Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "wydajnosc" wg kryterium: Temat


Tytuł:
Effects of Specific Fuel Consumption and Exhaust Emissions of Four Stroke Diesel Engine with CuO/Water Nanofluid as Coolant
Autorzy:
Senthilraja, S.
Vijayakumar, K. C. K.
Gangadevi, R.
Powiązania:
https://bibliotekanauki.pl/articles/140023.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanofluid
engine performance
exhaust emissions
nanopłyn
wydajność silnika
emisja spalin
Opis:
This article reports the effects of CuO/water based coolant on specific fuel consumption and exhaust emissions of four stroke single cylinder diesel engine. The CuO nanoparticles of 27 nm were used to prepare the nanofluid-based engine coolant. Three different volume concentrations (i.e 0.05%, 0.1%, and 0.2%) of CuO/water nanofluids were prepared by using two-step method. The purpose of this study is to investigate the exhaust emissions (NOx), exhaust gas temperature and specific fuel consumption under different load conditions with CuO/water nanofluid. After a series of experiments, it was observed that the CuO/water nanofluids, even at low volume concentrations, have a significant influence on exhaust emissions. The experimental results revealed that, at full load condition, the specific fuel consumption was reduced by 8.6%, 15.1% and 21.1% for the addition of 0.05%, 0.1% and 0.2% CuO nanoparticles with water, respectively. Also, the emission tests were concluded that 881 ppm, 853 ppm and 833 ppm of NOx emissions were observed at high load with 0.05%, 0.1% and 0.2% volume concentrations of CuO/water nanofluids, respectively.
Źródło:
Archive of Mechanical Engineering; 2017, LXIV, 1; 111-121
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy consumption modeling of processes in the automated manufacturing systems
Autorzy:
Honczarenko, J.
Berliński, A.
Powiązania:
https://bibliotekanauki.pl/articles/407311.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
proces produkcji
energochłonność
wydajność ekonomiczna
energy consumption
manufacturing process
saving energy
Opis:
High-tech manufacturing such as machining at high speeds, laser, electrical discharge machining are highly energy intensive. Automation of assistant processes such as transport, storage, quality control also causes increasing of energy consumption. In this context, important is estimating and minimize the volume used energy. The main contribution of paper is the evaluation method of energy production processes in automated production systems, based on the equation energy formulation. Simple calculation energy consumption example was also presented for elementary transport operations in a high storage depot. Implantation this method enables rating power consumption of manufacturing process on design stage where used are technical subsystems such as: machines, conveyors, manipulators etc. Designing processes with power rating consumption enable saving energy in manufacturing processes that is important for their economic efficiency.
Źródło:
Management and Production Engineering Review; 2012, 3, 1; 92-96
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative analysis of selected models of water coning in gas reservoirs
Analiza porównawcza wybranych modeli powstawania stożków wodnych w złożach gazowych
Autorzy:
Smulski, R.
Powiązania:
https://bibliotekanauki.pl/articles/219305.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powstawanie stożków wodnych
wydajność krytyczna gazu
water coning
critical gas rate
Opis:
Exploitation of natural gas fields with edge or underlying water is usually defined per analogy to the oil fields. The existing models do not correspond to reality as they do not describe relevant processes related with a turbulent gas flow near the well. The natural gas exploitation with productivity greater than critical may be advantageous in view of summaric depletion and rate of depletion. Article presents: the analysis of the selected critical rates models, determining the influence of specific parameters on the critical rate values, introducing new modified formula for critical rates, and comparative calculations for various configurations with the numerical model.
Problem eksploatacji złóż gazu ziemnego z wodą podścielającą lub okalającą jest określany zwykle na podstawie analogii ze złożami ropnymi. Istniejące modele nie odpowiadają rzeczywistości, ponieważ nie opisują istotnych procesów związanych z turbulentnym przepływem gazu w pobliżu odwiertu. Równocześnie eksploatacja gazu z wydajnością większą od krytycznej może być korzystna z punktu widzenia sumarycznego sczerpania złoża oraz szybkości jego sczerpania. W artykule przedstawiono: analizę wybranych modeli wydajności krytycznej, określenie wpływu poszczególnych parametrów na wartości wydajności krytycznych, wprowadzenie nowych zmodyfikowanych formuł określających wydajności krytyczne oraz przeprowadzenie obliczeń porównawczych dla różnych konfiguracji z wykorzystaniem modelu numerycznego.
Źródło:
Archives of Mining Sciences; 2012, 57, 2; 451-470
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exergetic Analysis For A Complete Node Of Fluidised-Bed Drying Of Poppy Seeds
Autorzy:
Skoneczna-Łuczków, J.
Ciesielczyk, W.
Powiązania:
https://bibliotekanauki.pl/articles/185488.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fluidised drying
efficiency
exergy
poppy seed
suszenia fluidalnego
wydajność
egzergia
Opis:
The article presents an experimental-theoretical analysis of fluidised-bed drying of poppy seeds directed on minimisation of energy. The analysis was performed for a complete drying node incorporating a heat exchanger and a fan. Two complementary factors were used in the exergetic evaluation: exergy efficiency and unit consumption of exergy. An analysis of drying in stationary bed was carried out for comparison purposes. Results of the exergetic analysis can become a basis for innovative works focused on decreasing energy consumption of a technological node being analysed, e.g. by the use of recirculation of fluidising-drying medium.
Źródło:
Chemical and Process Engineering; 2015, 36, 4; 437-447
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and experimental study of armour system consisted of ceramic and ceramic- elastomer composites
Autorzy:
Chabera, P.
Boczkowska, A.
Morka, A.
Niezgoda, T.
Oziębło, A.
Witek, A.
Powiązania:
https://bibliotekanauki.pl/articles/200348.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ballistic performance
numerical simulation
ceramic
wydajność balistyczna
symulacja numeryczna
ceramiczny
Opis:
The paper presents numerical and experimental results in the study of composite armour systems for ballistic protection. The modelling of protective structures and simulation methods of experiment as well as the finite elements method were implemented in LS DYNA software. Three armour systems with different thickness of layers were analyzed. Discretization for each option was built with three dimensional elements guaranteeing satisfactory accuracy of the calculations. Two selected armour configurations have been ballistically tested using the armour piercing (AP) 7.62 mm calibre. The composite armour systems were made of Al2O3 ceramics placed on the strike face and high strength steel as a backing material. In case of one ballistic structure system an intermediate ceramic- elastomer layer was applied. Ceramic- elastomer composites were obtained from porous ceramics with porosity gradient using pressure infiltration of porous ceramics by elastomer. The urea-urethane elastomer, as a reactive liquid was introduced into pores. As a result composites, in which two phases were interconnecting three-dimensionally and topologically throughout the microstructure, were obtained. Upon ballistic impact, kinetic energy was dissipated by ceramic body The residual energy was absorbed by intermediate composite layer. Effect of the composite shell application on crack propagation of ceramic body was observed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 4; 853-859
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of performance of diamond wire saw with respect to texture characteristics of rock
Prognozowanie wydajności pracy strunowej piły diamentowej w odniesieniu do charakterystyki tekstury skał
Autorzy:
Ghaysari, N.
Ataei, M.
Sereshki, F.
Mikaiel, R.
Powiązania:
https://bibliotekanauki.pl/articles/220178.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strunowa piła diamentowa
wydajność pracy
tekstura
diamond wire saws
production rate
texture coefficient
Opis:
In this study, prediction of production rate in diamond wire saw has been investigated. Performance measurements of diamond wire saw carried out in 7 different quarries of carbonate rocks in Iran. For determination textural properties, rock samples were collected from these quarries. At first, a thin section was prepared for each rock and then 5 digital photographs were taken from each section. After this, all images were digitized using AutoCAD software. Then, area, perimeter, longest diameter and shortest diameter were assigned. According to these parameters, all of the other textural characteristics and texture coefficient were determined too. The correlation between sawing rate and textural characteristics were evaluated using multiple and simple regression analyses. Then developed model was validated by P-value test. It was concluded that area, perimeter, diameter equivalent and index of grain size homogeneity are very effective on production rate. Production rate using diamond wire saw can reliably be predicted using developed model.
W pracy prognozowano wydajność pracy strunowej piły diamentowej. Badania wydajności prowadzono w 7 kamieniołomach na terenie Iranu, w których wydobywane są skały węglanowe. W celu określenia tekstury skał zebrano próbki wszystkich skał wydobywanych w kamieniołomach. Przygotowano zgłady i wykonano 5 fotografii cyfrowych każdej analizowanej próbki. Uzyskane obrazy poddano następnie obróbce cyfrowej przy użyciu oprogramowania AutoCAD. Określono następujące parametry: powierzchnia, obwód, najdłuższa i najkrótsza średnica. W oparciu o powyższe parametry przeprowadzono analizę tekstury i wyznaczono odpowiednie współczynniki. Korelację pomiędzy wydajnością pracy piły a właściwościami powierzchni (teksturą) określono przy użyciu prostej regresji liniowej oraz regresji wielokrotnej. Otrzymany model poddano następnie walidacji przy pomocy odpowiednich testów statystycznych. Stwierdzono, że pole powierzchni, obwód, równoważne średnice oraz wskaźnik jednorodności uziarnienia mają wpływ na wydajność pracy piły. Opracowany model może być skutecznie wykorzystywany dla wiarygodnego prognozowania postępu prac prowadzonych z wykorzystaniem piły diamentowej.
Źródło:
Archives of Mining Sciences; 2012, 57, 4; 887-900
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Design Features of Compressor Casing Treatment
Badanie charakterystyk projektowych obróbki obudowy kompresora
Autorzy:
Nezym, V
Powiązania:
https://bibliotekanauki.pl/articles/950694.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
axial compressor
stall range
efficiency
casing treatment
grooves
kompresor
rowki obwodowe
wydajność
Opis:
Casing treatment in the form of circumferential grooves over a rotor blade tips is used for improvement of an axial compressor performance. Usually, these grooves extend compressor’s stall range (stable operational range) but decrease its efficiency. In the paper, there are presented main results of investigations on grooves that influence positively efficiency of compressor. There were investigated traditional (typical) and newly developed groove configurations. Certain grooves combine increase in efficiency with extension in stall range.
Obróbka obudowy kompresora, polegajacą na wykonaniu obwodowych rowków ponad szczytem łopaty wirnika, jest stosowana dla poprawy własciwosci roboczych kompresora. Zwykle rowki takie zwiekszaja zakres przeciagania kompresora (zakres stabilnego działania), ale pogarszaja sprawność. W artykule zaprezentowano główne wyniki badan nad rowkami, które wpływaja pozytywnie na sprawnosc kompresora. Badano zarówno tradycyjne (typowe) konfiguracje rowków, jak i konfiguracje ostatnio opracowane. Niektóre z nich zapewniają zarówno wzrost sprawności jak zakresu przeciągania.
Źródło:
Archive of Mechanical Engineering; 2014, LXI, 1; 153-161
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The influence of external cooling system on the performance of supercritical steam turbine cycles
Autorzy:
Kosman, W.
Powiązania:
https://bibliotekanauki.pl/articles/240233.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
para nadkrytyczna
schładzanie
turbina parowa
wydajność
cooling
efficiency
steam turbine
supercritical steam
Opis:
The problem presented in this paper refers to the concepts applied to the design of supercritical steam turbines. The issue under the investigation is the presence of a cooling system. Cooling systems aim to protect the main components of the turbines against overheating. However the cooling flows mix with the main flow and modify the expansion line in the steam path. This affects the expansion process in the turbine and changes the performance when compared to the uncooled turbine. The analysis described here investigates the range of the influence of the cooling system on the turbine cycle. This influence is measured mainly through the change of the power generation efficiency. The paper explains the approach towards the assessment of the cooling effects and presents results of the modeling for three supercritical steam cycles.
Źródło:
Archives of Thermodynamics; 2010, 31, 3; 131-144
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of start energy of Stirling engine type alpha
Autorzy:
Kropiwnicki, Jacek
Powiązania:
https://bibliotekanauki.pl/articles/240606.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Stirling engines
system efficiency
low temperature supply
silniki Sterlinga
wydajność systemu
zasilanie
niska temperatura
Opis:
The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.
Źródło:
Archives of Thermodynamics; 2019, 40, 3; 243-259
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of moisture content of combusted wood on the thermal efficiency of a boiler
Autorzy:
Dzurenda, L.
Banski, A.
Powiązania:
https://bibliotekanauki.pl/articles/239999.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
boiler
wood
combustion
thermal efficiency
mathematical dependence
bojler
drewno
spalanie
wydajność termiczna
matematyczna zależność
Opis:
In the paper the influence of moisture content of wood on the heat losses and thermal efficiency of a boiler is analysed. The moisture content of wood has a negative effect, especially on flue gas loss. The mathematical dependence of the thermal efficiency of a boiler is presented for the following boundary conditions: the moisture content of wood 10–60%, range of temperatures of emitted flue gases from the boiler into the atmosphere 120–200 C, the emissions meeting the emission standards: carbon monoxide 250 mgm-3, fly ash 50 mgm-3 and the heat power range 30–100%.
Źródło:
Archives of Thermodynamics; 2017, 38, 1; 63-74
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical thermodynamic optimization of supercritical coal fired power plant with support of IPSEpro software
Autorzy:
Elsner, W.
Kowalczyk, Ł.
Marek, M.
Powiązania:
https://bibliotekanauki.pl/articles/240118.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
optymalizacja termodynamiczna
siłownia nadkrytyczna
symulacja
wydajność
efficiency
simulation
supercritical power plant
thermodynamic optimization
Opis:
The paper presents a thermodynamic optimization of supercritical coal fired power plant. The aim of the study was to optimize part of the thermal cycle consisted of high-pressure turbine and two chosen high-pressure feed water heaters. Calculations were carried out using IPSEpro software combined with MATLAB, where thermal efficiency and gross power generation efficiency were chosen as objective functions. It was shown that the optimization with newly developed framework is sufficiently precise and its main advantage is the reduction of computation time on comparison to the classical method. The calculations have shown the tendency of the increase in efficiency, with the rise of a number of function variables.
Źródło:
Archives of Thermodynamics; 2012, 33, 3; 101-110
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Filling model for the working multi-disc biomass grain grinding unit
Model wypełnienia zespołu roboczego, wielotarczowego rozdrabniacza ziaren biomasy
Autorzy:
Tomporowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/139718.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rozdrabnianie
rozdrabniacz wielotarczowy ziaren biomasy
biomasa
wydajność
grinding
multidisc biomass grain grinding unit
biomass
efficiency
Opis:
Efficiency, functionality and performance of the grain grinding process are significantly influenced by phenomena that are difficult to describe and occur in the working area of the grinder. In a machine-based, multi-disc grinding of grain biomaterials, the design of the quasi-cutting unit, volumes, sections of transport/grinding holes, their motion and the design features of the discs (the grinding unit) must facilitate the functions of grinding in the inter-hole space (with minimum energy-consumption of the process and maximum efficiency) and minimising undesirable phenomena related to mixing and transport. The pre-requisite for optimisation of the quasi-cutting unit design is a mathematical model. Among many aspects of the problem, this study describes a sample procedure resulting in a filling model for a biomass grain quasi-cutting unit including an initial verification of the same under conditions of the evaluation of maize and triticale grain grinding efficiency, using an innovative multi-hole 5-disc and 7-disc grinder.
Istotny wpływ na wydajność, funkcjonalność i sprawność procesu rozdrabniania ziaren zbóż mają trudne do opisania zjawiska, zachodzące w przestrzeni roboczej rozdrabniacza. W maszynowym wielotarczowym rozdrabnianiu biomateriałów ziarnistych, należy tak dobrać konstrukcję zespołu quasi-ścinającego, objętości, przekroje otworów transportowo-rozdrabniających, ich ruch i cechy konstrukcyjne tarcz (zespołu rozdrabniającego), aby zostały zrealizowane założone funkcje: rozdrabnianie w przestrzeni międzyotworowej (przy minimalnej energochłonności procesu i maksymalnej wydajności) oraz minimalizacja zjawisk niepożądanych związanych z mieszaniem i transportem. Warunkiem optymalizacji konstrukcji zespołu quasi-ścinającego jest model matematyczny. Wśród wielu warstw problemu, w pracy przedstawiono przykładowe postępowanie, prowadzące do modelu wypełnienia zespołu quasi-ścinającego ziarna biomasy wraz z wstępną jego weryfikacją w warunkach badania wydajności rozdrabniania ziaren kukurydzy i pszenżyta na innowacyjnym rozdrabniaczu wielootworowym, 5-cio i 7-mio tarczowym.
Źródło:
Archive of Mechanical Engineering; 2012, LIX, 2; 155-174
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Savings in Foundries through Yield Improvement and Defect Reduction in Castings
Autorzy:
Chokkalingam, B.
Raja, V.
Dhineshkumar, M.
Priya, M.
Immanual, R.
Powiązania:
https://bibliotekanauki.pl/articles/382444.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
foundries
energy savings
casting yield
defective casting
melting
odlewnie
oszczędność energii
wydajność odlewania
wadliwe odlewy
topienie
Opis:
Energy conservation is an important step to overcome the energy crisis and prevent environmental pollution. Casting industry is a major consumer of energy among all the industries. The distribution of electrical energy consumed in all the departments of the foundry is presented. Nearly 70% of the energy is consumed especially in the melting department alone. Production of casting involves number of process variables. Even though lot of efforts has been taken to prevent defects, it occurs in the casting due to variables present in the process. This paper focuses the energy saving by improving the casting yield and by reducing the rejections. Furthermore an analysis is made on power consumption for melting in the induction furnace to produce defective castings and improvement in the casting yield. The energy consumed to produce defective castings in all other departments is also presented. This analysis reveals that without any further investment in the foundry, it is possible to save 3248.15 kWh of energy by reducing the rejections as well as by improving the casting yield. The redesign of the feeding system and the reduced major rejection shrinkage in the body casting improved the casting yield from 56% to 72% and also the effective yield from 12.89% to 66.80%.
Źródło:
Archives of Foundry Engineering; 2018, 18, 1; 15-18
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Critical performance attributes of Thai automotive supply chains
Autorzy:
Satayapaisal, A.
Takala, J.
Wiriyacosol, S.
Chansa-ngavej, C.
Powiązania:
https://bibliotekanauki.pl/articles/407337.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
przemysł motoryzacyjny
łańcuch dostaw
wydajność
supply chain performance
performance measurement
critical factor index
Thai automotive industry
Opis:
The Thai automotive industry has been ranked one of the top ten of the Thai export products for several years. Effective supply chain management has become a key strategy for the industry to stay competitive. Performance measurement has thus become a crucial issue in automotive supply chains. The purpose of the research is to gain insight into the relevant performance attributes that affect the automotive supply chains. The critical factor indexes (CFIs) are calculated in order to determine which of the performance attributes are considered to be the strength and which ones need to be specially focused, so that precautions could be made in developing the performance measurement system. Based on the CFIs, companies in Thai automotive supply chains can support their decision making under scarce resources with valid data. A set of questionnaires with different performance attributes is used comprising of two separate parts, one intended for the first tier supplier companies and the other for the automakers. Each performance attribute in the questionnaires is assessed on how important the company sees them from their perspective, how well the tasks measured by each performance attribute have been carried out in their companies, how they see themselves compared to their competitors, and how they see each performance attribute developing compared to the situation 1 to 2 years before. The results provide a guideline to the companies in Thai automotive supply chains to measure the right performance attributes for making the right decision in a competitive environment.
Źródło:
Management and Production Engineering Review; 2012, 3, 2; 36-48
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The method for increasing the efficiency of equipment’s maintenance in railway traction power supply systems
Autorzy:
Matusevych, O.
Kuznetsov, V.
Sychenko, V.
Powiązania:
https://bibliotekanauki.pl/articles/223664.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
railway traction
power systems
efficiency
maintenance equipments
traction substation
trakcja kolejowa
systemy zasilania
wydajność
konserwacja urządzeń
Opis:
Purpose. To develop the method for increasing the efficiency of the equipment’s maintenance and repair system, ensuring necessary level of operational reliability of the equipment, safety and reliability of the electric equipment with minimal expenses on operation. Relevance. Aging of the power equipment in railway power supply systems sharply raised a need for assessment of its states and degree of risk for operation outside rated service life. In critical conditions of technological processes and operational modes of the railways it is necessary to increase the equipment’s operational reliability. The scheduled maintenance and repair system whose main technical and economic criterion is the minimum of equipment’s downtimes on the basis of a rigid regulation of repair cycles, in the conditions of market regulations in the field of repair in many cases does not provide the optimal decisions due to insufficient financing. The solution of this problem is possible by improvement of the maintenance and repair system. Under these conditions the main direction for supporting the operational reliability of power electric equipment on TS is a development of the modern methods based on individual supervision over real changes of technical condition of power equipment. Scientific novelty. In this article the authors proposed an integrated approach, on the basis of which can be developed the effective maintenance and repair system for traction power supply systems. Proposed approach allowed to react quickly to changes of service conditions on traction substations, to control the technical condition of power electric equipment under the conditions of uncertainty, to establish interrelation between quality of service and operational reliability of the equipment, to choose a service strategy on traction substations. Practical importance. The validity of the developed method was confirmed by the results of calculations and practically by choosing the optimal maintenance's option for transformer TDTN-25000/150-70 U1 (ТДТН-25000/150-70 У1) on traction power supply substation.
Źródło:
Archives of Transport; 2018, 47, 3; 39-47
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Theory of Constraints as a Method of Results Optimization in Complex Organization
Autorzy:
Janosz, M.
Powiązania:
https://bibliotekanauki.pl/articles/382239.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
theory of constraints
optimization of production organization
foundry performance
teoria ograniczeń
organizacja produkcji
wydajność odlewni
Opis:
The paper presents the theory of constraints (TOC) as a method used to improve results in a complex, multiplants organization. In the article the assumptions of this method has been presented as well as iterative approach concerning how to launch it in practice. Main indicators for organizational effectiveness assessment have also been presented. The maximization of production assets utilization is a key issue for competitive organization in the changing market conditions. An appropriate usage of the theory of constraints enables efficient allocation of financial assets among particular plants within a capital group. An application of a method has been presented based on throughput analyses and its influence to improve financial results of one plant organization and synergy effect in multiplants organization. The theory of constraints can be used in almost every kind of business sectors, among them are metal and foundry industries. It allows to be implemented in production organizations as well as in any other company’s profiles. Everywhere the constraint has been defined there is a chance to achieve an improvement following the presented method. The examples have been taken from the casting plants which use continuous and mold casting technologies. The examples show that TOC approach can be successfully employed as the improvement tool of foundries’ performances.
Źródło:
Archives of Foundry Engineering; 2018, 18, 4; 59-64
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of different organic fluids on performances of binary slag washing water power plants
Autorzy:
Li, Z.
Liu, Y.
Dong, P.
Zhang, Y.
Xiao, S.
Powiązania:
https://bibliotekanauki.pl/articles/240438.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
slag washing water
efficiency
organic fluids
binary power cycle
wydajność
płyn organiczny
podwójny cykl zasilania
Opis:
In this paper, 3 typical organic fluids were selected as working fluids for a sample slag washing water binary power plants. In this system, the working fluids obtain the thermal energy from slag washing water sources. Thus, it plays a significant role on the cycle performance to select the suitable working fluid. Energy and exergy efficiencies of 3 typical organic fluids were calculated. Dry type fluids (i.e., R227ea) showed higher energy and exergy efficiencies. Conversely, wet fluids (i.e., R143a and R290) indicated lower energy and exergy efficiencies, respectively.
Źródło:
Archives of Thermodynamics; 2017, 38, 3; 49-62
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The literature review of Supply Chain performance measurement in the manufacturing industry
Autorzy:
Sillanpää, I.
Kess, P.
Powiązania:
https://bibliotekanauki.pl/articles/407345.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
przemysł przetwórczy
łańcuch dostaw
wydajność
zarządzanie
supply chain
performance measurement
supply chain management
manufacturing industry
strategy
operations
Opis:
The article addresses the issues of Supply Chain (SC) performance measurement - the process of qualifying the efficiency and effectiveness of the supply chain. The aim of this study is to present a supply chain measurement approaches for manufacturing industry. The research is based on a review of the current understanding of supply chain management and literature related to supply chain performance measurement. This study creates a framework for supply chain measurement by presenting the main theory framework of supply chain performance measurement. It is stated that supply chain performance measurement is extremely important in developing supply chain. The measurement framework in this study offers guidelines for measuring the supply chain in manufacturing industry.
Źródło:
Management and Production Engineering Review; 2012, 3, 2; 79-88
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resource-saving technologies of railway transportation of grain freights for export
Autorzy:
Kozachenko, D.
Vernigora, R.
Kuznetsov, V.
Lahvinova, N.
Rustamov, R.
Papahov, A.
Powiązania:
https://bibliotekanauki.pl/articles/223476.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
rail transportation
grain export
efficiency
consignor routing
concentration of loading
cluster analysis
transport kolejowy
eksport zboża
wydajność
Opis:
The research objective is to increase the efficiency of export railway transportation of grain freights in Ukraine by the introduction of consignor routing, a concentration of loading of grain on junction elevators and the organization of the movement of grain routes according to the schedule. According to the researchers in USA and EU, one of the effective directions for decreasing the expenses in a logistic chain of grain delivery to ports is consignor routing of railway transportation. Consignor routing of transportations of grain freights provides a concentration of their loading at junctions. The choice of junctions is proposed to be carried out on the basis of methods of the cluster analysis. For formation of regions for a concentration of grain loading the theory of sets and multicriteria optimization are used. As a result, on the basis of the modified simplex method are chosen 24 regions of possible concentration of grain loading that cover 70 stations on Ukrainian railways providing 7,5 million t consignor routing for grain in a year with minimal additional expenses. The assessment of the efficiency of railway transportation routing of grain freights is calculated with use of the developed simulation model. Researches showed that application of consignor routing allows to reduce a turn-round cycle for grain wagon in a logistic chain of deliveries up to 27%, and application of the schedule for consignor routes allows to reduce a turn-round cycle up to 62%, in comparison with transportation by car loading. Thus, as showed the calculations executed for one of the directions of grain transportation for export, the necessary operation park of grain-carrier wagons is reduced twice, thereby allowing to cut logistic expenses on a delivery of the Ukrainian grain through seaports to the world markets.
Źródło:
Archives of Transport; 2018, 45, 1; 63-74
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parallel anisotropic mesh refinement with dynamic load balancing for transonic flow simulations
Autorzy:
Gepner, S.
Majewski, J.
Rokicki, J.
Powiązania:
https://bibliotekanauki.pl/articles/202281.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
parallel CFD
adaptation
dynamic load balancing
mesh refinement
parallel efficiency
CFD
dostosowanie
dynamiczne obciążenia
wydajność
modele siatkowe
Opis:
The present paper discusses an effective adaptive methods suited for use in parallel environment. An in-house, parallel flow solver based on the residual distribution method is used for the solution of flow problems. Simulation is parallelized based on the domain decomposition approach. Adaptive changes to the mesh are achieved by two distinctive techniques. Mesh refinement is performed by dividing element edges and a subsequent application of pre defined splitting templates. Mesh regularization and derefinement is achieved through topology conserving node movement (r-adaptivity). Parallel implementations of an adaptive use the dynamic load balancing technique.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2017, 65, 2; 195-207
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energetic Efficiency of Mixing and Mass Transfer in Single Phase and Two-Phase Systems
Autorzy:
Bałdyga, J.
Jasińska, M.
Powiązania:
https://bibliotekanauki.pl/articles/184853.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chemical test reaction
energetic efficiency
mass transfer
mixing
chemiczne reakcje testowe
wydajność energetyczna
transfer masy
mieszanie
Opis:
In this work a concept of energetic efficiency of mixing is presented and discussed; a classical definition of mixing efficiency is modified to include effects of the Schmidt number and the Reynolds number. Generalization to turbulent flows is presented as well. It is shown how the energetic efficiency of mixing as well as efficiencies of drop breakage and mass transfer in twophase liquid-liquid systems can be identified using mathematical models and test chemical reactions. New expressions for analyzing efficiency problem are applied to identify the energetic efficiency of mixing in a stirred tank, a rotor stator mixer and a microreactor. Published experimental data and new results obtained using new systems of test reactions are applied. It has been shown that the efficiency of mixing is small in popular types of reactors and mixers and thus there is some space for improvement.
Źródło:
Chemical and Process Engineering; 2017, 38, 1; 79-96
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The simultaneous effect of the operating temperature and solar radiation on the efficiency of photovoltaic panels
Jednoczesny wpływ temperatury pracy oraz promieniowania słonecznego na wydajność ogniw fotowoltaicznych
Autorzy:
Heim, D.
Powiązania:
https://bibliotekanauki.pl/articles/231179.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
temperatura pracy
promieniowanie słoneczne
wydajność
ogniwo fotowoltaiczne
symulacja
operating temperature
solar radiation
efficiency
photovoltaic cell
simulation
Opis:
The proper designing of PV systems requires the use of advanced building energy simulation techniques. It allows to design the best position of the PV array, as well as the right quantity of produced energy in different cases. On the other hand the PV efficiency is not only a constant value but changes according to temperature and solar radiation. This paper is devoted to estimate the simultaneous effect of both weather factors on PV efficiency. The task was achieved by numerical simulation and ESP-r software. Computer simulations have been carried out with the use of the Typical Meteorological Year data for Warsaw (52°N 21°E). The greatest influence of temperature on the efficiency of solar energy conversion was observed for crystalline silicon cells. The influence of the boundary conditions assumed in the study is ignored for amorphous silicon cells in the summer period and regardless of the material type in the winter period.
Fotowoltaika jest najbardziej popularnym systemem konwersji energii promieniowania słonecznego na prąd elektryczny. Energia elektryczna produkowana przez systemy PV może być spożytkowana na potrzeby danego użytkownika, zaś jej ewentualna nadwyżka sprzedana bezpośrednio do sieci elektroenergetycznej. Prawidłowe zaprojektowanie systemu PV wymaga użycia zaawansowanych technik symulacji energetycznych budynków. Pozwalają one na wybór najlepszego usytuowania oraz dają prawidłową informacje na temat możliwej do uzyskania ilości energii. Z innej jednak strony, systemy PV nie posiadają stałej wydajności a jest ona zależna od temperatury pracy oraz docierającego do ogniwa promieniowania słonecznego. Wpływ temperatury na wydajność ogniw PV jest dobrze znana z literatury przedmiotu. Artykuł ten ma natomiast na celu oszacowanie jednoczesnego wpływu temperatury i promieniowania na wydajność ogniw. Główny cel osiągnięty został poprzez obliczenia symulacyjne z zastosowaniem zaawansowanego narzędzia obliczeniowego, programu ESP-r. Obliczenia przeprowadzono dla danych meteorologicznych Warszawy. Uwzględniono zarówno promieniowanie bezpośrednie jak i rozproszone. Wyznaczono ilość wyprodukowanej energii dla wybranych tygodni oraz wpływ temperatury i promieniowania słonecznego na wydajność ogniw PV. Największy wpływ temperatury na wydajność konwersji energii słonecznej zaobserwowano latem dla ogniw wykonanych z krzemu krystalicznego. Dla ogniw wykonanych z krzemu amorficznego w okresie lata oraz bez względu na rodzaj materiału w okresie zimy wpływ temperatury dla przyjętych warunków obliczeniowych był pomijany. Istotny natomiast był wpływ zmieniającego się natężenia promieniowania, którego spadek znacznie obniża zdolność konwersji fotoelektrycznej zarówno w okresie zimy jak i lata.
Źródło:
Archives of Civil Engineering; 2011, 57, 3; 261-274
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment
Nowy sposób ekstrakcji pierwiastków ziem rzadkich z proszków NdFeB w roztworach alkalicznych
Autorzy:
Chung, K. W.
Kim, C.-J.
Yoon, H.-S.
Powiązania:
https://bibliotekanauki.pl/articles/355324.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
recycling
NdFeB magnet
alkaline treatment
leaching
selective leaching efficiency
recykling
magnes neodymowy
obróbka alkaliczna
ługowanie
wydajność
Opis:
The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100°C was performed. The resultant powders were then leached in 0.5M H2SO4 solution at 25°C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1301-1305
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluating the impact of long cargo dwell time on port performance: an evaluation model of Douala International Terminal in Cameroon
Autorzy:
Aminatou, M.
Jaqi, Y.
Okyere, S.
Powiązania:
https://bibliotekanauki.pl/articles/223976.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cargo
dwell time
quay
port
port performance
terminal operations
ładunek
czas oczekiwania
nadbrzeże
wydajność portu
terminal
Opis:
Create as part of the concession agreement signed by the Container Terminal 28 June 2004 with the port of Douala international terminal (DIT) Company aims to manage, operate and develop the Port’s container handling activity in Douala. This paper investigates the main factors explaining long container dwell times in Douala Port. Using original and extensive data on container imports in the Port of Douala, it seeks to provide a basic understanding of why containers stay on average more than two weeks in port space while long dwell times are widely recognized as a critical hindrance to economic development. It also demonstrates the interrelationships that exist between logistics performance of consignees, operational performance of port operators and efficiency of customs clearance operations. Shipment level analysis is used to identify the main determinants of long cargo dwell times and the impact of shipment characteristics such as fiscal regime, density of value, bulking and packaging type, last port of call, and region of origin or commodity group on cargo dwell time in ports is tested. External factors, such as performance of clearing and forwarding agents, shippers and shipping line strategies, also play an important role in the determination of long dwell times.
Źródło:
Archives of Transport; 2018, 46, 2; 7-20
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of waste heat energy sources of a conventional steam propulsion plant of an LNG carrier
Autorzy:
Adamkiewicz, Andrzej
Grzesiak, Szymon
Powiązania:
https://bibliotekanauki.pl/articles/240754.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
waste heat energy
steam turbine
efficiency
propulsion plant
energia cieplna odpadowa
silnik parowy
wydajność
instalacja napędowa
Opis:
This paper presents the origins of marine steam turbine application on liquefied natural gas carriers. An analysis of alternative propulsion plant trends has been made. The more efficient ones with marine diesel engines gradually began to replace the less efficient plants. However, because of many advantages of the steam turbine, further development research is in progress in order to achieve comparable thermal efficiency. Research has been carried out in order to achieve higher thermal efficiency throughout increasing operational parameters of superheated steam before the turbine unit; improving its efficiency to bring it nearer to the ideal Carnot cycle by applying a reheating system of steam and multi stage regenerative boiler feed water heating. Furthermore, heat losses of the system are reduced by: improving the design of turbine blades, application of turbine casing and bearing cooling, as well as reduction in steam flow resistance in pipe work and maneuvering valves. The article identifies waste energy sources using the energy balance of a steam turbine propulsion plant applied on the liquefied natural gas carrier which was made out basing on results of a passive operation experiment, using the measured and calculated values from behavioral equations for the zero-dimensional model. Thermodynamic functions of state of waste heat fluxes have been identified in terms of their capability to be converted into usable energy fluxes. Thus, new ways of increasing the efficiency of energy conversion of a steam turbine propulsion plant have been addressed.
Źródło:
Archives of Thermodynamics; 2019, 40, 3; 195-210
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies