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Tytuł:
Computer simulation as one of the tools for modelling of the work cycle of loading and transport of the raw material at a quarry
Autorzy:
Šaderová, Janka
Ambriško, Ľubomír
Powiązania:
https://bibliotekanauki.pl/articles/1402314.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
modelling
simulation
process
work cycle
loading
transport
Opis:
The article deals with the modelling of the technological process at a quarry. The process modelling was carried out applying the simulation. The analysis of the operations performed within the technological process was used as the basis for the creation of the simulation model in the ExtendSim simulation software. The model simulation consisted of two parts. The first part represented the work cycle of a lorry – loading the lorry, a journey with the loaded material, emptying the load and a journey back to the loading station. The second part represented the work cycle of a loader that loads the material onto the lorry. The designed model was used to carry out several experiments. The article presents the results of two experiments. The simulation experiments were carried out for two different simulated times; the simulated time of 1 hour and the simulated time of 7.5 hours, representing 1 work shift. The results of the simulation comprised several parameters of time- and operation-related indicators. The presented simulation model is an appropriate accessory tool for the decision-making process when designing new systems or assessing the existing ones.
Źródło:
Mining Science; 2020, 27; 199-209
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ergonomiczna analiza ryzyka w oparciu o cykl czasowy pracy operatora - studium przypadku
Ergonomic risk analysis based on the operators work cycle - a case study
Autorzy:
Lasota, Andrzej Marek
Powiązania:
https://bibliotekanauki.pl/articles/27323742.pdf
Data publikacji:
2023
Wydawca:
STE GROUP
Tematy:
ergonomia
ryzyko
OWAS
cykl pracy
ergonomics
risk
work cycle
Opis:
Pracownicy są istotną częścią systemu produkcyjnego i wykonują różnorodne prace i zadania. Pracy wykonywanej przez operatorów towarzyszy ergonomiczne ryzyko wystąpienia zaburzeń mięśniowo-szkieletowych (ZMSz). ZMSz u pracowników w związku z wykonywaną pracą zawodową są nadal powszechnym zjawiskiem w przemyśle. ZMSz prowadzą do zakłóceń w procesach produkcji, absencji chorobowej oraz generują dodatkowe koszty dla przedsiębiorstw. W artykule przedstawiono ergonomiczną analizę ryzyka narażenia operatora na ZMSz w oparciu o studium przypadku. Do oceny ryzyka zastosowano metodę OWAS. Ocenę wykonano na stanowisku wykrawania arkuszy blach. Praca posiadała charakter powtarzalny i charakteryzowała się cyklem czasowym operatora. Wyniki pokazały, że operator ponad 28% efektywnego czasu pracy przebywa w szkodliwych i bardzo szkodliwych pozycjach pracy, z dużym oraz bardzo dużym ryzykiem powstania zaburzeń w układzie mięśniowo-szkieletowym. Sformułowano rekomendacje obejmujące zmiany w strukturze przestrzennej stanowiska pracy, przeprowadzenie szkoleń pracowników z podstaw ergonomii stanowiska pracy oraz prawidłowych pozycji podczas pracy.
Workers are an essential part of the production system and perform a variety of jobs and tasks. The work performed by operators is accompanied by an ergonomic risk of developing musculoskeletal disorders (MSDs). MSDs are still common phenomenon in industry. And MSDs lead to disruptions in production processes, sickness absence and additional costs for businesses. The article presents an ergonomic risk analysis of operator exposure to MSDs based on a case study. The OWAS method was used for risk assessment. The evaluation was performed at the sheet metal punching station. The task was repetitive and characterized by the operator's work cycle. The results showed that the operator spends more than 28% of the effective working time in harmful and very harmful working postures, with a high and very high risk of developing musculoskeletal disorders. Recommendations were formulated, including changes in the layout of the workplace, training employees on the principles of ergonomics and correct working postures.
Źródło:
Systemy Wspomagania w Inżynierii Produkcji; 2023, 12, 2; 1--8
2391-9361
Pojawia się w:
Systemy Wspomagania w Inżynierii Produkcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Upper Limb Load as a Function of Repetitive Task Parameters: Part 1 - A Model of Upper Limb Load
Autorzy:
Roman-Liu, D.
Powiązania:
https://bibliotekanauki.pl/articles/90123.pdf
Data publikacji:
2005
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
external load
upper limb
handgrip force
cycle work
repetitive task parameters
praca powtarzalna
obciążenie fizyczne
kończyna górna
siła mięśni
obciążenie pracą
Opis:
The aim of the study was to develop a theoretical indicator of upper limb musculoskeletal load based on repetitive task parameters. As such the dimensionless parameter, Integrated Cycle Load (ICL) was accepted. It expresses upper limb load which occurs during 1 cycle. The indicator is based on a model of a repetitive task, which consists of a model of the upper limb, a model of basic types of upper limb forces and a model of parameters of a repetitive task such as length of the cycle, length of periods of the cycle and external force exerted during each of the periods of the cycle. Calculations of the ICL parameter were performed for 12 different variants of external load characterized by different values of repetitive task parameters. A comparison of ICL, which expresses external load with a physiological indicator of upper limb load, is presented in Part 2 of the paper.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2005, 11, 1; 93-102
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive jet engines work analysis and control
Autorzy:
Kowalski, M.
Powiązania:
https://bibliotekanauki.pl/articles/242121.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
adaptation engine
parameters of the engine air
sensitivity of work cycle
Opis:
The paper describes major designs of adaptive jet engines as well as their structural and operational advantages. Attention is paid to actual thermodynamic cycles of such engines and energy balance of flows. Particular attention paid to a double-rotor engine designed by Pratt & Whitney, where a portion of air is bled from downstream of the compressor and then supplied to the area downstream the turbine when the engine is operated at its maximum performance (turbine bypass engine). Then attention is paid to actual thermodynamic cycles of such engines and energy balance of flows. It was shown that real working cycles of these engines represent figures with variable surface areas, which is the reason for the second name of these units - engines with variable thermodynamic cycle. It is explained how basic parameters of such engines affect sensitiveness of operating cycles and controllability. The analysis has been conducted separately for internal and external channel. The sensitivity analysis for the working cycle makes it possible to select parameters that are potentially controllable and adjustable. To sum up the foregoing deliberations one has to state that operation of turbojet adaptive engines is the topic that needs much more investigation. Even the design solution of the engine itself, although being really exciting and promising, is troublesome in the aspects of the design and process engineering, and will lead to a series of operation and maintenance problems.
Źródło:
Journal of KONES; 2011, 18, 2; 225-234
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The analysis of the usability of selected stationary load cycles for the assessment of the tractor engine economy
Analiza przydatnosci wybranych stacjonarnych cykli obciazen dla oceny ekonomicznosci silnikow ciagnikow
Autorzy:
Sedlak, P.
Janicki, W.
Matuszak, K.
Powiązania:
https://bibliotekanauki.pl/articles/793679.pdf
Data publikacji:
2012
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
combustion engine
operating index
engine
road vehicle
engine speed
fuel consumption
engine work cycle
tractor engine
stationary load cycle
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2012, 12, 1
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizacija sostava smesi pri regulirovanii moshhnosti benzinovogo dvigatelja metodom otkljuchenija rabochikh ciklov
Optimization of fuel mixture in regulation of power of gasoline engine by method of cut-off of working cycles
Autorzy:
Gerasimchuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/76641.pdf
Data publikacji:
2014
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
petrol engine
engine capacity
work cycle
switching
exhaust gas
electromagnetic valve
mathematical model
nitrogen oxide
ecological indicator
Źródło:
Motrol. Motoryzacja i Energetyka Rolnictwa; 2014, 16, 3
1730-8658
Pojawia się w:
Motrol. Motoryzacja i Energetyka Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dobór środków transportowych dla gospodarstwa przy pomocy programu "Agregat - 2"
Selecting the means of transport for the farmstead using the program "Agregat - 2"
Autorzy:
Cupiał, M.
Kuboń, M.
Powiązania:
https://bibliotekanauki.pl/articles/289785.pdf
Data publikacji:
2005
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
technika rolnicza
program komputerowy
mechanizacja
transport
cykl pracy
wydajność
agricultural engineering
computer program
mechanization
work cycle
performance
Opis:
Przedstawiono autorski program komputerowy "Agregat-2" służący do wyliczania wydajności agregatów transportowych. Program pozwala na wyliczenie cyklu pracy środka transportowego pracującego w różnych warunkach. Zastosowanie programu może ułatwić dobór środków transportowych dla gospodarstwa.
The paper presents the authoring computer program "Agregat-2" intended for calculation of transport unit performance. The program enables calculation of work cycle of the mean of transport working under different conditions. Application of the program may facilitate selection of the means of transport for the farmstead.
Źródło:
Inżynieria Rolnicza; 2005, R. 9, nr 14, 14; 69-74
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The evaluation of the Fiat 0.9 TwinAir engine powered by petrol and LPG gas work cycles uniqueness
Autorzy:
Lejda, K.
Kurczyński, D.
Łagowski, P.
Warianek, M.
Dąbrowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/245074.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark ignition engines
gas engines
gasoline engines
uniqueness of work cycle of internal combustion engine
indicator diagram
Opis:
The article describes the test results of the uniqueness of the work cycle of two-cylinder internal combustion piston FIAT 0.9 TwinAir engine, while being powered by 95 octane petrol fuel and LPG gas. The engine was working according to load characteristics. The engine mounted on the test bench was equipped with a sequential LPG gas fuel supply system. The gas fuels differ significantly from the petrol fuels in their physiochemical properties. In order to rationally utilize gas fuels to power internal combustion engines, the knowledge about basic fuel burning process of these fuels is required. The article shows the analysis of individual engine work cycles of the technologically advanced engine in order to evaluate the influence of powering by LPG gas fuel on the rate of uniqueness of its work cycles. The measure of uniqueness of the inter-cylinder processes are the work cycle uniqueness indicators, which are as follows: the maximum work cycle pressure uniqueness indicator, the average measured work cycle pressure uniqueness indicator, the measured pressure work cycle graph uniqueness indicator and the measured pressure work cycle partial graph uniqueness. The carried out research and its analysis has shown that powering the engine with LPG gas has an influence on the engine work cycles and its uniqueness. The burning process of the mixture consisting of air and LPG gas is quicker, which has an effect on the higher speed of pressure increase rate in comparison with the engine being powered by petrol fuel. Achieved maximum in-cylinder pressure values while the engine was powered by LPG gas were higher in comparison with it being fuelled with conventional fuel. This causes an increase of the gas lads on crank-piston system, which are influencing directly the piston with higher heat load, and the thermal load of the engine.
Źródło:
Journal of KONES; 2018, 25, 3; 323-330
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computational domain discretization and its impact on flow field around the spark plug in SI engine
Dyskretyzacja domeny obliczeniowej i jej wplyw na pole przeplywu wokol swiecy zaplonowej w silniku niskopreznym
Autorzy:
Sosnowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/792239.pdf
Data publikacji:
2011
Wydawca:
Komisja Motoryzacji i Energetyki Rolnictwa
Tematy:
spark ignition engine
numerical modelling
mesh type
computational domain discretization
computational fluid dynamics
spark plug
combustion chamber
work cycle
Źródło:
Teka Komisji Motoryzacji i Energetyki Rolnictwa; 2011, 11C
1641-7739
Pojawia się w:
Teka Komisji Motoryzacji i Energetyki Rolnictwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromyographic Analysis of a Repetitive Hand Gripping Task
Autorzy:
Cook, T.
Rosecrance, J.
Zimmermann, C.
Gerleman, D.
Ludewig, P.
Powiązania:
https://bibliotekanauki.pl/articles/91061.pdf
Data publikacji:
1998
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
electromyography
cumulative trauma disorders
work-rest cycle
muscle force
hand gripping
elektromiografia
siła mięśni
cykl pracy
kończyna górna
Opis:
Electromyography (EMG) has been proposed as a method for determining muscle effort in repetitive upper limb tasks, which are often related to cumulative trauma disorders. EMG activity of the finger flexor musculature was investigated during a repetitive hand gripping task having 5 different cycle durations (2 to 6 s), various percentage of work time (and rest) within the work cycle (20% to 80%), and 3 different grip force levels. Thirty healthy adult participants each performed 27 randomly ordered 30-s repetitive hand gripping trials as well as 3 isometric contractions, which were used to normalize data from the hand gripping trials. There was a significant decrease in mean EMG as the duration of the work-rest cycle time increased. At each force level, EMG increased as the percentage of work time within the work-rest cycle increased, but to a greater extent at the highest force level. The results of this study suggest that overall muscle effort, and perhaps muscle fatigue, can be reduced most effectively by modifying the force requirements of the repetitive task. Other variables, such as the percentage of work time within a cycle and overall work cycle time have less effect on the EMG activity level. The results of this study have implications for developing strategies to reduce muscle fatigue during repetitive hand gripping tasks in an effort to reduce the effects of cumulative trauma disorders.
Źródło:
International Journal of Occupational Safety and Ergonomics; 1998, 4, 2; 185-198
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The DMAIC cycle in managing the development of work potential in service enterprise
Autorzy:
Kowalik, Kamila
Powiązania:
https://bibliotekanauki.pl/articles/1075594.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
DMAIC cycle
management
work potential development
Opis:
The objective of the analysis conducted and described in this paper is to present the practical application of the DMAIC cycle in managing the development of work potential in service enterprise. The first part of the article contains the theoretical framework of work potential, its development, and the DMAIC methodology. Afterwards, based on the process approach to work potential development, practical application of the DMAIC cycle has been presented with using an anonymous survey to measure and analyze the problem, the 5Why method for finding the causes, and the Impact and Effort Matrix in improvement phase to choose the solutions worth implementing.
Źródło:
World Scientific News; 2019, 122; 206-217
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermodynamic calculation of a rotary engine with external heat supply based on the ideal rallis cycle
Autorzy:
Usenkov, Roman A.
Popov, Igor A.
Gortyshov, Yuri F.
Kokhanova, Svetlana Y.
Latypov, Ravil A.
Powiązania:
https://bibliotekanauki.pl/articles/2106207.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
thermodynamic calculation
ideal cycle
work
heat
external combustion engine
Opis:
The design and kinematic scheme of the operation of a rotary external combustion engine with offset shafts have been developed. Expressions are obtained that make it possible to calculate the values of the increasing and decreasing functions of the working volume of the hot and cold cavities with a change in the angle of rotation of the rotor. An expression is obtained for calculating the compression ratio in the cold cavity of a rotary heat engine with an external heat supply. An expression has been determined that makes it possible to calculate the total torque of a rotary external combustion engine. A comparative analysis of the torque values of a rotary heat engine with an external heat supply and a Wankel engine is carried out. An assessment of the efficiency of an external combustion engine with offset shafts is carried out. Based on the thermodynamic calculations using ideal Erickson and Rallis cycles for a rotary external combustion engine, the processes occurring inside the hot and cold cavities of a heat engine are described. The thermodynamic condition parameters at the characteristic points of the cycle are determined and expressions are obtained that determine the thermal efficiency of the ideal Erickson and Rallis cycles in relation to the considered external combustion engine. A method for calculating the ideal cycle for an external combustion engine with offset shafts is presented.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 1; 40--47
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Possibility of the charge exchange work diminishing of an internal combustion engine in part load
Autorzy:
Postrzednik, S.
Żmudka, Z.
Powiązania:
https://bibliotekanauki.pl/articles/247156.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
engine efficiency
charge exchange work
engine load
valve actuating
thermodynamic cycle
Opis:
Internal combustion engines, used for driving of different cars, occur not only at the full load, but mostly at the part load. The relative load exchange work at the full (nominal) engine load is significant low. At the part load of the IC engine his energy efficiency r)e is significantly lower than in the optimal (nominal field) range of the performance parameters. One of the numerous reasons of this effect is regular growing of the relative load exchange work of the IC engine. The load exchange work of IC engine essentially determines the effective engine efficiency. It is directly connected with the quantitative regulation method common used in the IC engines. From the thermodynamic point of view - the main reason of this effect is the throttling process (causing exergy losses) occurring in the inlet and outlet channels. The known proposals for solving of this problem are based on applying of the fully electronic control of the motion of inlet, outlet valves and new reference cycles. The independent actuating (steerage) procedures of the ICE inlet valves should assure the adequate mass of the fresh charge, while procedures of the outlet valves are focused on the optimal exhaust gas recirculation rate, according to the engine load. The idea presented in the paper leads to diminishing the charge exchange work of the IC engines. The mentioned above problem can be solved using presented in the paper a new concept of the reference cycle (called as eco-cycle) of IC engine.
Źródło:
Journal of KONES; 2011, 18, 4; 377-387
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fatigue alters the biomechanical contribution of lower extremity joints during a stretch-shortening cycle task
Autorzy:
Sun, Xiaole
Xia, Rui
Zhang, Ximi
Zhen, Luo
Fu, Weijie
Powiązania:
https://bibliotekanauki.pl/articles/949743.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
skoki
zmęczenie
sztywność
stretch-shortening cycle
drop jump
fatigue
stiffness
joint work
Opis:
This study aimed to explore the effect of fatigue on the biomechanical contribution of the lower extremity joints during a typical stretch-shortening cycle (SSC) task. Methods: 15 male athletes completed drop jump (DJ) under pre- and post-fatigue. Vicon motion capture system and 3D Kistler force plates were used to collect kinematics and ground reaction force data simultaneously. Results: Under fatigue condition, 1) the DJ height decreased; the touchdown angle of knee and ankle reduced and the range of motion increased; 2) the maximum push-off moment and power of knee was reduced; 3) the stiffness of knee, ankle, and legs was reduced; 4) the energy generation and the net energy of the ankle decreased; 5) the energy contribution of knee decreased during the eccentric phase. Conclusions: Fatigue altered biomechanical contribution of the lower extremity joints by changing the movement pattern during DJ. The control ability of the knee and ankle were decreased. Eventually, the jump performance was reduced. In addition, the decrease of stiffness as well as the energy contribution of these joints can be used as sensitive indices to evaluate the performance of DJ after fatigue.
Źródło:
Acta of Bioengineering and Biomechanics; 2019, 21, 2; 11-19
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The rationalization of automatic units for HPDC technology
Autorzy:
Herman, A.
Powiązania:
https://bibliotekanauki.pl/articles/382755.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
automatyka w odlewnictwie
robotyka w odlewnictwie
zarządzanie jakością
odlewanie wysokociśnieniowe
cykl pracy
automation in foundry
robotics in foundry
quality management
high pressure die casting (HPDC)
work cycle
rationalization of automatic unit
Opis:
The paper deals with problem of optimal used automatic workplace for HPDC technology - mainly from aspects of operations sequence, efficiency of work cycle and planning of using and servicing of HPDC casting machine. Presented are possible ways to analyse automatic units for HPDC. The experimental part was focused on the rationalization of the current work cycle time for die casting of aluminium alloy. The working place was described in detail in the project. The measurements were carried out in detail with the help of charts and graphs mapped cycle of casting workplace. Other parameters and settings have been identified. The proposals for improvements were made after the first measurements and these improvements were subsequently verified. The main actions were mainly software modifications of casting center. It is for the reason that today's sophisticated workplaces have the option of a relatively wide range of modifications without any physical harm to machines themselves. It is possible to change settings or unlock some unsatisfactory parameters.
Źródło:
Archives of Foundry Engineering; 2012, 12, 2; 29-34
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł

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