minimum pressure
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2021 ◽  
Vol 21 (5) ◽  
pp. 251-261
Author(s):  
Taegyun Kim

For preparing damage from typhoons, the new typhoon rating system was developed that can predict the magnitude of damage by using the maximum wind speed and rainfall for duration 3 hrs at a specific location along the track. Existing forecasts predict typhoon’s characteristic values such as tack, minimum pressure, maximum wind speed and radiis, and issue typhoon advisories and typhoon warnings when danger or damage is expected. However, as it is difficult to prepare a response using this information alone, I developed new typhoon ratings that took the typhoon damage scale into account to aid disaster preparation. I divided typhoon grades into four classes based on the magnitude of damage. The grades were determined based on the maximum wind speed at a point near the 33° north latitude and rainfall for duration 3 hrs from the time at that point.


Author(s):  
Xingtao Wang ◽  
Jian Zhang ◽  
Sheng Chen ◽  
Lin Shi ◽  
Wenlong Zhao ◽  
...  

Abstract In order to guarantee the safety of pumps, valves are installed at the outlet of each pump in long-distance pressurized water supply systems. However, water hammer pressure caused by improper valve closure can tremendously exceed the standard of the pipeline. In this paper, the effects of valve closure on speed of pump and pressure along the pipeline were investigated. Valve closure formula based on pump runaway characteristics were proposed and verified using numerical simulation. In addition, when valves were closed under the formula proposed in this paper and other closure laws, the minimum speed, minimum and maximum pressure along the pipeline were compared. The results showed that formulas agree well with the numerical results. In the high lift supply systems, compared with the other closure laws, the minimum speed and minimum pressure along the pipeline under valve closure formula were the largest, and the maximum pressure along the pipeline was the smallest. Moreover, in the low lift supply systems, the minimum speed under valve closure formula did not exceed the rated speed. Compared with the other closure laws, the minimum pressure along the pipeline was the largest and the maximum pressure along the pipeline was the smallest.


Icarus ◽  
2021 ◽  
Vol 356 ◽  
pp. 114070
Author(s):  
Perianne E. Johnson ◽  
Leslie A. Young ◽  
Silvia Protopapa ◽  
Bernard Schmitt ◽  
Leila R. Gabasova ◽  
...  
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Author(s):  
M. Fiatt ◽  
A.C. Bosio ◽  
D. Neves ◽  
R. Symanski da Cunha ◽  
L.T. Fonseca ◽  
...  

BACKGROUND: Prevalence of extubation failure in neonates may be up to 80%, but evidence to determine if a neonate is ready for extubation remains unclear. We aim to evaluate a spontaneous breathing trial accuracy with minimum pressure support to predict success in neonates’ extubation and identify variables related to failures. METHODS: This is a diagnostic accuracy study based on a cohort study in an intensive care unit with all eligible newborn infants subjected to invasive mechanical ventilation for at least 24 hours submitted to the trial for 10 minutes before extubations. The outcome was failures of extubations, considered if reintubation was needed until 72 hours. RESULTS: The incidence of failure was 14.7%among 170 extubations. There were 145 successful extubations; of these, 140 also passed the trial with a sensitivity of 96.5%(95%CI: 92.1–98.9). Of the 25 extubations that eventually failed, 16 failed the test with a specificity of 64.0%(95%CI: 42.5–82.0). The negative predictive value was 76.2%, and the positive predictive value was 94%. In stratifying by weight, the accuracy was >98.7%for neonates weighting >2500 g, but 72.5%for those weighing <1250 g. Extubation failures occurred more frequently in smaller (p = 0.01), preterm infants (p = 0.17), with longer ventilation time (p = 0.05), and having a hemodynamically significant persistent arterial duct (p = 0.01), compared with infants whose extubation was successful. CONCLUSION: The spontaneous breathing trial with minimum pressure support ventilation seems to predict extubation success with great accuracy in full-term and larger neonates.


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6347
Author(s):  
Junhong Hao ◽  
Youjun Zhang ◽  
Nian Xiong

Integration of modeling and optimization of a thermal management system simultaneously depends on heat transfer performance of the components and the topological characteristics of the system. This paper introduces a heat current method to construct the overall heat current layout of a typical double-loop thermal management system. We deduce the system heat transfer matrix as the whole system constraint based on the overall heat current layout. Moreover, we consider the influences of structural and operational parameters on the thermal hydraulic performances of each heat exchanger by combining the empirical correlations of the heat transfer and pressure drop. Finally, the minimum pressure drop is obtained by solving these optimal governing equations derived by the Lagrange multiplier method considering the physical constraints and operational conditions. The optimization results show that the minimum pressure drop reduces about 8.1% with the optimal allocation of mass flow rates of each fluid. Moreover, the impact analyses of structural and operating parameters and boundary conditions on the minimum and optimal allocation present that the combined empirical correlation-heat current method is feasible and significant for achieving integrated component-system modeling and optimization.


2020 ◽  
Vol 34 (15) ◽  
pp. 5047-5059
Author(s):  
P. Sivakumar ◽  
Nikolai B. Gorev ◽  
Rajesh Gupta ◽  
Tiku T. Tanyimboh ◽  
Inna F. Kodzhespirova ◽  
...  

2020 ◽  
Vol 87 (10) ◽  
pp. 630-636
Author(s):  
Oliver Slanina ◽  
Susanne Quabis ◽  
Robert Wynands

AbstractTo ensure the safety of users like hunters and sports shooters, the dynamic pressure inside an ammunition cartridge must not exceed a maximum value. We have investigated the reproducibility of the dynamic measurement of the gas pressure inside civilian ammunition cartridges during firing, when following the rules formulated by the Permanent International Commission for the Proof of Small Arms (C. I. P.). We find an in-house spread of 0.8 % between maximum and minimum pressure for runs with the same barrel and of 1.8 % among a set of three barrels. This sets a baseline for the expected agreement in measurement comparisons between different laboratories. Furthermore, a difference of more than 3 % is found in a preliminary study of the influence of ammunition storage conditions.


Author(s):  
Chunqiang Zhang ◽  
Xiaomin Ji ◽  
Yanmin Xue ◽  
Gang Hu

Ankles can benefit from the elastic tube bandage (ETB) by providing the ankle joint with compression, but partial high- or low-pressure leads to body discomfort. The aim of this paper is to propose a method for analyzing the ankle shape with the fabric compression which is basis on the comfortable pressure on human body. First, a standard model of ankle is established from the scanned data of 306 samples, and the mapping of the fabric shape curves on ankle were constructed by the U-direction convex curves of the model. The positions or areas of maximum and minimum pressure are then marked by extracting the curvatures of the fabric shape curves. According to the Laplace’s Law, the sizes of ETBs can be calculated given that the value of comfortable pressure on human body is the maximum one. The data of calculation is approximate to the relevant previous studies which has the same parameters of ETBs. Nine groups of the ankle shapes from the database are discussed, each group has a proportional coefficient to the standard model, and the result shows that six sizes of ETBs with comfort pressure match for the nine groups. These can be applied to the comfort design, and the method proposed can boost size customization of ETBs, as well as will inspire the research on other elastic compression garments.


Author(s):  
Teguh Taruna Utama

Drinking water sources in Manggarai Regency are mostly supplied from springs. Golo Wua and Golo Watu are two villages in Manggarai Regency that utilize springs. About 12.06 liters/second of drinking water are needed by residants in those villages. This study addresses to forecast the demand of drinking water. This study found that pressure values in manual calculations range from 1.85 meters to 84.22 meters. The minimum pressure requirements from BPP-SPAM is 7 meters (0.7 bar). While the simulation results using the EPANET program, the pressure value is at 1.90 meters up to 84.22 meters. Therefore, the pipe diameter selection is appropriate and the pressure meets the requirements of the BPP-SPAM. Difference between pressure values less than 5% indicates that the selection is the right pipe diameter. Choosing the right pipe diameter will optimize the distribution network in the villages of Golo Wua and Golo Watu. The selected pipe is HDPE type. Selected pipe diameter 1½"; 2"; 2½”; 3"; 4 and 5". The pipe has a pressure resistance of up to 125 meters.


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