scholarly journals РЕШЕНИЕ ЗАДАЧИ СТАБИЛИЗАЦИИ ТЕМПЕРАТУРЫ ВОЗДУХА В КАБИНЕ ТРАНСПОРТНОГО СРЕДСТВА

2018 ◽  
pp. 12-19
Author(s):  
Сергей Николаевич Пасичник ◽  
Дмитрий Вадимович Сокол
Keyword(s):  
Steady State ◽  
Thermal Load ◽  
Transfer Functions ◽  
Open Loop ◽  
Frequency Characteristics ◽  
Temperature Stabilization ◽  
Frequency Method ◽  
Vehicle Cabin ◽  
Static Calculation

The subject matter of the article is the processes of synthesis of the automatic stabilization system (ASS) of the temperature in the vehicle cabin simulator using the vortex energy separator (VES) as the executive element of the system. The goal is to correct element synthesis of the ASS (CEs), which provides stability and quality of stabilization with the intensive change in the thermal load. The tasks to be solved are: to construct the functional scheme of the ASS which consist of the positioning circuit of the modes of the VES and the air temperature stabilization circuit in the cabin simulator; applying the results of solving the problem of synthesis of the automatic positioning system (APS) of modes of the VES, construct the structural diagram and mathematical model of the ASS of the temperature in the form of interval transfer functions (TF); perform the static calculation of the system to ensure the accuracy in steady-state and transient modes with linearly varying input influences; solve the problem of ensuring stability and dynamic levels of quality of the temperature stabilization using interval logarithmic amplitude-frequency characteristics (LAFC) and indirect levels of quality of the system's functioning in the frequency domain. The applied methods are: LAFC, real frequency characteristics. The following results were obtained: the functional and structural schemes of the ASS of the temperature in the vehicle cabin simulator are constructed, the interval transfer functions of the open-loop and closed-loop system are determined according to the referencing and disturbing influences. The static calculation of the system is performed to determine the required value of the transfer coefficient of the open-loop ASS based on the condition of ensuring the accuracy of the system in the steady-state mode of operation and with the intensive change in the thermal load. The dynamic calculation of the system was performed, as a result of which the structure and parameters of the CEs were determined based on the analysis of the dependence of the phase stability margin and the cut-off frequency on the values of the parameters of the CEs in accordance with the requirements for dynamic levels of quality. Conclusions. The scientific novelty of the results obtained is following: the frequency method of synthesis of the ASS using interval LAFC has been further developed by investigating the behavior of the logarithmic characteristics on the boundaries of the intervals of parameters of the transfer function of close-loop APS of the of the VES

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 Converting MST to TSP Path by Branch Elimination

2020 ◽  
Vol 11 (1) ◽  
pp. 177
Author(s):  
Pasi Fränti ◽  
Teemu Nenonen ◽  
Mingchuan Yuan
Keyword(s):  
Spanning Tree ◽  
Closed Loop ◽  
Minimum Spanning Tree ◽  
Travelling Salesman Problem ◽  
Open Loop ◽  
Travelling Salesman ◽  
Elimination Algorithm ◽  
Number Of Iterations ◽  
Number Of Branches

Travelling salesman problem (TSP) has been widely studied for the classical closed loop variant but less attention has been paid to the open loop variant. Open loop solution has property of being also a spanning tree, although not necessarily the minimum spanning tree (MST). In this paper, we present a simple branch elimination algorithm that removes the branches from MST by cutting one link and then reconnecting the resulting subtrees via selected leaf nodes. The number of iterations equals to the number of branches (b) in the MST. Typically, b << n where n is the number of nodes. With O-Mopsi and Dots datasets, the algorithm reaches gap of 1.69% and 0.61 %, respectively. The algorithm is suitable especially for educational purposes by showing the connection between MST and TSP, but it can also serve as a quick approximation for more complex metaheuristics whose efficiency relies on quality of the initial solution.

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.

Responses and Optimization of a PID-Based Speed Regulating System of the Planetary Mixer

2011 ◽  
Vol 418-420 ◽  
pp. 1865-1868
Author(s):  
Ming Jin Yang ◽  
Xi Wen Li ◽  
Zhi Gang Wang ◽  
Tie Lin Shi
Keyword(s):  
Control System ◽  
Open Loop ◽  
Open Loop Control ◽  
Efficient Operation ◽  
Loop Control ◽  
Loop Control System ◽  
Response Optimization ◽  
Close Loop Control ◽  
Close Loop Control System

The performance of speed regulating is very important to the mixing process with safe, efficient operation and high quality of production. Strategies and practices of responses and optimization of a PID-based speed regulating system of a planetary mixer were presented in this paper. Research results show that: by means of the signal constraint function presented by Simulink Response Optimization, optimization PID parameters of the 2-DOF-PID controller can be obtained, and the response of close-loop control system has quite good performance of overshoot, response time, and stability compared with an open-loop control system.

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

scholarly journals Modeling the Peach Sugar Contents in Relation to Fruit Growth

1996 ◽  
Vol 121 (6) ◽  
pp. 1122-1131 ◽  
Author(s):  
Michel Génard ◽  
Michel Souty
Keyword(s):  
Growth Curve ◽  
Prunus Persica ◽  
Transfer Functions ◽  
Dry Weight ◽  
Fruit Growth ◽  
Data Sets ◽  
Weight Growth ◽  
Using Data ◽  
Good Agreement

The edible quality of peaches (Prunus persica L. Batsch) to a great extent depends on their sweetness, which is related to sugar composition. Our objective was to develop a model to predict carbon partitioning within fruit flesh and to predict the sucrose, sorbitol, glucose, and fructose contents. The model is dynamic and deterministic and was designed to be driven by the flesh dry-weight growth curve, flesh water content, and temperature data. It uses differential equations where the state of the system is defined by variables that describe how much carbon is present as each form of sugar and as other compounds (acids and structural carbohydrates). The rates of change of these amounts of carbon depend on the current values of corresponding variables and on the transfer functions between them. These functions are defined by rate constants or by functions of degree-days after full bloom. The model was calibrated and tested using data sets from treatments that covered several leaf: fruit ratios. The predictions of the model were in fairly good agreement with experimental data. A sensitivity analysis was performed to identify the most influential transfer function parameters. Carbon flows between sugar forms were analyzed. Sucrose, which was the most abundant sugar, and fructose, which is the sweetest, contributed most to fruit sweetness. Simulations were performed to study the effects of changes in fruit growth-curve parameters on sugar contents and concentrations.

scholarly journals PI- Controlled PV Fed Fly Back Converter with Enhanced Dynamic Response

2019 ◽  
Vol 8 (2S11) ◽  
pp. 4031-4034
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Rise Time ◽  
Closed Loop ◽  
Input Voltage ◽  
Pi Controller ◽  
Open Loop ◽  
Load Variations ◽  
Simulink Model ◽  
Step Down

Fly back converter is the most popular converter because of its simplicity, low part counts and isolation. It occupies less volume and it saves cost. Fly back converter steps up and step down the voltage with the same polarity. Open loop operation remains insensitive to the input voltage and load variations. Matlab Simulink model for Fly back converter is established using PI controller. Open loop Fly back converter system and closed loop fly back converter systems are simulated and their outcomes are compared. Comparison is done in terms of Rise time ,Settling time and steady state error

A scheme for expressing instrumental responses parametrically

1977 ◽  
Vol 67 (3) ◽  
pp. 957-969 ◽  
Author(s):  
Peter C. Luh
Keyword(s):  
Transfer Function ◽  
Linear Systems ◽  
Hilbert Transform ◽  
Transfer Functions ◽  
Poor Quality ◽  
Phase Response ◽  
Seismic Instrument ◽  
Amplitude Response ◽  
Response Range

abstract This study shows that, provided a seismic instrument as a whole behaves linearly over its response range, and provided its phase response is known accurately, the instrumental responses can be parametrically expressed in terms of transfer functions of linear systems. The scheme is based on the observation that knowing accurately the detailed overall amplitude and phase responses of a linear instrument is tantamount to knowing all the pertinent constants for the construction of its overall transfer function. Because of generally poor quality of empirical phase calibrations, empirical phases are substituted by minimum phases, calculated via a Hilbert transform of amplitude response. Application of the scheme to actual SRO (LP) and USGS (SP) instruments resulted in sufficiently close agreements between parametric and actual responses to warrant the utility of the scheme.

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