bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simultaneous imaging of widely differing particle concentrations in MPI: problem statement and algorithmic proposal for improvement
Authors: Boberg Marija , Gdaniec Nadine , Szwargulski Patryk , Werner Franziska , Möddel Martin , Knopp Tobias 
Published: March 2021

Abstract
Magnetic particle imaging (MPI) is a tomographic imaging technique for determining the spatial distribution of superparamagnetic nanoparticles. Current MPI systems are capable of imaging iron masses over a wide dynamic range of more than four orders of magnitude. In theory, this range could be further increased using adaptive amplifiers, which prevent signal clipping. While this applies to a single sample, the dynamic range is severely limited if several samples with different concentrations or strongly inhomogeneous particle distributions are considered. One scenario that occurs quite frequently in pre-clinical applications is that a highly concentrated tracer bolus in the vascular system ‘shadows’ nearby organs with lower effective tracer concentrations. The root cause of the problem is the ill-posedness of the MPI imaging operator, which requires regularization for stable reconstruction. In this work, we introduce a simple two-step algorithm that increases the dynamic range by a factor of four. Furthermore, the algorithm enables spatially adaptive regularization, i.e. highly concentrated signals can be reconstructed with maximum spatial resolution, while low concentrated signals are strongly regularized to prevent noise amplification.
Three-dimensional visualization and improved quantification with super-resolution ultrasound imaging - validation framework for analysis of microvascular morphology using a chicken embryo model
Authors: Özdemir İpek , Johnson Kenneth , Mohr-Allen Shelby , Peak Kara E , Varner Victor , Hoyt Kenneth 
Published: March 2021

Abstract
The purpose of this study was to improve the morphological analysis of microvascular networks depicted in three-dimensional (3D) super-resolution ultrasound (SR-US) images. This was supported by qualitative and quantitative validation by comparison to matched brightfield microscopy and traditional B-mode ultrasound (US) images. Contrast-enhanced US (CEUS) images were collected using a preclinical US scanner (Vevo 3100, FUJIFILM VisualSonics Inc.) equipped with an MX250 linear array transducer. CEUS imaging was performed after administration of a microbubble (MB) contrast agent into the vitelline network of a developing chicken embryo. Volume data was collected by mechanically scanning the US transducer throughout a tissue volume-of-interest in 90 μm step increments. CEUS images were collected at each increment and stored as in-phase/quadrature data (2000 frames at 152 frames per sec). SR-US images were created for each cross-sectional plane using established data processing methods. All SR-US images were then used to reconstruct a final 3D volume for vessel diameter (VD) quantification and for surface rendering. VD quantification from the 3D SR-US data exhibited an average error of 6.1% ± 6.0% when compared with matched brightfield microscopy images, whereas measurements from B-mode US images had an average error of 77.1% ± 68.9%. Volume and surface renderings in 3D space enabled qualitative validation and improved visualization of small vessels below the axial resolution of the US system. Overall, 3D SR-US image reconstructions depicted the microvascular network of the developing chicken embryos. Improved visualization of isolated vessels and quantification of microvascular morphology from SR-US images achieved a considerably greater accuracy compared to B-mode US measurements.
Spherical plasma focus operated with nitrogen and neon gases for soft x-rays (bremsstrahlung radiation, line radiation, and radiative recombination)
Authors: Ay Yasar 
Published: March 2021

Abstract
X-ray emissions (bremsstrahlung radiation, line radiation, and radiative recombination) from spherical plasma focus (SPF) device are investigated with the developed spherical MHD model for nitrogen (N) and neon (Ne) gases with respect to gas pressure, which is varied from 0.1 Torr to 7 Torr. Ion density, plasma velocity, pinch temperature, and peak current are also calculated for N and Ne gases. The total capacitance, external inductance, charging voltage, and stored energy as the operational conditions of the SPF device in this study are 432 µF, 36 nH, 25 kV, and 135 kJ. The maximum current is achieved at 7 Torr for both N (1561 kA) and Ne (1525 kA). It is found that there is an optimum pressure point for both x-rays (bremsstrahlung radiation, line radiation, and radiative recombination) and the used gases (N and Ne), separately. While the optimum pressure of bremsstrahlung radiation for N and Ne gases are 0.9 Torr and 1 Torr, respectively, these optimum pressures of radiative recombination and line radiation are 1 Torr for N gas and 1.1 Torr for Ne gas, respectively. It is also found that line radiation constitutes the big portion of the soft x-ray (SXR) emissions from SPF device. Line radiations of N at 1 Torr and Ne at 1.1 Torr are 911 J (91% of total N SXRs) and 3036.5 J (93.1% of total Ne SXRs), respectively, which shows that SPF device can be considered as a good SXR source. Ion densities and peak currents at 7 Torr are calculated as 21.88 × 1023 m−3 with 1561 kA peak current for N gas and 15.98 × 1023 m−3 with 1525 kA peak current for Ne gas.
2D Particle-in-cell simulations of charged particle dynamics in geometrically asymmetric low pressure capacitive RF plasmas
Authors: Wang Li , Hartmann Peter , Donkó Zoltán , Song Yuan-Hong , Schulze Julian 
Published: March 2021

Abstract
Understanding the spatio-temporal dynamics of charged particles in low pressure radio frequency capacitively coupled plasmas (CCP) is the basis for knowledge based process development in these plasma sources. Due to the importance of kinetic non-local effects the particle in cell/Monte Carlo collision (PIC/MCC) simulation became the primary modeling approach. However, due to computational limitations most previous PIC/MCC simulations were restricted to spatial resolution in one dimension. Additionally, most previous studies were based on oversimplified treatments of plasma-surface interactions. Overcoming these problems could clearly lead to a more realistic description of the physics of these plasma sources. In this work, the effects of the reactor geometry in combination with realistic heavy particle and electron induced secondary electron emission coefficients (SEEC) on the charged particle dynamics are revealed by GPU based 2D3V PIC/MCC simulations of argon discharges operated at 0.5 Pa and at a high voltage amplitude of 1000 V. The geometrical reactor asymmetry as well as the SEECs are found to affect the power absorption dynamics and distribution functions of electrons and ions strongly by determining the sheath voltages and widths adjacent to powered and grounded surface elements as well as via the self-excitation of the plasma series resonance. It is noticed that secondary electrons play important roles even at low pressures. Electron induced secondary electrons (δ-electrons) are found to cause up to half of the total ionization, while heavy particle induced secondary electrons (γ-electrons) do not cause much ionization directly, but induce most of the δ-electron emission from boundary surfaces. The fundamental insights obtained into the 2D-space resolved charged particle dynamics are used to understand the formation of energy distribution functions of electrons and ions for different reactor geometries and surface conditions.
Resistive transition of hydrogen-rich superconductors
Authors: Talantsev Evgeny F , Stolze Karoline 
Published: March 2021

Abstract
Critical temperature, T
c, and transition width, ΔT
c, are two primary parameters of the superconducting transition. The latter parameter reflects the superconducting state disturbance originating from the thermodynamic fluctuations, atomic disorder, applied magnetic field, the presence of secondary crystalline phases, applied pressure, etc. Recently, Hirsch and Marsiglio (2021 Phys. Rev. B
103 134505, doi: 10.1103/PhysRevB.103.134505) performed an analysis of the transition width in several near-room-temperature superconductors and reported that the reduced transition width, ΔT
c/T
c, in these materials does not follow the conventional trend of transition width broadening in applied magnetic field observed in low- and high-T
c superconductors. Here, we present a thorough mathematical analysis of the magnetoresistive data, R(T, B), for the high-entropy alloy (ScZrNb)0.65[RhPd]0.35 and hydrogen-rich superconductors of Im-3m-H3S, C2/m-LaH10 and P63
/mmc-CeH9. We found that the reduced transition width, ΔT
c/T
c, in these materials follows a conventional broadening trend in applied magnetic field.
Grain boundary diffusion in bilayered Ag/Cu thin film under diffusion-induced and intrinsic stresses
Authors: Lian Songyou , Xu Congkang , Wang Jiangyong , Swart Hendrik C , Terblans Jacobus J 
Published: March 2021

Abstract
The influences of the diffusion-induced stress due to the difference in the radii of elements in an alloy and the intrinsic stress originating mainly from the surface or other kind of external stress, on the grain boundary diffusion are evaluated. A model for the grain boundary (GB) diffusion under stress is developed. The stress distributions are obtained for the cases that the free surface acts as a diffusion barrier or has a rapid surface diffusion. The average concentration depth profiles are simulated upon the change of the diffusion-induced stress, the intrinsic stress, the ratio of the volume diffusion coefficient to the grain boundary diffusion coefficient, and the diffusion time. The simulation results reveal that the tensile/compressive intrinsic stress hinder/enhance the grain boundary diffusion process. The developed model for the GB diffusion under stress is applied to the bilayered Ag/Cu film deposited on an inert substrate.
Unsupervised outlier detection in heavy-ion collisions
Authors: Thaprasop P , Zhou K , Steinheimer J , Herold C 
Published: March 2021

Abstract
We present different methods of unsupervised learning which can be used for outlier detection in high energy nuclear collisions. This method is of particular interest for heavy ion collisions where a direct comparison of experimental data to model simulations is often ambiguous and it is not easy to determine whether an observation is due to new physics, an incomplete understanding of the known physics or an experimental artefact. The UrQMD model is used to generate the bulk background of events as well as different variants of outlier events which may result from misidentified centrality or detector malfunctions. The methods presented here can be generalized to different and novel physics effects. To detect the outliers, dimensional reduction algorithms are implemented, speciftically the Principle Component Analysis (PCA) and Autoencoders (AEN). We find that mainly the reconstruction error is a good measure to distinguish outliers from background. The performance of the algorithms is compared using a ROC curve. It is shown that the number of reduced (encoded) dimensions to describe a single event contributes significantly to the performance of the outlier detection task. We find that the model which is best suited to separate outlier events requires a good performance in reconstructing events and at the same time a small number of parameters.
Finding proper time intervals for dynamic network extraction
Authors: Orman Günce Keziban , Türe Nadir , Balcisoy Selim , Boz Hasan Alp 
Published: March 2021

Abstract
Extracting a proper dynamic network for modeling a time-dependent complex system is an important issue. Building a correct model is related to finding out critical time points where a system exhibits considerable change. In this work, we propose to measure network similarity to detect proper time intervals. We develop three similarity metrics, node, link, and neighborhood similarities, for any consecutive snapshots of a dynamic network. Rather than a label or a user-defined threshold, we use statistically expected values of proposed similarities under a null-model to state whether the system changes critically. We experimented on two different data sets with different temporal dynamics: the Wi-Fi access points logs of a university campus and Enron emails. Results show that, first, proposed similarities reflect similar signal trends with network topological properties with less noisy signals, and their scores are scale invariant. Second, proposed similarities generate better signals than adjacency correlation with optimal noise and diversity. Third, using statistically expected values allows us to find different time intervals for a system, leading to the extraction of non-redundant snapshots for dynamic network modeling.
Developing a physics textbook based on the local wisdom of Hulu Sungai Selatan regency to train rakat mufakat characters
Authors: Fitriah L , Ma’rifah E , Misbah M 
Published: March 2021

Abstract
This research was conducted due to the unavailability of textbook in Basic Physics 1 course especially in heat and temperature topic containing the South Kalimantan local wisdom so that students did not understand their culture well. Furthermore, students’ learning outcome were still not good. Therefore, this study aimed at producing physics textbook that contained heat and temperature topic based on the local wisdom of Hulu Sungai Selatan (HSS) Regency in South Borneo Province which was feasible based on the validity, the effectiveness, and the achievement of rakat mufakat characters. This study was a research and development using the ADDIE model. The instruments used were validation sheet, questionnaire, and achievement test. The results showed that the validity of the textbook was in highly valid category, the effectiveness was in medium category, and the attainment of rakat mufakat character was in very good category. Therefore, it could be concluded based on this research that the physics textbook based on local wisdom of HSS Regency is feasible to use in Basic Physics 1 course to train rakat mufakat characters.
Students’ Mathematical Communication Ability in Solving Trigonometric Problems
Authors: Utami L F , Pramudya I , Slamet I 
Published: March 2021

Abstract
Mathematical communication ability is a person’s ability to convey mathematical ideas orally or in writing which are presented in the form of graphs, tables, diagrams, symbols, or mathematical models. The purpose of this study is to determine and describe the level of mathematical communication ability of students. This type of research is a qualitative descriptive study. The sampling technique was using a purposive sampling technique. The results showed that the percentage of students’ mathematical communication ability in the text writing indicator, 38% of students were in the poor category, 50% of students were in the moderate category, 11% of students were in a good category, and 4% of students were in the very good category. On the drawing indicator, 7% of students were in the poor category, 57% of students were in a low category, and 36% of students were in the moderate category. 14% of students were in the poor category, 50% of students were in a low category, 18% of students were in the moderate category, 11% of students were in a good category, and 7% of students were in the very good category.
Analysis of mathematical critical thinking skills: The impact of RMS (reading, mind mapping, and sharing) learning model assisted by PPW (props, powerpoint, and worksheet)
Authors: Mutiara Panca Ayu , Achmad Fafiru , Alief Maulana , Lindasari Lisa Mei , Supriadi Nanang , Putra Fredi Ganda , Kusuma Arie Purwa , Rahmawati Nurina Kurniasari 
Published: March 2021

AbstractMathematical critical thinking skills arerequired to improve the understanding of mathematics. The purpose of this research was to determine the influence of the RMS learning model (reading, mind mapping, and sharing) assisted by PPW (Props, PowerPoints, and Worksheets) toward students’ thinking skills. This research is experimental research with a quasi-experimental design. The cluster random sampling technique was used to determine the sample. The data collection techniques used were tests. Before the tests were administered, they were tested using the realistic test, validity test, difficulty test, and discrimination index test. The data analysis technique used in this research wasthe one-way ANAVA with unequal cells. The results of the analysis showed that: Fobserved= 3.101296 <Fcritical= 4.076109 which indicated that H0was rejected. This indicated that there was an influence of the RMS learning model assisted by PPW on the students’ thinking skills. Furthermore, concerning the hypothesis testing and data analysis, the result was that the RMS learning model assisted by PPW could significantly affect students’ mathematical critical thinking skills.
Analysis of mathematical creative thinking level based on logical mathematical intelligence
Authors: Prastika V Y A , Riyadi  , Siswanto  
Published: March 2021

Abstract
Creativity is an ability that must be developed from an early age. The ability to think creatively is also one of the higher-order thinking skills needed in the 21st century. This study aimed to analyze the level of mathematical creative thinking skills of students’ mathematical logical intelligence. Indicators on the ability to think creatively include fluency, flexibility, and novelty. The method used in this research was descriptive qualitative. Data filling methods were tests, interviews, and documentation. The results of this study revealed the profile of students’ level of mathematical critical thinking and logical mathematical intelligence, and showed that students who have high mathematical logical intelligence are at level 3 creative thinking (creative). Students who have mathematical moderate logical intelligence are at level 2 creative thinking (creative enough) and students who have low mathematical logical intelligence are at creative thinking level 0 (not creative). Therefore, based on the results of this study, we know that students who have high, medium, and low mathematical logical intelligence can solve math problems based on their creative thinking abilities.
Analysis of critical thinking in junior high school students through science learning in Indonesia: A systematic review
Authors: Billah Arif , Masykuri Mohammad , Sarwanto  , Sajidan  
Published: March 2021

Abstract
The purpose of this study was to see the results of the research analysis regarding the critical thinking of junior high school students through science lessons in Indonesia. This research was a systematic review of studies through the Scopus database. Search was done through nine stages with criteria at each predetermined stage, i.e.: stage I, initial search with the keywords “critical thinking” with the category “article title”; stage II, type of access “open access”; stage III, published in “2010 – 2018”; stage IV, “English” language; stage V, the type of source “journals and proceedings”; stage VI, keywords “critical thinking”; stage VII, “Indonesia” research location; stage VIII, field of study “Science”; and stage IX, “Junior High School” education level. Searching through these nine stages results in 13 articles. The focus of this study was to analyze critical thinking skills and the indicators used in these studies. Most studies reported that increasing the critical thinking skills of Junior High School students in Indonesia were still at a “moderate” level. This study recommends to do further research on experimentation-based learning with an environmental approach to enhance critical thinking skills.
Blended learning model: The effect on physics problem-solving skills viewed from self-efficacy
Authors: Susanti Agus , Diani Rahma , Satiarti Rina Budi , Munawaroh Rohimatun , Fujiani Dwi 
Published: March 2021

Abstract
This study aimed to determine the effect of the blended learning model on the problem-solving skills of students with high and low self-efficacy as well as their interactions. The research method used was a quasi-experimental research with nonequivalent control group design. The population of this study was all tenth-grade science students of SMA Al-Azhar 3 Bandar Lampung. The sampling technique used was random. The instruments employed in this study were a test in the form of essay questions to measure students’ problem-solving skills, a questionnaire to measure self-efficacy, and observation sheets. The hypothesis had been tested using 2 way ANOVA. The results of the hypothesis testing are as follows: 1) there was an effect of using the blended learning model on problem-solving skills in terms of self-efficacy, 2) there was an effect of self-efficacy on problem-solving abilities, and 3) there was no interaction between the blended learning model and self-efficacy.
The validity and practicality of the student worksheet using STEM-based multiple representations in physics learning
Authors: Anggraeni A A , Distrik I W , Rosidin U 
Published: March 2021

Abstract
The objective of this research was to produce a valid and practical student worksheet using Science Technology Engineering and Mathematics (STEM)-based multiple representations and integrated with twenty first century learning in vibration and wave topic. This research used Research and Development (R & D) method by following 4-D model steps. 15 sample students of grade XI were taken with random sampling. Research instruments were validation sheets, student worksheet implementation observation sheets, and questionnaires. Data were analyzed descriptively and qualitatively. The result showed that the student worksheet by using STEM approach based on integrated multiple representations and integrated with twenty first century learning was: 1) valid by content with average score of 85.41 and valid by construct with average score of 83.88; 2) practical to use in vibrations and waves learning materials and it was shown by average student worksheet implementation by above 80% and 86.66% positive students’ responses to the student worksheet.
The Development of 3D Flipbook E-Learning Module of English Mathematics Profession
Authors: Evenddy S S , Hamer W , Pujiastuti H , Haryadi R 
Published: March 2021

AbstractThis development research aimed to design a 3D Flipbook e-learning module and determine students’ perceptions of the developed 3D Flipbook e-learning module. The research method used was development research with the ADDIE development model which consisted of Analyse, Design, Develop, Implement, and Evaluate stages. The instruments used in this study were validation sheets of material experts and media experts, pre-test and post-test quizzes, and questionnaire sheets. This feasibility of the developed 3D Flipbook e-learning module was verified by the content experts, media experts, and trials to the preservice teacher at Sultan Ageng Tirtayasa University. The validation by material experts obtained a percentage of 86.97%, the validation by media experts obtained a percentage of 89.65%, and trials to students obtained a percentage of 78.7%. Overall, it can be concluded that this teaching material is good and appropriate to be used to facilitate students in learning English in the mathematics profession. For data processing using normalized gain techniques, the results were obtained in the medium category 0.3 ≤ g <0.7 equal to 0.669048. It can be concluded that the 3D Flipbook e-learning module is quite effective and suitable to be used in classroom learning.