bluuebunny/crossref_metadata_2025 huggingface dataset:
The Number of Perfect Matchings in (3,6)-Fullerene
Authors: YANG Rui , YUAN Mingzhu
Published: July 2023

A [see formula in PDF]-fullerene is a connected cubic plane graph whose faces are only triangles and hexagons, and has the connectivity [see formula in PDF] or [see formula in PDF]. The [see formula in PDF]-fullerenes with connectivity [see formula in PDF] are the tubes consisting of [see formula in PDF] concentric hexagonal layers such that each layer consists of two hexagons, capped on each end by two adjacent triangles, denoted by [see formula in PDF]. A [see formula in PDF]-fullerene [see formula in PDF] with [see formula in PDF] vertices has exactly [see formula in PDF] perfect matchings. The structure of a [see formula in PDF]-fullerene [see formula in PDF] with connectivity [see formula in PDF] can be determined by only three parameters [see formula in PDF], [see formula in PDF] and[see formula in PDF], thus we denote it by [see formula in PDF], where [see formula in PDF] is the radius (number of rings), [see formula in PDF] is the size (number of spokes in each layer, [see formula in PDF], [see formula in PDF] is even), and [see formula in PDF] is the torsion ([see formula in PDF]). In this paper, the counting formula of the perfect matchings in [see formula in PDF]is given, and the number of perfect matchings is obtained. Therefore, the correctness of the conclusion that every bridgeless cubic graph with [see formula in PDF] vertices has at least [see formula in PDF] perfect matchings proposed by Esperet et al is verified for [see formula in PDF]-fullerene [see formula in PDF].
The Non-Convergence of Steiner Symmetrizations
Authors: WANG Tian , LIN Youjiang
Published: July 2023

In this paper, we demonstrate the existence of iterated Steiner symmetrizations of [see formula in PDF] that does not converge, even if the sequence of directions is dense in the unit sphere.
On Packing Trees into Complete Bipartite Graphs
Authors: PENG Yanling , WANG Hong
Published: July 2023

Let [see formula in PDF] denote the complete bipartite graph of order [see formula in PDF] with vertex partition sets [see formula in PDF] and [see formula in PDF]. We prove that for each tree [see formula in PDF] of order [see formula in PDF], there is a packing of [see formula in PDF] copies of [see formula in PDF] into a complete bipartite graph [see formula in PDF]. The ideal of the work comes from the "Tree packing conjecture" made by Gyráfás and Lehel. Bollobás confirmed the "Tree packing conjecture" for many small trees, who showed that one can pack [see formula in PDF] into [see formula in PDF] and that a better bound would follow from a famous conjecture of Erd[see formula in PDF]s. In a similar direction, Hobbs, Bourgeois and Kasiraj made the following conjecture: Any sequence of trees [see formula in PDF], … , [see formula in PDF], with [see formula in PDF] having order [see formula in PDF], can be packed into [see formula in PDF]. Further Hobbs, Bourgeois and Kasiraj proved that any two trees can be packed into a complete bipartite graph [see formula in PDF]. Motivated by these results, Wang Hong proposed the conjecture: For each tree [see formula in PDF] of order [see formula in PDF], there is a [see formula in PDF]⁃packing of [see formula in PDF] in some complete bipartite graph [see formula in PDF]. In this paper, we prove a weak version of this conjecture.
Comparison of the Arterial PaCO2 Values and ETCO2 Values Measured with Sidestream Capnography in Patients with a Prediagnosis of COPD Exacerbation
Authors: İşat Gökhan , Cimilli Öztürk Tuba , Ecmel Onur Özge , Özdemir Serdar , Ünal Akoğlu Ebru , Tokgöz Akyıl Fatma , Kuzu Okur Hacer
Published: July 2023

Background Aim of this study is to investigate whether end-tidal carbon dioxide (ETCO2) values can be used instead of partial pressure of carbon dioxide (PaCO2) values in guiding treatment, and determining treatment benefits in patients that received a pre-diagnosis of chronic obstructive pulmonary disease (COPD) exacerbation at the emergency department.

Methods This observational prospective study was conducted with patients who presented to the emergency department with the complaint of shortness of breath and were diagnosed with COPD exacerbation. ETCO2 was measured with the sidestream method during blood gas analysis in patients with indications for this analysis. Measurements were repeated at hour 1 after treatment.

Results The study included a total of 121 cases. There was a positive correlation between the PaCO2 and ETCO2 values measured before and after treatment (r = 0.736, p < 0.01 and r = 0.883, p < 0.01, respectively). High ETCO2 values were accompanied by high PaCO2 values. When the measurements before and after treatment were evaluated using the Bland–Altman method, most of the result were within the limits of agreement (−4.9 and +31.4/− 2.6 and +9.4), with mean differences being calculated as 13.2 and 8.4, respectively.

Conclusions Although ETCO2 and PaCO2 were statistically consistent according to the results of our study, due to the high averages of differences between these two parameters, the ETCO2 value has limited clinical use in COPD cases compared to PaCO2. However, high ETCO2 values may indicate that noninvasive mechanical ventilation should be included in the treatment of COPD cases without waiting for the results of blood gas analysis, and they can also be when needed for inpatient treatment.
Ukrainian refugees struggling to integrate into Czech school social networks
Authors: Lintner Tomáš , Diviák Tomáš , Šeďová Klára , Hlado Petr
Published: July 2023

We provide a brief insight into the integration of Ukrainian refugees in school social networks in the Czech Republic following the mass migration caused by the Russian invasion of Ukraine. Our sample contains twelve classrooms with a total of 266 students in grades 5 to 9; 21.05% of the students were of Ukrainian origin. We employed multiplex exponential random graph modelling to assess the level to which Ukrainian refugees were integrated within peer networks, capturing both friendship and exclusion ties. We then employed a meta-analytical procedure to aggregate the results from the individual classrooms and a meta-regression to study the relationship between classroom ethnic composition and the level of integration of Ukrainian refugees. We found social networks to be formed heavily along ethnic lines with strong ethnic homophily in friendship ties and a propensity of the Ukrainian students to both send and receive fewer friendship ties than their Czech classmates. We found no evidence that the Ukrainian students sent or received more exclusion ties than their Czech classmates, suggesting that the Ukrainian students did not face explicit rejection from classmates; rather, we saw a tendency of the Ukrainian students to be neglected. Our findings stand in contrast to reports from school headmasters who asserted that the social integration of Ukrainian students was seamless. We further found a higher proportion of Ukrainian students in classrooms to be related to stronger homophilic behaviour and a lower tendency of Ukrainian students to make friends. Our results therefore imply that increased classroom diversity may negatively influence the integration of refugees in social networks.
Dependence of quantum dot solar cell parameters on the number of quantum dot layers
Authors: Gatissa Tewodros Adaro , Debela Teshome Senbeta , Ali Belayneh Mesfin
Published: July 2023

We report the theoretical results of improved solar cell efficiency form InAs quantum dots (QDs) embedded in the intrinsic region of n-i-p GaAs structure. The effect of QD layers on the QD solar cell parameters is explained in detail. For QD layers of 250, we obtained a maximum efficiency of 27.4%. Increasing the number of layers beyond the optimum value resulted in the decrease of efficiency. The presence of InAs QD layers in the cell structure results in a significant rise of the short circuit current density from 33.4 mA/cm2 without InAs QD to 45.4 mA/cm2 in the presence of InAs QD. At the same time, the efficiency of the cell increased from 20.5% without InAs QD to 27.4% with InAs QD.
Bandgap narrowing in zincblende III–V semiconductors: Finite-temperature full random-phase approximation and general analytical model
Authors: Schenk A.
Published: July 2023

The bandgap narrowing (BGN) in zincblende III–V semiconductors is calculated in a finite-temperature full Random-Phase Approximation (RPA) formalism based on an isotropic dispersion model. The cases of n-type and p-type quasi-neutral regions and the case of a neutral electron–hole plasma are elaborated for the technologically important materials GaAs, AlAs, InAs, GaP, InP, GaSb, InSb, zb-GaN, zb-InN, Al0.3Ga0.7As GaAs0.5Sb0.5, InP0.69Sb0.31, InAs0.4P0.6, InAs0.4Sb0.6, In0.52Al0.48As In0.49Ga0.51P, In0.53Ga0.47As In0.5Ga0.5Sb, and zb-Ga0.5In0.5N (60 cases). In quasi-neutral regions, the correlation energy of the interaction between carriers and ionized dopants adds two terms to the total BGN. At low temperatures, inefficient screening makes the hole term dominant in n-type materials with a large ratio of the valence band to the conduction band (CB) density-of-states. The inclusion of the CB nonparabolicity is decisive here, as it prevents a diverging BGN at high concentrations. For all 60 cases, the BGN is evaluated in the temperature range from 0 to 500 K. A strong temperature dependence over the whole density range is observed in all direct n-type materials. Otherwise, the temperature dependence quickly ceases with increasing density. An analytical model of BGN without material-dependent free fit parameters is derived and compared with the full-RPA results.
The multifield regulation on resistance of PbPd0.9Co0.1O2/PMN-PT(001) laminate film
Authors: Wang Ke , Chen Shuiyuan , Huo Guanzhong , Li Jinyan , Ye Qingying , Su Chao , Huang Zhigao
Published: July 2023

Spin gapless semiconductor (SGS) presents abundant electric and magnetic properties and is highly sensitive to external factors, such as current, electric field, magnetic field, and stress. This paper reports on a PbPd0.9Co0.1O2/PMNPT(001) laminate thin film with the “SGS/ferroelectrics” structure, which exhibits significant current-induced resistance (I-ER) effect. More importantly, the colossal static electric-field-induced resistance (E-ER) effect in such a laminate film was observed for the first time. The introduction of lattice defects (Pb vacancies) induces a local electric field, electron spin ordering state, and ferroelectric polarization field effect to explain the excellent physical properties. The reported laminate thin film composite exhibits promising application potential in spintronic devices, composite sensor units, storage systems, and other low-energy semiconductor electronic device fields. This work proposes an alternative way to investigate the novel properties for spin gapless semiconductors and expand the research fields of multi-field modulation effect in magnetoelectric composites.
Modulational instability and nonlinear dynamics of femtosecond lasers in transparent materials with non-Kerr nonlinearities
Authors: Ngek I. Ndifon , Dikandé Alain M.
Published: July 2023

Femtosecond laser inscription in transparent materials is a physical process that finds widespread applications in material engineering, particularly in laser micromachining technology. In this process, the nonlinear optical response of the transparent material can be either intrinsic or induced by multiphoton ionization processes. In this work, a generic model is considered to describe the dynamics of femtosecond laser filamentation in transparent materials characterized by non-Kerr nonlinearities, focusing on the influence of multiphoton ionization processes in the generation of an electron plasma of inhomogeneous density. The mathematical model consists of a complex Ginzburg–Landau equation with a generalized saturable nonlinearity, besides the residual nonlinearity related to multiphoton ionization processes. This generalized complex Ginzburg–Landau equation is coupled to a rate equation for time evolution of the electron plasma density, where multiphoton ionizations are assumed to be the sole processes controlling the generation of the electron plasma. Dynamical properties of the model are discussed starting from the continuous-wave regime, where a modulational-instability analysis enables us to determine the stability conditions of continuous-wave modes in the system. The analysis reveals a dominant tendency of continuous-wave stability for relatively large values of the multiphoton ionization order K, provided the femtosecond laser operates in the anomalous dispersion regime. Numerical simulations of the mathematical model feature a family of wavetrains composed of self-focused, well-separated, pulse-shaped optical filaments whose repetition rates are shortened but amplitudes are increased, with an increase in K. Simulations suggest that such nonlinear wavetrain structures do not need the transparent material to be intrinsically nonlinear and that they may also be favored solely by the nonlinearity induced by multiphoton ionization processes in a linear transparent material.
Quantum description of free electron laser radiation and nonlinear amplitude equations
Authors: Tzenov Stephan I. , Chen Zhichu
Published: July 2023

A relativistic quantum mechanical model to describe the quantum free electron laser dynamics has been developed. Neglecting the spin of electrons in the impacting beam, this model is based on the Klein–Gordon equation coupled to the Poisson equation for the space-charge potential and the wave equation for the transverse components of the radiation field. Furthermore, a system of coupled nonlinear envelope equations for the slowly varying amplitudes of the electron beam distribution and the radiation field has been derived. The fundamental system of basic equations has been cast into a suitable hydrodynamic formulation. In the framework of the hydrodynamic representation, a new dispersion relation has been derived and analyzed in both the quantum and the quasi-classical regimes, where the space-charge oscillations of the electron beam are taken into account.
Machine learning opens a doorway for microrheology with optical tweezers in living systems
Authors: Smith Matthew G. , Radford Jack , Febrianto Eky , Ramírez Jorge , O’Mahony Helen , Matheson Andrew B. , Gibson Graham M. , Faccio Daniele , Tassieri Manlio
Published: July 2023

It has been argued that linear microrheology with optical tweezers (MOT) of living systems “is not an option” because of the wide gap between the observation time required to collect statistically valid data and the mutational times of the organisms under study. Here, we have explored modern machine learning (ML) methods to reduce the duration of MOT measurements from tens of minutes down to one second by focusing on the analysis of computer simulated experiments. For the first time in the literature, we explicate the relationship between the required duration of MOT measurements (Tm) and the fluid relative viscosity (ηr) to achieve an uncertainty as low as 1% by means of conventional analytical methods, i.e., Tm≅17ηr3 minutes, thus revealing why conventional MOT measurements commonly underestimate the materials’ viscoelastic properties, especially in the case of high viscous fluids or soft-solids. Finally, by means of real experimental data, we have developed and corroborated an ML algorithm to determine the viscosity of Newtonian fluids from trajectories of only one second in duration, yet capable of returning viscosity values carrying an error as low as ∼0.3% at best, hence opening a doorway for MOT in living systems.
Design, analysis, circuit implementation, and synchronization of a new chaotic system with application to information encryption
Authors: Yang Yuwei , Gao Jie , Imani Hashem
Published: July 2023

The practical applications of chaotic systems are gaining more dimensions every day. In this paper, a new 3D chaotic system is presented with three nonlinear terms and unique strong chaotic behavior. For the initial evaluation of the behavior of the innovative chaotic system, analyses related to equilibrium points, sensitivity, stability, Lyapunov exponent, and bifurcation have been carried out, and its strong attractor manner has been well shown. The practical realization of the designed system is shown by its circuit implementation through the use of electronic elements and Kirchhoff’s laws. To show the performance of the innovative system in practical applications, first a synchronization technique inspired by non-linear and active approaches has been designed, and then by using the innovative chaotic system in the masking technique, a new information encryption method has been derived. The results obtained from the masking based on the innovative chaotic system and the designed synchronization technique show the high functionality of the derivative encryption method.
Evaluation of between-assay consistency among laboratory testing methods for neurosyphilis: a systematic review
Authors: Zhang Xu , Du Fang-Zhi , Wang Qian-Qiu , Zhang Rui-Li
Published: July 2023

We conducted a systematic review to analyse the consistency of nontreponemal-specific tests of Treponema pallidum in cerebrospinal fluid. We searched the PubMed, EMBASE, Web of Science, CNKI, Wanfang and Chongqing VIP databases. The inclusion criteria were studies conducted on nontreponemal-specific tests in cerebrospinal fluid (CSF) within the same population. Exclusion criteria were studies with incomplete data or where we were unable to obtain the full text, duplicate reports, case reports and studies without sensitivity or specificity results. We used kappa value analysis and McNemar’s test to analyse study consistency. We initially collected a total of 198 articles and ultimately included six articles that involved 429 patients with neurosyphilis. The performance between venereal disease research laboratory tests (VDRL) and the reactive plasma regain or toluidine red serum unheated test was similar. The kappa value for consistency between VDRL and reactive plasma regain was >0.8 in three articles, and was 0.892 for consistency between VDRL and toluidine red serum unheated test in one article. Our results suggested that CSF-reactive plasma regain or CSF-toluidine red serum unheated test may serve as alternative tests in the diagnosis of neurosyphilis with CSF-VDRL.
Time, scope and resources: why U=U makes programmatic sense for Nigeria
Authors: Magbadelo Dorcas T. , Phillips Abimbola , Christopher-Izere Pius , Oyeledun Bolanle
Published: July 2023

Nigeria’s widespread mixed epidemiology HIV program has achieved a 26% reduction in new infections since 2010. New HIV infections in Nigeria remain higher in key populations, adolescent girls and young women. Treatment as prevention was a relatively new concept in Nigeria in 2016, with U=U adopted and launched in 2019 by the Federal Ministry of Health. This paper provides justification on why a sustained focus on U=U campaigns in Nigeria will contribute to the successes of the Nigerian HIV program, improving the possibility of HIV epidemic control and attaining equitable health outcomes for all sub populations in Nigeria.
From crushes to squishes
Authors: Fine Julia Coombs
Published: July 2023

Previous research on language, sexuality, and affect has focused primarily on the presence rather than the absence of desire. This analysis investigates the linguistic manifestations of non-desire on two subreddits:r/AskRedditandr/Asexual. Contrasting asexual redditors’ responses to threads such asWhen and how did you realize you were asexual?with straight, allosexual redditors’ responses to a thread titledStraight redditors, when did you realize you were straight?, I find that allosexual and asexual redditors’ responses differ in agency and emotionality. While straight allosexual redditors attribute their lack of homosexual desire to factors other than themselves, asexual redditors attribute their lack of allosexual desire to their own identity. Additionally, asexual redditors frame their realizations of their asexuality as processual and emotional, usingfeelandfeltmore often than straight allosexual redditors’ responses. These results expose the importance of emotionality – including lack of desire – as a resource for asexual identity construction.
Research on Thermal Insulation Characteristics of Thermal Barrier Coating Materials Based on Human-Machine-Environment Engineering
Authors: Wang Cuicui , Hou Qingqing , Wei Zhenbiao
Published: July 2023

Aiming at the problem that automotive human-machine-environment engineering research the temperature in the vehicle is too high to restrict the working efficiency of personnel and the comprehensive performance of the vehicle. This paper expounds the essence of human-machine-environment engineering research, analyzes the current research status of thermal barrier coating materials, compares and analyzes the thermal insulation performance of thermal barrier coating materials at various stages, and verifies the thermal insulation characteristics of thermal barrier coating materials through experiments, which provides a theoretical reference for the research of human-machine-environment engineering in the automotive field.
Study on the effect of high temperature heat treatment of H2 on the pore structure of activated carbon
Authors: Tao Hongbo , Song Shuai
Published: July 2023

As a high-quality adsorbent, activated carbon is widely used in air purification, natural gas storage, sewage treatment, gas enrichment, and separation, etc. The pore microstructure of activated carbon directly affects the adsorption capacity. In this paper, the altered in the microstructure of activated charcoal before and after high-temperature treatment were investigated by high-temperature thermal treatment of activated charcoal at 600°C and 700°C under an H2 atmosphere. The results of low-temperature (77 K) nitrogen adsorption showed that after high-temperature H2 heat treatment, the pores of activated carbon would be ablated and the pore structure would be significantly changed. The specific surface area, micropore specific surface area, total pore volume, and micropore pore volume all increased, and the degree of enhancement was proportional to the temperature of the heat treatment. The pore size distribution of activated charcoal before and after heat treatment was analyzed by density functional theory, and it was concluded that the pore volume of activated carbon mesopores (2-4 nm) increased significantly after high-temperature heat treatment, which could effectively improve the adsorption and separation capacity of activated carbon in larger molecular systems.
Study on Adsorption Behavior of Sustained-release Polycarboxylate ether Molecules using Molecular Dynamics Simulation
Authors: Lin Xiaochen
Published: July 2023

At present, many experimental studies have focused on the mechanism of performance of sustained-release polycarboxylate ether (PCE), but research on it from a microscopic perspective is still lacking. In this study, molecular dynamics simulation was used to conduct theoretical calculations on the molecular conformation and adsorption behavior of slow-release polycarboxylate ether molecules on the surface of cement lattices, trying to explore the mechanism of slow-release PCE molecules from a microscopic perspective. There are three groups of research design models, which are PCE molecules with ester groups with different degrees of ester group hydrolysis. The three groups of models are used to simulate the adsorption of C3S on the surface of cement particles at three temperatures of 274, 298, and 318 K, and the various parameters of the analysis model. The interpretation of the simulation results shows that the temperature factor and the hydrolysis degree of the ester group will affect the adsorption behavior of the slow-release PCE molecules in different degrees and different aspects.
Molecule Dynamics Simulation of the Effects of Temperature and Vacancy Defects on the Eutectic Sensitivity of CL-20_TNT
Authors: Chen Qing-ci , Chen Fang
Published: July 2023

For contemporary applications, CL-20’s energy density is the highest of any explosive, but it has a very high susceptibility and very low stability. Eutectic techniques can successfully lower CL-20’s susceptibility. However, the eutectic susceptibility can be significantly impacted by the high temperature and many flaws found in its manufacture. By removing CL-20 molecules in Materials Studio (MS) using a molecular dynamics approach, a CL-20/TNT eutectic model with various vacancy concentrations was created in this study. Equilibrium state simulations of the model were run at various temperatures to determine the corresponding kinetic parameters. The susceptibility of CL-20/TNT eutectic-containing vacancy defects is found to increase with the increase in defect concentration and with the increase in temperature, which guides the study of CL-20’s stability and the reduction of susceptibility methods in engineering preparation. Cohesive energy density and binding energy are used at the molecular level as the evaluation criteria of the susceptibility at the macroscopic level.
Parameters Analysis on Flexural Strength of Sisal Fibre Reinforced Mortar: the Effect of Fiber Length
Authors: Huang Jun , Qiu Shichun , Zhang Qianzheng , Fang Kai
Published: July 2023

Sisal fibre is an environmentally degradable material, with a higher tensile strength, it is often used to improve the mechanical properties of cement-based composites. To investigate the influence of sisal fibre size on the mechanical strength of mortar, first, the sisal fibre fraction was kept constant (0.13 wt.%), several different lengths (0 to 40 mm) of sisal fibre were mixed into the mortar matrix, the flexural test results showed that the optimum sisal fibre length was 30 mm. Second, the regression analysis was conducted to further research the influence of sisal fibre length on the flexural strength at varied curing ages (7, 14, and 28 days), and the related shape and scalar parameters to predict the flexural strength of composites were attained. Finally, with the fitting parameters, the corresponding probability density functions were determined. From the fitting results, it showed that the lnln(1/p) was linearly correlated to the ln(fb), and the sisal fibre length may increase the scatter of the experimental data.
Study on Synthesis and Performance of Methyl Diphenyl Urea Stabilizer
Authors: Xia Ping , Jiang Xiabing , Cheng Xiulian , Ma Li , Chang Shengquan , Wang Fei , Zhao Yuanyu , Qiang Zhiduo , Fu Yu
Published: July 2023

Diphenylamine (DPA), formyl chloride, and sodium hydride (NaH) as raw materials synthesize methyldiphenylurea stabilizer by alkylation reaction. The physical and chemical properties of methyldiphenylurea were characterized by nuclear magnetic resonance hydrogen spectrum (1HNMR), X-ray energy spectrum (EDS), Fourier transforms infrared spectroscopy (FT-IR) and differential thermal analysis (DTA). Thermal Decomposition Experiment of Nitrate Propellant Containing Stabilizer by Thermogravimetric Analysis (TGA), exploring the Effect of Different Stabilizers. The molecular surface electrostatic potential energy of methyl diphenyl urea, triphenylamine ( TPA ), dimethyl diphenyl urea (C2), and glycerol trinitrate were calculated by Materials Studio software. The interaction between the stabilizer and glycerol trinitrate molecule was studied. The results showed that the weight loss rate of methyl diphenyl urea was less than 0.1 % within 30 days, and the chemical stability was good. And its negative electrostatic potential energy is larger than that of C2 and TPA, its intermolecular binding ability with glycerol trinitrate is stronger, and its inhibition of nitrate decomposition stability is the best.
Study on Preparation and Mechanism of Concrete Slump Retaining Agent
Authors: Guan Mengqin
Published: July 2023

Using acrylic acid and polyether polymer as the main raw materials, with hydroxyethyl acrylate monomer free radical copolymerization of polycarboxylic acid slump inhibitor, has the effect of reducing the slump loss of concrete. The slow release rate of concrete slump retaining agent synthesized with different ester ratios was studied, and the effects of different ester ratios, different ester ether ratios, and different ambient temperatures on the dispersion, dispersion retention, and hydrolysis rate of polycarboxylic acid slump retaining agent were systematically studied. The knowledge basis for the development of the slump-retaining agent with different sustained release effects. In engineering applications, the working performance of concrete can be controlled more effectively according to the length of the slow release time.
Synthesis and Properties of a New Clay-resistant Polycarboxylic Acid Water Reducer Research
Authors: Jiang Zhuojun , Xiong Qiumin , Chen Xiaobin , Fang Yunhui
Published: July 2023

Due to the shortage of high-quality natural sand, the development of the polycarboxylic acid water reducer with excellent clay resistance has become a research hotspot in recent years. Using acrylic acid, methyl 4-vinylbenzoate, ethylene glycol monovinyl polyethylene glycol ether with a molecular weight of 3000 (EPEG-3000) as comonomers, under the action of sodium bisulfite formaldehyde-hydrogen peroxide redox initiator system initiating system and chain transfer agent mercaptoethanol, a new clay-resistant polycarboxylic acid water reducer with excellent performance was synthesized, named as KZJ-KN. KZJ-KN has the characteristics of high monomer conversion, small adsorption capacity on clay and excellent anti-sludge performance.
Research of Indoor Methane Mass Fraction and Explosion Hazard Prediction Model Based on EKF
Authors: Sun Jingwen , Li Xiaobin , Li Xinhui , Li Quanjun
Published: July 2023

In order to realize the intelligence of the indoor methane supervision system and to deeply analyze and apply the data collected by sensor devices, this paper predicts the indoor methane mass fraction by extended Kalman filter and realizes the prediction of explosion consequences by TNT equivalent method, so as to establish an indoor methane warning model for data collection and analysis. And taking a room of 3×3×3m3 as an example, the indoor natural gas leakage is simulated by CFD, and the data of methane mass fraction change with time is obtained for model simulation and explosion consequence prediction calculation. It is found that the Kalman filter can predict the dynamic change of methane in the room, and the methane concentration in the room gradually reaches the equilibrium state after 10,000s, and the concentration is stable at 3%. The calculation results can provide direction for the accident investigation and provide reference for the decision of accident disposal.
Finite Element Simulation Analysis of Aluminum Honeycomb Sandwich Plate Penetration of Aircraft Under High-Speed Bird Impact
Authors: Yu Shengjie , Chen Lei , Liu Zherui , Jiang Kaiwen , Zhang Jiaming , Chen Zhe , Zhang Xuguang , Zhao Zheng
Published: July 2023

In the process of flight, the penetration caused by bird strikes will cause a significant decrease in the bearing capacity of the material, or even complete loss, which will lead to the accident of the aircraft. Therefore, it is of great significance to study the mechanical properties of aluminum honeycomb sandwich panels at different angles of high-speed bird impact. In this paper, finite element software is used to numerically analyze the penetration process. In this paper, the impact test of the aluminum honeycomb sandwich panel was carried out at 90°, 75°, 60° and 45° at the speed of 170m/s by using 1.8kg birdshot. Through finite element simulation analysis of the damage process, contact force and energy absorption rate of the aluminum honeycomb sandwich panel, it is found that when the bird projectile penetrates the aluminum honeycomb sandwich plate, the aluminum honeycomb sandwich in the impact center will be seriously deformed, torn and penetrated and failed. The angle of bird impact has a great influence on the peak contact force and the decay rate of contact force, the energy absorption effect increases exponentially with the decrease of the angle.
Study on Waterproof Pulp Molding Products Manufactured by Wet-Parison Spraying Process
Authors: Li Mengyao
Published: July 2023

In order to achieve the waterproof effect, the existing pulp molding products mostly adopt the methods of slurry addition, spraying and lamination. Wet-parison spraying is a new low-energy waterproof pulp molding process. In this paper, waterproof pulp molding products were prepared by wet-parison spraying process, and their water resistance and mechanical properties were tested. Three kinds of waterproof coatings, i.e. nanocellulose coating, vegetable-oil coating and polyurethane coating, were selected to spray the wet-parison surface of pulp molding, and then the pulp molding products were obtained by hot pressing. The results show that the wet-parison spraying method is feasible and affects little pulp molding products. After spraying nanocellulose and polyurethane coatings, the stiffness properties of pulp molding products were improved, and the stiffness properties of pulp molding products sprayed with vegetable-oil coatings were decreased. The water resistance of pulp molding products sprayed with nanocellulose coatings is better than those sprayed with polyurethane coatings and vegetable-oil coatings.
Process research on the preparation of high-purity cobalt chloride by chemical precipitation
Authors: Qiao Pengyi , Tan Chengwen , Yu Xiaodong , Xiong Zishan , Dang Jianwei , Chang Hao
Published: July 2023

As the precursor of high-purity cobalt, the purity of cobalt chloride has an important influence on the properties of the cobalt target prepared subsequently. In recent years, in addition to ion exchange and extraction, chemical precipitation is a promising method for the purification of cobalt chloride. High-purity cobalt chloride was prepared by chemical precipitation with ammonium hydroxide and dimethylglyoxime as precipitants. The purification mechanism of high-purity cobalt chloride and the depletion mechanism of the main element Co were studied. Inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray diffraction (XRD) were used to characterize the ion concentration, precipitate phase, and depletion products of the main element Co in the solution. The results show that the concentration of impurity elements Al, Cu, and Cr in cobalt chloride solution can be reduced to less than 0.5 mg/L and the concentration of Fe can be reduced to less than 2 mg/L after removing impurities with ammonia. When a small amount of hydrogen peroxide is added to the solution, the concentration of impurity Fe can be reduced to less than 0.82ug/L. In an alkaline environment where nickel dimethylglyoxime is generated, the main element Co is mainly depleted in the form of [Co(NH3)5Cl]Cl2.
Study on Dust Explosion of Wheat Starch Inerted by NaHCO3
Authors: Duan Yi , Zhu Shunbing
Published: July 2023

With the aim of researching the inerting effect of NaHCO3 upon the wheat starch dust explosion, the test of explosion pressure was implemented by 20L spherical explosion test system. The results showed that as NaHCO3 mass fraction increased, the maximal explosion pressure and the maximal explosion pressure rise ratio of wheat starch dust decreased gradually. When 70wt% NaHCO3 was added, the maximal explosion pressure and the maximal explosion pressure rise ratio of wheat starch dust lessened by 73.82% as well as 93.88%, separately. The deflagration flame propagation experiment of NaHCO3 inerting wheat starch was implemented inside a device of the improved Hartmann tube. These consequences showed that velocity and length of the deflagration flame propagation of wheat starch decreased gradually as NaHCO3 mass fraction increased. When 15wt% NaHCO3 was added, peak velocity and average velocity of deflagration flame of wheat starch decreased by 95.30% and 89.69%, respectively. When 20wt% NaHCO3 was added, the deflagration of wheat starch could be completely inerted.
A review on octupolar tensors
Authors: Gaeta Giuseppe , Virga Epifanio G
Published: July 2023

In its most restrictive definition, an octupolar tensor is a fully symmetric traceless third-rank tensor in three space dimensions. So great a body of works have been devoted to this specific class of tensors and their physical applications that a review would perhaps be welcome by a number of students. Here, we endeavour to place octupolar tensors into a broader perspective, considering non-vanishing traces and non-fully symmetric tensors as well. A number of general concepts are recalled and applied to either octupolar and higher-rank tensors. As a tool to navigate the diversity of scenarios we envision, we introduce the octupolar potential, a scalar-valued function which can easily be given an instructive geometrical representation. Physical applications are plenty; those to liquid crystal science play a major role here, as they were the original motivation for our interest in the topic of this review.
Closed expressions for one-qubit states of convex roof coherence measures
Authors: Cui Xiao-Dan , Liu C L
Published: July 2023

We study the closed expressions of the convex roof coherence measures for one-qubit states in this paper. We present the analytical expressions for the convex roof coherence measures,

C
f

(
ρ
)

, of one-qubit states with

C
f

(
φ
)
:=
f
(

c
0

2

,

c
1

2

)

(where

|

φ
⟩
=

c
0

|

0
⟩
+

c
1

|

1
⟩

) being convex with respect to the l
1 norm of coherence of ϕ (i.e.

C

l
1

(
φ
)

), such coherence measures including the coherence of formation, the geometric measure of coherence, the coherence concurrence, and the coherence rank. We further present the operational interpretations of these measures. Finally, we present the usefulness of the convex roof coherence measures

C
f

(
φ
)

being non-convex with respect to

C

l
1

(
φ
)

by giving the necessary and sufficient conditions for the transformations

p

φ
1

⊕
(
1
−
p
)

φ
2

→
q

ϕ
1

⊕
(
1
−
q
)

ϕ
2

via incoherent operations, where ϕ

i
, φ

j

(
i
,
j
=
1
,
2
)

are one-qubit pure states and

0
⩽
p
,
q
⩽
1

.
Assessment of the University Campus Metabolism due to Mobility and Outdoor Conditions: Survey and GIS-based Approach
Authors: Chen Austin M. , De León L. , Álvarez V. , Bustamante M. , Rodríguez Z. , Mora D.
Published: July 2023

Higher Education Institutions (HEI) aim to improve the use of resources to impact the university community and its surroundings. Resources usage contributes to the university’s metabolism in the form of ecological footprint, i.e., carbon and water footprint. The assessment of various actions that could improve the university metabolism help achieve campus sustainability, leading to the “Green Campus”. The Campus Dr. VLS of the Technological University of Panama was used as a case study. Therefore, this investigation aims to assess microclimate conditions using Geographic Information Systems (GIS) and a field survey to estimate CO2 emissions. In this preliminary study, the land surface temperature (LST) and the carbon footprint because of internal mobilization only by institutional drives because of high-rank staff members’ mobilization among buildings. Results showed evidence of the pandemic effect due to the absence of students and staff, where significant temperature differences were found in 2019 and 2021 over the campus. Only the internal campus trips produce roughly 0.283 kg CO2eq per trip. This translates into an annual total emission of 9.55 t CO2-eq, corresponding to 0.48 t of CO2eq per driver.
DLSU Initiatives and Challenges: Energy & Climate Change
Authors: Maralit Antonio Carlos M. , Tan Dr. Raymond Girard
Published: July 2023

De La Salle University is committed to reducing its impact on the environment and to promoting positive action that will help reduce its carbon footprint. In its vision-mission, it emphasizes the need to be “attuned to a sustainable earth.” This paper presents the different initiatives and challenges faced by the university, especially while still in a global pandemic. A number of initiatives have been undertaken to promote energy efficiency in campus operations and climate action, particularly regarding reducing greenhouse gas emissions. However, facing the COVID-19 pandemic and preparing campus operations for the gradual resumption of face-to-face classes have presented new challenges moving into the next normal. The need to address health and safety concerns has resulted in increased consumption of electricity. Challenges are experienced particularly in ensuring improved indoor air quality as well as allowing indoor-outdoor air exchange. The setting up of (a) air purifiers and/or additional auxiliary fans in high foot-traffic areas, (b) installation of HEPA filters and UV-C lamps into HVAC systems, (c) extended use of air conditioning units to allow purging of air before and at the end of activities, and (d) the opening of air exchange dampers in the University’s HVAC systems, are all expected to result in increased demand for electricity.
Data-based understanding and optimization of sustainability of university mobility: two case studies
Authors: Scagni Andrea , Maggiolini Micol
Published: July 2023

Recently, Italian universities started to collect data on the mobility choices of their communities, in an effort to move towards more sustainable forms of transport. Two examples will be detailed here. First, to foster a significant shift from car to sustainable transport in commuting, car parking space inside university locations will be allocated using individual “sustainable accessibility” indices favoring people that have real difficulties in adopting more eco-friendly modes of transport. To this end, we harness all available data on public transport services as well as road traffic to assess how fast and comfortable commuting sustainably is compared to traveling by car for any specific individual from home to university. The whole process will be web-based, allowing for fast batch computation of such indices for large numbers of people. Second, since university mobility management includes agreements with suppliers of mobility services (such as sharing), offering incentives for their use, we try to shape such agreements based on a community consultation to determine what are the sharing services subscription arrangements most appealing to interested users, thus maximizing their potential.
Wastewater to Wetlands: Turning the Tide with Azolla Ferns
Authors: Kamaleddine F , Keniar I , Yanni S.F. , Elhusseini R , Mohtar R
Published: July 2023

Water pollution is a major problem exacerbated by untreated wastewater discharged into the environment, leading to eutrophication and algal blooms. This research at the American University of Beirut explores the potential of using Azolla pinnata, an aquatic fern, to rid wastewater from ammonium (NH4-N) and soluble reactive phosphorus (SRP), which are the main contributors to eutrophication. A controlled phytoremediation experiment conducted at the Advancing Research and Enabling Communities (AREC) center in the Bekaa valley showed that A. pinnata can decrease NH4-N and SRP in the primary treated wastewater by 98.2% and 96.4% respectively, within 20 days. The color and odor of treated wastewater reverted to the characteristics of fresh water, making this recycling method highly sustainable due to its relatively low cost. The prospective project would be scaled to the university’s farm level by constructing artificial wetlands at AREC using wastewater generated by the farm facilities. The harvested Azolla can be used as animal feed and/or as a green fertilizer. Successfully reintroducing the precarious wetlands in that arid region would alleviate the stress on aquifers and replenish many endemic species currently on their way to extinction. As a result, the university would be treating its wastewater in a sustainable way while contributing to greening the landscape slowly transfigured by desertification.
Integrating technology to develop renewable energy to explore a sustainable future for Taiwan by the SECRDC in NPUST
Authors: Hsu Uzu-Kuei , Tai Chang-Hsien , Yeh Kuei-Jyum , Long Way
Published: July 2023

To keep the next generation safe from the energy depletion crisis and slow the impact of climate change. The world is accelerating the energy transition with the goal of net zero emissions. National Pingtung University of Science and Technology / NPUST established a Sustainable Circular Economy R&D Center / SCERDC. To develop innovative technologies and combine green energy applications across fields for the waste materials, waste recycling and energy saving and carbon reduction of agriculture, forestry, fishery and animal husbandry. Add more strength to “circular economy” and “sustainable environment”.
The architecture of green space by medicinal plants in the university and its impact on people’s ealth, education and environmental in the Post-Pandemic Time
Authors: Mohebi Zahra , Ebadi Hadi
Published: July 2023

Medicinal plants have played an essential role in human healthcare as essential ingredients in traditional medicines and the combination of novel drugs. The architecture of the green space in the university is mainly aimed at the cultivation of plant species that have an eye-catching application. But the green space including medicinal plants in the university space has both effects on the physical and mental health of people and has a good view. It can also be used for teaching students. Therefore, the architectural style of successful herbal botanical gardens needs to reflect a broad understanding of botany and encourage creative thinking in garden design and interpretation. Medicinal Plants gardens are more than just a “pleasant place to visit” because of their unique combination of resources, and it offers a unique opportunity to use plants for human well-being. As a result, the architectural design of the garden may have an impact on its performance. The purpose of this article is to describe the effect of medicinal plants on people’s health and education, as well as their architectural design in universities.
Transforming the University into an Environmental Space
Authors: Carmo Andréa de Araújo do , Santos Kelly Fernanda de Sousa
Published: July 2023

The Environmental Management Superintendence of the Maranhão State University, which works its Environmental Management System through the Environmental Agenda in Public Administration, education for sustainability is being developed continuously and based on A3P since 2015, in all its six axes. In the axis, Awareness and Training of Servants, the opportunity arises to raise awareness environmental issues not only the academic community, but also society as a whole. Through the development of the Green Room Circuit Project, which has been under development since 2018 at the university, the objective was to describe the actions carried out in the year 2021 and to analyze the environmental perceptions of the public after remotely participating in the Green Room Circuit at the Paulo VI Campus. The Circuit consists of five dynamic and successive stages, where lectures corresponding to the contents that would be worked on in each stage were remotely applied. In 2021, due to the pandemic, the Green Room Circuit returned to activities in May, remotely. Fourteen circuits were carried out during the period from May to December, between the different levels of education, 29% of the elementary level, 64% of the secondary level and 7% of the technical level. The activities developed were thematic lectures on: composting, sustainable actions, fungi, agroecological trails, conservation of snakes, mammals and endangered animals. From the public, 580 visitors participated, being 97% students and 3% teachers. The Green Room Circuit on the Paulo VI Campus, education schools in the state of Maranhão has gained an alternative place to know and experience environmental education in an articulated way beyond the classroom, as well as, in the approximation and interaction between basic and higher education system.