ABSTRACT
The energy-efficient plate heat exchanger (PHE) and refrigerant R1234yf, which has a low global warming potential (GWP), can be used to realize an energy efficient heat pump (HP) system for electric vehicles (EV), extending their driving range. Therefore, the characteristics of R1234yf in an offset-fin strip (OSF) flowstructured PHE are critical for heat-exchanger design. This study investigates the condensation heat transfer coefficient (C-HTC) and two-phase frictional pressure drop (2P-FPD) of R1234yf during condensation in an OSF flow-structured PHE under various operating conditions. First, a modified Wilson plot method was used to determine the multiplier (C) and Reynolds number exponential (n) for the coolant side as -0.426 and 0.494, respectively. When the heat flux (q), average vapor quality (xa), and mass flux (G) increased, the C-HTC increased, whereas it decreased with saturation temperature (Tsat). Despite the force-convective condensation flow regime, the C-HTC increment was minimal with G at lower xa owing to the lesser significance of the shear effect. Additionally, the 2P-FPD was unaffected by q but increased considerably with an increase in xa and G and a decrease in Tsat. Based on the current experimental database, empirical correlations for forecasting friction factor and Nusselt number were developed with a 91% predictability.
ABSTRACT
The structure of the presentation will be 1) Pandemic-Epidemiology 2) General Pandemic-Management 3) HRT and COVID 4) Different spectrum of menopausal symptoms (Europe/Asia) 5) Different risks lead to different HRT. 1) Pandemic-Epidemiology: SARS-COVID-19 has got to be a new disease, China was the first to suffer from the pandemic starting in December 2019 with spread all over the world. Diagnosis, treatment and protective measures have started in Europe in March 2020;up from autumn 2022 in Europe the pandemic changed to endemic, but protective measures still should be continued in risk patients like in hospitals and nursing homes. Rehabilitation will for long-time be an issue like treatment of "Post-" and "Long-COVID". China pursued a zero-COVID-policy until Dec 2022. The sudden stop of almost all measures led to a sharp increase in infections, which shows that the disease will remain a global risk. 2) General Pandemic-Management: Protective measures like vaccination, surgical masks, screening/testing, isolation management, travel/residence history in high-risk regions, education of patients and families had to be the first priority, ahead of other issues such as the management of menopause. 3) HRT and COVID: Already the first prelimary data assessed in Wuhan/China have shown that women with low estradiol-levels had more severe infections with COVID. An analysis of health records of 68,466 COVID-positive patients from 17 countries showed that the fatality risk for women > 50 years receiving HRT was reduced by more than 50% compared to those women not taking HRT (Seeland, 2020). Likewise from a case-control study analyzing the self-reported data of 1.6 million UK menopausal women through the COVID-Symptoms Study Smartphone application (control populations adjusted for age, body mass index, and smoking status) was concluded, that HRT not only can be used, but even can protect from COVID-infections and/or their sequelae (Costeira, 2021). 4) The different spectrum of menopausal symptoms (independent of COVID-infections) comparing data in Europe (showing more vasomotor symptoms) and China (more somatic symptoms) will be presented, including own data. 5) Different risks during HRT consequently lead to different use of HRT, especially more transdermal estrogen combined with progesterone in Europe due to much higher VTE-risk, but more management of the high bleeding-problems in China using individualized (mostly oral) estrogen/progestogen combinations. Copyright © 2023
ABSTRACT
This paper argues that the crisis in humanity's relationship with water reflected in rapidly escalating demand and dangerously depleting freshwater and groundwater reserves, can be understood as the outcome of the anthropocentric assumptions underlying our current development models. These assumptions have given rise to both the challenge of severe water scarcity as well as to the kind of policies used to address it. Drawing on principles from an environmental justice framework, it calls for a drastic restructuring of the water sector on more equitable, sustainable and democratic lines. Some of the guiding principles for water governance that are suggested include ensuring that interventions in nature or river systems are along the contours of nature, focusing on managing the demand for water as against the present emphasis on supply augmentation, recognition of structural and historical inequities which determine access to water, adoption of an approach to water management that is adaptive to rapidly changing circumstances and promotion of the participation of all stakeholders in governance and knowledge production. © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2023.
ABSTRACT
A casing leak repair alternative is presented to allow continued hydraulic fracture treatment of an unconventional formation. Analysis of diagnostic operations, selection of the best alternative, and the results are detailed. This paper details the diagnostic operations (annular circulation test, multifinger caliper log, leak chase with hydraulic packer on Coiled Tubing, fluid transit evaluation, and real-time camera downhole images acquisition) to identify the casing leak zone and the analyzed repair alternatives with the final selection of a casing patch. To verify the pipe body shield strength and burst pressure post-patch expansion, a finite element analysis in dynamic condition was carried out to limit the hydraulic fracture pumping parameters. This paper covers details on repair operations executed, verification analysis to confirm original frac treatment continuity, and lower & upper completion installation. The diagnostics operations allowed pinpointing casing leak detection and selection of possible repair alternatives. The repair was carried out as planned involving many services companies. A solution was implemented with local staff and services considering the COVID context with travel restrictions of the patch owners. Web broadcasting CT surface parameters allowed real-time support from casing patch suppliers during the entire intervention. The completion plan with 24 frac stages performed through the casing patch was successfully executed. The production packer with an OD of 99.5% of the casing patch drift was run through the casing patch and wireline set without any problem. Considering well integrity conditions throughout the entire well production life as the main intervention objective, this paper introduces a successful alternative to repair casing failures on an unconventional well that allowed hydraulic fractures continuity to accomplish the original frac plan. The well production was higher than the Estimated Ultimate Recovery (EUR) expected for the landing zone. Copyright 2023, Society of Petroleum Engineers.
ABSTRACT
The root tuber of Pinellia ternata has been used as a traditional therapeutic herbal medicine. It is reported to impart beneficial attributes in recovering COVID-19 patients. To meet an increasing demand of P. ternata, this study is intended to investigate the effects of biochar on the soil hydrological and agronomic properties of two decomposed soils (i.e., completely decomposed granite (CDG) and lateritic soil) for the growth of P. ternata. The plant was grown in instrumented pots with different biochar application rate (0%, 3% and 5%) for a period of three months. Peanut shell biochar inclusion in both soils resulted in reduction of soil hydraulic conductivity and increase in soil water retention capacity. These alterations in hydrological properties were attributed to measured change in total porosity, biochar intra pore and hydrophilic functional groups. The macro-nutrient (i.e., N, P, K, Ca, and Mg) concentration of both soils increased substantially, while the pH and cation exchange capacity levels in the amended soils were altered to facilitate optimum growth of P. ternata. The tuber biomass in biochar amended CDG at all amendment rate increases by up to 70%. In case of lateritic soil, the tuber biomass increased by 23% at only 5% biochar application rate. All treatments satisfied the minimum succinic acid concentration required as per pharmacopoeia standard index. The lower tuber biomass exhibits a higher succinic acid concentration regardless of the soil type used to grow P. ternata. The biochar improved the yield and quality of P. ternata in both soils.
ABSTRACT
La eficacia de las estrategias de la administración pública se ha medido en la forma en que manejan las pandemias y los efectos en cadena que se producen en el medio ambiente o la sociedad, y en este caso, en el abastecimiento de agua rural en México en tiempos de pandemia. El acceso al agua en las zonas rurales de México y cómo el gobierno ha manejado el aumento de la demanda durante las pandemias se exploran mediante una revisión sistemática de 51 documentos. El sistema de agua de México está por debajo de la media y es necesario realizar más inversiones en los planes de gestión comunitaria. Se requiere la participación de la ciudadanía en el desarrollo de esquemas de gestión comunitaria para encontrar una solución a la demanda y oferta cambiantes.Alternate :The efficacy of public administration strategies has been gauged on how they handle pandemics and the knock-on effects that occur on the environment or society, and in this case, in the rural water supply in Mexico in times of pandemics. Water access in rural Mexico and how the government has managed the rise in demand during pandemics are explored using a systematic review into 51 documents. Mexico's water system is below par and there is a need for more investments to be pumped into community management schemes. The involvement of the public in the development of community management schemes is necessary to find a solution to the changing demand and supply.
ABSTRACT
The Cheleken field offshore Turkmenistan is going through brown field development and challenges with retaining and enhancing production increase every day. Well Interventions are deemed to be a daily necessity to maintain production. Coiled Tubing, Wireline and other rigless interventions have been used directly on platforms resulting in occupying critical spaces, logistic and marine congestion (one Coiled Tubing Move comprises of over twenty lifts), structure integrity limitations, crane and lifting limitation, and a lot more. The need for a self-elevating platform arose and operator search for a proper one within the Caspian Sea ended with disappointments. This paper details the innovative and out of the box solution that was put in place to mobilize the first Lift Boat to the Caspian Sea. A lift boat was identified in the USA in the Gulf of Mexico which was underutilized after the pandemic and oil recession. The Class 230 specifications met the end user's requirements but the challenge was how to mobilize it to the Caspian. In addition, there were a handful of modifications that were requested for the Caspian operation that were not necessarily required in the Gulf. Mobilization of the lift boat must be carried out through the Volga-Don canal locking system which has a width of 57 feet 9 inch (maximum allowable beam for vessels is 56 feet 5 inches). The beam of the lift boat was 78 feet which is too wide to fit through the Volga-Don shipping canal. Hence, it was necessary to disassemble and transport the lift boat in sections. This paper describes the following: • Disassembly requirements necessary to prepare the lift boat for mobilization • The mobilization of the lift boat • • Installation of well service and intervention equipment • Technology and methodology adopted The reassembly requirements once the lift boat reached the shipyard at Caspian Sea The Lift boat was disassembled into three major sections for transportation: a) the center hull module b) the port wing module, and c) the starboard wing module. The wing modules, miscellaneous equipment and containers were loaded onto a barge and sea-fastened for transportation. The center hull module was wet towed to the shipyard located in the Caspian where the lift boat was reassembled, and the well service equipment was installed. The mobilization and assembly happened during the Covid-19 era, and the vessel was hit by Hurricane Ida which impacted the disassembly schedule. Challenges on mobilizing the personnel, equipment, machinery, port clearance, etc. were all extremely tough due to Covid-19. The paper will also cover technical implications on conducting this task by complying with the classification and flag state requirements as per Turkmenistan authority. The main lesson of the paper is the identification of gaps on mobilization and how the improved techniques can be utilized for executing the task on a fast-track manner. © 2023, Offshore Technology Conference.
ABSTRACT
Masks are the primary tool used to prevent the spread of COVID-19 in the current pandemic. Tests were carried out to determine the total pressure drop through the materials from which the masks are made and the correlation of these results with the concentration of carbon dioxide in the inner space of the mask. The results showed that a parameter representing hydraulic losses of the mask material has a significant influence on the concentration of carbon dioxide in the inner space of the mask. Masks with higher hydraulic resistances accumulated a higher concentration of carbon dioxide, and generated greater fluctuations of carbon dioxide as a function of time, which may be caused by compensation of the respiratory system. For example, in a two-layer mask (mask no. 3) the hydraulic resistance values are about three times higher than in a single-layer mask (mask no. 1). The study also noticed that the inscriptions and prints placed on the masks increase the hydraulic resistance of the material from which the masks are made, which may also contribute to the accumulation of carbon dioxide in the space between the mask and the face. To reduce the accumulation of carbon dioxide within the inner space of the mask, the results of this work suggest searching for mask materials with the lowest possible hydraulic resistance.
ABSTRACT
In this work, a novel approach for airborne filtration with particular reference to medical (non-oil) medical mask is discussed. Here, and contrariwise to current approaches, filtration is attained neither by reducing the hydraulic diameter of the pore nor by increasing the fibre layers thickness-both of them with a strong penalty in the breathability of the mask, but rather by aerodynamic focussing and growth of the particles themselves. Aerodynamic focussing of particles is achieved by a proper simple parallel rearrangement of the traditional crisscrossing fibres-a configuration which we called the aerolayer;and the growth by coalescence. Utilizing a simplified geometrical and physical model, an expression for the required length of the aerolayer was derived. It is shown that the aerolayer is not only able to increase the probability of capture for small particles but also can potentially improve the breathability by reduction of the total thickness of the current layers required. Additional R &D is required in order to arrive to the most optimized practical design of the aerolayer. © 2023, Indian Academy of Sciences.
ABSTRACT
The Port of San Diego's B Street Pier facility (Pier) is the busiest cruise terminal in the City of San Diego with over a hundred ship calls annually (pre-COVID). The Pier is an approximately 9.4-acre bulkhead faced mole extending about 1,000 ft into San Diego Bay and approximately 400 ft wide. On the three offshore sides of the bulkheaded mole are marginal pile supported wharfs constructed in 1923. The upland side of the mole is a concrete gravity seawall constructed in 1900. The mole soils consist of hydraulically placed dredge spoils and are susceptible to liquefaction.The existing Pier containment walls are deemed inadequate for seismic loading, mainly due to the presence of liquefiable materials both in front of and behind the existing containment wall. A solution consisting of an improved Deep Soil Mixing (DSM) zone coupled with the installation of a new steel sheet bulkhead was selected to retrofit and upgrade the Pier to current seismic standards. A key aspect of the design was to minimize loading induced from the wharf onto the existing curtain wall during an earthquake. The DSM zone is intended to serve a triple purpose, that is to improve shear strength of the soils behind the curtain wall, to mitigate the impact of liquefaction, and to provide sufficient bearing for potential future lightly loaded structures which may be constructed on the Pier. To obtain a cost-effective design and limit the DSM zone extents, the design also needed to limit the seismic load contributions to the DSM from the marginal wharves during seismic conditions. A development plan consisting of a multi-phased construction plan was determined to meet the Port's capital improvement needs and budget. Phase I development will install the DSM zone and steel sheet pile bulkhead along the south and west face of the mole. Future work will include wharf pile and deck replacement along with completing curtain wall replacement along the north face of the mole. This paper presents the geotechnical design challenges and considerations associated with the design of the DSM and sheet pile system comprising Phase I of the development plan. Key aspects of the geotechnical design included the selection of appropriate liquefaction resistance of the DSM improved zone, designing for the lateral spread of the slope in front of the curtain wall, assessment of stability and deformation of the proposed sheet pile, and the determination of the seismic earth pressures. © ASCE.
ABSTRACT
During the COVID-19 pandemic, urban forest parks are becoming increasingly significant for recreation and relaxation, not just for urban residents but also for tourists. This study empirically examined the structural relationships among first-time visitors' perceptions of destination image, perceived value and destination loyalty through structural equation modeling. Additionally, the mediating influence of perceived value and the moderating effect of gender were investigated as well. The Grand Canal Forest Park in Beijing was selected as the case study. In total, 486 questionnaires that were considered to be legitimate were gathered and afterwards analyzed. The results revealed that first-time visitors' perceptions of destination image can positively and significantly affect their perceived value and destination loyalty. In addition, perceived value partially mediates the relationship between first-time visitors' perceptions of destination image and destination loyalty. Moreover, the findings of the examination of the moderating effects showed that gender has substantial moderating effects on the relationships described above. The theoretical and practical implications, limitations and future research of the current study are also discussed. © 2023 by the authors.
ABSTRACT
Disruptions in maritime networks may cause significant financial burden and damage to business. Recently, some international ports have been experiencing unprecedented congestions due to the COVID19 pandemic and other disruptions. It is paramount for the maritime industry to further enhance the capability to assess and predict impacts of disruptions. With more data available from industrial digitization and more advanced technologies developed for big data analytics and simulation, it is possible to build up such capability. In this study, we developed a discrete event simulation model backed with big data analytics for realistic and valid inputs to assess impacts of the Suez Canal blockage to the Port of Singapore. The simulation results reveal an interesting finding that, the blockage occurred in the Suez Canal can hardly cause significant congestion in the Port of Singapore. The work can be extended to evaluate impacts of other types of disruptions, even occurring concurrently. © 2022 IEEE.
ABSTRACT
Traditional hydraulic drive experiments present a number of challenges. During the hydraulic transmission experiment, the equipment is easily damaged and must be frequently updated, which makes it difficult for a large number of students to study at the same time;the traditional offline, monotonous, and boring experiments make it difficult for students to increase their interest in learning from what is inherent;and most undergraduate students have to study at home due to the impact of COVID-19. Therefore, students need an excellent teaching system that allows them to perform experiments at home and improve their learning efficiency. A teaching system for the undergraduate hydraulic transmission course was designed to meet the needs of the hydraulic transmission course and to stimulate students' interest in learning. This teaching system allows students to spend more time outside of the class to analyze experimental results and relate concepts presented in lecture courses to experimental results. Finally, a course on hydraulic drives taught at Nanchang University was used to evaluate the effectiveness of this teaching system. The analysis based on positive student feedback and academic performance shows that the proposed teaching system is an effective learning tool for undergraduate students in their learning process. © 2023 by the authors.
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We are pleased to provide you with the proceedings of 2022 4th International Conference on Resources and Environment Sciences (ICRES 2022).The conference was expected to be held during June 10-12, 2022 in Bangkok, Thailand, while the situation of COVID-19 pandemic is unpredictable and unstable. Most of conference participants could not travel to attend the conference venue to do oral presentations. Taking all conditions into consideration, conference committee decided to change physical conference into virtual conference. It was held online by ZOOM application successfully during the same date.The conference was highlighted by four outstanding Keynote Speakers and two invited speakers. Keynote speakers include Prof. Kaimin Shih, The University of Hong Kong, China with his topic "Metal Stabilization and Resource Recovery Examples in Urban Environment”;Prof. Nur Islami, University of Riau, Indonesia who presented a talk on "An Valuable Approach to Study Groundwater Contamination in a Shallow Aquifer System”;Prof. Danny Sutanto, University of Wollongong, Australia who shared a speech on "Solid-State Transformer for Smart Power Grid Applications”;Assoc. Prof. Phebe Ding, Universiti Putra Malaysia, Malaysia who presented a talk about "Role of Postharvest Technology in Producing Quality Fresh Horticultural Produces”. Additionally, two excellent invited speakers, Assoc. Prof. Chunrong Jia from University of Memphis, Tennessee, USA with speech title "Apportioning variability of polycyclic aromatic hydrocarbons (PAHs) in the ambient air in the Memphis Tri-State Area, USA”, and Assoc. Prof. Farhad Shahnia from Murdoch University, Australia with speech title "Recent and Future Research on Microgrid Clusters”.Each normal oral presenter had about 12 Minutes of Presentation and 3 Minutes of Question and Answer. Conference was organized in 5 sessions with various topics: Environmental Management, Waste Utilization and Sustainable Development, Wastewater Treatment, Water Analysis and Hydraulic Engineering, Renewable Energy Technology, Chemical Engineering and Fluid Mechanics, Resources and Environmental Science & Sustainable Development, Energy and Chemical Engineering.All accepted papers presented at the ICRES 2022 were included in this volume, which contained three chapters with topics: (1) Environmental Pollution and Control (2) Waste Management and Utilization (3) Clean Energy and Technology. All papers were subjected to peer-review by conference committee members and international reviewers. The papers were selected based on high quality and high relevancy to the conference scope.We would like to express our sincere gratitude to organizing committee and the volunteers who have dedicated their time and efforts in planning, promoting, and helping the conference. We hope that the readers would gain some valuable knowledge from this effort.List of Committees, Statement of Peer Review are available in this Pdf.
ABSTRACT
Formation damage in drilling comes from drilling fluid invasion due to high differential pressure between a wellbore and the formation. This mechanism happens with fracture fluid invasion of multi-fractured horizontal wells in tight formations. Some multi-fractured wells show production rates and cumulative productions far lower than expected. Those damaged wells may sustain further impact such as well shutting due to unexpected events such as the COVID-19 outbreak and then experience a further reduction in cumulative production. This paper focuses on the root causes of formation damage of fractured wells and provides possible solutions to improve production. A simulation study was conducted using Computer Modelling Group software to simulate formation damage due to fracture fluid invasion and well shut-in. Simulation results revealed that the decrease in cumulative hydrocarbon production due to leak-off and shut-in of the simulated well could range from 20 to 41%, depending on different conditions. The results showed that the main causes are high critical water saturation of tight formations, low drawdown, and low residual proppant permeability under formation closure stress. The sensitivity analysis suggests two feasible solutions to mitigate formation damage: optimizing drawdown during production and optimized proppant pack permeability of the hydraulic fracturing process. Optimizing pressure drawdown is effective in fixing leak-off damage, but it does not mitigate shut-in damage. Formation damage due to shut-in should be prevented in advance by using an appropriate proppant permeability. These key findings enhance productivity and improve the economics of tight gas and shale oil formations.
ABSTRACT
During the twentieth and twenty-first centuries, the oil industry has been pivotal in influencing all countries' geopolitical, economic, and human development strategies. Until recently, the debate was about peak oil and what would happen after oil finished. However, due to technological advances and hydraulic fracturing, shale oil formations have become economically viable due to the United States' desire to achieve energy security to make a qualitative shift in the oil industry and the geopolitics of oil. Therefore, this paper deals with an economic model that illustrates the impact of oil price fluctuations to the shale oil and gas companies by analyzing the main determinants of continuity of shale oil and gas companies in production if global oil prices decline or rise. In addition, the study will investigate the effects of OPEC+ policy and Covid-19 on the future of shale oil industry. The study will discuss some future scenarios for global energy trends and predict what the shale industry will look like in the future. The study concluded the shale industry faces an internal destructive process (within the industry itself) and external (Renewable energy, OPEC and Covid-19). The stability of oil prices is a critical factor that promotes the shale industry's recovery. However, shale industry is expected to continue with low productivity growth rates and continuing government support for it. © The Author(s) 2022.
ABSTRACT
In July 2020, the Kyushu region experienced record-breaking heavy rains from July 4-7, causing extreme floods in the Kuma and Chikugo Rivers. This was followed by atmospheric instability over a wide area from western Japan to the Tohoku region, resulting in heavy rainfall on July 13-14 in the Chugoku region, and on July 27-28 in the Tohoku region, and flooding of large rivers including the Go River and the Mogami River. In recent years, record-breaking torrential rainfall disasters have been occurring every year, and the heavy precipitation scale as well as the rainfall intensity has been increasing in space and time, resulting in spatio-temporal expansion of the damage. Furthermore, in 2020, the disaster occurred while the social activities had been restricted due to COVID-19 pandemic. The compilation and dissemination of disaster survey data and lessons are essential toward the sustainable development of society. Therefore, JSCE has planned a special issue on the July 2020 torrential rain disaster in order to share and disseminate disaster information and to contribute to the advancement of technology and science related to disaster prevention and mitigation.抄録 令和2年7月，九州地方では4日から7日にかけて記録的な大雨となり，球磨川や筑後川では記録的な洪水が発生した．その後も西日本から東北地方の広い範囲で大気が不安定となり，江の川，最上川など大河川においても氾濫が相次いだ．近年では，毎年のように記録的な豪雨災害が発生しており，降雨強度だけでなく降雨のスケールが時空間的に大きくなっており，被害が時空間的に拡大している．さらに，令和2年度は新型コロナウィルスによる感染症対策のため，人々の活動が制限される中での災害となった．災害調査データを取り纏め，情報発信することは今後の持続可能な社会を検討する上で不可欠である．土木学会論文集では，災害情報を共有・発信し，防災に関する技術および学術分野の進展に資するために令和2年7月豪雨災害に関する特集を企画した．
ABSTRACT
Recordable heavy rainfall hit and caused severe floods from the Kuma River in Hitoyoshi and Kuma regions in July, 2020 due to an active frontal rain system. This paper aims to clarify challenges and issues in measures taken by core medical institutions against large-scale floods, which have been identified in the flood event in Kuma River in July 2020, based on the interview with the core medical institution in those regions. The paper then discusses directions for effective flood countermeasures of core medical institutions in order to have more robust Business Continuity Plan (BCP) for large-scale flood disasters.抄録 令和2年7月豪雨災害では，九州地方や東北地方などで大規模な出水となり，中でも九州地方では人的被害を含む甚大な被害が生じた．一方で，本災害は，新型コロナウイルス感染症（COVID-19）が全国的に流行する中で発生した最初の大規模水害であり，特殊な感染症への対応を継続しつつも，大規模な水害が発生した場合に地域の医療機能をどのように維持していくかが大きく問われた災害でもあった．本稿では，人吉・球磨地方における地域医療の拠点病院に対して令和2年7月豪雨災害での球磨川の氾濫に伴う浸水時の状況と対応についてヒアリングを行った結果を報告するとともに，これを踏まえた拠点医療機関の水害対策の課題と方向性について述べる．
ABSTRACT
The present research focuses on analyzing the feasibility of manufacturing complex turbomachinery geometries in a preassembled manner through an uninterrupted additive manufacturing process, absent of internal support structures or post-processing. In the context of the present COVID-19 pandemic, the concept is illustrated by a 3D-printable turbinedriven blower-type medical ventilator, which solely relies on availability of high-pressure oxygen supply and a conventional plastic-printer. Forming a fully pre-assembled turbomachine in its final form, the architecture consists of two concentric parts, a static casing with an embedded hydrostatic bearing surrounding a rotating monolithic shell structure that includes a radial turbine mechanically driving a centrifugal blower, which in turn supplies the oxygen enriched air to the lungs of the patient. Although the component level turbomachinery design of the described architecture relies on well-established guidelines and computational fluid dynamics methods, this approach has the capability to shift the focus of additive manufacturing methods to design for preassembled turbomachinery systems. Upon finalizing the topology, the geometry is manufactured from PETG plastic using a simple tabletop extrusion-based machine and its performance is evaluated in a test facility. The findings of the experimental campaign are reported in terms of flow and loading coefficients and are compared with simulation results. A good agreement is observed between the two data sets, thereby fully corroborating the applied design approach and the viability of additively manufactured pre-assembled turbomachines. Eliminating long and costly processes due to presence of numerous parts, different manufacturing methods, logistics of various subcontractors and complex assembly procedures, the proposed concept has the potential to reduce the cost of a turbomachine to capital equipment depreciation and raw material. Copyright © 2022 by ASME.
ABSTRACT
Hydraulic fracturing (HF) operations are widely associated with induced seismicity in the Western Canadian Sedimentary Basin. This study correlates injection parameters of 12,903 HF stages in the Kiskatinaw area in northeast British Columbia with an enhanced catalog containing 40,046 earthquakes using a supervised machine learning approach. It identifies relevant combinations of geological and operational parameters related to individual HF stages in efforts to decipher fault activation mechanisms. Our results suggest that stages targeting specific geological units (here, the Lower Montney formation) are more likely to induce an earthquake. Additional parameters positively correlated with earthquake likelihood include target formation thickness, injection volume, and completion date. Furthermore, the COVID‐19 lockdown may have reduced the potential cumulative effect of HF operations. Our results demonstrate the value of machine learning approaches for implementation as guidance tools that help facilitate safe development of unconventional energy technologies.Alternate :Plain Language SummaryHydraulic fracturing (HF), a technique used in unconventional energy production, increases rock permeability to enhance fluid movement. Its use has led to an unprecedented increase of associated earthquakes in the Western Canadian Sedimentary Basin in the last decade, among other regions. Numerous studies have investigated the relationship between induced earthquakes and HF operations, but the connection between specific geological and operational parameters and earthquake occurrence is only partly understood. Here, we use a supervised machine learning approach with publicly available injection data from the British Columbia Oil and Gas Commission to identify influential HF parameters for increasing the likelihood of a specific operation inducing an earthquake. We find that geological parameters, such as the target formation and its thickness, are most influential. A small number of operational parameters are also important, such as the injected fluid volume and the operation date. Our findings demonstrate an approach with the potential to develop tools to help enable the continued development of alternative energy technology. They also emphasize the need for public access to operational data to estimate and reduce the hazard and associated risk of induced seismicity.