bluuebunny/crossref_metadata_2025 huggingface dataset:
UV response characteristics of mixed-phase MgZnO thin films with different structure distributions, high Iuv/Idark ratios, and fast speed MgZnO UV detectors with tunneling breakdown mechanisms
Authors: Han Shun , Xia H , Lu Y M , Liu W J , Xu W Y , Fang M , Cao P J , Zhu D L
Published: February 2021

High-performance ultraviolet (UV) detectors with both high responses and fast speeds are hard to make on homogeneous crystal semiconductor materials. Here, the UV response characteristics of mixed-phase MgZnO thin films with different internal structure distributions are studied. The mixed-phase MgZnO-based detector with the given crystal composition has a high response at both deep UV light (96 A W−1 at 240 nm) and near UV light (80 A W−1 at 335 nm). Meanwhile, because of the quasi-tunneling breakdown mechanism within the device, the high-response UV detector also shows a fast response speed (tr = 0.11 μs) and recovery speed (td1 = 26 μs) at deep UV light, which is much faster than both low-response mixed-phase MgZnO-based UV detectors with other structure constitutions and reported high-response UV devices on homogenous crystal materials. The Idark of the device is just 4.27 pA under a 5 V bias voltage, so the signal-to-noise ratio of the device reached 23852 at 5.5 uW cm−2 235 nm UV light. The new quasi-tunneling breakdown mechanism is observed in some mixed-phase MgZnO thin films that contain both c-MgZnO and h-MgZnO parts, which introduce a high response, signal-to-noise ratio, and fast speed into mixed-phase MgZnO-based UV detectors at weak deep UV light.
Stereolithography (SLA) 3D printing of carbon fiber-graphene oxide (CF-GO) reinforced polymer lattices
Authors: Xiao Ran , Ding Mingyang , Wang Yuejiao , Gao Libo , Fan Rong , Lu Yang
Published: February 2021

Insufficient mechanical properties of stereolithography (SLA)-printed architected polymer metamaterial limits its wide applications such as in the areas of biomedicine and aerospace. One effective solution is to reinforce the structures with micro- or nano- fibers/particles, but their interfaces are critical for the reinforcement. In this work, a carbon fiber-graphene oxide (CF-GO) polymer composite resin and a mild annealing postprocess have been rationally designed and applied into the manufacturing of oct-truss (OCT) lattices. In situ carbon fiber pulling-out experiment was conducted to exhibit the improve effect of GO on the crosslink of the CF and the polymer matrix interface. We found that the maximum reinforcement was realized when the CF-GO (CF: GO is about 3: 1) content is about 0.8 wt%, followed with annealing. Compared with pure polymer lattices, the compression strength of the CF-GO polymer OCT lattices has been significantly increased from ∼0.22 to ∼2.4 MPa, almost 10 times enhancement. Importantly, the compression strength of the CF-GO polymer OCT lattice (3.08 MPa) further increased by ∼30% after optimized annealing. This work suggests an efficient reinforce strategy for SLA-printed metamaterials, and thus can be valuable for advancing various practical applications of mechanical metamaterials.
Dynamic measurement of the elastic constant of an helicoidal spring by a smartphone
Authors: Agliolo Gallitto Aurelio , Battaglia Onofrio Rosario , Fazio Claudio
Published: February 2021

We describe an educational activity that can be done by using smartphones to collect data in physics experiments aimed to measure the oscillating period of a spring-mass system and the elastic constant of the helicoidal spring by the dynamic method. Results for the oscillating period and for the elastic constant of the spring agree very well with measurements obtained by different methods. We also discuss the error analysis that can be done in an introductory physics laboratory at undergraduate level.
Effects on skin dose from unwanted air gaps under bolus in an MR-guided linear accelerator (MR-linac) system
Authors: Huang Chen-Yu , Yang Bin , Lam Wai Wang , Tang Ka Keung , Li Ting Chuan , Law Wai Kong , Cheung Kin Yin , Yu Siu Ki
Published: February 2021

Bolus is commonly used in MV photon radiotherapy to increase superficial dose and improve dose uniformity for treating shallow lesions. However, irregular patient body contours can cause unwanted air gaps between a bolus and patient skin. The resulting dosimetric errors could be exacerbated in MR-Linac treatments, as secondary electrons generated by photons are affected by the magnetic field. This study aimed to quantify the dosimetric effect of unwanted gaps between bolus and skin surface in an MR-Linac. A parallel-plate ionization chamber and EBT3 films were utilized to evaluate the surface dose under bolus with various gantry angles, field sizes, and different air gaps. The results of surface dose measurements were then compared to Monaco 5.40 Treatment Planning System (TPS) calculations. The suitability of using a parallel-plate chamber in MR-Linac measurement was validated by benchmarking the percentage depth dose and output factors with the microDiamond detector and air-filled ionization chamber measurements in water. A non-symmetric response of the parallel-plate chamber to oblique beams in the magnetic field was characterized. Unwanted air gaps significantly reduced the skin dose. For a frontal beam, skin dose was halved when there was a 5 mm gap, a much larger difference than in a conventional linac. Skin dose manifested a non-symmetric pattern in terms of gantry angle and gap size. The TPS overestimated skin dose in general, but shared the same trend with measurement when there was no air gap, or the gap size was larger than 5 mm. However, the calculated and measured results had a large discrepancy when the bolus-skin gap was below 5 mm. When treating superficial lesions, unwanted air gaps under the bolus will compromise the dosimetric goals. Our results highlight the importance of avoiding air gaps between bolus and skin when treating superficial lesions using an MR-Linac system.
Large-scale screening to distinguish between COVID-19 and community-acquired pneumonia using infection size-aware classification
Authors: Shi Feng , Xia Liming , Shan Fei , Song Bin , Wu Dijia , Wei Ying , Yuan Huan , Jiang Huiting , He Yichu , Gao Yaozong , Sui He , Shen Dinggang
Published: February 2021

The worldwide spread of coronavirus disease (COVID-19) has become a threat to global public health. It is of great importance to rapidly and accurately screen and distinguish patients with COVID-19 from those with community-acquired pneumonia (CAP). In this study, a total of 1,658 patients with COVID-19 and 1,027 CAP patients underwent thin-section CT and were enrolled. All images were preprocessed to obtain the segmentations of infections and lung fields. A set of handcrafted location-specific features was proposed to best capture the COVID-19 distribution pattern, in comparison to the conventional CT severity score (CT-SS) and radiomics features. An infection size-aware random forest method (iSARF) was proposed for discriminating COVID-19 from CAP. Experimental results show that the proposed method yielded its best performance when using the handcrafted features, with a sensitivity of 90.7%, a specificity of 87.2%, and an accuracy of 89.4% over state-of-the-art classifiers. Additional tests on 734 subjects, with thick slice images, demonstrates great generalizability. It is anticipated that our proposed framework could assist clinical decision making.
Reversal of laser wake phase velocity generates high-power broadband Cherenkov signal
Authors: Kalmykov Serge , Elle Jennifer , Schmitt-Sody Andreas
Published: February 2021

As a femtosecond terawatt laser pulse propagates along a positive density gradient within a stratified plasma column, it drives a low-frequency electromagnetic wake wave, the period of electron fluid oscillations in the wake gradually shrinking. Phase velocity of the wake promptly exceeds the vacuum speed of light, setting in near-forward emission of terahertz Cherenkov radiation. As the wake accelerates further, the Cherenkov emission ray rotates by 180∘. Emission from a given plasma locality is sustained for a finite interval of time, in the middle of which the wake experiences a ‘reversal,’ its phase velocity becoming singular and changing sign (Zhang C J et al 2017 Phys. Rev. Lett. 119 064801) At this instant, the electromagnetic energy flows at 90∘, the emission power reaching its peak. After the reversal, the wake keeps radiating into the rear hemisphere until its phase velocity becomes subluminal. Experimentally capturing evolution of the Cherenkov signal may thus shed light onto the plasma wake dynamics. Far away from the plasma, the radiation fills an expanding, almost spherical shell, the shell thickness increasing with an increase in the observation angle. The length of the terahertz signal sampled in the wave zone thus ranges from zero (forward emission) to a few tens of picoseconds (backward emission). The signal is positively chirped, its frequency increasing from the Langmuir frequency at the foot of the column to the Langmuir frequency at the top. Theoretical estimates for the regimes involving 10 TW-class drive pulses promise a few-kW emission power; the energy conversion efficiency, from optical to terahertz, of order 10−7; and an MV m−1-scale electric field strength centimeters away from the plasma.
Development of high-efficiency capacitive discharge using magnetic resonance wireless power transfer systems
Authors: Kim Ju Ho , Chung Chin-Wook
Published: February 2021

We developed a high-efficiency source in a capacitively coupled plasma using magnetic resonance wireless power transfer (MRWPT) systems, which has the advantage that the matcher efficiency is very high at low gas pressures (2 mTorr to 20 mTorr) and high density plasmas (about 1 × 1010 cm−3 to 5 × 1010 cm−3). At the non-resonance conditions, most of the RF power is dissipated by the transmitter coil and the plasma is not discharged. However, at the resonance condition, the plasma is discharged as the current flowing through the transmitter coil rapidly decreases, and the matcher efficiency is higher than 90% in all experiments. For analysis, the transformer model with MRWPT systems is developed. The experimental result is consistent with the model, and the results are discussed with the relevant physical mechanisms.
GaN HEMT based biosensor for the detection of breast cancer marker (C-erbB2)
Authors: Chaturvedi Nidhi , Chowdhury Rajdeep , Mishra Shivanshu , Singh Kuldip , Chaturvedi Nitin , Chauhan Ashok , Pande Surojit , Sharma Niketa , Parjapat Priyavart , Sharma Ramakant , Kothari Prateek , K Singh Arvind
Published: February 2021

This work reports on the development of a compact GaN high-electron-mobility transistor (HEMT) based biosensor for an easy and early detection of breast cancer biomarker C-erbB2 in the human cell line. The early-stage detection process includes a reaction of antibody-antigen through the cell line culture of a patient. The developed sensing chip has a two-finger gate structure of 125 µm gate width, and a gate length of 5 µm. In order to functionalize the gold surface of the fabricated sensor, the sensor chip has been immersed into an optimized 1 M aqueous solution of thioglycolic acid at room temperature for 15 h. Various characterization methods such as I–V, EDS, and FTIR confirm the formation of the Au–S complex. The functionalized sensors have been incubated in phosphate buffer saline solution of 200 µg ml−1 C-erbB2 monoclonal antibody for 4 h. Thereafter, the C-erbB2 monoclonal antibody conjugated devices are incubated with human cancer cells positive for C-erbB2 on its cell surface. The biosensor shows a 31% change in drain current for an incubation period of 6 h. The high-resolution biosensing chip (in terms of high drain current levels of the order of mA) is unaffected by noise and eases the circuit for futuristic point of care diagnostics.
Study of an eccentric dielectric elastomer motor and its application for soft robots
Authors: Chen Bicheng , Wang Nianfeng , Chen Haozheng , Zhang Xianmin
Published: February 2021

Dielectric elastomer actuator (DEA) is an attractive electro-active actuator, which has great potential in soft robots. This paper investigates the deformation and application of an eccentric dielectric elastomer (DE) motor constructed by a typical circle DEA and a central block. The motion of DE motor is achieved collaboratively by several electrode segments patterned on the DE film. The deformation of the motor under voltage is deduced according to the balance state between external force and dielectric elastomer film, and a revised angle is taken concerning large deformation of DE motor. Numerical results are presented and the effects of design parameters, loads and voltages are discussed. Experiments are taken for verification and the results show a good agreement with numerical results. The eccentric DE motor is used to finish the prescribed tasks including tracking and crawling through controlling voltages of different electrode segments.
Experiments and modeling of variable camber guide vane embedded with shape memory alloy plate
Authors: Chen Tiegang , Jiang Jun , Zhang Qiang , Wang Hanlin , Zhang Xiaoyong
Published: February 2021

In this paper, a novel variable camber guide vane (VCGV) actuated with a shape memory alloy (SMA) plate is proposed to achieve active real-time control. An analytical model is proposed to describe the relationship of SMA plates with different thicknesses between the deflection angle and temperature. Then, a numerical model of the VCGV is established to design the shape of the VCGV. Moreover, experiments of this actuator and VCGV are conducted to explore the variation of deflection angles over time for the VCGV. Results show that the deflection angle of the VCGV can be actively controlled from 0° to 8.2°. This work is expected to widen the applications of SMAs in variable guide vanes.
Theory of BCS-like bogolon-mediated superconductivity in transition metal dichalcogenides
Authors: Sun Meng , Parafilo A V , Villegas K H A , Kovalev V M , Savenko I G
Published: February 2021

We report on a novel mechanism of BCS-like superconductivity, mediated by a pair of Bogoliubov quasiparticles (bogolons). It takes place in hybrid systems consisting of a two-dimensional electron gas in a transition metal dichalcogenide monolayer in the vicinity of a Bose–Einstein condensate. Taking a system of two-dimensional indirect excitons as a testing ground of Bose-Einstein condensate we show, that the bogolon-pair-mediated electron pairing mechanism is stronger than phonon-mediated and single bogolon-mediated ones. We develop a microscopic theory of bogolon-pair-mediated superconductivity, based on the Schrieffer–Wolff transformation and the Gor’kov’s equations, study the temperature dependence of the superconducting gap and estimate the critical temperature of superconducting transition for various electron concentrations in the electron gas and the condensate densities.
Giant synthetic gauge field for spinless microcavity polaritons in crossed electric and magnetic fields
Authors: Chestnov I Y , Arakelian S M , Kavokin A V
Published: February 2021

The artificial gauge field for electrically neutral exciton polaritons devoid from the polarization degree of freedom can be synthesized by means of applying crossed electric and magnetic fields. The appearance of the gauge potential can be ascribed to the motional (magneto-electric) Stark effect which is responsible for the presence of a linear-in-momentum contribution to the exciton kinetic energy. We study the interplay of this phenomenon with the competing effect which arises from the Rabi-splitting renormalization due the reduction of the electron–hole overlap for a moving exciton. Accounting for this mechanism is crucial in the structures with the high ratio of Rabi splitting and the exciton binding energy. Besides, we propose an approach which boosts the gauge field in the considered system. It takes advantage of the crossover from the hydrogen-like exciton to the strongly dipole-polarized exciton state at a specific choice of electric and magnetic fields. The strong sensitivity of the exciton energy to the momentum in this regime leads to the large values of the gauge field. We consider the specific example of a GaAs ring-shape polariton Berry phase interferometer and show that the flux of the effective magnetic field may approach the flux quantum value in the considered crossover regime.
Delay time and persistent oscillations for a shifted quantum shutter
Authors: Hernández-Maldonado Alberto , Villavicencio Jorge , Hernández-Aviña Andrea
Published: February 2021

We derive an exact analytical solution to the time-dependent Schrödinger equation based on a resonant state expansion, to explore the time-evolution of cutoff plane waves scattered by finite range potentials, within a shifted quantum shutter model. The latter allows to control both, the position of the shutter and an hypothetical detector, which are initially separated by a distance ΔX. The dynamical advance-time (negative delay-time), ΔT, is explored for the particular case of a delta potential well, by measuring the difference of the first maxima of the time-diffraction pattern of the probability density, corresponding to the free and delta potential cases. We show that in general, ΔT exhibits a monotonic behaviour as a function of ΔX, and derive a simple formula for the timescale by using the symmetry and rescaling properties of the dynamical solution. We demonstrate that below a critical value of the shutter-detector separation, ΔX

c
, the monotonic behaviour of ΔT is hindered due to an oscillatory phenomena of the probability density, known as persistent oscillations, that drastically distorts the maxima used in the measurement process. These persistent oscillations are periodic Rabi-type oscillations that arise from an interplay between the incidence energy of the initial quantum wave and the bound state of the system, and their frequency play an important role in the dynamics of the delay time.
The three-dimensional equilibrium with magnetic islands and MHD instabilities in the CFQS quasi-axisymmetric stellarator
Authors: Wang X.Q. , Xu Y. , Shimizu A. , Isobe M. , Okamura S. , Todo Y. , Wang H. , Liu H.F. , Huang J. , Zhang X. , Liu H. , Cheng J. , Tang C.J.
Published: February 2021

The equilibrium of the Chinese first quasi-axisymmetric stellarator (CFQS) has been investigated by the HINT code. It is found that the stochastization of magnetic field lines expands with the increase in the volume-averaged beta value 〈β〉 in the plasma boundary. In the high-β regime, the generation of large magnetic islands at rational surfaces not only leads to an effective shrinkage of the plasma confinement region but also increases the outward shift of the magnetic axis. With bootstrap current effects, the low-order islands spread over the whole plasma area, leading to a stochastization of magnetic field lines due to island chain overlapping. However, for a flat pressure profile, the magnetic islands are significantly suppressed so that the magnetic surfaces can be fairly maintained. Moreover, the magnetohydrodynamic (MHD) instabilities in the optimized CFQS configurations have been simulated by the MEGA code. The linear properties of unstable resistive MHD modes are studied. The results show that in the CFQS the main MHD behaviour is dominated by the resistive ballooning modes with strong mode coupling. The mode structure and resistivity scaling are consistent with related theories.
Determination of Stability constants Nickel binary and ternary complexes in aquesous DMSO by Pontentiometric method
Authors: Rajarajan G. , Dhineshkumar E. , Amala S. , Seenivasan M. , Paramasivan A.
Published: February 2021

The stability constants of some of the binary and ternary system involving Nickel(II) have been studied. Bis-(pyridyl) benzilidene acts as a primary ligand. Glycine, L-alanine, L-phenylalanine, L-leucine and L-valine were acts as a secondary ligand. The stability constants of complex are calculated by SCOGS computer program. The reported values are ± 0.02 log unit accuracy. The protonation constants values increase with an increasing percentage of dimethyl sulphoxide. Protanation constants values for the glycine, L-valine ternary complexes higher stability constants indicate that inductive effect is predominant than steric effect. Whereas L-Phenylalanine ternary system has high stability constants than other ternary complexes due to stacking interaction between phenyl ring of phenylalanine and phenyl ring of primary ligand. The order of stability constant of ternary systems is Ni(bpb)(phe)2 > Ni(bpb)(leu)2 > Ni(bpb)(val)2 > Ni(bpb)(gly)2.
Mediative Fuzzy Logic of Sugeno-Tsk Model For The Diagnosis of Diabetes
Authors: Sharma M. K. , Dhiman Nitesh , Narayan Mishra Vishnu
Published: February 2021

Fuzzy Logic (FL) is very beneficial in medical field. But due to the consideration of membership function only; it cannot give an appropriate result in prese nt era of contradiction. So, we need to consider favourable as well as unfavourable cases together as the Intuitionistic Fuzzy Logic (IFL) does. But what happens if we have imperfect information that cannot be dealt with the IFL. When there-exist a contradiction in the expert knowledge, then we have to propose a Mediative Fuzzy Logic (MFL) based Sugeno’s inference system for the diagnosis of diabetes. In the present research paper, we have proposed a new approach to the diagnosis of diabetes, we have collected certain information from Pima Indians Diabetes Database (PIDD) as input variables and we used MFL based inference system for the diagnosis of diabetes.
Characterizations of Mapping via Nnc Z-open Sets
Authors: Moogambigai N. , Vadivel A. , Tamilselvan S.
Published: February 2021

The aim of this paper we introduce NncZ-irresolute, NncZ-open, NncZ-closed, pre NncZ-open and pre NncZ-closed mappings and investigate properties and characterizations of these new types of mappings.
Vulnerability Parameters of Tensor Product of Cycles
Authors: Sheeba Agnes V.
Published: February 2021

In this paper, the vulnerability parameters, namely, connectivity, toughness, scattering number, integrity and tenacity of the graph Cr
× Cs
, where Cn
denote the cycle of length n(⩾ 3) is determined.
Science online learning during the covid-19 pandemic: difficulties and challenges
Authors: Wisanti  , Ambawati R , Putri EK , Rahayu DA , Khaleyla F
Published: February 2021

Students, parents, and teachers in Indonesia get the tremendous effects of the coronavirus (Covid-19 Pandemic) when schools are closed and the rules of Large-Scale Social Restrictions (LSSR) were set to overcome the global pandemic. While the government is doing its best to handle the outbreak of the epidemic, teachers respond and strive to provide qualified education for their students during these difficult times. Sciences should be learned through minds-on and hands-on, hence teachers must be able to create virtual classroom conditions that help students maintain learning momentum while they cannot interact each other physically. This study aimed to identify the difficulties experienced by science teachers during online learning and describe the efforts of science teachers to conduct online learning during the Covid-19 pandemic. The research data were obtained through a survey using a semi-structured online questionnaire. The respondents were 82 junior high school teachers and 104 biology high school teachers in Indonesia. Data analysis used a quantitative descriptive approach. The results showed that the majority of science teachers (77.5%) got difficulty in managing online learning. This difficulty was identified in three main factors namely technology, students, and teachers. Internet access was a technological factor that causes the greatest difficulty (42.4%) in online learning. Other difficulties came from the students by 21.5%, including low motivation, time management skills that were not optimal, and the lack of communication devices such as smartphones. The third factor, namely teachers, contributed 36.1% of difficulties, especially related to the explanation of concepts and the use of online learning applications. Based on these difficulties, 77.4% of teachers made an effort to carry out online learning optimally by presenting the material and providing slide presentation, discussion, as well as learning evaluation. A small percentage of teachers (22.6%) used online classes only for task assignments and learning evaluation. The efforts of science teachers to manage online learning have not optimized students’ varied learning experiences because science can’t be learned by reading and discussion only, but also by hands-on activities.
Flowability and strength properties of high volume of fly ash material on self-compacting concrete
Authors: Wardhono Arie
Published: February 2021

The detail complexity level of the building structure is getting more complicated. The use of a high volume of fly ash self-compacting concrete (HVFA-SCC) with better flowability properties is one alternative to address this problem. This research aims to investigate the strength properties and flowability of a high volume of fly ash self-compacting concrete (HVFA-SCC). The primary materials of HVFA-SCC were Ordinary Portland Cement (OPC), fly ash as OPC replacement material, fine and coarse aggregates. The ratio of OPC to fly ash was 0.500:0.500, 0.475:0.525, and 0.450:0.550. The strength properties were determined based on compressive strength and porosity in hard concrete conditions at 28 days. While the flow abilities were identified conforming slump test and slump flow in fresh concrete condition directly after a mixing process. The results show that the substitution of 0.500 fly ash as shown by the HVFA-SCC-2 specimen gives the best strength properties and flow abilities. The highest strength was achieved at 32.4 MPa with a porosity of 0.48 at 28 days-age. The slump and slump flow properties also demonstrate a good flow behavior under EFNARC standard with a slump of 26.1 cm and a slump flow of 656.9 mm. It can be concluded that the 50% substitution ratio of fly ash can replace the role of OPC in HVFA-SCC and improve its strength properties and flow behavior. The use of fly ash also able to overcome the global warming issue regarding OPC production.
The effectiveness of physics learning tools based on discovery model with cognitive conflict approach toward student’s conceptual mastery
Authors: Gunawan G , Kosim K , Ibrahim I , Susilawati S , Syukur A
Published: February 2021

The Discovery learning model with the conflict cognitive approach is a teaching model designed to help students develop thinking skills by involving contradictory problems. The combination of the learning model with this approach means that the stages of the discovery learning model are combined with the learning stages of the cognitive conflict approach. This study aims to measure the effectiveness of discovery model learning tools with a cognitive conflict approach to students’ mastery of concepts. The research was a quasi-experiment with one group pretest and posttest. The population of the study was the students of class 10th grade high school in the city of Mataram with a sample of 65 students. Data collection using the test method. The test instrument used was a mastery of the concept in the form of 25 multiple-choice questions. The data collected were analyzed using the N-Gain score. The results showed that the use of discovery model physics learning tools with the cognitive conflict approach was effective to improve students’ conceptual mastery. The highest increase in concept mastery is in the sub-material of business with the highest cognitive level, namely remembering and understanding.
Antioxydant activity of the silver nanoparticles (AgNPs) synthesized using Nephrolepisradicans extract as bioreductor
Authors: Sutoyo Suyatno , Tukiran  , Khotijah S
Published: February 2021

The silver nanoparticle is a silver metal in nanosize which is currently widely applied in various fields, such as optics, electronics, biology, catalysts, health, food, and the environment. Silver nanoparticles can be synthesized by top-down and bottom-up methods. Bottom-up method can be done by reacting silver nitrate solution with plant extracts or known as green synthesis. This research is aimed to synthesis the silver nanoparticles using the methanolic extracts of Nephrolepisradicansferns as bioreductor and testing their antioxidant activity. The characterization of silver nanoparticles synthesized was carried out using the UV and FTIR spectrophotometer. The antioxidant activity test was carried out using the DPPH method. The results showed that the silver nanoparticles synthesized had an average diameter of 19,194 nm. Based on the IR spectrum, the functional groups that played an important role in the process of synthesis of silver nanoparticles were hydroxyl (OH), carbonyl (C = O) and ether (C-O). The silver nanoparticles had antioxidant activity in the medium category with IC50 of 106.442 ppm. Thus, the silver nanoparticles synthesized had the potential to be developed as antioxidants agent.
Students’ creative thinking skills in biology learning: fluency, flexibility, originality, and elaboration
Authors: Handayani S A , Rahayu Y S , Agustini R
Published: February 2021

This study aimed at analysing junior high school students’ creative thinking skills in biology learning. Creative thinking skills were measured by providing 5 open-ended essays with the indicators of fluency, flexibility, original thinking, and elaboration thinking. The present study used descriptive survey method to obtain quantitative data without special treatment. The research participants were 189 eight-grade students registered in nine public junior high schools in Bangkalan Regency. The results showed that the students’ creative thinking skills were still low at all indicators of creative thinking skills and included in an uncreative category, especially in detailing and producing innovations as well as troubleshooting problems using various approaches. However, their fluency got the best score compared to other indicators even though the classical passing grade was not achieved.
Natural Inhibitors to Increase the Antioxidant Activity of Yacon Tubers Syrup
Authors: Yuanita L , Wikandari P R , Dprastiwi  , Avandi R I , Sabtiawan W B , Sari D A P , Purnama E R , Maulidah E Y
Published: February 2021

Yacon tubers contain various bioactive including flavonoids and phenolic compounds, having antioksidant properties. The aim of the study was to obtain the effect of using natural inhibitors on the antioxidant activity of yacon tubers syrup. Phytochemical tests are used in the determination of flavonoids, phenolic content and antioxidant activity. Total content of phenol and flavonoid were measured by spectrophotometry, while the antioxidant activity was measured by DPPH method. The results showed that the use of natural inhibitors affects the antioxidant activity of yacon tuber syrup. The content of flavonoids and phenolic compounds in yacon syrup using natural inhibitors were 148.093±3.973 and 1244.595±67.672 ppm, significantly different from yacon syrup without inhibitors 100.923±9.277 and 978.912±54.223ppm. Antioxidant activity of syrup with natural inhibitors were 52.888% and IC50: 6.383, while yacon syrup without inhibitors were 24.388% and IC50: 11.180.
Laceability on a class of line graph of cartesian product of graphs
Authors: Neelannavar Shashidhar shekhar , Girisha A
Published: February 2021

Determining Hamiltonian path connectivity relationship among the nodes of the network increases its optimal connectivity. If a and b are nodes in a graph G so that d(a,b) = t and then P is a non-Hamilton path in G. G is referred to as K
+
r hypo -edge -Hamilton-t -laceable if P + re forms Hamilton path joining a and b, for each t for 1 ⩽ t ⩽ diamG. In this research article we investigate the hypo-edge-Hamilton laceability of line graph of Cartesian product of paths and cycles. Also we discuss the results on Cartesian product of path and wheel.
Semantic role labelling using transfer learning model
Authors: Nair Archana M , Bindu K R
Published: February 2021

Semantic role labelling plays a major role in determining the main predicate and related arguments and its relationship to the predicate. These arguments identify the semantic roles in a sentence such as agent, goal, result, etc. Many approaches have been made to perform the task of semantic role labelling. Many recent works incorporated neural networks making use of syntactic features of the given text such as part of speech tags, POS tagged dependency tree, etc. Other works included the use of BERT along with LSTM and MLP to create semantic role labeling models. In this work, BERT model has been fine tuned to be used as a classifier to detect the main predicate, arguments of the predicate and also the relationship arguments maintain with the predicate in the sentence. Using BERT to build a simple classifier creates an efficient semantic role labelling model. Model performance was assessed using metric accuracy, precision, recall and F1 score. This is achieved by comparing the output of each word with the predicted word and labels as well as the arguments in the prediction of the output.
Automatic Segmentation of outer edges of retinal layers in OCT scan images using Eikonal Equation
Authors: Mittal Praveen
Published: February 2021

Optical coherence tomography (OCT) is a non-invasive diagnostic method specially used in retinal as it the most sensitive organs among human parts. It uses low coherence light waves to render the cross-section view of the retina in micrometer resolution. In the analysis of a retinal anomaly, the sectional visualization proves to be an immensely powerful mechanism. For prior detection of retinal diseases, slicing of the required portion from the dataset images into definite layers is a necessary step. It helps to map and measure their thickness. These measurements help with the diagnosis and provide proper guidance for the treatment of diseases of the retina.In this work, we are taking an account of calculating the precise geodesic distance approach for the OCT segmentation of images in two-dimensional spaces. The technique we are using takes into account horizontal and vertical intensity variation and get onto a weighted geodesic distance. By applying the fast marching approach on the Eikonal equation, this work is calculating the shortest path. Although the proposed Geodesic distance method using the Eikonal equation is a bit complex method it outperforms graph as well as other techniques in portraying precisely the retinal layers.
A Combined Sudoku and Synthetic Colour Image Techniques for Cryptographic Key Generation
Authors: Manikandan C , Sai Siva Satwik K , Smarani T M , Umamaheshwari P
Published: February 2021

The exchange of sensitive digital information has increased significantly in the last decade due to the internet’s growth and availability. More robust encryption techniques were introduced to secure the data-in-transit and data-at-rest. The strength of these encryption algorithms depends on the keys. Keys are generated using Pseudorandom Number Generators (PRNG). The key generation algorithm defines these PRNGs. Although there are many robust key generation algorithms, there is a demand for new key generation algorithms to break hackers’ experience and knowledge. This paper proposed a new key generation algorithm using value generated from sudoku matrices and synthetic color image. 8 × 8 sudoku matrices are generated randomly for each session. These sudoku matrices are solved using backtracking and recursive programming. The solved sudoku matrices are used to extract bits from pixels of the synthetic color image. The extracted bits are then combined to form a key. Further, randomness in the key is tested using the NIST (National Institute of Standards and Technology).
Geospatial Survey Analysis for 3D Field and Building Mapping using DJI Drone and Intelligent Flight Battery
Authors: Zakiyyatuddin Azka , Evita Maria , Srigutomo Wahyu , Meilano Irwan , Djamal Mitra
Published: February 2021

Geospatial industry undergoes revolution for every few years. The industry used total stations, GPS, and robotics for the past mapping method. Now, professionals around the world are using drones for mapping which boast quick data collection times, excellent accuracy, and safe operator experience. However, the method for making a 3D map of field and buildings are different. For making a 3D model of buildings, drone must collect the data of buildings by orbiting each of the building. Surveyor will need more time and effort to make a 3D map of buildings than field in the same quality. Therefore, professionals have to make an effective plan to survey different kinds of region. For this research, we used DJI Phantom 4 Pro which has the intelligent Lithium Ion Polymer Battery with the capacity of 5350 mAh. Using the drone, we used different kinds of grid plans to collect map data of regions with buildings and a sport field in Institut Teknologi Bandung, Indonesia. A 3D modelling software is being used to construct an orthophoto and 3D model of the surveyed region which results error data of 3-5 m. According to this research, we can survey about 111.180 m2 area with 0.045m/px resolution using only one battery by the overlap image of 80% We believe these flight plans can inspire researcher and professionals of geospatial to develop other plans for bigger survey application.
Photogrammetry using Intelligent-Battery UAV in Different Weather for Volcano Early Warning System Application
Authors: Evita M , Zakiyyatuddin A , Srigutomo W , Aminah N S , Meilano I , Djamal M
Published: February 2021

We have developed a new volcano early warning system based on sensor node, internet of things (IoT) and UAV to overcome some problems in Indonesian volcano monitoring system. Data (monitored by sensor node) transmission and communication is managed by the IoT while UAV is used for remote sensing data to complete the system to predict the geological status of the volcano. An intelligent-battery UAV is needed for this purpose which manage the power utilization for field application. First stage of the remote sensing process is volcano region mapping for constructing an orthophoto before it is combined with field sensor data. Therefore, we have conducted a laboratory experiment to map some region in ITB, Bandung in different weather as real volcano condition. We have constructed day, night, sunny and cloudy maps of ITB after some data collected through flight and control plan as real volcano environment. Some grid flight plans were chosen for expected result as well as battery saving for each 5 meters data collection. A 3D software has been used for modelling of the orthophoto construction and resulted in 0 – 8 meters error of 20000 – 24000 m2monitored area. Therefore, this method could be used in real volcano application.
The RCCS Thermal Analysis during the Station Blackout Accident of RDE
Authors: Kusumastuti R. , Sriyono  , Tjahjono Hendro , Setiadipura Topan , Pancoko M.
Published: February 2021

RDE is designed based on HTGR technologies; it has an active, passive and inherent safety system. Defence in depth philosophy is conducted. The heat transferred from the reactor vessel to the structure of the containment is equipment in the RDE has a name is a reactor cavity cooling system (RCCS). During normal operation and protecting the reactor containment structure in the event of failure of all active cooling systems, the RCCS designed to take fulfill this role by preserving the vessel reactor under the maximum allowable temperature. Concerning heat dissipation design, RCCS assessment and resolution are considered as major factors in determining the maximum power level of heat dissipation. Active and passive mode is the equipment on RDE RCCS. This paper discusses the calculation of RCCS thermal analysis during the station blackout (SBO) accident. SBO occurred and the heat removal is conducted by RCCS when all of the active cooling systems were failed. Conditions will be safe if the RPV temperature must be maintained below 65°C. There is no electricity from diesel generator supplied to the primer compressor, it will the SBO accident. The methodology used is based on the calculation mathematical model of the pebble bed modular reactor heat transfer capability of the RCCS in the passive mode. The passive mode works during the failure of active mode, and the heat is released through the cavity by natural convection. The RCCS is capable to withdraw the heat at 50.54 kW per hour and keep the reactor pressure vessel temperature below 65°C at normal operation and below 125°C during the station blackout.
The photothermal effect of polypyrrole modified gold nanoparticles on SKOV-3 cells using SEM and AFM
Authors: Liu C Z , Huang Y X , Zhao C R , Wang Z B
Published: February 2021

Nanotechnology and its application are widely used in the field of life, human exploration of life science has entered the nano level, which is of great significance for exploring the essence of cellular life. This paper explores the changes in the mechanical characteristics of tumor cells after the photothermal effect of nanomaterials. The experiments used AFM and SEM to measure and observe SKOV-3 cells before and after the treatment. It was found that the cell height, morphology, cell adhesion, and Young’s modulus had significantly changed. In the PPy-GNPs+Laser group, the adhesion force value was 3.57±1.25 nN, and Young’s modulus was 27.4±2.47 kPa. From the data, a 53.9% increase in Yong’s modulus of laser test PPy-GNPs as compared with the control group. It shows that the photothermal effect of nanoparticles has an important effect on the changes of cell ultrastructure, which has important significance for explaining the changes of cell physiological functions from the perspective of cell mechanics.
Analysis on magnetic control stud welding device with the open-close Structure
Authors: Zhu L , Wu J H , Kong L C , Ye X D , Wang R C
Published: February 2021

Arc stud welding is widely used to fix joints like studs, screws, pins, or similar elements on various products. The main defects in the process of large diameter stud welding are arc offset and non-uniform melting. In order to solve the problems, which seriously affect the installation strength of stud, the magnetic confinement device with the open-close structure is used to improve the quality of stud welding. An open-close magnetic confinement device suitable for robotic stud welding system is designed to create rotatable magnetic field. Rotating magnetic field can drive arc deflection. The magnetic field produced by magnetic confinement device is simulated. The distribution and intensity of magnetic field is analyzed. The influence of the design parameters of magnetic confinement device on the magnetic field is studied. According to the practicability and the size limitation of the magnetic confinement device, the appropriate parameters are selected. The prototype of the magnetic confinement device is tested by stud welding. The results show that the open-closed magnetic confinement device designed with reasonable parameters has good inhibitory effect on the arc offset.
Effect of Inversion Asymmetry on Quantum Confinement of Dirac Semimetal Cd3As2
Authors: Chou Christopher , Goyal Manik
Published: February 2021

The discovery of the 3D Topological Dirac semimetal Cd3As2 presents a new class of semimetals because of its unique electronic structure and transport properties, demonstrating potential in novel topological devices. Promising properties of Cd3As2 include its topological surface states, ultrahigh electron mobility, and linear band dispersion. We evaluated the effect of inversion asymmetry on quantum confinement of Cd3As2 by measuring its electronic properties with and without hybridization through the quantum transport simulation package Kwant. Due to confinement, Cd3As2 exhibits a similar state to a 3D topological insulator because the transport in the bulk state becomes gapped, causing the surface state to dominate transport similar to 3D topological insulators. Thus, we can compare transport properties and band structure of Cd3As2 with other known 3D topological insulators such as HgTe and (Bi1-x
Sb
x
)2Te3 through the analysis of previous electrostatic gating studies. We observe the lifting of the spin degeneracy due to inversion asymmetry and demonstrate that Cd3As2 provides a promising platform for topological device applications.
Rheological stability enhancement of polyethylene modified bitumen by the addition of paraffin wax
Authors: Xia T , Chen X , Xu J H , Dai J F , Li Y Y
Published: February 2021

The rheological behavior of Polyethylene (PE) modified bitumen is investigated. It is found that a rheological plateau under high temperature presented on the curve of storage modulus (G
*) variation with temperature. By the addition of little wax, the rutting resistance of bitumen/PE blend can be further improved. Moreover, the wax incorporation into bitumen/PE can significantly decrease the starting temperature of rheological plateau to accommodate the actual service temperature of bituminous pavement, making a potential application of PE/wax modified bitumen in pavement engineering. The reason for this rheological property enhancement by wax is explored in terms of phase separation structure and thermal behavior of bitumen/PE blends. Main focus is put on the relationship between PE crystallinity and rheological behavior.
Effect of substrate annealing on wetting behavior and interfacial reaction between Sn-0.7Cu and amorphous Fe84.3Si10.3B5.4 alloy
Authors: Hou B , Wang H Q , Zhang Y P , Wang H Y , Zeng C Y , Wu B Y
Published: February 2021

Wetting behaviors of Sn-0.7Cu on amorphous Fe84.3Si10.3B5.4 substrate and substrates annealed at various temperatures (i.e., 400 °C, 500 °C and 650 °C ) were investigated at 250 °C, 300 °C, 350 °C and 400 °C by the sessile drop method, and the interfacial reaction of Sn-0.7Cu on different Fe84.3Si10.3B5.4 substrates with different annealing treatments were studied by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Obtained results show that at the same soldering temperature, the final equilibrium wetting angle of Sn-0.7Cu on Fe84.3Si10.3B5.4 substrates gradually increases with the increase of annealing temperature. That means the wettability becomes worse and the interfacial reaction becomes weaker. With the increase of soldering temperature from 250 °C to 400 °C, the final equilibrium wetting angle of Sn-0.7Cu on Fe84.3Si10.3B5.4 substrates decreases gradually, suggesting a better wettability.
Structural design and analysis of an automatic pineapple picking and collecting straddle machine
Authors: Guo A F , Li J , Guo L Q , Jiang T , Zhao Y P
Published: February 2021

To maximize economic returns and reduce damages to the fruit and plant, an automatic straddle harvester for pineapples was designed, based on the planting mode and growth characteristics of the pineapple. The machine is composed of a picking manipulator, fruit transport and collection device, continuous track, and control system. The physical characteristics of pineapple fruits were investigated, and the overall structure and size of the automatic pineapple picking and collecting machine were designed based on the growth characteristics and the planting mode of the pineapple plant. SolidWorks was used for virtual modeling and then the different parts were designed based on parameters, such as the dimensions and power of the track chassis. Simulation analysis on the frame base and manipulator revealed that with a cutting sawtooth speed of 1200 r/min the cutting efficiency of the pineapple picking manipulator can reach 1636 plants/hour, i.e., double the manual cutting efficiency.