy approach is used to maximize the long-term reward for serving more users withQoS.Simulation results reveal the superiority of the proposed DRL mechanism for energy-efficient and QoS-aware trajectory planning over the existing models.展开更多
文摘Introduction: The ring vortex phantom is a novel, cost-effective prototype which generates complex and well-characterised reference flows in the form of the ring vortex. Although its reproducibility has been demonstrated, with ring speeds routinely behaving within 10% tolerances at speeds of approximately 10 - 70 cm/s, a form of real-time QA of the device at the time of imaging is needed to confirm correct function on demand in any environment. Methods: The technology described here achieves real-time QA, comprising a linear encoder, laser-photodiode array, and Doppler probe, measuring piston motion, ring speed and intra-ring velocity respectively. This instrumentation does not interfere with imaging system QA, but allows QA to be performed on both the ring vortex and the device in real-time. Results: The encoder reports the reliability of the piston velocity profile, whilst ring speed is measured by laser behaviour. Incorporation of a calibrated Doppler probe offers a consistency check that confirms behaviour of the central axial flow. For purposes of gold-standard measurement, all elements can be related to previous Laser PIV acquisitions with the same device settings. Conclusion: Consequently, ring vortex production within tolerances is confirmed by this instrumentation, delivering accurate QA in real-time. This implementation offers a phantom QA procedure that exceeds anything seen in the literature, providing the technology to enhance quantitative assessment of flow imaging modalities.
文摘The writer aims at emphasizing the significance of assuring the all-round quality in Xinjiang Medical University by analyzing the current situation and problems in XMU and discussing the feasibility of the issues by providing various measures and by using different managing approaches.
文摘Quality assurance(QA)has been introduced and developed into Vietnam for almost 15 years.The importation of such a concept from other countries with different cultures may result in resistance in some ways.This study explores QA arrangements at three institutions of higher education(HE)in Vietnam,a Confucian heritage country,as perceived by academic leaders,QA practitioners,and academics to respond to QA policies from the government.The methodological approach taken in this research is a multiple case study.A qualitative approach was used to explore QA practices at three institutions.Data collected from documentation and in-depth interviews were analyzed for patterns and themes.It was found that centralism and large power distance of a Confucian collectivist country such as Vietnam significantly influenced the government’s attempts to reform HE for quality improvement.Culturally appropriate measures from the bottom level with long-term strategies should be considered to assure and improve quality,including the shift to decentralization in HE.
文摘The Santos Basin in Brazil has witnessed significant oil and gas discoveries in deepwater pre-salt since the 21^(st)century.Currently,the waters in eastern Brazil stand out as a hot area of deepwater exploration and production worldwide.Based on a review of the petroleum exploration and production history in Brazil,the challenges,researches and practices,strategic transformation,significant breakthroughs,and key theories and technologies for exploration from onshore to offshore and from shallow waters to deep-ultra-deep waters and then to pre-salt strata are systematically elaborated.Within 15 years since its establishment in 1953,Petrobras explored onshore Paleozoic cratonic and marginal rift basins,and obtained some small to medium petroleum discoveries in fault-block traps.In the 1970s,Petrobras developed seismic exploration technologies and several hydrocarbon accumulation models,for example,turbidite sandstones,allowing important discoveries in shallow waters,e.g.the Namorado Field and Enchova fields.Guided by these models/technologies,significant discoveries,e.g.the Marlim and Roncador fields,were made in deepwater post-salt in the Campos Basin.In the early 21^(st)century,the advancements in theories and technologies for pre-salt petroleum system,carbonate reservoirs,hydrocarbon accumulation and nuclear magnetic resonance(NMR)logging stimulated a succession of valuable discoveries in the Lower Cretaceous lacustrine carbonates in the Santos Basin,including the world-class ultra-deepwater super giant fields such as Tupi(Lula),Mero and Buzios.Petroleum development in complex deep water environments is extremely challenging.By establishing the Technological Capacitation Program in Deep Waters(PROCAP),Petrobras developed and implemented key technologies including managed pressure drilling(MPD)with narrow pressure window,pressurized mud cap drilling(PMCD),multi-stage intelligent completion,development with Floating Production Storage and Offloading units(FPSO),and flow assurance,which remarkably improved the drilling,completion,field development and transportation efficiency and safety.Additionally,under the limited FPSO capacity,Petrobras promoted the world-largest CCUS-EOR project,which contributed effectively to the reduction of greenhouse gas emissions and the enhancement of oil recovery.Development and application of these technologies provide valuable reference for deep and ultra-deepwater petroleum exploration and production worldwide.The petroleum exploration in Brazil will consistently focus on ultra-deep water pre-salt carbonates and post-salt turbidites,and seek new opportunities in Paleozoic gas.Technical innovation and strategic cooperation will be held to promote the sustainable development of Brazil's oil and gas industry.
文摘As big data becomes an apparent challenge to handle when building a business intelligence(BI)system,there is a motivation to handle this challenging issue in higher education institutions(HEIs).Monitoring quality in HEIs encompasses handling huge amounts of data coming from different sources.This paper reviews big data and analyses the cases from the literature regarding quality assurance(QA)in HEIs.It also outlines a framework that can address the big data challenge in HEIs to handle QA monitoring using BI dashboards and a prototype dashboard is presented in this paper.The dashboard was developed using a utilisation tool to monitor QA in HEIs to provide visual representations of big data.The prototype dashboard enables stakeholders to monitor compliance with QA standards while addressing the big data challenge associated with the substantial volume of data managed by HEIs’QA systems.This paper also outlines how the developed system integrates big data from social media into the monitoring dashboard.
基金the National Natural Science Foundation of China(Nos.11602204 and 12102373)the Fundamental Research Funds for the Central Universities of China(Nos.2682022ZTPY081 and 2682022CX056)the Natural Science Foundation of Sichuan Province of China(Nos.2023NSFSC0849,2023NSFSC1300,2022NSFSC1938,and 2022NSFSC2003)。
文摘A three-dimensional(3D)thermomechanical vibration model is developed for rotating pre-twisted functionally graded(FG)microbeams according to the refined shear deformation theory(RSDT)and the modified couple stress theory(MCST).The material properties are assumed to follow a power-law distribution along the chordwise direction.The model introduces one axial stretching variable and four transverse deflection variables including two pure bending components and two pure shear ones.The complex modal analysis and assumed mode methods are used to solve the governing equations of motion under different boundary conditions(BCs).Several examples are presented to verify the effectiveness of the developed model.By coupling the slenderness ratio,gradient index,rotation speed,and size effect with the pre-twisted angle,the effects of these factors on the thermomechanical vibration of the microbeam with different BCs are investigated.It is found that with the increase in the pre-twisted angle,the critical slenderness ratio and gradient index corresponding to the thermal instability of the microbeam increase,while the critical material length scale parameter(MLSP)and rotation speed decrease.The sensitivity of the fundamental frequency to temperature increases with the increasing slenderness ratio and gradient index,and decreases with the other increasing parameters.Moreover,the size effect can suppress the dynamic stiffening effect and enhance the Coriolis effect.Finally,the mode transition is quantitatively demonstrated by a modal assurance criterion(MAC).
文摘This paper draws on the experience of the eighth plenary meeting of the ISO/TC 321, Transaction assurance in e-commerce, held in Hangzhou of China in November 2023, and explores potential ways in which developing countries in Africa can drive their development and contribute to global industrial progress by leveraging ISO/TC 321 standards. It provides practical recommendations for utilizing e-commerce standardization and related standards to stimulate economic growth and enhance business practices.
文摘Longitudinal joint construction quality is critical to the life of flexible pavements.Maintaining deteriorated longitudinal joints has become a challenge for many highway agencies.Improving the joint's quality through better compaction during construction can help achieve flexible pavements with longer service lives and less maintenance.Current quality control(QC)and quality assurance(QA)plans provide limited coverage.Consequently,the risk of missing areas with poor joint compaction is significant.A density profiling system(DPS)is a non-destructive alternative to conventional destructive evaluation methods.It can provide quick and continuous real-time coverage of the compaction during construction in dielectrics.The paper presents several case studies comparing various types of longitudinal joints and demonstrating the use of DPS to evaluate the joint's compaction quality.The paper shows that dielectric measurements can provide valuable insight into the ability of various construction techniques to achieve adequate levels of compaction at the longitudinal joint.The paper proposes a dielectric-based longitudinal joint quality index(LJQI)to evaluate the relative compaction of the joint during construction.It also shows that adopting DPS for assessing the compaction of longitudinal joints can minimize the risk of agencies accepting poorly constructed joints,identify locations of poor quality during construction,and achieve better-performing flexible pavements.
文摘Information security and quality management are often considered two different fields. However, organizations must be mindful of how software security may affect quality control. This paper examines and promotes methods through which secure software development processes can be integrated into the Systems Software Development Life-cycle (SDLC) to improve system quality. Cyber-security and quality assurance are both involved in reducing risk. Software security teams work to reduce security risks, whereas quality assurance teams work to decrease risks to quality. There is a need for clear standards, frameworks, processes, and procedures to be followed by organizations to ensure high-level quality while reducing security risks. This research uses a survey of industry professionals to help identify best practices for developing software with fewer defects from the early stages of the SDLC to improve both the quality and security of software. Results show that there is a need for better security awareness among all members of software development teams.
文摘Based on the analysis of the development process system status of domestic and foreign civil aircraft airborne system suppliers,this paper proposes the overall construction idea of"a set of civil aircraft process system"based on IPD(Integrated product development)in the organization.The development stage,process,activity and task are the logical framework elements of the system construction."Based on process decomposition,vertical stratification,horizontal segmentation,combination of special and common,process customized to tools,role and process integration,giving full consideration to the interface between supplier management and process modules"etc.are the concrete ideas.Moreover,formulate top⁃level system construction standards,implemented by process system management tool platform,so that the process system and development work can be effectively integrated to effectively guide the development work of airborne system suppliers,and meet the quality and airworthiness requirements of civil aircraft development.Through the development application of a certain type of flight control system,the process system and tool platform were verified and optimized in practice.
文摘With the petroleum industry endeavoring to develop promising oil and gas in deeper water, gas hydrates prevention is a serious concern for oil and gas producing companies producing at conditions in the hydrate region. This paper details lessons learned from the successful field deployment of AA LDHI and proper implementation strategies used for 3 different practical fields as case studies in the Gulf of Mexico. From the 3 field experiences, the AA LDHI has been used to replace the conventional thermodynamic hydrate inhibitor due to its numerous benefits during steady state operations and transition operations where AA LDHI is injected prior to extended shut in and restart for fields producing at low water cut. However, the strategy to develop a cost effective chemical management of hydrates for fields producing at high water cut is by pumping methanol or diesel to push down the wellbore fluid below the mud line during planned and unplanned shut-ins to delay water production, it also secures the riser with non hydrate fluids. This illustrates how the AA LDHIs are used in conjunction with more conventional hydrate management approaches to reach an optimal cost effective field hydrate management solution. However, this shows that the key to overall success of hydrate prevention is a full integration of a good front end design, a comprehensive deployment and an effective down hole monitoring system.
文摘Estimating the oil-water temperatures in flowlines is challenging especially in deepwater and ultra-deepwater offshore applications where issues of flow assurance and dramatic heat transfer are likely to occur due to the temperature difference between the fluids and the surroundings. Heat transfer analysis is very important for the prediction and prevention of deposits in oil and water flowlines, which could impede the flow and give rise to huge financial losses. Therefore, a 3D mathematical model of oil-water Newtonian flow under non-isothermal conditions is established to explore the complex mechanisms of the two-phase oil-water transportation and heat transfer in different flowline inclinations. In this work, a non-isothermal two-phase flow model is first modified and then implemented in the InterFoam solver by introducing the energy equation using OpenFOAM® code. The Low Reynolds Number (LRN) k-ε turbulence model is utilized to resolve the turbulence phenomena within the oil and water mixtures. The flow patterns and the local heat transfer coefficients (HTC) for two-phase oil-water flow at different flowlines inclinations (0°, +4°, +7°) are validated by the experimental literature results and the relative errors are also compared. Global sensitivity analysis is then conducted to determine the effect of the different parameters on the performance of the produced two-phase hydrocarbon systems for effective subsea fluid transportation. Thereafter, HTC and flow patterns for oil-water flows at downward inclinations of 4°, and 7° can be predicted by the models. The velocity distribution, pressure gradient, liquid holdup, and temperature variation at the flowline cross-sections are simulated and analyzed in detail. Consequently, the numerical model can be generally applied to compute the global properties of the fluid and other operating parameters that are beneficial in the management of two-phase oil-water transportation.
文摘Continuously improving the internal quality assurance system and promoting the innovative development of higher vocational education is a challenge that every higher vocational institution must solve on the road of diagnosis and improvement.To address the current dilemma of building internal quality assurance systems in higher education institutions,this study utilizes a case study approach.This study takes Jingzhou Vocational and Technical College as the research object for research.Conclusion:The excellent diagnosis and reform model and the effectiveness of diagnosis and reform in this school can provide new strategic ideas for the practice of diagnosis and reform for the high-quality development of higher education in Hubei.
文摘The capability of a system to fulfill its mission promptly in the presence of attacks,failures,or accidents is one of the qualitative definitions of survivability.In this paper,we propose a model for survivability quantification,which is acceptable for networks carrying complex traffic flows.Complex network traffic is considered as general multi-rate,heterogeneous traffic,where the individual bandwidth demands may aggregate in complex,nonlinear ways.Blocking probability is the chosen measure for survivability analysis.We study an arbitrary topology and some other known topologies for the network.Independent and dependent failure scenarios as well as deterministic and random traffic models are investigated.Finally,we provide survivability evaluation results for different network configurations.The results show that by using about 50%of the link capacity in networks with a relatively high number of links,the blocking probability remains near zero in the case of a limited number of failures.
文摘Since each rock joint is unique by nature,the utilization of replicas in direct shear testing is required to carry out experimental parameter studies.However,information about the ability of the replicas to simulate the shear mechanical behavior of the rock joint and their dispersion in direct shear testing is lacking.With the aim to facilitate generation of high-quality direct shear test data from replicas,a novel component in the testing procedure is introduced by presenting two parameters for geometric quality assurance.The parameters are derived from surface comparisons of three-dimensional(3D)scanning data of the rock joint and its replicas.The first parameter,smf,captures morphological deviations between the replica and the rock joint surfaces.smf is derived as the standard deviation of the deviations between the coordinate points of the replica and the rock joint.Four sources of errors introduced in the replica manufacturing process employed in this study could be identified.These errors could be minimized,yielding replicas with smf0.06 mm.The second parameter is a vector,VHp100,which describes deviations with respect to the shear direction.It is the projection of the 100 mm long normal vector of the best-fit plane of the replica joint surface to the corresponding plane of the rock joint.VHp100was found to be less than or equal to 0.36 mm in this study.Application of these two geometric quality assurance parameters demonstrates that it is possible to manufacture replicas with high geometric similarity to the rock joint.In a subsequent paper(part 2),smf and VHp100 are incorporated in a novel quality assurance method,in which the parameters shall be evaluated prior to direct shear testing.Replicas having parameter values below established thresholds shall have a known and narrow dispersion and imitate the shear mechanical behavior of the rock joint.
基金This work was supported by the Fundamental Research Funds for the Central Universities(No.2019XD-A07)the Director Fund of Beijing Key Laboratory of Space-ground Interconnection and Convergencethe National Key Laboratory of Science and Technology on Vacuum Electronics.
文摘The main aim of future mobile networks is to provide secure,reliable,intelligent,and seamless connectivity.It also enables mobile network operators to ensure their customer’s a better quality of service(QoS).Nowadays,Unmanned Aerial Vehicles(UAVs)are a significant part of the mobile network due to their continuously growing use in various applications.For better coverage,cost-effective,and seamless service connectivity and provisioning,UAVs have emerged as the best choice for telco operators.UAVs can be used as flying base stations,edge servers,and relay nodes in mobile networks.On the other side,Multi-access EdgeComputing(MEC)technology also emerged in the 5G network to provide a better quality of experience(QoE)to users with different QoS requirements.However,UAVs in a mobile network for coverage enhancement and better QoS face several challenges such as trajectory designing,path planning,optimization,QoS assurance,mobilitymanagement,etc.The efficient and proactive path planning and optimization in a highly dynamic environment containing buildings and obstacles are challenging.So,an automated Artificial Intelligence(AI)enabled QoSaware solution is needed for trajectory planning and optimization.Therefore,this work introduces a well-designed AI and MEC-enabled architecture for a UAVs-assisted future network.It has an efficient Deep Reinforcement Learning(DRL)algorithm for real-time and proactive trajectory planning and optimization.It also fulfills QoS-aware service provisioning.A greedypolicy approach is used to maximize the long-term reward for serving more users withQoS.Simulation results reveal the superiority of the proposed DRL mechanism for energy-efficient and QoS-aware trajectory planning over the existing models.