bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of wave scattering from 2D curved metasurfaces using Floquet and Fourier series expansions
Authors: Khatami Maryam S. , Dehmollaian Mojtaba , Yousefi Leila
Published: April 2021

An efficient technique for calculating the scattering from curved metasurfaces using the extinction theorem in conjunction with the Floquet and Fourier series expansions is presented. Here, we treat the two‐dimensional metasurfaces that have transversal polarizabilities with no variation along the y‐axis. The boundary conditions at the metasurface are given by the generalized sheet transition conditions (GSTCs) whose susceptibilities are given in an arbitrary local coordinate system. First, we use the extinction theorem to provide integral equations of the scattering problem. The integral equations involve the Green's functions, tangential electric and magnetic fields and their normal derivatives in regions above and below the metasurface. Then, we employ the Floquet theorem that gives us the analytical periodic Green's functions of each region. Next, we employ the Fourier theorem to expand the tangential fields in terms of unknown Fourier coefficients. The GSTCs and the integral equations provide equations to be solved for the unknowns. The method can calculate scattering from both periodic and non‐periodic metasurfaces. The technique is used to analyse different applied problems such as carpet cloaking, illusion, and radar echo width reduction. The method is fast and accurate and can efficiently treat metasurfaces with electrically large curved geometries with dimensions as large as 120 times the wavelength.
Microwave intracavitary applicator using 434 MHz conformal patch antennas for hyperthermia treatment of gynaecological cancers
Authors: Rajendran Tharrini , Arunachalam Kavitha
Published: April 2021

Feasibility of a 434 MHz microwave intracavitary applicator with conformal patch antennas is presented for hyperthermia treatment of gynaecological cancers. 3D numerical modelling was used to design a 434 MHz resonant conformal rectangular patch on a cylindrical alumina substrate. A conformal array applicator designed using four conformal patch antennas was evaluated in muscle tissue phantom. Applicator measurements indicated that the conformal patch resonated at 434 MHz with power reflection coefficient ρ < −35 dB, penetration depth of 12 mm at 434 MHz and −10 dB bandwidth >40 MHz. Normalised power deposition in the applicator transverse (XY) plane yielded 25% Effective Field Size (EFS) of 180 and 175 mm2 in simulation and measurement, respectively, for excitation of single conformal patch. The 25% EFS for excitation of two antennas was 500 and 510 mm2 in simulation and measurement, respectively. Simulations and measurements suggest that the 434 MHz intracavitary microwave applicator with conformal patch antennas could be used to deliver adjustable and localised power deposition at the target sparing the surrounding healthy tissues.
Understanding the enhanced electrorheological effect of reduced graphene oxide‐supported polyaniline dielectric nanoplates by a comparative study with graphene oxide as the support core
Authors: Yuan Jinhua , Wang Yudong , Xiang Liqin , Zhao Xiaopeng , Yin Jianbo
Published: April 2021

Graphene has attracted scientific interest as a substrate or additive for developing high‐performance stimuli‐responsive materials. Research on graphene‐based polymer dielectric composites has shown an enhanced electroresponsive electrorheological (ER) effect. However, the mechanism behind the enhanced electroresponse is still incompletely understood. Here, an investigation was performed into dielectric polarization and the ER effect of reduced graphene oxide‐supported polyaniline nanoplates by comparing them with pure granular polyaniline and graphene oxide‐supported polyaniline nanoplates based on dielectric spectroscopy and rheologic analysis. We discovered that both anisotropic morphology and electrical properties have dominant roles in the enhanced ER effect of reduced graphene oxide‐supported polyaniline nanoplates, whereas only anisotropic morphology has a dominant role in the enhanced ER effect of graphene oxide‐supported polyaniline nanoplates. The analysis also showed that reduced graphene oxide‐supported polyaniline nanoplates have a good ER response to both DC and AC electric field actions in the wide shear rate region. This is highly desirable for practical engineering applications. Therefore, the analysis reveals the reason for the enhanced ER effect of reduced graphene oxide‐supported polyaniline nanoplates and also may provide a guide for designing high‐performance ER materials for practical engineering applications by combining the advantages of conducting a reduced graphene oxide core and ER active shell.
Seamless switching power sharing control method in a hybrid DC‐AC microgrid by the isolated two‐stage converter based on SST
Authors: Li Yue , Peng Yonggang , Wang Xiaoming
Published: April 2021

To facilitate the application of various renewable generations as well as diversified loads, hybrid DC/AC microgrids have aroused widespread interest; however, direct access of different types of sources and loads to the utility through multiple converters may be inefficient. In addition, with the complexity growth of the system, the stable and efficient operation puts forward new requirements for the isolation protection and more intelligent control. Facing these problems, the isolated two‐stage converter topology based on solid state transformer (SST) is designed and the automatic seamless switching power sharing control strategy is proposed. The proposed topology replaces the conventional passive transformer with dual‐active‐bridge converter (DABC) to realize voltage matching and galvanic isolation for higher controllability and less volume occupation. Constant ratio control method is adopted for DABC to operate as an ideal DC transformer. Further, AC frequency and DC voltage are measured as characterizations of power level to adjust the transferred power of the converter. Through the non‐directional strategy, bidirectional power support and decentralized cooperation are realized, and the capacity and sensitivity of microgrids are considered. The stability of the proposed control strategy is analyzed and the feasibility is verified by several real‐time hardware‐in‐loop experiments.
Parameter estimation and CRB analysis of 1‐bit colocated MIMO radar
Authors: Liu Bingfan , Chen Baixiao , Yang Minglei
Published: April 2021

The increasing demand for low‐cost and low‐power radars has led to the emergence of 1‐bit sampling technology. 1‐bit sampling technology is introduced in a multiple‐input and multiple‐output (MIMO) radar that has many advantages such as a high degree of freedom and flexible transmit beam pattern. The authors’ theoretical derivation shows that after 1‐bit quantisation, the received signal can be expressed as a linear combination of infinite components, which include the original component and high‐order components that can be regarded as interference terms. On this basis, the signal‐to‐noise‐ratio (SNR) loss after 1‐bit sampling at a low SNR is 1.96 dB. Furthermore, the Cramér‐Rao bound (CRB) of a MIMO radar with 1‐bit sampling is derived. In the derivation, the concept of 1‐bit equivalent noise is proposed. At low SNRs, the equivalent noise power is π/2 (1.96 dB) times the original noise power, which is consistent with a previous derivation. Numerical simulations showed the feasibility of traditional algorithms for a MIMO radar with 1‐bit sampling and the correctness of the authors’ derivation.
Improving the efficiency of gas exchange during alimentary biocorrection of the nutritional status of students and teachers of an engineering university
Authors: Rodionova Natalya , Syromyatnikov Michael , Popov Evgeny , Pozhidaeva Ekaterina , Pastukhova Natalya , Rodionov Alexander
Published: April 2021

The results of studies of alimentary correction of the efficiency of gas exchange in the lungs by the example of students and teachers of an engineering university with daily use of foods with known bio-correcting properties: 3.5 g of wheat germ oil (WGO), 50 g of wheat germ meal cake (WGMC), are presented 6.5 g of concentrated tissue fish oil (CTFO) and their combinations with the biomass of the consortium of lacto- and bifidobacteria (10 g). The efficiency of gas exchange processes was evaluated based on the analysis of the respiratory coefficient, the concentration of carbon dioxide (CO2) and oxygen (O2) in the exhaled gas mixture was determined using a TESTO-310 gas analyzer, an MDG-1201 capnograph, the values of which were recorded before and after daily use of the studied products during 30 days. The experimental group consisted of volunteers – teachers and university students aged 16 to 65 years, divided into 3 age groups: 16-24, 25-44 and 45-65 years old. It was established that the most effective antihypoxic drug is WGMC, in all age groups, the increase in average RR values amounted to 0.041 units, and 4.8% relative to the initial values. When using WGO, the change in RC was 0.032, an increase compared to baseline – 3.7%. In the 1st, 2nd and 3rd age groups, the average change in RC was: 0,031, 0,036 and 0,043 units, relative to the initial indicators, the increase was 3.5, 4.2 and 5.0%, respectively. It is proved that the combination of the studied biocorrector with the active forms of probiotic microorganisms provides a more active antihypoxic effect for all the studied products in all age groups. The effectiveness of the WGO was increased, the increase in RC was 0.049 units, for CTFO – 0.024 units. The growth of RC relative to the initial values was 5.7 and 2.9%, respectively. The synergism of the action of biocorrectors in combination with probiotics, by age groups amounted to – 0.035, 0.033 and 0.038 units, which is 4.1, 3.8 and 4.5% relative to the initial indicators.
Seasonal growth of sprouts in introduced three plants under extra arid conditions of Southern Uzbekistan
Authors: Yoziev Lutfullo , Samatova Shohista , Buronova Muhayyo
Published: April 2021

The article presents the results of the study of the growth dynamics of the sprouts of 52 woody plants, representing 19 genera from 5 families, of different geographical origin. In the conditions of Southern Uzbekistan, the growth of introduced species takes place in early, more favorable spring terms and is characterized by higher intensity. With the onset of the extreme period (early June), the vast majority of species stop growing. Most species studied have a short growth period. The strategy of adaptation of introduced plants is expressed in reduction of growth period and increase of its rate.
Participation of dopaminergic system in the dynamics of behavioral reactions of aging rats of both sexes under daily testing in the open field
Authors: Birukova Elena , Khusainov Denis , Chajka Andrew , Tribrat Natalya , Dzhemalyadinova Zera , Dmitrenko Natalia , Chornobay Svitlana
Published: April 2021

Under daily testing of aging rats of both sexes in the open field a slow lowering of motion activity is observed: by the 6th day of the experiment the passed distance of male rats reduces by 41% (р≤0.01), and of female rats – by 46% (р≤0.05) in comparison to the background values. The blockade of monoamine oxidase-B (МАО-В) by selegiline (intraperitoneal Introduction of 5 mg/kg one hour before testing) does not significantly change the orientation and intensity of this process, but probably contribute to the formation of a more comfortable psycho-emotional state of the animals. Consequently, the central dopamine cannot prevent from the motion activity lowering process of aging rats under daily testing, at least, in the frames of the experiment method used in this research. We obtained the evidence in favor of the fact that the suppression of the motion activity under daily testing is rather connected with the animals’ loss of motivation for research than with the growing anxiety.
New inverse DEA models for budgeting and planning
Authors: Sayar Tahere , Ghiyasi Mojtaba , Fathali Jafar
Published: April 2021

Data envelopment analysis (DEA) measures the efficiency score of a set of homogeneous decision-making units (DMUs) based on observed input and output. Considering input-oriented, the inverse DEA models find the required input level for producing a given amount of production in the current efficiency level. This article proposes a new form of the inverse DEA model considering income (for planning) and budget (for finance and budgeting) constraints. In contrast with the classical inverse model, both input and output levels are variable in proposed models to meet income (or budget) constraints. Proposed models help decision-makers (DMs) to find the required value of each input and each output’s income share to meet the income or budget constraint. We apply the proposed model in the efficiency analysis of 58 supermarkets belonging to the same chain. However, these methods are general and can be used in the budgeting and planning process of any production system, including business sectors and firms that provide services.
A Question of Timing: 10-year Retrospective Analysis on the Use of Antenatal Steroids for Imminent Preterm Birth
Authors: Matlac Dieter , Jonassen Sinje , Fortmann Mats Ingmar , Rody Achim , Bossung Verena
Published: April 2021

Objective Antenatal steroids improve the neonatal outcome if they are
administered within a therapeutic window of seven days before preterm birth.
The aim of this study was to evaluate the timing of antenatal steroids for
imminent preterm birth at a single center in Germany.

Material and Methods A 10-year retrospective analysis of 843 preterm
births between 24/0 and 33/6 weeks was performed from
January 2008 to December 2017 at a German university hospital. We evaluated
the timing of antenatal steroids according to the indication for their
application. Descriptive statistics and binomial regression were performed
to analyze factors influencing the timing of antenatal steroid
administration.

Results Of 843 preterm births below 34 weeks included in our study,
752 pregnant women received antenatal steroids (89.2%). Only
301/843 women (35.7%) gave birth within the optimal window
of 7 days after antenatal steroids. 91/843 women (10.8%) did
not receive steroids. 130/843 women (15.4%) only received
one dose, 76/843 (9.0%) gave birth within 8 to 14 days, and
245/843 (29.1%) more than 14 days later. In a binomial
regression model, preterm premature rupture of membranes (OR 3.40,
95% CI 1.81 to 6.39, p<0.001), fetal growth restriction (OR
3.27, 95% CI 1.63 to 6.58, p=0.001), and preeclampsia (OR
2.83, 95% CI 1.37 to 5.83, p=0.005) were positively
associated with optimal timing.

Conclusion Two thirds of women with preterm birth before 34 weeks
received antenatal steroids outside the optimal therapeutic window. Further
research is needed to achieve an optimal effect of antenatal steroids on
neonatal outcome and to reduce untimely as well as unnecessary
interventions.
Collaborative decision-making of wind-storage combined power generation system based on a variety of improved evaluation methods
Authors: Liu Jicheng , Bao Hongyan
Published: April 2021

Wind power enterprises and energy storage companies have combined to form a wind-storage supply chain. Choosing a wind-storage combined power generation system will help companies make faster and better decisions and increase the value of cooperation in the wind-storage supply chain. Based on industry characteristics, 22 indexes that affect the collaborative decision-making of wind-storage combined power generation systems are selected, and an index evaluation system based on the interpretative structure model is designed. The entropy method is used to determine the index weight. Three collaborative decision-making models are designed, namely, a collaborative decision-making model based on the entropy weight method–fuzzy comprehensive evaluation method, a collaborative decision-making model based on the entropy method–TOPSIS, and a collaborative decision-making model based on fuzzy TOPSIS. The reliability of the model is verified through comparative analysis. At the same time, development suggestions in six aspects are put forward. This article provides a reference for collaborative decision-making between wind power enterprises and energy storage companies in the wind-storage supply chain.

At the request of the authors, this article is being retracted effective 2 June 2021.
A new model for developing sustainable green industries: A case study of Mashhad, Iran
Authors: Faghani Kondori Pegah , Mostafaeipour Ali , Sadegheih Ahmad , Zare Mehrjardi Yahya , Vahdatzad Mohammad Ali
Published: April 2021

The industrial sector is one of the major sources of environmental pollution. Industrial processes can generate many types of pollution including water pollution, soil pollution, air pollution, and noise pollution. With the expansion of industrial towns across Iran, this country has seen an increase in the amount of industrial pollutants. To tackle this issue, it is necessary to identify the factors that affect the development of green industries. This study aimed to identify and model the factors that influence the development of green industries and determine government policies and regulations that could be effective in reducing industrial pollution. First, the existing literature was reviewed, and 45 factors that can potentially affect the development of green industries were identified. Then the subject was further explored by designing and distributing a questionnaire with focus on a specific case, which was Mashhad industrial zone. The software SmartPLS was used to evaluate the fit of the developed model and then the structural equation modeling technique was employed to construct a model for the influential factors. The results showed that among the studied variables, seven variables have a significant impact on the development of green industries. The factor with the greatest effect on the development of green industries was found to be the “current situation of the industry,” followed by “government incentives,” “managerial commitment,” “market for green products,” “competition strategies,” “government oversight,” and “political affairs,” respectively.
Ecoagriculture for a Sustainable Food Future
Authors: Chalmer Nicole
Published: April 2021

Global food security is dependent on ecologically viable production systems, but current agricultural practices are often at odds with environmental sustainability. Resolving this disparity is a huge task, but there is much that can be learned from traditional food production systems that persisted for thousands of years.

Ecoagriculture for a Sustainable Food Future describes the ecological history of food production systems in Australia, showing how Aboriginal food systems collapsed when European farming methods were imposed on bushlands. The industrialised agricultural systems that are now prevalent across the world require constant input of finite resources, and continue to cause destructive environmental change.

This book explores the damage that has arisen from farming systems unsuited to their environment, and presents compelling evidence that producing food is an ecological process that needs to be rethought in order to ensure resilient food production into the future.

Cultural sensitivity
Readers are warned that there may be words, descriptions and terms used in this book that are culturally sensitive, and which might not normally be used in certain public or community contexts. While this information may not reflect current understanding, it is provided by the author in a historical context.
Experimental and numerical analysis of Tm2+ excited-states dynamics and luminescence in CaX
2 (X = Cl, Br, I)
Authors: Plokker M P , van der Knijff I C , de Wit A V , Voet B , Woudstra T , Khanin V , Dorenbos P , van der Kolk E
Published: April 2021

The prospect of using Tm2+-doped halides for luminescence solar concentrators (LSCs) requires a thorough understanding of the temperature dependent Tm2+ excited states dynamics that determines the internal quantum efficiency (QE) and thereby the efficiency of the LSC. In this study we investigated the dynamics in CaX
2:Tm2+ (X = Cl, Br, I) by temperature- and time-resolved measurements. At 20 K up to four distinct Tm2+ emissions can be observed. Most of these emissions undergo quenching via multi-phonon relaxation below 100 K. At higher temperatures, only the lowest energy 5d–4f emission and the 4f–4f emission remain. Fitting a numerical rate equation model to the data shows that the subsequent quenching of the 5d–4f emission is likely to occur initially via multi-phonon relaxation, whereas at higher temperatures additional quenching via interband crossing becomes thermally activated. At room temperature only the 4f–4f emission remains and the related QE becomes close to 30%. Possible reasons for the quantum efficiency not reaching 100% are provided.
Supersolid-like states in a two-dimensional trapped spin–orbit-coupled spin-1 condensate
Authors: Adhikari S K
Published: April 2021

We study supersolid-like states in a quasi-two-dimensional trapped Rashba and Dresselhaus spin–orbit (SO) coupled spin-1 condensate. For small strengths of SO coupling γ (γ ⪅ 0.75), in the ferromagnetic phase, circularly-symmetric (0, ±1, ±2)- and (∓1, 0, ±1)-type states are formed where the numbers in the parentheses denote the angular momentum of the vortex at the center of the components and where the upper (lower) sign correspond to Rashba (Dresselhaus) coupling; in the antiferromagnetic phase, only (∓1, 0, ±1)-type states are formed. For large strengths of SO coupling, supersolid-like superlattice and superstripe states are formed in the ferromagnetic phase. In the antiferromagnetic phase, for large strengths of SO coupling, supersolid-like superstripe and multi-ring states are formed. For an equal mixture of Rashba and Dresselhaus SO couplings, only a superstripe state is found. All these states are found to be dynamically stable and hence accessible in an experiment and will enhance the fundamental understanding of crystallization onto radially periodic states in solids.
Conversion coefficients from absorbed dose to tissue to the newly proposed ICRU/ICRP operational quantities for radiation protection for beta reference radiation qualities
Authors: Behrens Rolf
Published: April 2021

The International Commission on Radiation Units and Measurements (ICRU) has, jointly with the International Commission on Radiological Protection (ICRP), recently proposed a set of new operational quantities for radiation protection in ICRU report 95. ICRU/ICRP supplied conversion coefficients for mono-energetic betas but not for beta reference radiation qualities defined by the International Organization for Standardization (ISO) in ISO 6980. Therefore, in this work, conversion coefficients from absorbed dose to tissue at a depth of 0.07 mm in a slab phantom to the newly proposed operational quantities are determined for beta reference radiation qualities. Finally, the impact of the newly proposed quantities on primary and calibration laboratories and on users and manufacturers of dosemeters is investigated, the latter by having a close look at the expected change of the response of dosemeters.
Targeted defect analysis in VCSEL oxide windows using 3D slice and view
Authors: Sun X , Rickard W D A , Ironside C N , Kostakis I , Missous M , Powell D , Anjomshoaa A , Meredith W
Published: April 2021

We report on high resolution analysis of vertical cavity surface emitting lasers (VCSELs) to detect and assess defects in sub-surface layers. We employ a focussed ion beam scanning electron microscope (FIB-SEM) to sputter and image successive cross sections (slice and view technique) in order to produce a 3D reconstruction of the oxide aperture region. High resolution images and measurements of the multilayers and oxide apertures of VCSEL devices were obtained. The process took ∼2.5 h and produced over 270 slice SEM images for a device volume of approximately 13.2 × 16.0 × 13.8 μm3, with a voxel size of 50 nm. On-wafer, single mode VCSEL devices with high and low output powers were analysed to compare their oxide apertures and distributed Bragg reflector (DBR) layer structures. It was found that the low output power VCSEL had DBR layer defects and a 41.8% reduction of effective oxide aperture area, explaining the lower power obtained. The results provide evidence that oxide aperture area and structural defects are major factors that affect the optical output power of VCSEL devices. Outcomes in this work show FIB-SEM slice and view is a valuable method for 3D reconstruction of VCSEL devices, which enables top view, cross-sectional view and angled view of the whole device region as well as designated structures such as oxide aperture or structural defects in various layers. This work demonstrates a promising technique with high resolution (50 nm) 3D imaging for analysis of complex semiconductor devices.
Ultrarelativistic electrons in counterpropagating laser beams
Authors: Lv Q Z , Raicher E , Keitel C H , Hatsagortsyan K Z
Published: April 2021

The dynamics and radiation of ultrarelativistic electrons in strong counterpropagating laser beams are investigated. Assuming that the particle energy is the dominant scale in the problem, an approximate solution of classical equations of motion is derived and the characteristic features of the motion are examined. A specific regime is found with comparable strong field quantum parameters of the beams, when the electron trajectory exhibits ultrashort spike-like features, which bears great significance to the corresponding radiation properties. An analytical expression for the spectral distribution of spontaneous radiation is derived in the framework of the Baier–Katkov semiclassical approximation based on the classical trajectory. All the analytical results are further validated by exact numerical calculations. We consider a non-resonant regime of interaction, when the laser frequencies in the electron rest frame are far from each other, avoiding stimulated emission. Special attention is devoted to settings when the description of radiation via the local constant field approximation fails and to corresponding spectral features. Periodic and non-periodic regimes are considered, when lab frequencies of the laser waves are always commensurate. The sensitivity of spectra with respect to the electron beam spread, focusing and finite duration of the laser beams is explored.
Dependence of the polytropic index of plasma on magnetic field
Authors: Kim June Young , Go Geunwoo , Hwang Y S , Chung Kyoung-Jae
Published: April 2021

Determination of the polytropic index of plasma in a magnetic field provides description of plasma physics ranging from laboratory plasma in the Earth to black hole in the Universe. Accordingly, a lot of efforts have been devoted to revealing the dependence of polytropic index of plasma on magnetic field. A recent experiment performed in a magnetic nozzle reported the dependency of the polytropic index on the magnetic field strength in that the polytropic index changes from 5/3 to unity with decreasing the magnetic field strength. In this letter, we show that the polytropic index of plasma does not depend on magnetic field if the radial electric field is sustained. The polytropic index is measured to be close to 2, higher than the previously reported value, regardless of the change in the strength and configuration of magnetic field.
Structural, electronic and optical characterization of Eu
3+/Dy
3+ single and co-doped Mg2P2O7 phosphors
Authors: Mahajan Rubby , Prakash Ram , Choudhary R. J. , Phase D. M.
Published: April 2021

Eu3+/ Dy3+ single and co-doped magnesium pyrophosphate phosphors were synthesized via solution combustion route. The resulted phosphor has a monoclinic crystal structure with space group B21/c. The lattice parameter of the sample is refined using ‘Full Prof software’. x-ray photoemission spectroscopy (XPS) result reveals that dysprosium and europium present in a trivalent valence state. Valence band spectra (VBS) result indicates that 6 features present in a single doped sample and 8 features present in a co-doped sample. The photoluminescence studies reveal that the combination of Eu3+ and Dy3+ emissions give tuneable emission from red to pink to yellowish-white under UV excitation. The energy transfer mechanism from Dy3+ to Eu3+ is confirmed from photoluminescence spectra and life time curves. The optical band gap of the prepared samples is obtained to be in the range of 5.02–5.40 eV. The synthesized material has conventional application in solid-state lighting under UV-excitation.
Spectroscopic characterization of thermally evaporated oxovanadium(IV) tetraphenylporphyrin thin films
Authors: Makhlouf M M , Farooq M U , Ataalla Nahla N , Afifi Mohamed B
Published: April 2021

Thin films of oxovanadium(IV) tetraphenylporphyrin (VOTPP) were prepared on quartz substrates by using thermal evaporation technique. The surface morphology and x-ray diffraction analysis of the VOTPP thin films were investigated. The micrographs of atomic force microscope of the films reveled nanostructure formation. The spectroscopic measurements of the transmittance and reflectance for VOTPP films were recorded in the spectrum range 190 –2000 nm, and from which many optical constants such as refractive index, extinction index and dielectric constant were determined. The absorption spectrum of VOTPP film showed an intense Soret band, two electronic quasi-states (Q-band) and two other bands (N and L) extended over the UV–Vis spectral region. The type of electronic transition bands of VOTPP films showed indirect allowed. The values of optical energies band-gaps were determined to be 1.89, 2.15 and 2.61 eV, in addition to Urbach tail energy was 0.044 eV. Furthermore, Wemple-DiDomenico model was applied to a normal dispersion region of the refractive index spectrum in order to extract many dispersion parameters such single oscillator energy, dispersion energy, infinite dielectric constant and lattice dielectric constant. The present spectroscopic results reveals that the thin films of VOTPP could be utilized as promising absorbing layers in energy conversion devices.
A three-dimensional vertex model for Drosophila salivary gland invagination
Authors: Durney Clinton H , Feng James J
Published: April 2021

During epithelial morphogenesis, force generation at the cellular level not only causes cell deformation, but may also produce coordinated cell movement and rearrangement on the tissue level. In this paper, we use a novel three-dimensional vertex model to explore the roles of cellular forces during the formation of the salivary gland in the Drosophila embryo. Representing the placode as an epithelial sheet of initially columnar cells, we focus on the spatial and temporal patterning of contractile forces due to three actomyosin pools: the apicomedial actomyosin in the pit of the placode, junctional actomyosin arcs outside the pit, and a supracellular actomyosin cable along the circumference of the placode. In an in silico ‘wild type’ model, these pools are activated at different times according to experimental data. To identify the role of each myosin pool, we have also simulated various in silico ‘mutants’ in which only one or two of the myosin pools are activated. We find that the apicomedial myosin initiates a small dimple in the pit, but this is not essential for the overall invagination of the placode. The myosin arcs are the main driver of invagination and are responsible for the internalization of the apical surface. The circumferential actomyosin cable acts to constrict the opening of the developing tube, and is responsible for forming a properly shaped lumen. Cell intercalation tends to facilitate the invagination, but the geometric constraints of our model only allow a small number of intercalations, and their effect is minor. The placode invagination predicted by the model is in general agreement with experimental observations. It confirms some features of the current ‘belt-and-braces’ model for the process, and provides new insights on the separate roles of the various myosin pools and their spatio-temporal coordination.
Probing the entropic uncertainty bound and quantum correlations in a quantum dot system
Authors: Haseli Soroush , Haddadi Saeed , Pourkarimi Mohammad Reza
Published: April 2021

The uncertainty principle is one of the most comprehensive and fundamental concepts in quantum theory and it states that it is not possible to simultaneously measure two incompatible observables with high accuracy. In particular, we show that the entropic uncertainty relation that uses quantum memory is one of the most useful entropic uncertainty relations. In this work, we consider a quantum dot system as a solid-state system which is in the thermal regime, and we then probe the quantum correlations and the quantum-memory-assisted entropic uncertainty bound in this type of system. Interestingly, our results show that there are some system parameters that can be adjusted to suppress the entropic uncertainty bound and improve quantum correlations.
Non-Hermitian Kitaev chain with complex periodic and quasiperiodic potentials*
Authors: Jiang Xiang-Ping , Qiao Yi , Cao Junpeng
Published: April 2021

We study the topological properties of the one-dimensional non-Hermitian Kitaev model with complex either periodic or quasiperiodic potentials. We obtain the energy spectrum and the phase diagrams of the system by using the transfer matrix method as well as the topological invariant. The phase transition points are given analytically. The Majorana zero modes in the topological nontrivial regimes are obtained. Focusing on the quasiperiodic potential, we obtain the phase transition from the topological superconducting phase to the Anderson localization, which is accompanied with the Anderson localization–delocalization transition in this non-Hermitian system. We also find that the topological regime can be reduced by increasing the non-Hermiticity.
Exact solution of an integrable quantum spin chain with competing interactions*
Authors: Wang Jian , Qiao Yi , Cao Junpeng , Yang Wen-Li
Published: April 2021

We construct an integrable quantum spin chain that includes the nearest-neighbor, next-nearest-neighbor, chiral three-spin couplings, Dzyloshinsky–Moriya interactions and unparallel boundary magnetic fields. Although the interactions in bulk materials are isotropic, the spins nearby the boundary fields are polarized, which induce the anisotropic exchanging interactions of the first and last bonds. The U(1) symmetry of the system is broken because of the off-diagonal boundary reflections. Using the off-diagonal Bethe ansatz, we obtain an exact solution to the system. The inhomogeneous T–Q relation and Bethe ansatz equations are given explicitly. We also calculate the ground state energy. The method given in this paper provides a general way to construct new integrable models with certain interesting interactions.
Quantifying plasmon resonance and interband transition contributions in photocatalysis of gold nanoparticle*
Authors: Dong Liang , Zhang Chengyun , Yan Lei , Zhang Baobao , Chen Huan , Mi Xiaohu , Fu Zhengkun , Zhang Zhenglong , Zheng Hairong
Published: April 2021

Localized surface plasmon has been extensively studied and used for the photocatalysis of various chemical reactions. However, the different contributions between plasmon resonance and interband transition in photocatalysis has not been well understood. Here, we study the photothermal and hot electrons effects for crystal transformation by combining controlled experiments with numerical simulations. By photo-excitation of NaYF4 : Eu3+ @Au composite structure, it is found that the plasmonic catalysis is much superior to that of interband transition in the experiments, owing to the hot electrons generated by plasmon decay more energetic to facilitate the reaction. We emphasize that the energy level of hot electrons plays an essential role for improving the photocatalytic activity. The results provide guidelines for improving the efficiency of plasmonic catalysis in future experimental design.
Determinant Factors and Adaptation Features of Mobile Personalized Learning System
Authors: Hamzah Almed
Published: April 2021

The mobile learning field is grown and enhanced to a more sophisticated platform for the last decades. It quickly becomes pervasive among educational stakeholders. Nowadays, both students and teachers are familiar with mobile devices to complete their tasks and assignments. A personalized system is one of the features contributing to the mobile learning system’s ease and effectiveness. This paper aims to identify the determinant factors and adaptation features from the previous works in this field. There are 30 papers to be included in the analysis using a coding strategy. The result elicits some determinant factors, including prior knowledge in using mobile devices, the ability to access the technology, and the existence of guidance from an expert. Also, several common adaptation features include user preferences, learning behavior, performance, and mobile-specific adaptation features such as device characteristics and content metadata. Study limitations and future directions are also discussed.
Network Quality Comparison 4g LTE X And Y in Campus UMSU
Authors: Harahap Partaonan , Pasaribu Faisal Irsan , Siregar Chandra A
Published: April 2021

Long Term Evolution (LTE) the fourth generation (4G) cellular network technology. This LTE speed in data transfer speed reaching 100 Mbps on the side downlink and 50 Mbps on the uplink side. Growth in the number of service users telecommunication in Medan City causes a decrease in network quality, especially 4G LTE technology. By doing a driving test, the area can be found where a system’s signal strength aims to increase the signal quality. Benchmark (comparison) of operator service quality 4G LTE is done by measuring, comparing, and analyzing network quality (performance) of two 4G LTE operators around Muhammadiyah University of North Sumatra. Total operator throughput value X is only 0 > 3 Mbps while the Y operator is 0 > 30 Mbps. The low throughput value is caused by high user traffic during the day. The incidence of low throughput on the Muhammadiyah University of North Sumatra campus coincides with active learning with many students using data services.
Prediction formula development of power transformer no-load noise
Authors: Pramono W B , Wijaya F D , Hadi S P
Published: April 2021

Power transformer noise is one of the contributors to noise pollution in the environment. The dominant component of power transformer noise is no-load noise, which is a noise that appears when a power transformer is connected to a voltage source and is not connected to other electrical loads. The amount of no-load noise must be predicted at the design stage so that the noise does not exceed consumers’ standards or criteria. In this study, the prediction of no-load noise was conducted involving rated power, magnetic flux density, and geometry factor. Based on the measurement results from industrial testing and the multiple linear regression method, no-load noise prediction formula results with better accuracy are obtained.
The development of universal design principles for appropriate technology in small and medium enterprises (SMEs)
Authors: Rahman Taufik , Widyanti Ari , Yassierli
Published: April 2021

The Indonesian government has considered appropriate technology (AT) as a cost-effective strategy to increase productivity, including for farmers in processing agricultural commodities. However, its acceptance and effectiveness still need to be improved so that AT can be used for the general population. The existing AT designs seem to fail in considering the characteristics and capabilities of their users. This paper proposed expanding universal design principles for AT in small and medium enterprises (SMEs). After conducted random observation and interviews with SMEs in Subang Area, this study refers to relevant literature studies from various previous studies. This study’s results are new universal design principles: flexibility in use, practicability, ease of service, perceptible information, tolerance for error, low physical effort, low energy, adjustability, mobility, and modular and straightforward and intuitive use. A conceptual model proposed in this study describes the relationship among user characteristics, the concept of universal design, and the effectiveness of using appropriate technology.
Analysis of significant parameters the development of rechargeable electric energy storage (REES) national recycle standards
Authors: Dewantoro Auraga , Anggundari Widia Citra , Susmiarni Rika Dwi , Louhenapessy Bendjamin B. , Yopi  , Darmayanti Nur Tjahyo Eka
Published: April 2021

The growth in using battery-based electric vehicles (EV) in the world increased significantly last ten years. This trend was to achieve the global target of reducing the negative impact of conventional vehicles. Simultaneously, in reverse, the waste of Rechargeable Electric Energy Storage (REES) of EV escalated. Sources for REES material were limited, but the demand predicted to mount up in the next decade, so recycling is an option to overcome this problem. However, there are still no standards related to REES recycling of electric vehicles in Indonesia, so preliminary data is required in determining parameters associated with REES recycling standards. The parameters were collected by questionnaire from research-based units or producers in government and private institutions in Indonesia as the baseline of this discussion. The respondents stated that REES recycling has three significant parameters: raw material, process, and product. There were seven parameters in raw material, six parameters of the process, and the product comprises four parameters. Further research and discussion against stakeholders are needed to achieve exemplary implementation of REES recycling standards.
Progression in Designing and Fabrication of Minimum Quantity Lubrication (MQL) System with an Arduino based Controller
Authors: Darsin Mahros , Firdaus M M , Hardiataman I , Qoryah R D H , Sidartawan R , Syuhri A , Hermawan Y , Basuki H A , Djumhariyanto D , Yudistiro D
Published: April 2021

Using cutting fluids in machining with petroleum-based creates health hazards issues to the machining operator and environmental problems due to the waste. One effort to reduce it is by applying minimum quantity lubrication (MQL). This research aims to develop an MQL system with an Arduino controlled based on the previous design. The main hardware was changed, i.e., pump, power supply, nozzle, sensor, and temperature setting changed from 70°C to 150°C. The fluid consumption was measured in machining with a depth of cut of 2.3 mm and 2.5 mm and cutting liquid composition of 3:7 and 7:3 (water to dromus cutting fluid). The calculation showed that cutting fluid consumption is mostly more than 1000 ml/h, or it has not achieved a maximum of 500 ml/h. However, compared to the previous design, it has reduced up to half of the former scenario. From the tool deterioration perspective, the depth of cut of more than 2.0 mm results in severe tool deterioration in the form of chipping. The higher the depth of cut, the intense the tool deteriorated. For the next design, we should add an air compressor in the MQL system and solenoid(s) to regulate the spraying.
Parameterization of Oil Palm Shell Concrete on Numerical Damage Model Based on Laboratory Experiment using Digital Image Correlation
Authors: Hongsen Kiuntoro , Melhan Madelestin , Handika Nuraziz , Sentosa Bastian Okto Bangkit
Published: April 2021

As a country that contributes to 85% of the world’s crude palm oil, Indonesia produces enormous amounts of waste-by-products (ex: oil palm shells, fiber, etc.) with its potential to be processed into other useful products, including construction material substituent. Previous studies have shown that the use of oil palm shell as a concrete aggregate substituent can produce lightweight concrete that achieved the structural concrete strength requirements. Nevertheless, a further robust computational model on OPS concrete towards regular concrete using concrete damage model is to be characterized using finite element code CAST3M. OPS concrete’s parameterization is conducted based on concrete cube compression tests using digital image correlation (DIC). The average modulus of elasticity obtained is similar to lightweight concrete. The compression strength obtained is 20.33 ± 1.19 MPa, and the split-tensile strength is 1.23 ± 0.19 MPa.
Study of biodiesel specifications for heavy-duty gas turbine application
Authors: Amri K , Kismanto A , Solikhah M D , Pratiwi F T , Arisanti A G
Published: April 2021

Implementing a 20% biodiesel blend in diesel fuel (B20) has been launched since January 1th, 2016, and it was increased to 30% (B30) on January 1th, 2020, implemented in all sectors, including power generators. Gas turbines utilized as power generators designed to use natural gas or diesel fuel as fuel. Therefore, a study to use biodiesel blend as fuel in gas turbines was required. A comparative study was conducted to analyze the fuel requirements of General Electric’s (GE) Heavy Duty (HD) Gas Turbine specification compared to either of SNI 7182: 2015 and EN 14214 specifications. An assessment was conducted on samples of two biodiesel quality levels called biodiesel and distilled biodiesel to meet the GE HD Gas Turbine’s requirements. This study indicates that the biodiesel quality standards, both SNI 7182: 2015 and EN 14214, are insufficient to meet the gas turbine fuel specifications of the GE HD gas turbine. It is required a more specific quality standard dedicated to gas turbines. On the other hand, among the two samples, distilled biodiesel fulfills the fuel requirements of GE HD gas turbines and might be utilized as fuel for this type of gas turbine. According to the result of this study, a test run of 100% biodiesel (B100) as gas turbine fuel can be proposed to be implemented immediately.
Analysis of Asphalt Concrete Wearing Course made with Asphalt Polyurethane Modifier
Authors: Anas Muchamad Nurul , Siswanto Henri , Rahardjo Boedi , Taufikkurrahman
Published: April 2021

Modified asphalt is one of several solutions to road damage problems. The purpose of this study was to analyze the effect of adding polyurethane to the asphalt concrete wearing course (ACWC). The analysis method used is the Marshall Parameter analysis. Marshall specimens were prepared with modified polyurethane asphalt. The polyurethane content used is 1% to 4% by weight of asphalt with a range of 1%. The results showed that modified asphalt–polyurethane can improve ACWC performance in terms of stability, flow, VIM, VMA, VFA, and MQ. The best performing polyurethane content in this study was 2%, and usage of polyurethane levels above 3% is not recommended due to having MQ which does not meet the specification requirements.