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Wyszukujesz frazę "L. J." wg kryterium: Wszystkie pola


Tytuł:
P-38 J-L Lightning
Autorzy:
Pęczkowski, Robert.
Współwytwórcy:
Juszczak, Artur. Ilustracje
Matusiak, Wojciech. Tłumaczenie
Data publikacji:
2003
Wydawca:
Sandomierz : "Stratus"
Tematy:
Lockheed P-38 Lightning (samolot) Stany Zjednoczone 1939-1945 r. wydawnictwa popularne
Samoloty myśliwskie Stany Zjednoczone 1939-1945 r. wydawnictwa popularne
Fighters
Opis:
Tyt. okł.: Lookheed P-38 J-L Lightning. --- Tekst tł. z pol.
Bibliogr. s. 111.
Dostawca treści:
Bibliografia CBW
Książka
Tytuł:
Optical Processes in Quantum Wells
Autorzy:
Sham, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/1931845.pdf
Data publikacji:
1995-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
78.55.Cr
Opis:
A review is given of the theoretical framework of exciton dynamics in quantum wells including the spin degrees of freedom. A study is made of various momentum, energy, and spin relaxation mechanisms including the effects of exciton-phonon interaction, the single-particle spin-flips by means of spin-orbit interaction and the exciton spin-flip by means of the exchange interaction. All these competing mechanisms are taken into account in a set of equations governing the time evolution of the exciton spin populations. Solutions are then used to interpret observed time-resolved observations of polarized luminescence spectra. For excitons in a two-dimensional system such as a semiconductor quantum well, the breaking of the translational symmetry in the direction normal to the interface plane has been shown theoretically by Hanamura, by Andreani and Bassani, and by Citrin to result in a recombination rate much faster than in a three-dimensional system. Yet, experiments show comparable decay rates in two- and three-dimensional excitons. Recent experiments with high time resolutions show two decay times for the total luminescence intensity. The slower one agrees with the one usually observed and interpreted as the radiative recombination time. We shall give an explanation for the fast decay as a combination of radiative recombination and single-particle spin-flip and for the slow decay as the radiative recombination slowed down by the presence of lower energy dark states for excitons with parallel spins. The ability to use the same theory to account for the polarization behavior confirms the importance of the exciton spin dynamics. Furthermore, the longitudinal electric field dependence is used to check our theory of exchange.
Źródło:
Acta Physica Polonica A; 1995, 87, 1; 7-15
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some aspect of theory of cumulated fuel consumption
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/247685.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
vehicle
engine
fuel consumption
Opis:
A theory of cumulated fuel consumption in process ofvehicle operation is described. The method of creation the mathematical model and procedure of determination of model variables is shown. The mainfeatures of cumulated fuel consumption are painted attention. li is shown that the theory of cumulated fuel consumption can be use to description of the fuel consumption from beginning the exploitation of vehicles and also for the situation when the vehicle are in exploitation from any time and further fuel consumption are unknown. An example of utilisation of elaborated theory for assessment of operation of passenger car is also presented. It has been shown that applying the theory of cumulated fuel consumption, the course of such consumption can be accurately described also in this case. This proposal can be formulated in spite of making some simplifications. This is because the unknown value of the accumulated fuel before start the time of observation operation will be determined using the average (from the average) fuel consumption. This simplification greatly facilitates the flow of the calculations and it seems does not offend errors in the calculations. Method of determining the average is discussed in the article. It appears that such treatment may be justified by the fact that the mistake is, in principle, systematic error. Very high coefficients of mathematical model to fit the measured data are very interesting. Such regularity was observed during researches in buses transport [l], intercity buses, and the fleets of various vehicles (the results of researches are not yet published).The introduction of the theory of cumulated fuel consumption as one of the important parameters to assess the operation of the vehicle or vehicles may also be useful in exploitation researches. At present times the researches in which the vehicles are already in service and the engine control mops are tuned (chip tuning), are made. A good performance of these changes is often observed on chassis dyno but that is not properly sanctioned in natural exploitation. Experimentation with such issue is underway and will be the subject of future analysis (and publications).
Źródło:
Journal of KONES; 2010, 17, 4; 447-453
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of cumulative fuel consumption by LPG powered cars
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/243674.pdf
Data publikacji:
2015
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
fuel consumption
theory
applications
Opis:
Theory of cumulative fuel consumption is shown for the first time in [1] and [2]. The theory of cumulative fuel consumption has been presented also in this work. The example of LPG car research results have shown the way of getting to mathematical model of cumulative fuel consumption and the intensity of cumulative fuel consumption. In this case, the studies were carried out 16 cars whose engines were powered by LPG. The vehicles are operated in a small fleet of vehicles, which run in city traffic. Data on outcomes of exploitation and operation fuel consumption is acquired from the accounting documents of the company. Very good results prediction mathematical model of operational data are obtained. The high value of prescience quotients (in this case R-sq > 9.999) are similar to the values that were obtained in various other cases. Conversance of mathematical model of cumulative fuel consumption allows carrying out comprehensive analysis of this significant exploitative parameter. The presented theory must not only be regarded as a theory of cumulative fuel consumption but also can be seen more broadly as a theory of cumulative energy consumption. Research is being conducted on the application of the theory to evaluate energy consumption by hybrid vehicles. The results can be very interesting.
Źródło:
Journal of KONES; 2015, 22, 4; 275-280
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remarks on Statistical Design Centering
Autorzy:
Opalski, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/226467.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
statistical design centering
design yield
realistic worst-case design
stochastic approximation
propagation of variance
Monte Carlo simulation
Opis:
The paper overviews optimization based statistical design centering techniques for analog circuits. Emphasis is placed on dependence between formulation of quality indices, problem formulation, and computational complexity of design centering algorithms, executed in single- or multiple-processor environments. For characterization of solution techniques a standard CMOS op-amp design case and a simplified computational complexity analysis are used.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 2; 159-167
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistic of fuel consumption in test and in natural operation of vehicles
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/133771.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
operation of vehicles
test
fuel consumptions
eksploatacja pojazdów
zużycie paliwa
Opis:
The lowering of carbon dioxide emission is world pursuit which is written in international agreement. It concerns all economy sections, especially motorization. In this last case the lowering is essential, since almost all fuel used for powering vehicles comes from nonrenewable resources. Using these fuels means a one-way carbon motion from underground lode to earth atmosphere. This process has to be immediately stopped. For several years there have been taken actions in this direction. There are both legislative and technical actions. However, the reports which were published in 2016 shows that despite the efforts and engagement of considerable means, the effects are mediocre. There has been noticed, that, though the lowering of carbon dioxide emission determined in bench tests has been attained, it is impossible to notice this progress in natural operation of vehicles. The causes of such a state are sought mainly in incompatibility of test conditions to the real operation of vehicles conditions. Assuming that the carbon dioxide emission is (quasi) directly proportional to fuel consumption, in the article there has been proposed the method of solving the problem of removing divergence between test and operational data. There has been suggested the different attitude to bench data analysis and implementation of new calculative procedures in a way to reach the correlation between the test and operating fuel consumption.
Źródło:
Combustion Engines; 2017, 56, 4; 239-244
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boiling heat transfer phenomenon from an isolated nucleation center
Wymiana ciepła przy wrzeniu dla wyodrębionego centrum nukleacji
Autorzy:
Orman, Ł. J.
Powiązania:
https://bibliotekanauki.pl/articles/402086.pdf
Data publikacji:
2016
Wydawca:
Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
Tematy:
boiling heat transfer
nucleation center
wymiana ciepła przy wrzeniu
centrum nukleacji
Opis:
The paper discusses a method of boiling heat transfer investigation from a cavity of given geometrical dimensions. The testing method is described together with literature review on the subject. This experimental concept can be used to provide useful data on the creation and departure frequency of bubbles, thus giving more insight into the boiling phenomenon.
Źródło:
Structure and Environment; 2016, 8, 1; 59-63
2081-1500
Pojawia się w:
Structure and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transestrification of biofuel, yes but why?
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/242003.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
diesel engines
fuels
alternative fuels
biofuel
Opis:
This paper presents a novel way of utilizing alcohols as fuels for a diesel engine. It is proposed to use heavy alcohols as a mix with vegetable oils and conventional diesel fuel. It is presented the another way to use alcohols. Namely, the use of heavy alcohols as a solvent for vegetable oil (named the biomix or BM) and after the obtainment of the thickness, which would be approximate to diesel fuel, mixing the biomix with diesel fuel to obtained biomix diesel (BMD). This solution will be shown for example with butanol as heavy alcohol, rape oil as vegetable oil and conventional diesel fuel. The investigations are carried out with a simple diesel engine on the engine test bed. Main parameters of engine (power output, torque, specifically fuel consumption) and the main exhaust gas component (in this case CO, NOx, PM) will be investigated. There were better results achieved than one expected. Opposed to existing experiences, the maximum of power output and the torque of engine are higher in the whole range of the rotatory speed of the engine crankshaft when the engine biomix diesel (BMD) is reinforced. The addition of the component biomix to fuel influences the specific fuel consumption. Generally with the larger part of the component biomix the specific fuel consumption grows. Because the power of engine also grows up one should expect that in exploitation the specific fuel consumption should not increase. Transestrification process in the proposed solution does not appear. This has large economic meaning. The investment amount (the transestrification plant) is not necessary. The power consumption to get fuel is lower. Vegetable oils are fully used (glycerine is not produced). BMD has stable parameters. The usage of existing infrastructure to this transportation is enough. Very important is that this fuel could be used to reinforce old, existing now and the future diesel engines. The production of butanol is known. It will be interesting to use for the production an electrolysis process, especially in the proposed new plant where the electrolysis process is connected with the process to get the electrical energy from byproducts of electrolysis (i.e. hydrogen and oxygen) in the fuel cell. It seems to be more efficient. The possibility to get butanol from ethanol gives a very good perspective for the use of ethanol from today's overproduction and moreover without the essential change of infrastructure.
Źródło:
Journal of KONES; 2008, 15, 4; 537-544
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New European biofuels for diesel engines
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/243532.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
combustion engines
alternative fuels
biofuels
butanol
Opis:
The World is strongly dependent on crude oil for its transport needs. In order to diminish this dependence, we need to introduce clean, CO2-efficient, secure and affordable transportation fuels. The development of innovative biofuel technologies will help to cover significantly (up to 25% in Europe) road transport fuel needs. Biofuels production of 33 billion litres in 2004 is small compared to 1200 billion litres of gasoline produced annually worldwide. The current production of liquid biofuels in the EU 25 is about 2 Mtoe, which is less than 1% of the market. Recent assessments have concluded that the 2010 targets, 18 Mtoe used in the transport sector, are unlikely to be achieved. There can be three basic possibilities of accomplishing this target: i) use of alcohols (first of all ethanol) and their mixing with petrol; ii) use of fatty acids esters (methyl or ethyl) of vegetable oils and their mixing with diesel fuel, iii) use of synthetic hydrocarbons of the synthetic gas coming from biomass resources and eventually their mixing with other ,,classical" hydrocarbons. This paper presents a novel way of utilizing alcohols as fuels for a diesel engine. It is proposed to use heavy alcohols as a mix with conventional diesel fuel. The possibility to use a mix of butanol (as heavy alcohol) with conventional diesel fuel is demonstrated. Butanol has some key advantages over ethanol and light hydrocarbons (petrol), including higher energy content and better transport characteristics. Moreover, butanol is hydrophobic, so a new logistic infrastructure is not necessary. This paper demonstrates that a diesel-butanol fuel mixture is supplied to a diesel engine without any problems. A consumption of proposed biofuel mixture from +35% to -35% of typical diesel fuel depends on many factors not only on fuel energy density. A near-term effort of BP Biofuels and DuPont to develop and commercialize biobutanol is well-known. Here, it is proposed a new technological process combining electricity generation in fuel cells with electrolysis and a production of butanol from ethanol, which gives an opportunity to reduce today,'s over production of ethanol without a necessary change of existing infrastructure.
Źródło:
Journal of KONES; 2008, 15, 3; 487-491
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cumulated LPG consumption suplied of cars enginees
Skumulowane zużycie LPG zasilającego silniki samochodów
Autorzy:
Sitnik, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/245376.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
eksploatacja
pojazd
paliwo LPG
zużycie
exploitation
vehicle
fuel
LPG
intake
Opis:
Fuel consumption is one of the base variables to take into account in car's exploitation. Important are current and future fuel consumption. Fundamental ąuestion is how time of car 's exploitation is economically grounded. In case of exploitation of the cars' fleet not fewer important is fleet's cost forecasting which, infirst step originated from fuel 's cost. When theory of the cumulate fuel 's consumption was appeared in 2004 [1] forecasting for this matter is possible. Suitability of theory was presented [1] in reference to city bus communication fueled with diesel, in presented result [2] they proved suitable of theory to trunk bus communication (fueled with diesel too) whilst this paper presents results for fleet fueled with LPG. In text presents the mathematics models of cumulated fuel consumption in process of vehicle's exploitation. Presented way and procedure are to construction of solid model. Heeded mention to characteristic qualities of cumulate fuel's consumption. Presented examples of taking advantage of a theory for mark an exploitation of vehicles' fleet fueled with LPG. Further presented forecasting of LPG consumption are for estimate mileage for few vehicles 'fleet and whole fleet. Reported a full prove of a theory of the cumulate fuel's consumption also for LPG.
Zużycie paliwa jest jednym z podstawowych czynników branych pod uwagę w eksploatacji pojazdów. Ważne jest zarówno zużycie aktualnie występujące w eksploatacji jak i prognozowane w dłuższej perspektywie czasowej. Istotne jest bowiem pytanie jak długo eksploatowany powinien być pojazd by miało to uzasadnienie ekonomiczne. W przypadku eksploatacji floty pojazdów nie mniej ważne jest również prognozowanie kosztów eksploatacji floty, a te wynikają w pierwszym rzędzie z kosztów zakupu paliwa. Prognozowanie w omawianej problematyce stało się możliwe po opracowaniu w 2004 roku [1] teorii skumulowanego zużycia paliwa. Przydatność teorii wykazano w odniesieniu do autobusów komunikacji miejskiej zasilanych olejem napędowym, w [2] przedstawiono wyniki potwierdzające przydatność teorii w autobusach komunikacji międzymiastowej, (których silniki były także zasilane olejem napędowym) natomiast w publikacji niniejszej wyniki odnoszące się floty pojazdów zasilanych LPG. W referacie przedstawiono modele matematyczne skumulowanego zużycia paliwa w procesie eksploatacji pojazdu. Podano sposób oraz procedurę wyznaczania stałych modeli. Zwrócono uwagę na charakterystyczne cechy skumulowanego zużycia paliwa. Przedstawiono przykłady wykorzystania opracowanej teorii do oceny eksploatacji floty pojazdów zasilanych LPG. Podano również prognozy zużycia LPG, do zakładanych przebiegów, przez poszczególne pojazdy floty oraz całej floty. Wykazano pełną przydatność opracowanej teorii skumulowanego zużycia paliwa również w wypadku gdy paliwem jest LPG.
Źródło:
Journal of KONES; 2009, 16, 4; 429-434
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł

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