Journal articles on the topic 'Hansel Spittel'

In the present work, a critical analysis of the most-commonly used analytical models and recently introduced ANN-based models was performed to evaluate their predictive accuracy within and outside the experimental interval used to generate them. The high-temperature deformation behavior of a medium carbon steel was studied over a wide range of strains, strain rates, and temperatures using hot compression tests on a Gleeble-3800. The experimental flow curves were modeled using the Johnson–Cook, Modified-Zerilli–Armstrong, Hansel–Spittel, Arrhenius, and PTM models, as well as an ANN model. The mean absolute relative error and root-mean-squared error values were used to quantify the predictive accuracy of the models analyzed. The results indicated that the Johnson–Cook and Modified-Zerilli–Armstrong models had a significant error, while the Hansel–Spittel, PTM, and Arrhenius models were able to predict the behavior of this alloy. The ANN model showed excellent agreement between the predicted and experimental flow curves, with an error of less than 0.62%. To validate the performance, the ability to interpolate and extrapolate the experimental data was also tested. The Hansel–Spittel, PTM, and Arrhenius models showed good interpolation and extrapolation capabilities. However, the ANN model was the most-powerful of all the models.

The constitutive model is still not available for theoretical and engineering analysis of HNi55-7-4-2 alloy, which is a new type of wear-resistant brass alloy widely applied to car synchronizer rings and ship condenser tubes etc. In the current investigation, a friction-corrected stress-strain curve was obtained through a hot-compression test to develop the high-temperature constitutive model of HNi55-7-4-2 alloy based on the Hansel–Spittel model. By comparing predicted flow stress and a simulated force-stroke curve with experimental results, the proposed constitutive model was verified. The developed constitutive model was applied to numerically simulate the hot precision forging of a synchronizer ring. The simulation results based on two process plans on material flow and forging defects were validated by process experiment. The Hansel–Spittel high-temperature constitutive model proposed in this work enables the theoretical and engineering analysis of HNi55-7-4-2 alloy.

The present research paper concerns a numerical and experimental analysis of the tribologic and rheological constitutive behavior influence on prediction of metallic material forging fibering. Numerical analysis using finite element Forge® code and Abaqus software show the high importance of the friction law formulation and of the material rheological softening on the fibers morphology and on their position coordinates. Calibration and sensitivity of friction law together with the numerical sensitivity of the softening term corresponding to a Hansel-Spittel rheological equation have been studied for a cylindrical crushing test of a 16MnCr5 steel.

As a novel kind of cold roller steel, Cr8 alloy steel has the characteristics of high hardness, high wear resistance and good toughness, which can effectively prolong the service life of the roller that is an important part of the steel rolling mill. How to accurately define the constitutive model parameters of metal materials is the major problem, because it seriously affects the accuracy of numerical simulation results of the roller hot forming process. In the study of Cr8 alloy steel’s thermal deformation behavior of the present paper, the high temperature compression test was done on a Gleebel-1500D thermal/force simulation testing machine. A novel method of parameter identification was proposed based on inverse optimization. The Hansel–Spittel constitutive model was established by using the inverse optimization method. To carry out the verification on the accuracy of the established constitutive model, the predicted flow-stress of constitutive model was made a contrast to the experimental flow-stress, and the standard statistical parameters were also applied to further evaluation. The results showed a relatively high prediction accuracy of the Hansel–Spittel constitutive model based on the inverse optimization algorithm. Meanwhile, to obtain optimal parameters of Cr8 alloy steel in the thermal processing, 3D thermal processing maps concerning strain-rate, strain and temperature were built based on the dynamic material model. According to the 3D processing map, the most adequate thermal processing parameters of Cr8 alloy steel were obtianed as follows: strain 0.2–0.4, strain-rate 0.05–0.005 s−1, temperature 1100–1150 °C.

Purpose. The purpose of this work is to clarify the temperature-deformation modes of pressing pipes of titanium alloys (VT1-0, PT-7M, VT-14, VT-15, TS-5 and TS-6) and to determine the regression coefficients of the Hansel-Spittel equation by investigating plasticity and the deformation resistance during hot rotation of the specimens.Methodology. Studies on torsion were performed on a torsion test machine with a horizontal electronic force meter, with a maximum torque of 100 H × m, temperature. The maximum temperature of the test specimens was 1250 °C. Active capture of the test machine has a smooth rotation control from 5 to 200 rpm. Applying specimens with different aspect ratio to the length of the workpiece obtained a range of change of strain rates from 0.25 to 20 с-1.Findings. The main results of the study should be considered experimentally determined curves of the torque dependence on the angle of rotation of the sample to change the resistance of deformation of the metal, which allowed to clarify the temperature interval of maximum ductility during pressure treatment for alloys VT1-0, PT-7M, VT-14, VT-15, TS-5 and TS-6. Based on the data obtained on the deformation resistance, the coefficients of the Hansel-Spittel equation, which can be used to quantify the resulting stress in numerical simulation using the finite element method, have been statistically calculated.Originality. The data on experimentally determined regularities of influence of temperature-deformation modes of torsion on the change of the value of deformation resistance, which is characteristic of conditions of hot pressing of pipes, have been further developed. This allows to predict the power parameters of the deformation process, as well as to select the press equipment and improve the productivity of the press line.Practical implications. Studies on torsion have allowed to determine rational temperature-speed parameters of the process of pressing pipes from titanium alloys VT1-0, PT-7M, VT-14, VT-15, TS-5 and TS-6, for capacities of Ukrainian enterprises.

The 6061 aluminum alloy is extensively utilized in the production of aircraft components, valve parts, and maritime equipment, owing to its exceptional corrosion resistance, weldability, machinability, and anodic oxidation performance. This study investigates the effects of different heat treatment parameters on the mechanical properties of 6061 aluminum alloy. A series of orthogonal experiments were conducted, including quasi-static tensile tests using a QJBV212F-300KN universal testing machine following different solution and aging treatments. Scanning electron microscopy (SEM) was employed for microstructural characterization, revealing the mechanisms by which different heat treatment conditions impact the alloy’s mechanical properties. The test results indicate that the plasticity of 6061 aluminum alloy improves progressively within the temperature range of 510 °C to 540 °C. However, when the solution treatment temperature is elevated to 570 °C, significant grain coarsening occurs, leading to increased brittleness at the grain boundaries and reduced plasticity. Additionally, the elongation of 6061 aluminum alloy initially decreases and then increases as the aging time increases. Based on the experiments, a Hansel–Spittel constitutive model was developed, incorporating temperature, strain rate, and strain effects to accurately predict the flow stress of 6061 aluminum alloy under varying heat treatment conditions.

Large size forged ingots, made of high strength steel, are widely used in aerospace, transport and energy applications. The presence of internal voids in the as-cast ingot may significantly affect the mechanical properties of final products. Thus, such internal defects must be eliminated during first steps of the open die forging process. In this paper, the effect of in-billet void positioning on void closure throughout the ingot breakdown process and specifically the upsetting step in a large ingot size steel is quantitatively investigated. The developed Hansel-Spittel material model for new high strength steel is used in this study. The ingot forging process (3D simulation) was simulated with Forge NxT 1.0® according to existing industrial data. A degree of closure of ten virtual existing voids was evaluated using a semi-analytical void closure model. It is found that the upsetting process is most effective for void closure in core regions and central upper billet including certain areas within the dead metal zone (DMZ). The volumetric strain rate is determined and two types of inertial effects are observed. The dependence of void closure on accumulated equivalent deformation is calculated and discussed in relation to void in-billet locations. The original combination of information from both relative void closure and the volumetric strain rate provides a way to optimize the forging process in terms of void elimination.

X12 (X12CrMoWVNbN10-1-1) ferritic heat resistant steel is an important material for the production of new-generation ultra-supercritical generator rotors. Hot compression tests of X12 ferritic heat-resistant steel were performed via a Gleeble-1500D testing machine under temperatures of 1050–1250 °C and strain rates of 0.05–5 s−1. In order to provide material model data for finite element simulations and accurately predict the hot deformation behavior, a reverse optimization method was proposed to construct elevated temperature constitutive models of X12 ferritic heat-resistant steel in this paper, according to the Hansel–Spittel constitutive model. To verify the accuracy of the model, the predicted and experimental values of the constitutive model were compared. The results indicated that the model had a high prediction accuracy. Meanwhile, the correlation coefficient between the experimental value and the predicted value of constitutive model was 0.97833. For further verification of the accuracy of the model, it was implemented in finite element FORGE@ software to simulate the compression tests of different samples under different conditions. Comparing actual displacement–load curves with displacement–load curves acquired through finite element simulations, the results indicated that displacement–load curves predicted by the model were very consistent with actual displacement–load curves, which verified the accuracy of the model. Moreover, to research the optimal processing parameters of the material, hot processing maps were drawn according to the dynamic material model. In terms of microstructure evolution, a characteristic area distribution map of the hot processing map was established. Therefore, the optimal hot forming parameters regions were in the range of 1150–1200 °C/0.05–0.62 s−1 for X12 ferritic heat-resistant steel.

Inconel 718 is a well-known nickel-based superalloy used for high-temperature applications. The aim of the present study was to formulate a constitutive equation (CE) that can be used to account for the deformation behavior of Inconel 718. Compression tests were performed using Gleeble 3800, a thermomechanical simulator, at temperatures ranging from 900 to 1200 °C, at strain rates varying from 0.1 to 10/s. Before compression tests, each specimen was rapidly heated to the desired test temperature while the initial contact pressure was kept relatively low. Thus, compression was performed while the temperature of the entire system, including the specimen and the die, was not uniform. Before conducting an upsetting finite element analysis to determine CE parameters, the heating conditions applied in the Gleeble tests were first subjected to a Joule heating analysis, to simulate the temperature distribution in each specimen prior to the compression process. The spatial temperature distribution of the specimen and the die were determined using a Joule heating analysis, and these results were used as input data for the subsequent finite element analysis of the compression process. From this, the parameters in the obtained Hansel–Spittel equation were estimated for each temperature condition, by employing the regression optimization method, which was used to minimize the deviation between experimental and simulated load values. To validate this optimization process, the experimentally measured flow stresses with respect to the strain rate for each temperature condition were compared with the forming load, determined by the finite element analysis of the compression process using the optimized CE obtained in the present study. It was confirmed that when the optimization process was applied, there was a decrease in the root mean square error. The major findings confirmed the validity of the CE optimization method combined with Joule heating analysis for determining the CE’s parameters for high-temperature applications.

Titanium alloy is widely applied in aerospace, medical, shipping and other fields due to its high specific strength and low density. The purpose of this study was to analyze the formability of Ti6Al4V alloys at elevated temperatures. An accurate constitutive model is the basic condition for accurately simulating the plastic forming of materials, and it is an important basis for optimizing the parameters of the hot forging forming process. In this study, the optimization algorithm was used to accurately identify the high-temperature constitutive model parameters of Ti6Al4V titanium alloy, and the hot working diagram was established to optimize the hot forming process parameters. The optimal forming conditions of Ti6Al4V titanium alloy are given. Ti6Al4V alloy was subjected to high-temperature compression tests at 800–1000 °C and at strain rates of 0.01–5 s−1 on a Gleeble-1500D thermal/mechanical simulation machine. Each parameter of the Hansel–Spittel constitutive model was taken as an independent variable, and the accumulated error between the stress calculated by the constitutive model and the stress obtained by experimentation was used as an objective function. Based on response surface methodology, an inverse optimization method for identifying the parameters of the high-temperature constitutive model of Ti6Al4V alloy is proposed in this paper. An orthogonal test design was adopted to obtain sample point data, and a third-order response surface approximate model was established. The genetic algorithm (GA) was applied to reversely optimize the parameters of the constitutive model. To verify the accuracy of the optimized constitutive model, the average absolute relative error (AARE) and correlation coefficient (R) were used to evaluate the reliability of optimized constitutive model. The R value of the model was 0.999, and the AARE value was 0.048, respectively, indicating that the established high-temperature constitutive model for Ti6Al4V alloy has good calculation accuracy. The flow stress behavior of the material could be accurately delineated. Meanwhile, in order to study the formability of Ti6Al4V alloy, the hot processing map of the alloy, based on a dynamic material model, was established in this paper. The optimum hot working domains of the Ti6Al4V alloy were determined within 840–920 °C/0.01–0.049 s−1 and 940–980 °C/0.11–1.65 s−1; the hot processing map was verified in combination with the microstructure, and the fine and equiaxed grains and a large amount of β phase could be found at 850 °C/0.01 s−1.

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Abstract Two methods are investigated for estimating the phase velocity of diffusely scattered seismic waves simultaneously arriving from different azimuths and recorded by a two-dimensional array of seismometers. The Hankel spectrum is the average of the frequency-wavenumber (FK) spectrum over all azimuths, while the wavenumber spectrum is derived by integrating the FK spectrum around a contour of constant phase velocity, i.e., a circle centered on the origin in the wavenumber plane. If the conventional estimate of the FK spectrum using the covariance matrix of the seismometer signals is integrated, a closed form for both the Hankel spectrum and the wavenumber spectrum may be found; the two spectra are very similar, the wavenumber spectrum being equal to the Hankel spectrum times the wavenumber. In spite of this similarity, however, we find that the two formulations have significantly different behavior for small wavenumbers, i.e., high phase velocities. In both cases there is a highest (true) velocity that can be estimated from the spectral maximum for a given array aperture (“velocity cut-off”). The Hankel spectrum estimates too high a velocity; for true wavenumbers below a certain limit, infinite velocity is estimated. The wavenumber spectrum, on the other hand, estimates too low a velocity, and there is an upper limit on the estimated velocity. An example illustrating these difficulties for the two methods is given for teleseismic P coda of an event recorded at the NORESS array in southern Norway: in spite of the problems, the analysis is able to demonstrate that the coda consists of two components; a coherent P-wave component with a high phase velocity and a diffuse S-wave component of low phase velocity. The cut-off and bias problem are investigated by numerical simulation for the NORESS array using azimuthal averaging and synthetic signals. The results confirm and quantify the cut-off problem at low wavenumbers and indicate that wavenumbers estimated from the Hankel and wavenumber spectra maxima bracket the true wavenumber, with the Hankel spectrum estimate being low (phase velocity too high) and the wavenumber spectrum estimate high. The bias of both methods decreases with increasing wavenumber (decreasing phase velocity) and they are both asymptotically unbiased. The wavenumber spectrum has a superior performance at low wavenumbers (high phase velocity), but the Hankel spectrum gives superior results at high wavenumbers (low phase velocity). The product of the linear wavenumber (= 1/wavelength) and the array aperture define “high” and “low” wavenumbers; for low wavenumbers, the product is 1 or less. In an Appendix, we find absolute lower bounds on the cut-offs analytically. The problems could be mitigated by using high resolution methods.

Uffe Hansen 14.12. 1894 - 11.9. 1994By Henning HøirupThe obituary begins with a description of Uffe Hansen’s background as an Independent Congregation clergyman (from 1925) to the Grundtvigian Independent Congregation (Danish valgmenighed, i.e. a congregation within the National Church, claiming the right to employ their own minister) of Ubberup, where the prominent clergymen V.J.Hoff and Carl Koch were his predecessors. Carl Koch’s extensive writings, theologically erudite, but .popular. in their language, and thus accessible to the layman, were to become the model for Uffe Hansen’s studies in Grundtvig’s hymnwriting. Through his membership of the Hymn Book Commission of the free Grundtvigian congregations (HYMNS. Independent Congregations and Free Church Congregations, 1935), Uffe Hansen was motivated to realize his plan of a complete account of the whole of Grundtvig’s hymn writing in the book Grundtvig’s Hymn Writing. Its History and Content I. 1810-1837, published in 1937. In the following years Uffe Hansen was absorbed in organizational work (Grundtvigian Convent, the »No More War« organization) and by his membership of the Grundtvigian Hymn Book Committee (The Danish Hymn Book. A Grundtvigian Proposal, 1944). In the 1940s efforts were made to unite the hymn tradition of the re-united Southern Jutland with the traditions of the Kingdom, i.e. the old Danish treasury of hymns and the Grundtvigian hymns. Uffe Hansen became a member of the Hymn Book Commission which published the proposal The Danish Hymn Book in 1951. More than anybody else, Uffe Hansen is responsible for the large number of Grundtvig hymns in this proposal, often with verses from the original versions of the hymns added to them. In spite of vehement criticism on this point The Danish Hymn Book was authorized in 1953. Grundtvig remained the predominant contributor, even though significant Grundtvig hymns, expressing his church view, were omitted, much to Uffe Hansen’s regret. The Hymn Book includes Uffe Hansen’s own translation of the Latin antiphone Oh, Grant Us Peace, Our Lord. While this debate was going on, the continuation of Uffe Hansen’s work, Grundtvig9s Hymn Writing II. 1837-1850 appeared in 1951, an important contribution to a comprehensive interpretation of Grundtvig’s work to renew the Danish hymnody. However, Uffe Hansen’s main achievement as a hymn researcher was his work as a co-editor of Grundtvig’s Song-Work I-VI, 1944-1964. This new edition was worked out on scientific principles, and the hymns were brought in chronological order, as far as it was possible. The edition included a critical variant apparatus, compiled by Uffe Hansen. Concurrently with this work, Uffe Hansen participated in the compilation of a Register of Grundtvig’s Posthumous Papers 1-IXXX, 1956-1964, and, while engaged on this, found several hitherto unknown hymns, which were included in the new edition of the Song-Work.Here Uffe Hansen’s abilities as a researcher and scholar were amply demonstrated. Then, in 1966, came his finalwork, Grundtvig’s Hymn Writing III. 1851-1872, which, like the other volumes, testify to Uffe Hansen’s talent for combining erudition with easy comprehensibility. In his last years Uffe Hansen lived in Holland; he was laid to rest from the Independent Congregation Church of Ubberup.

Sigmund Mowinckel created a highly influential interpretation of the Psalter. In this interpretation, Ps 24 played a particularly important role due to its antiphonic style. The antiphonic style of the psalm is widely represented in the reception history of the psalm – especially in classical music. For example, Handel's chorus piece Lift up ye Heads in his oratorio Messiah is structured in an antiphonic manner. Mowinckel’s exegesis and the music composed by Handel have similar structures in their representations of Ps 24 – in spite of the different aims of their interpretations. However, both interpretations are concerned with God’s victory over death. It is fruitful to note the similaritiesof the two interpretations, because they suggest either a Christian hermeneutical background to Mowinckel's enthronement festival or an antiphonic style in the text itself.

Abstract The nature of the bonding in Be metal was studied by investigating the MEM map, which is the electron density distribution obtained by the Maximum-Entropy Method. In order to avoid extinc-tion effects, 19 Bragg reflections were measured by a new powder-diffraction experiment that utilizes Synchrotron Radiation as an incident X-ray and an Imaging Plate as detector. The experiment was carried out at the Photon Factory BL6A2. In spite of the limited number of reflections used in the MEM analysis, the electron density distribution of Be was obtained accurately and reliably. The structure factors for unmeasured reflections were calculated and compared with the values observed by Larsen and Hansen [Acta Cryst. B40, 169 (1984)]. The agreement is very good. Furthermore, the MEM map revealed that Be metal forms an electronic layer in the shape of a honeycomb that is parallel to the basal plane.

Penelitian pemetaan batimetri perairan laut dangkal menggunakan citra satelit Landsat-8 OLI telah dilaksanakan di Perairan Teluk Tambelan Provinsi Kepulauan Riau. Batimetri dilakukan dengan cara teknologi penginderaan jauh melalui gelombang elektromagnetik. Penelitian ini bertujuan unutk melakukan pemetaan batimetri Landsat-8 OLI dari model regresi serta mengetahui model regresi yang cocok dengan data lapangan. Pengolahan citra satelit Landsat-8 OLI menggunakan metode algoritma Van Hangel dan Spitzer. Data hasil kedalaman citra satelit Landsat-8 OLI divalidasi menggunakan data kedalaman lapangan. Hasil dari penelitian digambarkan dalam bentuk peta batimetri Landsat-8 OLI model regresi. Kedalaman model regresi linier berkisar antara -15 sampai 22 meter, model regresi ln 0 sampai 65 meter dan model regresi log 0 meter. Hasil analisis menunjukan bahwa hubungan indeks kedalaman relatif terhadap kedalaman lapangan diperoleh koefisien korelasi regresi linier =0,81, regresi ln koefisien korelasi =0,82 dan regresi log dengan koefisien korelasi =0,78. Hasil kedalaman Landsat-8 OLI model regresi linier berkisar antara 0,24 sampai 17,74 meter dengan rata-rata 9,08 meter. Kedalaman model regresi ln berkisar antara 0,3 sampai 24,2 meter dengan rata-rata 6,7 meter dan model regresi log berkisar antara 0,3 sampai32,6 meter dengan rata-rata 7 meter.

Misinformation has remained challenging in spite of all the innovative strategies and existing regulations. Globally, it has continued to lay a strong grip on society by influencing people’s worldview. Even though the spread of misinformation in the virtual world was majorly investigated as a result of the uncontrollable nature of the medium itself, this study has aimed at understanding the relationship between the need for effortful thinking with the likeliness to share and believe in misinformation by young adults. The study employed a cross sectional design and recruited 384 participants between the ages of 18 and 25 and utilised the Need for cognition scale NCS-6 by Coelho, Hanel, & Wolf, 2018, to measure effortful thinking and a checklist to measure likeliness to share social media messages.The results revealed that high effort thinking in individuals prevents further sharing of misinformation on social media. This study also shed light on the difference in effortful thinking on the basis of religion, education, years of social media usage and location of residence.

AbstractIn the present work, we study the rotations of the polarization of light propagating in right and left-handed films and layered structures. Through the use of complex values representing the rotations we analyze the transmission (Faraday effect) and reflections (Kerr effect) of light. It is shown that the real and imaginary parts of the complex angle of Faraday and Kerr rotations are odd and even functions for the refractive index n, respectively. In the thin film case with left-handed materials there are large resonant enhancements of the reflected Kerr angle that could be obtained experimentally. In the magnetic clock approach, used in the tunneling time problem, two characteristic time components are related to the real and imaginary portions of the complex Faraday rotation angle . The complex angle at the different propagation regimes through a finite stack of alternating right and left-handed materials is analyzed in detail. We found that, in spite of the fact that Re(θ) in the forbidden gap is almost zero, the Im(θ) changes drastically in both value and sign.

The 19th century saw a remarkable innovation of the subject-matter of Danish altarpaintings. Frequently depicting the ministry of Christ and his Glory, these paintings have often been criticized for being skillfully executed but lacking drama, being overly sweet or even sentimental. This article argues that, in spite of the glossy façade, these paintings often engage in far more sinister topics of life and of faith. The article argues that Søren Kierkegaard’s theology offers a superb lens for gaining insights into this side of the religious painting of the so-called ‘Golden Age’ of Danish art and explores the ‘shadows of the glossy images’ through close readings of Danish altar pieces ranging from Bertel Thorvaldsen’s seminal Christ and C. W. Eckersberg’s ground-breaking Incredulity of Thomas to late 19th Century works of art by Constantin Hansen and Anton Dorph. The main argument of the article is that a negative understanding of this world and not least the constant struggle between being separated from, but needing to get (spiritually) closer to the Saviour remain very strong themes in the religious paintings throughout the 1800s, albeit mainly offered as a personal experience and not as a part of the ideal Christ figure.

With the increasing demand for improved machining accuracy in recent years, the problem of thermal deformation of machine tool structures is becoming more critical than ever. In spite of the effort for improving the thermal deformation characteristics of machine tools at the design stage, there are always some residual errors that have to be compensated for during machining. The design of a generic multi-axis control system requires the development of two models to estimate the transient thermal load and to estimate the thermal deformation of the structure in real-time. To satisfy the stringent accuracy and stability requirements of these two models, a new concept of “generalized modelling” is introduced. It combines mathematical modelling with empirical calibration, and is based on the existence of a mathematical similarity between the real process and a simplified model, referred to as the fundamental generalized problem FGP. To obtain an analytical description of the heat transfer and thermal deformation processes in machine tool structures, an analytical solution of the FGP, which consists of an infinite plate with a central ring heat source, is derived using Hankel transformation. Computer-simulated test cases are presented to demonstrate the use of generalized modelling for predicting the transient thermal response in a complex machine tool structure. It was also shown how the generalized model can accurately extrapolate limited measurement data to predict the entire temperature field. The results confirmed that the generalized model can reproduce the accuracy of the finite-element solution, but two orders of magnitude faster.

1. Regional specialization within the triple compound eyes of the gonodactyloid stomatopod Gonodactylus oerstedii (Hansen) was studied by examining how ocular tracking of a small target was affected after occluding vision in particular ommatidial regions with black enamel paint. 2. Complete occlusion of one eye did not prevent the other eye from tracking, indicating that the two eyes act somewhat independently. However, following such treatment, the angular extent over which the seeing eye moved while tracking was reduced. 3. An eye was able to continue tracking a moving target even after occlusion of the anterior tip or after painting over all of its posterior surface except the anterior tip (restricting the visual field to a patch about 40° in diameter). Similarly, occlusion of only the midband, the medial half or the lateral half of an eye did not prevent tracking. 4. Tracking was also possible, although with decreased amplitude, when either the dorsal or the ventral hemisphere was occluded. However, when both the dorsal and ventral hemispheres were occluded, leaving only the midband for vision, the ability of an eye to track was abolished. 5. A computer model was used to investigate whether the midband alone had the potential to direct tracking in our experiments. The model's output predicts that, in spite of its restricted field of view, if the midband is oriented within 20° of the horizontal, an eye could track using the midband alone. Conditions favoring such potential tracking occurred in our experiments, but neither tracking nor targetting movements were observed. 6. We conclude that ommatidia of the dorsal and ventral hemispheres of each compound eye are essential for ocular tracking in G. oerstedii. The midband appears to play no major role in this activity. Note: Present address: Department of Zoology, The University of Maryland College Park, College Park, MD 20742, USA.

It behoves a media philosophical appraisal of the computer game—invested as media philosophy is in how media engender modalities of thought — to grapple with the computer game’s heritage. Specifically, the essay addresses an issue raised by attention to the computer game’s historical intertwinement with the military and industry: the extent to which these cybernetic machines, overdetermined by their techno-epistemic conditions, continue to perpetuate the ways of thinking from which they derived. The first section of the essay reconstructs parts of this history, drawing primarily on Claus Pias’s computer game genealogy: Computer Game Worlds (2017). It pays particular attention to how the prehistory of time-critical action games reveals their close relationship with and tacit optimization of player pre-reflective perceptual and sensorimotor capacities. The second section considers the lasting implications of the computer game’s historical a priori vis-à-vis their propensity to train their users. It engages with Patrick Crogan’s argument in Gameplay Mode (2011) that computer games are the “reproduction rather than simply the ‘product’ of […] Cold War mentality” and foregrounds his claims as important considerations for any attempt to think media philosophically with and through the medium (2011, p.105). That said, the essay concludes recouping the computer game by way of the very training function it appears condemnable for. Drawing on Mark Hansen (2000), my contention is that Pias and Crogan place in relief what I figure as a creative consequence of computer game play with implications for media philosophy: brokering our corporeal, pre-reflective adaptation to and, thus, agency within our contemporary lifeworld. It is by virtue of, not in spite of, computer games cybernetically working on us that they potentiate ways of thinking about and living in digital culture.

By means of the Hankel transform and dual-integral equations, the nonlinear response of a penny-shaped dielectric crack with a permittivity κ0 in a transversely isotropic piezoelectric ceramic is solved under the applied tensile stress σzA and electric displacement DzA. The solution is given through the universal relation, Dc∕σzA=KD∕KI=MD∕Mσ, regardless of the electric boundary conditions of the crack, where Dc is the effective electric displacement of the crack medium, and KD and KI are the electric displacement and the stress intensity factors, respectively. The proportional constant MD∕Mσ has been derived and found to have the characteristics: (i) for an impermeable crack it is equal to DzA∕σzA; (ii) for a permeable one it is only a function of the ceramic property; and (iii) for a dielectric crack with a finite κ0 it depends on the ceramic property, the κ0 itself, and the applied σzA and DzA. The latter dependence makes the response of the dielectric crack nonlinear. This nonlinear response is found to be further controlled by a critical state (σc,DzA), through which all the Dc versus σzA curves must pass, regardless of the value of κ0. When σzA<σc, the response of an impermeable crack serves as an upper bound, whereas that of the permeable one serves as the lower bound, and when σzA>σc the situation is exactly reversed. The response of a dielectric crack with any κ0 always lies within these bounds. Under a negative DzA, our solutions further reveal the existence of a critical κ*, given by κ*=−RDzA, and a critical D*, given by D*=−κ0∕R (R depends only on the ceramic property), such that when κ0>κ* or when ∣DzA∣<∣D*∣, the effective Dc will still remain positive in spite of the negative DzA.

Organic electrosynthesis is regarded as a sustainable alternative to traditional organic synthesis as it enables replacement of stochiometric redox agents with electricity – which can be generated from renewable sources – and high product selectivity at ambient conditions [1]. However, the poor conductivity of the organic solvents typically requires the addition of large amounts of supporting electrolyte salts, leading to increased waste generation and lowered atom economy of the process. Alternative solvents such as room temperature ionic liquids (RTILs) and deep eutectic solvents (DESs) represent a promising alternative electrolyte and solvent in electrosynthesis. They are conducting, non-volatile and able to solubilize several organic compounds as well as easily separated from products by extraction and thus prone for reuse [2-4]. In addition, they have a tunable, large electrochemical window and this has already led to their use as electrolytes in other fields of electrochemistry, including batteries, electrochromic devices, supercapacitors and in electrodeposition processes [5-6]. DESs offer some advantages compared to RTILs, including that their synthesis is comparable inexpensive and simple, requiring no purification. In addition, some of the DES are biodegradable. DESs have already been use in organic synthesis as solvents and catalysts, however only few examples use DESs as electrolyte systems in organic electrosynthesis despite their advantageous properties. DESs can also solubilize untreated biomass and biomass components, and thus they are attractive solvents for several biorefinery processes including pretreatment, fractionation, and catalytic conversion [7]. Selective reductive transformations are key in biomass valorization to yield precursors for fuels and chemicals. In this work, we show how DESs can play a dual role as solvent and electrolyte for reductive transformations of organic compounds. The physical and electrochemical properties of the DESs and their role in the reaction are investigated. In addition, the feasibility of reusing the DES over several reactions is examined. [1] Frontana-Uribe, B.A.; Little, R. D.; Ibanez, J. G.; Palma, A. & Vasquez-Medrano, R. Green Chem. 2010, 12, 2099-2119. [2] Singh, S. K. & Savoy, A. W. J. Mol. Liquids 2020, 297, 1120938 [3] Hansen, B. B.; Spittle, S.; Chen, B.; Poe, D.; Zhang; Y., Klein; J. M.; Horton, A.; Adhikari, L.; Zelovich, T.; Doherty, B. W.; Gurkan, B.; Maginn, E. J.; Ragauskas, A.; Dadmun, M.; Zawodzinski, T. A.; Baker, G. A.; Tuckerman, M. E.; Savinell, R. F. & Sangoro, J. R. Chem. Rev. 2021, 121, 1232–1285. [4] Kathiresan, M., & Velayutham, D. Chem. Commun. 2015, 51, 17499. [5] Armand, M.; Endres, F.; MacFarlane, D. R.; Ohno, H. & Scrosati, B. Nat. Mater. 2009, 8, 621–629. [6] Abbott, A. P. Curr. Opin. Green Sustain. Chem. 2022, 36, 100649. [7] Wang, Y.; Kim, K. H.; Jeong, K.; Kim, N. K.; Yoo, C. G. Curr. Opin. Green Sustain. Chem. 2021, 27, 100396.

The popularity of Isabel Flores de Oliva, commonly known as Saint Rose of Lima, in the Latin America iconosphere has endured since the 17th century and is still spectacular. Images of this Third Order of St. Dominic member proliferated soon after her demise (1617), not only in the New World, but also in Europe, multiplied in countless cheap copies. Nevertheless, her person also inspired renowned artists as famous as Bartolomé Esteban Murillo, sevillian Juan de Valdes Leal or cordoban Antonio Palomino. Even before canonisation (1671), the fame of the Peruvian ascetic reached the Polish-Lithuanian Commonwealth, due to the efforts of the Order of Preachers, i.a. Tomasz Tomicki O.P., who translated into Polish the Latin biography of Isabel Flores de Oliva written by Leonard Hansen O.P. Tomicki’s book, which was printed in Cracow in 1666, contains the first known Polish image of the future saint. The year of canonisation is also a date of establishing first devotional paintings for Dominican churches in the major cities of the Polish-Lithuanian Commonwealth. An oil painting attributed to Tomasz Muszyński in Warsaw St. Hyacinth’s Church presents St. Rose among other Dominicans active in the New World: Martin de Porres, John Macías and Vicente Bernedo. Paintings for an altar in St. Nicholas church in Gdańsk (“Saint Rose with the Child Jesus” and “The Vision of Saint Rose”) were made by Andreas Stech, a popular artist active in this city. Apart from that, we know quite a numerous range of anonymous devotional images of St. Rose of Lima – or at least pieces passing for her images. “The Catalogues of Art Monuments in Poland” – an inventory published by the Polish Academy of Science Institute of Art – enumerate over a dozen paintings and sculptures devoted to the ascetic from Peru, which can be found in various places within the present borders of Poland: i.a. Brześć Kujawski, Hrubieszów, Klimontów, Kraków, Kraśnik, Mokobody, Markowice, Niwiski, Piaski, Sandomierz, Staszów, Turobin, Zaręby Kościelne. However, not all art historians agree with such recognition; there are arguments that in some cases we are faced with images of St. Catherine of Siena rather than St. Rose. In spite of these doubts, it is proved that Isabel Flores de Oliva gained her own place in the iconography of Polish Dominicans and played a significant role in their efforts to promote certain forms of spirituality.

Background. The creative life of Ludwig Spohr (1784–1859) coincides with at least three historically-cultural periods: Late-Classical, Romantic and LateRomantic, thus creating a straight line from Classical works of XVIII century to those of the middle of XIX century. First works by Spohr having opus number chronologically coincide with the beginning of Beethoven’s central period of life, and in this light, he is rather seen as heir of pre-Beethoven generation of composers. But, having outlived the last Viennese Classicist by 32 years, Spohr assimilated both his experience and innovations of the new generation of musicians, his junior contemporaries. In spite of the fact that Spohr wasn’t inclined to radical innovations, unlike his coeval Weber, he became one of the first harbinger of the new music. Yet we should note that situation of drastic change of musical culture, in which the composer was brought up, programmed his lifestyle and general direction of his creativity. Moreover, “intersection of times” defined contradictions in Spohr’s legacy, that hitherto hurdle his unambiguous evaluation. Literature review. It would be unfair to state that name of Spohr doesn’ figure in musicologists’ researches at all. Although one has to admit that while in Western musicology a certain tradition of studying his creative life has been established, in Soviet and post-Soviet scientific area creativity of Spohr hasn’t ever become on object of separate dissection, with a single exception of Raaben’s essay (Raaben, 1967). But even in this work Spohr only listed alongside with other musicians, but not as a self-sufficient phenomenon. Scattered facts of Spohr’s creative life are incorporated into brief outlines of his works or spheres of activity, created by M. Cherkashyna (1998), N. Antipova (2007), V. Ferman (1961), V. Pluzhnikov (2006). Researches are actively trying to reveal diverse connections between Spohr and the past of the musical culture: his “Mozartness” (Heussner, 1957), efforts to revive music by Bach, Handel and other masters of the past (Homburg, 1958; 1960). Much less attention is drawn to historical typology of Spohr’s legacy, to his place in the spacetime of music. H. Riemann (1961) regards him as a Romantic composer, having more in common with Shubert and Mendelssohn than with Weber, Schumann and Marschner. K. Huschke (1939) notes his soft, elegiac and lofty feelings, beauty of the melodies, his nobility in stark contrast with Weber’s art founded in folk intonations, although claiming both of them to be German in spirit. Although wholistic image of Spohr in research literature, unfortunately, has not been created yet. The aim of this paper is an attempt to present complex creative personality of Spohr, comprised of the opposite constituents, as a whole. Results. On the verge of XVIII–XIX centuries even tradition, that is one of the most profound and fundamental factors of culturally-historical process, is subjected to reconsideration. For Spohr, tradition means mainly possessing skills, professionality. Spohr endeavoured mastership in every single thing he did: practicing violin 10 hours daily, polishing his Kapellmeister art, or embodying appearing musical ideas in his compositions. It was rather predictable that he had become one of the most prominent pedagogues of XIX century, progenitor of violin school and glorious Violinschule. According to the tradition dating back to the Baroque era, Spohr reveals a tendency towards inventio: both in the terms of technology (invention of a chinrest) and in creativity. In the latter case inherited meets modern. Spohr precisely formulates artistic ideas appearing to him thus becoming one of their generators. Spohr’s attitude to tradition can be understood through his favouring of musical classics as vivid reality. Almost all scholars of his legacy unanimously agree that he had enormous adoration of Mozart during all his life. One may say that in mind of Spohr two different approaches to tradition overlap: from the standpoint of XVIII century (when it was regarded as a continuity of knowledge, well-developed skills, order) and from the vantage of XIX century (as an object of reconsideration, adaptation in the context of new stylistic system and Romantic worldview). Not only did ambiguous approach to the tradition defined his art, but also affected societal, political views, spheres of activity and personal traits. Conclusions. Observations on creative life of Spohr allow to demonstrate paradoxes of his personality. He was simultaneously a court musician and a “free artist”; a proponent of musical past and critic of the modernity – and its indefatigable champion as opera Kapellmeister and as symphonic and concert conductor; performer-virtuoso – and serious, ruminant creator of large-scale oratorios, operas and symphonic conceptions; advocate for normativity in art – and pioneer in many respects, – these are pairs-oppositions defining the image of Spohr’s personality.

Background. The academic guitar art, which announced itself at the beginning of the XXI century as one of the dominant and sought-after forms of the concert music making, in recent decades has become the subject of scientific reflection. However, due to a later start time of its evolvement, it turned out to be less explored than other concert genres. The birth of the academic guitar art in the early twentieth century associated with the name of A. Segovia, together with whose creativity it stepped beyond the limits of the Spanish national culture and came to the world level. Creativity of the contemporaries and compatriots of A. Segovia, the famous guitarists of the first half of the twentieth century C. Romero, R. S&#225;inz de la Maza and M. Llobet, did not have that cultural and artistic weight, which could be a basis for ascension of the Spanish guitar art to the European professional heights. Exactly A. Segovia was able to do this. In spite of the fact that the importance of A. Segovia’s activities for the formation of the new performing guitar traditions of the twentieth century is enormous, it has not yet received its systemic coverage. Thus, the relevance of this article is caused, on the one hand, by the great interest in the academic guitar art in recent years, and on the other, by the lack of the special scientific studies dedicated to the performing art of the outstanding Spanish guitarist. Existing studies contain only incomplete historical data [3; 7] or the compressed socio-cultural panorama of A. Segovia’s creative activity and the period of formation of the guitar performing traditions of the twentieth century [1, p. 4–6]. Objectives. The proposed research considers the features of the performing art of A. Segovia at its different stages in order to identify the patterns of its evolvement and the main its achievements from the point of view of the contemporary guitar art. For the first time, a comprehensive assessment of the concert heritage of the Spanish maestro in the aspect of its legislative influence upon the modern academic guitar creativity is given. Methods of the research. The complex of general scientific research methods makes it possible to disclose the basic positions of the article: signification of the classical guitar in the family of the academic solo instruments (systems approach); the evolution paths of an academic guitar (historical approach); comprehension of the guitar creativity in a broad socio-cultural aspect (cultural approach); definition of the author’s performing style of A. Segovia (interpretational approach). Results. For comprehension of the evolution of A. Segovia’s performing arts, maestro’ concert programs are considered. The first big performance (March 12, 1916) included 19 pieces (Par I – the arrangements by A. Segovia and one piece by M. Llobet; Part II – the works by J. Bach, J. Haydn, F. Mendelssohn, F. Chopin, all transcribed for guitar by F. T&#225;rrega; Part III – the music by I. Albeniz, E. Granados and one play by P. Tchaikovsky). At this stage of evolution of the academic guitar art, A. Segovia could not present in the program the works of the Renaissance epoch; besides, in the historical and cultural aspect, the program is formatted inconsequently. However, in our opinion, the program is logical and justified in its own way, and its third part that almost entirely formed from the works of the Spanish national classics one can consider as a response to the ideology of “Renacimiento” – the movement for the national revival of Spain. The ending of the decade of the fruitful concert activity of A. Segovia coincided with his tours in the territory of present-day Russia and Ukraine. In 1926, A. Segovia gave six concerts in Moscow and two concerts in Leningrad, and in 1927 – six concerts in Moscow, three concerts in Leningrad, and one each in Kharkov and Kiev. The analysis shows that the total number of works in A. Segovia’s repertoire list during his Moscow tour performances in 1926–1927 has grown to 75. They belonged to different historical eras and various performing styles, to 28 authors from different countries. The extensive repertoire corresponding to A. Segovia’s exquisite taste embodied in elegant performing interpretations, which reflected in the feedback from listeners and music critics. Over 10 years of his concert activity, the total repertoire of A. Segovia expanded significantly (up to 300 works), not only due to his own transcriptions of works by J. Bach, G. Handel, W. Mozart, J. Haydn, F. Schubert, F. T&#225;rrega, I. Albeniz and E. Granados, but also thanks to the works of a new wave of composers: A. Tansman, F. Moreno Torroba, J. Turina, which created a number of pieces for guitar at the request of A. Segovia. Conclusions. Thus, contingently, A. Segovia’s concert activity one can divide into two big stages: before and after 1924. The culmination point of the first stage is related with the successful performance in Barcelona (1916), which eliminated some acoustic and psychological barriers that hampered guitar performers and organizers of concerts (A. Segovia is the first guitarist who was playing in the hall for 1000 seats). The first tour in Paris in April 1924, which began the second stage of the maestro’s concert activity, can be considered as a landmark event on the path of world recognition of A. Segovia. Henceforth the format of the concert programs of A. Segovia and his recordings on disks thought out clearly, it is structured delicately based on the musical styles of certain historical periods. An important place the works of modern composers occupied. The concert heritage of A. Segovia is a reflection of the evolution of the guitar repertoire. It progressed from the limited by the previous tradition in the early twentieth century up to the universal format, combining the best examples of the folk music (flamenco), the transcriptions of European classical music and the modern works bearing the newest sound images. Among the authors of such, at the request of A. Segovia, were M. Castelnuovo-Tedesko, F. Moreno Torroba, M. Ponce, J. Rodrigo, A. Tansman.

This paper introduces a probabilistic approach for predicting the lifetime of extrusion dies using a structural reliability method known as stress-strength interference. In our investigation, we have integrated the assessment of the die's cycle life by following behavioral and rheological law. The approach relies on estimating the reliability index through a combination of a behavioral model and a reliability analysis of the hot extrusion process. Subsequently, the reliability analysis is conducted using a mechanical model to depict the most likely failure conditions. In this regard, the rheological law of Hansel & Spittel emerges as the most suitable choice, as it incorporates the mechanical properties of the materials employed in the fabrication of hot tools. The proposed mechano-reliability approach enables us to estimate reliability and its sensitivity by adjusting the parameters controlling the input process in die formation. Numerous scenarios involving extrusion dies were considered. The results demonstrate that temperature's impact on the die during the extrusion process is manifested through fatigue and damage parameters, as well as the first equivalent strain, which affect the evolution of the reliability index β and subsequently enhance the number of billets extruded.

Abstract Neutron physics is one of the oldest branches of the experimental nuclear physics,&#xD;but the investigation of the spontaneous neutron emission from the ground state along the neutron dripline is still at its beginning, in spite of the crucial importance for nuclear astrophysics. The proton dripline is much better investigated and a systematics of spontaneous proton half lives corected by the centrifugal barrier (monopole transitions) is given by the Geiger-Nuttall law $\log_{10}T\sim\chi$, &#xD;where $\chi\sim ZQ^{-1/2}$ is the Coulomb parameter characterizing the outgoing Coulomb-Hankel wave in terms of the daughter charge $Z$ and Q-value.&#xD;Our purpose is to propose a similar simple systematics of spontaneous neutron half lives, but in terms of the nuclear reduced radius $\rho=\kappa R\sim A^{1/3}Q^{1/2}$, characterizing the "neutral" outgoing spherical Hankel wave.&#xD;It turns out that the half life in emission of neutral particles is governed by the scaling law $T\sim\rho^{-2}\sim A^{-2/3}Q^{-1}$ for monopole transitions.&#xD;We evidence the important role of the angular momentum carried by the emitted neutron. The influence of the neutron wave function generated by a Woods-Saxon nuclear mean field is also analyzed.

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Bennike, O., & Funder, S. (1997). Macrofossil studies of Holocene lake sediments from Jameson Land, East Greenland. Geology of Greenland Survey Bulletin, 176, 80-83. https://doi.org/10.34194/ggub.v176.5070 _______________ Previous records of Holocene terrestrial and limnic environmental changes in East Greenland, mostly based on pollen analysis, have failed to extend beyond c. 9000 years BP (9 ka BP) because the lakes sampled were situated below the marine limit. The record obtained thus only goes back to the time when the lake basins became isolated from the sea (Funder, 1978; Björck et al., 1994; Funder & Hansen, 1996). In 1994, a lake near the coast of Jameson Land (Fig. 1) was cored with the aim of extending this record. This work was part of the ‘Arctic Terminations Project’, dealing with the timing and character of the last glacial maximum, the Flakkerhuk Stade, in the extensive Scoresby Sund fjord system (e.g. Hansen & Funder, 1995). By selecting a lake basin situated above the local marine limit and by applying macrofossil analysis instead of pollen analysis, the hope was that the sedimentary record could be extended further back in time and that far transported or reworked interglacial material could be avoided. Unfortunately, however, the minerogenic sediments were devoid of in situ organic remains, and thus could not be dated by radiometric methods; furthermore, the onset of organic sedimentation in this lake basin occurred later than in previously investigated lake basins at lower altitudes. In spite of these disappointing aspects, the results merit publication because they provide new evidence of post-glacial climate, environment and biogeography in the area and support the conclusions reached by pollen analysis.

In his fascinating book Die Zauberflöte, Oper und Mysterium (München-Wien, Carl Hanser Verlag, 2005; A varázsfuvola, opera és misztérium, Budapest, Atlantisz, 2012), Jan Assmann saw Mozart’s opera as a link between the Egyptian–Hellenistic mystery religions and the 18th-century Freemasonry and its legacy. According to his theory, Die Zauberflöte inherently contains an initiation ritual, which, in light of the Masonic interpretation of the mysteries, we can see as representing the ”lesser” and ”greater” stages of the masonic initiation. This study demonstrates that the musical intonation of the opera (the structure of tonalities, melody, harmony, rhythm and orchestration, etc.) leads finally even through three lines to the Nether World (Isis-Osiris/ Demeter-Persephone/ Orpheus-Euridice); yet in spite of all it may seem to be an absurd idea to connect Sarastro’s Empire with it. But the problem of rebirth in voluntary death-experience is not unfamiliar within Freemasonry, the intensive absorption in mortality is a part of their initiating processes. The ”secret” of Mozart’s ”masonic opera” is the summary of a mystical happiness got by insight into the last stage of masonic initiation.

Introduction and Background Sexual choking / strangulation encompasses a range of practices where pressure is applied to the neck to restrict air or blood flow during a sexual encounter. While choking is most commonly associated with the application of hands around a person’s neck, other limbs or ligatures, such as the forearm or rope, may also be used (Herbenick et al., Frequency 3122; Herbenick et al., Prevalence 1059). This article will predominantly use the term “choking” or “sexual choking” to match teen vernacular and public discourse. These terms, however, may be used interchangeably with other more context-specific terms used in the literature such as “breath play”, “strangulation”, “erotic asphyxiation”, and “sexual asphyxia” (Cardoso 1070; Vilhjálmsdóttir and Forberg 4). Recent studies exploring the prevalence of sexual choking (Sharman et al., Prevalence 1; Herbenick et al,. Prevalence 1068; Vilhjálmsdóttir and Forberg 24) indicate that sexual strangulation is a relatively common practice among young adults, including trans or gender-marginalised populations. In a recent Australian study, researchers found that 57% of participants (aged 18–35 years) reported being sexually strangled (from a sample of 4,702 adult Australians; Sharman et al., Prevalence 1). A US-based study of undergraduate and graduate students also found that choking during sexual encounters was consensual 92.1% of the time (Herbenick et al., Frequency 3130), indicating that choking can be a favoured and consensual activity between sexual partners. However, it is widely acknowledged and agreed upon that there is no adaptation of the practice that is entirely free from risk (Cardoso 1069; Schori et al 291); engaging in any form of the act can have harmful and potentially lethal consequences. The authors acknowledge that the devastating effects of sexual violence (including family and intimate partner violence (IPV) and sexual assault), which strangulation and non-fatal strangulation (NFS) form a part of, are a serious and significant issue (Bennett 167; White et al., 2); however, this article seeks to explore sexual choking practices within consensual contexts, given the rising prevalence of these behaviours. Pornography is often noted as the primary reason for the popularisation of sexual choking throughout modern discourse and existing research (Herbenick et al., Frequency 3135; Sharman et al., Prevalence 1). However, erotic asphyxiation and sexual hanging depictions are documented centuries earlier through renaissance paintings and prehistoric art such as Mayan relics (Tarr 57). In their study of 4,702 Australian adult participants (aged 18–35), Sharman and colleagues found that pornography was the most common way individuals reported first hearing about choking as a sexual activity (34.8%), whereas others discovered the concept via discussions with friends (11.5%; Prevalence 6). Other studies have identified shifts in sexual repertoire, such as choking, that may have been influenced by pornography (Herbenick et al., Diverse 624). However, much of public discourse is focussed on pornography’s influence without causal links. Nominal data taken from the Australian Research Council Project Adolescents’ Perceptions of Harm from Accessing Online Sexual Content which investigated teens' (aged 11–17 years) perceptions of pornography is explored in this article. Teens suggested that young people often mimic acts, such as sexual choking, that are depicted in pornography, and criticised pornography for not displaying safety parameters normally used in the BDSM/kink community. Some teens speculated that sexual choking may be a relatively common occurrence between young people. These teens suggest that there is a need for more accessible education and resources about risky sexual behaviours. This article explores teens’ perspectives of sexual choking through a sexological and public health lens and suggests that a broader harm reduction approach may result in better outcomes than an abstinence-only approach. This article may assist to inform public policy, public health strategies, and educational approaches. ‘Breath Play’ in BDSM/Kink The acronym BDSM stands for ‘bondage and discipline, dominance and submission, sadism and masochism’, can refer to a range of meanings and experiences, and often involves consensual power exchange, restraint, or intense sensations (Carlström 404; Lawrence and Love-Crowell 67; Schori et al. 293; Sprott 2). Breath play is an activity some may explore within BDSM/kink, and can include an array of activities that restrict airways or play with breath for sexual arousal (Sharman et al., Strangulation 1; Tomassilli et al., 439). BDSM has become popularised in recent years and is often misrepresented in the media, leading to pathologisation and misunderstanding of the practice (Ortmann and Sprott 34; Shahbaz and Chirinos 21). The BDSM/kink community prioritises safety as part of a “controlled set of practices governed by clear and identifiable cultural standards of behaviour” (Bennett 173). These practices require mutual consent to specific acts and refer to frameworks such as Safe, Sane, and Consensual (SSC), Risk-Aware Consensual Kink (RACK), and “safe words” (Bennet 164; Gewirtz-Meydan 584; Holt 928; Schori et al. 293), where safety is paramount. However, some of the most common injuries within the BDSM/kink community relate to breath play (a.k.a. “choking”; Sprott et al. 1723), including death (Schori et al. 295), and while informed BDSM practitioners are able to practice breath play in more aware and mindful ways, risk can never be fully eliminated (Holt 920; Schori et al. 291). Exploration through kink has been linked to healing and transformation of trauma, contributing to the development of a notion of healthy sexuality (Cascalheira et al. 373; Sprott 2). This exploration may provide a way to confront shame and explore desires and fantasies in a controlled, safe environment, which is compatible with a healthy, normal life (Lawrence and Love-Crowell 69; Gewirtz-Meydan, et al. 584; Sprott 4). Studies warn that in spite of concerns around the growing prevalence of sexual strangulation and choking, stigmatisation of kink-related activities is not conducive to improvements in public health for minority populations (Sharman et al. Prevalence 12; Herbernick et al., Frequency 3135). Shaming those who wish to engage in breath play and sexual choking (kink-shaming) is not advised, particularly given that this article explores that some teens may wish to engage in alternate sexual practices, potentially irrespective of the popularisation of such acts. Teen Perspectives A total of 49 interviews were carried out with 30 Australian teens aged 11–17 years; 30 were carried out in 2021–2022, with a further 19 interviews undertaken with the same teens at least one year later (2023). This research focussed on teen perspectives of pornography, and participants were predominantly recruited through social media. Permission was first sought via a parent who also agreed to an interview, as per the project’s ethics approval, and both parents and teens were given a small gift to thank them for their time. While discussing the impact of pornography, some teens instigated discussions around what they referred to as “choking”. Sexual choking was not the focus of the pornography study, and while the findings discussed were incidental, the organic discussions provide nominal insights into teens’ perspectives of sexual choking behaviours. One big danger with pornography is people start watching it and then they’ll start on the soft porn, and they’ll go from this into the next and that’s how they end up at BDSM. They’ll go to a partner and the partner’s also been watching it, but one of them doesn’t know about ‘aftercare’ [and] how to go and take care of the partner, or any of that sort of stuff, and while it starts well and they’ll have a hoot of a time, they don’t know proper limits, so they don’t know. For instance, if it’s choking, how to actually choke, because [if] you do it wrong, it’s not good. (Miles, 16) Miles illustrates a level of digital sexual literacy and awareness by utilising terms such as “aftercare”, a kink-specific terminology, which involves the checking-in and care of a sexual partner following a sexual encounter or “scene” (Fuentes 3). Miles used podcasts and social media to supplement his sexual knowledge, as he felt schools were not providing sufficient information, as is evident in other studies (Cardoso and Scarcelli 8). While most information sourcing for adults in BDSM and alternative sexual practices is done via self-directed means or social groups (Sprott, et al. 49), further availability of resources in non-formal environments could be useful to teens too. “Third-person media effects” may be evident in Miles’s reflection here, where individuals can perceive media to have a stronger influence on others than themselves (Perloff 357). Miles illustrates these effects while trying to make sense of his and his peers’ experiences. Miles speculates that pornography may inform young people’s sexual scripts, but often lack associated safety information that would normally accompany acts within the kink community. He believed the omission of safety information and relevant frameworks is where the harm lies. Similarly, Warren (17) stated: like if they’re watching hardcore stuff and they’re choking a girl, the girl might actually be getting suffocated by not doing it right, they could hurt the girl, like, a false idea of what it actually is. Warren recognised how the adoption of particular sexual scripts could be harmful when they occur without information to assist individuals to practise in safer ways. Given pornography has been explored as an influence for changes in sexual scripts and potentially contributes to popularising acts such as choking (Wright et al. 1100), these changes could be balanced with more available resources and education. In answer to whether resources could be of assistance, Warren answered: if there was a kink or something and they wanted to learn how to do that properly, it’d be good to have a video that they could actually learn. That’d be good. Teens recognised a gap, where more explicit educational resources could assist teens practicing risky behaviours, whether influenced by pornography or not, to engage in ways that can potentially reduce harm. The danger of teens potentially mimicking acts without being educated or informed about safety parameters, was further explored by Miles (16): in my cohort, [sexual choking is] seen as something that’s a bit risky, but a bit cool, and the girls are into [it] – but don’t really know [how], so there’s a lot of lines that are crossed because they don’t know how to set them up or while there might be safe words, they might not actually know how to [implement them] and have only seen porn where the safety borderlines are set beforehand, all you see is the porn. Miles reflected that safety practices such as “safe words”, or prior discussions of consent are seldom depicted in mainstream pornography. “Safe words” are a previously agreed-upon word or gesture which communicates to a partner the need to immediately cease a sexual activity (Weiss 78). Although borrowed from BDSM/kink, these frameworks could be considered as part of mainstream communication and harm-minimisation strategies (Herbernick et al., Frequency 3134) and could also be adopted as part of wider sexuality education skill development. It must also be considered that teens may perceive choking to be a risky, “cool” sexual practice and thus may feel peer pressured to engage. Indeed, existing research (Sharman et al. Strangulation) posits that “wanting” to engage in choking behaviours may reflect social conditioning (11), much like other sexual behaviours. Seraphina (12) shared that most young people she knew had seen pornography: “even girls watch that stuff [pornography] as well, like, with girls doing it, like, pretty much everyone has watched it or has come across it”. She implies that pornography viewing is widespread among teens, where some teens may be inspired by acts depicted in porn. Given choking was perceived as “cool” or “risky”, some teens may perceive expectation and/or pressure to engage in sexual choking, whereas some teens may genuinely desire to engage in these acts. These findings suggest that teens could benefit from education which encourages them to introspect and reflect upon whether they genuinely wish to engage in sexual acts or whether they feel socially pressured to do so. Most teens claimed that they were able to discern that porn is a fantasy and not very representative of reality; “you probably have to also keep in mind if you are looking at that sort of stuff, that it’s staged or fake or whatever and that that’s not realistic necessarily” (Heath, 14). Despite this, some young people believed their peers had a tendency to mimic what they had seen online: yes, it can be harmful for a load of people mainly because some dumb men might see a video and try to do it [pornographic acts] to a woman. (David, 11) A lot of people copy what they see online in general anyway, especially with the TikTok trends and everything so I reckon that people would copy things online. But I think it’s still pretty bad, I'm not sure why you’d want to copy things like that [acts in pornography], I mean sometimes I can understand TikTok trends but I think that’s on a different level and it’s just pretty bad. (Lauren, 13) These findings are supported by existing research (Rothman et al. 743; Smith 71), which found that young people often imitate what they see in pornography. Teens believe their peers can be quite impressionable, particularly in the digital age, and may be primed to copying behaviours online. Arguably, media literacy, including pornography literacy, could assist in encouraging teens to be aware of risk and to be more critical of the content they consume. Given the prevalence of choking behaviours among young people, educational programs and relevant messaging could consider discussing alternate sexual practices and how to engage in safer ways (Herbernick et al., Frequency 3133; Wright et al. 1105), particularly given that the predominant message that young people receive is to abstain, yet behaviours persist. Harm Reduction While it is widely acknowledged that there is no “risk-free” way to engage in choking behaviours (Cardoso 1069; Schori et al. 291), there is a need to acknowledge that there are some that will continue to practice or experiment with these behaviours. In the same way that a “zero tolerance” attitude around illicit substances and other sexual practices impedes help-seeking behaviours, acts as a barrier to education and information, and drives these behaviours underground, so too will an abstinence-only approach to sexual choking. Many authors have written about the dangers and ineffectiveness of abstinence-only sex education programs (particularly in the United States; Heals; LeClair; Santelli Abstinence; Santelli Abstinence-Only; and others), but there is also a significant amount of literature available relating to sex work, HIV/AIDS, chem-sex, and other high-risk sexual behaviours highlighting that “abolition is not effective in reducing those harms and indeed may, in fact, exacerbate them” (Dea 340). Harm reduction is an important yet controversial strategy that provides an “alternative to the moral/criminal” approaches in public health (Dea 302–4). While abstinence is the ideal goal, harm reduction seeks to reduce the harm associated with stigmatised behaviours through a larger, nested approach that allow experts and governments to acknowledge that these behaviours occur within society, without supporting the risky behaviour (Hickle 302; Wellbourne-Wood 407). This approach takes a morally neutral stance which shifts the emphasis to health and human rights, and acknowledges that social approaches are a more suitable and more effective approach (Denis-Lalonde 321; Hawk et al. 4; Hickle 302; Keane 228; Steenholdt and Colquhoun 12). Harm reduction incorporates a range of strategies, including education, information provision, prevention, care guides, and first aid training, along with policy, legislative, and punitive measures (Dea 305; Denis-Lalonde 318; Hawk 2). To reduce harm to individuals who may engage in sexually risky behaviours, experts must navigate barriers such as stigma, marginalisation, or lack of awareness (Sansone et al. 3). The criminalisation of sex work, for instance, can result in increased risk and harms, as sex workers may be afraid to seek help when they are in danger (Dea 305). Harm reduction interventions, on the other hand, link vulnerable and marginalised individuals with experts capable of providing necessary assistance, information, and education (Hickle 302). The criminalisation of risky sexual behaviours alone places clinicians, sexual health practitioners, and those seeking help, assistance, or information, in a problematic position (Piatkowski et al. 62). When faced with an individual seeking assistance, the practitioner must decide whether to aid in the minimisation of potential harms or follow legally sanctioned procedures (referral to domestic family violence services or police referral; Victoire 875). On the other hand, individuals face challenges in seeking help and support due to the stigma and fear associated with the illegal nature of these health behaviours (Piatkowski et al. 62; Stangl et al. 1). As Treloar states: “it’s really hard to step up and identify with living with a stigmatised condition or identity or practice. For someone who’s prohibited [criminalised] on top of that, the fear of repercussions is even greater” (Treloar in Australian Academy of Science). Stigma, discrimination, and marginalisation of individuals who engage in alternative sexual practices, by both medical professionals and others, is widespread (Bezreh et al.; Hansen-Brown et al.; and others). In order to seek help, an individual needs to feel confident that they will not face criminal sanctions from the police, nor will they be subject to stigma or marginalisation from society (Sansone et al. 7). Conclusion There is little published evidence on how teens perceive sexual choking and strangulation practices. This article offers nominal insight into teens' perspectives of choking depicted in pornography, and speculates on the prevalence of the practice among their peers. Like adults, teens indicated that many young people (of all genders) share an inclination to partake in alternative sexual practices such as “choking”. Participants also recognised that their peers were uneducated in terms of “safer” alternative practices, often learning BDSM/kink-inspired acts from pornography. However, young people felt that pornography could be misleading, given that safety parameters normally implemented in the kink scene were not often displayed on screen, leaving room for potentially dangerous consequences. Some teens suggested that resources and educational information could assist them to navigate these practices in safer ways. More adolescent-focussed research with a greater sample size is needed, with research questions more specifically aligned with the prevalence of sexual strangulation and teens’ interpretation of these risky sexual behaviours, particularly given the limitations of this study sample. The authors note that this article neither advocates nor condones these behaviours. 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