bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of Pressure Losses and Flow Fluctuations in an Intercept Valve Assembly of an Intermediate-Pressure Turbine Part
Authors: Slama Vaclav , Mrozek Lukas , Rudas Bartolomej , Simurda David , Hala Jindrich , Radnic Tomas 
Published: February 2021

Abstract
A new design of an intercept valve assembly of the intermediate-pressure turbine part of greater power output is investigated in terms of pressure losses and flow fluctuations by using measurement on an experimental valve model. In addition, numerical simulations are used to further clarify measured phenomena. For such valve assemblies, it is important to exactly predict pressure losses and avoid danger of vibrations, which are caused by undesirable flow fluctuations, in order to guarantee valve’s efficiency and operational reliability. For this type of valve, it is especially important for turbine operations in partial loads (off-design conditions). Measurements were carried out in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT) in a modular aerodynamic tunnel. Numerical simulations were carried out in the Doosan Skoda Power Company (DSP) by using a package of ANSYS software tools. The experimental valve model is a scaled model of a real valve assembly. It consists of an inlet pipeline, a stop valve and a control valve including its diffuser and outlet pipeline. Measured regimes were defined by a mass flow rate and a control valve cone lift which can be precisely changed. In order to investigate pressure loses, total and static pressures at valve characteristic locations were measured by using Prandtl probes and wall static pressure taps. In order to measure pressure fluctuations, Kulite fast response pressure transducers were used. They were situated near the valve throat where the flow fluctuations, which are strongly related to a flow separation, are the most visible and influential. Measurement results are compared with numerical results and locations with a flow separation were found. In order to reduce this phenomenon, different valve seat angles were also tested. As a result, a valve design could be optimized and, for a pressure loss prediction, a pressure loss model for this new intercept valve assembly could be created. Therefore, pressure losses in similar valve assemblies can be predicted with required accuracy for each new turbine where modern intercept valves are used. This helps to increase steam turbine efficiency and reduce fuel consumption. Based on pressure fluctuations results, operating conditions at which dangerous flow instabilities occur were identified. It was concluded that there is an operating condition border where the flow field starts to be unstable. As a result, the areas of safe and dangerous operating conditions can be predicted so that the operational reliability of the valve can be guaranteed.
Design Strategy for Fixed Sunroof System
Authors: Huang Hailing , Zhang Yuxiang , Sui Hua 
Published: February 2021

Abstract
Fixed Sunroof System (FSS), which consists of a large size heat-strengthened roof panel glass, locating components, encapsulation, etc., is replacing traditional metal roof panel on vehicle to achieve weight reduction as well as providing a broad vision above passengers. As a result of the roof panel glass surface area and curvature, FSS could not be self-fixed on vehicle bodyside outer by means of its locating components currently and a tooling fixture is needed when the fixed sunroof be assembled to vehicle. Meanwhile, varied status of the interferences between FSS and vehicle outer or inner sheet metal may introduce additional loading forces while assembling. That could involve perceived quality issues on its appearance. At the same time, safety performance of FSS also leads a critical role on replacing traditional metal roof panel. This paper is aimed to present a comprehensive design strategy for FSS to achieve self-fixed to vehicle sheet metal as well as robust and sufficient assembly process. For the part of self-location, the concepts are divided to two major directions: location pins’ layout and pins’ structure. A reasonable layout and a new-developed structure of the location clip are essential to make sure the operators could see the clips clearly when assembly, which also conducive to avoid over-positioning. In addition, the fixed sunroof cannot be a naked glass because of appearance reason and seal function requirement. The relationship between loading force and encapsulation’s structure, material and interference volume distributed on the FSS should be established with the purpose of optimizing assembly process and improving interference performance.
This study also develops into detail by experimental and finite element analysis method to figure out the contribution on loading force from encapsulation’s structure, material and interference volume. Moreover, the strength of the FSS can be taken depends on is manufacture process and the shape of the glass. The key elements in manufacture process and the feasibility of further optimization can be identified by means of theoretical in the formation of glass stress. The effect of the fixed sunroof on entire vehicle can be estimated by FE analysis. This paper combines the traditional process with these new-optimized elements, which creates a new manufacture process to achieve a heat-strengthened roof panel glass with lager surface and high rigidity taking the reference of the production process in windshield and backlite. A detection method on glass strength and stiffness can also be figured out during the study in this new manufacture process.
Construction-Scale Concrete Additive Manufacturing and its Application in Infrastructure Energy Storage
Authors: Atkins Celeste , Betters Emma , Boulger Alex , Chesser Phillip , Heineman Jesse , Hun Diana , Lapsa Melissa , Loy Amy , Roschli Alex , Vaughan Joshua , Wang Peter , Post Brian 
Published: February 2021

Abstract
Construction is filled with labor intensive, hazardous, and often wasteful processes. It is also an enormous industry, so improvements in efficiency could have a tremendous economic impact. Construction-scale additive manufacturing is one path toward achieving those improvements. In this paper, a construction-scale additive manufacturing system, called Sky-BAAM, is presented. In addition to possibly leading to more energy-efficient construction practices, leveraging additive manufacturing in construction opens the solution space to more energy efficient building design. One such design, the EMPOWER wall, is also presented in this paper. The exterior of the wall is shaped to maximize heat transfer, while acting as form work for an internal energy-storage system. This allows energy to be stored in the wall during off-peak times and retrieved during peak periods.
Numerical Analysis on the Stability Conditions of an Electrohydrodynamic Jet
Authors: Cândido Sílvio , Páscoa José C. 
Published: February 2021

Abstract
The Taylor cone jet is a well-known electrohydrodynamic flow (EHD), usually produced by applying an external electric field to a capillary liquid. The generation of this kind of flow involves a multi-phase and a multi-physics process and its stability has a specific operation window. This operating window is intrinsically dependent on the flow rate and magnitude of the applied electric voltage. In case high voltages are applied to the jet it can atomize and produce an electrospray. Our work presents a numerical study of the process of atomization of a Taylor cone jet using computational fluid dynamics (CFD). The study intents to assess the limit conditions of operation and the applied voltage needed to stabilize an electrospray. The numerical model was implemented within OpenFOAM, where the multi-phase hydrodynamics equations are solved using a volume-of-fluid (VOF) approach. This method is coupled with the Maxwell equations governing an electrostatic field, in order to incorporate the electric body forces into the incompressible Navier-Stokes equations. The leaky-dielectric model is used and, therefore, the interface between the two phases is subject to the hydrodynamic surface tension and electric stress (Maxwell stress). This allows a leakage of charge though the phase due to ohmic conduction. Thus, the permittivity and conductivity of the phases are taken into consideration. A two-fluid system with relevant electric properties can be categorized as, dielectric-dielectric, dielectric-conducting, and conducting-conducting considering the electrical conductivity and permittivities of the participating phases. Due to the usage of the leaky-dielectric model, it is possible to simulate any of this physical situations. By increasing the applied voltage reaches a value where the cone instability is verified, allowing a discussion on this effect. It is demonstrated that to adequately model the process of atomization a fine grid refinement is needed. The validation of the numerical model is made by comparing against diverse experimental data, for the case of a stable jet. The diameter and velocity of the droplet and the electric current of the jet are the main variables that are compared with previous results. The tests were performed with Heptane. The cone and the jet are strongly affected by the flow rate. The dimensionless diameter, as a function of the dimensionless flow rate, agrees with the scaling laws. The model predicts accurate results over a wide range of flow rates with an accuracy of around 10%. The results are obtained using structured meshes.
Hydrogen Fast Fill Modeling and Optimization of Cylinders Lined With Phase Change Material
Authors: Liszka Miroslaw , Fridlyand Aleksandr , Jayaraman Ambalavanan , Bonnema Michael , Sishtla Chakravarthy 
Published: February 2021

Abstract
This work is a continuation of a previous study (IMECE2019-11449) which sought to explore the feasibility and means of successfully modeling the hydrogen fast filling process of cylinders lined with phase change material (PCM) entirely in CFD software. The first focus of this work was to address the simplistic approach of how the liner temperature was modelled in the previous study. Previously, the entire liner was assigned a single temperature which was obtained and updated through the lumped heat capacity method. This meant that the hotter gas at the end of the cylinder opposite the inlet was in contact with a liner at a temperature lower than could realistically be expected. This was remedied by splitting the liner into four sections. Two sections were used for the curved portions at each end of the cylinder, and the straight wall section was split into two. Each section had its temperature independently calculated through the lumped heat capacity method. A temperature difference on the order of a ten degrees Celsius was observed between the different sections of the liner prior to latent heating beginning. The mass averaged temperature of the hydrogen inside the cylinder obtained with the sectioned wall case matched that obtained with the single wall temperature almost exactly, less than a degree difference.
Despite the unexpected findings of the average hydrogen temperature not changing much when the wall is split into sections, this approach was still taken with all the cases completed in this study. The liner could be split into a greater amount of sections than four, but this was considered unnecessary due to the findings regarding the overall hydrogen temperature. Four sections were considered adequate and used to model the temperature gradient along the wall or liner. The effect of gravity on the filling process was also explored based on the orientation of the cylinder. This required completing three-dimensional simulations to accurately simulate buoyancy driven flow in horizontally mounted cylinders.
All the simulations were completed with ANSYS Fluent 2019 R1 without the use of additional software to handle the heat transfer involving the PCM. All simulations were completed with the coupled pressure-based solver and K-Omega SST turbulence model. The gas properties were obtained from tables generated from NIST properties (REFPROP) available within ANSYS Fluent to limit the amount of error in the accumulated mass within the cylinder due to inaccurate gas properties. The initial conditions for the gas and liner temperatures were 25°C and 100 bar for the gas pressure. A constant mass flow rate of 0.02174 kg/s at a temperature 0°C were used as the initial conditions for the inlet hydrogen gas.
Simulation of a Hydraulic Pulsation Dampener Used for Pulsation Reduction Induced by Vibrations in a Hydraulic System
Authors: Von Dolln William , Duan Shanzhong (Shawn) 
Published: February 2021

Abstract
To reduce vibration-induced pulsations, various devices have been developed, including diaphragm chamber system or gas bladder, non-intrusive fluid wave actuator and fluid filled also known as reflection-type dampeners. However, they are not suitable used in a hydraulic system powered by a triplet piston pump. For example, pulsation dampeners incorporating gas bladders are effective, but there are a number of drawbacks. Loss of gas charge, incorrect gas charge or volume/mass ratio, elastomeric rupture, narrow range of pressure operation and pump speeds, routine maintenance, ineffective location and branch connection instead of in-line configuration are all integrity issues which the industry faces. In addition to having a structural integrity issue, branch connected devices do not perform as efficiently as in-line devices. If a pulsation dampener is responsible for safeguarding critical equipment or systems, premature rupture of a gas bladder can be catastrophic.
This paper introduces a dynamic model and mathematical formulations of a spherical liquid pulsation dampener (U.S. patent number 3731709) that is commonly used to reduce harmful pulsations induced by a triplet piston pump source in fluid power systems. Based on the mathematically proven formulations, computer simulations and optimization procedures were developed in MATLAB to validate the model. Simulation results were then compared with field testing data to numerically verify the model and formulations. For the sake of simplicity, in this paper the pulsation dampener is in conjunction with a three-piston horizontal pump referred to as a triplex pump. The foundation of the simulation is based on a transfer function developed by electrohydraulic analogy resulting in a resistance-impedance-based model. This model takes into consideration all the components of the pulsation dampener and allows for a detailed relationship to its primary function of reducing magnitude spikes. After nonlinear impedances were linearized, MATLAB codes were able to recreate pressure pulsations before and after the pulsation dampener was applied to the system. This allowed for a comparison with field testing data, including mean pressures and range of pressure changes. The mean pressure values examined included 6.08 MPa, 15.20 MPa and 30.40 MPa. The key characteristics to properly analyze the comparison. The wave representing the pressure change over time via MATLAB and that of the field testing were consistent in pulsation reduction. With the validity of the transfer function confirmed, a meta-heuristic approach was utilized to find optimized dimensions of the pulsation dampener while maintaining the desired magnitude reduction. This method can be used to hone the precise dimensions for a variety of functions and even further reduce pulsations.
Sepsis in patients with haematological versus solid cancer: a retrospective cohort study
Authors: Bou Chebl Ralphe , Safa Rawan , Sabra Mohammad , Chami Ali , Berbari Iskandar , Jamali Sarah , Makki Maha , Tamim Hani , Abou Dagher Gilbert 
Published: February 2021

ObjectivesThis study aims to examine the outcome of haematological and patients with solid cancer presenting with sepsis to the emergency department (ED).DesignSingle-centred, retrospective cohort study. Setting conducted at an academic emergency department of a tertiary hospital.ParticipantsAll patients >18 years of age admitted with sepsis were included.InterventionsPatients were stratified into two groups: haematological and solid malignancy.Primary and secondary outcomeThe primary outcome of the study was in-hospital mortality. Secondary outcomes included intensive care unit (ICU) mortality, ICU and hospital lengths of stay and mechanical ventilation duration.Results442 sepsis cancer patients were included in the study, of which 305 patients (69%) had solid tumours and 137 patients (31%) had a haematological malignancy. The mean age at presentation was 67.92 (±13.32) and 55.37 (±20.85) (p<0.001) for solid and liquid tumours, respectively. Among patients with solid malignancies, lung cancer was the most common source (15.6%). As for the laboratory workup, septic solid cancer patients were found to have a higher white blood count (12 576.90 vs 9137.23; p=0.026). During their hospital stay, a total of 158 (51.8%) patients with a solid malignancy died compared with 57 (41.6%) patients with a haematological malignancy (p=0.047). There was no statistically significant association between cancer type and hospital mortality (OR 1.15 for liquid cancer p 0.58). There was also no statistically significant difference regarding intravenous fluid administration, vasopressor use, steroid use or intubation.ConclusionSolid tumour patients with sepsis or septic shock are at the same risk of mortality as patients with haematological tumours. However, haematological malignancy patients admitted with sepsis or septic shock have higher rates of bacteraemia.
Impact of parental socioeconomic status on offspring’s mental health: protocol for a longitudinal community-based study
Authors: Li Muzi , O"Donnell Kieran J , Caron Jean , D"Arcy Carl , Meng Xiangfei 
Published: February 2021

IntroductionSocioeconomic status (SES) affects physical and mental health and cognitive functioning. The association between SES changes (SES mobility) and health has ethical and political implications in that the pernicious effects of inequality and the differential impact on social classes of economic and social policies. There is a lack of research conducted to explore the intergenerational transmission of parental SES changes on the offspring’s mental health and cognitive functioning. We aim to fill this gap and identify roles of parental SES changes in offspring’s mental health and cognitive outcomes.Methods and analysisThis study will be based on a longitudinal cohort from the most populous municipality in the Canadian province of Quebec. Participants and their biological offspring will be invited to this study. For those with informed consent, we will collect their information on mental health, psychiatric disorders, cognitive functioning and early life experiences for offspring. Latent class growth analysis will be used to identify parental SES mobility groups. Multivariate regression analyses will be used to explore the roles of early life stress, parental SES mobility and their interactions in psychiatric disorders and cognitive functioning. Subgroup analyses (males and females) are also planned.Ethics and disseminationThis study has been given ethical approval by the Research Ethics Board of the Douglas Mental Health University Institute (IUSMD-18/17). Each participant will provide informed consent on participation. We will disseminate research findings through publication in peer-reviewed academic journals and presentations at conferences. Lay summaries of major research findings will also be shared annually with our partners in the health system and community agencies located in the catchment area.
Direct oral anticoagulants in treatment of cerebral venous thrombosis: a systematic review
Authors: Bose Gauruv , Graveline Justin , Yogendrakumar Vignan , Shorr Risa , Fergusson Dean A , Le Gal Gregoire , Coutinho Jonathan , Mendonça Marcelo , Viana-Baptista Miguel , Nagel Simon , Dowlatshahi Dar 
Published: February 2021

ObjectivesCurrent guidelines do not recommend direct oral anticoagulants (DOACs) to treat cerebral venous thrombosis (CVT) despite their benefits over standard therapy. We performed a systematic review to summarise the published experience of DOAC therapy in CVT.Data sourcesMEDLINE, Embase and COCHRANE databases up to 18 November 2020.Eligibility criteriaAll published articles of patients with CVT treated with DOAC were included. Studies without follow-up information were excluded.Data extraction and synthesisTwo independent reviewers screened articles and extracted data. A risk of bias analysis was performed.Primary and secondary outcome measuresSafety data included mortality, intracranial haemorrhage (ICH) or other adverse events. Efficacy data included recurrent CVT, recanalisation rates and disability by modified Rankin Scales (mRS).Results33 studies met inclusion criteria. One randomised controlled trial, 5 observational cohorts and 27 case series or studies reported 279 patients treated with DOAC for CVT: 41% dabigatran, 47% rivaroxaban, 10% apixaban and 2% edoxaban, in addition to 315 patients treated with standard therapy. The observational cohorts showed a similar risk of death in DOAC and standard therapy arms (RR 2.12, 95% CI 0.29 to 15.59). New ICH was reported in 2 (0.7%) DOAC-treated patients and recurrent CVT occurred in 4 (1.5%). A favourable mRS between 0 and 2 was reported in 94% of DOAC-treated patients, more likely than standard therapy in observational cohorts (RR 1.13, 95% CI 1.02 to 1.25).ConclusionThe evidence for DOAC use in CVT is limited although suggests sufficient safety and efficacy despite variability in timing and dose of treatment. This systematic review highlights that further rigorous trials are needed to validate these findings and to determine optimal treatment regimens.
Study protocol for a randomised controlled trial of a web-based behavioural lifestyle programme for emPOWERment in early Multiple Sclerosis (POWER@MS1)
Authors: Krause Nicole , Riemann-Lorenz Karin , Steffen Tanja , Rahn Anne Christin , Pöttgen Jana , Stellmann Jan-Patrick , Köpke Sascha , Friede Tim , Icks Andrea , Vomhof Markus , Temmes Herbert , van de Loo Markus , Gold Stefan M , Heesen Christoph 
Published: February 2021

IntroductionMultiple sclerosis (MS) is an inflammatory and degenerative disease of the central nervous system that mainly affects young adults. Uncertainty is a major psychological burden of the disease from diagnosis to prognosis, enhanced by the pressure to make early decisions on a diverse set of immunotherapies. Watchful waiting for 1–2 years while adapting goals and lifestyle habits to life with a chronic disease represents another reasonable option for persons with MS (PwMS). A behaviour change programme based on evidence-based patient information (EBPI) is not available in standard care. This randomised controlled trial (RCT) with an embedded process evaluation investigates the efficacy and cost-effectiveness of a web-based behavioural lifestyle programme to change lifestyle behaviour and reduce inflammatory disease activity in PwMS.Methods and analysisA web-based behavioural intervention will be evaluated in an RCT aiming to recruit 328 persons with clinically isolated syndrome, suspected MS or confirmed MS for less than 1 year, who have not yet started immunotherapy. Moreover, a mixed-methods process evaluation and a health economic evaluation will be carried out. Participants will be recruited in at least 16 MS centres across Germany and randomised to an intervention group with 12 months of access to EBPI about lifestyle factors in MS, combined with a complex behaviour change programme or to a control group (optimised standard care). The combined primary endpoint is the incidence of new T2 lesions on MRI or confirmed relapses.Ethics and disseminationThe study has been approved by the Ethics Committee of the Hamburg Chamber of Physicians (PV6015). Trial results will be communicated at scientific conferences and meetings and presented on relevant patient websites and in patient education seminars.Trial registration numberClinicalTrials.gov Registry (NCT03968172); Pre-results.