An application of theory to axial compressor noise

Mathematical model of aircraft turbocompressor nois

Topic doubling

Just like the vast majority of the Germanic languages, the Scandinavian languages are verb second (V2) languages where the finite verb occupies the second position in declarative clauses allowing just one constituent to precede it

Investigation of critical slowing down in a bistable S-SEED

A simulation of S-SEED switching based upon experimental data is developed that includes the effect of critical slowing down. The simulation's accuracy is demonstrated by close agreement with the results from experimental S-SEED switching. The simulation is subsequently used to understand how the phenomenon of critical slowing down applies to switching of an S-SEED and how the effect on photonic analog-to-digital (A/D) converter performance may be minimized.B. A. Clare, K. A. Corbett, K. J. Grant, P. B. Atanackovic, W. Marwood and J. Munc

Does Reproductive Investment Decrease Telomere Length in Menidia menidia?

Given finite resources, intense investment in one life history trait is expected to reduce investment in others. Although telomere length appears to be strongly tied to age in many taxa, telomere maintenance requires energy. We therefore hypothesize that telomere maintenance may trade off against other life history characters. We used natural variation in laboratory populations of Atlantic silversides (Menidia menidia) to study the relationship between growth, fecundity, life expectancy, and relative telomere length. In keeping with several other studies on fishes, we found no clear dependence of telomere length on age. However, we did find that more fecund fish tended to have both reduced life expectancy and shorter telomeres. This result is consistent with the hypothesis that there is a trade-off between telomere maintenance and reproductive output

An application of theory to axial compressor noise. Appendix C - Bessel functions of the first kind - A table of values for orders to 179 and arguments to 211

Application of theory to axial compressor nois

Experimental study of an organic Rankine cycle with R1233zd(E) for waste heat recovery from the coolant of a heavy-duty truck engine

Waste heat recovery is an effective method for improving engine efficiency. While most research on waste heat recovery from heavy-duty engines focuses on the high-temperature heat sources, this paper investigates the performance of a low-temperature system. The experimental setup features an organic Rankine cycle with R1233zd(E) as the working fluid recovering heat from the coolant of a heavy-duty Diesel engine. Experiments at multiple engine operating points indicated a maximum operating cycle pressure of 8 bar and temperature of 92 \ub0C. Between 0.1 and 0.7 kW net shaft power was achieved with a thermodynamic efficiency between 1.1 and 1.8%, resulting in a maximum expander power of 0.7% relative to the engine power. A simple empirical model based on the experimental results indicated that approximately 0.7% of the engine\u27s energy could be recovered during a driving cycle, rising to 1.3% if a high efficiency pump and expander are used. The main contribution of this paper lies in the presentation of the experimental setup and experimental results specifically dedicated to recovering the heat from the engine coolant, which permits realistic evaluation of the performance

Exhaust waste heat recovery from a heavy-duty truck engine: Experiments and simulations

Waste heat recovery using an (organic) Rankine cycle is an important and promising technology for improving engine efficiency and thereby reducing the CO2 emissions due to heavy-duty transport. Experiments were performed using a Rankine cycle with water for waste heat recovery from the exhaust gases of a heavy-duty Diesel engine. The experimental results were used to calibrate and validate steady-state models of the main components in the cycle: the pump, pump bypass valve, evaporator, expander, and condenser. Simulations were performed to evaluate the cycle performance over a wide range of engine operating conditions using three working fluids: water, cyclopentane, and ethanol. Additionally, cycle simulations were performed for these working fluids over a typical long haul truck driving cycle. The predicted net power output with water as the working fluid varied between 0.5 and 5.7 kW, where the optimal expander speed was dependent on the engine operating point. The net power output for simulations with cyclopentane was between 1.8 and 9.6 kW and that for ethanol was between 1.0 and 7.8 kW. Over the driving cycle, the total recovered energy was 11.2, 8.2, and 5.2 MJ for cyclopentane, ethanol, and water, respectively. These values correspond to energy recoveries of 3.4, 2.5, and 1.6%, respectively, relative to the total energy requirement of the engine. The main contribution of this paper is the presentation of experimental data on a complete Rankine cycle-based WHR system coupled to a heavy-duty engine. These results were used to validate component models for simulations, allowing for a realistic estimation of the steady-state performance under a wide range of operating conditions for this type of system

Experimental Results of a Waste Heat Recovery System with Ethanol Using Exhaust Gases of a Light-duty Engine

Organic Rankine cycle (ORC) waste heat recovery (WHR) systems have the potential to improve the efficiency of modern light-duty engines, especially at high-way driving conditions. This paper presents and discusses the experimental results of an engine connected to a compact ORC-WHR system with ethanol, suitable for integration in a modern passenger car. The aim is to show the added value of this ORC-WHR system for passenger cars by presenting the experimental results with the focus on the expander power output. The experimental setup consists of a Volvo Cars VEP-4 gasoline engine, which has an evaporator integrated in the exhaust pipe. During operation, one of two different states can be selected: electrical feedback (EFB) or mechanical feedback (MFB), where the expander can be either coupled to a 48V generator (EFB) or directly to the engine (MFB). Control strategies were developed to allow for operation of the system without interference of the driver. The results show that the current setup and control strategies can be successfully employed with significant expander power outputs for both MFB and EFB. The expander power outputs, similar for both states, go up to 2.5 kW, recovering 6.5% of the available exhaust energy and giving more than 5% improvement in fuel consumption

Feedback control of thermal lensing in a high optical power cavity

This paper reports automatic compensation of strong thermal lensing in a suspended 80 m optical cavity with sapphire test mass mirrors. Variation of the transmitted beam spot size is used to obtain an error signal to control the heating power applied to the cylindrical surface of an intracavity compensation plate. The negative thermal lens created in the compensation plate compensates the positive thermal lens in the sapphire test mass, which was caused by the absorption of the high intracavity optical power. The results show that feedback control is feasible to compensate the strong thermal lensing expected to occur in advanced laser interferometric gravitational wave detectors. Compensation allows the cavity resonance to be maintained at the fundamental mode, but the long thermal time constant for thermal lensing control in fused silica could cause difficulties with the control of parametric instabilities.This research was supported by the Australian Research Council and the Department of Education, Science and Training and by the U.S. National Science Foundation, through LIGO participation in the HOPF