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Tytuł:
Zwiększenie trwałości rolek do formowania rur
Increasing tool life of rollers for roll forming of tubes
Autorzy:
Haduch Suski, Z.
Lozano Andrade, J.
García Rodríguez, A.
González, H. R.
Rodríguez, E.
Powiązania:
https://bibliotekanauki.pl/articles/190630.pdf
Data publikacji:
2014
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
rolki
stal narzędziowa
rury
obróbka cieplna
azotowanie
obróbka podzerowa
rolls
tool steels
tubes
heat treatment
nitriding
sub-zero treatment
Opis:
Przemysł wytwarzania rur stosuje różne metody i techniki ich produkcji, jednak formowanie rur stalowych ze szwem ma największe osiągnięcia na rynku. Podstawowe narzędzie do ich formowania, czyli rolki są tradycyjnie wykonywane ze stali narzędziowych o wysokiej zawartości chromu, na przykład stali narzędziowej D2. Jednak jakość rur nowej generacji wykonywanych ze stali o wyższej wytrzymałości i twardości wymaga zastosowania nowych materiałów przewyższających właściwości mechaniczne stali D2. Zaistniała więc konieczność zmian technologii, przeprojektowania narzędzi, przebadania nowych materiałów i opracowania odpowiedniej obróbki cieplnej, zapewniając im dłuższą żywotność i zmniejszenie przestojów w celu spełnienia oczekiwań produkcyjnych. W niniejszym projekcie zostały przeanalizowane i ocenione najlepsze opcje przedstawione na rynku narzędzi do pracy na zimno w celu zwiększenia żywotności istniejących narzędzi (stal D2). Ocenę przeprowadzono w warunkach laboratoryjnych zbliżonych maksymalnie do parametrów produkcyjnych. Wykorzystano tester do badań tribologicznych (T-05) i wykonano badania dynamiczne (próba Charpy'ego). Wykazano przydatność nowych materiałów i możliwość uzyskania oszczędności.
Industries engaged in roll forming of tubes apply different methodologies and innovating technologies in order to perform this task, but tubes with welded seams are more profitable. The basic tooling used to roll-form tubes, or rolls, are usually made of a tool steel with a high Chromium content, namely, D2 steel. However, in order to produce higher quality tubes of high-strength steels, higher mechanical properties than those shown by D2 steel are required. As a consequence, new technologies, designs, materials, and heat treatments have emerged so the new requirements are met. This has a direct impact on the costs incurred and the productivity of metalmechanic industries. In this project, various cold work steels were analysed and compared with D2 steel, in order to improve the tool life of rolls for roll forming of tubes. Tribological testing was done with a T-05 block-on-ring setup with testing conditions similar to those in real life. Charpy testing was done in order to obtain impact toughness. The obtained results are of great importance, because they may result on significant cost reductions.
Źródło:
Tribologia; 2014, 6; 43-66
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Use of phenological and pollen-production data for interpreting atmospheric birch pollen curves
Autorzy:
Jato, V
Rodriguez-Rajo, F.J.
Aira, M.J.
Powiązania:
https://bibliotekanauki.pl/articles/51556.pdf
Data publikacji:
2007
Wydawca:
Instytut Medycyny Wsi
Tematy:
pollen production
Betula pendula
airborne pollen
Betula alba
flowering period
phenology
Betula
Spain
birch pollen
Opis:
Although aerobiological data are frequently used as a fl owering sign in phenological research, airborne pollen counts are infl uenced by a number of factors affecting pollen curves. A study was made about the reproductive biology of birch and environmental factors infl uencing its pollen release and transport, in order to achieve a reliable interpretation of Betula pollen curves. Aerobiological data were recorded in 2002 and 2003 at two sites in NW Spain and phenological observations were carried out on 20 trees from four Betula populations (three Betula alba L. and one B. pendula Roth.). Pollen production was calculated for six Betula alba trees. Chilling and heat requirements for triggering development were calculated. Due to differences in the geographical location, budbreak and fl owering started fi rst in Betula pendula. The fl owering period lasted from 8-13 days. Reduced pollen output per anther and catkin in individual trees in 2003 prompted a marked decline in overall pollen production. Major differences observed in birch pollen curves were attributed to the infl uence both of weather conditions and pollen transport from areas where the fl owering occurs at a different time. Heat requirements calculated using phenological and aerobiological data were similar when the peak pollen- count date was used.
Źródło:
Annals of Agricultural and Environmental Medicine; 2007, 14, 2
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Unconformity surfaces in pelagic carbonate environments : A case from the Middle Bathonian of the Betic Cordillera, SE Spain
Autorzy:
Nieto, L. M.
Rodríguez-Tovar, F. J.
Molina, J. M.
Reolid, M.
Ruiz-Ortiz, P. A.
Powiązania:
https://bibliotekanauki.pl/articles/191710.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Unconformity
pelagic swell
softground
firmground
hardground
Middle-Late Jurassic
Betic External Zone
Opis:
Integrative studies of sedimentary and palaeontological topics for unconformity surfaces are useful in basin analysis. A middle Bathonian unconformity surface in the Ammonitico Rosso facies cropping out in the La Mola Unit (Subbetic Domain, Betic External Zone) was studied by integrating ichnological, palaeotectonic, and sedimentological analyses to decipher sea-level, tectonic, and palaeogeographic conditions during its development. The trace-fossil assemblage mainly consists of the Glossifungites (Thalassinoides, Arenicolites, and Gastrochaenolites) and Trypanites ichnofacies elements. Probable Ophiomorpha represents previous softground stages, Thalassinoides and Arenicolites were formed in firmground, Gastrochaenolites reflects an evolved firmground or early hardground, and Trypanites can be attributed to an incipient hardground. The degree of firmness, relative sea-level position, and continuity of deposition were related. The softground stage corresponds to a fall in relative sea level and continued deposition. The firmground (semi-consolidated substrate) probably reflects an extremely low sea level characterized by non-deposition, whereas the incipient hardground stage indicates an initial phase of relative sea-level rise, with an increase in marine current energy. The presence of two neptunian dyke systems reflects significant tectonic activity related to the transtensional deformation that affected the South Iberian Palaeomargin. Lateral variations in sedimentological and ichnological features recorded at similar discontinuity surfaces in nearby areas were considered and related to differences in bottom topography, with associated changes in sedimentation, and to the variable duration of the hiatus.
Źródło:
Annales Societatis Geologorum Poloniae; 2014, 84, 3; 281-295
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two cases of phase-shifting interferometry for wave front recovery from heterodyne hologram storage: piezoelectric transducer and modulation of polarization
Autorzy:
Rodríguez-Zurita, G.
Vázquez-Castillo, J. F.
Toto-Arellano, N. I.
Calderón-Hernández, G.
Barojas-Gutiérrez, E.
Powiązania:
https://bibliotekanauki.pl/articles/173402.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
holographic interferometry
phase-shifting
polarization
Opis:
Heterodyne holographic interferometry is a well-known interferometric technique for high precision measurements of the phase difference between two recorded wave fronts. These wave fronts are typically registered at a given distance from the object under inspection. Although the affinity of heterodyne techniques with the phase-shifting ones is immediate, reports on concrete implemented set-ups from the former type of techniques as adaptations into the second type seems to be not so widely spread as convenient. To illustrate this point, in this communication we demonstrate two phase-shifting methods as applied to heterodyne holograms, each variant using a different shifting method for phase shifting. One method is based on a conventional piezoelectric stack transducer and the other method comprises modulation of polarization. The alternatives that these two techniques offer could be of direct benefit in dynamic holography.
Źródło:
Optica Applicata; 2017, 47, 4; 579-590
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transcriptome analysis of enzyme activities regulating ROS metabolism in olive (Olea europaea L.) reproductive tissues
Autorzy:
Zafra, A.
Carmona, R.
Jimenez-Quesada, M.
Traverso, J.
Castro, A.
Rodriguez-Garcia, M.
Bautista, R.
Claros, M.
Alche, J.
Powiązania:
https://bibliotekanauki.pl/articles/80459.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
transcriptome
enzyme activity
reactive oxygen species
metabolism
olive
Olea europaea
reproductive tissue
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:
Three-level modulation techniques to reduce instantaneous common mode voltage in induction machines
Autorzy:
Cusidó, J.
Luna, A.
Busquets, S.
Bordonau, J.
Rodríguez, P.
Romeral, L.
Powiązania:
https://bibliotekanauki.pl/articles/262817.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
common mode voltages
multilevel inverter
drive systems
Opis:
Problems on inverter motor drives such as bearing currents are introduced due to common mode voltages. Different solutions are proposed on literature, for two-level or multilevel inverter. Instantaneous zero common mode voltage by using a three-level inverted could be achieved. This paper proposes a commutation strategy that allows zero common mode voltage by using medium vectors, and also a new representation as a plane on the commutation space is defined which is called zero common mode voltage plane. On this defined plane, every turning vector fulfil this property. Simulations and experimental results clearly show method's efficiency.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2007, 13, 2; 33-38
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-dimensional cfd analysis to study the thrust and efficiency of a biologicallyinspired marine propulsor
Autorzy:
Lamas, M. I.
Rodríguez, J. D.
Rodríguez, C. G.
González, P. B.
Powiązania:
https://bibliotekanauki.pl/articles/259319.pdf
Data publikacji:
2011
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fish swimming
marine propulsion
undulating fin
biomimetic
computational fluid dynamics (CFD)
CFD
Opis:
Aquatic animals, which are the result of many millions of years of evolutionary optimization, are very quick, efficient, robust, and versatile. Accordingly, biologically-inspired mechanisms which emulate the movement of animals have recently become very popular. For the efficient design of a propulsion system it is very important to analyze the fluid flow in detail. CFD (Computational Fluid Dynamics) has become a powerful technique to understand the phenomena because it gives extensive information about the fluid flow characteristics. In the present work, a propulsion system consisting of an undulating fin which emulates the fish swimming was built. In order to optimize the mechanism, several undulating configurations were studied using a 3D turbulent CFD model. The thrust, drag, efficiency and hydrodynamic characteristics were analyzed. Furthermore, it was shown that the efficiency and thrust depend strongly on the oscillation frequency, amplitude and wavelength. In order to validate this CFD model, the numerically obtained thrust was successfully compared with experimental results from the laboratory mechanism.
Źródło:
Polish Maritime Research; 2011, 1; 10-16
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thirty-four identifiable airborne fungal spores in Havana, Cuba
Autorzy:
Almaguer, M.
Aira, M.-J.
Rodriguez-Rajo, F.J.
Fernandez-Gonzalez, M.
Rojas-Flores, T.I.
Powiązania:
https://bibliotekanauki.pl/articles/51658.pdf
Data publikacji:
2015
Wydawca:
Instytut Medycyny Wsi
Źródło:
Annals of Agricultural and Environmental Medicine; 2015, 22, 2
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Odyssey of a Diptych. Issues of Authorship and Provenience of the Virgen Dolorosa and the Cristo Coronado de Espinas from the Former Collection in Gołuchów
Wędrówka dyptyku. Problem autorstwa i proweniencji wizerunków „Mater Dolorosa” i „Chrystusa cierniem koronowanego” z dawnej kolekcji w Gołuchowie
Autorzy:
Rojewski, Oskar J.
Diéguez-Rodríguez, Ana
Powiązania:
https://bibliotekanauki.pl/articles/23352235.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Instytut Sztuki PAN
Tematy:
Prymitywiści niderlandzcy
Albrecht Bouts
sztuka XVI w.
Chrystus cierniem koronowany
Mater Dolorosa
Flemish primitives
16th-Century art
Christ Crowned with Thorns
Opis:
This paper aims to gather all information about the diptych of Mater Dolorosa and Christ Crowned with Thorns, which until 2023 stayed in the Provincial Museum of Pontevedra (Museo Provincial de Pontevedra) in Spain. The research addresses two aspects of the diptych: the controversy of its attribution to a circle of Albrecht Bouts or his follower and the diptych’s arrival at the Provincial Museum of Pontevedra. This study explains that this diptych’s former attributions cannot be supported due to his style and the new research about Bout’s workshop practices. Finally, it gathers all the documentary sources about its arrival at the Pontevedra Museum.
Wędrówka dyptyku. Problem autorstwa i proweniencji wizerunków „Mater Dolorosa” i „Chrystusa cierniem koronowanego” z dawnej kolekcji w Gołuchowie. Niniejszy artykuł stanowi analizę dyptyku z przedstawieniami Mater Dolorosa i Chry- stusa cierniem koronowanego, znajdującego się do 2023 r. w kolekcji Museo Provincial de Pontevedra w Hiszpanii. Przeprowadzone badania miały na celu wyjaśnienie dwóch kwestii: kontrowersji związanych z atrybucją dzieła kręgowi Albrechta Boutsa oraz z historią jego identyfikacji i dotarcia na Półwysep Iberyjski. W oparciu o analizę stylistyczną oraz ostatnie badania nad warsztatem rodziny Bouts, Autorzy proponują nową hipotezę na temat pochodzenia obrazów. Badania archiwalne i wnikliwa lek- tura literatury przedmiotu pozwoliły także na wyjaśnienie okoliczności przekazania dyptyku do Muzeum w Pontevedra.
Źródło:
Biuletyn Historii Sztuki; 2023, 85, 1; 47-68
0006-3967
2719-4612
Pojawia się w:
Biuletyn Historii Sztuki
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 influence of information on the prevention of occupational risks and ergonomic requirements in the development of non-traumatic osteomuscular diseases of the shoulder – a pilot study
Autorzy:
Rodríguez-Blanes, Gloria M.
Lobato-Cañón, José Rafael
Sánchez-Payá, José
Ausó-Pérez, José Ramón
Cardona-Llorens, Antonio Francisco J.
Powiązania:
https://bibliotekanauki.pl/articles/2161943.pdf
Data publikacji:
2019-11-15
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
prevention
occupational health
primary healthcare
shoulder
musculoskeletal disorders
cumulative trauma disorders
Opis:
Objectives Shoulder pain associated with upper limb musculoskeletal disorders is an important health problem in clinical practice due to its high prevalence, frequent consultations in primary healthcare and occupational health. Preventive strategies, including information disseminated among workers, can be useful. The aim of this study is to analyze the associations between non-traumatic osteomuscular diseases of the shoulder and the workers’ knowledge of the risks at the workplace and preventive measures developed there, as well as the association with ergonomic requirements. Material and Methods An observational case-control study was carried out on an occupationally active population assisted during 1 year in 1 healthcare center, involving 690 participants. Data were collected through a questionnaire including sociodemographic variables, the workplace, the knowledge of prevention and ergonomic requirements. The independent effect of the variables associated with non-traumatic shoulder pathology was explored through logistic regression. Results In total, 66.7% of the participants stated that they had been informed of the occupational hazards related to their jobs. The following variables were associated with a lower probability of shoulder injuries: male gender, working hours > 9 h/day or > 40 h/week, as well as having information on the risks associated with the workplace, using personal protective equipment, the existence of an occupational risks prevention service and/or risk assessment, the knowledge of the prevention plan, periodic medical examinations, and using one arm or physical force at work. A multivariate analysis revealed that the risk increased with age and lower educational levels, forced postures, repeated gestures, monotony and temporary absences from work. Furthermore, being informed of workplace risks, and using a single arm as well as physical force were shown as independent protective factors. Conclusions Information on both the ergonomic requirements and how to prevent occupational risks is a useful tool for the prevention of non-traumatic shoulder diseases. Preventive policies including health education interventions in the workplace could benefit other developed preventive activities. Int J Occup Med Environ Health. 2019;32(6):825–40
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2019, 32, 6; 825-839
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Telematics in a transportation system based on pipelines in the oil industry, case study of Cuba
Autorzy:
Martinez-Rodriguez, D.
Szpytko, J.
Powiązania:
https://bibliotekanauki.pl/articles/393749.pdf
Data publikacji:
2018
Wydawca:
Polskie Stowarzyszenie Telematyki Transportu
Tematy:
control systems
pipeline transport systems
oil industry
system kontroli
system transportu rurociągów
przemysł naftowy
Opis:
The paper subject is the concept of a system for monitoring the operation of a pipeline transport network using telematics for the needs of the oil industry on a selected example. Transport telematics allows to deliberately influence the proces of moving cargo/ data using the elaborated deliberate decisions, as a result of the prior analysis of information and knowledge obtained using a dispersed system of sensors associated with means of pipeline transport, infrastructure, environment and man. The concept of the process of monitoring the technical condition of pipelines for the purpose of ensuring the required efficiency of the transport system and decisions regarding the process of their operation using a dedicated distributed monitoring system of selected operational parameters will be presented. In particular, the paper will focus on the location and categorization of pipe damages.
Źródło:
Archives of Transport System Telematics; 2018, 11, 2; 30-36
1899-8208
Pojawia się w:
Archives of Transport System Telematics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis of SrTiO3 by the Calcination of SrCO3 and TiO2 Mixtures Intensively Ground by Means of High Energy Milling
Autorzy:
Rocha-Rangel, Enrique
Pech-Rodríguez, Wilian J.
López-Hernández, Juan
Calles-Arriaga, Carlos A.
Armendáriz-Mireles, Eddie N.
Castillo-Robles, José A.
Rodríguez-García, José A.
Powiązania:
https://bibliotekanauki.pl/articles/356247.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
SrTiO3
mechanochemistry
insulating ceramics
perovskite
Opis:
A SrTiO3 electroceramic with perovskite structure was produced by the calcination of a mixture of SrCO3 and TiO2 intensively grounded by high energy milling. For this purpose, raw materials were mixed in stoichiometric amounts in a planetary type mill; the obtained powder mixture was calcined for 2 h at temperatures between 800 and 1300°C. Samples resulting from the calcination were characterized by XRD, FTIR, SEM analysis and electrical measurements. From XRD, it was determined that the SrTiO3 formed presents the cubic structure of perovskite. The complete reaction for SrTiO3 compound formation occurs at 1200°C. Micrograph observations indicate the presence of a homogeneous microstructure with tiny grain size. The measured values of electrical resistivity were within the typical range of insulating materials.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 2; 621-626
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on health risk factors as a basis to implement programs that promote a nutritional culture in students of the la Sabana University
Autorzy:
Rodriguez, S.
Martinez, M.
Segnini, F.
Cajiao, V.
Aivasovsky, I.
Celis, L.G.
Ayala, J.
Rozo, C.
Russi, A.
Girata, V.
Almonacid, C.C.
Powiązania:
https://bibliotekanauki.pl/articles/2087202.pdf
Data publikacji:
2021
Wydawca:
Narodowy Instytut Zdrowia Publicznego. Państwowy Zakład Higieny
Tematy:
health promotion
disease prevention
obesity
non-communicable diseases
healthy lifestyle
Opis:
Background. Nowadays the importance of lifestyles in the prevention of type 2 diabetes and the metabolic syndrome has been largely accertained. Objective. The purpose of our work is to implement programs that promote a nutritional culture in adolescents and young adults of the La Sabana University. Methods. The methodology entailed, after the corresponding informed consent, taking measures of the triceps and supraescapular skinfolds, waist circumference, body mass index (BMI), lean mass, and fat mass. Fasting blood samples were also taken to quantify cholesterol, triglycerides, high density lipoprotein (HDL) and low density lipoprotein (LDL). Results. The results obtained show that of the 165 students, 10.3% were underweight, 13.93% were overweight and 0.6% were obese. With regards to gender, 4.8% of the men and 9% of the women were overweight, 3% of the men and 7.2% of the women were underweight, and 0.6% of the women were obese. The blood chemistry showed that 30% had hypercholesterolemia, 18% hypertriglyceridemia, 17% reported low HDL levels and 67% reported high LDL levels. Of all the cases studied, 40% are at risk of a metabolic syndrome. 60% claimed not to practice any physical activity - especially women who reported 44.70%. Conclusions. These findings have allowed us at the institution to implement a culture of healthy habits. The have also allowed us to identify students with risk factors for type 2 diabetes and metabolic syndrome. This is why the cardio- metabolic monitoring and control based on healthy eating and physical activity are important.
Źródło:
Roczniki Państwowego Zakładu Higieny; 2021, 72, 1; 89-94
0035-7715
Pojawia się w:
Roczniki Państwowego Zakładu Higieny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of ancient forging devices: 3D modelling and analysis using current computer methods
Autorzy:
Rojas-Sola, J. I.
Bouza-Rodríguez, J. B.
Comesaña-Campos, A.
Powiązania:
https://bibliotekanauki.pl/articles/200411.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
forging device
hydraulic trompe
3D modelling
computational fluid dynamics
finite element analysis
urządzenie do kucia
modelowanie 3D
analiza elementów skończonych
Opis:
An ancient forging device in Spain has been studied, namely the forge with a waterwheel and air-blowing tube or hydraulic trompe, found near the village of Santa Eulalia de Oscos (province of Asturias, Spain). Three procedures using ad hoc methods were applied: 3D modelling, finite element analysis (FEA), and computational-fluid dynamics (CFD). The CFD results indicated the proper functioning of the trompe, which is a peculiar device based on the Venturi effect to take in air. The maximum air volume flow rate supplied to the forge by the trompe was shown to be 0.091 m3/s, and certain parameters of relevance in the trompe design presented optimal values, i.e. offering maximum air-flow supply. Furthermore, the distribution of stress over the motion-transmission system revealed that the stress was concentrated most intensely in the cogs of the transmission shaft (a kind of camshaft), registering values of up to 7.50 MPa, although this value remained below half of the maximum admissible work stress. Therefore, it was confirmed that the oak wood from which the motion system and the trompe were made functioned properly, as these systems never exceeded the maximum admissible working stress, demonstrating the effectiveness of the materials used in that period.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2019, 67, 2; 377-390
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
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