Core Piece Research Articles

Numerical Simulation and Experiment on Excavating Resistance of an Electric Cable Shovel Based on EDEM-RecurDyn Bidirectional Coupling

The electric cable shovel (ECS) is one of the core pieces of equipment used in open-pit mining, and the prediction of its excavating resistance is the basis and focus of optimization design, such as excavation trajectory planning and structure optimization of the ECS. Aiming to predict the excavating resistance of an ECS, a computer simulation method for the excavating resistance based on EDEM-RecurDyn bidirectional coupling simulation is proposed herein. Taking the China-made WK series ECS as the research object, a 1/30 scale model of the ECS was set up, a prototype model test bench of the ECS was built, and the kinematics solution and force analysis of the excavating process were carried out. According to the actual excavation conditions and excavating process of the ECS, a discrete element model of the material stack and a multibody dynamics model of the ECS prototype were established. The EDEM-RecurDyn bidirectional coupling simulation of the excavating process were realized using interface technology, and the excavating resistance levels under different speed combinations and different material repose angles were simulated and analyzed. In order to verify the accuracy of the simulation results, the feasibility and reliability of the EDEM-RecurDyn bidirectional coupling simulation were verified by physical experiments. The results show that the simulated excavating resistance is basically consistent with the excavating resistance measured in the experiment in terms of peak value and change trend, which verifies the feasibility and reliability of the EDEM-RecurDyn bidirectional coupling simulation to study the excavating resistance of an ECS.

The Logic of the Body: Retrieving Theological Psychology

The Logic of the Body: Retrieving Theological Psychology

“Am I Going to Die?”: Delivering Serious News to Patients With Liver Disease

“Am I Going to Die?”: Delivering Serious News to Patients With Liver Disease

Effect of the maximum thickness of a composite airfoil on the performance of a helical axial-flow gas-liquid multiphase pump

Operating efficiency and reliability are major problems that restrict gas-liquid multiphase pumps, which are core pieces of equipment used in deep-sea oil and gas exploration and transportation. In this paper, a 100-20x helical axial-flow gas-liquid pump is taken as the research object. The Euler multiphase flow model and SST k-ω turbulent model are used to model the multiphase pump. By exploring the airfoil composite position and the maximum thickness composite scheme, a mathematical model for the head coefficient and efficiency of the multiphase pump with respect to the relative thickness is established, and the external and internal flow characteristics of the modified multiphase pump are analyzed. We explore the influence of the composite position and the maximum thickness variation law of the composite airfoil on the performance of the mixed pump and determine the final airfoil composite scheme. We found that a change in the maximum thickness of the composite airfoil gives the external curve of the multiphase pump a “hump"-like characteristic, which shows that the head coefficient and efficiency increase first and then decrease with the increase in the maximum thickness of the composite airfoil. When the composite position is in the middle of the airfoil, the airfoil maximum thickness is 1.25 mm and the gas-phase volume fraction is 70%. Moreover, the head coefficient and efficiency of the multiphase pump reach their maximum values; the head coefficient and efficiency increase by 2.4% and 1.16%, respectively, compared with the basic model.

Strength reduction of foam-core sandwich structures with core mismatches

Discontinuities in foam-core composite sandwich panels are challenging to assess, in part due to shortcomings in the fundamental understanding of failure processes occurring in the foam. Extensive testing and analysis are frequently required to overcome this lack of understanding when evaluating large-scale structures. This integrated experimental and analytical study investigates the effect of core thickness mismatches on the load carrying capabilities of composite sandwich structures. These mismatches are commonly found in large composite components in aerospace, marine, automotive and other industries and can cause major reductions in sandwich shear strength. Mismatches result from joints between separate pieces of foam core within the sandwich, becoming potential failure initiation sites. Quantifying the reduction in shear strength is difficult due to the complex interaction between the facesheets, butt-joints and core. Sandwich structures containing butt joints are investigated through a research effort that included fabrication, testing, analysis, and nondestructive evaluations. The strength reduction of sandwich beams due to the presence of butt joints is quantified via three-point bend (3PTB) testing for various types of mismatches such as height and thickness of the butt joint. Key mechanical properties of the foam and the lamina are measured through testing and incorporated into analytical models. A stress area approach is proposed as a failure criterion, as test results show this to be promising in predicting the strength reductions measured in the 3PTB testing and the failure initiation site.

The Disruptive Physician and Our Role as Teachers.

The Disruptive Physician and Our Role as Teachers.

Magnetization of ferromagnetic charge at induction heating

The article presents analysis of magnetization and heating of ferromagnetic charge in crucibles of induction furnaces of two types. In inductor furnaces, the charge is magnetized by a vertical electromagnetic flow, and in electromagnetic furnaces with a curved U-, C-, or O-shaped magnetic circuit (MPr) – by a horizontal flow. Knowledge of these largely general magnetization processes is insufficient. Bi magnetic induction in charge material is rather important. There are difficulties in determining this parameter during magnetization of a single piece of charge and other magnetic quantities associated with it: Bm induction and Nm strength of the demagnetizing field, N demagnetization coefficient, M magnetization, magnetic permeabilities of μi substance and μt body, km susceptibility, etc. Difficulties increase at magnetization, if it is a porous body with crucible volume of ~V t and a factor of filling with ferromagnetic pieces of this volume of Kv ≤ 0.5. It also creates a demagnetizing field with Bmt induction and Hmt strength. Beyond that, pores have an additional demagnetizing effect. Therefore, the induction Вiт in a porous body is less than the induction Вi in a solid one. To compare magnetization of ferromagnetic charge with horizontal and vertical flows with frequency of 50 Hz, modeling experiments were carried out with the samples of DSL08 unconsolidated shot from high-carbon steel (GOST 11964 – 83) with Kv ≈ 0.53. The samples were placed in the inductor and between the poles of a U-shaped core piece. Induction was measured by a cylindrical and flat probe unit of Sh1-15 militeslameter in air and in the sample. An advantage of electromagnetic furnace over an inductor one is more uniform distribution of Bi induction in charge and its significant excess (1.7 times) over the Be induction in a furnace working cavity, which indicates more efficient use of electromagnetic energy in this furnace during heating. The author proposed to control Вi induction when heating the charge by the ammeter-voltmeter method using measuring coil made of heat-resistant wire.

A low-cost 3D-printable differential scanning fluorometer for protein and RNA melting experiments

Differential scanning fluorimetry (DSF) is a widely used biophysical technique with applications to drug discovery and protein biochemistry. DSF experiments are commonly performed in commercial real-time polymerase chain reaction (qPCR) thermal cyclers or nanoDSF instruments. Here, we report the construction, validation, and example applications of an open-source DSF system for 176€, which, in addition to protein-DSF experiments, also proved to be a versatile biophysical instrument for less conventional RNA-DSF experiments. Using 3D-printed parts made of polyoxymethylene, we were able to fabricate a thermostable machine chassis for protein-melting experiments. The combination of blue high-power LEDs as the light source and stage light foil as filter components was proven to be a reliable and affordable alternative to conventional optics equipment for the detection of SYPRO Orange or Sybr Gold fluorescence. The ESP32 microcontroller is the core piece of this openDSF instrument, while the in-built I2S interface was found to be a powerful analog-to-digital converter for fast acquisition of fluorescence and temperature data. Airflow heating and inline temperature control by thermistors enabled high-accuracy temperature management in PCR tubes (±0.1 °C) allowing us to perform high-resolution thermal shift assays (TSA) from exemplary biological applications.

Fostering Autonomy and Self Determination in Online Education

University students have experienced massive disruption in the wake of COVID-19 in the form of online education. Online education has required students to be more self-regulated, and the present research is interested in determining how this self-regulated education system impacts students and whether they are able to meet their needs of experienced competence, autonomy, and relatedness? What resources aid them in getting these things? The paper begins with an exploration of Self-Determination Theory and Resilience. Resilience has long been considered a part of basic psychological need satisfaction. Self Determination Theory says that experienced competence, autonomy, and relatedness are core pieces for personal growth, social development, psychological wellbeing. Need satisfaction can help create better coping habits in times of stress. SDT has been promoted in the classroom for the last few years because of this.

One Recommender Fits All? An Exploration of User Satisfaction With Text-Based News Recommender Systems

Journalistic media increasingly address changing user behaviour online by implementing algorithmic recommendations on their pages. While social media extensively rely on user data for personalized recommendations, journalistic media may choose to aim to improve the user experience based on textual features such as thematic similarity. From a societal viewpoint, these recommendations should be as diverse as possible. Users, however, tend to prefer recommendations that enable “serendipity”—the perception of an item as a welcome surprise that strikes just the right balance between more similarly useful but still novel content. By conducting a representative online survey with n = 588 respondents, we investigate how users evaluate algorithmic news recommendations (recommendation satisfaction, as well as perceived novelty and unexpectedness) based on different similarity settings and how individual dispositions (news interest, civic information norm, need for cognitive closure, etc.) may affect these evaluations. The core piece of our survey is a self-programmed recommendation system that accesses a database of vectorized news articles. Respondents search for a personally relevant keyword and select a suitable article, after which another article is recommended automatically, at random, using one of three similarity settings. Our findings show that users prefer recommendations of the most similar articles, which are at the same time perceived as novel, but not necessarily unexpected. However, user evaluations will differ depending on personal characteristics such as formal education, the civic information norm, and the need for cognitive closure.

Impact of a Punching Process on the SyRM Iron Loss: SPICE Model as an Effective Tool for Iron Loss Modeling

Many technologies for cutting the magnetic laminations, from which electric motors cores are built, change material properties, among which are magnetizability and iron loss, thus affecting the motor parameters such as motor efficiency. This problem is particularly important for low-power motors, in which the dimensions of the magnetic circuit elements are relatively small. The correct estimation of the motor efficiency is important as early as at its design stage. This is possible when the correct material characteristics are used. This knowledge and analytical model enabling fast estimation of material properties (depending on the actual size) are necessary for engineers, who design electrical motors by analyzing many solution variants in a short time. The author proposes an analytical model of changing material properties, implemented in SPICE software. Its effectiveness was compared with measurement results while being a competitive solution in relation to other analytical models. The proposed SPICE model allowed evaluating material properties for lamination of any width. In the end, the knowledge concerning the material properties was used to calculate the iron loss in the stator of the SyRM motor, showing the need to use the material characteristics calculated for the specified width of the core piece.

Design Flexibility of a Modular Low-Loss High-Frequency Inductor Structure

Miniaturization and efficiency of power electronics are limited by magnetic components, which are difficult to scale to small size and high frequency (HF). Inductor structures using field shaping, quasi-distributed gaps, and modular construction can achieve low loss at HF (3-30 MHz) without litz wire. For widespread adoption though, these structures must be shown to remain effective across a wide design range and be economical to manufacture. This article investigates the design flexibility of one such previously proposed inductor structure with a modified pot core and demonstrates that this structure can provide excellent performance for a wide range of inductance and power handling requirements using only a few sets of manufactured core pieces. The core pieces used in the modified pot core structure can be scaled by 4× in volume, compared to roughly 2× for conventional core families, and still achieve high performance over a wide design space. Moreover, this approach can achieve about half the loss of conventional designs at HF and, unlike conventional core sets, can provide a range of low-loss form factors with a single family of components. The proposed inductor structure and design approaches, thus, offer new opportunities in the practical production of low-loss HF inductors.

Alternative Facts in Musicology and Vechnaya Pamyat' in Shostakovich's Symphony No. 5

The assertions, refutations, and counter-refutations concerning two core pieces of Richard Taruskin’s studies on Russian music—Tchaikovsky’s Symphony No. 6 and Shostakovich’s Symphony No. 5—provide a starting point for discussion about the possibilities, limits, and obligations of musicological interpretation. Moreover, an important aspect of the discussion is the phenomenon of “alternative facts,” both in publication and in pedagogy, and possibly in music itself.
 Taruskin argues against the logical fallacies of overly specific or overly simplistic interpretations, but hesitates to fully interpret certain music himself, thereby participating in the web of alternative facts. Taruskin refutes popular myths about biographical meanings in Tchaikovsky’s symphony, but in so doing, also seems to reject a tragic reading of any kind. He explains away various musical structures and extroversive references, but fails to explore why those elements are in fact present.
 As for Shostakovich’s symphony, Taruskin notes its saturation with musical topics, but ignores their allusive specificity, downplaying their significance altogether for what he calls their transferability. Yet Taruskin himself identifies an allusion to a specific Orthodox hymn, and therefrom draws specific conclusions. His evidence for calling the passage a “literal imitation” is actually flawed, but a truly literal quotation of this very hymn may be present throughout the entire symphony, and may act as a sort of species of alternative fact itself. In any case, something that specific, and its placement in the symphonic structure, deserve notice and demand specificity of interpretation.

Erkenntnisse aus den „Tunnel Seismic While Drilling” Messungen während des Vortriebs am Koralmtunnel Baulos KAT2

AbstractThe 32.9 km long Koralm tunnel (Austria) is the core piece of the Koralm railway and will be one of the longest railway tunnels worldwide after completion. At the longest construction section ”KAT2“ two approx. 17 km long parallel single‐track tunnels were driven by two double‐shield tunnel boring machines with a diameter of about 10 m. Accompanying the tunnelling of the two tubes, the continuous Tunnel Seismic While Drilling (TSWD) method was used shortly after the start of mechanical excavation in January 2013 until the final position was reached in February 2018. The aim was to consistently explore the rock mass up to 100 m in front of the tunnel face to detect faults and water‐bearing zones which were relevant for tunnel construction. Another purpose of the measurements was to reduce the number of exploration drillings ahead of the tunnel face. After an initial test phase of about 5000 m, where exploration drillings were continuously carried out parallel with TSWD, an advanced and optimized exploration concept was evaluated and performed for permanent operation. This paper summarizes the findings gained from the TSWD measurements at this tunnel site.

On prediction, refutation, and explanatory reach: A consideration of the Interpersonal Theory of Suicidal Behavior

Theory proposition, empirical evaluation, and resulting support or refutation are core pieces of the scientific process. These steps of theory-testing, however, can be complicated by relative rigidity and dogmatism, in combination with the logistical challenges inherent in conducting comprehensive, real-world tests of theories explicating complex scientific phenomena, especially rare ones. It may be argued that suicide is one such phenomenon, and one for which the field of psychology has struggled to develop satisfactory understanding. One leading theory of suicide, the Interpersonal Theory of Suicide, has garnered attention and, to a considerable degree, has weathered substantial scrutiny. Still, it is arguable that the theory has yet to be tested in full—that is, in accordance with all propositions originally put forth. In this effort, we sought to evaluate the current state of knowledge regarding the Interpersonal Theory of Suicide, as well as to suggest potential directions via which future work may proceed. We draw from the fields of philosophy, psychology, physics, and engineering in the hopes of engendering curiosity and critical thought about the assumptions researchers (ourselves included) bring to their work. We direct particular attention to the role of refutation in theory-testing; the supposed dichotomy of explanatory vs. algorithmic approaches; and the categorization of research programs as progressive vs. degenerative. In doing so, we hope not only to promote these ideas in the study of suicidal behavior but also to empiricists of all creeds and foci. We also include implications for suicide prevention efforts.

Evaluation of the Diametrical Core Deformation and Discing Analyses for In-Situ Stress Estimation and Application to the 4.9\xa0km Deep Rock Core from the Basel Geothermal Borehole, Switzerland

The in situ state of rock mass stresses is a key design parameter, e.g., for deep engineered geothermal systems. However, knowledge of the stress state at great depths is sparse mostly because of the lack of possible in situ tests in deep boreholes. Among different options, core-based in situ stress estimation may provide valuable stress information though core-based techniques have not yet become a standard. In this study we focus on the Diametrical Core Deformation Analysis (DCDA) technique using monzogranitic to monzonitic rock drill cores from 4.9 km depth of the Basel-1 borehole in Switzerland. With DCDA the maximum and minimum horizontal stress (SHmax and Shmin) directions, and the horizontal differential stress magnitudes (∆S) can be estimated from rock cores extracted from vertical boreholes. Our study has three goals: first, to assess photogrammetric core scanning to conduct DCDA; second, to compare DCDA results with borehole breakout and stress-induced core discing fracture (CDF) data sets; and third, to investigate the impact of rock elastic anisotropy on ∆S. Our study reveals that photogrammetric scanning can be used to extract reliable core diametrical data and CDF traces. Locally aligned core pieces showed similar SHmax orientations, conform to borehole breakout results. However, the variability of core diametrical differences was large for the Basel-1 core pieces, which leads to a large spread of ∆S. Finally, we demonstrate that core elastic anisotropy must be considered, requiring robust estimates of rock elastic moduli, to receive valuable stress information from DCDA analyses.

Performance Improvement of Spoke-shaped Interior Permanent Magnet Magnetic Gear

Magnetic gears have several advantages such as having low acoustic noise and being maintenance-free because there is no mechanical contact. Among these gears, the flux-modulated type has a higher torque density and efficiency than the other types. Therefore, it is expected to be put into practical use. In previous papers, a spoke-shaped interior permanent magnet (IPM) rotor structure was proposed in order to reduce the eddy current loss in magnets. This paper presents three methods for improving the performance of the spoke-shaped IPM magnetic gear. First, the position of the magnetic bridges is changed from the air gap side to the back yoke side to increase the effective magnetic flux. Second, amorphous alloy is used for the rotor core and pole pieces in order to reduce iron loss. Third, bonded Nd-Fe-B magnets for canceling the leakage flux are arranged to sandwich the inner rotor from both sides. As a result of prototype tests, the measured maximum torque of the proposed spoke-shaped IPM magnetic gear was 44% higher than that of the conventional one. In addition, the measured maximum efficiency reached 99.85% at 100 rpm.

ADMISSIBILITY DIAGNOSTICS OF USING A FOERSTER PROBE AS PART OF A MAGNETOMETER

We have discussed a diagnostics method to assess the admissibility of using a Foerster probe as part of a magnetometer. The diagnostics is based on the compatibility analysis of the magnetic field (MF) induction (B) conversion by a Foerster probe with the parameters of a specific series of Foerster probe output signal converters (OSC). As a reference source of MF, we have used the Earth’s MF. The analysis uses a Foerster probe magnetometer designed according to the MF compensation method in the Foerster probe core piece. The subject of our analysis is the value of the OSC output signal under normal climatic conditions (NCCs), when the Foerster probe is exposed to extreme temperatures. Following the diagnostics, we have made a YES/NO decision on the admissibility of using a Foerster probe with OSCs of this series. As OSC parameters, that limit the use of a Foerster probe, we have adopted the values of the minimum and maximum codes of a digital-to-analog OSC converter, as allowed by relevant documents. The first two diagnostics stages are carried out with inductions of ±Bcon under NCCs, taking into account the Foerster probe zero offset. In this case, Bcon ˂ Вmax, where Вmax is the Foerster probe’s working range. Two subsequent diagnostics stages are carried out using the calculated and experimental characteristics, taking into account the Foerster probe zero offset under effect of extreme temperatures of different signs. We have demonstrated the temperature error specifics and presented the diagnostics algorithm.

Topology and start-up strategy for DC–DC transformers based on voltage balancing unit

As a core piece of equipment in DC distribution networks, DC solid-state transformers (DCSSTs) are attracting more and more attention in academia and industry. Due to the limitations in terms of the electrical stress of the switches, the input series output parallel (ISOP) structure is adopted in DCSSTs. This paper proposed an improved DCSST topology based on a voltage balancing unit (VBU). This topology has the advantages of higher power density, reduced weight, and cascaded number without compromising efficiency, cost, or reliability. The working modes, mathematical models, and control strategy are analyzed. In addition, a start-up strategy and a parameter design method are proposed in this paper. Simulation and experimental results verify the correctness and effectiveness of the proposed solution. The proposed DCSST is a practical scheme for the application of DC distribution networks.

RETRACTED: On the direction of talent training of design education from the perspective of the characteristics of design disciplines

This paper will analyze by analogy, the internal relationship between different design majors is clarified on the basis of discussing the characteristics of design disciplines, and then the talent cultivation direction of design education is discussed. From the point of view of the characteristics of design as a subject, the discipline of design is comprehensive and application-oriented. It is comprehensive as it involves different types of disciplines such as technical skills, abstract concepts and theoretical knowledge, and different types of knowledge such as knowledge about practical skills, human thinking and information, as well as different types of capabilities such as professional skills, creative thinking, knowledge acquisition and application. The knowledge structure of the design subject consists of three dimensions, the thinking level, knowledge level and technical level. The inherent connections of the different branches of the design discipline are as follows: they are interconnected on the thinking level, related on the knowledge level and different on the skill level. The knowledge and abilities on these three dimensions compose the design skills designers should acquire, among which the thinking level serves as the foundational and core piece. Therefore, the design education reform should focus on cultivating students’ abilities, especially students’ thinking skills. Then, it can be concluded that design education should not emphasize the difference of design direction, but should pay attention to the training of students' design ability instead of the training of students' skills, especially the training of students' thinking ability.