scholarly journals A Fibre Optic Probe for Gas Total Temperature Measurement in Turbomachinery

1994 ◽  
Author(s):  
S. R. Kidd ◽  
J. S. Barton ◽  
P. Meredith ◽  
J. D. C. Jones ◽  
M. A. Cherrett ◽  
...  
Keyword(s):  
High Speed ◽  
Gas Temperature ◽  
Sensing Element ◽  
Fibre Optics ◽  
Unsteady Temperature ◽  
Multi Stage ◽  
Fibre Optic Probe ◽  
High Bandwidth ◽  
New Type ◽  
Optic Probe

This paper describes the design, operation, construction and demonstration of a new type of high bandwidth unsteady temperature sensor based on fibre optics, and capable of operating in a high speed multi-stage research compressor with flow representative of jet engine conditions. The sensing element is an optical coating of zinc selenide deposited on the end of an optical fibre. During evaluation in aerodynamic testing, a 1 K gas temperature resolution was demonstrated at 9.6 kHz and an upper bandwidth limit of 36 kHz achieved.

A Fiber Optic Probe for Gas Total Temperature Measurement in Turbomachinery

1995 ◽  
Vol 117 (4) ◽  
pp. 635-641 ◽  
Author(s):  
S. R. Kidd ◽  
J. S. Barton ◽  
P. Meredith ◽  
J. D. C. Jones ◽  
M. A. Cherrett ◽  
...  
Keyword(s):  
Fiber Optics ◽  
High Speed ◽  
Gas Temperature ◽  
Fiber Optic Probe ◽  
Sensing Element ◽  
Unsteady Temperature ◽  
High Bandwidth ◽  
New Type ◽  
Total Temperature ◽  
Optic Probe

This paper describes the design, operation, construction, and demonstration of a new type of high-bandwidth unsteady temperature sensor based on fiber optics, and capable of operating in a high-speed multistage research compressor with flow representative of jet engine conditions. The sensing element is an optical coating of zinc selenide deposited on the end of an optical fiber. During evaluation in aerodynamic testing, a 1 K gas temperature resolution was demonstrated at 9.6 kHz and an upper bandwidth limit of 36 kHz achieved.

Light Railways as the Basic for Transport Infrastructure Development in Northern Territories of Russia

2020 ◽  
pp. 97-101
Author(s):  
P.I. Tarasov
Keyword(s):  
High Speed ◽  
Road Transport ◽  
Transport Infrastructure ◽  
The Arctic ◽  
Infrastructure Development ◽  
Capital Costs ◽  
New Type ◽  
The Republic ◽  
Northern Territories ◽  
Mode Of Transport

Research objective: studies of economic and transport infrastructure development in the Arctic and Northern Territories of Russia. Research methodology: analysis of transport infrastructure in the Republic of Sakha (Yakutia) and the types of railways used in Russia. Results: economic development of any region is proportional to the development of the road transport infrastructure and logistics. When a conventional railway is operated in the Arctic conditions, it is not always possible to maintain a cargo turnover that would ensure its efficient use, and transshipment from one mode of transport to another is very problematic. A new type of railway is proposed, i.e. a light railway. Conclusions: the proposed new type of transport offers all the main advantages of narrow gauge railroads (high speed of construction, efficiency, etc.) and helps to eliminate their main disadvantage, i.e. the need for transloading when moving from a narrow gauge to the conventional one with the width of 1520 mm, along with a significant reduction in capital costs.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

scholarly journals NanoLEDs for energy-efficient and gigahertz-speed spike-based sub-λ neuromorphic nanophotonic computing

Nanophotonics ◽  
2020 ◽  
Vol 9 (13) ◽  
pp. 4149-4162 ◽  
Author(s):  
Bruno Romeira ◽  
José M. L. Figueiredo ◽  
Julien Javaloyes
Keyword(s):  
Neural Networks ◽  
Energy Efficient ◽  
High Speed ◽  
Dynamic Properties ◽  
Optical Computing ◽  
Differential Conductance ◽  
Rate Equations ◽  
Dynamical Equations ◽  
Electrical Modulation ◽  
High Bandwidth

AbstractEvent-activated biological-inspired subwavelength (sub-λ) photonic neural networks are of key importance for future energy-efficient and high-bandwidth artificial intelligence systems. However, a miniaturized light-emitting nanosource for spike-based operation of interest for neuromorphic optical computing is still lacking. In this work, we propose and theoretically analyze a novel nanoscale nanophotonic neuron circuit. It is formed by a quantum resonant tunneling (QRT) nanostructure monolithic integrated into a sub-λ metal-cavity nanolight-emitting diode (nanoLED). The resulting optical nanosource displays a negative differential conductance which controls the all-or-nothing optical spiking response of the nanoLED. Here we demonstrate efficient activation of the spiking response via high-speed nonlinear electrical modulation of the nanoLED. A model that combines the dynamical equations of the circuit which considers the nonlinear voltage-controlled current characteristic, and rate equations that takes into account the Purcell enhancement of the spontaneous emission, is used to provide a theoretical framework to investigate the optical spiking dynamic properties of the neuromorphic nanoLED. We show inhibitory- and excitatory-like optical spikes at multi-gigahertz speeds can be achieved upon receiving exceptionally low (sub-10 mV) synaptic-like electrical activation signals, lower than biological voltages of 100 mV, and with remarkably low energy consumption, in the range of 10–100 fJ per emitted spike. Importantly, the energy per spike is roughly constant and almost independent of the incoming modulating frequency signal, which is markedly different from conventional current modulation schemes. This method of spike generation in neuromorphic nanoLED devices paves the way for sub-λ incoherent neural elements for fast and efficient asynchronous neural computation in photonic spiking neural networks.

The Application of Mechanism Theory to a Textile Machinery Innovation

1976 ◽  
Vol 190 (1) ◽  
pp. 367-378 ◽  
Author(s):  
G. R. Wray
Keyword(s):  
High Speed ◽  
Practical Experience ◽  
Mechanism Analysis ◽  
The Novel ◽  
Traditional Practice ◽  
Textile Technology ◽  
Theoretical Investigations ◽  
Analysis And Synthesis ◽  
New Type ◽  
Machinery Manufacturing

The design of mechanisms for use in practical machinery applications is often of a trial-and-error nature based on traditional practice. Much emphasis has been given to the theory of mechanisms in recent years but this has yet to find wide practical application. This paper is a case study of how a basic idea, conceived by University-based inventors and intended to improve a slow method of making a textile pile fabric, became a reality in the form of a completely new type of high-speed textile machine for making an improved textile product, all within a time scale of four years. It also shows how recent University researches are further advancing its potential from both the machinery manufacturing and textile technology aspects. Step-by-step from the early experimental stages, it illustrates how the challenges of developing the novel mechanisms required for this unconventional machine and process were met by combining practical experience of traditional machinery design with theoretical investigations based on the new techniques of mechanism analysis and synthesis.

scholarly journals Numerical and Experimental Investigation on Key Parameters of the Respimat® Spray Inhaler

Processes ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Yi Ge ◽  
Zhenbo Tong ◽  
Renjie Li ◽  
Fen Huang ◽  
Jiaqi Yu
Keyword(s):  
High Speed ◽  
Fine Particles ◽  
Geometric Parameters ◽  
Metered Dose Inhalers ◽  
Geometric Pattern ◽  
Long Duration ◽  
Metered Dose ◽  
New Type ◽  
Computational Fluid Dynamics Cfd ◽  
Spray Velocity

Respimat®Soft MistTM is a newly developed spray inhaler. Different from traditional nebulizers, metered-dose inhalers, and dry powder inhalers, this new type of inhaler can produce aerosols with long duration, relatively slow speed, and a high content of fine particles. Investigating the effect of the key geometric parameters of the device on the atomization is of great significance for generic product development and inhaler optimization. In this paper, a laser high-speed camera experimental platform is built, and important parameters such as the geometric pattern and particle size distribution of the Respimat®Soft MistTM are measured. Computational fluid dynamics (CFD) and the volume of fluid method coupled with the Shear Stress Transport (SST) k-ω turbulence model are applied to simulate the key geometric parameters of the device. The effects of geometric parameters on the spray velocity distribution and geometric pattern are obtained. The angle of flow collision, the sphere size of the central divider and the length and width of the flow channel show significant impacts on the spray atomization.

A 25 Gbps VCSEL driving ASIC: an attempt for ultra-high-speed front-end readout applications

2022 ◽  
Vol 17 (01) ◽  
pp. C01040
Author(s):  
C. Zhao ◽  
D. Guo ◽  
Q. Chen ◽  
N. Fang ◽  
Y. Gan ◽  
...  
Keyword(s):  
High Speed ◽  
Cmos Technology ◽  
Test Results ◽  
Eye Diagram ◽  
Optical Links ◽  
Optical Module ◽  
Active Feedback ◽  
High Bandwidth ◽  
Output Driver ◽  
Very High

Abstract This paper presents the design and the test results of a 25 Gbps VCSEL driving ASIC fabricated in a 55 nm CMOS technology as an attempt for the future very high-speed optical links. The VCSEL driving ASIC is composed of an input equalizer stage, a pre-driver stage and a novel output driver stage. To achieve high bandwidth, the pre-driver stage combines the inductor-shared peaking structure and the active-feedback technique. A novel output driver stage uses the pseudo differential CML driver structure and the adjustable FFE pre-emphasis technique to improve the bandwidth. This VCSEL driver has been integrated in a customized optical module with a VCSEL array. Both the electrical function and optical performance have been fully evaluated. The output optical eye diagram has passed the eye mask test at the data rate of 25 Gbps. The peak-to-peak jitter of 25 Gbps optical eye is 19.5 ps and the RMS jitter is 2.9 ps.

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