bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-length scale hierarchical architecture overcoming pressure sensing range-speed tradeoff for skin electronics
Authors: Tian Qiong , Yan Wenrong , Chen Tianding , Ho Derek
Published: November 2021

Ultra-sensitive pressure sensing is provided hierarchically, on the nanoscale by contact between silver nanoflakes and LIG nanosheets, and on the microscale by contact between AgMFs and LIG.
A high refractive index resist for UV-nanoimprint soft lithography based on titanium-containing elemental polymer oligomers
Authors: Qiu Junlun , Hu Getian , Wang Yuqiao , Wang Yurui , Luo Ming , Hu Xin
Published: November 2021

A UV-curable high refractive index resist (nD = 1.7063) for UV-nanoimprint lithography is synthesized and the refractive index can be further improved to 1.7327 after baking. 50 nm resolution patterns are faithfully imprinted into the resist film.
The impact of fluorine atoms on a triphenylamine-based dopant-free hole-selective layer for perovskite solar cells
Authors: Ghaderian Abolfazl , Pegu Meenakshi , Hemasiri Naveen Harindu , Huang Peng , Ahmad Shahzada , Kazim Samrana
Published: November 2021

A cost-effective, dopant-free, hydrophobic fluorinated triphenylamine-based hole transporting material is developed to improve the performance and long-term stability of perovskite solar cells.
Bioinformatics analysis of tumor-educated platelet microRNAs in patients with hepatocellular carcinoma
Authors: Zhu Beibei , Gu Shanshan , Wu Xiaoting , He Wenyong , Zhou Hongke
Published: November 2021

Background: Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies that seriously threaten global health. The primary reason for its grim prognosis is the lack of sensitive tools for early diagnosis. The purpose of the present study was to apply bioinformatics analysis to explore tumor-educated platelet (TEP) microRNA (miRNA) expression and its potential diagnostic utility in HCC.

Methods: Twenty-five HCC patients and 25 healthy controls were included. RNA sequencing was utilized to screen miRNA alterations in platelets derived from HCC patients (n=5) and controls (n=5). Gene set enrichment analysis was performed to analyze the targeted mRNAs of differentially expressed miRNAs by using the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, aiming at main functions and pathways, respectively. We then verified the selected platelet miRNAs in another cohort by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) amplification.

Results: A total of 250 differentially expressed miRNAs were identified, among which 111 were down-regulated and 139 were up-regulated. The functional enrichment analysis of differentially expressed miRNAs suggested that their target genes were involved primarily in pathways related to HCC. Expression levels of miR-495-3p and miR-1293 were further validated by qRT-PCR, which yielded results consistent with the sequencing analysis. The area under the receiver operating characteristic (ROC) curve of miR-495-3p and miR-1293 as diagnostic tests for HCC were 0.76 and 0.78, respectively.

Conclusion: TEP miRNAs such as miR-495-3p and miR-1293 were differentially expressed in HCC patients, and may be involved in the pathophysiology of HCC.
OGLE-2019-BLG-0468Lb,c: Two microlensing giant planets around a G-type star
Authors: Han Cheongho , Udalski Andrzej , Lee Chung-Uk , Kim Doeon , Zhu Wei , Albrow Michael D. , Chung Sun-Ju , Gould Andrew , Hwang Kyu-Ha , Jung Youn Kil , Kim Hyoun-Woo , Ryu Yoon-Hyun , Shin In-Gu , Shvartzvald Yossi , Yee Jennifer C. , Zang Weicheng , Cha Sang-Mok , Kim Dong-Jin , Kim Seung-Lee , Lee Dong-Joo , Lee Yongseok , Park Byeong-Gon , Pogge Richard W. , Kim Chun-Hwey , Kim Woong-Tae , Mróz Przemek , Szymański Michał K. , Skowron Jan , Poleski Radosław , Soszyński Igor , Pietrukowicz Paweł , Kozłowski Szymon , Rybicki Krzysztof A. , Iwanek Patryk , Ulaczyk Krzysztof , Wrona Marcin , Gromadzki Mariusz , Buckley David , Dong Subo , Luo Ali
Published: November 2021

Aims. With the aim of interpreting anomalous lensing events with no suggested models, we conducted a project of reinvestigating microlensing data collected in and before the 2019 season. In this work, we report a multi-planet system, OGLE-2019-BLG-0468L, that was found as a result of this project.

Methods. The light curve of the lensing event OGLE-2019-BLG-0468, which consists of three distinctive anomaly features, could not be explained by the usual binary-lens or binary-source interpretations. We find a solution that explains all anomaly features with a triple-lens interpretation, in which the lens is composed of two planets and their host, making the lens the fourth multi-planet system securely found by microlensing.

Results. The two planets have masses of ~3.4 MJ and ~10.2 MJ, and they are orbiting around a G-type star with a mass of ~0.9 M⊙ and a distance of ~4.4 kpc. The host of the planets is most likely responsible for the light of the baseline object, although the possibility of the host being a companion to the baseline object cannot be ruled out.
Investigating the kinetics at low temperature heat pump drying and conventional drying of osmotic dehydrated blueberries
Authors: Hristo Hristov , Svetoslav Aleksandrov , Todorka Petrova , Milena Ruskova , Velitchka Gotcheva , Penov Nikolay
Published: November 2021

The possibilities for low-temperature heat pump and conventional drying of blueberries during preliminary osmotic dehydration was studied. A full factor experiment of type 22+3 was performed. The kinetics of the process during variation of the main mode parameters: inlet temperature and thickness of the drying layer (load on the scaffolding) was studied. The curves of the drying process U = f (τ) and the curves of the drying speed dU / dτ = f (U) were constructed. The influence of the regime parameters on the drying time was established. Regression models of the drying coefficient during the second period of drying were presented.
Simulation Investigation of the Wind Load of Photovoltaic Panels
Authors: Stoyanov Ivaylo , Iliev Teodor , Mihaylov Grigor
Published: November 2021

In this article, a simulation and evaluation of the mechanical stress exerted by the wind on photovoltaic panels is performed. The stresses of the solar cells in a PV module are calculated using the finite element method, taking into account the wind pressure and the allowable mechanical stresses, according to the regulatory requirements. Seven different operating positions of the photovoltaic panel during its rotation from 0° to 90° are considered. In each of these positions, a distributed load for computer simulations is 1 kN/m2. It is clear from them that for all operating positions of the panel, the maximum stresses are obtained in its frame. These stresses in different cases vary around the value of 50 MPa and are not dangerous for the structure.
Electronic measuring system design for photovoltaic panels analysis
Authors: Yordanov Krastin , Hadzhidimov Iliya , Zlateva Penka
Published: November 2021

The article presents the design and manufacture of an electronic measuring system based on an ESP32 microcontroller equipped with LORA E32 wireless data transceivers, a SD card for data recording and a computer with application for photovoltaic panels testing. Under environmental conditions the system has been experimentally tested to determine the efficiency of photovoltaic panels, which depends primarily on solar radiation and ambient parameters. In addition, the current, voltage and surface temperatures on the back side of the panels have been measured. The measuring sensors are selected in order to achieve the goal set, as well the durability of the system. The rising of the surface temperature of the photovoltaic panels have a significant effect on module’s efficiency, increasing the risk of losing energy production. In the experimental study, temperature, solar radiation, current and voltage have been measured to refine the effect on a monocrystalline and polycrystalline structure of photovoltaic panel. The test has been performed on the experimental field of the Technical University of Varna, Bulgaria. Also, the ambient meteorological parameters during the experiment are reported by a weather station mounted on the experimental field, which transmits data online in the global meteorological database Wunderground with name IVARNA50.
On the Development of a Real Time Water Monitoring System
Authors: Zaharia Sandel , Iana Gabriel , Monea Cristian , Sandu Mihnea
Published: November 2021

The goal of the paper starts from the need for real-time monitoring of both running water and its affluents and urban sewerage systems with a role in discharging wastewater. The idea is to assess water quality and to determine the sources of pollutants resulting from human activity. The data quality will be obtained by purchasing them with a high resolution, both spatial and temporal, using multi-parametric sensors on a hardware platform of its own multisensory acquisition. The acquired data is stored in CLOUD or local server for storage, analysis and interpretation. There will be a software application based on artificial intelligence technologies that serves to identify and classify different polluted areas, locate pollution sources, predict their extinction, degree of pollution and help make decisions based on real-time detection. A web application will provide all the data collected in the field and it can be accessed on a common online platform. This allows researchers or employees of relevant agencies as well as city sewer system operators to validate the quality of data purchased from sensors and end users to be sure of their correctness.
Design and constructive – technological development for children’s art clothing
Authors: Atanasova Radka , Pavlova Magdalena , Merkova Monika
Published: November 2021

The present study directs research and creative activity towards the realization of a design and constructive-technological concept for children's art clothing. The collection consists of clothes that are inspired by the children's imaginary world - fairy tale characters, animals, fruits. The educational function of the clothing is sought. The choice of models is subject to comfort and freedom of movement. The artistic design of the products in the collection is realized with the help of software for creating and processing images. The process of construction and modelling is algorithmized and performed automatically using a specialized CAD clothing system. The technological and operational maps are algorithmized and developed on CorelDraw. The designed constructions can be used for modelling a wide range of clothing for children.
Experimental study of the accuracy of measuring of a central water meter
Authors: Bekriev Ognyan , Stanilov Aleksandar
Published: November 2021

The paper presents the results of a study of the error of a central water meter at different modes of water consumption. A stand has been designed for the purpose of the study and tests of the error of the water meter have been performed, in compliance with the requirements of Measuring Instruments (MID) Directive (2014/32/EU). The errors of the water meter have been determined in the area close to its start mode, which is not included in the area of inspection. The measuring errors have been also determined in specific operation modes with frequent starts and stops, associated with the flow of smaller water quantities. The study contains an analysis of the obtained differences in the accuracy of measurement during metrological verification of the water meter and reading on a real site. A quantitative estimate of the established losses in water metering is given.
A new climatological electron density model for supporting space weather services
Authors: Hoque Mohammed Mainul , Jakowski Norbert , Prol Fabricio S.
Published: November 2021

The ionosphere is the ionized part of the Earth’s atmosphere, ranging from about 60 km up to several Earth radii, whereas the upper part above about 1000 km height up to the plasmapause is usually called the plasmasphere. We present a new three-dimensional electron density model to support space weather services and mitigate propagation errors for trans-ionospheric signals. The model is developed by superposing the Neustrelitz Plasmasphere Model (NPSM) to an ionosphere model composed of separate F and E-layer distributions. It uses the Neustrelitz TEC model (NTCM), Neustrelitz Peak Density Model (NPDM), and the Neustrelitz Peak Height Model (NPHM) for the total electron content (TEC), peak ionization, and peak height information. These models describe the spatial and temporal variability of the key parameters as a function of local time, geographic/geomagnetic location, solar irradiation, and activity. The model is developed to calculate the electron concentration at any given location and time in the ionosphere for trans-ionospheric applications and named the Neustrelitz Electron Density Model (NEDM2020). A comprehensive validation study is conducted against electron density in-situ data from DMSP and Swarm, Van Allen Probes and ICON missions, and topside TEC data from COSMIC/FORMOSAT-3 mission, bottom side TEC data from TOPEX/Poseidon mission, and ground-based TEC data from International GNSS Service (IGS) covering both high and low solar activity conditions. Additionally, the model performance is compared with the 3D electron density model NeQuick2. Our investigation shows that the NEDM2020 performs better than the NeQuick2 compared with the in-situ data from Van Allen Probes and ICON satellites and TEC data from COSMIC and TOPEX/Poseidon missions. When compared with DMSP and IGS TEC data, both NEDM2020 and NeQuick2 perform very similarly.
Neurally Adjusted Ventilatory Assist in Very Prematurely Born Infants with Evolving/Established Bronchopulmonary Dysplasia
Authors: Shetty Sandeep , Evans Katie , Cornuaud Peter , Kulkarni Anay , Duffy Donovan , Greenough Anne
Published: November 2021

Background During neurally adjusted ventilatory assist (NAVA)/noninvasive (NIV) NAVA, a modified nasogastric feeding tube with electrodes monitors the electrical activity of the diaphragm (Edi). The Edi waveform determines the delivered pressure from the ventilator.

Objective Our objective was to determine whether NAVA/NIV-NAVA has advantages in infants with evolving/established bronchopulmonary dysplasia (BPD).

Methods Each infant who received NAVA/NIV-NAVA and conventional invasive and NIV was matched with two historical controls. Eighteen NAVA/NIV-NAVA infants’ median gestational age, 25.3 (23.6–28.1) weeks, was compared with 36 historical controls’ median gestational age 25.2 (23.1–29.1) weeks.

Results Infants on NAVA/NIV-NAVA had lower extubation failure rates (median: 0 [0–2] vs. 1 [0–6] p = 0.002), shorter durations of invasive ventilation (median: 30.5, [1–90] vs. 40.5 [11–199] days, p = 0.046), and total duration of invasive and NIV to the point of discharge to the local hospital (median: 80 [57–140] vs. 103.5 [60–246] days, p = 0.026). The overall length of stay (LOS) was lower in NAVA/NIVNAVA group (111.5 [78–183] vs. 140 [82–266] days, p = 0.019). There were no significant differences in BPD (17/18 [94%] vs. 32/36 [89%] p = 0.511) or home oxygen rates (14/18 [78%] vs. 23/36 [64%] p = 0.305).

Conclusion The combination of NAVA/NIV-NAVA compared with conventional invasive and NIV modes may be advantageous for preterm infants with evolving/established BPD.
Smart Hospital Logistics: Digitale Transformation der Prozessnetzwerke im Krankenhaus
Authors: Brandl Paul , Kriegel Johannes
Published: November 2021

Aktuell weisen Krankenhäuser bezüglich ihrer realen und digitalen Aktivitäten und Prozesse eine ausgeprägte Komplexität und Intransparenz auf, die einen suboptimalen Ressourceneinsatz begünstigen. Basis für eine zukünftige Weiterentwicklung der hybriden Leistungserstellung und einer verbesserten Ressourceneffizienz ist eine digitale Transformation der Prozessnetzwerke im Krankenhaus.
More than sample providers: how genetic researchers in Pakistan mobilized a prenatal diagnostic service for thalassemia
Authors: Sheikh Zainab Afshan , Wahlberg Ayo
Published: November 2021

While unequally resourced partners from the so-called global South are often considered ‘mere sample providers’ in larger international genomics collaborations, in this paper, we show how they strategically work to mobilize their role in a global system of tissue exchange to deliver services for local communities. We unpack how a prenatal diagnostic service for thalassemia in Pakistan emerged out of the maneuvering efforts of internationally connected Pakistani researchers. By tracing the distributed capacities that emerged and circulated as they set about improving medical genetics in Pakistan, we outline some key conditions that led to the establishment of the service: first, the scale of unmet needs that geneticists faced when collecting data as part of their research that made medical genomics a relevant field; secondly, joint efforts between researchers and physicians that were engaged with the challenge of decreasing disease prevalence through diagnostics and abortion; and finally, the ways in which international research collaborations helped generate resources to improve medical genetics in Pakistan. To understand how genetic research and medicine is currently being developed in Pakistan, we need to ethnographically re-center our analyses in ways that allow us to identify the resourceful ways in which researchers maneuvre to secure locally relevant outcomes.
An improved measurement scheme of the large-caliber steady-state magnetic-field testing system for ITER
Authors: Huang Ya , Jiang Li , Lei Hong , Gao Ge , Deng Xi , Wu Peng , Zhang Jie
Published: November 2021

The large-caliber steady-state magnetic-field testing system is an important device for the International Thermonuclear Experimental Reactor, which is mainly used for electromagnetic compatibility tests in a strong magnetic field environment. The uniform magnetic field area needs to be measured to ensure the correctness of the design after the completion of the platform. This paper mainly analyzes the relationship between the magnetic field probe and error, studies the detection effect of different arrangement methods of magnetic field probe points, and obtains a more accurate probe arrangement method through comparative analysis. Then, the principle and structure of the acquisition and detection system are studied, and the multipoint synchronous Hall array magnetic field detection system of the magnetic field is built by using the Hall probe to realize the omnidirectional measurement of the magnetic field. Finally, the Hall probe is calibrated and tested by experiments, and a test platform is built to test the magnetic field. The results verify the correctness of the analysis.
A car-based portable atom gravimeter and its application in field gravity survey
Authors: Zhang Jiong-Yang , Xu Wen-Jie , Sun Shi-Da , Shu Yu-Biao , Luo Qin , Cheng Yuan , Hu Zhong-Kun , Zhou Min-Kang
Published: November 2021

As a novel instrument for measuring absolute gravity, the atom gravimeter has shown high sensitivity and stability in the past three decades. In this work, we report a car-based portable atom gravimeter whose sensitivity is at the level of 1.9mGal/Hz (1 Gal = 0.01 m/s2) both for lab and outdoor measurements. Its resolution can reach 30 μGal within an integration time of 10 000 s when located in a quiet place. During four months of gravity observation, there is no drift for the measurement result, showing that this car-based gravimeter has a competitive advantage at long term stability. By using this car-based atom gravimeter in the open air, the field gravity measurements with sub-mGal performance have been demonstrated in the mountain gravity survey. According to the gravity measurement results from our car-based atom gravimeter, the density distribution of this mountain is inverted, which is consistent with the result from the geological exploration.
Resilience of the pastoral component of Moroccan small ruminant systems in mountain areas
Authors: El Aayadi Soufiane , Araba Abdelilah , Jouven Magali
Published: November 2021

Small ruminant farming is the main rural occupation in mountain areas of Morocco. This activity is subject to numerous pressures, including repeated climatic hazards that modify pastoral resource availability and trigger changes in production systems. This study aimed to identify and analyse changes in availability and utilisation of pastoral resources acknowledged by farmers over the past 40 years for the small ruminant farming systems of the Central High Atlas region of Morocco. We hypothesised, on the basis of previous research, that resilience of the pastoral component of such systems increases with elevation. We interviewed 50 farmers in three municipalities of Azilal province, at moderate (800–1400 m), medium (1400–1800 m) and high (1800–3000 m) elevations. In the 1970–1980s, pastoral resources were abundant and mobile flocks grazed collective rangelands. Subsequently, repeated droughts and the increased stock numbers promoted by agricultural policies led to the deterioration of resource abundance and quality, especially palatable plants. At moderate elevations, wooded areas and phytomass declined; erosion occurred at high elevations. Traditional systems diversified by including agricultural activities. At moderate elevations, livestock farming intensified, with the adoption of a productive breed, concentrate distribution and the grazing of fallow land. Currently, flock mobility is limited and rangelands provide less than 60% of sheep requirements. At high elevations, the pastoral component persisted at the cost of a diversification of pastoral areas and greater flock mobility. Rangelands are still collectively managed and provide almost 90% of sheep requirements. Since rangelands remain a major feed source, changes in pastoral resources can be considered as a major driver of change in livestock systems. The sustainability of small ruminant farming systems at these elevations thus depends on the conservation of rangeland.
The active grandparent hypothesis: Physical activity and the evolution of extended human healthspans and lifespans
Authors: Lieberman Daniel E. , Kistner Timothy M. , Richard Daniel , Lee I-Min , Baggish Aaron L.
Published: November 2021

The proximate mechanisms by which physical activity (PA) slows senescence and decreases morbidity and mortality have been extensively documented. However, we lack an ultimate, evolutionary explanation for why lifelong PA, particularly during middle and older age, promotes health. As the growing worldwide epidemic of physical inactivity accelerates the prevalence of noncommunicable diseases among aging populations, integrating evolutionary and biomedical perspectives can foster new insights into how and why lifelong PA helps preserve health and extend lifespans. Building on previous life-history research, we assess the evidence that humans were selected not just to live several decades after they cease reproducing but also to be moderately physically active during those postreproductive years. We next review the longstanding hypothesis that PA promotes health by allocating energy away from potentially harmful overinvestments in fat storage and reproductive tissues and propose the novel hypothesis that PA also stimulates energy allocation toward repair and maintenance processes. We hypothesize that selection in humans for lifelong PA, including during postreproductive years to provision offspring, promoted selection for both energy allocation pathways which synergistically slow senescence and reduce vulnerability to many forms of chronic diseases. As a result, extended human healthspans and lifespans are both a cause and an effect of habitual PA, helping explain why lack of lifelong PA in humans can increase disease risk and reduce longevity.
Rational regulation of water-seeking effort in rodents
Authors: Reinagel Pamela
Published: November 2021

Significance

We confirm that rats can act as rational economic agents, making choices about how much work to do to obtain a reward in a way that optimally trades off the value of the reward against the cost of the effort. Contrary to the notion that bigger rewards are more motivating, rats worked harder in economies where rewards were small, ensuring a sufficient minimum income of water. But they chose to earn and consume more water per day when water was “cheap” (available for little work). We present a mathematical model explaining why rats work when they do (surprisingly, not just when they are thirsty) and suggesting where in the brain animals might compute the current value of working for water.
Literalization in the self-revision process of novice and experienced biomedical translators
Authors: Valdez Susana
Published: November 2021

This paper explores decision-making in translation focusing on the self-revision process of novice and experienced
translators of biomedical content in the English to European Portuguese language pair. Adopting process- and product-oriented
methods, an experiment was designed to study thirty translations of a 244-word instructional text about a medical device intended
for health professionals. The data elicited from fifteen novice translators and fifteen experienced translators included
keylogging and screen-recording data. These data were triangulated and analyzed to describe the translation solutions in the
interim and final versions in response to problematic translation units and to test if, during the self-revision process, novice
and experienced translators tend to proceed from more literal versions to less literal ones, or vice versa, in biomedical
translation. Contrary to expectations, the analysis points towards a literalization phenomenon in the translators’ processes. The
data also indicates that the tendency to proceed from less literal versions to more literal ones is more pronounced in novice
translators than in experienced translators. The findings reported here shed new light on the self-revision processes of novice
and experienced translators and their relationship with prevailing translation norms, and enable us to better understand the
practices in place in professional biomedical translation.
Rethinking the ‘patron–client’ politics of oil block allocation, development and remittances in Nigeria
Authors: Iwuoha Victor Chidubem
Published: November 2021

This research adopts qualitative method and patron–client analysis to underscore the political economy of oil block allocation, development and receipts/remittances in Nigeria. It contests Wilson’s (1961) and Scott’s (1972) claims on the superiority of the patron over clients, and argues that ‘clients’ in Nigeria (indigenous oil block awardees) maintain some degree of control over the patron (ruling elite), enjoy more economic returns/oil rents, and possess some leverage over the patrons’ decision-making power. The ruling elite’s personalisation of oil block allocation/rents results in poor development of the upstream oil sector by ‘clients’, defaults in oil remittances and a consistent decline in oil production. The author recommends that the bidding process for oil block allocation be carried out in a more transparent and competitive manner.
Dirac procedure and the Hamiltonian formalism for cosmological perturbations in a Bianchi I universe
Authors: Boldrin Alice , Małkiewicz Przemysław
Published: November 2021

We apply the Dirac procedure for constrained systems to the Arnowitt–Deser–Misner formalism linearized around the Bianchi I universe. We discuss and employ basic concepts such as Dirac observables, Dirac brackets, gauge-fixing conditions, reduced phase space, physical Hamiltonian, canonical isomorphism between different gauge-fixing surfaces and spacetime reconstruction. We relate this approach to the gauge-fixing procedure for non-perturbative canonical relativity. We discuss the issue of propagating a basis for the scalar-vector-tensor decomposition as, in an anisotropic universe, the wavefronts of plane waves undergo a nontrivial evolution. We show that the definition of a gravitational wave as a traceless-transverse mode of the metric perturbation needs to be revised. Moreover there exist coordinate systems in which a polarization mode of the gravitational wave is given entirely in terms of a scalar metric perturbation. We first develop the formalism for the universe with a single minimally coupled scalar field and then extend it to the multi-field case. The obtained fully canonical formalism will serve as a starting point for a complete quantization of the cosmological perturbations and the cosmological background.
Why do we choose the fastest point as a reference to measure the simple pendulum period by a stopwatch?
Authors: Kim Soyeon , Lee Soyeon , Moon Su Jin , Kim Kyuhwan , Kim Jung Bog
Published: November 2021

Since the vibration of a single pendulum is very periodic, measuring its period is a very interesting topic. When students are asked to measure the period of a single vibration, they start and stop the stopwatch when the pendulum reaches the top point as a reference point. In this paper, we try to show that the error can be reduced more by using the equilibrium point, that is, the bottom position as the reference rather than the top position. We think it would be beneficial for students to measure the period in both cases, compare the errors, and think about the reasons for error differences. Students believe that the moment the pendulum moved slowly and nearly stopped at the top was more likely to measure the time to be more accurate. The reason for this is that they think the pendulum will move so fast when it passes the bottom point that they will not be able to start or stop the stopwatch accurately at the instant passing the lowest point. We are also able to obtain the error of the position measurement by using the recorded video of a simple pendulum.
Simple device for spectroscopy laboratory exercises
Authors: Bušovský Damián , Křížová Michaela , Kříž Jan , Loskot Jan , Studnička Filip , Šlégrová Leontýna , Šlégr Jan
Published: November 2021

Undergraduate physics laboratory exercises are very important in shaping students’ attitude to science, especially for future teachers. Recently, it is necessary to look for ways to easily create large quantities of experimental sets, not only for institutional use, but also for sets that can be produced in large quantities and distributed for use in distance learning. In this paper, we briefly describe the various ways to support the teaching of wave optics, and then describe one of the possible methods for performing undergraduate spectroscopic measurements using a 3D printed spectroscope and light source.
Normal light dispersion in laboratory experiments
Authors: Mayer V V , Varaksina E I
Published: November 2021

We propose a laboratory experiment on the quantitative study of the normal dispersion of light. A triangular isosceles prism made of flint glass TF3 is used as the object of study, and we describe a simple and affordable device for observing and photographing the dispersion spectrum on a smartphone. A possibility of the quantitative investigation of light dispersion is provided by using a modern miniature mercury lamp emitting a line spectrum of mercury vapour against the background of a solid spectrum of white light. The method of processing experimental results is stated.
Transient buildup and dissipation of a compressed plasma shockwave in arc-discharge plasma beams
Authors: Zhang Zhe , Fu Yifeng , Zhang Zun , Lin Xin , Qi Jiayun , Ling William Yeong Liang , Tang Haibin , Herdrich Georg
Published: November 2021

Electric propulsion offers the advantage of a high specific impulse through a large exhaust velocity and has seen significant progress in space flight applications. Recently, we observed a transient plasma shockwave during pulsed plasma thruster operation when the plasma beam impacted a probe surface. However, details regarding the plasma shockwave formation are still unknown. This work is an experimental investigation of the compression-induced plasma shockwave in the presence of a planar obstruction. To study the complete shockwave buildup and dissipation process, an ultra-high-speed imaging system was set up to visualize the time-resolved shockwave morphology at a sub-microsecond level. In addition, the local magnetic field and plasma density were measured using 2D magnetic coils and a triple Langmuir probe, respectively. The successive images of the shockwave give us a comprehensive understanding of the shockwave buildup process. During the 12 μs operational period of the thruster, two shockwaves were formed during the first cycle of the discharge. It is also interesting to note that there is a 1 μs dissipation period between the two shockwaves with the same cloud of plasma compressing against the probe surface. A shockwave model is also developed to predict the appearance of the two shockwaves. The implication is that the local magnetic field strength can be a key indicator for the plasma shockwave buildup and dissipation process.
CMB anisotropies and linear matter power spectrum in models with non-thermal neutrinos and primordial magnetic fields
Authors: Kunze Kerstin E.
Published: November 2021

Angular power spectra of temperature anisotropies and
polarization of the cosmic microwave background (CMB) as well as the
linear matter power spectra are calculated for models with three
light neutrinos with non-thermal phase-space distributions in the
presence of a primordial stochastic magnetic field. The non-thermal
phase-space distribution function is assumed to be the sum of a
Fermi-Dirac and a gaussian distribution. It is found that the known
effective description of the non-thermal model in terms of a twin
thermal model with extra relativistic degrees of freedom can also be
extended to models including a stochastic magnetic field. Numerical
solutions are obtained for a range of magnetic field parameters.
η mesons in hot magnetized nuclear matter
Authors: Kumar Rajesh , Kumar Arvind
Published: November 2021

interactions are investigated in hot magnetized asymmetric nuclear matter using the chiral SU(3) model and chiral perturbation theory (ChPT). In the chiral model, the in-medium properties of η-mesons are calculated using medium modified scalar densities under the influence of an external magnetic field. Further, in a combined chiral model and ChPT approach, off-shell contributions of the

interactions are evaluated from the ChPT effective

Lagrangian, and the in-medium effect of scalar densities are incorporated from the chiral SU(3) model. We find that the magnetic field has a significant effect on the in-medium mass and optical potential of η mesons, and we observe a deeper mass-shift in the combined chiral model and ChPT approach than in the solo chiral SU(3) model. In both approaches, no additional mass-shift is observed due to the uncharged nature of η mesons in the presence of a magnetic field.
System scan of the multiplicity correlation between forward and backward rapidities in relativistic heavy-ion collisions using a multi-phase transport model *
Authors: Li Yi-An , Wang Dong-Fang , Zhang Song , Ma Yu-Gang
Published: November 2021

A systematic study on forward–backward (FB) multiplicity correlations from large systems to small ones through a multi-phase transport model (AMPT) has been performed and the phenomenon that correlation strength increases with centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian distributions. It is also found that correlations in the

plane can imply the shape of the event. Furthermore, long-range correlations originate from the fluctuations associated with the source information. FB correlations allow us to decouple long-range correlations from short-range correlations, and may provide a chance to investigate the α-clustering structure in initial colliding light nuclei as well. It seems the tetrahedron 16O + 16O collision gives a more uniform and symmetrical fireball, that emits the final particles more isotropically or independently in the longitudinal direction, indicating that the forward–backward multiplicity correlation could be used to identify the pattern of α-clustered 16O in future experiments.
Optimization and fast prototyping of polymer parts exposed to cyclic loading
Authors: Marek V
Published: November 2021

Many mechatronic systems operate with parts made of polymers. This cost-effective solution is also easy to design. Manufacturing is trivial for producers who produce millions of parts. The solution is more complicated when the fatigue and loading is a significant factor. The paper describes the development of polymer parts that are loaded by cyclic operation. The number of cycles in a specific application can be around 1 million. The specific case also deals with a corrosion environment around these components. Gasses in the environment cause degradation of material and failure of parts made of specific polymers. This interaction limits the choice of suitable materials. The mechanism operates in two directions which define the opening of a valve and free turn. Two variants of elastic valves were analysed. Loading states were simulated by final element methods. Internal stresses and contact stresses were analysed. Results were compared with long-term test results. The material creep and other material properties define the function of elastic parts after thousands of cycles. The technology of mould fabrication was analysed considering simplification and general effectivity of production. Prototype valves were printed by FDM 3D printer and tested. Prototype moulds were printed by SLA 3D printer, which produces high-temperature stable polymer. This procedure shows cost-effective prototype development and test procedures.
Improving measuring line parameters of the UIC test bench
Authors: Pribilinec F , Čajkovič L
Published: November 2021

This article deals with the description of the management of variable braking force at the request of multi-level braking on certification test bench UIC. The device is used to analyze the frictional properties of rolling stock brake accessory components. The introduction of the article describes and approaches the function of the measurement and control process. Based on the UIC standard, the requirement for variable braking force for multi-level braking is described. The conclusion of the article is devoted to evaluating the accuracy of measured data and analyzing undesirable phenomena.
Longitudinal critically refracted (LCR) ultrasonic wave for residual stress measurement
Authors: Geľatko M , Hatala M , Vandžura R , Botko F
Published: November 2021

The article deals with the state-of-the-art in the field of Longitudinal critically refracted (LCR) ultrasonic wave, for non-destructive material evaluation. It checks its capability for residual stress identification, and reviews positives and negatives related to its use. Obtained information within the article, are used for the understanding of essence of method and for the evaluation of its use in the engineering practice. The article can be the source of information about the LCRwave measurement technology, which is the part of the complex ultrasonic testing method. For the frequency of using this technology for surface residual stress measurement, it is appropriate to have this information in one whole, which are gathered of the outputs of researches by various authors. The paper is divided in few sections and sub-sections. In the first section, information about LCRwave technique and factors correlated with this method, are provided. The next section writes about residual stresses and the importance of their identification. Next, the principal of residual stresses measurement and basic structure of measurement device, is described. A significant part of study, describes the state so far of theoretical and practical researches within the use of this method, in the technological practice of residual stress identification in surface layers of engineering components. In the conclusion, obtained knowledges are summarised and evaluated. Related positive and negative aspects are included, with a verifying the need of future researches.
Selection of parameters during shredding of corn stalks as an additive to the polymer
Authors: Macko M , Łączny D , Lewandowski J
Published: November 2021

This paper presents the results of research on the process of grinding dried corn stalks to use them as polylactide filler. Shredding was carried out on a laboratory shredder with the use of a design variant based on discs with cylindrical holes. By selecting the design variant, the appropriate grinding speed and the material pressure on the shredder discs, the most favourable parameters in terms of the quality of the shredded product and low energy consumption were selected. The research was conducted to reduce the energy demand during the shredding process and to obtain the shredded material suitable for further processing steps.
The influence of suspension nonlinearities on fatigue assessment of vehicle structure
Authors: Klockiewicz Zbyszko , Spadło Mikołaj , Ślaski Grzegorz
Published: November 2021

Load spectrums for the fatigue analysis were created using suspension responses generated in a simulation of vehicle and suspension vertical dynamics nonlinear model for different conditions of vehicle use. The next stage presented was the use of finite element method and analysis of obtained stresses with its transformation to a set of cycles that are used in the determination of fatigue characteristics. The qualitative and quantitative analysis of the stresses field in the vehicle structure and suspension elements was done and later the influence of suspension responses on the fatigue assessment for most loaded parts of suspension and vehicle structure. Lastly conclusions were drawn from the results describing qualitative and quantitative influence of different road class and load conditions on fatigue assessment of vehicle structure and suspension components. Conclusion on the proposed and used methodology also was drawn.
Computational Simulation of the Shear Test of a Multi-layered Long-Fibre Composite with a Polymer Matrix
Authors: Krmela J , Krmelová V , Artyukhov A , Sadjiep S , Bakošová A
Published: November 2021

This paper deals with the creation of a computational model of a multi-layered composite made of long fibres embedded in a polymer matrix and its use to simulate the response of the composite to a shear test. The research involves the determination of material parameters of the matrix (elastomer, in the context of the current paper) as well as of fibres (textile-cords and steel-cords). Careful attention is given to the Mooney-Rivlin parameters obtained from the elastomers tensile test for these simulations since shear tests have not been performed. Then by getting advantage of APDL (Ansys Parametric Design Language) in ANSYS, the computational model was successfully created and lastly simulated. The outputs obtained from the computational modelling will greatly help later to refine the orthotropic parameters of the composite, needed in future works to build up and achieve computational simulations of tires.
Kinematic and dynamic analysis and distribution of stress for seven-item mechanism by means of the SolidWorks program
Authors: Vavro J , Vavro J , Marček L , Taraba M , Klimek L
Published: November 2021

This paper presents a kinematic and dynamic analysis and distribution of the stress for seven-item planar mechanism by means of the SolidWorks software. The authors of the introduced paper deal with the kinematic analysis of planar mechanisms as well as with the implementation of the vector method into the SolidWorks software program in order to determine the kinematic variables (quantities) of the individual bodies in the whole complex system. The dynamic analysis is performed on the basis of the kinematic analysis. Dynamic analysis allows us to design a system of bodies correctly and it is with the respect to the dynamic loading. For the interpretation of the introduced analysis, the seven-item planar mechanism was selected. Graphic dependence of kinematic and dynamic magnitudes of some points is given in dependence on the angle of rotation of the driving item and in dependence on time. In relation to the kinematic and dynamic analysis and subsequent simulation of the planar as well as spatial mechanisms, it is perfect solution to use SolidWorks software program. The considerable advantage of this mentioned program is based on its simplicity from the aspect of modeling and moreover, it is important to point out that utilisation of the mentioned program leads to results which are precise and accurate in the case of the numerical solution of the equations in the whole magnitude referring to motion of mechanism while the given results are obtained in the graphic form.
Loading of thin composite plate by low-speed impact
Authors: Rychlíková L , Novák P , Skočilas J , Žmindák M , Skočilasová B , Soukup J
Published: November 2021

The article summarizes the experimental results from the experiments of loading thin composite plates by low-speed impact. The plates are made on a 3D printer from the material onyx-glass fiber and onyx-carbon fiber. Another investigated material was a pre-impregnated (resin-kevlar) plate. The theory of the impact load of the plate and basic parameters of the tested plates are presented. The plates were repeatedly loaded with low-speed impact weights, the responses of the plate to the impact (wave propagation in the plate) were measured. The experiment is supplemented by a numerical analysis. Damage to the plates was evaluated by NTD methods.
The impact of stiffness increasing in construction of tire measuring device to measured results
Authors: Bartoš M , Bulej V , Gál T , Zajacko I , Wiecek D
Published: November 2021

The article analyzes the influence of the construction stiffness of the measuring device and its effort to the resulting measured results. The article deals with the possibility of increasing the accuracy of measurement and at the same time reducing the measurement deviation on the measuring device by increasing the rigidity of the structure of the device. In the introduction, the article describes the stiffness, errors and analyzes the possibilities of increasing the accuracy of measurement on the measuring device and examines the causes of measurement deviations. In the next part, the article offers the possibilities of increasing the rigidity and strength of the measuring device. In the practical part, the structural modification of the device increasing the overall rigidity and strength of the structure is presented. In the practical part we made a simulation of old device frame and modified frame. In the last part, the article compares the results of measurements before the structural modification and after the structural modification of the increase in stiffness.
Application of continuous carbon fiber reinforced composites in a modular system
Authors: Svetlík J , Hrivniak L , Šašala M , Stejskal T
Published: November 2021

The article deals with the development of the construction of a second generation robotic manipulator designed on a modular principle. The manipulator consists of 6 separate rotary modules interconnected by passive members of the structure. In previous generations of the module, the high weight of the overall assembly, which limited the movement properties, proved to be a problem. Modifications to the structure no longer allowed for further weight reduction. Therefore, a change was made to the materials used for the passive members of the structure. The aluminium alloy was replaced by a continuous carbon fiber reinforced composite produced by additive technology. Modelling and simulation in CAD software was used in the modification of passive members, which was necessary in order to be able to design and manufacture composite parts.