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Tytuł:
Foot metastasis as a first clinical manifestation of rectal carcinoma
Autorzy:
Baraniak, J.
Krupski, W.
Sompor, J.
Prystupa, A.
Powiązania:
https://bibliotekanauki.pl/articles/3345.pdf
Data publikacji:
2008
Wydawca:
Instytut Medycyny Wsi
Tematy:
foot
bone
metastasis
clinical syndrome
rectal carcinoma
human disease
colorectal carcinoma
Źródło:
Journal of Pre-Clinical and Clinical Research; 2008, 02, 2
1898-2395
Pojawia się w:
Journal of Pre-Clinical and Clinical Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigations and finite element modelling of a suggested prosthetic foot
Autorzy:
Jweeg, M.J.
Hassan, A.K.
Almudhaffa, M.M.
Powiązania:
https://bibliotekanauki.pl/articles/24200551.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
prosthetic foot design
Kenaf fibre
dynamic foot analysis
composite materials
konstrukcja stopy protetycznej
włókno kenaf
analiza stopy dynamiczna
materiały kompozytowe
Opis:
Purpose: To design and manufacture a dynamic cheap prosthetic foot compatible with amputees' requirements by introducing a natural fibre called kenaf (scientific name Hibiscus cannabinus L). Design/methodology/approach: In two cases, four suggested designs were analysed using the finite elements method (FEM) with a commercial ANSYS R1 program. The first case was a heel strike. The second was toe-off by subjecting force equal to 70 kg for both cases to select the optimal design. Findings: The foot found the tensile strength, flexural strength, impact stress, and fatigue test according to ISO 10328 standards successfully. Research limitations/implications: The selected design was analysed again using the ANSYS R1 program for weights 60, 70, and 80 kg for two sequences, one containing kenaf, to study how such additive could affect the mechanical properties and estimate the proper quality weight of the foot. The winner's design was then produced and tested in a fatigue foot tester according to ISO 10328 standards. Practical implications: The results showed that the sequence containing the natural fibres kanaf material improved the deformation by 20% for both cases (from 7.47 to 8.92 mm for the heel strike case for a weight of 80 kg for the sequence without and with kanaf, respectively), and the damping ratio increased by 50% (0. 188 and 0.273 for the sequence without and with kenaf, respectively), which means an increase in the stored energy and higher stability. Also, the mechanical properties like maximum tensile strength, flexural strength, impact stress, and natural frequency were modified. Originality/value: This paper develops an analytical and practical study to design and produce a dynamic cheap prosthetic foot made from natural fibres, which are characterized as renewable, cheap, recyclable, and environmentally friendly materials with good mechanical properties. Authors believe it is the first time to use natural kenaf fibres in the prosthetic foot manufacturing field.
Źródło:
Archives of Materials Science and Engineering; 2022, 115, 1; 21--33
1897-2764
Pojawia się w:
Archives of Materials Science and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The foot deformity versus postural control in females aged over 65 years
Autorzy:
Drzal-Grabiec, J.
Rachwał, M.
Trzaskoma, Z.
Rykała, J.
Podgórska, I.
Cichocka, I.
Truszczyńska, A.
Rąpała, K.
Powiązania:
https://bibliotekanauki.pl/articles/306586.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stabilność
deformacja
stopa
kobieta
monitoring
postural stability
aging
foot deformity
females
Opis:
Purpose: Correct foot structure is important due to locomotion and postural stability. The aim of this study was to determine the relationships between morphological foot structure and balance indices in a quiet standing position in women over 65 years of age. Methods: The study included 116 women aged 65-90 years. The mean age was 70.6±8.4 years and BMI 29.1±3.4 m/kg2. The measured indices included postural control while standing on both feet and photogrammetric foot evaluation. An analysis was performed of the selected foot and balance indices. Results: There were no significant differences observed in the feet structure. Certain correlations between some foot indices and the indices of postural control were noted. The increased differences in the width indices between the right and the left foot lead to balance deterioration. Larger angles of valgity and varus deformity of toes and indices describing the longitudinal arch and transverse front arch of the foot have the greatest impact on the deterioration of balance in the medio-lateral axis. Conclusions: The differences between the indices and morphological indices for the right and the left foot are not significant, which indicates the proportionate formation of feet in the individual life. The increased differences in the width indices between the right and the left foot lead to balance deterioration. Larger angles of valgity and varus deformity of toes and indices describing the longitudinal arch and transverse front arch of the foot have the greatest impact on the deterioration of balance in the medio-lateral axis.
Źródło:
Acta of Bioengineering and Biomechanics; 2014, 16, 4; 75-82
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A real time plantar pressure feedback device for foot unloading
Autorzy:
Femery, V.
Hespel, J.M.
Thevenon, A.
Moretto, P.
Powiązania:
https://bibliotekanauki.pl/articles/333989.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
chód
ciśnienie podeszwowe
obciążenia stopy
powiększone czuciowe reakcje
gait
plantar pressure
foot unloading
motor control
augmented sensory feedback
Opis:
The design and development of a plantar pressure control device, adapted to correct plantar pressure distribution patterns, is described. This device is based on the artificial return of information in real time to instantaneously reveal to subject certain events, of which he was unaware and which are difficult to quantify, such as the pressure variation generated by foot-ground contact. An acoustic alarm and visual signals, adjusted to a specific pressure load, alert the user in the case of excessive plantar pressure. So, our feedback device is designed to substitute for loss of feeling in patients who have peripheral neuropathy secondary to diabetes mellitus. The ultimate aim of this project is to prevent the development of neuropathic foot ulceration by providing both visual and auditory extrinsic sensory feedback to compensate for the malfunctioning peripheral nerves and to transmit information to the patient about dangerous conditions on the plantar surface of the feet. A trial of the device in a healthy subject is presented to evaluate whether a new gait pattern can emerge thanks to feedback from plantar pressure measurements.
Źródło:
Journal of Medical Informatics & Technologies; 2003, 6; IT103-106
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
How foot morphology changes influence shoe comfort and plantar pressure before and after long distance running?
Autorzy:
Mey, Q.
Gu, Y.
Sun, D.
Fernandez, J.
Powiązania:
https://bibliotekanauki.pl/articles/306388.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
ciśnienie podeszwowe
obuwie
kształt stopy
komfort
bieg długodynstansowy
foot shape
plantar pressure
footwear
comfort
long distance running
Opis:
Prolonged running has been popularized globally in recent decades. This study was aimed to reveal information about foot morphology, shoe comfort and plantar loading among recreational heel-strike runners. Methods: Twenty-six runners participated in foot morphology, perceived scores and peak pressure tests after 10- and 20-km track running. The foot morphology was measured using a 3D foot scanner, perceived scores were recorded using a visual analogue scale and plantar pressure was measured via insole plantar pressure measurement system. The statistical significance level was set at 0.05. Results: The heel midsole materials properties were measured before and after 20 km. Significant changes were observed in ball width and girth, arch height and foot volume. The perceived scores showed significance in overall, forefoot and heel comfort, arch support and forefoot width. Peak pressure to the heel, medial mid-foot and metatarsal greatly increased. The first metatarsal showed consecutive increase from static to 10 km, and 20 km, while big-toe showed a decrease. Conclusions: The morphology variations and forefoot loading concentration may lead to discomfort and possibly imply dermatological problems and metatarsal bone stress, particularly on the first metatarsal. Combining changes of heel midsole property, knowledge of foot shape, shoe perception and plantar pressure is of great value for recreational long-distance running shoes design and materials selection.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 2; 179-186
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Enhanced evaporation of the condensate droplets within the asymmetrical shock wave zone
Autorzy:
Kornet, S.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175164.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
revaporization
shock wave
homogenous condensation
asymmetrical lambda foot
Opis:
The present work is concerned with investigation into coupled phenomena occurring in the supersonic section of the de Laval nozzle, characterized by the presence of shock the flow of condensing steam. The numerical simulations results were compared with the experiment carried out by Dykas et al. in 2013 on the half arc nozzles. The present work includes simulations results of oscillation frequency of the shock wave and conditions for the enhancement evaporation of condensate within the asymmetrical shock wave. Novelty of our approach lies on modeling both the moment of initiation of a phase transition, as well as the moment of its reverse progress – called here revaporization of the condensate phase.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 119-130
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertebrate tracks in Late Pleistocene–Early Holocene (?) carbonate aeolianites, Paphos, Cyprus
Autorzy:
Milàn, J.
Theodorou, G.
Loope, D. B.
Panayides, J.
Clemmensen, L. B.
Gkioni, B.
Powiązania:
https://bibliotekanauki.pl/articles/191876.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
Cyprus
aeolian
foot prints
probocideans
hippopotamus
insular dwarfism
track preservation
Opis:
In 2005, numerous vertebrate tracks were discovered in carbonate aeolianites in and around the town of Paphos, in the south western part of Cyprus. The main track-bearing exposure is located in a protected archaeological site near the Agia Solomoni Church in side the city of Paphos, where cross-sec tions through tracks are abundant in vertical exposures of the aeolianite along Apostolou Pavlou Avenue. Some exposures show as many as 10 tracks per m2 of vertical exposure. Several additional tracks were found in the extensive subterranean tomb complex, the Tombs of the Kings, just outside Paphos. The aeolian deposit was formed when westerly to southwesterly windsdrove fine- to medium-grained calcareous sand onshore from the beach. This generated low coastal dunes, represented by 1–2-m-thick, cross-bedded sets made up of grainflow and wind-ripple strata, and sand sheets composed entirely of wind-ripple strata. The sediment does not yet have an absolute date, but is considered to be of Late Pleistocene to Early Holocene age, as are many other coastal aeolianites in the Mediterranean area. The Late Pleistocene endemic fauna in Cyprus was limited to the dwarf hippopotamus Phanourios minor Desmarest, 1822, the dwarf elephant Elephas cypriotes Bate, 1902, a small carnivore Genetta plesictoides Bate, 1903, and (possibly) humans. The exposed tracks are 5–15 cm in diameter, with a few tracks up to 23 cm in size. This range of size correlates well with the estimated foot size of dwarf hippopotami and dwarf elephants. This low-diversity, endemic is land fauna provides a unique opportunity to correlate tracks with trackmakers.
Źródło:
Annales Societatis Geologorum Poloniae; 2015, 85, 3; 507-514
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of different dietary sodium levels on blood electrolytes, growth performance and foot pad dermatitis incidence in turkeys
Wpływ zróżnicowanego poziomu sodu w diecie na poziom elektrolitów krwi, wzrost indyków i występowanie zapalenia skóry poduszki stopy
Autorzy:
Lichtorowicz, K.
Jankowski, J.
Zdunczyk, Z.
Juskiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/14741.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Opis:
The objective of this study was to determine the effect of different dietary sodium levels on serum macroelement concentrations, growth performance and incidence of foot pad dermatitis (FPD) in female turkeys raised to six weeks of age. The influence of a lowsodium diet (without additional sodium) and diets supplemented with NaCl to increase sodium content by 0.5, 1.0, 1.5, 2.0 and 2.5 g kg–1 was compared. The dietary electrolyte balance (DEB) was high (242-248 mEq kg–1) due to a high potassium content (11.0 g kg–1). Turkeys fed the low-sodium diet were characterized by significantly lower concentrations of chloride (p=0.002) and phosphorus (p<0.001), and significantly higher magnesium levels (p<0.001), compared with the other groups. The lowest dietary inclusion of sodium (0.5 g kg–1) contributed to a significant increase in the body weights of turkeys at six weeks of age (p<0.001), and it improved feed conversion efficiency (p<0.001) in comparison with the low-sodium diet. No significant differences in body weight and feed conversion ratio followed experimental treatments with higher dietary NaCl addition. Diets supplemented with different amounts of sodium had no effect on litter moisture content, whereas the incidence of FPD increased significantly following the addition of dietary sodium at 1.0 g kg–1 to 2.5 g kg–1, compared with the low-sodium diet. The results of our study indicate that moderate sodium supplementation (0.5 g kg–1) of a sodium-deficient diet significantly increased the body weights of young turkeys, while it did not increase the incidence of FPD. A further increase in the sodium content of experimental diets did not increase the body weights of birds, and it enhanced the occurrence of FPD which was not related to increased litter wetness.
Celem badań było określenie wpływu różnych poziomów sodu w diecie na zawartość makrolementów w surowicy, wzrost ptaków i występowanie zapalenia skóry stóp (FPD) u indyczek w wieku sześciu tygodni życia. Porównano efekty podawania diety niskosodowej (bez dodatkowego źródła sodu) i diet z dodatkiem NaCl w ilości 0,5; 1,0; 1,5; 2.0 i 2,5 g kg–1. Ze względu na wysoką zawartość potasu w dietach (11,0 g kg–1), bilans elektrolitów (DEB) był również wysoki (242-248 mEq kg–1). U indyków żywionych dietą o niskiej zawartości sodu wykazano znacznie niższy poziom chlorku (p=0,002) i fosforu (p<0,001), a znacznie wyższy poziom magnezu (p<0,001) w surowicy krwi, w porównaniu z innymi grupami. Niewielkie zwiększenie zawartości Na w diecie (0,5 g kg–1) spowodowało istotny wzrost masy ciała indyków w wieku sześciu tygodni (p<0,001) i poprawę wykorzystania paszy (p<0,001), w porównaniu z diet¹ bez dodatku Na. Nie stwierdzono istotnych różnic w masie ciała i wykorzystaniu paszy u indyków otrzymujących diety z dodatkiem NaCl. Dodatek NaCl do diety nie wpłynął na wilgotność ściółki, natomiast występowanie FPD istotnie nasiliło się w grupach otrzymujących dodatek 1,0 i 2,5 g kg–1 Na, w porównaniu z dietą bez dodatku sodu. Stwierdzono, że umiarkowany dodatek sodu (0,5 g kg–1) do diety ubogiej w ten pierwiastek istotnie zwiększa masę ciała młodych indyków, a nie zwiększa częstości występowania FPD. Dalszy wzrost zawartości sodu w diecie nie zwiększa masy ciała ptaków i wilgotności ściółki, a nasila występowanie FPD.
Źródło:
Journal of Elementology; 2012, 17, 2
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research of the spatial-temporal gait parameters and pressure characteristic in spastic diplegia children
Autorzy:
Pauk, J.
Ihnatouski, M.
Daunoraviciene, K.
Laskhousky, U.
Griskevicius, J.
Powiązania:
https://bibliotekanauki.pl/articles/306432.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
porażenie obustronne
stopa
chód
orteza
rozkład ciśnień
spastic diplegia
spatial-temporal parameters
gait
pressure distribution
ankle-foot orthosis
Opis:
Purpose: Spastic diplegia is the most common form of cerebral palsy. It presents with symmetric involvement of the lower limbs and upper limbs. Children with spastic diplegia frequently experience problems with motor control, spasticity, and balance which lead to gait abnormalities. The aim of this study is twofold. Firstly, to determine the differences in spatial-temporal gait parameters and magnitude of plantar pressure distribution between children with spastic diplegia (CP) and typical children. Secondly, to compare and evaluate main changes of plantar pressure and spatial-temporal gait parameters instead of data between spastic diplegia children with prescribed ankle – solid foot orthosis (AFOs) and without using AFOs. Methods: The evaluation was carried out on 20 spastic diplegia children and 10 agematched children as a control group aged 6–15 years. Twenty children with spastic diplegia CP were divided into two groups: ten subjects with prescribed AFOs and ten subjects without use of assistive device. Patients used the AFOs orthosis for one year. Measurements included in-shoe plantar pressure distribution and spatial-temporal gait parameters. Results: Spatial-temporal gait parameters showed meaningful difference between study groups in velocity, stride length, step length and cadence ( p < 0.05). However no significant differences between patients with and without AFOs were found ( p > 0.05). Significant differences between typical and spastic diplegia children with AFOs were observed in the magnitude of plantar pressure under the toes, the metatarsal heads, the medial arch, and the heel ( p < 0.05). For typical subjects, the highest pressure amplitudes were found under the heel and the metatarsal heads, while the lowest pressure distribution was under the medial arch. In CP patients the lateral arch was strongly unloaded. The peak pressure under heel was shifted inside. Conclusions: Collected data and calculated scores present a state of the gait in test groups, showed the difference and could be valuable for physicians in decision making by choosing qualitative therapy. Furthermore, it allows predicting probability of further possible changes in gait of spastic diplegia patients with AFOs and without it. In conclusion, our current results showed that the use of AFOs, prescribed on a clinical basis by doctors improves gait patterns and gait stability in children with spastic cerebral palsy.
Źródło:
Acta of Bioengineering and Biomechanics; 2016, 18, 2; 121-129
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hands, feet, and behaviour in Pinacosaurus (Dinosauria: Ankylosauridae)
Autorzy:
Currie, P.J.
Badamgarav, D.
Koppelhus, E.B.
Sissons, R.
Vickaryous, M.K.
Powiązania:
https://bibliotekanauki.pl/articles/21347.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
hand
foot
animal behaviour
Pinacosaurus
Dinosauria
Ankylosauridae
Cretaceous
Alag Teeg
Mongolia
Pinacosaurus grangeri
dinosaur
Pinacosaurus ninghsiensis
Opis:
Structure of the manus and pes has long been a source of confusion in ankylosaurs, owing to the imperfect preservation or complete lack of these parts of the skeletons in most specimens, and the fact that many species appear to have undergone a reduction in numbers of digits and phalanges. New specimens of Pinacosaurusfrom Alag Teeg in Mongolia confirm that the phalangeal formula of the manus is 2−3−3−3−2. However, there are only three toes in the pes, which has a phalangeal formula of X−3−3/4−3/4−X. Importantly, the number of phalanges in the third and fourth pedal digits can vary between either three or four per digit, even within the same specimen. The Alag Teeg site has yielded as many as a hundred skeletons of the ankylosaur Pinacosaurus, most of which were immature when they died. Each skeleton is preserved in an upright standing position, with the bones of the lower limbs often in articulation. The remainder of the skeleton, including the upper parts of the limbs, is generally disarticulated and somewhat scattered. Based on the presence of large numbers of juvenile Pinacosaurus specimens at Alag Teeg, as well as other Djadokhta−age sites (Ukhaa Tolgod in Mongolia, Bayan Mandahu in China), it seems juvenile Pinacosaurus were probably gregarious.
Źródło:
Acta Palaeontologica Polonica; 2011, 56, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Postcranial remains of basal typotherian notoungulates from the Eocene of northwestern Argentina
Autorzy:
Armella, M.A.
Garcia-Lopez, D.A.
Babot, M.J.
Deraco, V.
Herrera, C.M.
Saade, L.
Bertelli, S.
Powiązania:
https://bibliotekanauki.pl/articles/2082173.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Mammalia
Notoungulata
calcaneum
astragalus
plantigrade
foot stances
Paleogene
South America
Opis:
Notoungulates represent the most taxonomically diverse and temporally and geographically widespread group among South American native ungulates. Here, we analyze anatomical and systematic aspects of proximal tarsal bones recovered from the Lower and Upper Lumbrera formations (middle and late middle Eocene) in northwestern Argentina. We provide detailed descriptions, comparisons, and infer foot stances and range of movements for the taxa implicated. Material studied includes astragali belonging to the oldfieldthomasiid Colbertia lumbrerense (Lower Lumbrera Formation), a set of proximal tarsals referred as Typotheria indet. (Lower Lumbrera Formation), and tarsals (also including navicular and cuboid) of the informal taxon “Campanorco inauguralis” (Upper Lumbrera Formation). The comparison of the tarsals of Colbertia lumbrerense (middle Eocene of Argentina) with Colbertia magellanica (early Eocene of Brazil) reveals several differences including variations on the development and arrangement of articular facets, and the size of the dorsal astragalar foramen in the Argentinean species. The specimen of Typotheria indet. shows morphological affinities with basal interatheriid taxa. However, its larger size contrasting with the overall small body sizes of Eocene interatheriids precludes an indisputable taxonomic assignment. Concerning “Campanorco inauguralis”, our observations indicate that there is no morphological evidence for a close phylogenetic relationship with Mesotheriidae. It presents a “reversed alternating tarsus” condition, which is also observed in Leontiniidae, “Notohippidae”, Toxodontidae, and some typotherians. However, the spectrum of singularities exhibited by this form precludes the assessment of its relationships in the context of the Paleogene radiation of Typotheria and it is necessary to extend the comparison to Eocene notoungulates. Finally, in a morphofunctional context a plantigrade foot posture is inferred for the specimens here reported. These observations have the potential to provide functional proxies for paleoecological reconstructions to be applied to the study of the early radiation of these notoungulate faunas.
Źródło:
Acta Palaeontologica Polonica; 2020, 65, 2; 1-17
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probability of the Critical Length of a Fatigue Crack Occurring at the Tooth Foot of Cylindrical Geared Wheels of the Drive System of a Fiomax 2000 Ring Spinner
Probabilistyczne prognozowanie krytycznej długości pęknięcia przy podstawie zęba koła walcowego układu napędowego przędzarki obrączkowej Fiomax 2000
Autorzy:
Rysiński, J.
Drobina, R.
Tomaszewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/232136.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
tooth foot crack
Paris-Erdogan formula
probability distribution
cycle number
crack critical length
evaluation
fatigue life
cracked tooth
ring spinner
ring spinning frame
koło układu napędowego
wzór Parisa-Erdogan
krytyczna długość pęknięcia
ewaluacja
odporność na zmęczenie
pierścień przędzenia
Opis:
In the present paper, we describe a method of determination of the probability of reaching the critical crack length at the tooth root of the cylindrical geared wheels of the drive system of the Fiomax 2000 ring spinner. The Paris-Erdogan formula was utilised for calculations of the fatigue crack length depending on the number of load cycles. Experimental investigations were performed on cylindrical geared wheels. The wheel specimens were manufactured from 1.6523 steel (UE) according to a technical specification relevant to the drive system of the ring spinner. The experiments were performed using a professional pulsator (pulsating test machine). Based upon the experiments (series of 12 tests), material constants and were calculated. These parameters were utilised in the Paris law of crack propagation for further calculations. Moreover it was also ascertained that these unknowns are related via the deterministic relationship. Therefore a function allowing for approximation of constant in dependence on exponent m was derived. In the next step, for the values of parameter chosen – belonging to the variability interval, established from experimental data – we determined the times of reaching the critical length of the fatigue crack. It was stated that the best approximation distribution describing the simulated random values of times of reaching the critical length of the tooth crack for the drive system of the ring spinner is the asymptotic Gumbel’s distribution. Knowing the distribution and number of cycles until reaching the critical crack length at the tooth root, one can evaluate the fatigue life of the damaged wheel in the ring spinner (Fiomax) drive system for the assumed probability. The goal of the present paper is evaluation of the working time of the elements of the drive system of a ring spinner until the occurrence of damage. The highest fatigue life of geared wheels was achieved within the interval (4.3 – 4.5)x 105 cycles. However, it is recommended to change of the geared wheel in case of the spotting of early symptoms of defect. For the stretching apparatus, the authors of the present paper suggest the exchange of the idler geared wheels at least once per year.
W pracy opisano metodę wyznaczenia prawdopodobieństwa osiągnięcia krytycznej długości pęknięcia przy podstawie zęba koła walcowego układu napędowego przędzarki obrączkowej Fiomax 2000. Do wyznaczenia zależności długości pęknięcia zmęczeniowego od liczby cykli zastosowano wzór Parisa-Erdogano. Badaniom doświadczalnym poddano koła walcowe o geometrii zgodnej z kołami zastosowanymi w układzie napędowym przędzarki obrączkowej, wykonane ze stali 1.6523 (UE), poddane obciążeniu na pulsatorze. Dla każdej z 12 prób wyznaczono stałe materiałowe C i m dla prawa propagacji pęknięć wg Parisa i stwierdzono, że istnieje pomiędzy nimi zależność deterministyczna. Wyznaczono funkcję aproksymującą stałą C od wykładnika m. Następnie dla wybranych wartości m z przedziału zmienności, wyznaczonego z danych empirycznych, wyznaczono czasy osiągnięcia krytycznej długości pęknięcia zmęczeniowego. Stwierdzono, że najlepszym rozkładem aproksymującym symulowane losowe wartości czasu osiągnięcia krytycznej długości pęknięcia zęba w układzie napędowym przędzarki jest rozkład asymptotyczny Gumbela. Znając rozkład liczby cykli do osiągnięcia krytycznej długości pęknięcia podstawy zęba można prognozować trwałość uszkodzonego koła układu napędowego przędzarki Fiomax z zadanym prawdopodobieństwem.
Źródło:
Fibres & Textiles in Eastern Europe; 2017, 1 (121); 134-144
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Geomorphological conditions of water-air properties in the silt soils from the edge zone of the Carpathian Foothills
Autorzy:
Klimek, M
Zaleski, T.
Niemyska-Lukaszuk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1401888.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
Carpathian foot-hills
retention
air property
geomorphology
soil
relief
water property
condition
porosity
silt soil
Opis:
In this paper an attempt to estimate the influence of the relief on the selected physical soil properties from the edge zone of the Carpathian Foothills has been presented.Differentiation of water-air properties related to the location on the slope was evaluated.It results from, both, the main soil forming process-lessivage, erosion and accumulative changes in the morphology of the soil profile.Soils lessives situated on tops and slopes less prone to erosion are characterised by deeper eluvial horizons - luvic with a higher total porosity and water retention in comparison to illuvial horizons - argillic. Eroded lessivé soils occur on the slopes prone to erosion with the argillic horizon outeropped to the surface which determins their properties in the whole soil profile, first of all, their porosity is low and they have a limited capacity for water retention. Gley soils occur in the valley bottoms and synclines of slopes. They arc characterised by higher total porosity and retention in the whole profile in comparison to the lessivé soils.
Źródło:
Acta Agrophysica; 2000, 35; 93-98
1234-4125
Pojawia się w:
Acta Agrophysica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary Evaluation of Airlaid Nonwovens with Superabsorbent for Use in Protective Footwear: Tests Involving a Thermal Foot Model and Climatic Chamber
Ocena właściwości chłonnych wkładek obuwiowych ze specjalnych włóknin z użyciem komory klimatyzacyjnej oraz modelu termicznego stopy
Autorzy:
Irzmańska, E.
Dutkiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/232825.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
nonwovens
superabsorbents
protective footwear
insoles
włókniny
właściwości chłonne
obuwie ochronne
wkładki obuwiowe
Opis:
The paper presents preliminary results of simulation studies evaluating moisture absorption from the air that indicate the possibility of applying a superabsorbent polymer (SAP) in the construction of protective footwear insoles. The performance of different types of nonwovens was tested in terms of moisture absorption from air of high relative humidity in a climatic chamber and on a thermal foot model. The tests simulated the temperature and humidity conditions that occur inside all-rubber protective footwear. It was found that insoles containing SAP dehumidified the air more effectively than either insoles not containing SAP or traditional wool felt insoles. The tests showed a new application potential of absorbent materials in protective footwear with a view to improving hygienic comfort during use.
Artykuł prezentuje wstępne wyniki badań modelowych związanych z oceną sorpcji wilgoci z powietrza i wskazujących na możliwość zastosowania superabsorpcyjnego polimeru (SAP) w konstrukcji wkładek do obuwia ochronnego. Ocenę wydajności włóknin, pod względem pochłaniania wilgoci z powietrza o dużym nasyceniu parą wodną, przeprowadzono w laboratorium w komorze klimatyzacyjnej oraz z użyciem termicznego modelu stopy. Podczas badania wkładek zamodelowano warunki temperaturowo-wilgotnościowe jakie panują wewnątrz użytkowanego obuwia ochronnego całkowicie wykonanego z gumy. Zaobserwowano, że wkładki zawierające SAP, powodowały osuszanie powietrza (spadek wilgotności względnej wewnątrz obuwia ochronnego wykonanego z gumy) w porównaniu do wkładek niezawierających SAP oraz tradycyjnie stosowanego filcu wełnianego. Badania wskazują nowy kierunek aplikacji materiałów chłonnych w obuwiu ochronnym nóg do poprawy komfortu higienicznego podczas ich użytkowania.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 6 (114); 138-142
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 17

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