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Tytuł:
The propinquity of divisors
Autorzy:
Hall, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/1392481.pdf
Data publikacji:
1987
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Źródło:
Acta Arithmetica; 1987-1988, 49, 2; 155-163
0065-1036
Pojawia się w:
Acta Arithmetica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integration of ship hull assembly sequence planning, scheduling and budgeting
Autorzy:
Iwańkowicz, R R
Powiązania:
https://bibliotekanauki.pl/articles/101940.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
assembly sequence planning
schedulling
shipbuilding
budgeting
resource consumption
ship hull
Opis:
The specificity of the yard work requires the particularly careful treatment of the issues of scheduling and budgeting in the production planning processes. The article presents the method of analysis of the assembly sequence taking into account the duration of individual activities and the demand for resources. A method of the critical path and resource budgeting were used. Modelling of the assembly was performed using the acyclic graphs. It has been shown that the assembly sequences can have very different feasible budget regions. The proposed model is applied to the assembly processes of large-scale welded structures, including the hulls of ships. The presented computational examples have a simulation character. They show the usefulness of the model and the possibility to use it in a variety of analyses.
Źródło:
Advances in Science and Technology. Research Journal; 2015, 9, 25; 12-19
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave propagation in micropolar monoclinic thermoelastic half space
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/955283.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
termoelastyczność
naprężenia
fala harmoniczna
Opis:
Propagation of waves in a micropolar monoclinic medium possessing hermoelastic properties based on the Lord- Shulman (L-S),Green and Lindsay (G-L) and Coupled thermoelasticty (C-T) theories is discussed. The investigation is divided into two sections, viz., plane strain and anti-plane strain problem. After developing the solution, the phase velocities and attenuation quality factor have been derived and computed numerically. The numerical results have been plotted graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 4; 1013-1023
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of axi-symmetric vibrations in a micropolar transversely isotropic layer
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/947327.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fala symetryczna
anizotropia
fala akustyczna
micropolar
transversely isotropic
amplitude ratios
Opis:
The present investigation deals with the propagation of circular crested Lamb waves in a homogeneous micropolar transversely isotropic medium. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitudes of displacements and microrotation are computed numerically for magnesium as a material and the dispersion curves, amplitudes of displacements and microrotation for symmetric and skew-symmetric wave modes are presented graphically to evince the effect of anisotropy. Some special cases of interest are also deduced.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 2; 259-268
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of waves generated in transversely isotropic micropolar generalized thermoelastic half space under temperature dependent properties
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/264335.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
propagacja fal
termoelastyczność
naprężenia
micropolar
transversely isotropic
generalized thermoelastic
amplitude ratios
Opis:
The present study deals with the propagation of waves in a transversely isotropic micropolar generalized thermoelastic material possessing temperature dependent elastic properties. After developing the solution for LS, GL and CT theory, the phase velocities and attenuation quality factor have been obtained. The expressions for amplitudes of stresses, displacements, microratation and temperature distribution have been derived and computed numerically. The numerically evaluated results have been plotted graphically. Some particular cases of interest have also been obtained.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 4; 53-65
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflection of waves in initially stressed transversely isotropic fibre-reinforced thermoelastic medium
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/264883.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
odbicie
termoelastyczność
odbicie fali
reflection
initially stressed
fiber-reinforced
transversely isotropic
Opis:
The present investigation deals with the reflection of plane periodic waves incident at the surface of a homogeneous initially stressed transversely isotropic fibrereinforced thermoelastic medium. The wave equations are solved by imposing proper conditions on displacements, stresses and temperature distribution. Numerically simulated results have been depicted graphically for different angles of incidence with respect to frequency. Some special cases of interest have also been deduced from the present investigation.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 3; 671-685
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of waves in the layer of a thermo-viscoelastic transversely isotropic medium
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/265026.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
lepkosprężystość
termosprężystość
prędkość fazowa
viscoelastic
thermoelasticity
phase velocity transversely isotropic
Opis:
The article is presented to enhance our knowledge about the propagation of Lamb waves in the layer of a viscoelastic transversely isotropic medium in the context of thermoelasticity with GN theory of type-II and III. Secular equations for symmetric and skew-symmetric modes of wave propagation in completely separate terms are derived. The amplitudes of displacements and temperature distribution were also obtained. Finally, the numerical solution was carried out for cobalt and the dispersion curves, amplitudes of displacements and temperature distribution for symmetric and skew-symmetric wave modes are presented to evince the effect of anisotropy. Some particular cases are also deduced.
Źródło:
International Journal of Applied Mechanics and Engineering; 2016, 21, 1; 21-35
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wave propagation in a micropolar transversely isotropic generalized thermoelastic half-space
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/955189.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
termosprężystość
prędkość fazowa
współczynnik tłumienia drgań sprężystych
micropolar
transversely isotropic
generalized thermoelastic
amplitude ratios
Opis:
Rayleigh waves in a half-space exhibiting microplar transversely isotropic generalized thermoelastic properties based on the Lord-Shulman (L-S), Green and Lindsay (G-L) and Coupled thermoelasticty (C-T) theories are discussed. The phase velocity and attenuation coefficient in the previous three different theories have been obtained. A comparison is carried out of the phase velocity, attenuation coefficient and specific loss as calculated from the different theories of generalized thermoelasticity along with the comparison of anisotropy. The amplitudes of displacements, microrotation, stresses and temperature distribution were also obtained. The results obtained and the conclusions drawn are discussed numerically and illustrated graphically. Relevant results of previous investigations are deduced as special cases.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 2; 247-257
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface wave characteristics in a micropolar transversely isotropic halfspace underlying an inviscid liquid layer
Autorzy:
Gupta, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/955310.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fala Rayleigha
propagacji fal
liczba falowa
micropolar
transversely isotropic
amplitude ratios
Rayleigh waves
Opis:
The present investigation deals with the propagation of waves in a micropolar transversely isotropic half space with an overlying inviscid fluid layer. Effects of fluid loading and anisotropy on the phase velocity, attenuation coefficient, specific loss and relative frequency shift. Finally, a numerical solution was carried out for aluminium epoxy material and the computer simulated results for the phase velocity, attenuation coefficient, specific loss and relative frequency shift are presented graphically. A particular case for the propagation of Rayleigh waves in a micropolar transversely isotropic half-space is deduced and dispersion curves are plotted for the same as functions of the wave number. An amplitude of displacements and microrotation together with the path of surface particles are also calculated for the propagation of Rayleigh waves in the latter case.
Źródło:
International Journal of Applied Mechanics and Engineering; 2014, 19, 1; 49-60
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Blended learning approach in improving student’s academic performance in information communication, and technology (ICT)
Autorzy:
Germo, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/2172496.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
maritime education and training
communication and technology
blended learning
bachelor of science in marine transportation
system in Philippines
traditional method of teaching
Mann-Whitney test
wilcoxon-signed ranks
Opis:
This quasi-experimental study aimed at looking into the effectiveness of blended learning approach in improving the performance in Information, Communication, and Technology (ICT) Course of Bachelor of Science in Marine Transportation (BSMT) first year students at JBLFMU-Arevalo during the second semester of school year 2018-2019. The respondents of this research were the two sections comparable with each other who were enrolled in the subject ICT. There were 40 student respondents composed of 20 in the experimental group and 20 in the control group. A validated and reliability-tested 45 item researcher-made multiple choice test was used as an instrument with a Cronbach index of 0.88. The statistical tools used were mean, standard deviation, Mann-Whitney test, and Wilcoxon-Signed ranks test set at .05 level of significance. The effect size was computed to determine the effectiveness of the blended learning approach in terms of students’ performance in ICT. Results showed that in the pretest, though the experimental group had a higher mean score than the control group, the Mann-Whitney test showed that the mean scores of the two groups were comparable because the significant value was greater than .05. When the treatment was introduced, findings showed that there were significant differences in the ICT performance in the pretest and posttest of experimental and control groups as well as in the posttests of both groups. Results inferred that blended learning approach was more than a hundred percent effective showing significant results on the experimental group. It could also be inferred that the better performance of the control group could be attributed to the traditional method of teaching, the lecture method.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2022, 16, 2; 251--256
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards optimal design of energy efficient buildings
W kierunku projektowania budynków efektywnych energetycznie
Autorzy:
Gajewski, R. R.
Kułakowski, T.
Powiązania:
https://bibliotekanauki.pl/articles/231240.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
budynek efektywny energetycznie
symulacja
weryfikacja
walidacja
MES
MRS
energy efficient building
simulation
verification
validation
FEM
FVM
FDM
Opis:
Buildings consume half of all energy use and are also responsible for a similar proportion of carbon dioxide emission. The heat transfer across the building envelope - the shell of a house that separates the inside and outside - should generally be minimized. In the paper validation and verification based on Building Energy Simulation Test (BESTEST) of Energy3D computer code is presented. Next, computations performed by means of Energy 3D and Energy Plus for BESTEST building are compared. In the last part of the paper results for computations for real building are presented. Program Energy 3D proved to be an excellent tool for qualitative and quantitative analysis of buildings with respect to energy consumption.
W związku ze znaczącym udziałem budynków w globalnym zapotrzebowaniu na energię ich projektowanie staje się coraz bardziej ukierunkowane na efektywne wykorzystanie nieodnawialnych zasobów takich jak np. paliwa kopalne. Celem niniejszej publikacji jest prezentacja możliwości jakie daje wykorzystanie oprogramowania do symulacji energetycznych budynków przy ich projektowaniu. We współpracy z firmą Wienerberger, która udostępniła dane dotyczące ich budynku modelowego oraz wyniki symulacji przeprowadzonych przez Narodową Agencję Poszanowania Energii S.A. w ramach optymalizacji jego projektu, autorzy porównali możliwości przykładowych, dostępnych komercyjnie narzędzi symulacyjnych – Energy3D oraz EnergyPlus (Design Builder) oraz porównali z wynikami benchmarkowymi na przykładzie budynku BESTEST. Poza omówieniem założeń obliczeniowych, a także dostępnych funkcjonalności programów, niniejszy artykuł zawiera streszczenie zagadnień wymagających rozwiązania przy symulacjach dynamicznej wymiany ciepła w budynkach oraz wybrane metody obliczeniowe stosowane w komercyjnych programach komputerowych.
Źródło:
Archives of Civil Engineering; 2018, 64, 4/II; 135-153
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance Evaluation of the TFD-capable Dynamic QoS Assurance of HD Video Streaming in Well-dimensioned Network
Autorzy:
Chodorek, A.
Chodorek, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/226473.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
quality of service assurance
performance evaluation
HD video streaming
heterogeneous IP network
traffic flow description option
Opis:
The Traffic Flow Description (TFD) option of the IP protocol is an experimental option, designed by the Authors and described by the IETF’s Internet Draft. This option was intended for signalling for QoS purposes. Knowledge about forthcoming traffic (such as the amount of data that will be transferred in a given period of time) is conveyed in the fields of the option between end-systems. TFD-capable routers on a path (or a multicast tree) between the sender and receiver(s) are able to read this information, process it and use it for bandwidth allocation. If the time horizons are short enough, bandwidth allocation will be performed dynamically. In the paper a performance evaluation of an HD video transmission QoS assured with the use of the TFD option is presented. The analysis was made for a variable number of video streams and a variable number of TCP flows that compete with the videos for the bandwidth of the shared link. Results show that the dynamic bandwidth allocation using the TFD option better assures the QoS of HD video than the classic solution, based on the RSVP protocol.
Źródło:
International Journal of Electronics and Telecommunications; 2018, 64, 3; 357-364
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solving the problem of vehicle routing by evolutionary algorithm
Autorzy:
Iwańkowicz, R. R.
Sekulski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/102797.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
vehicle routing
travelling salesman
genetic algorithm
Opis:
In the presented work the vehicle routing problem is formulated, which concerns planning the collection of wastes by one garbage truck from a certain number of collection points. The garbage truck begins its route in the base point, collects the load in subsequent collection points, then drives the wastes to the disposal site (landfill or sorting plant) and returns to the another visited collection points. The filled garbage truck each time goes to the disposal site. It returns to the base after driving wastes from all collection points. Optimization model is based on genetic algorithm where individual is the whole garbage collection plan. Permutation is proposed as the code of the individual.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 29; 97-108
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Xylem-fed maple sap accelerates balsam fir needle abscission and but can delay water loss in spring and autumn
Autorzy:
MacDonald, M.T.
Lada, R.R.
West, R.R.
Nelson, K.L.
Powiązania:
https://bibliotekanauki.pl/articles/40990.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
xylem
abscisic acid
Abies balsamea
balsam
fir tree
balsam fir tree
needle
water content
water uptake
water loss
spring
autumn
Opis:
Postharvest balsam fir trees are known to suffer a number of problems that may be linked to abscission rates, such as dehydration or wounding. By definition, postharvest balsam fir trees are also detached from roots and will no longer be supplied certain root derived factors normally translocated via the xylem. Resupplying those root derived factors may delay abscission. The objective of this experiment was to take sap from a root intact species (i.e. Acer saccharum L) and add it to the water supply of balsam fir branches. Further, the effect of reverse osmosis and autoclaving the sap supply will be explored. The experiment was conducted once in spring and again in autumn to examine seasonal changes in needle abscission. The only hormones found in the maple sap were ABA and its metabolites, with PA (163.0 ng g–1) being the primary metabolite present. Needle retention was higher in branches harvested in autumn, as long as they were provided a sap that did not undergo RO. If the sap had undergone RO, then needle retention was slightly decreased in autumn. Needle retention generally decreased as the concentration of maple sap in the water supply increased and this trend was accelerated if the sap had undergone RO. Autoclaving the sap successfully delayed the length of time for water consumption to decrease, but this unexpectedly did not translate into improved needle retention.
Źródło:
Dendrobiology; 2016, 76
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature and Intensity Dependent Faraday Rotation in Hg$\text{}_{1-x}$Mn$\text{}_{x}$Te at CO$\text{}_{2}$ Laser Wavelengths
Autorzy:
Kowałczyk, L.
Gałązka, R. R.
Powiązania:
https://bibliotekanauki.pl/articles/1891287.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ls
75.30.El
Opis:
Faraday rotation in Hg$\text{}_{1-x}$Mn$\text{}_{x}$Te (x = 0.11) has been investigated experimentally over the temperature range from T = 8 K to 250 K using a Q-switched CO$\text{}_{2}$ laser. Due to the exchange interaction between mobile carriers and localized Mn ions, dramatic enhancement of Verdet coefficient at low temperatures has been observed. The values of Verdet coefficient V = 5585 rad T$\text{}^{-1}$ m$\text{}^{-1}$ at 8 K and V = 1745 rad T$\text{}^{-1}$ m$\text{}^{-1}$ at 80 K have been obtained for Hg$\text{}_{0.89}$Mn$\text{}_{0.11}$Te at 10.6 μm. The dependence of Faraday rotation on intensity of laser radiation has been observed. Intensity dependent Faraday rotation shows saturation for high laser power. Intensity induced rotation is qualitatively attributed to the dispersion associated with saturable absorption of laser radiation. The results obtained in this work indicate that Hg$\text{}_{1-x}$Mn$\text{}_{x}$Te is a suitable material for Faraday rotator at CO$\text{}_{2}$ laser wavelengths for high power laser beam.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 429-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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