Recognizing HPC Workloads Based on Power Draw Signatures

Author(s):  
Sven Kohler ◽  
Lukas Wenzel ◽  
Max Plauth ◽  
Pawel Boning ◽  
Philipp Gampe ◽  
...  
Keyword(s):  
2014 ◽  
Vol 67 (3) ◽  
pp. 311-316
Author(s):  
Eduardo Nozawa Caetano de Araujo ◽  
Homero Delboni Jr.

Tumbling mills are often taken as the object of optimization studies because they are a type of equipment that consume large amounts of energy. Among the current available resources to conduct such studies, mathematic modelling presents great efficiency due to its low cost, speed and reliability. The total charge and grinding media charge are very important variables to conduct modelling exercises that aim at power draw and product size distribution forecasting. However, the common measurement methods require people entering the equipment, which carries a number of adversities related to confined spaces. In this regard, this paper presents the development of a method and the prototype of a device able to measure tumbling mill charges, quickly, precisely, with low cost and, above all, ensuring safety. The result of this work is a method that allows equivalent or superior precision in comparison to the existing methods, whose main aspect is to eliminate the requirement of people entering dangerous environments, such as tumbling mills.


Author(s):  
Matt Narrol ◽  
Warren Stiver

Global climate change is one of the most important challenges and threats to economic, social and environmental sustainability.. Reducing electrical power demand is an important and necessary step in lessening global climate change and preserving our energy resources for future generations. The objective of this work is the development and demonstration of a quantitative thermographic system to rapidly and noninvasively determine in-use electrical motor efficiency. The development has included testing of four motors in a controlled laboratory setting. This setting permits the complete and steady measurement of electrical power draw, mechanical load applied in addition to the thermal imaging. It provides a reliable means to validate the quantitative thermographic system. The thermographic technique proved to be reliable for all motors at 60% or more of full load.


2021 ◽  
Vol 16 (6) ◽  
pp. 066019
Author(s):  
Shane Kyi Hla Win ◽  
Luke Soe Thura Win ◽  
Danial Sufiyan ◽  
Shaohui Foong

Abstract The monocopter is a type of micro aerial vehicle largely inspired from the flight of botanical samaras (Acer palmatum). A large section of its fuselage forms the single wing where all its useful aerodynamic forces are generated, making it achieve a highly efficient mode of flight. However, compared to a multi-rotor of similar weight, monocopters can be large and cumbersome for transport, mainly due to their large and rigid wing structure. In this work, a monocopter with a foldable, semi-rigid wing is proposed and its resulting flight performance is studied. The wing is non-rigid when not in flight and relies on centrifugal forces to become straightened during flight. The wing construction uses a special technique for its lightweight and semi-rigid design, and together with a purpose-designed autopilot board, the entire craft can be folded into a compact pocketable form factor, decreasing its footprint by 69%. Furthermore, the proposed craft accomplishes a controllable flight in 5 degrees of freedom by using only one thrust unit. It achieves altitude control by regulating the force generated from the thrust unit throughout multiple rotations. Lateral control is achieved by pulsing the thrust unit at specific instances during each cycle of rotation. A closed-loop feedback control is achieved using a motion-captured camera system, where a hybrid proportional stabilizer controller and proportional-integral position controller are applied. Waypoint tracking, trajectory tracking and flight time tests were performed and analyzed. Overall, the vehicle weighs 69 g, achieves a maximum lateral speed of about 2.37 m s−1, an average power draw of 9.78 W and a flight time of 16 min with its semi-rigid wing.


Author(s):  
Sreenath Gupta

Abstract Due to several recent developments in lasers and optics, laser igniters can now be designed to be (i) compact so as to have the same footprint as a standard spark plug, (ii) have low power draw, usually less than 50 Watts, and (iii) have vibration and temperature resistance at levels typical of reciprocating engines. Primary advantages of these laser igniters remain (i) extension of lean or dilution limits for ignition of combustible mixtures, and (ii) improved ignition at higher pressures. Recently, tests performed in a 350 kW 6-cylinder stationary natural gas reciprocating engine retrofitted with these igniters showed an extension of the operational envelope to yield efficiency improvements of the order of 2.6% points while being compliant with the mandated emission regulations. Even though laser igniters offer promise, fouling of the final optical element that introduces the laser into the combustion chamber is of concern. After performing a thorough literature search, a test plan was devised to evaluate various fouling mitigation strategies. The final approach that was used is a combination of three strategies and helped sustain an optical transmissivity exceeding 98% even after 1500 hrs. of continuous engine operation at 2400 rpm. Based on the observed trend in transmissivity, it now appears that laser igniters can last up to 6000 hrs. of continuous engine operation in a stationary engine running at 1800 rpm.


Author(s):  
Ryan Lewis ◽  
Hayley Schneider ◽  
Yunda Wang ◽  
Ray Radebaugh ◽  
Y. C. Lee

Micro cryogenic coolers (MCCs) operating in the Joule-Thomson cycle with mixed refrigerants offer an attractive way to decrease the size, cost, and power draw required for cryogenic cooling. Recent studies of MCCs with mixed refrigerants have, when employing pre-cooling, shown pulsating flow-rates and oscillating temperatures, which have been linked to the refrigerant flow regime in the MCC. In this study we investigate those flow regimes. Using a high-speed camera and optical microscopy, it is found that the pulsations in flow correspond to an abrupt switch from single-phase vapor flow to single-phase liquid flow, followed by 2-phase flow in the form of bubbles, liquid slugs, and liquid slug-annular rings. After this period of 2-phase flow, the refrigerant transitions back to single-phase vapor flow for the cycle to repeat. Under different pre-cooling temperatures, the mole fraction of the vapor-phase refrigerant, as measured by molar flow-rate, agrees reasonably well with the quality of the refrigerant at that temperature as calculated by an equation of state. The frequency of pulsation increases with liquid fraction in the refrigerant, and the volume of liquid in each pulse only weakly increases with increasing liquid fraction. The cooling power of the liquid-flow is up to a factor of 7 greater than that of the 2-phase flows and single-phase vapor flow.


2019 ◽  
Vol 144 ◽  
pp. 310-317 ◽  
Author(s):  
Wei-Ning Wu ◽  
Xiao-Yan Liu ◽  
Rong Zhang ◽  
Zhou Hu
Keyword(s):  

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