Improved QSS-μPCD measurement with quality of decay control: Correlation with steady-state carrier lifetime

2012 ◽  
Vol 106 ◽  
pp. 66-70 ◽  
Author(s):  
Marshall Wilson ◽  
Piotr Edelman ◽  
Jacek Lagowski ◽  
Sara Olibet ◽  
Valentin Mihailetchi
Keyword(s):  
Steady State ◽  
Carrier Lifetime

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.

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.

scholarly journals Improving the quality of alumina-containing sinter using water-cooled furnace shell

2012 ◽  
Vol 44 (3) ◽  
pp. 281-286
Author(s):  
A.V. Aleksandrov ◽  
V.V. Aleksandrov
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Exchange ◽  
Energy Balance ◽  
Cold Water ◽  
Sintering Temperature ◽  
Radiant Heat ◽  
Thermal Processes ◽  
Technical Solutions

This article deals with the use of computer modeling to develop technical solutions to ensure better quality of alumina-containing sinter. The simulation accounted for the influence of the feed materials on the thermal processes in the furnace. The energy balance (including thermal conductivity, heat convection and radiant heat exchange) was solved assuming steady state. A good correlation was observed for the actual and calculated temperatures of the solids and gases, with less than 15% discrepancy. Using the model of the furnace investigated the possibility of lowering the temperature of sintering by removing heat from the outside of the furnace shell. To reduce the sintering temperature to 1000 ?C length of the refractory lined steel is 5 m, the height of the lining should not exceed - 0.06 m, the required rate of cold water - 54.7 m3/h

FEM Simulation of Copper Busbar Pressing on the Continuous Extrusion Line "CONFORM"

2018 ◽  
Vol 284 ◽  
pp. 547-551
Author(s):  
Georgy V. Shimov ◽  
Aleksandr Bogatov ◽  
D. Kovin
Keyword(s):  
Steady State ◽  
Deformation Zone ◽  
Metal Flow ◽  
Fem Simulation ◽  
Continuous Extrusion ◽  
3D Package ◽  
Deform 3D

Simulation using the DEFORM-3D package of the steady-state pressing mode of a copper busbar on the continuous extrusion line "Conform" was carried out. The nature of the metal flow in the deformation zone was studied. An analysis of the velocities of the metal flow in the prechamber was performed. It was shown that in the channel of the wheel there is pressing out, which negatively affects the quality of the finished busbars and can lead to such defects as "lamination".

Homoepitaxial Chemical Vapor Deposition of up to 150 μm Thick 4H-SiC Epilayers in a 10×100 mm Batch Reactor

2016 ◽  
Vol 858 ◽  
pp. 129-132 ◽  
Author(s):  
Bernd Thomas ◽  
Jie Zhang ◽  
Gil Yong Chung ◽  
Willie Bowen ◽  
Victor Torres ◽  
...  
Keyword(s):  
Carrier Lifetime ◽  
Statistical Data ◽  
Laser Light ◽  
Defect Density ◽  
Batch Reactor ◽  
Chemical Vapor ◽  
Layer Growth ◽  
Average Lifetime ◽  
Thick Layers

In this paper we present results on the growth of low-doped thick epitaxial layers on 4° off-oriented 4H-SiC using a warm-wall multi-wafer CVD system (Aixtron VP2800WW). Statistical data on doping and thickness of 25 μm to 40 μm layer growth show results similar to standard epilayer growth (5-15 μm). Improvements in thickness and doping uniformity as well as the reduction of epitaxial defects has boosted the quality of 25 μm to 40 μm thick epilayers. Laser light scattering measurements resulted in projected device yields with median values of 83% and 96% for 5×5 mm2 and 2×2 mm2 die size, respectively. This corresponds to a low epitaxial defect density of < 0.75 cm-2 in 25-40 μm thick epilayers. This paper also presents results of 60 μm to 150 μm thick epitaxial layer growth. Excellent results for doping, thickness and carrier lifetime were achieved. As an example results of a fully loaded 10×100mm run with 150 μm thick epilayers are presented. Wafer-to-wafer doping and thickness values of 3.7 % and 3.4% for sigma/mean were accomplished, respectively. Typical average lifetime values of 5 μs to 6 μs were measured on the 150 μm thick layers without post-epi treatments.

Minority carrier lifetime in silicon wafers from quasi-steady-state photoluminescence

2010 ◽  
Vol 97 (9) ◽  
pp. 092109 ◽  
Author(s):  
J. A. Giesecke ◽  
M. C. Schubert ◽  
D. Walter ◽  
W. Warta
Keyword(s):  
Steady State ◽  
Carrier Lifetime ◽  
Minority Carrier ◽  
Minority Carrier Lifetime ◽  
Silicon Wafers ◽  
Quasi Steady State

scholarly journals Characteristics of modeling hydrodynamic processes of fuel supply in operation of marine diesel using water-fuel emulsion

2020 ◽  
Vol 2020 (2) ◽  
pp. 54-61
Author(s):  
Gennady Bentsianovich Gorelik ◽  
Oleg Nikolaevich Mozolev
Keyword(s):  
High Pressure ◽  
Steady State ◽  
Diesel Fuel ◽  
Alternative Fuels ◽  
Alternative Fuel ◽  
Telegraph Equation ◽  
Maximum Pressure ◽  
Fuel Supply ◽  
Marine Diesel

The article presents the results of mathematical modeling of the fuel supply process of a marine diesel working on diesel fuel and water-fuel emulsion with a water content of 30% as an alternative fuel. There have been found the specific features of fuel supply and the influence of the alternative fuel on the injection characteristics of standard fuel supply equipment during operation in nominal and partial modes. In evaluating the quality of fuel equipment operation on a water-fuel emulsion there were taken into account the following facts: changing of the fuel supply characteristics; changing injection parameters; type of fuel spraying in the initial and final phases of injection and reduction of fuel proportion supplied during the needle landing period; greater stability of successive injection cycles by increasing the active stroke of the plunger by 25-30%; features of injection processes due to thermal explosion effect. The telegraph equation for the unsteady fuel motion in a high pressure pipeline is obtained. The operation parameters of a marine diesel engine 6CHSPN2A 18/22 (DRA-300) are considered in nominal mode according to the screw characteristic for diesel fuel and water-fuel emulsion: plunger stroke of the high-pressure fuel pump; maximum pressure of the steady state in the connecting pipe; average integral pressure of the steady state in the nozzle, which determines the quality of spraying, the speed of landing of the sprayer needle on the saddle; amount of fuel supplied during the needle landing period; cyclic fuel supply; duration of the main injection; stability criterion of fuel supply processes in successive cycles, etc. It has been inferred that water-fuel emulsions can take a separate place in the list of alternative fuels, which will contribute to improving the quality of traditional fuels, productive burnout of hydrocarbon, nitrogen-hydrogen mixture, spirit mixtures, etc. due to the rational introducing additives into fuel, increasing the reliability indicators of cylinder-piston parts, etc.

Sign in / Sign up

Export Citation Format

Share Document