scholarly journals A Reliability Model for a Two Dissimilar Units Series System with Repair Time-Dependent Standby

2020 ◽  
Vol 9 (3) ◽  
pp. 2890-2893
Keyword(s):  
Aluminum Industry ◽  
Repair Time ◽  
Reliability Model ◽  
System Optimum ◽  
System A ◽  
Regenerative Point ◽  
In Series ◽  
Series Configuration ◽  
Configuration System ◽  
Regenerative Point Technique

The present paper stochastically analyze a system comprising two dissimilar units (unit-1/unit-2) working in series configuration. System fails completely when either of the units gets failed. The repair time of unit-2 is considered to be much more as compared to the repair time of unit-1. So, to minimize the breakdown period of the system, a standby unit is provided against the second unit. Regenerative point technique (RPT) is used to develop a semi-markovian reliability model for the mentioned system. Optimum cut-off points concerning the profitability of the system have also been obtained. The model has applications in industries, particularly in aluminum industry.

scholarly journals Determining the environmental indicators for vehicles of different categories in relation to CO2 emission based on road tests

2017 ◽  
Vol 170 (3) ◽  
pp. 66-72
Author(s):  
Jerzy MERKISZ ◽  
Łukasz RYMANIAK
Keyword(s):  
Co2 Emissions ◽  
Operating Time ◽  
Environmental Indicators ◽  
Operating Conditions ◽  
Si Engine ◽  
Propulsion Systems ◽  
System A ◽  
In Series ◽  
Series Configuration ◽  
Ci Engine

The article discusses the possibility of determining the environmental indicators for vehicles of different categories in relation to CO2 emissions. These are called toxicity indicators because they concern the compounds: CO, THC and NOx. Three Euro V compliant vehicles with different propulsion systems types were used for the study: a 0.9 dm3 urban passenger car with a SI engine and a start-stop system, a 2.5 dm3 off-road vehicle with a CI engine, and a city bus with a hybrid drive system in series configuration and a CI engine with a displacement of 6.7 dm3. Measurements were made in actual operating conditions in the Poznan agglomeration using a portable emissions measurement system (PEMS). The paper presents the characteristics of the operating time shares of vehicles and propulsion systems as well as CO2 emissions depending on the engine load and crankshaft rotational speed for individual vehicles. The determined toxicity indicators allowed to indicate their usefulness, to make comparisons between tested vehicles, and to identify directions for further work on the application and interpretation of these indicators.

Determination of Optimal Reserve between Two Machines in Series with the Repair Time has Change of Distribution after the Truncation Point

GIS Business ◽  
2019 ◽  
Vol 14 (6) ◽  
pp. 577-585
Author(s):  
T. Vivekanandan ◽  
S. Sachithanantham
Keyword(s):  
Real Life ◽  
Random Variable ◽  
Repair Time ◽  
Inventory Level ◽  
Optimal Size ◽  
Truncation Point ◽  
In Series ◽  
Optimal Reserve ◽  
Optimal Inventory Level ◽  
Two Machines

In inventory control, suitable models for various real life systems are constructed with the objective of determining the optimal inventory level.  A new type of inventory model using the so-called change of distribution property is analyzed in this paper. There are two machines M1 and M2  in series and the output of M1 is the input of M2. Hence a reserve inventory between M1 and M2 is to be maintained. The method of obtaining the optimal size of reserve inventory, assuming cost of excess inventory, cost of shortage and when the rate of consumption of M2  is a constant, has already been attempted.  In this paper, it is assumed that the repair time of M1  is a random variable and the distribution of the same undergoes a change of distribution  after the truncation point X0 , which is taken to be a random variable.  The optimal size of the reserve inventory is obtained under the above said  assumption . Numerical illustrations are also provided.

Poly Silk Peptide Film PH Sensor Based on Zero Current Potentiometry

2012 ◽  
Vol 450-451 ◽  
pp. 554-556
Author(s):  
Ming Ming Ma ◽  
Zhi Tong ◽  
Yong Wen
Keyword(s):  
Graphite Electrode ◽  
Ph Sensor ◽  
Reference Electrode ◽  
Pencil Graphite Electrode ◽  
Solution Ph ◽  
Counter Electrodes ◽  
System A ◽  
Zero Current ◽  
In Series ◽  
Silk Peptide

A poly silk peptide film pH sensor has been developed using zero current potentiometry system. A poly silk peptide film coated pencil graphite electrode is connected in series between the working and counter electrodes of a potentiostat, and immersed in solution together with a reference electrode. When the solution pH varies, the resulting zero current potentiometry is linear with the values of the solution pH in the range of 1.81 to 11.58. This pH sensor shows high stability, accuracy, selectivity and reproduction.

scholarly journals Preparative-Capillary Gas Chromatographic Systems for Trace Analysis of Rum

1969 ◽  
Vol 60 (4) ◽  
pp. 559-584
Author(s):  
Heriberto Batiz ◽  
Elena Soltero
Keyword(s):  
Stainless Steel ◽  
Puerto Rican ◽  
Alcoholic Beverages ◽  
Complete Analysis ◽  
Volatile Fraction ◽  
Rapid Preparation ◽  
Porapak Q ◽  
The Third ◽  
System A ◽  
In Series

Three gas chromatographic systems a ppropriate for the reproducible rapid preparation and subsequent quantitative analysis of rum concentrates were developed and tested. The first and second systems employed preparative columns directly coupled to a capillary Golay column. Rum concentrates obtained in the preparative column were collected in a stainless steel trap of low dead space and simultaneously analyzed in the capillary system by flash heating of the trap. The third system used the same chromatographic equipment, with a 1/4-in o.d. trap to transfer an amount of concentrate to a 2-ml vial. These concentrates were subsequently analyzed with two Golay columns. In the first system, a 10-ft 20% Carbowax 20M packed preparative column coupled to a 150-ft Golay column through a 1/8-in o.d. trap gave excellent results in the analysis of the volatile fraction of rums. Ten congeners eluting before alcohol were detected in a commercial rum, six of which have not been identified. The second system, utilizing the 10-ft Carbowax 20M coupled to a 7-ft Porapak Q preparative column, was tested successfully with a 1/8-in o.d. trap. About 30 congeners were detected in the same commercial Puerto Rican rum. A 7-ft Porapak Q packed preparative column was investigated in the third system provided with a 1/4-in o.d. trap. About 40 congeners were detected in two commercial Puerto Rican rums utilizing a 50-ft SE-30 Golay column in series with a 150-ft Carbowax 20M Golay column. Results demonstrate the feasibility of obtaining a rapid and complete analysis of distilled alcoholic beverages.

Prostaglandin modulation of adrenergic vascular control during hemorrhagic shock

1981 ◽  
Vol 241 (1) ◽  
pp. H85-H90 ◽  
Author(s):  
R. F. Bond ◽  
C. H. Bond ◽  
L. C. Peissner ◽  
E. S. Manning
Keyword(s):  
Skeletal Muscle ◽  
Hemorrhagic Shock ◽  
Vascular Control ◽  
Synthesis Inhibitor ◽  
Muscle Perfusion ◽  
System A ◽  
In Series ◽  
Adrenergic Nervous System ◽  
Prostaglandin Synthesis Inhibitor ◽  
Denervated Muscles

This study was designed to evaluate 1) whether the initial compensatory skeletal muscle vascular constriction induced by hemorrhagic hypotension is primarily the result of increased adrenergic neural tone rather than circulating vasoconstrictor agents, and 2) whether the secondary skeletal muscle decompensatory vasodilation is caused by inhibitory action of prostaglandins on peripheral adrenergic nervous system. A constant-flow vascularly isolated double canine gracilis muscle preparation in which one muscle served as innervated control for the contralateral muscle was used. Dogs were subjected to standard stepwise hemorrhagic shock protocol. In series 1, perfusion pressures of control muscles were compared to denervated muscles with the result that innervated muscle perfusion pressures increased initially from 105 to 175 mmHg but subsequently fell significantly (P less than 0.05) to 147 mmHg. Only modest increases in perfusion pressures with no significant secondary fall were noted in denervated muscles. Series 2 compared innervated control perfusion pressures to pressures perfusing muscles pretreated with prostaglandin-synthesis inhibitor sodium meclofenamate (MCF). The MCF-treated muscle perfusion pressures rose to 260 mmHg where they remained without the secondary fall noted in control muscles. These data support the two hypotheses tested.

MICROWAVE MEMS SWITCHES IN SERIES CONFIGURATION: TECHNOLOGY AND CIRCUITAL MODELING

2005 ◽  
Author(s):  
R. MARCELLI ◽  
F. GIACOMOZZI ◽  
B. MARGESIN ◽  
G. BARTOLUCCI ◽  
G. MINUCCI
Keyword(s):  
Mems Switches ◽  
In Series ◽  
Series Configuration

BTEX degradation in a cold-climate wetland system

2005 ◽  
Vol 51 (9) ◽  
pp. 165-171 ◽  
Author(s):  
S. Wallace ◽  
R. Kadlec
Keyword(s):  
Pilot Scale ◽  
Full Scale ◽  
Cold Climate ◽  
System A ◽  
Degradation Rates ◽  
Mass Load ◽  
Hydraulic Load ◽  
In Series ◽  
Benzene Toluene ◽  
Wetland System

A pilot-scale subsurface vertical-flow wetland system was constructed at the former BP Refinery in Casper, Wyoming in order to determine benzene, toluene, ethylbenzene and xylene (BTEX) degradation rates in a cold-climate application. The pilot system, consisting of 4 cells, each dosed at a nominal flow rate of 5.4 cubic metres per day, was operated between August and December 2002. The pilot tested the effects of wetland mulch and aeration on system performance. Areal rate constants (kA values) were calculated based on an assumed three tanks in series (3TIS). The presence of wetland sod and aeration both improved treatment performance. Mean kA values were 244 m/yr for cells without sod or aeration, and improved to 356 m/yr for cells with sod and aeration. Based on the results of the pilot system, a full-scale wetland system (capable of operating at 6,000 m3/day) was started up in May 2003. The full-scale system achieved permit compliance within one week of startup, but is currently being loaded at only 45% of the design hydraulic load, and 15% of the design BTEX mass load, resulting in a mean kA value of ∼350 m/yr.

scholarly journals A Compound Current Limiter and Circuit Breaker

Electronics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 551 ◽  
Author(s):  
Amir Heidary ◽  
Hamid Radmanesh ◽  
Ali Bakhshi ◽  
Kumars Rouzbehi ◽  
Edris Pouresmaeil
Keyword(s):  
Voltage Drop ◽  
Circuit Breaker ◽  
Experimental Results ◽  
Fault Current ◽  
Fault Current Limiter ◽  
System A ◽  
Ability To Act ◽  
Compound Type ◽  
In Series ◽  
Current Limiter

The protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter and circuit breaker (CLCB) which can limit fault current and fast break to adjust voltage sags at the protected buses. In addition, it can act as a circuit breaker to open the faulty line. The proposed CLCB is based on a series L-C resonance, which contains a resonant transformer and a series capacitor bank. Moreover, the CLCB includes two anti-parallel power electronic switches (a diode and an IGBT) connected in series with bus couplers. In order to perform an analysis of CLCB performance, the proposed structure was simulated using MATLAB. In addition, an experimental prototype was built, tested, and the experimental results were reported. Comparisons show that experimental results were in fair agreement with the simulation results and confirm CLCB’s ability to act as a fault current limiter and a circuit breaker.

RELIABILITY MEASURES OF A COLD STANDBY SYSTEM WITH PREVENTIVE MAINTENANCE AND REPAIR

2013 ◽  
Vol 20 (06) ◽  
pp. 1350022 ◽  
Author(s):  
S. C. MALIK ◽  
SUDESH K. BARAK
Keyword(s):  
Preventive Maintenance ◽  
Failure Time ◽  
Reliability Measures ◽  
Maintenance And Repair ◽  
Regenerative Point ◽  
Cold Standby ◽  
Semi Markov Process ◽  
Standby System ◽  
Regenerative Point Technique ◽  
Negative Exponential

The purpose of the present study is to determine reliability measures of a two-unit cold standby system with preventive maintenance and repair. The units are identical in nature subject to constant failure from normal mode. Preventive maintenance of the operative unit is carried out after a pre-specific time "t" up to which no failure occurs. However, repair of the unit is done at its failure. The unit works as new after repair and preventive maintenance. The switch devices are perfect. The distributions of failure time and the time by which unit undergoes for preventive maintenance are taken as negative exponential while that of preventive maintenance and repair times are assumed as arbitrary with different probability density functions. The random variables associated with failure, preventive maintenance and repair times are statistically independent. The semi-Markov process and regenerative point technique are adopted to derive the expressions for system performance measures in steady state. The graphical behavior of MTSF, availability and profit function have been observed with respect to preventive maintenance rate for particular values of other parameters and costs.

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