bluuebunny/crossref_metadata_2025 huggingface dataset:
An overview of the trigger system at the CMS experiment
Authors: Das Pallabi
Published: March 2022

The trigger system of the Compact Muon Solenoid (CMS) experiment at CERN has been evolving continuously since the startup of the LHC. While the base of the current configuration will remain in use for the next LHC running period (Run 3 starting in 2022), new features and algorithms are already being developed to take care of higher data loads due to increasing LHC luminosity and pileup but also of new experimental signatures to be investigated, in particular, displaced decay vertices stemming from relatively long-lived particles created in proton-proton collisions. Beyond this period, the trigger system will undergo a major upgrade to prepare for the high-luminosity LHC (HL-LHC) operations, which will deliver a luminosity of 5–7.5 times the design value. It corresponds to 140-200 pileup events, defined as overlapping proton-proton interactions in the same or nearby bunch crossings. During HL-LHC, information from the silicon pixel and strip tracker will be available already for the Level-1 Trigger, detector granularity and pseudorapidity coverages will increase. Trigger rates will rise by a factor of about 7.5 both at Level-1 (to 750 kHz) and at the High Level Trigger (to 7.5 kHz) and the latency—the processing time available for arriving at the Level-1 trigger decision—will increase significantly from 3.8 μs to 12.5 μs, allowing for the use of more sophisticated algorithms at the Level-1 trigger.
Effects of neutrino masses and asymmetries on dark matter halo assembly
Authors: Wong Hiu Wing , Chu Ming-chung
Published: March 2022

Massive cosmological neutrinos suppress the Large-Scale Structure (LSS) in the Universe by smoothing the cosmic over-densities, and hence structure formation is delayed relative to that in the standard Lambda-Cold Dark Matter (ΛCDM) model.
We characterize the merger and mass accretion history of dark matter halos with the halo formation time a
1/2, tree entropy s and halo leaf function ℓ(X) and measure them using neutrino-involved N-body simulations. We show that a non-zero sum of neutrino masses Mν
delays the a
1/2 for halos with virial mass between 1013
M
⊙ and 3 × 1013
M
⊙, whereas a non-zero neutrino asymmetry parameter η
2 has the opposite effect. While the mean tree entropy s̅ does not depend significantly on either Mν
or η
2, the halo leaf function does. Furthermore, the dependencies of ℓ on Mν
and η
2 have significant evolution in redshift z, with the relative contributions of Mν
and η
2 showing a sigmoid-like transition as a function of z around z ≈ 0.6. Together with the matter power spectrum, these halo parameters allow us to break the parameter degeneracy between Mν
and η
2 so that they can both be constrained in principle.
Crust Cooling of Soft X-Ray Transients—the Uncertainties of Shallow Heating
Authors: Lu Xiang-Yang , Lü Guo-Liang , Liu He-Lei , Zhu Chun-Hua , Wang Zhao-Jun
Published: March 2022

Crust cooling of soft X-ray transients has been observed after outbursts, but an additional shallow heating during accretion in outburst is needed to explain the quiescent light curve. However, shallow heating is significantly different between sources and even within one source between different outbursts, and the source of shallow heat is as yet unknown. Using the open source code “dStar” which solves the fully general relativistic heat diffusion equation for the crust, we investigate the effect of magnitude and depth of shallow heating on crust cooling and find that some exceptional sources (Swift J174805.3-244637, MAXI J0556-332 during outburst II and GRO J1750-27) in which shallow heating may be inactive could be explained by a deeper shallow heating mechanism. We compare our results with those from previous works and find that the shallow heating is model dependent. In addition, the effects of mass and radius of a neutron star on shallow heating are studied, and it is shown that the more compact the star, the less shallow heating will be needed to fit the crust cooling light curves.
To dee or not to dee: costs and benefits of altering the triangularity of a steady-state DEMO-like reactor
Authors: Schwartz J.A. , Nelson A.O. , Kolemen E.
Published: March 2022

Shaping a tokamak plasma to have a negative triangularity may allow operation in an edge-localized mode-free L-mode regime and with a larger strike-point radius, ameliorating divertor power-handling requirements. However, the shaping has a potential drawback in the form of a lower no-wall ideal beta limit, found using the MHD codes chease and dcon. Using the new fusion systems code faroes, we construct a steady-state DEMO2 reactor model. This model is essentially zero-dimensional and neglects variations in physical mechanisms like turbulence, confinement, and radiative power limits, which could have a substantial impact on the conclusions deduced herein. Keeping its shape otherwise constant, we alter the triangularity and compute the effects on the levelized cost of energy (LCOE). If the tokamak is limited to a fixed B field, then unless other means to increase performance (such as reduced turbulence, improved current drive efficiency or higher density operation) can be leveraged, a negative-triangularity reactor is strongly disfavored in the model due to lower β
N limits at negative triangularity, which leads to tripling of the LCOE. However, if the reactor is constrained by divertor heat fluxes and not by magnet engineering, then a negative-triangularity reactor with higher B
0 could be favorable: we find a class of solutions at negative triangularity with lower peak heat flux and lower LCOE than those of the equivalent positive triangularity reactors.
Lower bounds for Ramsey numbers as a statistical physics problem
Authors: Wouters Jurriaan , Giotis Aris , Kang Ross , Schuricht Dirk , Fritz Lars
Published: March 2022

Ramsey’s theorem, concerning the guarantee of certain monochromatic patterns in large enough edge-coloured complete graphs, is a fundamental result in combinatorial mathematics. In this work, we highlight the connection between this abstract setting and a statistical physics problem. Specifically, we design a classical Hamiltonian that favours configurations in a way to establish lower bounds on Ramsey numbers. As a proof of principle we then use Monte Carlo methods to obtain such lower bounds, finding rough agreement with known literature values in a few cases we investigated. We discuss numerical limitations of our approach and indicate a path towards the treatment of larger graph sizes.
Low-noise amplification of voltage response for thermopile optical detectors
Authors: Li Chaochen , Zhao Yaru , Deng Yuqiang , Xu Tao
Published: March 2022

A technique is presented to amplify the voltage response of thermopile optical detectors. It is based on the parallel combination of multiple operational amplifiers. The background noise of the voltage response has been deceased, which significantly improves the repeatability of the measurement results. Thus, this technique enables the same detector to measure weaker optical power or irradiance at the same precision level. The corresponding amplifying circuit is designed and fabricated. For the same detector, the experimental results show that the standard deviation of the background noise of the combined n op-amps is about

1
/

n

lower comparing with the conventional single op-amp scheme, which is consistent with the theoretical expectations. Furthermore, the lasers of 10 μW and 1μW were also measured by the specific detector and the amplifier circuit. For a 10 μW response, the measurement repeatability of the 8-combined op-amps is about 1.4%, which is better than the 3.3% of a single op-amp. For 1 μW laser, the measurement result of voltage response of the 8-combined op-amps can be precisely quantified; however, the result of the single op-amp is hardly distinguished. The presented technique based on multiple op-amps is practical and can be potential in many applications. We hope this technique could offer help for expanding the measurement ranges of thermopile optical detectors at weaker optical power and irradiance.
Preparation of Dy3+/Tm3+ Co-doped Phosphate Glasses by Melt Method and its Luminescence Properties
Authors: Zhang Tao , Zhang Danyi , Wang Pei-an , Cui Caixia
Published: March 2022

In this paper, P2O5 matrix materials were used to prepare Dy3+/Tm3+ phosphate glasses with different concentrations by high temperature melt method. The emission spectrum of Dy3+/Tm3+co-doped glass samples were measured under 350nm excitation. High-efficiency green and blue down-conversion emissions were already observed. Based on the intensity of the emission peaks of samples doped with different concentrations of Dy3+/Tm3+, It can be assumed that an energy transfer process is occurring between Dy3+/Tm3+, i.e. the energy transfer process between the two kinds of ions is Dy3+ to Tm3+ and Tm3+to Dy3+, respectively. Finally, the energy transfer between Dy3+/Tm3+ was further illustrated by testing the fluorescence decay lifetime of the samples. It was found that the increased probability of cross relaxation of ions in glasses doped with 0.8mol% Dy3+/0.2mol% Tm3+ caused the fluorescence quenching of Dy3+ ions, and a fluorescence color shift from blue to white was observed in the range of 0.2-0.7mol% Dy3+. CIE coordinates of the 0.2mol% Tm3+/0.7mol% Dy3+ co-doped phosphate glasses sample are (0.33, 0.32), which is extremely approximate to the standards of equivalent energy white light for illumination (0.33,0.33). The results indicate that Dy3+/Tm3+ has a significant contribution in the down-conversion mechanism.
The temperature difference method for screening patients with COVID-19 fever symptoms
Authors: Zeng Zhiwei , Mei Guangdong , Liao Tingdi , huang Yantang
Published: March 2022

Coronavirus disease (COVID-19), caused by the SARS-CoV-2 virus, is a potentially fatal disease of global public health concern. Fever has been reported to be a common clinical symptom in COVID-19 and current CDC recommendations for mitigation of community COVID-19 transmission include temperature screening, so prompting widespread temperature screening across multiple sectors, including hospitals, office buildings and airports. The need for no-contact and rapid measurement of body temperature during the COVID-19 pandemic emergency has led to the widespread use of thermal imaging cameras. However, the body temperature measurement is also disturbed by the environment factors, including ambient temperature, background light etc. When the ambient temperature is low, the temperature of the patient will also be low. It was difficult to screen the fever patients by using the absolute temperature criteria, and it often result in missing detection. In order to solve this problem, this paper proposed a method of screening COVID-19 symptom fever patients by the body temperature difference detection. The temperature difference detection method combined the temperature measurement of the infrared imaging camera and the visible camera face recognition. This method will eliminate environmental interference and equipment errors, to reduce the probability of the fever missed detection.
Evaluation of measurement uncertainty of HMP155A humidity sensor based on correlation analysis of input quantities
Authors: Wei Mingming , Wen Chunhua , Li Changchun
Published: March 2022

In view of the current situation that when the humidity sensor used GUM to evaluate the measurement uncertainty, the correlation between the input quantities was not analyzed. We taked the measurement result of the HMP155A humidity sensor at 55% RH as the research object, and analyzed the correlation of its input quantities. After compatibility judgment and calculation of correlation coefficients, the correlation degree was quantified. The evaluation results show that the extended uncertainty of the forward and reverse stroke are both 1.2%RH. The research results show that the measurement uncertainty deviated when the correlation between input quantities was not analyzed, which can easily lead to errors in the determination of instrument conformity. Using this method can effectively make up for the lack of correlation analysised in GUM’s evaluation of humidity sensors in the past, the evaluation content is closer to reality, and the evaluation results are more true and reliable.
Simulation and Optimization Design of Large Wave Power Generation Device Based on Group Array Module
Authors: Cai Nianqi , Li Detang , Zhang Shushu , Wang Jun , Gao weipeng
Published: March 2022

Based on the research achievements of the Haiyuan 1 oscillating buoy wave power generation device, this paper proposes the innovation about a group array of the buoy to increase the output of power generation and realize large-scale power generation. Firstly, the conversion efficiency of wave energy captured by buoys of arrays 3, 6, and 9 for power generation is theoretically estimated. According to wave theory, the energy conversion efficiency of buoy increases with the increase of array number. Then, the modeling and simulation of the buoy array wave energy generation system are carried out by using AMESim simulation software. Through the simulation and optimization of the parameters of the components in the array buoy storage power generation system, the stability and efficiency of the wave power generation device under different array buoys are studied. The simulation results show that by adjusting the volume of the accumulator, precharge pressure and the displacement of the hydraulic motor, the power generation system can not only realize the continuous power output, but also the power output increases with the increase of the number of accumulators. It is proved that the feasibility and rationality of the designed buoy power generation system in group array module, and the research results can make a reliable technical reference for the construction and implementation of large-scale wave power generation system.
Some Major Studies in Experimental Verifications of Bell Inequality
Authors: Tang Jiangmei , Zeng Qingsheng , Zhang Yandong , Qiu Tian
Published: March 2022

Bell inequality plays a crucial role in the debate between quantum mechanical completeness and local realism. It vigorously promoted researches on these aspects, macroscopic quantum superposition states, especially entangled states, and it has brought the debate from theory to experiment, which generated a new discipline, quantum information theory. Thus, this work briefly summarizes some major situations in the verification process of Bell inequality. At the same time, this work analyses existent some problems in the verification process of Bell inequality, and states own perception for the debate.This work can help people better understand the foundation knowledge of quantum information theory, thus quantum information theory can be applied to more actual situations.
Research and application of hydrodynamics modeling of channel in reservoir area-Case of Feilaixia station to Qingyuan station section
Authors: Wang Taiwei , Liu Li , Zhu Weiwei , Wang Yafei
Published: March 2022

In navigable rivers, channel depth and current are the main influencing factors of channel environmental risk, ship navigation mainly relies on channel maintenance water depth information regularly issued by channel departments as guidance, but the long forecast interval limits the full utilization of channel resources to a certain extent. In this paper, by studying the characteristics of the channel from Feilaixia to Qingyuan reservoir area, established the terrain model mesh for the section of the study area, and the two-dimensional shallow water equations are constructed as the control equations of flow simulation. The Model parameters are calibrated and verified. The typical schemes of the channel in the study area were simulated to obtain the channel water depth and velocity information, and the results were visualized, analyzed and discussed. Using two-dimensional hydrodynamic model to simulate channel conditions and calculate flow conditions can provide data support for ship navigation, which has important practical significance for improving navigation management ability.
Study on the dynamic characteristics of stable formation of single droplet in gas-liquid co-flow device
Authors: Gao Shanshan , Liu Zhaomiao , Li Mengqi , Ren Yanlin , Zheng Nan , Cai Fanming
Published: March 2022

The dynamic characteristics of the stable formation of a single droplet in a gas-liquid co-flow device are studied experimentally. The scaling laws of the dimensionless necking radius R of a droplet with dimensionless remaining time τ for different parameters are analyzed, and the reasons for the transformation between these scaling laws are discussed. The results show that the change in the main pressure has little effect on the scaling law. In the earlier necking, R follows a 1/5 power law with respect to τ. In the later collapse, a 2/3 power law is matched. When the auxiliary pressure changes, the pneumatic shear force has a large impact on the earlier necking, causing the scaling law to change, but only a slight effect on the later collapse. Simultaneously, the droplet size and jet limit length decrease significantly with an increase in auxiliary pressure. The results are of great significance for revealing the mechanism of droplet formation and reducing droplet formation size in gas-liquid co-flow devices and provide a theoretical reference for further study of stable droplet formation.
Mechanical Properties and Mechanism Analysis of Magnetorheological Shear Thickening Colloid
Authors: Fu Yankai , Du Chengbin
Published: March 2022

Magnetorheological shear thickening material is a new type of composite material, which has both magnetorheological properties and shear thickening properties.In this paper, the influence of two important factors to the magnetorheological properties and shear thickening properties have been studied. The factors includ boric acid status and the ratio of polydimethylsiloxane to post-treatment boric acid in the material fabrication process .The article also systematically analyzed the action mechanism of the magnetorheological shear thickening material, mainly explained the internal mechanism of cycle that the material changes from the initial chaotic state to the formation of a three-dimensional micro-magnetic particle chain network, and then returns to the initial state. The study of material preparation parameters provides an experiment basis which can provide parameter for the preparation of materials with specified properties.The clarification of the material mechanism provides an idea for the subsequent quantitative analysis of the action of carbonyl iron particles in the material under the three force systems, and provides a theoretical basis for the subsequent study of the material’s kinetic model.
Amplitude reduction optimization of time delay semi-active control for aircraft landing gear shimmy
Authors: Li Feifan , Zhao Yanying
Published: March 2022

Considering the time delay issue in the process of aircraft landing gear shimmy, the time delay semi-active control is used to achieve the purpose of amplitude reduction optimization. Firstly, in order to eliminate the influence of dimensionality and make the results better describe the objective universal law, after dimensionless treatment of the shimmy equations, the influence of dimensionless lateral bending damping coefficient and lateral bending stiffness coefficient of strut on the shimmy amplitude is analyzed. Then, in order to further reduce the amplitude, the time delay semi-active control term is introduced into the shimmy equations, and a mathematical method for solving the characteristic equation of the time-delay dynamic equation is proposed. Designing optimization criterion limits the amplitude of the first resonance to a small enough range. The time delay semi-active control can achieve good vibration reduction effect in the whole frequency domain and eliminate the second resonance. Finally, it is verified and compared in the frequency domain and time domain, the correctness of the calculation and the superiority of time delay semi-active control are proved.
Effect of strain-induced polarization field on band structure of MoS2 nanoribbon
Authors: Dan Minjiang , Hu Gongwei , Liu Nian , Zhang Yan
Published: March 2022

Single-layered transition metal dichalcogenides (TMDs) materials show intriguing device application potential due to their superior adjustability under various mechanisms. External strain can produce huge polarization fields inside two-dimensional piezoelectric semiconductor materials to modulate the relevant properties. In this paper, the strain-induced polarization field in monolayer zigzag MoS2 nanoribbon is specifically discussed. For comparison, we also study the deformation potential by means of the strain-modified bond lengths and hopping energies. The edge states and band gap indicate a distinct change due to polarization field. This work can put forward feasible perspectives for designing low-dimensional materials-based devices.
The Progress of Magnetoactive Origami Structures
Authors: Song Ruiyu
Published: March 2022

Contemporarily, smart materials are utilized for origami fabrication to achieve self-assembly under external stimulation. This technique provides a method to realize remote control of origami structures that can be applied to a variety of areas, e.g., biomedicine and robotics. Thereinto, magnetoactive origami structures were demonstrated in many studies, including the fields of medicine, soft robotics, biotic structure. Their design and manufacture incorporate structural mechanisms, material and additive manufacturing technology, as well as control strategies. This review summarizes existing magnetoactive origami structures as well as their materials and properties. Besides, potential directions and development suggestions are proposed for researchers in the fields of both origami structure and smart magneto-sensitive smart soft materials.
Thermal impact on ultrafast helicity independent all-optical switching of GdxCo100-x
Authors: Fan Xiaofei , Lin Xiaoyang
Published: March 2022

Ultrafast all-optical switching by single femtosecond laser pulse has recently been considered as one of the most potential technologies for the application on high-speed and energy efficient memory device. Here, to ensure such a sophisticated technology to be applicable to more complex environments, we report the dependence of all-optical switching of the ferrimagnet, GdCo, on the ambient temperature. Through heating the GdCo film up to 380 K, we demonstrate the distinct magnetic behaviours and the critical laser fluences of all-optical switching under different composition of Gd. It is found that the thermal stability for AOS will be significantly improved when there are more rare-earth elements, Gd in GdCo. This work provides a deep insight into the thermal effect on helicity independent all-optical switching and will optimize the application of ultrafast technology on the spintronic devices and magnetic memories.
Impact and quasi-static bending tests for a novel composite structure of ceramic and polymeric matrix composites
Authors: Kong Weiyi , Yang Yang , Zhang Xuan , Bao Jiawei , Wang Yangwei
Published: March 2022

To resolve the dilemma between impact resistance and structural stiffness of fan containment casing of modern civil aeroengines, a novel composite structure (CS) is proposed. It combines the hard and stiff ceramic which layered at the impact side and the lightweight and tough polymeric matrix composites (PMC) on the back side. The new structure was tested under ballistic impact loadings and quasi-static four-point bending. The results indicate that the impact resistance of the new structure is improved, compared with the PMC-only samples. Meanwhile, the bending stiffness of the new structure is also substantially larger at the cost of much lower bending strength.
Research on Detonation Growth Characteristics of the Cast CL-20
Authors: Li Shuang , Fan Wenqi , Shen Chen , Yan Shi , Liu Hailun , Nie Jianxin , Guo Xueyong
Published: March 2022

In order to study the detonation growth characteristics of the cast CL-20, shock initiation experiments were carried out. The ∅50mm samples content of 84wt% CL-20, 5wt% mental fuel and 11wt% HTPB binder were prepared. The one-dimension Lagrangian gauge measuring method was used to obtain the pressure histories of the cast CL-20. The results showed that when the loading pressure decreased, the growth of the leading shock wave speed and the front pressure of the explosive slowed down and the time to form a stable detonation was longer. The binder elastomer network effectively reduced the shock wave sensitivity of the cast CL-20 and the critical initiation pressure is 1.40GPa∼2.17GPa. A two-dimension axisymmetric shock initiation numerical model was established. The adaptive genetic algorithm compiled by MatLab was used to call the nonlinear finite element fluid dynamics software (LS-DYNA) to calculate the reaction rate equation parameters of the ignition growth model of the cast CL-20 combined with the results of shock initiation experiments.
Dynamic Behavior of Clay with different Density under Planar Impact
Authors: Li Jin , Li Yunliang , Wu Zutang , Tan Shushun , Zhou Gang , Zhang Guanjun
Published: March 2022

The dynamic behaviour of clay with different initial density was researched by a single-stage light gas gun. Soil samples with four initial density (1.7, 1.8, 1.9 and 2.0 g/cm3) were investigated in this study, the water content, graininess and raw material of which were the same. Four electromagnetic particle velocity gauges were embedded directly into each sample, which was compressed by clay powder. And the motions of shock wave were detected by these gauges. Typical waveforms of the particle velocity and the Hugoniot data of the experiments were presented. The dynamic stress-strain relation could be determined by the Lagrangian analysis method which was utilized to the four particle velocity waveforms. The results show that, the initial density was possibly the most important factor to affect the dynamic behaviour of soft clay soil under intense dynamic load compared with the water content.
Simulation Research on Die Forging Process Optimization of the FDN Type Anti-vibration Hammer Head in UHV Transmission Lines
Authors: Liu Xuliang , Gao Chao , Zhang Shiyao , Li Dongqing , Gu Jian , Si Jianjun , Liu Shengchun
Published: March 2022

Traditional anti-vibration hammer heads are mainly manufactured by gravity casting technology, which has many internal defects and limited mechanical properties, which cannot meet the technical requirements for higher-strength anti-vibration hammers in the construction of UHV transmission lines. Die forging is an advanced material forming process for producing low defect and high strength anti-vibration hammer. However, the process parameters should be strictly controlled to realize the complete filling of forgings and reduce the damage of forgings and dies.In this paper, the die forging process of the FDN type anti-vibration hammer head was simulated by using Deform-3D software platform, and the optimal forging process parameters were proposed as follows: the diameter of the blank is 65mm, the length of the blank is 184mm, the pressing speed of the upper die is 200mm/s, and the preheating temperature range of the blank is 800?∼1000?. The mechanical properties of the anti-vibration hammer after process optimization met the requirements of the corresponding strength grade products.
LBL assembly of Ag@Ti3C2T
X
and chitosan on PLLA substrate to enhance antibacterial and biocompatibility
Authors: Wang Haibo , Dong Ao , Hu Kun , Sun Weiwei , Wang Jundong , Han Lu , Mo Lixin , Li Luhai , Zhang Wei , Guo Yan , Zhu Li , Cui Fuzhai , Wei Yen
Published: March 2022

Poly L-lactic acid (PLLA) is a non-toxic, biocompatible degradable polymer material with excellent mechanical properties after moulding. However, it faces challenges in the use of biomedical materials because of its intolerance to bacteria. Here, we use an easy-to-operate method to prepare a composite multilayer membrane: PLLA membrane was used as substrates to assemble positively charged chitosan and negatively charged Ag@MXene on the surface using the layer-by-layer (LBL) method. The assembly process was detected by fluorescein isothiocyanate-labelled chitosan and the thickness of the coating multilayer was also detected as 210.0 ± 12.1 nm for P-M membrane and 460.5 ± 26.5 nm for P-Ag@M membrane. The surface self-assembled multilayers exhibited 91.27% and 96.11% growth inhibition ratio against Escherichia coli and Staphylococcus aureus strains under 808 nm near-infrared laser radiation with a synergistic photothermal antibacterial effect. Furthermore, best biocompatibility of P-M and P-Ag@M membranes compare to PLLA membrane motivated us to further explore its application in biomedical materials.
Environmental justice criteria for new land protection can inform efforts to address disparities in access to nearby open space
Authors: Sims Katharine R E , Lee Lucy G , Estrella-Luna Neenah , Lurie Margot R , Thompson Jonathan R
Published: March 2022

Substantial funding is being allocated to new land protection and access to protected open space for marginalized communities is a crucial concern. Using New England as a study area, we show striking disparities in the distribution of protected open space across multiple dimensions of social marginalization. Using a quartile-based approach within states, we find that communities in the lowest income quartile have just 52% as much nearby protected land as those in the most affluent quartile. Similarly, communities with the highest proportions of people of color have just 47% as much protected land as those in the lowest quartile. These disparities persist across both public and private protected land, within urban, exurban and rural communities, for different sized buffers around communities, and across time. To help address these disparities in future conservation plans, we develop a screening tool to identify and map communities with high social marginalization and low nearby protected open space within each state. We then show that areas prioritized according to these environmental justice (EJ) criteria are substantially different from areas prioritized according to conventional conservation criteria. This demonstrates how incorporating EJ criteria in conservation prioritization processes could shift patterns of future land protection. Our work provides methods that can be used broadly across regions to inform conservation efforts.
Lie algebra for rotational subsystems of a driven asymmetric top
Authors: Pozzoli E , Leibscher M , Sigalotti M , Boscain U , Koch C P
Published: March 2022

We present an analytical approach to construct the Lie algebra of finite-dimensional subsystems of the driven asymmetric top rotor. Each rotational level is degenerate due to the isotropy of space, and the degeneracy increases with rotational excitation. For a given rotational excitation, we determine the nested commutators between drift and drive Hamiltonians using a graph representation. We then generate the Lie algebra for subsystems with arbitrary rotational excitation using an inductive argument.
The Gelfand–Tsetlin basis for infinite-dimensional representations of

gln(C)
Authors: Antonenko Pavel V
Published: March 2022

We consider the problem of determination of the Gelfand–Tsetlin basis for unitary principal series representations of the Lie algebra

g

l

n

(

C

)

. The Gelfand–Tsetlin basis for an infinite-dimensional representation can be defined as the basis of common eigenfunctions of corner quantum minors of the corresponding L-operator. The construction is based on the induction with respect to the rank of the algebra: an element of the basis for

g

l

n

(

C

)

is expressed in terms of a Mellin–Barnes type integral of an element of the basis for

g

l

n
−
1

(

C

)

. The integration variables are the parameters (in other words, the quantum numbers) setting the eigenfunction. Explicit results are obtained for ranks 3 and 4, and the orthogonality of constructed sets of basis elements is demonstrated. For

g

l

3

(

C

)

the kernel of the integral is expressed in terms of gamma-functions of the parameters of eigenfunctions, and in the case of

g

l

4

(

C

)

—in terms of a hypergeometric function of the complex field at unity. The formulas presented for an arbitrary rank make it possible to obtain the system of finite-difference equations for the kernel. They include expressions for the quantum minors of

g

l

n

(

C

)

L-operator via the minors of

g

l

n
−
1

(

C

)

L-operator for the principal series representations, as well as formulas for action of some non-corner minors on the eigenfunctions of corner ones. The latter hold for any representation of

g

l

n

(

C

)

(not only principal series) in which the corner minors of the L-operator can be diagonalized.
Design and physical validation of a non-planar interlocking element for tubular structures
Authors: Ermolai V , Sover A , Nagîţ G
Published: March 2022

An interlocking topological structure represents an arrangement of parts designed so that the degrees of freedom of each component are takeover by the surrounding neighbours. For the planar arrangements, there are multiple possibilities to design such assemblies via platonic solids such as tetrahedron, cube, octahedron and osteomorphic geometries. This paper describes the geometrical modelling process of a non-planar interlocking element that can be used to produce tubular structures. The geometric element was defined by two curved surfaces identified with the inner and outer shell of the tubular structure and joined by six curved surfaces, providing through those the interlocking design. The virtual geometry was produced using an additive manufacturing process generating the physical model of a tubular construction assembled from non-planar interlocking elements.
Rapid prototyping method for replacing non-circular gears
Authors: Rizescu D , Besnea D , Rizescu C , Moraru E , Panait I
Published: March 2022

The paper presents a modern method of obtaining non-circular gearwheels from by means of additive technologies. Such a method is useful in case of wear or failure of a mechanical gear which has in its composition such non-circular metal gearwheels in the case of technical systems that must ensure continuous operation. With the help of the FDM technology (Fused Deposition Modeling) it will be created a model of the non-circular gearwheel that will constitute casting model for future gear, or they can even be used as functional gears if a suitable material and a precise execution technology with optimal printing conditions are considered.
Effect of the infill patterns on the mechanical properties of the carbon fiber 3D printed parts
Authors: Pop M A , Zaharia S M , Chicos L A , Lancea C , Stamate V M , Buican G R , Pascariu I S
Published: March 2022

The future in the aeronautical industry is in our conception to obtain 3D printed parts from composite materials of the polymer type reinforced with various materials (fibreglass, carbon, Kevlar, etc.), with very good mechanical properties. In this paper authors analyse the mechanical properties of 3D printed parts obtained by material extrusion of Polyamide based filament reinforced with 15% chopped carbon fibres by three types of infill pattern: grid, triangular and lines and with an infill density of 50%. After testing the specimens, the grid infill pattern showed the lowest average value in the two types of mechanical tests, but the values are higher than those reported in the literature by other researchers. Another fact, it can be concluded that the core configuration does not have a significant influence on the mechanical property’s performance. After microstructures analysis with an optical microscope was observed the defects specific to 3D printing (pores, gaps and agglomerations) were and we determined that the share of defects decreases from grid pattern to lines pattern and for the triangular pattern they are minor even insignificant.
On the laser beam absorption efficiency in laser welding of aluminium thin sheet with copper pipe
Authors: Karmiris-Obratański P , Papazoglou E L , Karkalos N E , Hontzopoulos E , Markopoulos A P
Published: March 2022

Welding is considered the most versatile joining method, with extensive applicability in every modern industrial field. Especially, laser welding technology is widely utilized due to its numerous advantages, and its capability to process a variety of different materials. Among the several process parameters that impact the welding results, the absorbed energy and the power density are of major importance. These parameters mainly depend on the utilized materials and their physical properties, as well as the laser beam inherent characteristics. Moreover, the welding of more complex shapes and geometries is even more challenging, since multiple scatterings are taking place as well. The current paper presents a simulation model of the laser beam path and its absorption in the case of welding an aluminium thin plate and a copper pipe. The Ray Tracing method has been employed, while, the model’s geometrical parameters, are dimensionless, reduced to the pipe's radius. The materials’ absorption coefficient is calculated as a function of the incident angle, while the multiple scatterings are taken into consideration. From the simulation, the total absorption, as well as the relevant power density are calculated for a series of different initial process control parameters, i.e., spot size, incident angle, relevant laser spot position.
Using the finite element analysis to study the cutting speed influence on temperature and internal stresses in the turning process
Authors: Țîţu Aurel Mihail , Pop Alina Bianca
Published: March 2022

The tendency to use the approach ing of finite element method in the turning simulation is becoming increasingly pronounced. The cutting process study based on this type of method requires the identification and knowledge of the geometric tool parameters that define the whole process. This simulation method aims to establish and describe the entire development process, characterized by trying to identify and present the optimal solution or close to an optimal realization and practical development of the entire cutting process. This study aims to draw up tabular analysis reports based on performing a series of simulations on the C45 material using the finite element approaching on DEFORM 2D. During the performed simulations, the same input values of the cutting conditions will be kept, except in the case of the cutting speed, whose modification is the object of the study. In this context, the cutting speed change influences the effective stresses distribution, the temperatures, and the cutting force variation in the cutting process. These issues were followed, and a package of own conclusions and points of view could be operationalized immediately.
Absorbing materials based on magnetically controlled Fe-Al microparticles
Authors: Sosnin M D , Shorstkii I A
Published: March 2022

Rotating permanent magnetic field (RPMF) method was used to obtain an absorbing material based on hexagonally packaged Fe-Al particles. A new kind of material - absorber in the microwave range was obtained. As the main characteristic, the reflection, absorption and attenuation spectra of the electromagnetic radiation of Fe-Al composites were obtained and analysed. Reflection characteristics of Fe-Al composite materials using the RPMF method were improved.
Cementite, still an advanced material: a brief overview
Authors: Bauer Grosse E
Published: March 2022

This paper proposes to give recent advances regarding cementite, a long-known iron carbide. Illustrations for which it remains an advanced material are given in various fields such as metallurgy, catalysis, energy, environment and medicine.
Software strategy for internal combustion engine and electric motor control on a hybrid electric vehicle equipped with belt starter generator and automated manual transmission
Authors: Saragea Ştefan , Toma Marius , Micu Dan Alexandru , Frăţilă Gheorghe , Badea Gabriel
Published: March 2022

In order to fulfil the latest EU emission standards, the average amount of CO2 emissions for each vehicle sold has to be reduced to avoid fines for manufacturers. One of the simplest and cheapest ways of hybridization is the belt starter generator (BSG), which makes it suitable for an entry-level range of vehicles. This paper presents a software strategy developed for internal combustion engine (ICE) and belt starter generator (BSG) control on a vehicle equipped with automated manual transmission and also the drivability, comfort and emission performances improvements expected by using this strategy.
Theoretical and experimental research of an automotive gasoline engine fuelled with butanol
Authors: Sandu C , Pana C , Negurescu N , Cernat A , Fuiorescu D , Georgescu R , Nuţu C
Published: March 2022

Among alcohols used for spark ignition engine fuelling, butanol can be a viable alternative fuel due to its very good combustion proprieties. Butanol has a high miscibility with the gasoline and stable blends can be assured. The higher oxygen content and the higher combustion speed of butanol comparative with gasoline are proprieties which may improve the combustion process and may lead to the reduction of greenhouse gases level such as CO2 and pollutants like CO, HC, and NOx. A theoretical and experimental study was conducted on a spark-ignition engine with 1.5L displacement fuelled with n-butanol-gasoline blends at different volume percentages and different excess air coefficients at the 55% engine load of and 2500 min-1 engine speed. Starting from a predefined model in AMESim was developed and calibrated a physical-mathematical model for the process’s simulation from the engine cylinder. The objective of the paper is to get a good representation of the real engine in numeric to have a better prediction of the engine performance at the different operating conditions. The theoretical and experimental investigations show important advantages of n-butanol in blend with gasoline: the increase of the thermal efficiency due to the stable engine operation at lean mixtures use.
CAM optimization in moulds retrofitting
Authors: But Adrian , Gal Lucian
Published: March 2022

Because the moulds are using in mass production, in time, defects appear, and their wear leads a big number of rejects parts. The cost to manufacturing a new mould is high, so, it is often used to retrofitting used moulds. The paper presents the moulds manufacturing steps correction, with applications and a computer aided manufacturing solution on CNC machine tools. Locating the defective area, choosing the most efficient milling strategies, protecting the parts area without defects in the mould during processing, paying attention to possible collisions during work or in positioning the cutting tools, the CNC programmer is fully engaged and have a big responsibility. The paper come with innovative CAM solutions to optimize the mould manufacturing process.
Field robots development in the aspect of achieving the goals of sustainable agriculture
Authors: Sobocki S , Wojciechowski J , Legutko S , Mac J , Zawada M , Szymczyk S
Published: March 2022

The article deals with the issues related to the use of field robots in agricultural production in the aspect of the use of a sustainable farming system. At the beginning, the very essence of sustainable agriculture is presented and the problems that remain to be solved are identified, thus determining the market demand for autonomous field robots. The next part of the article presents the main division of agricultural robots and an overview of the most interesting solutions from the last few years that have been implemented by private companies and research centres from around the world. The review of available solutions makes it possible to identify the main challenges related to the implementation of robotic projects into working in difficult field conditions that are faced by the engineers who design them. The projects of autonomous robots used for work in agriculture, implemented by the Łukasiewicz Research Network - Industrial Institute of Agricultural Engineering in cooperation with consortium members, are also presented. At the end of the article, there is a summary and conclusions, which in a general sense define the need for further research on field robots, so as to achieve their fully autonomous work in the near future.
Experimental results regarding the strains and stresses appeared around some lifting ears from a cylinder used in the petrochemical industry
Authors: Iamandei A , Ripeanu R G , Stanciu L , Popa I , Vasilescu S
Published: March 2022

During transporting or raising processes any equipment used in petrochemical industry needs some special ears to be easy and safety manipulated. In the paper are presented some experimental results measured around some lifting ears welded on a cylinder. A special experimental device has been manufactured to complete the experiments. The acquisition data have been registered with a modern Quantum system equipped with a Catman Easy software.
Optimization of risk assessment in renewable energy of Russia by applying statistical calculations of climatic characteristics and GIS technologies
Authors: Nefedova L V , Rafikova Yu Yu
Published: March 2022

Based on the characteristics of the renewable energy sources (RES), current states and also Russia uses the analysis of emerging risks and their management methods for avoiding this problem. The analysis of methodological approaches to assessing emerging risks in the implementation of electricity generation projects based on various types of renewable energy sources is carried out. The problems of assessing the natural resource risks of using renewable energy in the Russian Federation in relation to the climatic regionalization of the territory are examined. The most representative parameters of the ecological and geographical component for assessing the degree of risk by using renewable energy are highlighted. The authors propose a methodology for assessing the degree of risk for using solar resources based on the characteristics calculated of the influx variability for solar radiation to the earth's surface, by assessing and mapping the level of natural resource risks. The levels of resource risks in solar energy development for some regions of Russia were estimated. The paper presents maps of areas with different risk levels in Russia.
Experimental study of the removable assemblies with screws from high pressure injection pumps
Authors: Bistriceanu D P , Bujoreanu C , Pal S G
Published: March 2022

High pressure injection pumps use removable assemblies with screws. They allow the subsequent assembly and disassembly, without destroying the components and the entire assembly, whenever is necessary. Our paper is an experimental analysis highlighting the influence of tightening parameters on components deformations. We perform the study using controller, Janome screwdriver, ZEISS measurement system and SEM (Scanning Electron Microscope) used in the metallographic analysis. Various torques applied on the screws give us results that show the interactions and their impact on the pumps components, producing deformation on the screws, gaskets and even front plate. A trial was done to establish the upper limit for the torque of the screws. After applying several tightening’s at different values, we conclude that the optimal upper limit for screws tightening between front plate and housing is 45 Nm. Applying a torque bigger than 50 Nm, the screws are destroyed, shear. This can generate numerous defects on the sealing gasket area and on the front plate in the screws holes area. The circularity of the front plate is impacted by the thickness of the wall and the inner / outer diameters.