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    Wyświetlanie 1-22 z 22
    Tytuł:
    Electron-ion Recombination at Sub-zero Temperature
    Autorzy:
    Bhattacharyya, S.
    Roy, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2008325.pdf
    Data publikacji:
    1999-06
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    32.70.Fw
    34.80.Kw
    Opis:
    In this paper we have considered two-step radiative recombination channel over the existing spontaneous radiative recombination channel to explain the causes of experimentally obtained enhanced recombination rate at sub-zero temperature. The existing recombination rate due to spontaneous radiative recombination is 4 times smaller than the recent experimental data. In the case of Ne$\text{}^{10+}$ we obtain good agreement between theory and experiment when contribution from two-step radiative recombination channel is added to the spontaneous radiative recombination channel. Recombination rate for Ar$\text{}^{18+}$ is calculated. The radiation spectrum given out by two-step radiative recombination and spontaneous radiative recombination in the recombination rate processes are discrete spectrum and continuous spectrum, respectively. Experimental identification of these two channels through the spectral signatures is suggested.
    Źródło:
    Acta Physica Polonica A; 1999, 95, 6; 911-920
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Three-Particle Recombination at Low Temperature: a QED Approach
    Autorzy:
    Bhattacharyya, S.
    Roy, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/2027431.pdf
    Data publikacji:
    2001-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    32.80.Fb
    33.55.Ad
    Opis:
    A theoretical study of the three-body recombination of proton and electron in presence of a spectator electron with electronic beam at near-zero temperature is presented using field theory and invariant Lorentz gauge. Contributions from the Feynman diagrams of different orders give an insight into the physics of the phenomena. Recombination rate coefficient is obtained for low lying principal quantum number n=1 to 10. At a fixed ion beam temperature (300 K) recombination rate coefficient is found to increase in general with n, having a flat and a sharp peak at quantum states 3 and 5, respectively. In absence of any other theoretical and experimental results for low temperature formation of H-atom by three-body recombination at low lying quantum states, we have presented the theoretical results of Stevefelt and group for three-body recombination of deuteron with electron along with the present results. Three-body recombination of antihydrogen in antiproton-positron plasma is expected to yield similar result as that for three-body recombination of hydrogen formation in proton-electron plasma. The necessity for experimental investigation of low temperature three-body recombination at low quantum states is stressed.
    Źródło:
    Acta Physica Polonica A; 2001, 100, 1; 23-40
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Reactive solute transport in blood flow through a permeable capillary
    Autorzy:
    Debnath, S.
    Roy, A. K.
    Bég, O. A.
    Powiązania:
    https://bibliotekanauki.pl/articles/38695392.pdf
    Data publikacji:
    2022
    Wydawca:
    Instytut Podstawowych Problemów Techniki PAN
    Tematy:
    capillary
    axial flow
    radial flow
    solute dispersion
    Gill decomposition
    filtration coefficient
    exchange coefficient
    advection coefficient
    Opis:
    The present analysis discusses the solute transport process in a steady 2D (axial and radial) laminar flow of blood through a permeable, finite length capillary. Blood is treated as a homogeneous Newtonian fluid and the solute is absorbed at the capillary wall with a linear irreversible reaction rate. The velocity profile is obtained by a regular perturbation technique, whereas the transport coefficients depicted by the Gill generalized dispersion model are solved numerically. A number of different scenarios are considered, namely transport with no-reaction, weak absorption, strong absorption, low filtration or high filtration, etc. In the initial stages, the temporal behaviour of the dispersion coefficient is identical to those cases when there is no radial velocity. For the combined effect of radial and axial velocities, however, the dispersion coefficient is lower for a high absorption rate than for a weak absorption rate. Diffusion is accelerated with higher values of filtration coefficient. Owing to the opposite effects of radial diffusion and radial velocity, the solute particles require more time to reach the steady state. The analysis finds applications in, for example, reactive nutrient and pharmacological transport in capillary hemodynamics.
    Źródło:
    Archives of Mechanics; 2022, 74, 2-3; 173-200
    0373-2029
    Pojawia się w:
    Archives of Mechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Ejaculation malfunctions on the day of oocyte pick up for IVF/ICSI: A report of four cases
    Autorzy:
    Javed, A.
    Ls, A.
    Pathangae, V.G.
    Roy, A.
    Ganguly, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/10946.pdf
    Data publikacji:
    2015
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Opis:
    The procedure of in-vitro fertilization (IVF) is sometime physically stressful and emotional turmoil on the couples undergoing treatment. The male partner is obliged to produce semen for injection/insemination with the oocytes. Unfortunately, some men are ill-fated, not capable to reproduce semen on the day of oocyte pickup.
    Źródło:
    International Letters of Natural Sciences; 2015, 48
    2300-9675
    Pojawia się w:
    International Letters of Natural Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    T-cell proliferation on immunopathogenic mechanism of psoriasis: a control based theoretical approach
    Autorzy:
    Datta, A.
    Roy, P. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/205612.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    T-cells
    dendritic cells
    keratinocytes
    dermis
    epidermis
    cytokines
    T-cell proliferation
    drug efficacy
    optimal control
    Opis:
    Psoriasis vulgaris is a common, worldwide autoimmune skin disorder characterized by T-cells mediated hyperproliferation of keratinocytes. The feature of T-cells arbitrated psoriatic lesions is the epidermal infiltration of oligoclonal CD8+ T-cells and also of CD4+ T-cells in the dermis. Psoriatic scratches are identified by red and enlarged lesions along with silver whitish scales. In this article, we propose a mathematical model for psoriasis, involving a set of differential equations, concerning T-cells, dendritic cells and epidermal keratinocytes. We introduce T-cell proliferation in the system, where T-cells are generated through expansion of accessible CD4+ T-cells from precursors. We are interested in observing how the cell biological system develops through T-cell proliferation in presence of control with respect to T-cells and keratinocytes. We study the model in both implicit and explicit ways and measure the effect of drug on the system through impulsive drug therapy.
    Źródło:
    Control and Cybernetics; 2013, 42, 2; 365-386
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design and Analysis of Single Mode Photonic Crystal Fibers with Zero Dispersion and Ultra Low Loss
    Autorzy:
    Kumar, P.
    Tripathy, A.
    Roy, J. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/963925.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    photonic crystal fibers
    dispersion
    birefringence
    splice loss
    confinement loss
    effective mode area
    Opis:
    PCFs (Photonic Crystal Fibers) with ‘T’ – shaped core have been proposed in this paper. ‘T’ –shaped core PCF structures have been analyzed using two different background materials: silica and lead silicate. A total of 360° rotation at an interval of 90° has been introduced in the design of PCF structures. PCF structures A, B, C and D with rotation of 0°, 90°, 180° and 270° have silica as wafer. Similarly PCF structures E, F, G and H with similar rotation have lead silicate as background material. Numerical investigations shows structures ‘D’, ‘F’, ‘G’ and ‘H’ to have anomalous dispersion. PCF structures ‘F’, ‘G’, and ‘H’ have reported birefringence of the order of 10⁻². Besides, other PCF structures report birefringence of the order of 10⁻³. Ultra low confinement loss has been observed in all the investigated PCF structures. Moreover, splice loss observed by the structure is very low. Large mode area has been shown by all the designed PCF structures.
    Źródło:
    International Journal of Electronics and Telecommunications; 2018, 64, 4; 541-546
    2300-1933
    Pojawia się w:
    International Journal of Electronics and Telecommunications
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Unsteady laminar mixed convection boundary layer flow near a vertical wedge due to oscillations in the free-stream and surface temperature
    Autorzy:
    Roy, N. C.
    Hossain, A.
    Hussain, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/264762.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    konwekcja mieszana
    granica przepływu warstwy
    przepływ ciepła
    mixed convection
    boundary layer flow
    vertical wedge
    free-stream oscillation
    Opis:
    The unsteady laminar boundary layer characteristics of mixed convection flow past a vertical wedge have been investigated numerically. The free-stream velocity and surface temperature are assumed to be oscillating in the magnitude but not in the direction of the oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the straightforward finite difference method for the entire frequency range, and the extended series solution for low frequency range and the asymptotic series expansion method for high frequency range. The results demonstrate the effects of the Richardson number, Ri, introduced to quantify the influence of mixed convection and the Prandtl number, Pr, on the amplitudes and phase angles of the skin friction and heat transfer. In addition, the effects of these parameters are examined in terms of the transient skin friction and heat transfer.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2016, 21, 1; 169-186
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Negative Shrinkage of Thin-walled Investment Brass Castings
    Autorzy:
    Roy, Soumyajit
    Pramanick, A. K.
    Datta, P. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/27314113.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    "Dokra or Dhokra"
    cast craft tradition
    India
    thin-walled castings
    brass castings
    tradycyjna metoda odlewnicza
    Indie
    odlewy cienkościenne
    odlewy mosiężne
    forma odlewnicza
    Opis:
    Dhokra or Dokra casting is a sophisticated cast metal craft tradition of the Indian subcontinent. It has been practiced by the countryfolk now since the Copper Age. It is a lost wax casting process in the hot clay mold. The technology is such sophisticated that it can produce up to 400 μm thin-walled hollow cast products with complicated and intricate shapes using Brass, Bronze, Copper, and other copper alloys. The investigation was for engraving Brass (2% lead) which is used by Dhokra artisans nowadays. In a field visit during dimensional analysis, one discrepancy was identified. The metal thicknesses of hollow castings are thicker than the thickness of the wax pattern. This cast metal dilation phenomenon is unusual. Shrinkage of metals compared to the pattern dimension is familiar in the casting world. The same abnormalities in the repeated investigation at different sites were observed. All the studies and experiments were organized to explain the reason hidden behind the phenomenon.
    Źródło:
    Archives of Foundry Engineering; 2023, 23, 1; 17--24
    1897-3310
    2299-2944
    Pojawia się w:
    Archives of Foundry Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Static Local Field Factor and Ground State Properties of Interacting Electron Gas
    Autorzy:
    Sarkar, A.
    Haldar, S.
    Roy, D.
    Sen, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/2038378.pdf
    Data publikacji:
    2004-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    71.10.-w
    71.45.Gm
    Opis:
    In the most general case, the calculation of the static local field factor G(q) for the unpolarised electron gas requires the knowledge of exchange-correlation energy functionals for both the parallel and antiparallel relative spin orientations of the electron gas system. Accurate density interpolation formulae using the quantum Monte Carlo data of Ceperley-Alder for the correlation energy of electron gas in both the "para" and "ferro" states, respectively, in the given density range are used for the calculation of G( q). Fulfilment of relevant consistency criteria is ensured and the local field factor so obtained renders significant improvement of ab initio pseudopotential calculation of effective interaction of Al. The Levin like interpolant of the correlation energy Ceperley-Alder data has been further used to study the ground state properties of the electron gas. It is also noted that a better understanding of the interacting electron gas properties requires a more accurate spin interpolation formula for the correlation energy than the existing ones.
    Źródło:
    Acta Physica Polonica A; 2004, 106, 4; 497-514
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Conjugate heat and mass transfer on fluctuating mixed convection flow along a vertical wedge with thermal radiation
    Autorzy:
    Firoza, M. N.
    Roy, N. C.
    Hossain, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/264573.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    mixed convection
    thermal radiation
    vertical wedge
    promieniowanie cieplne
    przepływ ciepła
    niska częstotliwość
    Opis:
    We study the boundary layer characteristics of heat and mass transfer flow past a vertical wedge in the presence of thermal radiation. The surface temperature and the species concentration are assumed to be oscillating in the magnitude but not in the direction of oncoming flow velocity. The governing equations have been solved by two distinct methods, namely, the straightforward finite difference method for the entire frequency range, and the series solution for the low frequency range and the asymptotic series expansion method for the high frequency range. Numerical solutions have been presented in terms of the amplitudes and phase angles of the skin friction, the rate of heat transfer and the mass transfer with the variations of Richardson’s number, the Prandtl number, the conduction–radiation parameter, the surface temperature parameter and the Schmidt number. Furthermore, the effects of these parameters are examined in terms of the transient skin friction, heat transfer and mass transfer.
    Źródło:
    International Journal of Applied Mechanics and Engineering; 2017, 22, 3; 539-565
    1734-4492
    2353-9003
    Pojawia się w:
    International Journal of Applied Mechanics and Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A closed-loop power controller model of series-resonant-inverter-fitted induction heating system
    Autorzy:
    Pal, P.
    Roy, D.
    Datta, A.
    Sadhu, P. K.
    Banerjee, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/141721.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    induction heating
    power controller
    PID
    series resonant inverter
    MATLAB
    Opis:
    This paper presents a mathematical model of a power controller for a high-frequency induction heating system based on a modified half-bridge series resonant inverter. The output real power is precise over the heating coil, and this real power is processed as a feedback signal that contends a closed-loop topology with a proportional-integral-derivative controller. This technique enables both control of the closed-loop power and determination of the stability of the high-frequency inverter. Unlike the topologies of existing power controllers, the proposed topology enables direct control of the real power of the high-frequency inverter.
    Źródło:
    Archives of Electrical Engineering; 2016, 65, 4; 827-841
    1427-4221
    2300-2506
    Pojawia się w:
    Archives of Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Physical and biochemical properties of selected tropical fruits
    Autorzy:
    Athmaselvi, K.A.
    Jenney, P.
    Pavithra, C.
    Roy, I.
    Powiązania:
    https://bibliotekanauki.pl/articles/24720.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Instytut Agrofizyki PAN
    Tematy:
    physical property
    biochemical property
    tropical fruit
    fruit
    guava
    sapota zob.mamey sapote
    mamey sapote
    papaya
    Opis:
    This study was conducted to determine the phy- sical and biochemical properties of guava, sapota, and papaya. The physical properties studied were: dimensions, shell ratio, surface area, bulk and true density, porosity, sphericity, packing coeffi- cient, aspect ratio, and roundness index. The specific heat at various mass fractions, biochemical properties like pH, titratable acidity, total soluble solids, and colour analysis were studied for fruit pulps. The viscosity of fruits was studied at various mass fractions. The high sphericity of guava and sapota indicated that those fruits had high rolling capability, which is an important factor for designing hoppers. Bioch emical analysis showed that sapota was the sweetest fruit amongst the three studied.
    Źródło:
    International Agrophysics; 2014, 28, 3
    0236-8722
    Pojawia się w:
    International Agrophysics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sequence of post-moult exoskeleton hardening preserved in a trilobite mass moult assemblage from the Lower Ordovician Fezouata Konservat-Lagerstätte, Morocco
    Autorzy:
    Drage, H.B.
    Vandenbroucke, T.R.A.
    Van Roy, P.
    Daley, A.C.
    Powiązania:
    https://bibliotekanauki.pl/articles/20934.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Opis:
    Euarthropods have a tough exoskeleton that provides crucial protection from predation and parasitism. However, this is restrictive to growth and must be periodically moulted. The moulting sequence is well-known from extant arthropods, consisting of: (i) the long inter-moult stage, in which no changes occur to the hardened exoskeleton; (ii) the pre-moult stage where the old exoskeleton is detached and the new one secreted; (iii) exuviation, when the old exoskeleton is moulted; and (iv) the post-moult stage during which the new exoskeleton starts as soft, thin, and partially compressed and gradually hardens to the robust exoskeleton of the inter-moult stage. Trilobite fossils typically consist of inter-moult carcasses or moulted exuviae, but specimens preserving the post-moult stage are rare. Here we describe nine specimens assigned to Symphysurus ebbestadi representing the first group of contemporaneous fossils collected that preserve all key stages of the moulting process in one taxon, including the post-moult stage. They were collected from a single lens in the Tremadocian part of the Fezouata Shale Formation, Morocco. Based on cephalic displacement and comparison to other trilobite moults, one specimen appears to represent a moulted exoskeleton. Four specimens are typical inter-moult carcasses. Four others are wrinkled and flattened, with thin exoskeletons compared to inter-moult specimens, and are considered post-moult individuals. These S. ebbestadi specimens illuminate the preservation and morphology of the post-moulting stage, characterised by strong anterior-posterior exoskeleton wrinkling, as well as overall body flattening and reduced visibility of thoracic articulations. Being found in the same lens, these specimens likely represent the first preserved in-the-act mass moulting event. The displayed sequence of moulting suggests the moulting process in trilobites was comparable to modern arthropods, and conserved within euarthropod evolutionary history.
    Źródło:
    Acta Palaeontologica Polonica; 2019, 64, 2
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Water erosion in the catchment basin of the Jeleni Brook
    Erozja wodna w zlewni Potoku Jeleniego
    Autorzy:
    Koćmit, A.
    Podlasiński, M.
    Roy, M.
    Tomaszewicz, T.
    Chudecka, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/293338.pdf
    Data publikacji:
    2006
    Wydawca:
    Instytut Technologiczno-Przyrodniczy
    Tematy:
    czynniki erozji
    erozja uprawowa
    erozja wodna
    osady erozyjne
    straty gleby
    erosion factors
    erosion sediments
    soil losses
    tillage erosion
    water erosion
    Opis:
    The study on water erosion in the catchment basin of the Jeleni Brook was carried out in the years 1995-1999. The catchment of the Jeleni Brook has complex relief, receives frequent precipitations and thus is more threatened by water erosion. Soil cultivation and water from quickly melting snow can also be the factors affecting soil erosion. Waters from the melting snow produce rills of the following dimensions (mean values): width from 11.5 to 13.6 cm, depth - from 6.4 to 7.1 cm and length - from 39 to 112 m. The mean values of soil losses vary from 0.5 to 2.02 t·ha-¹. Erosion caused by intensive storm precipitation occurs less frequently but makes much higher soil losses. One of the registered incidents shows that 51.6 t·ha-¹ (4.5 mm of soil layer) can be washed out from the area of 0.66 ha. Combined effect of outwashing and ploughing in lower parts of slopes created new forms of relief such as agricultural terraces (escarps). Agricultural terraces assume the shape of scarps up to 2 m high and of different length (e.g. 150 m) along with the land use borderlines between e.g. forest and field or field and grassland. Agriculturally used soils within this catchment need protection based mainly on agrotechnical measures or on alteration of land use. Some areas should be afforested.
    W latach 1995-1999 rejestrowano osady erozyjne i żłobiny na gruntach ornych w terenie czołowomorenowym w zlewni rolno-leśnej Potoku Jeleniego. Obszar zlewni wyróżnia się spośród innych intensywną rzeźbą młodoglacjalną (zbocza o znacznych spadkach) i częstszym występowaniem opadów intensywnych - burzowych, przez co jest silniej zagrożony erozją wodną. Do czynników erozyjnych kształtujących erozję wodną należy zaliczyć także agrotechnikę (niekorzystne uprawy rzędowe roślin) i pojawienie się wczesnowiosennych wód roztopowych. Erozja wodna przybiera formę spłukiwania powierzchniowego o nasileniu od słabego do umiarkowanego lub średniego według 5-stopniowej skali przyjętej w Polsce. Erozja powodowana wodami topniejącego śniegu wykształca żłobiny o wymiarach (według wartości średnich): szerokość 11,5-13,6 cm, głębokość 6,4-7,1 cm długość 39-112 m. Średnia wielkość zmywu glebowego wyniosła 0,5-2,02 t·ha-¹. Opady burzowe pojawiają się rzadziej, lecz przyczyniają się do silniejszego rozwoju procesów erozji - przybiera ona bardziej wyraziste formy żłobinowe lub nawet formę zmycia warstwowego, gdy cała warstwa gleby jest odtransportowana z pola (np. 4,5 mm, na powierzchni 0,66 ha). Zarejestrowany zmyw gleby wyniósł w takim przypadku 51,6 t·ha-¹. Zmyty materiał glebowy podlega daleko idącej segregacji w obrębie stożka erozyjnego i wykazuje odpowiednio zmienione właściwości chemiczne. Pierwiastki chemiczne podlegają przy tym transportowi związanemu z cząsteczkami glebowymi lub w formie rozpuszczonej i wtedy mogą odpływać poza granice erodowanego pola, do sieci hydrograficznej. Pierwotną przyczyną uruchomienia się procesów erozji wodnej było wylesienie tych obszarów dokonane w średniowieczu i objęcie ich użytkowaniem rolniczym. Według danych historycznych można szacować okres po wylesieniu (okres użytkowania rolniczego) na około 600 lat. W tym czasie na procesy erozji wodnej nałożyły się procesy erozji uprawowej związane z uprawą gleb, pracą narzędzi rolniczych, a szczególnie w ostatnich stuleciach - z pracą pługa. Sumowanie się efektów zmycia i naorywania gleby w dolnych częściach zboczy wytworzyło nowe formy rzeźby terenu, tzw. terasy rolne. Terasy te przybierają formę skarp o wysokości do 2 m i różnej długości (np. 150 m) o przebiegu zgodnym z granicą użytkowania, na styku las - pole, pole - użytek zielony, lub po granicy własności. W tym ostatnim przypadku skarpa powstaje przez podcięcie zbocza i odprowadzanie materiału glebowego w dół. Stwierdzono łącznie 11,5 km skarp daje to wskaźnik zagęszczenia 2,45 km·km-². Gleby użytkowane rolniczo w granicach zlewni wymagają działań ochronnych, głównie z wykorzystaniem zabiegów agrotechnicznych, a niekiedy także zmiany sposobu użytkowania. Niektóre obszary powinny być przeznaczone pod zalesienie.
    Źródło:
    Journal of Water and Land Development; 2006, 10; 121-131
    1429-7426
    2083-4535
    Pojawia się w:
    Journal of Water and Land Development
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Comparative Ergonomics Postural Assessment of Potters and Sculptors in the Unorganized Sector in West Bengal, India
    Autorzy:
    Sahu, S.
    Moitra, S.
    Maity, S.
    Pandit, A. K.
    Roy, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/89972.pdf
    Data publikacji:
    2013
    Wydawca:
    Centralny Instytut Ochrony Pracy
    Tematy:
    ergonomics
    posture
    musculoskeletal disorders
    low back pain
    REBA
    RULA
    ergonomia
    pozycja przy pracy
    choroby narządów ruchu
    nerwoból okolicy grzbietowej
    Opis:
    Potters and sculptors perform their work in very awkward postures. The purpose of this study was to analyse these postures. The modified Nordic questionnaire was used to analyse musculoskeletal discomfort. Rapid entire body assessment (REBA) and rapid upper limb assessment (RULA) were used to evaluate the subjects' postures. There were no significant differences between times of discomfort and the group of subjects. However, there were significant differences in discomfort in different body parts. The analysis indicated that various body postures were harmful to the subjects and that there were profound deviations from natural curvature of various body parts due to awkward body postures. Ergonomics intervention was required to improve the quality of life.
    Źródło:
    International Journal of Occupational Safety and Ergonomics; 2013, 19, 3; 455-462
    1080-3548
    Pojawia się w:
    International Journal of Occupational Safety and Ergonomics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimal control of a fractional-order enzyme kinetic model
    Autorzy:
    Al-Basir, F.
    Elaiw, A. M.
    Kesh, D.
    Roy, P. K.
    Powiązania:
    https://bibliotekanauki.pl/articles/206336.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    enzyme kinetics
    cooperative phenomenon
    fractional derivative
    mathematical modeling
    Hamiltonian
    optimal control problem
    Opis:
    Enzymes play a significant role in controlling the characteristics of various chemical and biochemical reactions. They act as catalysts that increase the rate of reaction without undergoing any change in quantity. Enzymatic reactions occur through the active sites, which combine with the substrates to form intermediate complexes, subsequently leading to products. An enzyme having two active sites can show cooperative phenomena. Against this background, an enzyme-kinetic mathematical model is formulated using fractional order derivatives. Optimal control mechanism has been incorporated into the fractional-order model system to maximize the product output. Euler-Lagrange optimality conditions are derived for the FOCP (fractional order control problem) using maximum principle. Numerical iterative schemes have been developed to solve the fractional order optimal control problem through Matlab.
    Źródło:
    Control and Cybernetics; 2015, 44, 4; 443-461
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Pulsatilla patens (Ranunculaceae), a perennial herb, is ectomycorrhizal in northeastern Poland and likely shares ectomycorrhizal fungi with Pinus sylvestris
    Autorzy:
    Hoeksema, J.
    Roy, M.
    Laska, G.
    Sienkiewicz, A.
    Horning, A.
    Abbott, M.J.
    Tran, C.
    Mattox, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/59306.pdf
    Data publikacji:
    2018
    Wydawca:
    Polskie Towarzystwo Botaniczne
    Opis:
    The sharing of species of ectomycorrhizal fungi (EMF) among different co-occurring host plant species could allow the formation of common mycorrhizal networks, which can alter plant–plant interactions and succession. Such sharing of EMF among woody species is thought to be common in many forests, but very few herbaceous plants form EMF, so they are assumed to be excluded from EMF networks in forests. We studied the EMF on roots of a common coniferous tree, Pinus sylvestris, and a co-occurring rare herbaceous perennial plant, Pulsatilla patens (Ranunculaceae), in northeastern Poland. We examined roots from co-occuring P. sylvestris and P. patens, visually classified EMF into morphotypes, studied tissue sections of mycorrhizal structures using compound microscopy, and used DNA sequencing to identify the fungi. On both host plant species, we observed EMF colonization, with colonized root tips exhibiting a swollen appearance, as well as a variety of colors and textures of fungal mycelium covering and emanating from those swollen tips. Sectioning and microscopic examination of an EMF morphotype common on P. patens confirmed the presence of a mantle and Hartig net, indicating the likely presence of functional ectomycorrhizal structures. The two most frequent EMF were Cenococcum geophilum and Piloderma olivaceum, and the latter was found to associate with both host plant species. Several EMF found here only on P. patens, including C. geophilum and two Russula species, are known from previous studies to also associate with P. sylvestris and other tree species. The observation of shared EMF between a coniferous tree and an understory herb indicates the potential for common mycorrhizal networks to alter interactions between these two species and may also indicate a unique way in which the distribution and abundance of a rare herbaceous plant may be influenced by shared mutualisms with a common co-occurring woody plant.
    Źródło:
    Acta Societatis Botanicorum Poloniae; 2018, 87, 1
    0001-6977
    2083-9480
    Pojawia się w:
    Acta Societatis Botanicorum Poloniae
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Optimal selection of dental implant for different bone conditions based on the mechanical response
    Autorzy:
    Roy, S.
    Das, M.
    Chakraborty, P.
    Biswas, J. K.
    Chatterjee, S.
    Khutia, N.
    Saha, S.
    Roychowdhury, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/307549.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    wytrzymałość kości
    implanty stomatologiczne
    analiza FEM
    pacjent
    bone condition
    porous dental implant
    FE Analysis
    patient specific
    Opis:
    Bone quality varies from one patient to another extensively; also, Young’s modulus may deviate up to 40% of normal bone quality, which results into alteration of bone stiffness immensely. The prime goal of this study is to design the optimum dental implant considering the mechanical response at bone implant interfaces for a patient with specific bone quality. Method. 3D model of mandible and natural molar tooth were prepared from CT scan data while, dental implants were modelled using different diameter, length and porosity and FE analysis was carried out. Based on the variation in bone density, five different bone qualities were considered. First, failure analysis of implants, under maximum biting force of 250N had been performed; next, the implants, those survived were selected for observing the mechanical response at bone implant interfaces under common chewing load of 120N. Result. Maximum Von Mises stress did not surpass the yield strength of the implant material (TiAl4V). However, factor of safety of 1.5 was considered and all but two dental implants survived the design stress or allowable stress. Under 120N load, distribution of Von Mises stress and strain at the bone-implant interface corresponding to the rest of the implants for five bone conditions were obtained and enlisted. Conclusion. Implants, exhibiting interface strain within 1500-3000 microstrain range show the best bone remodelling and osseointegration. So, implant models, having this range of interface strains were selected corresponding to the particular bone quality. A set of optimum dental implants for each of the bone qualities were predicted.
    Źródło:
    Acta of Bioengineering and Biomechanics; 2017, 19, 2; 11-20
    1509-409X
    2450-6303
    Pojawia się w:
    Acta of Bioengineering and Biomechanics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Study of Thermal Comfort Properties of Different Kinds of Polyester Knitted Fabrics
    Badanie właściwości komfortu termicznego różnych rodzajów dzianin poliestrowych
    Autorzy:
    Mohapatra, Shradhanjali
    Vidya, T.
    Kumar, D. Vasanth
    Rajwin, A. Jebastin
    Babu, V. Ramesh
    Prakash, C.
    Shah, B. Anas
    Roy, Reetuparna
    Powiązania:
    https://bibliotekanauki.pl/articles/2056314.pdf
    Data publikacji:
    2021
    Wydawca:
    Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
    Tematy:
    comfort
    knitted fabric
    microdenier polyester
    polyester
    single jersey
    thermal comfort
    komfort
    dzianina
    poliester microdenier
    poliester
    komfort termiczny
    Opis:
    This research focused on the thermal comfort behaviour of polyester with respect to the type of yarn (spun, micro denier, continuous filament and hollow), linear density of the yarn (111 and 166 dtex), and the loop length of knitted fabric (0.25, 0.27 and 0.29 cm).The air permeability of continuous filament yarn fabric and micro denier yarn knitted fabrics was noted to be higher than that of spun yarn knitted fabrics. 111 dtex micro denier yarn fabric has the highest air permeability and 111 dtex spun yarn fabric the lowest air permeability value among all the other fabric samples. Comparatively, coarser spun yarn fabric has lower air permeability characteristics than finer microdenier fabric.The water permeability of the fabric shows a significant difference between the spun yarn, continuous filament yarn and Micro denier yarn knitted fabrics and between the linear density of the yarn. The water vapour permeability of spun yarn of 166 dtex single jersey fabric is higher, while the water vapour permeability of continuous filament yarn fabric of 166 dtex is lower. The thermal conductivity value is high for continuous filament polyester fabric of 100 D and low for microdenier polyester fabric of 166 dtex. Based on the statistical analysis, it is clearly shown that there are significant differences between the three different polyester yarn fabrics of two different denier of the same fabric. Furthermore, the count and different polyester yarn affect the comfort properties of single jersey fabrics.
    Badania koncentrowały się na zachowaniu komfortu cieplnego poliestru w odniesieniu do rodzaju przędzy, gęstości liniowej przędzy (111 dtex i 166 dtex) oraz długości pętelki dzianiny (0,25 cm, 0,27 cm oraz 0,29 cm). Zbadano właściwości wytworzonych dzianin takie jak: przepuszczalność powietrza, wody, pary wodnej oraz przewodność cieplną, a wyniki poddano analizie statystycznej.
    Źródło:
    Fibres & Textiles in Eastern Europe; 2021, 5 (149); 50--55
    1230-3666
    2300-7354
    Pojawia się w:
    Fibres & Textiles in Eastern Europe
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Evidence for the invalidity of the Wingate test for the assessment of peak power, power decrement and muscular fatigue
    Autorzy:
    Robergs, Robert A
    Kennedy, David
    Gibson, Ann L.
    Zuhl, Micah
    Hsu, Hung-Sheng
    Beam, Jason
    Salgado, Roy M.
    White, Ailish C.
    Majumdar, Aditi
    Lawson, Steve
    Estrada, Edson
    Sierra, Gustavo
    Powiązania:
    https://bibliotekanauki.pl/articles/1054919.pdf
    Data publikacji:
    2015
    Wydawca:
    Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
    Tematy:
    cadence
    ergometry
    fatigue
    force
    motor unit recruitment
    Opis:
    We hypothesized that the protocol-induced initial cadence of the WAnT is too high to allow high muscle force production and peak power generation. Twenty endurance, strength or power trained subjects (9 male, 11 female) completed two 30 s maximal exertion stationary cycle ergometer tests involving the traditional peak cadence start (TRAD) vs. a stationary start (STAT). Inertia corrected mechanical power, cadence, EMG from the vastus lateralis, and applied force to the pedals were measured continuously throughout both tests. Peak power was higher during TRAD; 11.32 ±1.41 vs. 10.40 ±1.35 Watts/kg (p < 0.0001), as was peak cadence; 171.4 ±16.3 vs. 120.9 ±15.1 rev/min (p < 0.0001). However, during TRAD EMG root mean squared (rms) increased continuously throughout the test, force applied to the pedals increased from 1 to 3 s (0.73 ±0.27 vs. 0.90 ±0.39 N/kg; p = 0.02) and thereafter remained relatively stable. EMG mean frequency also increased from 1 to 3 s, but then decreased throughout the remainder of the test. During TRAD, mechanical power decreased near immediately despite increasing EMG rms, EMGmean frequency and force application to the pedals. The initial 10 s of data from the WAnT is invalid. We recommend that intense cycle ergometer testing should commence with a stationary start.
    Źródło:
    Central European Journal of Sport Sciences and Medicine; 2015, 10, 2; 63-78
    2300-9705
    2353-2807
    Pojawia się w:
    Central European Journal of Sport Sciences and Medicine
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
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