Band-Edge Photoresponse Characteristics of Diamond Msm's

1993 ◽  
Vol 302 ◽  
Author(s):  
Mike Marchywka ◽  
Steven C. Binari ◽  
Deborah A. Koolbeck ◽  
Daniel Moses
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Dark Current ◽  
Vacuum Ultraviolet ◽  
Light Signal ◽  
Band Edge ◽  
Metal Semiconductor Metal ◽  
Response Versus ◽  
Substrate Properties

ABSTRACTBand-edge photoresponse measurements on simple diamond metal-semiconductor-metal (MSM) devices can give information about the quality of the diamond material and its utility as a detector. We have fabricated several such devices on a variety of substrates and measured their response between 700 and 120nm with special emphasis around the band edge near 220nm. Steady state and transient response have been measured as a function of bias conditions. Transient response in this case refers to initial overshoot, undershoot, and increased dark current in response to a chopped vacuum ultraviolet (VUV) light signal for times on the order of seconds. We compare steady state quantum efficiency results to a simple model, discuss the characteristics of response versus applied voltage, and examine relationships between response and substrate properties.

scholarly journals Simulation based study on improving the transient response quality of turbocharged diesel engines

2017 ◽  
Vol 23 (3) ◽  
pp. 297-309 ◽  
Author(s):  
Rakesh Mishra ◽  
Syed Mohammad Saad
Keyword(s):  
Steady State ◽  
Diesel Engine ◽  
Quality Indicators ◽  
Transient Response ◽  
Operating Conditions ◽  
Compressor Wheel ◽  
Turbocharged Diesel Engine ◽  
Content Type ◽  
Wide Range

Purpose Use of fossil fuels in automotive sector is one of the primary causes of greenhouse emissions. The automotive engines need to perform at their best efficiency point to limit these emissions. Most of the quality indicators in this regard are based on near steady state global operational characteristics for engines without considering local performance. In the present study, extensive numerical simulations have been carried out covering a wide range of steady state and transient operating conditions to quantify interaction of turbocharger with engines through turbo lag phenomena which may cause increased emissions during the load change conditions. Furthermore possible innovations have been explored to minimize turbo lag phenomena. The paper aims to discuss these issues. Design/methodology/approach In this paper quality indicators have been developed to quantify the performance of turbocharged diesel engine under the transient event of rapid change in fueling rate which has been rarely investigated. The rate of fueling is changed from 40 mm3/injection to 52 mm3/injection at 1,000 rpm engine speed which corresponds to normal operating condition. To improve quality of transient response, torque assistance method and reduction of inertia of compressor wheel have been used. Parametric study has been undertaken to analyze the quality indicators such as outlet pressure of the compressor and the compressor speed. The turbo lag is quantified to obtain the close to optimal transient response of turbocharged diesel engine. Findings It has been shown that, with torque assist the transient response of the internal combustion engine is significantly improved. On the other hand, marginal improvement in transient response is observed by the reduction in inertia of the compressor wheel. Research limitations/implications The findings indicate that turbo lag can be minimized by providing torque assistance by active and passive means. Practical implications The developed methods can be used in practice for efficient operation of vehicles. Social implications The work carried out in the paper provides a way to minimize harmful emissions. Originality/value The quality indicators developed provide a quantitative measure of turbo lag phenomena and address the above mentioned problems.

scholarly journals A Head Formulation for the Steady-State Analysis of Water Distribution Systems Using an Explicit and Exact Expression of the Colebrook–White Equation

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1163
Author(s):  
Mengning Qiu ◽  
Avi Ostfeld
Keyword(s):  
Steady State ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Solution Method ◽  
Water Distribution System ◽  
Academic Research ◽  
Exact Expression ◽  
Contamination Source

Steady-state demand-driven water distribution system (WDS) solution is the bedrock for much research conducted in the field related to WDSs. WDSs are modeled using the Darcy–Weisbach equation with the Swamee–Jain equation. However, the Swamee–Jain equation approximates the Colebrook–White equation, errors of which are within 1% for ϵ/D∈[10−6,10−2] and Re∈[5000,108]. A formulation is presented for the solution of WDSs using the Colebrook–White equation. The correctness and efficacy of the head formulation have been demonstrated by applying it to six WDSs with the number of pipes ranges from 454 to 157,044 and the number of nodes ranges from 443 to 150,630. The addition of a physically and fundamentally more accurate WDS solution method can improve the quality of the results achieved in both academic research and industrial application, such as contamination source identification, water hammer analysis, WDS network calibration, sensor placement, and least-cost design and operation of WDSs.

Improved Load Sharing Control Techniques for Inverters used in a Microgrid

2009 ◽  
Vol 10 (1) ◽  
Author(s):  
Wei Yao ◽  
Zhaoming Qian
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Single Phase ◽  
Load Sharing ◽  
Power Sharing ◽  
Experimental Results ◽  
Control Technique ◽  
Transient Performance ◽  
Control Techniques ◽  
Control Scheme

In this paper, an improved load sharing control scheme is presented, which is able to improve the transient response and power sharing accuracy of parallel-connected inverters used in microgrid. It also shows how the improved droop method can be easily adapted to account for the operation of parallel-connected inverters, providing good performance under the variation and disturbance of loads, as well as achieving good steady-state objectives and transient performance. Two DSP-based single-phase Microgrid inverters are designed and implemented. Simulation and experimental results are all reported, confirming the validity of the proposed control technique.

scholarly journals Difficulty in Assessing Quality of Life Outcomes in a Fluctuating Disease: A Hypothesis Based on Gastroparesis

2009 ◽  
Vol 2009 ◽  
pp. 1-3 ◽  
Author(s):  
Vic Velanovich
Keyword(s):  
Quality Of Life ◽  
Steady State ◽  
Disease Process ◽  
Preliminary Finding ◽  
Median Number ◽  
Underlying Assumption ◽  
Clinical Encounters ◽  
Idiopathic Gastroparesis ◽  
Clinic Visits

An underlying assumption of quality of life outcome research is that after some intervention a “steady-state” of quality of life is reached which can be identified as an endpoint, and, hence, the “outcome.” However, in some disease processes, no so such steady-state is reached. The hypothesis presented is that a disease process with a waxing and waning course will make it difficult to determine a quality of life endpoint. After clinical observation, a pilot study of patients with either diabetic or idiopathic gastroparesis with gastric neurostimulation their records were reviewed to identify the number of clinic visits, the number of clinic visits in which the patients were asymptomatic, much improved, improved, no change, worse, or much worse. These changes were defined as “transitions.” A “transition ratio” was calculated by dividing the number of transitions by the number of clinic visits. Preliminary results showed that of 32 patients, the median number of clinic encounters was 8 (1–35), and the median number of transitions 4 (0–22). The average transition ration was . In the case of gastroparesis, over half of all clinical encounters were associated with a transition. The implication of the hypothesis and preliminary finding suggests a difficulty to identify when the symptomatic endpoint was reached. Other methods to assess the effects of treatment in such a disease process are required to fully understand the effects of treatment on quality of life.

Tuning pi untuk stabilitas kecepatan putaran motor induksi 1 fasa pada mesin penyaring bubur kedelai

JURNAL ELTEK ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 48
Author(s):  
Achmad Afandi ◽  
Mila Fauziyah Fauziyah ◽  
Denda Dewatama
Keyword(s):  
Steady State ◽  
Conventional Method ◽  
Rise Time ◽  
Settling Time ◽  
Screening Process ◽  
Pi Method ◽  
Filter Tube ◽  
Manual Methods ◽  
No Innovation

Perusahaan tahu di Indonesia pada umumnya, masih menggunakan cara manual, dalam pembuatannya khususnya pada proses penyaringan bubur kedelai yang membutuhkan waktu yang, lama. Hal tersebut didasarkan pada belum ditemukannya mesin pemeras bubur kedelai. Dewasa ini telah ditemukan inovasi mesin, pemeras bubur kedelai yang bisa meningkatkan kuantitas dan, kualitas produksi dibanding dengan cara manual. Penerapan, teknologinya adalah bubur kedelai diletakkan pada tabung, penyaring kemudian tabung tersebut diputar menggunakan motor, yang dihubungkan melalui fanbelt dan pulley. Ketika motor, diputar, tabung akan ikut berputar sehingga menimbulkan gerak, sentrifugal dimana air kedelai akan terpisah dari ampas. Kecepatan putar motor yang dikontrol adalah 750 rpm dengan, nilai Kp 0,108 , Ki 0,83 sehingga mendapatkan air sari kedelai, sebesar 1,3 liter dengan perbandingan 1 kg kedelai : 1 liter air. Parameter dari penerapan metode PI ini meliputi rise time 4 detik, settling time 4,5 detik, overshoot 0 dan error steady state 2,4%. Dengan penerapan metode PI maka hasil perasan kedelai dari, peyaringan menjadi semakin banyak dan waktu yang dibutuhkan 4 menit lebih singkat dibandingkan dengan cara konvensional.   Tofu companies in Indonesia generally still use manual methods in their manufacture, especially in the soybean slurry screening process which certainly has many disadvantages such as extortion time needed. This was based on the fact that there was no innovation in the soybean pulp squeezer. Currently, it has been found that innovations of soybean slurry machines can increase the quantity and quality of production compared to manual methods. The application of the technology is soybean slurry placed on the filter tube then the tube is rotated using a motor connected with fanbelt and pulley. When the motor is rotated, the tube will rotate, causing centrifugal motion where the soybean water will separate from the pulp. The speed of the motor controlled in 750 rpm with the Kp 0,108, Ki 0,83, to get soybean essence up to 1,3 liter within comparison 1 kg soybean : 1 liter water. The parameter PI method including rise time 4 second, settling time 4,5 second, overshoot 0 and error steady state 2,4%. By applying PI method, the result of filtering is 4 minute faster comparing with conventional method.

Steady-State and Transient Response of Selected All-Terrain Vehicles (ATVs)

1994 ◽  
Author(s):  
Graeme F. Fowler ◽  
Robert H. Fries ◽  
Roger L. McCarthy ◽  
Farshid A. Forouhar ◽  
Robert E. Larson
Keyword(s):  
Steady State ◽  
Transient Response

scholarly journals Suppression of dark current in GeO_x-passivated germanium metal-semiconductor-metal photodetector by plasma post-oxidation

2015 ◽  
Vol 23 (13) ◽  
pp. 16967 ◽  
Author(s):  
Jian Kang ◽  
Rui Zhang ◽  
Mitsuru Takenaka ◽  
Shinichi Takagi
Keyword(s):  
Dark Current ◽  
Metal Semiconductor Metal

Application of a Fuzzy Logic Controller for Speed Control on a Small-Scale Turbojet Engine

2014 ◽  
Author(s):  
Serdar Üşenmez ◽  
Sinan Ekinci ◽  
Oğuz Uzol ◽  
İlkay Yavrucuk
Keyword(s):  
Fuzzy Logic ◽  
Steady State ◽  
Transient Response ◽  
Fuzzy Logic Controller ◽  
Electronic Control Unit ◽  
Small Scale ◽  
Gas Temperature ◽  
Fuel Pump ◽  
Fuel Flow ◽  
Turbojet Engine

Having a small-scale turbojet engine operate at a desired speed with minimum steady state error, while maintaining good transient response is crucial in many applications, such as UAVs, and requires precise control of the fuel flow. In this paper, first the mathematical model of a Small-Scale Turbojet Engine (SSTE) is obtained using system identification tests, and then based on this model, a classical PI controller is designed. Afterwards, to improve on the transient response and steady state performance of this classical controller, a Fuzzy Logic Controller (FLC) is designed. The design process for the FLC employs logical deduction based on knowledge of the engine behavior and iterative tuning in the light of software- and hardware-in-the-loop simulations. The classical and fuzzy logic controllers are both implemented on an in-house, embedded Electronic Control Unit (ECU) running in real time. This ECU is an integrated device carrying a microcontroller based board, a fuel pump, fuel line valves, speed sensor and exhaust gas temperature sensor inputs, and starter motor and glow plug driver outputs. It mainly functions by receiving a speed reference value via its serial communication interface. Based on this reference, a voltage is calculated and applied to the fuel pump in order to regulate the fuel flow into the engine, thereby bringing the engine speed to the desired value. Pre-defined procedures for starting and stopping the engine are also automatically performed by the ECU. Further, it connects to a computer running an in-house comprehensive Graphical User Interface (GUI) software for operating, monitoring, configuration and diagnostics purposes. The designed controllers are used to drive a generic SSTE. Reference inputs consisting of step, ramp and chirp profiles are applied to the controllers. The engine response using both controllers are recorded and inspected. The results show that the FLC exhibits a comparable performance to the classical controller, with possible opportunities to improve this performance.

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