bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical Behaviour of Type 316L Austenitic Stainless Steel in Low Pressure Hydrogen Steam Environment
Authors: Janoušek J 
Published: September 2021

Abstract
Low pressure superheated H2-steam appears to be an interesting alternative to pressurized water environments, since it is capable of performing accelerated environmentally assisted cracking (EAC) experiments for nickel base and stainless steel alloys. Constant Extension Rate Tensile (CERT) tests were performed with strain rates of 2 × 10−6 or 2 × 10−8 ms−1 at 350, 400, 440 and 480 °C on flat tapered specimens of Type 316L austenitic stainless steel. The tapered shape allows the determination of crack initiation over a range of stresses and strains simultaneously on one specimen and therefore the threshold stress value was obtained. The environment was 6 times more oxidizing than the dissociation pressure of NiO. The acquired mechanical properties are summarized and threshold stresses for EAC crack initiation are evaluated.
Design & Modelling of Double Cantilever structure by Stainless Steel 316L deposited using Additive Manufacturing Directed Energy Deposition Process
Authors: Kiran A , Hodek J , Vavřík J , Brázda M , Urbánek M , Cejpek J 
Published: September 2021

Abstract
Distortion in the metal additive manufacturing due to inherent residual stress during the separation of the deposited part from the base plate is critical. Distortion gets amplified after removing it from the build platform. Internal stress in the deposited sample during the material deposition and cooling phase is crucial to estimate. Residual stress in the structure influences structural distortion. Numerical analysis of residual stress prior to deposition helps to identify inconsistent stress in the built part and helps to take required measures like optimising process parameters, base plate preheat to make it less significant. Residual stress estimation before deposition using numerical calculation plays a major role in the improvement of the built part and establishing technology for a wide application. A numerical model for thermal history and residual stress estimation has been developed for Directed Energy Deposition (DED). A standard double cantilever model was considered for physical deposition and numerical model verification. Thermal history from Finite Element (FE) Analysis was compared with the in-situ measurement. A close agreement was noticed between in situ measurement and simulation results. A double cantilever was built using austenite stainless steel 316L by the DED technique. Internal stress in the deposited part before and after a partial separation from the base plate was compared. Numerical results comparison before and after separation emphasize the impact of residual stress on distortion.
New approach to heat treatment of spring steel
Authors: Kotous J , Salvetr P , Procházka R 
Published: September 2021

Abstract
In the 54SiCr6 spring steel, a spheroidized structure was achieved by two processing methods: conventional soft annealing above the temperature A1 in a furnace and accelerated ASR annealing by an induction heating equipment. The ASR technology is much faster, even for materials with a worse tendency to the spheroidisation, such as steels with higher silicon content. Thanks to this, a finer structure is obtained. This is the basis of other advantages for the subsequent hardening. Quenching can be done at lower temperatures, higher yield and tensile strength is obtained while maintaining same or improved ductility and contraction. This also results in influencing of fatigue behavior.
Influence of surface structures on wettability
Authors: Kvitek L , Saran D , Vaclavek L , Kapusta J , Kozmin P 
Published: September 2021

Abstract
Wettability of solid surfaces is a key parameter for many industrial applications of solid materials. The wettability is influenced not only by the nature of the material but also by the existence of surface structures. Crucial influence of the oriented surface structures on the shape of liquid drop was observed in this study. Observed differences in value of contact angle measured on the metal surface at two perpendicular directions were 19° for water and 23° for diiodomethane. These surface structures can significantly influence liquid and heat transfer on structured surfaces.
Theoretical study of the process of balls rolling with a diameter of 40 mm on a ball rolling mill
Authors: Naizabekov A , Mukhametkaliyev B , Lezhnev S , Panin E 
Published: September 2021

Abstract
The following calibration scheme for rolling round steel is used for producing thermally hardened grinding balls with a diameter of 40 mm at JSC SSGPO for 320 variety rolling mill: a round billet with a diameter of 40 mm is produced from the initial billet of 120 × 120 mm. In the last developed scheme the square billet 150x150 mm is used as an initial billet for whole mill where the round steel with diameter of 40 mm is obtained from the above mentioned billet and then this round steel is used for production of balls with a diameter of 40 mm. Computer simulation of the ball rolling process in the Simufact Forming program was performed. The results of strain state distribution showed that the maximum processing level in the surface layers of balls is observed, while the stress state distribution showed that in the surface layers prevail high compressive stresses up to −400 MPa. Such stress-strain state leads to formation of gradient structure in the ball cross-section, where the surface layers will have more high mechanical properties. That is the most optimal result for details worked in condition of high values of friction.
Characterization of Microstructure Variations by Laser-Ultrasound during and after the Heat Treatment of Metals
Authors: Scherleitner E , Kerschbaummayr C , Haderer W , Reitinger B , Mitter T , Gruensteidl C 
Published: September 2021

Abstract
We demonstrate the potential of laser ultrasound for non-destructive testing applications in steel production and processing in two use cases: (1) Imaging of the grain structure transition between the thermally hardened surface and the unaffected core material with a comparison to sectional views by an optical microscope. We found very good correlation between the laser ultrasonic image and the microscopic view at the cross section. (2) In situ monitoring of Poisson’s ratio of steel sheets during thermal processes by evaluation of resonant frequencies of Lamb waves. In our ongoing research the results will be correlated to metallurgical properties of interest.
Influence of micro- and nanoparticles on mechanical properties of magnesium and magnesium alloys
Authors: Trojanová Z , Lukáč P , Džugan J 
Published: September 2021

Abstract
Magnesium and magnesium alloys were reinforced with various micro- and nanoparticles (SiC, Inconel718, AI2O3, ZrC2, BN, graphite) Composites were prepared by squeeze casting and using powder metallurgy followed by hot extrusion. Tensile and compression tests were performed at elevated temperatures up to 300 °C. The influence of micro- and nanoparticles on mechanical characteristics is discussed on the base of physical models. Bonding at the interface between particles and magnesium matrix plays an important role for the resulting composite properties.
Determination of Fracture Limit Line in Principal Strain Space by Shear Tests
Authors: Urbánek M. , Fedorko M. , Rund M. 
Published: September 2021

Abstract
The main goal of this paper was to define a new limit line, which expands Forming Limit Curve (FLC) more precisely Fracture Forming Limit Curve (FFLC). The new limit line was defined by damage models transformed from triaxiality-fracture strain space to the major/minor strain space and we focused on the shear area. Because FLC and FFLC have some limitations, for example, some Advanced High Strength Steels (AHSS) fractures before thinning. Another limitation can be seen on the left side of the diagrams in the shear region, where the part can break in the process without crossing the FLC or FFLC. The different shapes of samples were used for finding a new line of the FFLC and Deep Drawing Test (DDT) was used for verification. The fracture points from measurement were used for calibration of simple uncoupled damage models. The simple model means model, which is calibrated based on one or two measurements (tensile test or tensile test + shear test). This paper was used an Advanced High Strength Steel (AHSS) DP1000 sheet with a thickness of 0.8 mm for the experiments.
Possibilities of using thermally sprayed coatings for surface treatment of rail vehicles components
Authors: Vostřák M , Brodský J , Houdková Š , Šulcová P 
Published: September 2021

Abstract
Thanks to their versatile properties and economical applicability, thermally sprayed coatings are being used in more and more areas of industry. Within the research project, suitable alternatives are being sought for the replacement of surface treatments of selected components of rail vehicles with thermal spraying. The aim is to increase the functionality and service life of selected parts and thus the entire vehicle. Based on the requirements for the functional properties of components, variants for the material and technology of thermal spraying are selected. Technologies considered include HVOF, TWAS, FS, and APS, materials include Fe, Ni, Zn, and Mo based alloys; WC and CrC based cermets. The basic functional properties of these coatings are analyzed and discussed. The further steps of the work to test suitability of these coatings for selected applications and are outlined.
Corrosion behaviour of hydroxyapatite (HAP) coated AISI 316Ti austenitic biomaterial
Authors: Zatkalíková V , Markovičová L , Uhríčik M , Hanusová P 
Published: September 2021

Abstract
HAP bioactive coatings are widely applied to improve the bone response in orthopedic and dental stainless steels implants. Mechanical properties of the metallic implant are preserved and moreover, HAP improves the corrosion resistance. This article deals with the corrosion resistance of AISI 316Ti austenitic biomaterial with electrochemically deposited HAP coating. Corrosion behaviour is evaluated on the bases of two independent methods-the electrochemical potentiodynamic polarization test and exposure immersion tests, both carried out in physiological solution (0.9 % NaCl) at the temperature 37 ± 0.5 °C. The microstructure and chemical composition of HAP coating is evaluated by SEM and EDX analysis. According to the results of the potentiodynamic test, the HAP coated biomaterial shows the considerably higher corrosion resistance compared to that without the HAP coating. However, the corrosion losses and SEM analysis after the exposure test revealed severe disruption of the HAP coating and the stainless steel substrate started to corrode.
On the existence of foliations by solutions to the exterior Dirichlet problem for the minimal surface equation
Authors: Aiolfi Ari , Bustos Daniel , Ripoll Jaime 
Published: September 2021

Given an exterior domainΩ\OmegawithC2,αC^{2,\alpha }boundary inRn\mathbb {R}^{n},n≥3n\geq 3, we obtain a11-parameter familyuγ∈C∞(Ω)u_{\gamma }\in C^{\infty }\left ( \Omega \right ),|γ|≤π/2\left \vert \gamma \right \vert \leq \pi /2, of solutions of the minimal surface equation such that, if|γ|>π/2\left \vert \gamma \right \vert >\pi /2,uγ∈C∞(Ω)∩C2,α(Ω¯)u_{\gamma }\in C^{\infty }\left ( \Omega \right ) \cap C^{2,\alpha }\left ( \overline {\Omega }\right ),uγ|∂Ω=0u_{\gamma }|_{\partial \Omega }=0withmax∂Ω‖∇uγ‖=tan⁡γ\max _{\partial \Omega }\left \Vert \nabla u_{\gamma }\right \Vert =\tan \gammaand, if|γ|=π/2\left \vert \gamma \right \vert =\pi /2, the graph ofuγu_{\gamma }is contained in aC1,1C^{1,1}manifoldMγ⊂Ω¯×RM_{\gamma }\subset \overline {\Omega }\times \mathbb {R}with∂Mγ=∂Ω\partial M_{\gamma }=\partial \Omega. Each of these functions is bounded and asymptotic to a constant\[cγ=lim‖x‖→∞uγ(x).c_{\gamma }=\lim _{\left \Vert x\right \Vert \rightarrow \infty }u_{\gamma }\left ( x\right ) .\]The mappingsγ→uγ(x)\gamma \rightarrow u_{\gamma }\left ( x\right )(for fixedx∈Ωx\in \Omega) andγ→cγ\gamma \rightarrow c_{\gamma }are strictly increasing and bounded. The graphs of these functions foliate the open subset ofRn+1\mathbb {R}^{n+1}\[{(x,z)∈Ω×R, −uπ/2(x)>z>uπ/2(x)}.\left \{ \left ( x,z\right ) \in \Omega \times \mathbb {R}\text {, }-u_{\pi /2}\left ( x\right ) >z>u_{\pi /2}\left ( x\right ) \right \} .\]Moreover, ifRn∖Ω\mathbb {R}^{n}\backslash \Omegasatisfies the interior sphere condition of maximal radiusρ\rhoand if∂Ω\partial \Omegais contained in a ball of minimal radiusϱ\varrho, then\[[0,σnρ]⊂[0,cπ/2]⊂[0,σnϱ],\left [ 0,\sigma _{n}\rho \right ] \subset \left [ 0,c_{\pi /2}\right ] \subset \left [ 0,\sigma _{n}\varrho \right ] ,\]where\[σn=∫1∞dtt2(n−1)−1.\sigma _{n}=\int _{1}^{\infty }\frac {dt}{\sqrt {t^{2\left ( n-1\right ) }-1}}.\]One of the above inclusions is an equality if and only ifρ=ϱ\rho =\varrho,Ω\Omegais the exterior of a ball of radiusρ\rhoand the solutions are radial.

These foliations were studied by E. Kuwert in [Ann. Inst. H. Poincaré Anal. Non Linéaire 10 (1993), pp. 445–451] and our result answers a natural question about the existence of such foliations which was not touched by Kuwert.
In Search of an Honest Butterfly: Sexually Selected Wing Coloration and Reproductive Traits From Wild Populations of the Cabbage White Butterfly
Authors: Espeset Anne E , Forister Matthew L 
Published: September 2021

Abstract
Sexual selection is central to many theories on mate selection and individual behavior. Relatively little is known, however, about the impacts that human-induced rapid environmental change are having on secondary sexually selected characteristics. Honest signals function as an indicator of mate quality when there are differences in nutrient acquisition and are thus potentially sensitive to anthropogenically altered nutrient inputs. We used the cabbage white butterfly, Pieris rapae (L.) (Lepidoptera: Pieridae), to investigate differences in color and testes size in a system that is often exposed to agricultural landscapes with nitrogen addition. We collected individuals from four sites in California and Nevada to investigate variation in key traits and the possibility that any relationship between wing color and a reproductive trait (testes size) could vary among locations in the focal butterfly. Coloration variables and testes size were positively albeit weakly associated across sites, consistent with the hypothesis that females could use nitrogen-based coloration in the cabbage white as an indicator for a male mating trait that has the potential to confer elevated mating success in progeny. However, variation in testes size and in the relationship between testes size and wing color suggest complexities that need exploration, including the possibility that the signal is not of equal value in all populations. Thus these results advance our understanding of complex relationships among environmental change and sexual selection in the wild.
Autonomic Nervous System Response to Far-Infrared Sauna Exposure in Firefighters
Authors: Marciniak Rudi A , Wahl Carly A , Ebersole Kyle T 
Published: September 2021

Abstract

Objectives
Fire departments have employed far-infrared sauna (FIRS) use as part of post-fire call protocols to address concerns related to carcinogens. The inability of the autonomic nervous system (ANS) to fully recover following an emergency call, as demonstrated by heightened sympathetic nervous system activity and delayed parasympathetic nervous system reactivation, has been implicated as a potential factor related to sudden cardiac death. The use of a sauna post-fire call, which has been demonstrated to elevate body temperature, may interfere with the ability of the ANS to fully recover. The purpose of this study was to examine ANS responses to FIRS exposure in firefighters (FFs) with (EX) and without (NONEX) prior maximal exercise.

Methods
Sixteen career FFs participated in this study. Body temperature (TEMP), heart rate (HR), heart rate variability (HRV), blood pressure (BP), and blood lactate (La─) were measured at the start of each testing session, following a maximal exercise test (EX only), and immediately after a 15-min FIRS exposure for NONEX and EX.

Results
In NONEX, TEMP increased (P &lt; 0.001); however, there was no change in HR, HRV, BP, or La─. In EX, BP remained unchanged while TEMP, HR, and La─ were significantly (P &lt; 0.001) greater than baseline following FIRS exposure and HRV was significantly (P = 0.018) lower than baseline.

Conclusions
These findings indicate that FIRS following maximal exercise did support some ANS recovery, but may interfere with restoration of body temperature and parasympathetic nervous system reactivation, potentially influencing post-call cardiovascular risk in FFs.
Evolutionary diversification in the hyper-diverse montane forests of the tropical Andes: radiation ofMacrocarpaea(Gentianaceae) and the possible role of range expansion
Authors: Vieu Julien C , Hughes Colin E , Kissling Jonathan , Grant Jason R 
Published: September 2021

AbstractThe humid mid-elevation montane forests (MMF) of the tropical Andes harbour high levels of plant species diversity, contributing to the exceptional overall diversity of the tropical Andean biodiversity hotspot. However, little is known about the diversification dynamics of MMF plant lineages compared to lineages in other Andean biomes. Here, we use Macrocarpaea (Gentianaceae) to investigate patterns of plant diversification in the MMF, using molecular dating with fossils and secondary calibration (from a family-wide phylogenetic analysis of Gentianaceae). We sequenced 76 of 118 recognized Macrocarpaea spp. for six markers to reconstruct a time-calibrated phylogenetic tree and infer the historical biogeography of Macrocarpaea using maximum-likelihood methods implemented in BioGeoBEARS, estimating diversification rates through time and among lineages with BAMM. We document a rapid radiation of Macrocarpaea in Andean MMF coinciding with rapid colonization and range expansion across the entire distribution of the genus in the Andes starting 7.2 Mya. Our results support allopatric founder-event speciation as the dominant process contributing to geographical phylogenetic structure across the genus. We propose that establishment of the MMF in the late Miocene, when the Andes attained critical elevation to modify regional climates, provided large new areas of suitable habitat for Macrocarpaea to quickly colonize and expand through repeated founder-events. We suggest that this wave of colonization and range expansion triggered rapid diversification, and, as the MMF became progressively occupied, the diversification rate slowed. Our study also supports the idea that MMF plant radiations are older and more slowly evolving than the quickly evolving lineages in the recent Andean high-elevation grasslands.
Childhood Background Measures and Their Associations With Later-Life Physical, Mental, and Social Health in the National Social Life, Health, and Aging Project
Authors: Lee Haena , Choi Kyung Won , Waite Linda J 
Published: September 2021

AbstractObjectiveWe describe each childhood background measure available in the National Social Life, Health, and Aging Project (NSHAP), report preliminary population estimates for each measure by age and gender, and validate the childhood measures by showing that the associations between the NSHAP childhood measures and later-life health outcomes are consistent with previous studies on this topic.MethodChildhood background measures included family life happiness, family structure, parental educational attainment, perceived financial situation, experience of violence, witness of violence, childhood health, and place of birth. We measured self-rated health, depressive symptoms, and social support to assess later-life physical, mental, and social health. Logistic and linear regression models were used for the binary and continuous outcome variables, respectively.ResultsOlder age groups were more likely than those in younger age groups to report a poor financial situation in childhood, lower parental education, and intact family structure and were less likely to have experienced or witnessed a violent event as a child. Growing up in a happy and well-educated family was associated with better physical, mental, and social health in older ages.DiscussionNSHAP childhood data included a variety of measures assessing the family social environment during childhood, providing a valuable resource for the study of early-life determinants of health and well-being over the life course.
A North Star for Gerontology: Using the Threshold Concept Framework to Transform Ageism Education
Authors: Janssen Leah M , Flores Valerie , Cao Jiawei 
Published: September 2021

Abstract
Threshold concepts are fundamental to the learning process and are said to transform the way we view and understand the world around us. Although a new framework to gerontology, the threshold concept framework has been utilized in many fields inside (e.g., psychology, social work) and outside (e.g., clinical and research settings) of academia. This framework facilitates understanding learning, exposing expert blind spots, and designing curricula for complex concepts that are challenging to learn. For decades gerontologists have grappled with ageism and its dire consequences including unemployment, negative health outcomes, and rationing of health care. Education is one of, if not the most, powerful tools to combat ageism. This article demonstrates the utility of the threshold concept framework for gerontologists by conceptualizing ageism as a threshold concept. The purpose of this article is to provide an innovative approach to education on complex gerontological topics in different clinical, research, and educational settings using ageism as a primary example of a threshold concept in gerontology.
Not So Fast: Strike Kinematics of the Araneoid Trap-Jaw Spider Pararchaea alba (Malkaridae: Pararchaeinae)
Authors: Kallal Robert J , Elias Damian O , Wood Hannah M 
Published: September 2021

Synopsis
To capture prey otherwise unattainable by muscle function alone, some animal lineages have evolved movements that are driven by stored elastic energy, producing movements of remarkable speed and force. One such example that has evolved multiple times is a trap-jaw mechanism, in which the mouthparts of an animal are loaded with energy as they open to a wide gape and then, when triggered to close, produce a terrific force. Within the spiders (Araneae), this type of attack has thus far solely been documented in the palpimanoid family Mecysmaucheniidae but a similar morphology has also been observed in the distantly related araneoid subfamily Pararchaeinae, leading to speculation of a trap-jaw attack in that lineage as well. Here, using high-speed videography, we test whether cheliceral strike power output suggests elastic-driven movements in the pararchaeine Pararchaea alba. The strike speed attained places P. alba as a moderately fast striker exceeding the slowest mecysmaucheniids, but failing to the reach the most extreme high-speed strikers that have elastic-driven mechanisms. Using microcomputed tomography, we compare the morphology of P. alba chelicerae in the resting and open positions, and their related musculature, and based on results propose a mechanism for cheliceral strike function that includes a torque reversal latching mechanism. Similar to the distantly related trap-jaw mecysmaucheniid spiders, the unusual prosoma morphology in P. alba seemingly allows for highly maneuverable chelicerae with a much wider gape than typical spiders, suggesting that increasingly maneuverable joints coupled with a latching mechanism may serve as a precursor to elastic-driven movements.