Sustained Stress Indices (SSI) in the B31.3 2010 Edition

2014 ◽  
Author(s):  
Charles Becht ◽  
Tony Paulin ◽  
Don Edwards ◽  
Mark Stonehouse ◽  
William Santiago Lock ◽  
...  
Keyword(s):  
Test Procedure ◽  
Stress Index ◽  
Stress Indices ◽  
Time Stress ◽  
Flexibility Factor

The 2010 version of B31.3 introduced sustained stress indices (SSI’s) in paragraph 320. Using methods in references [1],[2],[3],[4],[5], and [11], a test procedure was developed to evaluate these SSI’s for standard metallic piping components. The test procedure has been incorporated into draft versions of B31J so that the sustained stress index can be produced at the same time stress intensification or flexibility factor tests are performed for a particular component. This paper describes the sustained stress index and the B31J test procedure used to determine the SSI.

Very thin torispherical pressure vessel ends under internal pressure: Test procedure and typical results

1981 ◽  
Vol 16 (3) ◽  
pp. 171-186 ◽  
Author(s):  
P Stanley ◽  
T D Campbell
Keyword(s):  
Stainless Steel ◽  
Internal Pressure ◽  
Elastic Stress ◽  
Test Procedure ◽  
Pressure Vessels ◽  
Time Dependent ◽  
Test Installation ◽  
Stress Indices ◽  
Pressure Test ◽  
Strain Data

Very thin cylindrical pressure vessels with torispherical end-closures have been tested under internal pressure until buckles developed in the knuckles of the ends. These were prototype vessels in an austenitic stainless steel. The preparation of the ends and the closed test vessels is outlined, and the instrumentation, test installation, and test procedure are described. Results are given and discussed for three typical ends (diameters 54, 81, and 108in.; thickness to diameter ratios 0.00237, 0.00158, and 0.00119). These include measured thickness and curvature distributions, strain data and the derived elastic stress indices, and pole deflection measurements. Some details of the observed time-dependent plasticity (or ‘cold creep’) are given. Details of two types of buckle that developed eventually in the vessel ends are also reported.

scholarly journals Water stress indices for the sugarcane crop on different irrigated surfaces

2016 ◽  
Vol 20 (10) ◽  
pp. 925-929 ◽  
Author(s):  
Rodrigo G. Brunini ◽  
José E. P. Turco
Keyword(s):  
Water Stress ◽  
Raw Materials ◽  
Irrigation System ◽  
Canopy Temperature ◽  
Ambient Air ◽  
Saccharum Officinarum ◽  
Stress Index ◽  
Stress Indices ◽  
Sugarcane Crop ◽  
Water Stress Index

ABSTRACT Sugarcane (Saccharum officinarum L.) is a crop of vital importance to Brazil, in the production of sugar and ethanol, power generation and raw materials for various purposes. Strategic information such as topography and canopy temperature can provide management technologies accessible to farmers. The objective of this study was to determine water stress indices for sugarcane in irrigated areas, with different exposures and slopes. The daily water stress index of the plants and the water potential in the soil were evaluated and the production system was analyzed. The experiment was carried out in an “Experimental Watershed”, using six surfaces, two horizontal and the other ones with 20 and 40% North and South exposure slopes. Water stress level was determined by measuring the temperatures of the vegetation cover and the ambient air. Watering was carried out using a drip irrigation system. The results showed that water stress index of sugarcane varies according to exposure and slope of the terrain, while areas whose water stress index was above 5.0 oC had lower yield values.

Evaluating financial stress indicators: evidence from Indian data

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sruti Mundra ◽  
Motilal Bicchal
Keyword(s):  
Financial Crisis ◽  
Business Cycle ◽  
Financial Stress ◽  
Stress Index ◽  
Stress Indicators ◽  
Content Type ◽  
Stress Indices ◽  
Macroeconomic Effect ◽  
The Business Cycle ◽  
Systemic Stress

Purpose The purpose of this study is to assess alternative financial stress indicators for India in terms of tracing crisis events, mapping with the business cycle and the macroeconomic effect of stress indices. Design/methodology/approach The study constructs the composite indicator of systemic stress of Hollo, Kremer and Lo Duca (2012) for India using two different methods for computing time-varying cross-correlation matrix, namely, exponentially weighted moving average (EWMA) and dynamic conditional correlation-generalized autoregressive conditional heteroscedasticity (DCC-GARCH). The derived indices are evaluated with widely used, equal variance and principal component weighting indices in terms of tracing stress events, mapping with the business cycles and the macroeconomic effect. For this purpose, the study identifies various episodes of financial stress and uses the business cycle dates in the sample covering from January 2001 to October 2018. Findings The results suggest that stress indices based on EWMA and DCC-GARCH accurately identify the well-known stress periods and capture the recession dates and show an adverse effect on economic activity. Primarily, the DCC-GARCH-based stress index emerges as a better indicator of stress because it efficiently locates all the major-minor events, traces the build-up of stress and reverts to the normal level during stable times. Practical implications The DCC-GARCH-based stress index is a very useful indicator for policymakers in regularly monitoring India’s financial conditions and providing timely identification of systemic stress to avoid adverse repercussion effects of the financial crisis. Originality/value The 2007–2008 financial crisis and subsequent recurrent instability in the financial markets highlighted the requirement for an appropriate financial stress indicator for a timely assessment of the system-wide financial stress. To the authors’ knowledge, this is the first study that incorporates the systemic nature of financial stress in the construction of stress indices for India and provides a holistic evaluation of the financial stress from an emerging country’s perspective.

Assessing canopy temperature-based water stress indices for soybeans under subhumid conditions

2020 ◽  
Author(s):  
Angela Morales Santos ◽  
Reinhard Nolz
Keyword(s):  
Water Stress ◽  
Soil Water ◽  
Water Status ◽  
Canopy Temperature ◽  
Irrigation Scheduling ◽  
Stress Index ◽  
Crop Water ◽  
Stress Indices ◽  
Soil Water Status ◽  
Crop Water Stress

<p>Sustainable irrigation water management is expected to accurately meet crop water requirements in order to avoid stress and, consequently, yield reduction, and at the same time avoid losses of water and nutrients due to deep percolation and leaching. Sensors to monitor soil water status and plant water status (in terms of canopy temperature) can help planning irrigation with respect to time and amounts accordingly. The presented study aimed at quantifying and comparing crop water stress of soybeans irrigated by means of different irrigation systems under subhumid conditions.</p><p>The study site was located in Obersiebenbrunn, Lower Austria, about 30 km east of Vienna. The region is characterized by a mean temperature of 10.5°C with increasing trend due to climate change and mean annual precipitation of 550 mm. The investigations covered the vegetation period of soybean in 2018, from planting in April to harvest in September. Measurement data included precipitation, air temperature, relative humidity and wind velocity. The experimental field of 120x120 m<sup>2</sup> has been divided into four sub-areas: a plot of 14x120 m<sup>2</sup> with drip irrigation (DI), 14x120 m<sup>2</sup> without irrigation (NI), 36x120 m<sup>2</sup> with sprinkler irrigation (SI), and 56x120 m<sup>2</sup> irrigated with a hose reel boom with nozzles (BI). A total of 128, 187 and 114 mm of water were applied in three irrigation events in the plots DI, SI and BI, respectively. Soil water content was monitored in 10 cm depth (HydraProbe, Stevens Water) and matric potential was monitored in 20, 40 and 60 cm depth (Watermark, Irrometer). Canopy temperature was measured every 15 minutes using infrared thermometers (IRT; SI-411, Apogee Instruments). The IRTs were installed with an inclination of 45° at 1.8 m height above ground. Canopy temperature-based water stress indices for irrigation scheduling have been successfully applied in arid environments, but their use is limited in humid areas due to low vapor pressure deficit (VPD). To quantify stress in our study, the Crop Water Stress Index (CWSI) was calculated for each plot and compared to the index resulting from the Degrees Above Canopy Threshold (DACT) method. Unlike the CWSI, the DACT method does not consider VPD to provide a stress index nor requires clear sky conditions. The purpose of the comparison was to revise an alternative method to the CWSI that can be applied in a humid environment.</p><p>CWSI behaved similar for the four sub-areas. As expected, CWSI ≥ 1 during dry periods (representing severe stress) and it decreased considerably after precipitation or irrigation (representing no stress). The plot with overall lower stress was BI, producing the highest yield of the four plots. Results show that DACT may be a more suitable index since all it requires is canopy temperature values and has strong relationship with soil water measurements. Nevertheless, attention must be paid when defining canopy temperature thresholds. Further investigations include the development and test of a decision support system for irrigation scheduling combining both, plant-based and soil water status indicators for water use efficiency analysis.</p>

B2' Stress Indices for Elbows Using Non-Linear Finite Element Analysis

2004 ◽  
Author(s):  
K. Venkataramana ◽  
V. Bhasin ◽  
K. K. Vaze ◽  
H. S. Kushwaha
Keyword(s):  
Plastic Deformation ◽  
Finite Element ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Power Plants ◽  
Kinematic Hardening ◽  
Material Behavior ◽  
Stress Index ◽  
Stress Indices

Nuclear power plants are designed to withstand earthquake loads without severe damage under service level D conditions. Under earthquake induced reversing dynamic load, nuclear power plant components may undergo plastic deformation. Plastic deformation in class I nuclear power plant piping systems is limited by Equation (9) of ASME Boiler & Pressure Vessel Code [14], Section III, NB-3652. In the year 2000, the ASME B&PV Code was revised to accommodate reversing dynamic loading in which the failure mode is fatigue ratcheting, instead of plastic collapse. This modified equation [16] contains B2′ index, which is given as a fraction of B2 index where, B2 is defined for monotonic loading [17]. In this study a new definition is proposed for calculating B2′ stress index which is given by B2′ = MCLcyclicRange,straightpipe/MCLcyclicRange,component, where MClcyclicRange is the range of collapse moment. Incremental elastic-plastic nonlinear finite element analyses are performed considering both material and geometric nonlinearities. Kinematic hardening, isotropic hardening and elastic-perfectly plastic material models have been used to model the material behavior during plastic deformation. Load deflection curves are obtained and from these curves collapse loads for monotonic and cyclic loading are determined. B2 and B2′ stress indices are computed for elbows using the proposed equation. The computed stress indices are compared with ASME Code values.

Abstract 12880: A Clinical Index of Myocardial Afterload Can Replace Wall Stress Calculations

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Nathaniel Reichek ◽  
Jonathan Weber ◽  
Madhavi Kadiyala ◽  
Marie Grgas ◽  
Tazim Merchant ◽  
...  
Keyword(s):  
Treatment Guidelines ◽  
Systolic Pressure ◽  
Wall Stress ◽  
Stress Index ◽  
Stress Indices ◽  
Lv Volume ◽  
And Gender ◽  
Brachial Systolic Pressure ◽  
Myocardial Level

Introduction: Afterload at the myocardial level is a principal determinant of LV chamber and myocardial wall function, generated by interplay of LV pressure, volume, and mass. Quantitation has relied on wall stress indices which require additional measurements and calculations as well as incorrect assumptions. Unfamiliar to most clinicians, they have largely fallen out of use, but the role of myocardial afterload in contemporary heart failure pathophysiology and therapy merits reevaluation given the roles of EF and myocardial strains in prognostic indices and treatment guidelines. Hypothesis: A simple clinical afterload index using variables fundamental to wall stress indices (systolic pressure(mmHg) * LV volume(ml))/LV mass(g)) or PV/M correlates closely with stress indices and relates similarly to LV EF and myocardial strains. Methods: In 277 normals (54% female, mean age 50.9±12.9 yrs) and small cohorts with dilated non-ischemic cardiomyopathy(35), aortic stenosis(12) and cancer chemotherapy(43), each with matched controls, we used CMR LV volumes, mass and brachial systolic pressure during imaging to compare end-systolic PV/M to stress indices and systolic pressure alone using correlations and correlation standard errors(SEs). Results: There were extremely close correlations (r= 0.97-0.99, all p< 0.001) with minimal SEs between PV/M and Arts and Alters stress indices with similar slopes in all groups and in normal subgroups by age and gender. Negative correlations with EF, global strains and strain rates were also present and extremely similar in all groups. But Mirsky’s stress index and brachial pressure performed less well. Conclusions: A simple clinical afterload index correlates closely with wall stress indices and similarly with LV ejection fraction and strains. It can support efficient reassessment of the role of afterload at the myocardial level in research and potentially, in clinical practice.

Stress Analysis and Stress Index Development for a Trunnion Pipe Support

1982 ◽  
Vol 104 (2) ◽  
pp. 73-78
Author(s):  
M. H. Sadd ◽  
R. R. Avent
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Stress Analysis ◽  
Wall Thickness ◽  
Pressure Vessel ◽  
Stress Index ◽  
Secondary Stress ◽  
Empirical Formulas ◽  
Stress Indices ◽  
Finite Element Stress Analysis

A finite element stress analysis is presented of a trunnion pipe anchor. The structure is analyzed for the case of internal pressure and various end moment loadings. Stress results were post-processed and decomposed into average and linear varying (through the wall thickness). These decomposed values were then interpreted within the ASME Boiler and Pressure Vessel Code to estimate primary and secondary stress indices. Several computer runs were made for a variety of structural sizes and empirical formulas were developed expressing the stress indices as a function of certain dimensionless ratios.

Stress Index Development for Special Elbows

2009 ◽  
Author(s):  
J.-M. Kim ◽  
H.-C. Song ◽  
S.-Y. Kang ◽  
S.-H. Park ◽  
J.-S. Yang ◽  
...  
Keyword(s):  
Finite Element ◽  
The Other ◽  
Stress Index ◽  
Piping System ◽  
Element Analysis ◽  
Finite Element Program ◽  
Stress Indices ◽  
Reactor Coolant ◽  
Class 1 ◽  
Asme Code

The reactor coolant piping system is designed to be in compliance with the requirements of Class 1 piping of Section III of the ASME Boiler and Pressure Vessel Code. Stress indices are required to evaluate the nuclear Class 1 piping. The reactor coolant system of Kori 1 nuclear power plant consists of a 2-loop system, each having two special elbows: one is the reducing elbow with a non-uniform thickness, and the other is the elbow with a splitter installed inside the elbow. However, stress indices for special elbows are not specified in NB-3683.7 of the ASME Code. In this paper, we computed the stress indices of special elbows for pressure and moment loads by the finite element analysis. The linear elastic method was used for the analysis with the finite element program, ANSYS, and the solid element (SOLID 45) was selected to model the geometry. The finite element model of the special elbows included a straight segment of pipe on each end of the elbows. The uniformly distributed internal pressure was applied to the pipe and elbow. The equivalent axial blow-off load was applied to one end, and the translational degree of freedom was fixed at the other end of the model. The moment was applied to one end, and the boundary condition was fixed at the other end of the model. Based on the analysis results, it is concluded that stress indices, except B1, in NB-3683.7 of the ASME Code can be used for special elbows conservatively. More analyses are required to apply B1 index to the special elbows.

scholarly journals The Impact of Economic Instability on the Development of the European Tourism Market

2021 ◽  
Vol 102 (2) ◽  
pp. 75-88
Author(s):  
Anton Ovcharov ◽  
◽  
Marina Malkina ◽  
Keyword(s):  
Principal Component ◽  
Arithmetic Mean ◽  
Tourism Industry ◽  
High Rate ◽  
Stress Index ◽  
Stress Indices ◽  
Economic Instability ◽  
Steady Growth ◽  
The Impact ◽  
Overnight Stays

The paper studies modern trends and factors of instability in the European tourism market. Using the methods of statistical analysis, the authors explored the impact of crises on the dynamics of the tourism market indicators. The low but steady growth rate of the tourism industry in European countries over two decades was only once disrupted by the global economic crisis of 2008-2009. Until 2020 the European tourism has been showing good adaptability to instability factors and a high rate of abilities to recover from crises. The 2020 crisis has given rise to the worst external shock to the European tourism market in its history. Using two methods (arithmetic mean of normalized partial stress indices and principal component analysis), an integral stress index for the tourism industry were constructed, allowing to identify the onset of economic instability for the tourism industry. This index was composed of such private indicators as tourist arrivals, overnight stays, occupancy and tourism turnover, and calculated for four EU countries (Italy, Spain, Germany and Finland). Based on its dynamics, we identified the periods of increasing stress for each country’s tourism market and made conclusions about a significant correlation of tourism stress indices of the countries under consideration.

B 2 and C2 Stress Indices for Large-Angle Bends

2002 ◽  
Vol 124 (2) ◽  
pp. 177-186 ◽  
Author(s):  
Rajnish Kumar ◽  
M. A. Saleem
Keyword(s):  
Large Angle ◽  
Stress Index ◽  
Bend Angle ◽  
Maximum Increase ◽  
Worst Case ◽  
Stress Indices ◽  
Maximum Value ◽  
Asme Code ◽  
The Moment ◽  
Bend Angles

B 2 and C2 stress indices are needed for evaluation of nuclear piping components. These indices are used in calculation of stress terms corresponding to moment loading. The formulas (B2=1.3/h2/3 and C2=1.95/h2/3) given in the ASME Boiler and Pressure Vessel Code for calculating these stress indices for elbows and bends are independent of bend angle. Author’s earlier work indicated that the values obtained by these formulas are conservative for bend angle ⩽90 deg. The objective of the present study was to investigate the values of B2 and C2 stress indices for elbows with bend angles larger than 90 deg and to evaluate the limit of the applicability of the ASME Code formulas in terms of the bend angle. For this purpose, elbows with bend angles ranging from 90 to 180 deg have been investigated in detail. Elbow sizes studied ranged from 2.5 to 20 NPS. Finite element models have been used for detailed analysis. To cover the worst case of stresses in the elbows, several hundred load cases were analyzed by varying the direction of the moment loading. It was found that the three independent loading cases corresponding to three orthogonal axes do not bound the worst-case stress in the elbows. The results of the analysis show that the calculated value of B2 stress index increases with bend angle; but its value, even for 180-deg bend angle, remains below the ASME Code value with a margin of at least 15%. Considering all analyzed elbows and bend angles from 90 to 180 deg, the calculated maximum value of C2 stress index is found to be within 2 percent of the ASME Code value. The maximum increase in the value of B2 stress index is 12.5 percent as the bend angle is increased from 90 to 180 deg. The corresponding increase in the C2 stress index is less than 8%. Based on these results and authors’ earlier work, a modification to ASME Code formulas is proposed for calculation of more realistic values of the stress indices for bends up to 180 deg.

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