Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of exp...Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of expertise required and the potential risks involved,it is crucial to emphasize safety management during construction.This paper delves into the significance of construction safety management for electromechanical installation projects,identifies common problems encountered during construction,and proposes solutions.This analysis aims to provide relevant personnel with essential guidance and references for managing electromechanical installation projects safely.展开更多
Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test b...Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer functions.It is important,however,to allow for installation effects due to shielding by fairings or the train body.In the current work,fast-running analytical models are developed to determine these installation effects.The model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier model.For equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s functions.The bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field approach.The sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s functions.Results show good agreement with a 2.5D boundary element model and with measurements.Modelling uncertainty and parametric uncertainty are evaluated.The largest variability occurs due to the height and impedance of the ground,especially for a low receiver.This leads to standard deviations of up to 4 dB at low frequencies.For the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.展开更多
Translation of specialized documents in optometry presents unique challenges,requiring a deep understanding of the professional context,terminology,and adherence to specific translation styles.This paper delves into t...Translation of specialized documents in optometry presents unique challenges,requiring a deep understanding of the professional context,terminology,and adherence to specific translation styles.This paper delves into the translation theory and techniques employed in the English-to-Chinese translation of the“Optoform 80 Installation and Maintenance Manual”,serving as a case study.Emphasizing Nida’s theory of functional equivalence,the paper explores the complexities of translating professional optometry literature,focusing on key points and common issues in translating installation and maintenance manuals for optometric devices.Special attention is given to the translation of professional terminology,employing methods such as addition,omission,conversion,and repetition.The translation process aims to meet specific requirements,ensuring accuracy and coherence while aligning with Chinese language conventions.The paper also analyzes translation methods and techniques concerning terminology,prepositions,conjunctions,and handling parallel elements based on practical insights from the Optoform 80 Manual.展开更多
To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction tec...To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction technology.These aspects include the lightning protection classification of buildings,air terminals,down conductors,grounding devices,division of lightning protection zones,and lightning electromagnetic pulse shielding.Through the introduction of this article,readers can gain a comprehensive understanding of the application and value of lightning protection grounding construction technology in building electrical installation projects.展开更多
Compliant vertical access risers(CVAR)have broad application prospects in deep-water oil and gas transportation.However,the mechanical behaviors of the CVAR with a variable length during installation remains unclear.T...Compliant vertical access risers(CVAR)have broad application prospects in deep-water oil and gas transportation.However,the mechanical behaviors of the CVAR with a variable length during installation remains unclear.To address this issue,based on the flexible segment method,a model of CVAR with a variable length during installation is established in this study,which is verified by the comparison with commercial software.Then,the mechanical behaviors of CVAR during installation are investigated.The results reveal that the CVAR configuration is significantly affected by the buoyancy blocks.The streamwise displacement of CVAR increases with the increase of current velocity.When the BOP weight is insuffcient,obvious upbending is observed in the lower region and transition region,leading to local compression.When the platform moves in the opposite direction to the current,the maximum stress is larger than that of the scenario when the platform moves in the same direction as the current.展开更多
Suction caissons are widely used for anchoring floating platform and offshore wind turbines.Penetration of the suction caisson into the desired position under the combination of its self-weight and applied suction res...Suction caissons are widely used for anchoring floating platform and offshore wind turbines.Penetration of the suction caisson into the desired position under the combination of its self-weight and applied suction resulted from pumping out the encased water is integral to practical engineering.Model tests were carried out to investigate the suctionassisted installation of suction caissons in clay under various undrained shear strengths.It was found that there exists a critical penetration depth value.When the penetration depth is smaller than the critical value,the soil plug undrained shear strength is higher than intact clay(i.e.,clay prior to installation).However,when the penetration depth is greater than the critical penetration depth,the undrained shear strength of soil plug is lower than intact clay.The critical value decreases with the increasing consolidation time and undrained shear strength of clay.During suction-assisted installation,cracks occur around suction caissons.The installation way has little effect on the crack formation.The influence range(i.e.,the maximum distance between the crack and the suction caisson edge)was found to increase with the increasing friction coefficient of interface between the suction caisson wall and soil and decreases with the increasing soil undrained shear strength.In addition,the drained condition of the clay during installation is dominated by the caisson aspect ratio,the undrained shear strength and the friction coefficient between the caisson wall and clay.Equations to estimate the penetration resistance and the required suction to install the suction caisson are summarized.展开更多
Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we p...Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we proposed an optimum allocation method of installed capacity of the solar-thermal power station based on chance constrained programming in this work.Firstly,we established the uncertainty model of wind power and PV based on the chance constrained planning theory.Then we used the K-medoids clusteringmethod to cluster the scenarios considering the actual operation scenarios throughout the year.Secondly,we established the optimal configuration model based on the objective function of the strongest transient voltage stability and the lowest overall cost of operation.Finally,by quantitative analysis of actual wind power and photovoltaic new energy base,this work verified the feasibility of the proposed method.As a result of the simulations,we found that using the optimal configuration method of solar-thermal power stations could ensure an accurate allocation of installed capacity.When the installed capacity of the solar-thermal power station is 1×106 kW,the transient voltage recovery index(TVRI)is 0.359,which has a strong voltage support capacity for the system.Based on the results of this work,the optimal configuration of the installed capacity of the solar-thermal power plant can improve peak shaving performance,transient voltage support capability,and new energy consumption while satisfying the Direct Current(DC)outgoing transmission premise.展开更多
In 2010,the first offshore wind turbine with integrated installation was established in Qidong sea area of Jiangsu Province,China,which led to the implementation phase of one-step-installation technique based on the d...In 2010,the first offshore wind turbine with integrated installation was established in Qidong sea area of Jiangsu Province,China,which led to the implementation phase of one-step-installation technique based on the design and construction of large-scale bucket-top-bearing (LSBTB) bucket foundation.The critical technique of LSBTB bucket foundation included self-floating towing,penetration with adjustment of horizontal levelness,removability and one-step-installation.The process of one-step-installation included the prefabrication of LSBTB bucket foundation in onshore construction base,installation and debugging of wind power,overall water transportation of foundation and wind power system,and installation of foundation and offshore wind turbine on the appointed sea area.The cost of one-step-installation technique was about 5 000 Yuan/kW,which was 30%-50% lower than that of the existing technique.The prefabrication of LSBTB bucket foundation took about two months.During the one-step-installation process,the installation and debugging of wind power and overall water transportation need about one to two days in sea area within 35 m depth.After the proposed technique is industrialized,the cost will be further reduced,and the installation capacity is expected to be up to 500 wind turbines per year.展开更多
In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated...In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.展开更多
The subsea suspended manifold designed to replace the traditional foundation structure with the buoys is a new generation subsea production system that can be suspended at a certain height from the seafloor and rapidl...The subsea suspended manifold designed to replace the traditional foundation structure with the buoys is a new generation subsea production system that can be suspended at a certain height from the seafloor and rapidly recycled by its own buoyancy.Due to complex environmental conditions,its hydrodynamic performance in the splash zone is extremely important for the safety of the whole installation process.In this paper,the mathematical model for the dynamic analysis of the seawater ingress process of the single-layer pre-set horizontal cabin is proposed based on the different center of gravity positions of the buoy.Meanwhile,the theoretical analysis of fiber cable is divided into infinite differential units by the discretization method,and the formulae of the horizontal displacement of the subsea suspended manifold are presented.In addition,the simulations are carried out to verify the rules of the dynamic responses on the subsea suspended manifold system with the consideration of the environmental conditions in the South China Sea.Comparing with the calculated value of the mathematical model of the cabin water ingress,the error of the simulation result by use of FLUENT is about 5.47%.Furthermore,the wave height is greater than the current impact on the lowering manifold system and the azimuth angle of the installation vessel is aligned with the direction of the environmental load.展开更多
A new dynamically installed plate anchor, the Flying Wing Anchor~?, has been developed as a sustainable anchor concept for deep-water offshore wind turbines. The anchor is firstly installed by free-fall penetration an...A new dynamically installed plate anchor, the Flying Wing Anchor~?, has been developed as a sustainable anchor concept for deep-water offshore wind turbines. The anchor is firstly installed by free-fall penetration and then followed by drag embedment. If the anchor is subjected to environmental loads, it dives deeper to mobilize a higher capacity. This study presents a series of free-fall penetration tests with model anchors in different weights to assess the anchor behavior during the free-fall penetration performance in one-layer soil with a constant shear strength profile. Anchor velocities and embedment depths were measured by a magnetometer. An energy-based model and a force-based model were calibrated against the test results of model anchors with different weights. Based on the calibrated force-based model, a series of design charts were developed to estimate the embedment depth of anchors in different sizes and with different impact velocities in various marine clays. The framework to plot design charts presented herein can be potentially applied to other dynamically installed anchors to predict embedment depth in engineering practice.展开更多
Solar Photovoltaic (PV) can be considered as one of the most reliable and promising renewable systems. This is of great importance for developing countries like Nigeria especially in the rural communities where there ...Solar Photovoltaic (PV) can be considered as one of the most reliable and promising renewable systems. This is of great importance for developing countries like Nigeria especially in the rural communities where there is little or no access to electricity. The use of solar energy will no doubt contribute to the improvement of the living conditions of these villagers. Solar PV systems have been installed in some villages in Nigeria but unfortunately, the expected benefits from using these systems have been jeopardized. The objective of this work is to embark on performance assessments of in- stalled Solar PV system in Oke-Agunla, Akure local government of Ondo State in Nigeria. Visits were conducted to the village;equipments on ground were examined while the people were interviewed. Both functional and non-functional facilities were traced to their manufacturers using the identification data on them and rated to ensure their efficiencies. Energy demands were also prorated, and observed the need to improve on the present energy supplied. Results of the assessments shows that PV facilities used were inadequate, trained technicians were not available giving room for quacks working on the facilities occasionally resulted in further complications and poor facilities maintenance. The assessment result shows that just 14.52% of the 4.5 kW installed solar PV was utilized due to significant malfunctioning and deterioration in performance. It can be concluded from this study that the installed solar PV systems was inefficient as a result of poor maintenance, lack of technical know-how and inability of the project contractors or managers to take these factors into consideration while embarking on the solar PV installations.展开更多
文摘Various industries today rely on the support of electromechanical equipment,expanding its scope of application and leading to an increase in electromechanical installation projects.However,due to the high level of expertise required and the potential risks involved,it is crucial to emphasize safety management during construction.This paper delves into the significance of construction safety management for electromechanical installation projects,identifies common problems encountered during construction,and proposes solutions.This analysis aims to provide relevant personnel with essential guidance and references for managing electromechanical installation projects safely.
基金The work described here has been supported by the TRANSIT project(funded by EU Horizon 2020 and the Europe’s Rail Joint Undertaking under grant agreement 881771).
文摘Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer functions.It is important,however,to allow for installation effects due to shielding by fairings or the train body.In the current work,fast-running analytical models are developed to determine these installation effects.The model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier model.For equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s functions.The bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field approach.The sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s functions.Results show good agreement with a 2.5D boundary element model and with measurements.Modelling uncertainty and parametric uncertainty are evaluated.The largest variability occurs due to the height and impedance of the ground,especially for a low receiver.This leads to standard deviations of up to 4 dB at low frequencies.For the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.
文摘Translation of specialized documents in optometry presents unique challenges,requiring a deep understanding of the professional context,terminology,and adherence to specific translation styles.This paper delves into the translation theory and techniques employed in the English-to-Chinese translation of the“Optoform 80 Installation and Maintenance Manual”,serving as a case study.Emphasizing Nida’s theory of functional equivalence,the paper explores the complexities of translating professional optometry literature,focusing on key points and common issues in translating installation and maintenance manuals for optometric devices.Special attention is given to the translation of professional terminology,employing methods such as addition,omission,conversion,and repetition.The translation process aims to meet specific requirements,ensuring accuracy and coherence while aligning with Chinese language conventions.The paper also analyzes translation methods and techniques concerning terminology,prepositions,conjunctions,and handling parallel elements based on practical insights from the Optoform 80 Manual.
文摘To better improve the electrical safety of buildings and fulfill the role of lightning protection and grounding,this article combines cases and discusses seven aspects of lightning protection devices’construction technology.These aspects include the lightning protection classification of buildings,air terminals,down conductors,grounding devices,division of lightning protection zones,and lightning electromagnetic pulse shielding.Through the introduction of this article,readers can gain a comprehensive understanding of the application and value of lightning protection grounding construction technology in building electrical installation projects.
基金supported by the National Natural Science Foundation of China-Shandong Joint Fund(Grant No.U2006226).
文摘Compliant vertical access risers(CVAR)have broad application prospects in deep-water oil and gas transportation.However,the mechanical behaviors of the CVAR with a variable length during installation remains unclear.To address this issue,based on the flexible segment method,a model of CVAR with a variable length during installation is established in this study,which is verified by the comparison with commercial software.Then,the mechanical behaviors of CVAR during installation are investigated.The results reveal that the CVAR configuration is significantly affected by the buoyancy blocks.The streamwise displacement of CVAR increases with the increase of current velocity.When the BOP weight is insuffcient,obvious upbending is observed in the lower region and transition region,leading to local compression.When the platform moves in the opposite direction to the current,the maximum stress is larger than that of the scenario when the platform moves in the same direction as the current.
基金financially supported by the National Natural Science Foundation of China (Grant Nos.52371301,51879044 and 51808325)the Shandong Natural Fund (Grant No.ZR2020QE258)。
文摘Suction caissons are widely used for anchoring floating platform and offshore wind turbines.Penetration of the suction caisson into the desired position under the combination of its self-weight and applied suction resulted from pumping out the encased water is integral to practical engineering.Model tests were carried out to investigate the suctionassisted installation of suction caissons in clay under various undrained shear strengths.It was found that there exists a critical penetration depth value.When the penetration depth is smaller than the critical value,the soil plug undrained shear strength is higher than intact clay(i.e.,clay prior to installation).However,when the penetration depth is greater than the critical penetration depth,the undrained shear strength of soil plug is lower than intact clay.The critical value decreases with the increasing consolidation time and undrained shear strength of clay.During suction-assisted installation,cracks occur around suction caissons.The installation way has little effect on the crack formation.The influence range(i.e.,the maximum distance between the crack and the suction caisson edge)was found to increase with the increasing friction coefficient of interface between the suction caisson wall and soil and decreases with the increasing soil undrained shear strength.In addition,the drained condition of the clay during installation is dominated by the caisson aspect ratio,the undrained shear strength and the friction coefficient between the caisson wall and clay.Equations to estimate the penetration resistance and the required suction to install the suction caisson are summarized.
基金funded by Major Science and Technology Projects in Gansu Province(19ZD2GA003).
文摘Because of the randomness of wind power and photovoltaic(PV)output of new energy bases,the problem of peak regulation capability and voltage stability of ultra-high voltage direct current(UHVDC)transmission lines,we proposed an optimum allocation method of installed capacity of the solar-thermal power station based on chance constrained programming in this work.Firstly,we established the uncertainty model of wind power and PV based on the chance constrained planning theory.Then we used the K-medoids clusteringmethod to cluster the scenarios considering the actual operation scenarios throughout the year.Secondly,we established the optimal configuration model based on the objective function of the strongest transient voltage stability and the lowest overall cost of operation.Finally,by quantitative analysis of actual wind power and photovoltaic new energy base,this work verified the feasibility of the proposed method.As a result of the simulations,we found that using the optimal configuration method of solar-thermal power stations could ensure an accurate allocation of installed capacity.When the installed capacity of the solar-thermal power station is 1×106 kW,the transient voltage recovery index(TVRI)is 0.359,which has a strong voltage support capacity for the system.Based on the results of this work,the optimal configuration of the installed capacity of the solar-thermal power plant can improve peak shaving performance,transient voltage support capability,and new energy consumption while satisfying the Direct Current(DC)outgoing transmission premise.
基金Supported by National High Technology Research and Development Program of China("863"Program,No.2012AA051705)National Natural Science Foundation of China(No.51109160)International Science and Technology Cooperation Program of China(No.2012DFA70490)
文摘In 2010,the first offshore wind turbine with integrated installation was established in Qidong sea area of Jiangsu Province,China,which led to the implementation phase of one-step-installation technique based on the design and construction of large-scale bucket-top-bearing (LSBTB) bucket foundation.The critical technique of LSBTB bucket foundation included self-floating towing,penetration with adjustment of horizontal levelness,removability and one-step-installation.The process of one-step-installation included the prefabrication of LSBTB bucket foundation in onshore construction base,installation and debugging of wind power,overall water transportation of foundation and wind power system,and installation of foundation and offshore wind turbine on the appointed sea area.The cost of one-step-installation technique was about 5 000 Yuan/kW,which was 30%-50% lower than that of the existing technique.The prefabrication of LSBTB bucket foundation took about two months.During the one-step-installation process,the installation and debugging of wind power and overall water transportation need about one to two days in sea area within 35 m depth.After the proposed technique is industrialized,the cost will be further reduced,and the installation capacity is expected to be up to 500 wind turbines per year.
基金supported by Marine Engineering Equipment Scientific Research Project of Ministry of Industry and Information Technology of PRC and the Application of float-over installation simulation in Wangchang Project of CNOOC Technology ProjectThe Fundamental Research Funds for the Central Universities(HEUCF170102)
文摘In this paper,a numerical investigation of a float-over installation for an offshore platform is presented to verify the feasibility of the actual installation.The hydrodynamic performance of a T-barge is investigated in the frequency domain,and the coupled motions are analyzed in the time domain.We then compare with those of the model test and determine that the response amplitude operator and the time series agree quite well.The barge exhibits favorable hydrodynamic behavior in the considered sea state,and the equipment loads are allowable.Themooring systemand sway fender forces are within the permissible range.Based on these results,we can verify that the actual installation of the offshore platform is feasible.We accurately simulated many important factors and effectively reduced the risk associated with the offshore installation,which is of great importance.As such,we demonstrate that the numerical simulation of the float-over installation for offshore platforms has practical engineering significance.
基金financially supported by the National Natural Science Foundation of China(Grant No.52071336)the National Key Research and Development Program of China(Grant No.2016YFC0303701)+1 种基金the Ministry of Industry and Information Technology Special Project(Grant No.2018GXB01-07)the CNOOC Limited Shenzhen Branch(Grant No.CCL2019SZPS0541)。
文摘The subsea suspended manifold designed to replace the traditional foundation structure with the buoys is a new generation subsea production system that can be suspended at a certain height from the seafloor and rapidly recycled by its own buoyancy.Due to complex environmental conditions,its hydrodynamic performance in the splash zone is extremely important for the safety of the whole installation process.In this paper,the mathematical model for the dynamic analysis of the seawater ingress process of the single-layer pre-set horizontal cabin is proposed based on the different center of gravity positions of the buoy.Meanwhile,the theoretical analysis of fiber cable is divided into infinite differential units by the discretization method,and the formulae of the horizontal displacement of the subsea suspended manifold are presented.In addition,the simulations are carried out to verify the rules of the dynamic responses on the subsea suspended manifold system with the consideration of the environmental conditions in the South China Sea.Comparing with the calculated value of the mathematical model of the cabin water ingress,the error of the simulation result by use of FLUENT is about 5.47%.Furthermore,the wave height is greater than the current impact on the lowering manifold system and the azimuth angle of the installation vessel is aligned with the direction of the environmental load.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 51809231 and 51988101)。
文摘A new dynamically installed plate anchor, the Flying Wing Anchor~?, has been developed as a sustainable anchor concept for deep-water offshore wind turbines. The anchor is firstly installed by free-fall penetration and then followed by drag embedment. If the anchor is subjected to environmental loads, it dives deeper to mobilize a higher capacity. This study presents a series of free-fall penetration tests with model anchors in different weights to assess the anchor behavior during the free-fall penetration performance in one-layer soil with a constant shear strength profile. Anchor velocities and embedment depths were measured by a magnetometer. An energy-based model and a force-based model were calibrated against the test results of model anchors with different weights. Based on the calibrated force-based model, a series of design charts were developed to estimate the embedment depth of anchors in different sizes and with different impact velocities in various marine clays. The framework to plot design charts presented herein can be potentially applied to other dynamically installed anchors to predict embedment depth in engineering practice.
文摘Solar Photovoltaic (PV) can be considered as one of the most reliable and promising renewable systems. This is of great importance for developing countries like Nigeria especially in the rural communities where there is little or no access to electricity. The use of solar energy will no doubt contribute to the improvement of the living conditions of these villagers. Solar PV systems have been installed in some villages in Nigeria but unfortunately, the expected benefits from using these systems have been jeopardized. The objective of this work is to embark on performance assessments of in- stalled Solar PV system in Oke-Agunla, Akure local government of Ondo State in Nigeria. Visits were conducted to the village;equipments on ground were examined while the people were interviewed. Both functional and non-functional facilities were traced to their manufacturers using the identification data on them and rated to ensure their efficiencies. Energy demands were also prorated, and observed the need to improve on the present energy supplied. Results of the assessments shows that PV facilities used were inadequate, trained technicians were not available giving room for quacks working on the facilities occasionally resulted in further complications and poor facilities maintenance. The assessment result shows that just 14.52% of the 4.5 kW installed solar PV was utilized due to significant malfunctioning and deterioration in performance. It can be concluded from this study that the installed solar PV systems was inefficient as a result of poor maintenance, lack of technical know-how and inability of the project contractors or managers to take these factors into consideration while embarking on the solar PV installations.
