Simple Form Research Articles

Marine propulsion shafting-oriented status detection algorithm for uncertainty time-varying

The marine propulsion shafting is the lifeline of navigation. The marine propulsion shafting vibration signals tend to contain rich connotations that suggest the shafting status. In this paper, aiming at the difficulty in the capture of time dependence in uncertainty time-varying signals of marine propulsion shafting, the concept of Degree of Membership (DM) in fuzzy mathematics is introduced into Recurrent Neural Network (RNN), called Degree of Membership Recurrent Neural Network (DM-RNN). A marine propulsion shafting status detection algorithm based on DM-RNN is proposed. Specifically, the mathematical expressions for forward propagation and back propagation of DM-RNN are theoretically derived. The self-propulsion test scheme based on a full-scale boat is designed. Actual vibration signals under multiple working conditions are collected. The progressiveness of the present algorithm under shafting vibration signals of the full-scale boat is verified by the experiment. The results of the two comparison experiments indicate that the present algorithm significantly improved the detection accuracy compared with the classical ANNs, up to 93.25% ± 0.71%. Furthermore, a DM function with a simple form and fewer parameters was more conducive to the high detection accuracy of DM-RNN.

On the Vertical Libration of Maxwell’s Ring Configuration with a Manev Potential

We discuss Maxwell’s ring model with a quasi-homogeneous potential of the dominant mass, and specially study the vertical libration of Maxwell’s ring configuration with a Manev potential. There are two kinds of periodic vertical libration, which are non-alternating and alternating cases. The Hamiltonian is highly symmetric and can be reduced to a simple form with two degrees of freedom. Then the Hamiltonian is expanded near the planar circular relative equilibria. By the Lie transformation technique, the birkhoff norm form up to the fourth order is calculated. When the mass ratio between the ring and the dominant mass, and the coefficient of the second term in a Manev potential are both small enough, the nonlinear stability for the vertical libration of Maxwell’s ring configuration with a Manev potential is then proved according to Arnold’s stability theorem.

Sustainable humification of food waste slurry through thermally activated persulfate oxidation

This study introduces a thermoanalytical approach utilizing sodium persulfate (PS) to expedite the humification of food waste (FW) through advanced oxidation processes (AOPs). The method harnesses heat-induced free radicals to break down complex organic compounds into simpler forms, leading to the formation of humic substances. We conducted an analysis of changes in soluble chemical oxygen demand (SCOD), dissolved organic carbon (DOC), ammonia nitrogen, soluble proteins, and sugars, employing advanced techniques such as three-dimensional fluorescence spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM). The findings indicate that the activation of PS at 70°C effectively increases SCOD and DOC levels, converts proteins into soluble forms, and enhances NH4+-N content. This study, which focuses on the utilization of thermal methods, affirms that the thermal activation of persulfate (PS) significantly boosts the humification of food waste (FW), presenting a sustainable approach for waste management and resource recovery.

Polymetallic red mud direct materialization strategy towards zero waste emission: Electromagnetic wave absorption conversion and sodium solidification

Red mud is an industrial hazardous alkaline solid waste, whereas it is rich in polymetallic components showing a high comprehensive utilization value. Direct materialization of red mud towards zero waste emission is a more reasonable and environmentally friendly strategy. In this work, a novel materialization approach of red mud via converting the polymetallic constituents into functional ferrite material by phase reconstruction with MnO2 was proposed. The mineral phase reconstruction, microstructure evolution, reaction interface observation, electromagnetic property, and the materialization conversion mechanism were investigated. It was found that the complicated phases in red mud were transferred to simple forms including the magnetic ferrites (Ca/Na/Al/Ti-bearing Mn ferrite) and weakly magnetic silicates ((Na,Al,Ca)2SiO3) after phase reconstruction. The reconstructed red mud after sintering at 1200 ℃ for 120min in air atmosphere had satisfactory electromagnetic property. Magnetism study demonstrated the soft magnetic property with maximum saturation magnetization of 34.22emu/g and coercivity of only 7.0Oe. Compared with the original red mud, effective electromagnetic wave absorption with reflection loss (RL) values of the reconstructed red mud below -20 dB were satisfied across a wider frequency bandwidth of 5-18GHz, and the minimum RL value was lower as -32.4dB with a thinner veneer thickness of 15mm, highlighting its excellent electromagnetic wave absorption performance. Moreover, Na solidification behaviors indicated that Na was solidified in the sintered product, which can reduce the possible environmental hazards of red mud alkalinity. The novel materialization treatment with zero waste emission exhibits a favorable application prospect with a large red mud batching ratio about 50wt%.

Stability scrutinization of a non‐Newtonian (Williamson) ternary hybrid nanofluid past a stretching/shrinking sheet

AbstractThe thermal superiority of ternary hybrid nanofluids (THNFs) over conventional heat transfer fluid has led to growing interest in their applications. This new type of nanofluid can be customized for cooling systems, heat exchangers, and electronic cooling by carefully selecting nanoparticle types and their volume fraction. Hence, this study seeks to investigate the Heimenz flow in a Williamson THNF over a sheet that stretches or shrinks. The fundamental objective is to assess the effect of the stretching/shrinking parameter, the Weissenberg number, and the nanoparticle volume fraction on the physical quantities and flow profiles. Besides, attention is also given to the occurrences of multiple solutions in this fluid flow situation. By employing a similarity transformation, the governing equations are modified as a simpler form of ordinary differential equations (ODEs). Next, the numerical method is put to use to solve the resulting ODEs system, specifically the bvp4c solver in MATLAB. Significant changes in heat transmission occur due to variations in the Weissenberg number and volume fractions of nanoparticles, particularly when the sheet starts to shrink. The escalating Weissenberg number correlates with growing critical values of the stretching/shrinking parameter, suggesting that both parameters help to hold off the detachment of the boundary layer. These findings emphasize the capacity of THNFs to improve heat transfer performance in numerous applications. This study also reveals that while stretching sheets often have unique solutions, a shrinking sheet has multiple solutions when the shrinking parameter falls within a certain range. By scrutinizing the robustness of these solutions, it was concluded that only one of them maintains stability over an extended period. It is essential to highlight that these present discoveries apply exclusively to the mixture of copper, alumina, and titania. Various mixtures of nanoparticles can demonstrate distinct characteristics of THNFs concerning both flow dynamics and thermal transfer.

Multi-strategy based quantum cost reduction of quantum boolean circuits

Abstract The construction of quantum computers is based on the synthesis of low-cost quantum circuits. The quantum circuit of any Boolean function expressed in a Positive Polarity Reed-Muller (PPRM) expansion can be synthesized using Multiple-Control Toffoli (MCT) gates.
This paper proposes two algorithms to construct a quantum circuit for any Boolean function expressed in a PPRM expansion. The Boolean function can be expressed with various algebraic forms, so there are different quantum circuits can be synthesized for the Boolean function based on its algebraic form. The proposed algorithms aim to map the MCT gates into the NCV gates for any quantum circuit by generating a simple algebraic form for the Boolean function. The first algorithm generates a special algebraic form for any Boolean function by rearrangement of terms of the Boolean function according to a prede fined degree of term dterm, then synthesizes the corresponding quantum circuit. The second algorithm applies the decomposition methods to decompose MCT circuit into its elementary gates followed by applying a set of simplification rules to simplify and optimize the synthesized quantum circuit. The proposed algorithms achieve a reduction in the quantum cost of synthesized quantum circuits when compared with relevant work in the literature. The proposed algorithms synthesize quantum circuits that can applied on IBM quantum computer.

Diacylglycerol metabolism and homeostasis in fungal physiology.

Diacylglycerol (DAG) is a relatively simple and primitive form of lipid, which does not possess a phospholipid headgroup. Being a central metabolite of the lipid metabolism network, DAGs are omnipresent in all life forms. While the role of DAG has been established in membrane and storage lipid biogenesis, it can impart crucial physiological functions including membrane shapeshifting, regulation of membrane protein activity and transduction of cellular signalling as a lipid-based secondary messenger. Besides, the chemical diversity of DAGs, due to fatty acyl chain composition, has been proposed to be the basis of its functional diversity. Therefore, cells must regulate DAG level at a spatio-temporal scale for homeostasis and adaptation. The vast network of eukaryotic lipid metabolism has been unravelled majorly by studying yeast models. Here, we review the current understanding and the emerging concepts in metabolic and functional aspects of DAG regulation in yeast. The implications can be extended to understand pathogenic fungi and mammalian counterparts as well as disease aetiology.

Benefiting from binary negations? Verbal negations decrease visual attention and balance its distribution

Negated statements require more processing efforts than assertions. However, in certain contexts, repeating negations undergo adaptation, which over time mitigates the effort. Here, we ask whether negations hamper visual processing and whether consecutive repetitions mitigate its influence. We assessed the overall attentional capacity, that is, the available processing resources, and its distribution, the relative weight, quantitatively using the formal Theory of Visual Attention (TVA). We employed a very simple form for negations, binary negations on top of an accuracy-based, TVA-based temporal-order judgment (TOJ) paradigm. Negated instructions, expressing the only alternative to the core supposition, were cognitively demanding, resulting in a loss of attentional capacity in three experiments. The overall attentional capacity recovered gradually but stagnated at a lower level than with assertions, even after many repetitions. Additionally, negations distributed the attention equally between the target and reference stimulus. Repetitions slightly increased the reference stimulus' share of attention. Assertions, on the other hand, shifted the attentional weight toward the target stimulus. Few repetitions slightly decreased the attentional shift toward the target stimulus, many repetitions increased it.

A Mathematical Model for Collective Behaviors and Emergent Patterns Driven by Multiple Distinct Stimuli Produced by Multiple Species

Collective migration underlies key developmental and disease processes in vertebrates. Mathematical models describing collective migration can shed light on emergent patterns arising from simple mechanisms. In this paper, a mathematical model for collective migration is given for arbitrary numbers and types of individuals using principles outlined as a set of assumptions, such as the assumed preference for individuals to be “close but not too close" to others. The model is then specified to the case of two species with arbitrary numbers of individuals in each species. A particular form of signal response is used that may be parameterized based on experiments involving two or three agents. In its simplest form, the model describes two species of individuals that emit distinct signals, distinguishes between them, and exhibits responses unique to the type by moving according to signal gradients in various planar regions, a situation described as "mixotaxis". Beyond this simple form, initial conditions and boundary conditions are altered to simulate specific, additional in vitro as well as in vivo dynamics. The behaviors that were specifically accounted for include motility, directed migration, and a functional response to a signal. Ultimately, the paper’s results highlight the ability of a single framework for signal and response to account for patterns seen in multi-species systems, in particular the emergent self-organization seen in the embryonic development of placodal cells, which display chase-and-run behavior, flocking behavior, herding behavior, and the splitting of a herd, depending on initial conditions. Numerical experiments focus around the primary example of neural crest and placodal cell “chase-and-run” and “flocking” behaviors; the model reproduces the separation of placodal cells into distinct clumps, as described in the literature for neural crest and placodal cell development. This model was developed to describe a heterogeneous environment and can be expanded to capture other biological systems with one or more distinct species.

Resolving turbulence and drag over textured surfaces using texture-less simulations: the case of slip/no-slip textures

We study the effect of surface texture on an overlying turbulent flow for the case of textures made of an alternating slip/no-slip pattern, a common model for superhydrophobic surfaces, but also a particularly simple form of texture. For texture sizes $L^+ \gtrsim 25$ , we have previously reported that, even though the texture effectively imposes homogeneous slip boundary conditions on the overlying, background turbulence, this is not its sole effect. The effective conditions only produce an origin offset on the background turbulence, which remains otherwise smooth-wall-like. For actual textures, however, as their size increases from $L^+ \gtrsim 25$ the flow progressively departs from this smooth-wall-like regime, resulting in additional shear Reynolds stress and increased drag, in a non-homogeneous fashion that could not be reproduced by the effective boundary conditions. This paper focuses on the underlying physical mechanism of this phenomenon. We argue that it is caused by the nonlinear interaction of the texture-coherent flow, directly induced by the surface topology, and the background turbulence, as it acts directly on the latter and alters it. This does not occur at the boundary where effective conditions are imposed, but within the overlying flow itself, where the interaction acts as a forcing on the governing equations of the background turbulence, and takes the form of cross-advective terms between the latter and the texture-coherent flow. We show this by conducting simulations where we remove the texture and introduce additional, forcing terms in the Navier–Stokes equations, in addition to the equivalent homogeneous slip boundary conditions. The forcing terms capture the effect of the nonlinear interaction on the background turbulence without the need to resolve the surface texture. We show that, when the forcing terms are derived accounting for the amplitude modulation of the texture-coherent flow by the background turbulence, they quantitatively capture the changes in the flow up to texture sizes $L^+ \approx 70{-}100$ . This includes not just the roughness function but also the changes in the flow statistics and structure.

The constraint tensor for null hypersurfaces

In this work we provide a definition of the constraint tensor of a null hypersurface data which is completely explicit in the extrinsic geometry of the hypersurface. The definition is fully covariant and applies for any topology of the hypersurface. For data embedded in a spacetime, the constraint tensor coincides with the pull-back of the ambient Ricci tensor. As applications of the results, we find three geometric quantities on any transverse submanifold S of the data with remarkably simple gauge behaviour, and prove that the restriction of the constraint tensor to S takes a very simple form in terms of them. We also obtain an identity that generalizes the standard near horizon equation of isolated horizons to totally geodesic null hypersurfaces with any topology. Finally, we prove that when a null hypersurface has product topology, its extrinsic curvature can be uniquely reconstructed from the constraint tensor plus suitable initial data on a cross-section.

Touch-down condition control for the bipedal spring-mass model in walking.

Behaviors of animal bipedal locomotion can be described, in a simplified form, by the bipedal spring-mass model. The model provides predictive power, and helps us understand this complex dynamical behavior. 
In this paper, we analyzed a range of gaits generated by the bipedal spring-mass model during walking, and proposed a stabilizing touch-down condition for the swing leg. This policy is stabilizing against disturbances inside and outside the same energy level and requires only internal state information. In order to generalize the results to be independent of size and dimension of the system, we nondimensionalized the equations of motion for the bipedal spring-mass model. We presented the equilibrium gaits (a.k.a fixed point gaits) as a continuum on the walking state space showing how the different types of these gaits evolve and where they are located in the state space. Then, we showed the stability analysis of the proposed touch-down control policy for different energy levels and leg stiffness values. The results showed that the proposed touch-down control policy can stabilize towards all types of the symmetric equilibrium gaits. Moreover, we presented how the peak leg force change within an energy level and as it changes due to the type of the gait; peak force is important as a measurement of injury or damage risk on a robot or animal. Finally, we presented simulations of the bipedal spring-mass model walking on level ground and rough terrain transitioning between different equilibrium gaits as the energy level of the system changes with respect to the ground height. The analysis in this paper is theoretical, and thus applicable to further our understanding of animal bipedal locomotion and the design and control of robotic systems like ATRIAS, Cassie, and Digit.

Study on the Liquid‐Holding Rate Law of Gas–Water–Foam Three‐Phase Flow in a Wavy Pipe

ABSTRACTAs a common method for liquid drainage in wave‐shaped pipelines, foam drainage has been used in gas‐gathering pipelines in various oil and gas fields. One of the common problems encountered in wave‐shaped foam drainage pipelines is the inaccurate prediction of the liquid retention rate. This issue makes it difficult to predict liquid accumulation points, which affects gas output efficiency, causes pipeline corrosion, and generates natural gas hydrates. To clarify the liquid‐holding rate law of wavy foam drainage pipelines is studied. In this study, through experiments to verify the accuracy of the numerical simulation method, we investigate the easiest liquid accumulation points and the liquid‐holding rate of wave‐shaped foam drainage pipelines, with factors such as inlet gas velocity, inlet liquid velocity, import and export differential pressure, undulation angle, and inlet temperature change rule. Among them, the error between the numerical simulation results and the experimental results is 4.68%. Finally, after considering the influence of the aforementioned factors on the liquid retention rate of wave‐shaped pipelines, a new liquid retention rate calculation model for wave‐shaped pipelines with foam drainage is established by introducing dimensionless numbers, such as gas‐phase velocity coefficient, liquid‐phase velocity coefficient, and angle correction coefficient. The method is compared with the results of previous research, and the error is within 15%. The model has a simple form and high calculation accuracy, providing a theoretical basis for pipeline inspectors to predict liquid accumulation conditions and reasonably adjust production schedules.

Genetic parameter estimation for traits related to the immune system against sheep red blood cells in Japanese quail

ABSTRACT 1. Improving resistance against disease is important in the animal and poultry industry. Besides drugs and vaccines, genetic selection for improved immune systems may be an effective approach. 2. Traits related to the immune system were studied in a 938 pedigreed Japanese quail population infected by sheep red blood cells (SRBC). Besides body weight at 35 d of age (BW35), weight of the gizzard (G), liver (Li), lungs (Lu), bursa (Bu), spleen (S), heart (H), and digestive track (D) and length of ileum (I) and caecum (C) were recorded. Total antibody (TA), mercaptoethanol-resistant (IgG), mercaptoethanol-sensitive titres (IgM), the number of monocyte (M), basophil (B) and eosinophil (E) and the ratio of heterophil to lymphocyte (H/L) were measured. Co-variance components were estimated via Gibbs sampling using GIBBS3F90 software. Five univariate animal models, including simple forms, were used for genetic parameter estimations, and the best model was determined by the deviance information criterion (DIC). Genetic and environmental correlations were estimated using a bivariate animal model. 3. Direct heritability estimates for internal organs ranged from 0.06 (Lu) to 0.57 (G) and for immune system traits from 0.05 (IgM) to 0.17 (IgG). Negative genetic correlations were found between BW35 and internal organs (−0.22 to −0.80). 4. Including one of the internal organs, such as the spleen, in the selection index improved the immune response in heavier birds. Additionally, because of the moderate heritability of IgG (0.17) and its effect on lasting immunity, selecting for higher IgG concentration may improve the resistance of Japanese quail against pathogens.

Quadratic Programming Problems and Its Solution Techniques With Neural Network Modeling

ABSTRACTThis paper presents a study on quadratic programming problems (QPP) and introduces a new neural network model with feasibility analysis. The stability analysis of QPP using neural network modeling is also discussed. The proposed neural network model has a simple form, and its optimal feasibility for both primal and dual QP problems is established. The model demonstrates a good convergence rate with a minimal number of iterations, achieving a very fast convergence to the exact solutions of both the primal and dual QP problems. The optimal solutions for the original QP problem and its dual QPP are obtained. Finally, two simple numerical examples are simulated to illustrate the findings.

Speed excess and total acceleration: a kinematical approach to entanglement

Abstract The total variance of a spin state is defined as the average of the variances of spin projection measurements along three orthogonal axes. We show that this quantity also gives the squared rotational speed of the state in projective space, averaged over all rotation axes. We compute the addition law, under system composition, for this quantity and find that, in the case of separable states, it is of simple pythagorean form. In the presence of entanglement, we find that the composite state ‘rotates faster than its parts’, thus unveiling a kinematical origin for the correlation of total variance with entanglement. We analyze a similar definition for the acceleration of a state under rotations, for both pure and mixed states, and probe numerically its relation with a wide array of entanglement related measures.

A momentum-conserving wake superposition method for wind-farm flows under pressure gradient

Pressure gradient over topography will significantly affect wind-farm flow. However, knowledge gaps still exist on how to superpose wind-turbine wakes in the wind-farm flow analytical model to account for this effect, leading to systematic errors in evaluating wind-farm wake effects. To this end, we derive an implicit momentum-conserving wake superposition method under pressure gradient (PG-IMCM) based on the total momentum deficit equation, which is linearised by the convection velocity introduced by Zong & Porté-Agel (J. Fluid Mech., vol. 889, 2020, A8). The PG-IMCM method consists of the linear-weighted sum of individual velocity deficits, the sum of the individual pressure correction terms and the total pressure correction term. Based on a sensitivity analysis, we demonstrate that the last two terms nearly cancel out and, thus, can be neglected, resulting in a simplified form, which has the same form as its counterpart under zero pressure gradient but with the single-wake quantities redefined based on the wake model under pressure gradient. This motivates us to further examine the performance of the combination of five empirical superposition methods and the stand-alone wake model under pressure gradient. Validation results based on large-eddy simulation show that PG-IMCM has an overall satisfactory performance in both the magnitude and shape of the velocity-deficit profiles, provided that the stand-alone turbine wake can be modelled accurately, which is virtually identical with its simplified form. Further comparison with empirical superposition methods shows that local linear and wind product superposition methods based on the updated base flow also have comparable performance, with only discernable differences with the PG-IMCM method in the near-wake region of downstream turbines. Therefore, they are two attractive methods for engineering applications.

21-Hydroxylase Deficiency Detected in Neonatal Screening: High Probability of False Negativity in Late Onset Form.

Despite the high sensitivity of neonatal screening in detecting the classical form of congenital adrenal hyperplasia due to 21-hydroxylase deficiency, one of the unclear issues is identifying asymptomatic children with late onset forms. The aim of this nationwide study was to analyse the association between genotype and screened level of 17-hydroxyprogesterone in patients with the late onset form of 21-hydroxylase deficiency and to quantify false negativity. In the Czech Republic, 1,866,129 neonates were screened (2006-2022). Among this cohort, 159 patients were confirmed to suffer from 21-hydroxylase deficiency, employing the 17-hydroxyprogesterone birthweight/gestational age-adjusted cut-off limits, and followed by the genetic confirmation. The screening prevalence was 1:11,737. Another 57 patients who were false negative in neonatal screening were added to this cohort based on later diagnosis by clinical suspicion. To our knowledge, such a huge nationwide cohort of false negative patients has not been documented before. Overall, 57 patients escaped from neonatal screening in the monitored period. All false negative patients had milder forms. Only one patient had simple virilising form and 56 patients had the late onset form. The probability of false negativity in the late onset form was 76.7%. The difference in 17-hydroxyprogesterone screening values was statistically significant (p<0.001) between severe forms (median 478.8 nmol/L) and milder (36.2 nmol/L) forms. Interestingly, the higher proportion of females with milder forms was statistically significant compared with the general population. A negative neonatal screening result does not exclude milder forms of 21-hydroxylase deficiency during the differential diagnostic procedure of children with precocious pseudopuberty.

Machine Learning: A survey of requirements prioritization: A Review Study

In any software systems, the requirements prioritization considered as pivotal task. This paper aims to explain and discuss the works done on requirements prioritization based Machine learning along with the dependency-aware requirements prioritization. Machine learning has become of attention to scientists, researchers, and users because of the existence of vast data and deep learning algorithms that can analyze massive sets of data. The basic algorithms are used for dependency learning calculation, resolve the stakeholder’s conflicts, classify requirements, and scalability improvement. This paper will present a brief background and comprehensive presentation of a number of machine learning techniques for requirements prioritization and those concerning the requirement dependency in its simple, complex, and Hybrid form. There are a number of papers, articles, and research papers that deal with requirements prioritization, few of them handling the dependency. This paper will present a brief background for several requirements prioritization based on machine learning. then make a comparison and discussion of a number of selected techniques in terms of algorithm type, issues addressed, and evaluated data level. method that handling the dependency regarding of strengths and weakness.

Schaár Erzsébet ifjúkora és korai szobrászművészete (1908-1931)

The present paper is a subchapter of my doctoral dissertation titled The Oeuvre of Sculptor Erzsébet Schaár (1908– 1975). The paper discussing a period of her life’s path sofar only tangentially touched on by special literature divides into three parts: the first is concerned with the artist’s family background, childhood and adolescence, the second with the initial phase of the career, the academy years, and the third looks at works created in the 1920s and the early 1930s, as well as exhibitions of that period.Schaár was a veritable “child prodigy”. She began her studies as Zsigmond Kisfaludi Stróbl’s private pupil at the age of sixteen and a year later, in 1925 she was admitted to the Royal Academy of Art where her tutor was again Kisfaludi Stróbl. She debuted with her works publicly in 1926, first of all in exhibitions of the Szinyei Society and the KÚT (=new society of artists). Though several of her that-time works got lost or are latent, an approximately authentic overview of her art in that period can be had from exhibition catalogues, receptions, materials in archives and private collections – first of all the Vilt estate in the King St Stephen Museum in Székesfehérvár and the mostly unprocessed written and photography documents, correspondence in the Schaár estate, as well as from recollections by her contemporaries, first of all Tibor Vilt. A few nudes are known from this period, but her early artistic activity centred on portrait sculpture. This is also the clew along which the phases Schar’s artistic development, the modifications of her style, the influences exerted on her can be demonstrated from the earliest known portraits of her mother to the series of children’s portraits in the late 1920s, early 1930s. The studied period is characterized by a search of her own idiosyncratic style: in the 1920s she created both realistic portraits and works displaying features of art deco and cubism, she was interested in modelling with simple forms, experimented with facial casts – a procedure that returned in later phases of the oeuvre.In sum, the earliest period of Schaár’s sculptural activity displays such singularly powerful idea of plasticity and creative outlook that compare with the later phases of the oeuvre in talent and quality, but with the help of which posterity can discern the trends that were to unfold in full later. Studying this early period may contribute to a more profound understanding and comprehensive interpretation of the entire oeuvre.