scholarly journals Pressure Measurement on the Surface of a Rigid Cylindrical Body During Slamming Wave Impact

2011 ◽  
Author(s):  
Diederik Van Nuffel ◽  
Sridhar Vepa ◽  
Ives De Baere ◽  
Joris Degrieck ◽  
Julien De Rouck ◽  
...  
Keyword(s):  
Experimental Data ◽  
Pressure Measurement ◽  
Water Wave ◽  
Cylindrical Body ◽  
Pressure Measurements ◽  
Large Scatter ◽  
Crucial Importance ◽  
Wave Impact ◽  
Wave Slamming ◽  
Drop Tests

Among all kinds of loads that floating and fixed marine constructions experience, water wave slamming can be considered as one of the most critical. To prevent naval constructions from failing due to slamming impact, slamming loads should be carefully investigated. Besides analytical and numerical calculations, experimental data is of crucial importance. Slamming loads can be measured by performing pressure measurements on the surface of the object during impact. Previous publications showed that precise and correct measurements are very difficult to perform, especially for slamming events with small deadrise angles. Large scatter mostly characterizes these measurements. This research focuses on improving the accuracy and reproducibility of the pressure recordings. Therefore, slamming drop tests are performed on a rigid cylindrical body. Most attention is paid to the bottom of the cylinder where the deadrise angle is 0°.

Simulation of Wave Slamming on Open-Piled Structures Based on FLUENT

2012 ◽  
Vol 256-259 ◽  
pp. 1960-1964
Author(s):  
Feng Jin
Keyword(s):  
Experimental Data ◽  
Wave Height ◽  
Impact Pressure ◽  
Two Dimensional ◽  
Numerical Wave Tank ◽  
Regular Wave ◽  
Wave Impact ◽  
Wave Tank ◽  
Wave Slamming ◽  
Numerical Wave

In order to study the specialties of wave slamming on open-piled structures, a two-dimensional regular wave tank was established based on commercial CFD software FLUENT. Three typical cases of regular wave slamming on the open-piled structures were reproduced by using the numerical wave tank and compared with the experimental data available. Good agreements were obtained between the numerical and experimental results and the average of peak impact pressure was chosen as the characteristic impact pressure. Then regular wave impact pressure on the open-piled structures under various wave height, period and over height were simulated. The influences of the three parameters on the distribution of impact pressure were analyzed.

Simulation Study on the Characteristics of Flow Field in the Process of Wave Impact

2012 ◽  
Vol 212-213 ◽  
pp. 1172-1176
Author(s):  
Jin Feng
Keyword(s):  
Experimental Data ◽  
Free Surface ◽  
Flow Field ◽  
Simulation Study ◽  
Numerical Models ◽  
Two Dimensional ◽  
Regular Wave ◽  
Wave Impact ◽  
Distribution Rule ◽  
Wave Slamming

In order to study the characteristics of flow field in the process of wave impact, two-dimensional regular wave numerical models were established based on the software FLUENT. RANS equations were adopted. The standard equations were used to close the Reynolds equations. VOF method was used to reconstruct the free surface. After three typical cases of wave slamming on open-piled structures were reproduced, the models were verified by experimental data and the flow field surrounding the structure was displayed visually. Then the processes of wave impact under various wave height, period and over height were simulated. The influences of the three parameters on the distribution of vertical velocities were analyzed, which shows that the distribution rule of the vertical velocities is similar to the wave impact pressures.

Digital manometry to measure cerebrospinal fluid pressure during lumbar puncture

2021 ◽  
pp. 197140092110551
Author(s):  
Robert Heider ◽  
Peter G Kranz ◽  
Erin Hope Weant ◽  
Linda Gray ◽  
Timothy J Amrhein
Keyword(s):  
Cerebrospinal Fluid ◽  
Lumbar Puncture ◽  
Pressure Measurement ◽  
Fluid Pressure ◽  
Cerebrospinal Fluid Pressure ◽  
Pressure Measurements ◽  
Csf Pressure ◽  
Left Lateral Decubitus Position ◽  
Significant Difference ◽  
Time Savings

Rationale and Objectives Accurate cerebrospinal fluid (CSF) pressure measurements are critical for diagnosis and treatment of pathologic processes involving the central nervous system. Measuring opening CSF pressure using an analog device takes several minutes, which can be burdensome in a busy practice. The purpose of this study was to compare accuracy of a digital pressure measurement device with analog manometry, the reference gold standard. Secondary purpose included an assessment of possible time savings. Materials and Methods This study was a retrospective, cross-sectional investigation of 71 patients who underwent image-guided lumbar puncture (LP) with opening CSF pressure measurement at a single institution from June 2019 to September 2019. Exclusion criteria were examinations without complete data for both the digital and analog measurements or without recorded needle gauge. All included LPs and CSF pressures were measured with the patient in the left lateral decubitus position, legs extended. Acquired data included (1) digital and analog CSF pressures and (2) time required to measure CSF pressure. Results A total of 56 procedures were analyzed in 55 patients. There was no significant difference in mean CSF pressures between devices: 22.5 cm H2O digitally vs 23.1 analog ( p = .7). Use of the digital manometer resulted in a time savings of 6 min (438 s analog vs 78 s digital, p < .001). Conclusion Cerebrospinal fluid pressure measurements obtained with digital manometry demonstrate comparable accuracy to the reference standard of analog manometry, with an average time savings of approximately 6 min per case.

Is It Worth $50 Million?

PEDIATRICS ◽  
1977 ◽  
Vol 59 (5) ◽  
pp. 788-789
Author(s):  
A. Frederick North
Keyword(s):  
Blood Pressure ◽  
Physical Examination ◽  
Clinical Evaluation ◽  
Pressure Measurement ◽  
Blood Pressure Measurement ◽  
Pressure Measurements ◽  
Fundoscopic Examination

Dr. Shiela Mitchell and her distinguished committee recommended in the July 1975 issue that blood pressure measurements should be a regular and routine part of every physical examination of every child over the age of 2. They recommended that any child with a blood pressure over the 95th percentile for age have a fundoscopic examination and at least one repeated blood pressure measurement and clinical evaluation within a few weeks. They stated that repeated examinations and further investigations are indicated if the blood pressure persists at or above the 95th percentile.

An Assessment of Load and Response for Horizontal Slamming Loads From Model Scale Experiments

2018 ◽  
Author(s):  
Martin Storheim ◽  
Gunnar Lian
Keyword(s):  
Structural Response ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Load Level ◽  
Material Behavior ◽  
Wave Impact ◽  
Large Variability ◽  
Slamming Load ◽  
Reasonable Approach ◽  
Wave Slamming

Steep breaking waves can result in high impact loads on offshore structures, and several model test campaigns have been conducted to assess the effect of horizontal wave slamming. High loads have been measured, and they can be challenging to withstand without significant deformation. For wave slamming problems it is common to estimate the characteristic slamming load and assume that this will give an equivalent characteristic response. One challenge related to the slamming load is that it has a large variability in load level, the duration of the load and the shape of the overall load pulse. This variability can have a large impact on the estimated response to the characteristic load, causing a similar or larger variability in response. Due to the sensitivity to the structural response, it may be difficult to interpret large amounts of such data to arrive at a relevant design load without making overly conservative assumptions. This paper investigates the sensitivity of the structural response to assumptions made in the material modelling and how the short term variability is affected if we instead of load use response indicators such as plastic strain and max deformation to arrive at a characteristic load. For this purpose, a simplified dynamic response model is created, and the recorded wave impact events can then be evaluated based on the predicted structural response from the simplified model. It was found that the structural response is sensitive to the structural configuration. The assumed material behavior and hydro-elastoplastic effects were identified to greatly affect the structural response. A reasonable approach to arrive at the q-annual response seems to be to first estimate the q-annual extreme slamming load, and then run the structural analysis on several of the measured slamming time series with the estimated q-annual extreme pressure.

Abstract P333: National Trends in the Quality of Office Blood Pressure Measurements, 2014-2019

Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Kathryn Foti ◽  
Lawrence J Appel ◽  
Kunihiro Matsushita ◽  
Josef Coresh ◽  
G Caleb Alexander ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Clinical Practice ◽  
Pressure Measurement ◽  
Blood Pressure Measurement ◽  
Pressure Measurements ◽  
Hypertension Treatment ◽  
Digit Preference ◽  
Provider Characteristics ◽  
Over Time

Introduction: Clinical practice guidelines emphasize the importance of accurate blood pressure measurement and recording to diagnose and treat hypertension. Trends in terminal digit preference (typically manifest by a terminal digit of ‘0’) have not been examined nationally. The growing use of automated blood pressure devices may have reduced terminal digit preference and improved accuracy over time. Objective: To evaluate trends in terminal digit preference in office blood pressure measurements among adults with hypertension by patient and provider characteristics. Methods: We used IQVIA National Disease and Therapeutic Index (NDTI) data from January 2014 through June 2019. The NDTI is designed to be nationally-representative of all patient visits to office-based physicians and uses a two-stage stratified sampling design to sample ~4,000 physicians per quarter who report information on all patient visits on 2 random workdays. We included all hypertension treatment visits (~60M/year) among adults aged ≥18. We examined trends in the proportion of hypertension treatment visits with recorded systolic (SBP) and diastolic (DBP) blood pressure measurements with a terminal digit ‘0’. The expected percent of blood pressures with ‘0’ is 10% for automated and 20% for manual readings. Results: There was a decrease in the percent of visits with SBP (43.0% to 37.4%) or DBP (44.3% to 38.1%) recordings ending in zero ( Table ). The decrease in percent of SBPs with a terminal zero was similar by patient and provider characteristics, though the percentage of SBPs with a terminal ‘0’ was consistently higher among patients aged ≥60, when SBP ≥140 mmHg, and among cardiologists. Conclusions: Terminal digit preference is common indicating systematic error in blood pressure measurement and recording, despite some improvement over time. This may lead to under- and overtreatment of patients with hypertension. Improving the quality of blood pressure measurement is central to improving hypertension diagnosis and control in clinical practice.

Measuring Blood Pressure

Nursing OSCEs ◽  
2012 ◽  
Author(s):  
Kate Devis
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Pressure Measurement ◽  
Gold Standard ◽  
Blood Pressure Measurement ◽  
Maximum Pressure ◽  
Pressure Measurements ◽  
Health Care Settings ◽  
Pressure Cuff ◽  
The Uk

Blood pressure measurements are one part of a circulatory assessment (Docherty and McCallum 2009). Treatments for raised or low blood pressure may be initiated or altered according to blood pressure readings; therefore correct measurement and interpretation of blood pressure is an important nursing skill. Blood pressure should be determined using a standardized technique in order to avoid discrepancies in measurement (Torrance and Serginson 1996). Both manual and automated sphygmomanometers may be used to monitor blood pressure. The manual auscultatory method of taking blood pressure is considered the gold standard (MRHA 2006), as automated monitoring can give false readings (Coe and Houghton 2002), and automated devices produced by different manufacturers may not give consistent figures (MRHA 2006). So, although automated sphygmomanometers are in common use within health care settings in the UK, the skill of taking blood pressure measurement manually is still required by nurses. As a fundamental nursing skill, blood pressure measurement, using manual and automated sphygmomanometers, and interpretation of findings are often assessed via an OSCE. Within this chapter revision of key areas will allow you to prepare thoroughly for your OSCE, in terms of practical skill and understanding of the procedure of taking blood pressure. Blood pressure is defined as the force exerted by blood against the walls of the vessels in which it is contained (Docherty and McCallum 2009). A blood pressure measurement uses two figures—the systolic and diastolic readings. The systolic reading is always the higher figure and represents the maximum pressure of blood against the artery wall during ventricular contraction. The diastolic reading represents the minimum pressure of the blood against the wall of the artery between ventricular contractions (Doughetry and Lister 2008). You will need to be able to accurately identify systolic and diastolic measurements during your OSCE. When a blood pressure cuff is applied to the upper arm and inflated above the level of systolic blood pressure no sounds will be detected when listening to the brachial artery with a stethoscope. The cuff clamps off blood supply. As the cuff is deflated a noise, which is usually a tapping sound, will be heard as the pressure equals the systolic blood pressure —this is the first Korotkoff ’s sound.

6114Indications, procedural parameters, complications and consequences of fractional flow reserve measurements in a multicenter cohort

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
M Troebs ◽  
M Marwan ◽  
L Gaede ◽  
J Feyrer ◽  
B Nazli ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Fractional Flow Reserve ◽  
Pressure Measurement ◽  
Patient Characteristics ◽  
Pressure Measurements ◽  
Fractional Flow ◽  
Coronary Syndrome ◽  
Flow Reserve ◽  
Adenosine Administration ◽  
Vessel Dissection

Abstract Background Determination of the Fractional Flow Reserve (FFR) has become part of routine clinical practice. Contemporary clinical use, consequences as well as complications in consecutive, large cohorts have not been thoroughly investigated. We report the results of the prospective Fractional Flow Reserve Fax Registry F (FR2) conducted in Germany. Purpose To systematically analyze indications, procedural parameters, complications and consequences of intracoronary pressure measurements in a large contemporary cohort. Methods Data of 2000 consecutive patients undergoing clinically indicated FFR, iFR or pd/pa measurements in 8 interventional centres in Germany were prospectively collected in a systematic fashion. Data included basic patient characteristics, procedural aspects of intracoronary pressure measurements, associated complications, visual stenosis degree, measurement results and treatment decisions. Results Mean patient age was 68±11 years, 73% of patients were male. Of all patients, 300 patients (15%) had an acute coronary syndrome (STEMI: 9; NSTEMI: 94; unstable angina: 197) and 1002 patients (50%) had undergone previous revascularization. A mean of 1.7±0.9 measurements were performed per patient, for which an average of 1.02 pressure wires were required (more than 1 wire in 64 patients). For all 3373 interrogated lesions, median stenosis degree was 60%. Vasodilator-free measurements were performed in 415/3373 cases (12%, iFR: 346; pd/pa: 69). For vasodilation, i.v. adenosine was used in 396 cases (13%), i.c. adenosine in 2628 cases (87%), and other drugs in 10 cases (0.3%). Measurement was performed before potential revascularization in 3232 cases (96%) and during or following PCI in 141 cases. In 2958 lesions analyzed by FFR, mean FFR was 0.87, with 588 FFR measurements ≤0.80 (19.8%). Median FFR values were higher for i.c than i.v. adenosine administration (0.88 vs. 0.84), but not significantly different after adjustment for stenosis degree. In 735 cases (20.2%), intracoronary pressure measurement was followed by revascularization measures, while in 2637 cases (79.8%), no revascularization or no further revascularization was performed. In 36 out of 117 stenoses visually estimated to be ≥90%, revascularization was deferred following pressure measurement (31%). In 75 out of 2958 lesions analyzed by FFR, revascularization was performed even though FFR was >0.80 (3%). Severe complications (vessel dissection or occlusion) occurred in 5 out of 2000 patients as a consequence of intracoronary pressure measurement, resulting in death of 1 patient. Conclusion In clinical practice, the majority of intracoronary pressure measurements are performed in stenoses of intermediate angiographic severity and revascularization is deferred in approximately 80% of lesions. Vasodilator-free measurements are infrequent and route of adenosine administration has no effect on results. Complication rate is low but not negligible. Acknowledgement/Funding Abbott Vascular

Unsteady Aerodynamics and Interactions Between a High Pressure Turbine Vane and Rotor

2004 ◽  
Author(s):  
Ryan M. Urbassik ◽  
J. Mitch Wolff ◽  
Marc D. Polanka
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Potential Field ◽  
Rotor Blade ◽  
Second Harmonic ◽  
Unsteady Aerodynamics ◽  
Pressure Measurements ◽  
High Pressure Turbine ◽  
Turbine Vane ◽  
Unsteady Pressure Measurements

A set of experimental data is presented investigating the unsteady aerodynamics associated with a high pressure turbine vane (HPV) and rotor blade (HPB). The data was acquired at the Turbine Research Facility (TRF) of the Air Force Research Laboratory. The TRF is a transient, blowdown facility generating several seconds of experimental data on full scale engine hardware at scaled turbine operating conditions simulating an actual engine environment. The pressure ratio and freestream Reynolds number were varied for this investigation. Surface unsteady pressure measurements on the HPV, total pressure traverse measurements downstream of the vane, and surface unsteady pressure measurements for the rotor blade were obtained. The unsteady content of the HPV surface was generated by the rotor potential field. The first harmonic decayed more rapidly than the second harmonic with a movement upstream causing the second harmonic to be most influential at the vane throat. The blade unsteadiness appears to be caused by a combination of shock, potential field, and vane wake interactions between the vane and rotor blade. The revolution averaged data resulted in higher unsteadiness than a passing ensemble average for both vane and rotor indicating a need to understand each passage for high cycle fatigue (HCF) effects.

Laboratory Observations on the Evolution of Deep-Water Wave Packets

2011 ◽  
Author(s):  
Yuxiang Ma ◽  
Guohai Dong ◽  
Xiaozhou Ma
Keyword(s):  
Experimental Data ◽  
Deep Water ◽  
Wave Breaking ◽  
Water Wave ◽  
Wave Packets ◽  
Local Maximum ◽  
Peak Frequency ◽  
Higher Harmonics ◽  
Stokes Waves ◽  
Deep Water Wave

New experimental data for the evolution of deep-water wave packets has been presented. The present experimental data shows that the local maximum steepness for extreme waves is significantly above the criterion of the limiting Stokes waves. The wavelet spectra of the wave groups around the breaking locations indicate that the energy of higher harmonics can be generated quickly before wave breaking and mainly concentrate at the part of the wave fronts. After wave breaking, however, these higher harmonics energy is dissipated immediately. Furthermore, the variations of local peak frequency have also been examined. It is found that frequency downshift increases with the increase of initial steepness and wave packet size.

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