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Wyszukujesz frazę "Hernandez, L." wg kryterium: Autor


Tytuł:
Evaluation of Different Scales for Measurement of Perceived Physical Strain During Performance of Manual Tasks
Autorzy:
Hernandez, L.
Alhemood, A.
Genaidy, A. M.
Karwowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/90830.pdf
Data publikacji:
2002
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
load handling
perception
psychophysics
practical methodologies
psychologia pracy
mierzenie pracy i wysiłku
pozycja przy pracy
zmęczenie fizyczne
percepcja
prace ręczne
Opis:
The main objective of this study was to evaluate different scales of perceived strain during the performance of various physical tasks. A total of 52 male and female participants took part in 4 experiments to achieve the study objective. The results suggest that a bipolar comfort-discomfort scale is a more appropriate instrument than a discomfort scale for assessing cumulative physical stresses at work, especially at the beginning of the shift. For assessing discomfort at the end of the work shift, a unipolar scale may also be used. On the basis of the obtained results, red, green, and yellow zones are suggested to establish priorities for work redesign efforts in ergonomic control programs.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2002, 8, 4; 413-432
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On \(\ell_{q}\)-strictly singular operators on variable exponent spaces
Autorzy:
Buelga, Carlos
Hernandez, Francisco L.
Powiązania:
https://bibliotekanauki.pl/articles/746291.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Matematyczne
Tematy:
Variable exponent spaces, strictly singular operators
Opis:
Strictly singular operators on variable exponent (or Nakano) function spaces \(L^{p\left(\cdot\right)}\) are characterized in terms of being \(\ell_{q}\)-strictly singular for the values \(q\) in the essential range \(R_{p\left(\cdot\right)}\) of the exponent function. This extends a result of L. Weiss [On perturbations of Fredholm operators in \(L_{p}\)-spaces, Proc. Amer. Math. Soc. 67 (1977), 287-292] for \(L^{p}\)-spaces.
Źródło:
Commentationes Mathematicae; 2015, 55, 2
0373-8299
Pojawia się w:
Commentationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ethylene mediates in the early oxidative stress induced by mercury
Autorzy:
Montero-Palmero, M.
Martin-Barranco, A.
Alonso, J.
Escobar, C.
Hernandez, L.
Powiązania:
https://bibliotekanauki.pl/articles/81164.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
oxidative stress
plant
mercury
homeostasis
reactive oxygen species
alfalfa
Medicago sativa
1-methylcyclopropene
NADPH oxidase
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 2
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Engineering the optical and mechanical properties exhibited by a titanium dioxide thin film with gold nanoparticles
Autorzy:
Morales-Bonilla, S
Torres-Torres, C
Trejo-Valdez, M
Torres-Torres, D
Urriolagoitia-Sosa, G
Hernandez-Gomez, L H
Urriolagoitia-Calderon, G
Powiązania:
https://bibliotekanauki.pl/articles/174855.pdf
Data publikacji:
2013
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical Kerr effect
nonlinear optics
nanomaterials
Opis:
Thermo-optic and electrostrictive contributions to the nonlinear refractive index were observed in a titanium dioxide thin film with embedded gold nanoparticles. A sol–gel method was employed for preparing thin solid film samples. The nanosecond nonlinear optical properties and the Young’s modulus parameter were changed by shifting the optical absorption band associated with the localized surface plasmon of resonance of the gold nanoparticles with platinum. The third order nonlinear optical phenomena exhibited by the sample were induced by the second harmonic of a Nd-YAG laser with 532 nm wavelength; the nonlinear optical measurements were obtained by monitoring the transmittance and the amplitude modification for the vectorial components of the electric fields in a two-wave interaction. Optical evaluations were confirmed considering a straightforward measurement of the change in the refractive index of the sample when the sample was located in a Michelson interferometer.
Źródło:
Optica Applicata; 2013, 43, 4; 651-661
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Gateaux differentiable bump functions
Autorzy:
L. Hernández, Francisco
Troyanski, Stanimir
Powiązania:
https://bibliotekanauki.pl/articles/1287699.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Opis:
It is shown that the order of Gateaux smoothness of bump functions on a wide class of Banach spaces with unconditional basis is not better than that of Fréchet differentiability. It is proved as well that in the separable case this order for Banach lattices satisfying a lower p-estimate for 1≤ p < 2 can be only slightly better.
Źródło:
Studia Mathematica; 1996, 118, 2; 135-143
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the representation of uncountable symmetric basic sets and its applications
Autorzy:
L. Hernandez, Francisco
Troyanski, Stanimir
Powiązania:
https://bibliotekanauki.pl/articles/1292447.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
symmetric basis
Orlicz sequence spaces
Lorentz sequence spaces
Opis:
It is shown that every uncountable symmetric basic set in an F-space with a symmetric basis is equivalent to a basic set generated by one vector. We apply this result to investigate the structure of uncountable symmetric basic sets in Orlicz and Lorentz spaces.
Źródło:
Studia Mathematica; 1993, 107, 3; 287-304
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin Frustration in Some Magnetic Compounds
Autorzy:
Szytuła, A.
Gondek, Ł.
Penc, B.
Hernandez-Velasco, J.
Powiązania:
https://bibliotekanauki.pl/articles/2038386.pdf
Data publikacji:
2004-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.10.Nr
75.25.+z
75.50.Ee
Opis:
In the paper the results of the powder neutron diffraction measurements of RAuIn (R = Ce, Tb, Dy, and Er) and ZnFe$\text{}_{2}$O$\text{}_{4}$ compounds at low temperatures are presented. For the RAuIn compounds, which crystallize in the hexagonal ZrNiAl-type structure, the rare-earth moments lie in the ab-plane and form a typical triangle non-collinear structure. ZnFe$\text{}_{2}$O$\text{}_{4}$ has the normal spinel structure in which the Fe$\text{}^{3+}$ ions occupy the B sites, forming the corner-shared tetrahedra of the Fe spins. At low temperatures experimental data indicate the coexistence of the long-range and the short-range magnetic order. The obtained results suggest that the important factor which influences the magnetic ordering in these compounds is geometrical frustration of magnetic moments.
Źródło:
Acta Physica Polonica A; 2004, 106, 5; 583-591
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microdamage distribution in fatigue fractures of bone allografts following gamma-ray exposure
Autorzy:
Presbítero, G.
Hernandez-Rodríguez, M. A. L.
Contreras-Hernandez, G. R.
Vilchez, J. F.
Susarrey, O.
Gutiérrez, D.
Powiązania:
https://bibliotekanauki.pl/articles/307297.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rozkład Weibulla
pękanie zmęczeniowe
promieniowanie gamma
kość korowa
mikrouszkodzenia
allografts
Weibull distribution
fatigue fracture
gamma radiation
cortical bone
microdamage
Opis:
Although clear evidence of significant differences in bone properties have been extensively studied, results vary under the ranges usually used for sterilization purposes (25-35 kGy). Hence, the aim of this work was the study of the mechanical properties and microdamage development of human bones used as allografts following gamma-ray exposure, followed by an extensive statistical analysis of microdamage effects in fatigue behaviour. Methods: Specimens of the cortical region of human femurs were exposed to 15-25 kGy and 26-30 kGy radiation levels, then they were subjected to compression fatigue tests until fracture. The fatigue life was determined in relation to the radiation level, and the evolution of microdamage was assessed through fluorescence microscopy in order to calculate characteristic lengths of microcracks. Results: Significant differences in fatigue life were detected (p < 0.05) between non-radiated (control) and radiated specimens, resulting in a drastic 89.2% fatigue life reduction of the 15-25 kGy group, and 95.3% in the 26-30 kGy group in comparison to the control. Microdamage analysis showed a considerable increase in microcrack lengths when bone was exposed to gamma radiation, which may indicate that bones used as allografts could fracture at some point when subjected to in vivo loading conditions. Conclusions: The results of our research indicate that, even if a range of 15-25 kGy is suggested to sterilize bone allografts, such practice needs to be reconsidered. In addition, with use of Weibull distribution, this work describes the conditions in which microcracks grow towards the fracture of bones in relation to the decrease in their mechanical properties.
Źródło:
Acta of Bioengineering and Biomechanics; 2017, 19, 4; 43-53
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximate mechanical behavior analysis of a thick-wall metallic liner reinforced with composites, submitted to internal pressure
Autorzy:
Vargas-Rojas, E.
Palacios-Montúfar, C.
Hernández-Moreno, H.
González-Velázquez, J. L.
Powiązania:
https://bibliotekanauki.pl/articles/200013.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mechanical behavior analysis
thick-wall metallic liner
composites
internal pressure
analiza zachowania
ściana
kompozyty
ciśnienie wewnętrzne
Opis:
This study aims to simulate and to analyze the elastic and the damage behavior of a reinforced metallic liner (RML) by means of a computational tool, in order to aid in the design of high specific-stiffness and -strength barrels for heavy-duty hydraulic applications. Case studies for the program validation are undertaken using an AISI 1026 or St52.3 steel tubing reinforced with a polymeric composite of glass fiber and epoxy resin, wound in a hoop pattern. The mechanical behavior of the RML under internal pressure with no-end effects is predicted by means of strain measurements at the outermost layer. The mathematical model is based on the Classical Lamination Theory (CLT) improved with kinematic relationships that allow to introduce curvature effects. Numerical results based on experimental measurements show that the reinforcement is effective, allowing to considerably augment the maximum bearable pressure with respect to a non-reinforced metallic liner (nRML), without important weight or cost increase.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2016, 64, 1; 219-233
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Approach to Measurement of Frequency Shifts Using the Principle of Rational Approximations
Autorzy:
Murrieta-Rico, F. N.
Petranovskii, V.
Sergiyenko, O. Y.
Hernandez-Balbuena, D.
Lindner, L.
Powiązania:
https://bibliotekanauki.pl/articles/220851.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
frequency measurement
rational approximations
sensors
Opis:
When a frequency domain sensor is under the effect of an input stimulus, there is a frequency shift at its output. One of the most important advantages of such sensors is their converting a physical input parameter into time variations. In consequence, changes of an input stimulus can be quantified very precisely, provided that a proper frequency counter/meter is used. Unfortunately, it is well known in the time-frequency metrology that if a higher accuracy in measurements is needed, a longer time for measuring is required. The principle of rational approximations is a method to measure a signal frequency. One of its main properties is that the time required for measuring decreases when the order of an unknown frequency increases. In particular, this work shows a new measurement technique, which is devoted to measuring the frequency shifts that occur in frequency domain sensors. The presented research result is a modification of the principle of rational approximations. In this work a mathematical analysis is presented, and the theory of this new measurement method is analysed in detail. As a result, a new formalism for frequency measurement is proposed, which improves resolution and reduces the measurement time.
Źródło:
Metrology and Measurement Systems; 2017, 24, 1; 45-56
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The mechanical properties of PVD coatings deposited on nitrided CoCrMo alloy
Właściwości mechaniczne powłok PVD osadzanych na azotowanym stopie CoCrMo
Autorzy:
Ortega-Saenz, J.A.
Hernandez-Rodriguez, M.A.L.
Michalczewski, R.
Smolik, J.
Szczerek, M.
Powiązania:
https://bibliotekanauki.pl/articles/187966.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
stop CoCrMo
azotowanie
powłoka PVD
Co-Cr-Mo alloy
nitriding
PVD coatings
Opis:
The paper concerns the evaluation of mechanical properties of the composite: 'nitrided layer-PAPVD coating' created on CoCrMo alloy intended for biotribological applications. Five nitriding processes with varying nitriding potential (p(N2/H2) =1.0, 1.5, 2.0, 2.5 and 3.0) were selected for optimising. The modulus of elasticity and nanohardness of nitrided layers were measured by nanoindentation. Cross-sections were examined by means of scanning electron microscopy (SEM) in order to determine the thickness and the uniformity of the affected zone after nitriding. The change in surface roughness was studied with the help of 3D roughness parameters obtained by atomic force microscopy (AFM) and the phase composition was determined by means of X-ray diffraction (XRD). It was found that the most suitable properties of the surface layer were achieved by nitriding at p(N2/H2) = 2.5. CrN as well as multilayer (TiN/CrN)x3 PAPVD coatings were deposited onto the substrates with and without nitiriding for evaluation of the nitriding effect on the adhesion. CoCrMo alloy nitrided sample was included for comparison. All these conditions were characterised by means of AFM, nanohardness, SEM, and scratch test. The duplex technology applied to CoCrMo orthopaedic alloy allows for a significant increase of the adhesion of the PAPVD coatings and the improvement of the load carrying capacity of the CoCrMo orthopaedic alloy.
Artykuł dotyczy oceny mechanicznych właściwości kompozytu warstwa azotowana/powłoka PVD utworzonego na stopie ortopedycznym CoCrMo stosowanym w aplikacjach biotribologicznych. Przeprowadzono optymalizację procesu azotowania dla potencjału azotowego wynoszącego (p(N2/H2) = 1,0, 1,5, 2,0, 2,5 i 3,0). Dla uzyskanych warstw azotowanych wykonano pomiary modułu elastyczności i nanotwardości. W celu oceny grubości i jednorodności uzyskanych warstw wykonano obserwacje mikroskopowe (SEM) przekrojów poprzecznych. Zmiany chropowatości powierzchni zostały ocenione za pomcą stereometrycznych parametrów mierzonych z wykorzystaniem mikroskopii sił atomowych (AFM), natomiast zmiany składu fazowego za pomocą dyfrakcji rentgenowskiej (XRD). Uzyskane wyniki wskazały, że najkorzystniejsze właściwości warstwy wierzchniej uzyskano dla potencjału p(N2/H2), wynoszącego 2,5. Dokonano oceny wpływu azotowania podłoża na adhezję powłoki CrN oraz (TiN/CrN)x3 osadzanych metodą PAPVD z wykorzystaniem technik AFM, nanotwardościomierza, SEM oraz scratchtestu. Wykazano, że technologia duplex stosowana do ortopedycznego stopu CoCrMo? pozwala na znaczne zwiększenie adhezji powłok PAPVD oraz poprawę jego właściwości przeciwzużyciowych.
Źródło:
Tribologia; 2010, 3; 173-186
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect on Highly Cr-Substituted Manganite Nd$\text{}_{0.6}$C a$\text{}_{0.4}$(Mn$\text{}_{0.5}$Cr$\text{}_{0.5}$)O$\text{}_{3}$
Autorzy:
Gamari-Seale, H.
Troyanchuk, I. O.
Bushinsky, M. V.
Stefanopoulos, K. L.
Hernandez-Velasco, J.
Powiązania:
https://bibliotekanauki.pl/articles/2037098.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.25.+z
75.30.Kz
75.47.Lx
Opis:
Neutron powder-diffraction experiments on the highly Cr-substituted manganite, Nd$\text{}_{0.6}$Ca$\text{}_{0.4}$(Mn$\text{}_{0.5}$Cr$\text{}_{0.5}$)O$\text{}_{3}$, at different temperatures and fields reveal that the structure retains the charge exchange-type of the parent compound, Nd$\text{}_{0.6}$Ca$\text{}_{0.4}$MnO$\text{}_{3}$. It is antiferromagnetic below 200 K and becomes a canted antiferromagnet below 50 K. The Mn and Cr form zig-zag ferromagnetic chains coupled antiferromagnetically in the ac-plane. These are stacked along the b-axis with opposite spins.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 81-86
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Encapsulation of Lactiplantibacillus plantarum and Beetroot Extract with Alginate and Effect of Capsules on Rheological Properties and Stability of an Oil-in-Water Emulsion Model Food
Autorzy:
Bautista Villarreal, Minerva
Castillo Hernández, Sandra Loruhama L.
López Uriarte, Salvador
Barrón González, María Porfiria
Powiązania:
https://bibliotekanauki.pl/articles/16538552.pdf
Data publikacji:
2023-08-28
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
alginate bead
probiotic
co-encapsulation
dressing
storage
bacteria viability
Opis:
Alginate encapsulation is a viable alternative for the preservation of probiotics along the gastric route or within a food product during its shelf life. Furthermore, co-encapsulation with a vegetal material could act as a prebiotic and enhance the viability of the encapsulated probiotic. The rheological properties of dressing-type foods could be altered by adding an ingredient that would affect the quality of the final product. In this investigation, alginate beads loaded with Lactiplantibacillus plantarum and beetroot extract were obtained by two methods (emulsification and extrusion). They were characterized by size and morphology, encapsulation efficiency, and bacteria viability under simulated gastrointestinal conditions. Finally, they were added in an oil-in-water emulsion model food for which rheological properties and probiotic survival were monitored. The encapsulation efficiency ranged from 85.26 to 88%. Morphology and size of capsules varied depending on the method of encapsulation applied. No significant changes were evidenced in the rheological properties of the model food; the viscosity, the particle size (d3,2), and the coalescence rate remained stable after the addition of the capsules. Survival of L. plantarum was significantly higher in the capsules with beetroot extract. These results suggest a prebiotic effect conferred by the beetroot extract when co-encapsulated. It is worth mentioning that the incorporation of capsules with beetroot extract does not cause any destabilization of the model food.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2023, 73, 3; 242-252
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Airborne pollen of Carya, Celtis, Cupressus, Fraxinus and Pinus in the metropolitan area of Monterrey Nuevo Leon, Mexico
Autorzy:
Rocha-Estrada, A
Alvarado-Vazquez, M.A.
Torres-Cepeda, T.E.
Foroughbakhch-Pournavab, R.
Hernandez-Pinero, J.L.
Powiązania:
https://bibliotekanauki.pl/articles/51592.pdf
Data publikacji:
2008
Wydawca:
Instytut Medycyny Wsi
Tematy:
Pinus
pollen grain
Celtis
metropolitan area
airborne pollen
Carya
street
private garden
public park
Mexico
Nuevo Leon
plant
atmosphere
Monterrey
garden
Cupressus
Fraxinus
Źródło:
Annals of Agricultural and Environmental Medicine; 2008, 15, 2
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł

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