scholarly journals ARTICULATED CONCRETE MAT SLOPE PROTECTION

1988 ◽  
Vol 1 (21) ◽  
pp. 177 ◽  
Author(s):  
Craig B. Leidersdorf ◽  
Peter E. Gadd ◽  
William G. McDougal
Keyword(s):  
Failure Modes ◽  
Material Design ◽  
Intermediate Energy ◽  
Additional Research ◽  
Low Energy ◽  
Design Considerations ◽  
Hydraulic Design ◽  
Ice Loads ◽  
Hydraulic Stability

This paper provides guidance for the design, fabrication, and installation of articulated concrete mat slope protection. Although articulated mat armor has been utilized for many years in low-energy wave environments, it has been extended recently to accommodate intermediate wave energies and severe ice loads. The development of the concept is discussed, after which hydraulic design considerations, material design considerations, and fabrication and installation techniques are presented. Prototype performance is reviewed. It is concluded that articulated concrete mat armor is capable of providing effective slope protection in intermediate-energy wave environments, and that additional research is required relating to hydraulic stability and failure modes under wave and ice loading.

scholarly journals Fault Analysis of a Gas Turbine HTGR

1976 ◽  
Author(s):  
R. Chmielewski ◽  
K. Vepa ◽  
L. Cheng ◽  
J. Bowyer
Keyword(s):  
Gas Turbine ◽  
Failure Modes ◽  
Pressure Ratio ◽  
Power Conversion ◽  
Reactor Core ◽  
Pressure Change ◽  
Fault Analysis ◽  
Preliminary Evaluation ◽  
Design Considerations ◽  
Disk Failures

The Gas Turbine High Temperature Gas-Cooled Reactor combines a helium-cooled reactor core of established design with a closed-cycle helium turbine power-conversion system. This paper discusses the design considerations which mitigate the consequences of failure of the rotating machinery located within the reactor vessel. The methods of analysis and summary of results are presented for the failure modes of most concern. The spectrum of potential incidents which have been evaluated include turbine blade, rim, and disk failures. The requirements and design methods for rotor containment are discussed. The turbomachine maintains a pressure ratio of about two between the high and low pressure portions of the loop; postulated failures can, therefore, lead to rapid rates of pressure change. The preliminary evaluation of this internal pressure equilibration is presented.

Hydraulic design considerations for orifice spillways

2018 ◽  
Vol 25 (1) ◽  
pp. 12-18 ◽  
Author(s):  
Prajakta P. Gadge ◽  
V. Jothiprakash ◽  
V. V. Bhosekar
Keyword(s):  
Design Considerations ◽  
Hydraulic Design

Robust Reliability Assessment for Offshore Minimum Structures Under Dynamic Loads

2002 ◽  
Author(s):  
Liangbin Xu ◽  
Guoming Chen
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Dynamic Models ◽  
Research Work ◽  
Reliability Assessment ◽  
Dynamic Loads ◽  
Offshore Structure ◽  
Numeric Calculation ◽  
Ice Loads ◽  
Robust Reliability

The offshore minimum structures are widely applied in the development of margin oilfield because of their simplicity in fabrication, low initial investment and fast-track schedule. However, they would suffer large dynamic response under exciting loads such as seismic and ice loads, which might lower their service safety. The paper is focused on robust reliability assessment for the offshore minimum structures under dynamic loads by considering first-exceeding failure mode, fatigue failure mode. The robust reliability of offshore structure is a measure of its resistance to the uncertainties, and it suits very much to the condition that the information and data are scarce. The multi-level fortification for ice-resistant offshore minimum structures is presented in this paper, that is, the structure should not be defective under normal ice condition, repairable under heavy ice condition and not collapse under the heaviest ice condition. A numeric calculation method of robust reliability and several robust reliability dynamic models for offshore minimum structures are put forward in this paper, in which plastic collapse, fatigue, and fracture are dealt with. The interaction between the different failure modes under these loads is also considered in the paper. Based on research work mentioned above, the comprehensive safety assessment for the offshore minimum structures would be more easily realized under dynamic loads such as ice loads, seismic loads. Finally, the example is given.

The electronic structure and spin-charge separation of one-dimensional SrCuO2

2019 ◽  
Vol 33 (02) ◽  
pp. 1950006
Author(s):  
Huaisong Zhao ◽  
Jiasheng Qian ◽  
Sheng Xu ◽  
Feng Yuan
Keyword(s):  
Electronic Structure ◽  
Charge Separation ◽  
Energy Region ◽  
Doping Concentration ◽  
High Energy ◽  
Intermediate Energy ◽  
Low Energy ◽  
One Dimensional ◽  
High Energy Peak ◽  
Energy Peak

Based on the t-J model and slave-boson theory, we have studied the electronic structure in one-dimensional SrCuO2 by calculating the electron spectrum. Our results show that the electron spectra are mainly composed of three parts in one-dimensional SrCuO2, a sharp low-energy peak, a broad intermediate-energy peak and a high-energy peak. The sharp low-energy peak corresponds to the main band (MB) while the broad intermediate-energy peak and high-energy peak are associated with the shadow band (SB) and high-energy band (HB), respectively. From low-energy to intermediate-energy region, a clear two-peak structure (MB and SB) around the momentum [Formula: see text] appears, and the distance between two peaks decreases along the momentum direction from [Formula: see text] to [Formula: see text], then disappears at the critical momentum point [Formula: see text], leaving a single peak above [Formula: see text]. The electron spectral function in one-dimensional SrCuO2 is also the doping and temperature dependent. In particular, in the very low doping concentration, the HB merges into the MB. However, with the increases of the doping concentration, the HB separates from the MB and moves quickly to the high-binding energy region. The HB and MB are the direct results of the spin-charge separation while SB is the result of strong interaction between charge and spin parts. Therefore, our theoretical result predicts that the HB is more likely to be found at the low doping concentration, and it will be drowned in the background when the doping concentration is larger. Then with the temperature increases, the magnitude of the SB decreases, and it disappears at high temperature.

The Design, Installation, and Performance of a Berm-Supported Exploration Structure in the Beaufort Sea

1985 ◽  
Vol 107 (2) ◽  
pp. 188-194
Author(s):  
K. J. Hewitt ◽  
W. E. Berzins ◽  
J. P. Fitzpatrick ◽  
H. G. Hogeboom
Keyword(s):  
Case History ◽  
Beaufort Sea ◽  
Wave Loads ◽  
Extreme Temperatures ◽  
Related Activity ◽  
Design Considerations ◽  
Ice Conditions ◽  
Ice Loads ◽  
And Performance ◽  
Placement Technique

The design, installation, and performance of a berm-supported exploration structure in a dynamic ice environment is presented. Details are provided on design considerations which include horizontal ice loads, wave loads, seismic considerations, foundation characteristics and extreme temperatures. The development of specifications and installation techniques to account for these design concerns is presented. A case history is presented which includes a discussion of on-site modifications to the idealized placement technique, which were necessitated by extreme ice conditions. The success of this modified placement technique is confirmed through a review of the units performance during the drilling season, and the response of the structure to dynamic ice and drilling-related activity is examined.

Electronic Structures of P-Type Doped CuInS2

1996 ◽  
Vol 426 ◽  
Author(s):  
T. Yamamoto ◽  
H. Katayama-Yoshida
Keyword(s):  
Electronic Structures ◽  
Electronic Band Structure ◽  
Spherical Wave ◽  
Material Design ◽  
Electronic Band ◽  
Design Considerations ◽  
Band Structure Calculations ◽  
P Type ◽  
Structure Calculations ◽  
Codoping Method

AbstractWe have studied the electronic structures of CuIn(S0.875X0.125)2 (X=B, C, N, Si or P) based on the ab-initio electronic band structure calculations using the augmented spherical wave (ASW) method. We have clarified that the physical characteristics of the p-type doped CuInS2 crystals are mainly determined by a change in the strength of interactions between Cu and S atoms. On the basis of the calculated results, we discussed the material design considerations, such as controlling the strength of resistivity for p-type doped CulnS2 materials and converting the conduction type, from n-type to p-type by a codoping method.

Design Considerations for Ultra-Low Energy Wireless Microsensor Nodes

2005 ◽  
Vol 54 (6) ◽  
pp. 727-740 ◽  
Author(s):  
B.H. Calhoun ◽  
D.C. Daly ◽  
N. Verma ◽  
D.F. Finchelstein ◽  
D.D. Wentzloff ◽  
...  
Keyword(s):  
Low Energy ◽  
Design Considerations

Wireless Enabling Technologies for the Internet of Things

Fog Computing ◽  
2018 ◽  
pp. 54-81
Author(s):  
Mahmoud Elkhodr ◽  
Seyed Shahrestani ◽  
Hon Cheung
Keyword(s):  
Internet Of Things ◽  
Power Consumption ◽  
Network Size ◽  
Low Energy ◽  
The Internet ◽  
Wireless Technologies ◽  
Design Considerations ◽  
Ieee 802.11Ah ◽  
The Internet Of Things ◽  
Selection Of

This Chapter provides several comparable studies of some of the major evolving and enabling wireless technologies in the Internet of Things (IoT). Particularly, it focuses on the ZigBee, 6lowpan, Bluetooth Low Energy, LTE, and the different versions of Wi-Fi protocols including the IEEE 802.11ah. The studies, reported in this chapter, evaluate the capabilities and behaviors of these technologies in terms of various metrics including the data range and rate, network size, RF Channels and Bandwidth, Antenna design considerations, Power Consumption, and their Ecosystem. It is concluded that the requirements of each IoT application play a significant role in the selection of a suitable wireless technology.

A Simplified Fatigue Assessment Method for ASME VIII-2

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Jun Shen ◽  
Mingwan Lu ◽  
Heng Peng ◽  
Yinghua Liu ◽  
Zhiwei Chen
Keyword(s):  
Evaluation Method ◽  
Failure Modes ◽  
Economic Cost ◽  
Material Design ◽  
Assessment Method ◽  
Element Analysis ◽  
Design Factor ◽  
Screening Criteria ◽  
Detailed Assessment ◽  
Fatigue Evaluation

Abstract Fatigue is one of the most common and important failure modes in pressure vessel. ASME VIII-2 provides three screening criterion and three detailed assessment method for fatigue failure. With the decrease of material design factor and the extension of fatigue curve to high cycle, the applicable scope of the three screening criteria become relatively smaller and the economic efficiency is also reduced. Meanwhile, the three fatigue evaluation methods given in ASME VIII-2 Code are all based on detailed numerical calculations (such as finite element analysis (FEA)). Both economic cost and requirements of technical personnel of engineers are higher. In this paper, a simplified fatigue evaluation method is proposed, which gives simple implementation procedures and relatively conservative fatigue evaluation results. Compared with the screening criteria method A, the main advantage is that the scope of its application is wider, that is: (1) the number of significant load cycle can be considered is extended from 1000 to 105; (2) there is no upper limit to the range of pressure fluctuation, which is 20% in method A. Compared with the screening criteria method B, the main advantage is that this method is much simpler and for most materials, design fatigue curves are not required during calculation and evaluation. Compared with the three detailed assessment methods given in ASME VIII-2, this method is very convenient and does not require detailed FEA. The method proposed in this paper can simplify the evaluation process of fatigue analysis in a certain range and provide a more cost-effective engineering assessment method.

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