bluuebunny/crossref_metadata_2025 huggingface dataset:
Context matters: Secondary science teachers' integration of process‐based, unplugged computational thinking into science curriculum
Authors: Kite Vance , Park Soonhye
Published: June 2023

There is growing recognition in the education community that the problem‐solving practices that comprise computational thinking (CT) are a fundamental component of both life and work in the twenty‐first century. Historically, opportunities to learn CT have been confined to computer science (CS) and elective courses that lack racial, ethnic, and gender diversity. To combat this inequity, a number of scholars have proposed integrating CT practices into core curriculum——especially science, technology, engineering, and math curriculum. Successfully achieving the goal of integrated CT, however, depends on frameworks to guide integration, professional development for teachers, exemplars of successful integrations, and identifications of the barriers teachers encounter. Research pertaining to each of these areas is in its infancy. This study addresses these needs through a collective case study of 10 secondary science teachers' implementations of a novel, process‐based, unplugged approach to CT/science integration and the factors that supported or hindered their CT/science integration efforts. The results of this work reveal that: (1) an unplugged and process‐based approach to CT/science integration shows promise as a vehicle for infusing CT into diverse science classrooms; (2) educators' teaching context exerts a strong influence on their CT‐integration efforts and persistence; and (3) special attention is needed to support teachers in their CT/science integrations including algorithm creation. This study also demonstrates the utility of the Fraillon et al.'s CT framework as a guide for CT/science integration efforts and sheds light on the unique affordances of unplugged strategies for implementing CT‐integrated science curricula.
Meta‐analysis of the quantitative trait loci associated with agronomic traits, fertility restoration, disease resistance, and seed quality traits in pigeonpea (Cajanus cajan L.)
Authors: Halladakeri Priyanka , Gudi Santosh , Akhtar Sabina , Singh Gurjeet , Saini Dinesh Kumar , Hilli Harshavardan J. , Sakure Amar , Macwana Sneha , Mir Reyazul Rouf
Published: June 2023

A meta‐analysis of quantitative trait loci (QTLs), associated with agronomic traits, fertility restoration, disease resistance, and seed quality traits was conducted for the first time in pigeonpea (Cajanus cajan L.). Data on 498 QTLs was collected from 9 linkage mapping studies (involving 21 biparental populations). Of these 498, 203 QTLs were projected onto “PigeonPea_ConsensusMap_2022,” saturated with 10,522 markers, which resulted in the prediction of 34 meta‐QTLs (MQTLs). The average confidence interval (CI) of these MQTLs (2.54 cM) was 3.37 times lower than the CI of the initial QTLs (8.56 cM). Of the 34 MQTLs, 12 high‐confidence MQTLs with CI (≤5 cM) and a greater number of initial QTLs (≥5) were utilized to extract 2255 gene models, of which 105 were believed to be associated with different traits under study. Furthermore, eight of these MQTLs were observed to overlap with several marker‐trait associations or significant SNPs identified in previous genome‐wide association studies. Furthermore, synteny and ortho‐MQTL analyses among pigeonpea and four related legumes crops, such as chickpea, pea, cowpea, and French bean, led to the identification of 117 orthologous genes from 20 MQTL regions. Markers associated with MQTLs can be employed for MQTL‐assisted breeding as well as to improve the prediction accuracy of genomic selection in pigeonpea. Additionally, MQTLs may be subjected to fine mapping, and some of the promising candidate genes may serve as potential targets for positional cloning and functional analysis to elucidate the molecular mechanisms underlying the target traits.
Effect of ecofriendly grapefruit peel extract on PVC thin films photostabilizing tested under harmful weathering conditions
Authors: Ahmed Hameed , Ahmed Ahmed , Yousif Emad , Ahmed Dina S. , Kadhom Mohammed , Husain Amani , Yusop Rahimi , Bufaroosha Muna
Published: June 2023

Exposure to ultraviolet radiation triggers a photooxidative deterioration mechanism in plastics, resulting in bond breakage, release of volatile substances, overall weight reduction, generation of free radicals, and loose crosslinking. The aim of this study was to obtain a plant extract with appropriate concentration and use it to protect polyvinyl chloride (PVC) from photodegradation. PVC films containing different concentrations of naringin that were already extracted and TINUVIN 622 as a commercial stabilizer were investigated in this paper. UV light was used to irradiate PVC films for 300 h to test the photostability. After radiation, infrared spectra, weight loss, molecular weight reduction, and surface morphology examination for PVC films were studied. In comparison to blank film, the photodegradation of PVC films was significantly reduced by the naringin and TINUVIN 622 photostabilizers. The role of photostabilizers includes deactivating excited states (as quenchers), functioning as effective light filters (pigments and absorbers), scavenging radicals, and decomposing hydroperoxides.
Study on the Influence of Sand Mining in the Channel of Sima Bend in Yangzhong of the Yangtze River
Authors: Hu Cao , Fan Kunpeng , Li Minghua , Wu Jie , Xu Yiwen
Published: June 2023

Taking the sand mining project in a local river section in the lower reaches of Yangtze River, as an example, this paper investigates the complex effects of sand mining project on river potential. Based on MIKE21 software to establish a two-dimensional water–sand mathematical model of the project river section, this study investigates the change of river potential in the local river section near the project after the implementation of different sand mining schemes through numerical simulation to explore the influence of this sand mining project on river potential. The results show that (1) except for slight changes in the project area, there are no significant changes in the rest of the section. Under each calculation condition, the mainstream line in the sand mining area is slightly rightward by about 5 m; (2) the implementation of sand mining project, the diversion ratio of the left branch of Taiping Island slightly increases, and the corresponding diversion ratio of the right branch of Taiping Island decreases, but the change of the diversion ratio is very small, such as the increase of the diversion ratio of the left branch of Taiping Island and the left branch of the inaugurated Island is generally within 0.01% (3) the implementation of the sand project, the water level The overall performance is slightly congested. The implementation of the project has a small impact on the change of the deep flood line in the project section, and the river pattern will not change significantly.
Surface Vibration of Throw-Type Blast in an Open-Pit Mine
Authors: Wang Yong , Xu Chen , Li Changchun , Yao Xiaofei , Xiang Xingbo , Huang Haoxuan
Published: June 2023

In the process of Open-pit mining in China, throwing blasting is an important method, which is very likely to cause serious damage to the slope of the discharge field under the action of vibration load of throwing blasting. With the background of throwing blasting process in Heidaigou open-pit mine in Ordos, vibration velocity data were collected from the discharge field near the throwing blast, and the vibration signal of throwing blast was analyzed by means of Fourier transform to obtain the characteristics of throwing blast vibration velocity wave and the attenuation law and prediction formula in the process of propagation. The results show that: 100 ~ 300 m away from the blasting area, the radial direction (X direction) of the blasting area produces the largest vibration velocity of 26.8 cm/s, but at the same time, the decay rate of the peak vibration velocity of the survey line 2 in each direction is small, and the decay percentages of 56, 75 and 70% are smaller than that of the survey line 1 and survey line 3 in the lateral direction of the blasting area, and the decay rate of the velocity is smaller as the propagation As the distance increases, the decay rate of the velocity decreases. The curve gradually tends to flatten and the vibration velocity of the three directions gradually close. The frequency band of the blast vibration is distributed within 200 Hz and the frequency and energy are mainly distributed in the low frequency stage (0–20 Hz), accounting for more than 50% of the total energy.
Optimization Design of Sand and Loess High Slope Based on Combination of Wide and Narrow Platfom——A Case Study of a High Slope in Yulin City
Authors: Lu Xingya , Li Peng , Su Shengrui , Jiang Haibo , Dong Fu
Published: June 2023

Due to the limited land resources available for engineering construction in Northern Shaanxi, engineering activities such as mineral resources development, basic engineering construction, slope reduction and building houses, and farming are often accompanied by the formation of a large number of Manually Excavated high slopes. Effective high slope design can reduce the waste of land resources, mitigate the damage to the natural environment, and reduce the project cost to a certain extent. Therefore, this paper takes a high sand loess slope in Yulin City, Shaanxi Province as an example, through field investigation, system theoretical analysis and numerical simulation calculation, comprehensively considering the anti scouring property, overall stability and excavation volume of the slope, the design scheme that meets the requirements and consumes the least capital is compared and selected, so as to obtain the optimal slope shape. The conclusion shows that the optimal single slope height of sand loess high slope in Northern Shaanxi is 7–8 m, and the slope ratio is 1:0.75. The setting of wide platform can change the stress distribution of high slope and weaken the continuity of effective plastic strain. The optimal slope shape of the high side slope includes the single slope of 8 m, the slope ratio of 1:0.75, the narrow platform of 3 m wide, 3 wide platforms are arranged, the location of ③④⑤, the width of 10 m, and the excavation volume of 696 m3 (per linear meter).
Key Construction and Control Technology of Long Span Self-anchored Suspension Bridge with Cable Before Beam
Authors: Peng Chengming , Peng Zhihui , Li Jiaqi , Zhang Junzheng
Published: June 2023

Shatian Bridge is a self-anchored suspension bridge with a main span of 320 m. It is constructed by the overall construction technology of “cable before the beam”. The main cable is temporarily fixed through the temporary anchorage system, and the main beam construction is based on the main cable. After the main beam is hoisted and welded, the main cable is temporarily fixed, and the tensile force of the main cable is transferred to the main beam to complete the system conversion. The bridge adopts permanent-temporary combined with temporary anchorage, effectively saving the cost. The lifting of the stiffening beam adopts inverted lifting technology. For the area of the short sling in the middle of the span, a non-full-length joist is designed to solve the problem of main beam lifting in the area of the short sling. During the construction, the steel beam of the anchorage section and the auxiliary pier are temporarily consolidated. The temporary cable actively balances the tension of the main cable with clear stress, which is convenient for construction control. Temperature welds are set at both ends of the closure beam section, which not only makes room for the hoisting of the closure beam section but also avoids the structural safety problems caused by the temperature deformation of the steel beam. The slip control method of cable strands based on water bag weight ensures that the main cable does not slip during steel beam hoisting. The length of the sling is increased through the extension rod, and the horn-shaped guide device is added to avoid sling damage caused by the sling colliding with the conduit mouth. Generally speaking, the construction scheme of “cable before beam” adopted by the bridge is reasonable and feasible, which enriches the construction technology of self-anchored suspension bridges and can provide a reference for similar bridge construction in the future.
Stress State of Asphalt Mortar Based on Meso-Scopic Finite Element Simulation and Verification
Authors: Tan Xiangye , Zhang Yangpeng , Chen Zhipeng , Guo Qinglin
Published: June 2023

The composition and structure of asphalt mixture have a significant impact on its mechanical performance, and the randomly distributed coarse aggregate impose a significant impact on the stress state of asphalt mortar. However, the traditional method can only evaluate the mechanical properties of asphalt mixture from macro scopic indexes, cannot show the stress state of asphalt mortar in details. Therefore, based on digital image processing technology, a meso-finite element model of asphalt mixture is established, and the stress state of asphalt mortar is analyzed by using finite element method. The correlation between the distance from mortar to aggregate and the stress state is established. Results show that the stress of asphalt mortar basically approaches to the external applied stress or zero when the distance from aggregate surface to mortar exceeds 4 mm. The closer it is to the aggregate surface, the greater the stress of the mortar is. Under compressive conditions, asphalt mortar will be affected by tensile stress in its vertical direction, and the maximum tensile stress is about 0.2–0.25 times of the maximum compressive stress. The results of this paper have a good reference for explaining the complex stress state of asphalt mortar.
Research on Key Technology of Rapid Integrated Construction of Fully Prefabricated Rigid Frame Bridge
Authors: Yuan Chao , Li Feng , Wang Min , Tian Fei
Published: June 2023

Based on the reconstruction and expansion project of an expressway, a set of rapid construction technology for integrated erection of fully prefabricated rigid frame bridges is proposed, which solves the problems of unmatched work efficiency of each working face in the conventional integrated bridge erectors and long construction period of traditional suspension assembly technology. This method realizes the rapid construction of this type of bridges in highly urbanized areas. In this method, a new bridge girder integrated erection machine is used to synchronously install precast segmental beams, pier top blocks and precast pier column. At the same time, precast segmental beams near the middle pier are assembled by conventional cantilever assembly method, and the installation method of the precast segmental beams near the transition pier is optimized from the half span suspension assembly method to the cantilever assembly method by temporarily fixing the pier top block and arranging temporary prestressed tendons. This new integrated construction method improves the construction efficiency from 39.5d/unit to 32d/unit, and reduces the interference to traffic and environment.
Study on Ground Deformation Law of Small Spacing Shield Tunneling in Sand and Rock Composite Stratum
Authors: Deng Liwen , Pan Jianting , Ye Haolin , Zeng Jinming , Lu Hao , Pan Hong
Published: June 2023

The construction of shield tunnel often occurs in composite stratum, so it is of great significance to study the law of surface deformation under the working condition of composite stratum in order to ensure the safety of shield construction. Based on the actual tunnel engineering, the law of ground surface soil deformation caused by shield construction in the composite stratum of upper sand and lower rock is studied by using the method of field measurement. The results show that: The width coefficient of the surface settlement trough basically remains stable with the shield construction, and the stratum loss rate changes exponentially with the shield construction; Affected by the disturbance of the previous shield construction, the surface settlement trough caused by the subsequent shield construction is no longer on the top of the tunnel axis, and will move with the construction process, which is greatly affected by the shield attitude parameters; Taking into account the conditions of the center movement of the settlement trough of the subsequent tunnel, the total surface settlement caused by the successive shield constructions adopts the modified Mark-bolt formula to make the fitting parameters of the settlement trough more suitable for reality.
Analysis of Blasting Vibration Signals at Different Initiation Positions of Tunnel Blastholes
Authors: Yan Zhihao , Wang Genzhong , Gao Wenxue , Zhou Min , Hu Wangjing , Ye Jin , Li Yanping , Xie Yuelan , Hu Yu , Zhang Xiaojun
Published: June 2023

In order to study the blasting vibration effect of different blasting points of the tunnel bore, the pilot tunnel in multi-arch tunnel was used to carry out the test of different blasting points of the bore. The results show that: 1) the peak velocity generated by blasting at different initiation points of the hole is different, and the magnitude of the peak velocity is reverse initiation > Intermediate initiation > Forward initiation; 2) The frequency distribution range of blasting vibration signal under the three initiation positions is: forward initiation > Reverse initiation > Intermediate initiation; At the same time, forward initiation is more conducive to the main frequency of blasting vibration signal moving to high frequency; 3) Compared with reverse initiation and intermediate initiation, forward initiation can better disperse energy, so that the energy is transferred from low frequency to high frequency, so that the blasting vibration is relatively small, which is more conducive to the safety of tunnel lining structure.
Experimental Investigation on the Factors Influencing the Shear Strength of Loess-Mudstone Composite Layer
Authors: Zhou Xiaodong , Wang Tienan , Xu Bowen
Published: June 2023

Geological slopes are often disturbed by external engineering, leading changes of the upper moisture content and dry density in loess-mudstone composite layer. It directly affects the shear strength of the loess-mudstone composite layer interface. In order to explore the influence of the upper loess moisture content and dry density on the shear strength of the loess-mudstone composite layer, taking the cutting slope in a test base in Shaanxi Province as the engineering background, different loess moisture contents (10%, 13%, 16%, 19%) and dry densities (1.4, 1.45, 1.5, 1.55 g/cm3) are employed to investigate the shear strength of loess-mudstone composite layers. Scanning electron microscopy (SEM) is used to observe the failure interface of the loess-mudstone composite layer to analyze the failure mechanism of the samples. The results show that: (1) The shear strength of the loess-mudstone composite layer is lower than those of pure loess and mudstone samples. (2) The moisture content of loess will deteriorate the shear strength of the composite layer, and its effect is greater than that of homogeneous loess; but the dry density of loess will enhance the shear strength of the composite layer, and its effect is less than that of homogeneous loess (3) The moisture content and dry density of loess will affect the distribution of pores in the composite layer interface, changing the shear strength of the composite layer. The research can provide certain data and theoretical basis for the prevention and control of landslides at the loess-mudstone interface.
Compaction Effect Due to Single Pile Driving in PHC Pile Treated Soft Clayey Deposit
Authors: Li Guowei , Liu Ruyi , Zhao Chao , Zhou Yang , Xiong Li
Published: June 2023

The compaction effect of extra-long prestressed high-strength concrete (PHC) piles in deep soft soil foundation was studied by field test. The pore water pressure gauge, inclinometer were embedded in different plane positions or different depths of the foundation to monitor the pore pressure and deformation of the foundation when driving pile. The research shows that the magnitude of excess pore water pressure caused by single pile installation is mainly related to buried depth of the measuring point and the linear distance between the pile tip and the measuring point. The shorter the distance or the deeper the depth is, the greater the excess pore pressure caused by pile installation. The horizontal influence radius of pile compacting on the pore water pressure is about 10.7 m. The excess pore pressure induced by pile installation increases with depth, and is obviously affected by stratum properties. In the vicinity of soil with high permeability coefficient, such as thin sand layer or silty fine sand layer, the excess pore pressure cannot be accumulated in a large amount. The existing subgrade obviously restricts the lateral deformation of soil between piles and PHC piles. The pile deformation is small at the top and bottom, and large in the middle. The inflection point of the deformation curve appears at the pile connection position. The relationship the excess pore pressure of the measuring point with the depth and distance of the measuring point is given.
Seismic Data Denoising Analysis Based on Monte Carlo Block Theory
Authors: Jiang Hongliang , Lu Chaobo , Xiong Chunfa , Ran Mengkun
Published: June 2023

Denoising of seismic data has always been an important focus in the field of seismic exploration, which is very important for the processing and interpretation of seismic data. With the increasing complexity of seismic exploration environment and target, seismic data containing strong noise and weak amplitude seismic in-phase axis often contain many weak feature signals. However, weak amplitude phase axis characteristics are highly susceptible to noise and useful signal often submerged by background noise, seriously affected the precision of seismic data interpretation, dictionary based on the theory of the monte carlo study seismic data denoising method, selecting expect more blocks of data, for more accurate MOD dictionary, to gain a higher quality of denoising of seismic data. Monte carlo block theory in this paper, the dictionary learning dictionary, rules, block theory and random block theory is example analysis test, the dictionary learning algorithm based on the results of three methods to deal with, and the numerical results show that the monte carlo theory has better denoising ability, the denoising results have higher SNR, and effectively keep the weak signal characteristics of the data; In terms of computational efficiency, the proposed method requires less time and has higher computational efficiency, thus verifying the feasibility and effectiveness of the proposed method.
Comfort Behavior of High Performance Floor Based on Single-Jump Excitation Mode Considering Time–Space Effect
Authors: Yu Jiang , Xu Haifeng , Zhang Weiyun
Published: June 2023

Because the traditional analysis methods cannot directly describe the comfort behavior of high performance floor through the dimensions of time and space, this paper presents a new method to derive Dirac delta functions and governing differential equations to assess its comfort behavior. On the basis of this, an improved single-jump excitation model is proposed for comfort behavior analysis. In addition, the paper analyzes distribution characteristic of sensitive parameters for the high performance floor. The results show that the peak acceleration is concentrated in the middle of the high performance floor, and then the acceleration response gradually weakened to the two sides, and its degree of weakening is greater along the two corners of the floor model from its spatial and temporal distribution characteristics. In future, it is recommended to change the strength grade of concrete materials to improve its comfort behaviors. The study also demonstrates the strong applicability of improved single-jump excitation model as an effective approach to analyzing the comfort behavior of high performance floor.
Application of Ununiform Arrangement Piling in Reinforcement and Correction of Existing Structures
Authors: Zhou Shengbin , Tong Jianxing , Li Xu , Sun Xunhai , Wang Yahui , Li Jialu , Cao Guoqiang , Li Zhao
Published: June 2023

Due to the construction problem of the original concrete mixing pile, the inclined settlement of a building occurred. After analysis and calculation, the uneven pile distribution in the north and south region is adopted to reduce the subsidence and correct the deviation. According to the comparison between the calculated results and the measured data of the project, the two are basically consistent, which indicates that the method of uneven pile distribution can successfully adjust the distribution of the reaction force of the base and achieve the effect of subsidence reduction and deviation correction.
Model Testing Technique for Piles in Soft Rock Considering the Overlying Layers
Authors: Liu Meiqi , Li Guirong , Wu Kunming , Wang Yuheng , Zhang Xiaosen , Huang Bin
Published: June 2023

Model test is a common method to study the bearing peculiarity of pile foundation. The influence of overlying soil thickness and overburden pressure on the bearing capacity of soft rock-socketed pile should be considered in the physical model test of mini piles in soft rock. In this paper, the influence of coverage on the bearing characteristics of rock-socketed sections is studied by finite element analysis, and the modelling method of equivalent overburden pressure is proposed. This method can be used to study the carrying peculiarity of soft rock-socketed pile and reveal the failure mechanism of pile tip. The development of pile model test technology considering overburden pressure promotes more scientific design methods for pile foundation.
Computer-Vision-Based Structure Shape Monitoring of Bridges Using Natural Texture Feature Tracking
Authors: Zhu Weizhu , Chu Xi , Duan Xin
Published: June 2023

Structural health monitoring is carried out for a limited number of measuring points of the bridge. The root of the problem of bridge damage identification is that the mechanical equation inversion result is not unique due to the incomplete measured data. The full-field description ability of digital images to the structural shapes can effectively alleviate the problem of damage identification caused by incomplete measured data. This project aims to research the full-field shape monitoring method of the bridge. Firstly, the mathematical representation of the corresponding image points on the bridge surface is formed by using the image feature extraction method. Analyze the feature points position change mathematical model before and after deformation, and propose the structural full-field displacement vector calculation theory. Verify the full-field displacement calculation theory by a test beam. The results show that the maximum absolute error of the vector length is 0.24 mm and the relative error is less than 5%. The research realizes the structural full-field displacement monitoring under the natural texture condition for the first time. The results can promote the application and development of digital image processing technology in the field of structural health monitoring, improve the level of bridge safety evaluation, and realize the automation, intelligence and visualization of structural deformation monitoring.
Study on High Temperature Performance of Asphalt Mixture and Correlation of Its Evaluation Indexes
Authors: Lv Dongbin , Zhang Honggang , Zeng Lihao , Lei Jiechao
Published: June 2023

In order to better evaluate the high-temperature performance of asphalt mixture, based on the conventional rutting test and Hamburg rutting test, this paper further studies the influence of temperature, grading and asphalt type on the high-temperature shear resistance of asphalt mixture by using uniaxial penetration test and uniaxial compression test. Based on Mohr Coulomb theory, the cohesive force and internal friction angle of mixture were calculated. Based on the analysis of variance, the significance of the influence of temperature and gradation on the high-temperature shear characteristics was studied. Linear regression analysis was used to reveal the correlation between the fractal dimension treated gradation and the shear resistance characteristics. Finally, the correlation between the high-temperature shear resistance performance index and the high-temperature rutting resistance evaluation index was analyzed. The results show that temperature has a significant effect on cohesion and internal friction angle of gradation pairs, and the fractal dimension Dc of coarse aggregate is positively correlated with cohesion and internal friction angle, with the strongest correlation. It indicates that the high-temperature performance of the mixture can be improved by increasing the passing rate of the sieve hole above 4.75 mm in the grading design. The correlation R2 between cohesive force index and high-temperature rutting resistance index of mixture at 35 ℃ is higher than 0.9, which belongs to extremely strong correlation. The shear resistance index of cohesion at 35 ℃ can be used to characterize the high-temperature rutting resistance of asphalt mixture.
Finite Element Analysis of Self-centering Reinforced Concrete Shear Walls
Authors: Yagoub Nouraldaim F. A. , Wang Xiuxin
Published: June 2023

Post-tensioned precast concrete walls are an attractive research trend in structural engineering, which replaces cast-in-place concrete walls in earthquake-prone buildings. Precast concrete walls use mild steel and high-strength post-tensioning steel for flexural resistance. Mild steel reinforcement yields in tension and compression, dissipating inelastic energy. Unbounded tendons are used inside the wall to give self-centering capability, which lowers residual displacements. At the wall-foundation, horizontal slots are installed equally. Meanwhile, the middle-wall concrete is still anchored to the base. A three-dimensional finite element (FE) model is developed in this study to assess the lateral load response of shear walls with horizontal bottom slots. The seismic performance of three distinct walls is evaluated using the Abaqus software FEA. The model is validated by comparing the experimental data accessible in the literature. Furthermore, we investigate the effects of bottom slit length, steel strand position, initial prestressing level, and concrete strength. All of these criteria are critical for constructing structures with the new concept. The results of this study show that the three-dimensional finite element model accurately predicts all of the above-mentioned properties, including the lateral force–displacement response and toe area damage of self-centering shear walls.
Nonlinear Dynamic Behaviour of Hollow Piles Based on Axial Harmonic Loading
Authors: Sharma Surya Prakash , Choudhary Shiva Shankar , Burman Avijit
Published: June 2023

The main objective of the current work is to examine the dynamic axial response of three pile group under machine-based harmonic loads. Field tests are carried out under axial harmonic excitations on a group pile with a pile length of 300 cm and an diameter of 11.4 cm in order to accomplish this objective. For various eccentric moments, the frequency versus amplitude responses of the group pile are measured. The field test results of the soil-pile system show non-linear behaviour as their resonant frequencies decrease and their resonant amplitudes disproportionally increase with eccentric forces. The inverse methodology proposed by Novak (1971) is used for the theoretical study. With this methodology, the changes in stiffness, damping, and effective mass of the piles under various eccentric moments are quantified by analyzing the frequency-amplitude response curves of field results. The theoretically back-calculated soil-pile system response curves are compared with the field results, and it is observed that the analytically predicted responses closely match the field responses. It is also found that the values of estimated damping of the pile group increased, while effective mass and average stiffness values decreased with an increase in eccentric moments.
Research on Construction Method of Soft Soil Foundation Pit with L-Shaped Small Steps
Authors: Cao Yanhui , Ye Jinhua , Hao Gang
Published: June 2023

A layered, segmented, and block building technique was created during the construction of the cut-and-cover foundation pit. Traditional foundation pit excavation often necessitates both support erection and mechanical excavation at the same time, however owing to the intersection of support and excavation mechanical operation, which may decrease building efficiency, and the construction requirements are higher due to the low mechanical characteristics of the soil in the silty soil layer. Therefore, the construction method of an L-shaped short step with small steps soft soil foundation pit is proposed, based on the mechanical characteristics of the silty soil layer and the construction operation characteristics of the foundation pit. After excavation, the support is erected using a numerical calculation of the stability of the foundation pit. According to engineering practice, the L-shaped short step with small steps soft soil foundation pit building technique can significantly facilitate basement pit deformation, improve construction efficiency, and be popularized.
Study on Structural Performance and Design Method of Rectangular Steel Plate Water Tank
Authors: Tang Gan , Jia Zelong , Li Peng , Ye Ziheng , Dou Junchun
Published: June 2023

According to the engineering requirements of the integrated sewage treatment equipment, the structural design of the steel plate water tank used in the integrated sewage treatment equipment is carried out. Based on the investigation of actual projects and theoretical analysis, proposed the failure mode of steel plate water tank structure and the corresponding design guidelines. The finite element modeling calculation of the steel plate water tank project example is carried out to obtain the calculation results of the stress–strain level and displacement of the water tank structure under the stress state, so as to analyze the structural performance of the steel plate water tank structure and judge whether the water tank structure reaches the failure state accordingly. According to the design guidelines to adjust the structural arrangement and member size to ensure the safety of the water tank structure in the process of use, providing design methods for the design of steel plate water tank structure.
Numerical Evaluation of Punching Shear Capacity Between Bonded and Unbonded Post-tensioned Slab Using Inverted-U Shape Reinforcement
Authors: Khatib Milad , Saleh Zaher Abou
Published: June 2023

The Both bonded and unbonded prestressing tendons may be used to reinforce post-tensioned (PT) concrete members. The binding state of tendons may have an impact on how well different types of PT concrete elements function in flexural and shear loads. Inverted-U shape reinforcement was used experimentally to enhance the behavior of different structural elements. The obtained results confirmed the proposed model’s accuracy for both PT slabs and beams (bonded, and unbonded). This study's major goal is to compare numerically PT concrete slabs provided with inverted-U shape reinforcement with the two different tendon systems and evaluate their performances due to applying punching shear load. To do this, the PT slab that has already been tested is reexamined numerically. By using, a nonlinear finite element, the results were carried out utilizing visualization tools. For a better study of the behavior of bonded and unbonded PT slabs, the obtained numerical results, and the previous experimental one are compared. Good correlations are shown.
Analysis of the Effect of the Deep Excavation of a High-Rise Building on the Deformation of the Ground Surface and Diaphragm Wall
Authors: Nguyen Hong Nam
Published: June 2023

Study on the influence of the deep excavation by top-down construction method on the deformation of the adjacent ground surface and diaphragm wall has been analyzed in detail for a deep foundation pit of a high-rise building at 27 Lang Ha, Hanoi. The analysis was implemented by the finite element method. The influencing factors such as wall stiffness, wall depth, ground surface load, and initial groundwater level were carefully investigated by applying a parametric study, taking two cases of short-term and long-term working conditions. The simulated results show that the settlement of the ground surface adjacent to the deep excavation depends significantly on the surface load and the initial groundwater level. Under the long-term condition, the calculated ground surface settlement has a larger value than that under the short-term condition. The simulated horizontal displacement and the bending moment of the diaphragm wall depends significantly on the initial groundwater level and the large surface load.
Investigation on Contact Force for Asphalt Mixture During Compaction Using DEM
Authors: Feng Jian , Liu Weidong , Lei Jiechao
Published: June 2023

Contact force for asphalt mixture has a significant effect on mechanical properties, and discrete element method (DEM) is a feasible and efficient numerical simulation approach to investigate on skeleton structure of asphalt mixture from microscopic perspective. A three-dimensional (3D) DEM compaction model which can well describe morphology characteristics of mineral aggregate, compaction temperature, was established to investigate the contact force. It indicates that aggregate–aggregate (A-A) merely exists in contact pressure force, aggregate–mortar (A-M) and mortar–mortar (M-M) exists in contact pressure force and tension force. While contact force of two-dimensional (2D) sections is employed to characterize the contact force of 3D specimens, it needs to investigate rationality of the selected section. The 3D DEM compaction model can be utilized to investigate contact force for asphalt mixture.
Research on Carbon Footprint Calculation and Evaluation in Assembled Building Phase
Authors: Zhao Miaomiao , Zhu Jiwei , Han Pengwei , Liu Chengling
Published: June 2023

This study takes the carbon footprint of prefabricated buildings as the research object, and divides its physical and chemical process into four stages: building materials mining (production), prefabricated component production, material transportation and on-site construction. According to the carbon footprint sources of each stage, a carbon footprint model is established, and the carbon footprint factors and consumption factors required in the model are analyzed. Build a three-dimensional model based on BIM technology, and convert the consumption in combination with the project consumption quota to provide a data basis for calculation. The carbon footprint concentration produced in each stage of prefabricated buildings and cast-in-place buildings is analyzed by cases, and corresponding countermeasures and suggestions are put forward.
Classical observables from partial wave amplitudes
Authors: Lee Hojin , Lee Sangmin , Mazumdar Subhajit
Published: June 2023

Abstract

We study the formalism of Kosower-Maybee-O’Connell (KMOC) to extract classical impulse from quantum amplitude in the context of the partial wave expansion of a 2-to-2 elastic scattering. We take two complementary approaches to establish the connection. The first one takes advantage of Clebsch-Gordan relations for the base amplitudes of the partial wave expansion. The second one is a novel adaptation of the traditional saddle point approximation in the semi-classical limit. In the former, an interference between the S-matrix and its conjugate leads to a large degree of cancellation such that the saddle point approximation to handle a rapidly oscillating integral is no longer needed. As an example with a non-orbital angular momentum, we apply our methods to the charge-monopole scattering problem in the probe limit and reproduce both of the two angles characterizing the classical scattering. A spinor basis for the partial wave expansion, a non-relativistic avatar of the spinor-helicity variables, plays a crucial role throughout our computations.
Neutrino mass and leptogenesis in a hybrid seesaw model with a spontaneously broken CP
Authors: Pramanick Rohan , Ray Tirtha Sankar , Shaw Avirup
Published: June 2023

Abstract

We introduce a novel hybrid framework combining type I and type II seesaw models for neutrino mass where a complex vacuum expectation value of a singlet scalar field breaks CP spontaneously. Using pragmatic organizing symmetries we demonstrate that such a model can simultaneously explain the neutrino oscillation data and generate observed baryon asymmetry through leptogenesis. Interestingly, natural choice of parameters leads to a mixed leptogenesis scenario driven by nearly degenerate scalar triplet and right handed singlet neutrino fields for which we present a detailed quantitative analysis.
The Bloch–Nevanlinna Problem Under Lineability
Authors: Bernal González L. , Bonilla A.
Published: June 2023

The original version of the celebrated Bloch–Nevanlinna problem asked whether there exists or not a holomorphic function in the unit disc of bounded characteristic whose derivative is not of bounded characteristic. This problem has been solved in the affirmative by a number of mathematicians. Starting from a result on topological genericity of this class of functions due to Hahn, our work intends—under an algebraic as well as a topological point of view—to contribute to this topic. Specifically, the family of solutions of the Bloch–Nevanlinna problem is proved to be residual in appropriate topological spaces, and it contains, except for the zero function, dense maximal dimensional vector subspaces, large linear algebras and infinite-dimensional Banach spaces.
Locally Homogeneous $$C^0$$-Riemannian Manifolds
Authors: Lebedeva Nina , Nepechiy Artem
Published: June 2023

We show that locally homogeneous $$ C^0$$

C
0

-Riemannian manifolds are smooth.
Children diagnosed with presymptomatic type 1 diabetes through public health screening have milder diabetes at clinical manifestation
Authors: Hummel Sandra , Carl Johanna , Friedl Nadine , Winkler Christiane , Kick Kerstin , Stock Joanna , Reinmüller Franziska , Ramminger Claudia , Schmidt Jennifer , Lwowsky Dominik , Braig Sonja , Dunstheimer Desiree , Ermer Uwe , Gerstl Eva-Maria , Weber Leonie , Nellen-Hellmuth Nicole , Brämswig Susanne , Sindichakis Marina , Tretter Stefanie , Lorrmann Anja , Bonifacio Ezio , Ziegler Anette-G. , Achenbach Peter ,   for the Fr1da Study Group
Published: June 2023

Aims/hypothesis

We aimed to determine whether disease severity was reduced at onset of clinical (stage 3) type 1 diabetes in children previously diagnosed with presymptomatic type 1 diabetes in a population-based screening programme for islet autoantibodies.

Methods

Clinical data obtained at diagnosis of stage 3 type 1 diabetes were evaluated in 128 children previously diagnosed with presymptomatic early-stage type 1 diabetes between 2015 and 2022 in the Fr1da study and compared with data from 736 children diagnosed with incident type 1 diabetes between 2009 and 2018 at a similar age in the DiMelli study without prior screening.

Results

At the diagnosis of stage 3 type 1 diabetes, children with a prior early-stage diagnosis had lower median HbA1c (51 mmol/mol vs 91 mmol/mol [6.8% vs 10.5%], p<0.001), lower median fasting glucose (5.3 mmol/l vs 7.2 mmol/l, p<0.05) and higher median fasting C-peptide (0.21 nmol/l vs 0.10 nmol/l, p<0.001) compared with children without previous early-stage diagnosis. Fewer participants with prior early-stage diagnosis had ketonuria (22.2% vs 78.4%, p<0.001) or required insulin treatment (72.3% vs 98.1%, p<0.05) and only 2.5% presented with diabetic ketoacidosis at diagnosis of stage 3 type 1 diabetes. Outcomes in children with a prior early-stage diagnosis were not associated with a family history of type 1 diabetes or diagnosis during the COVID-19 pandemic. A milder clinical presentation was observed in children who participated in education and monitoring after early-stage diagnosis.

Conclusions/interpretation

Diagnosis of presymptomatic type 1 diabetes in children followed by education and monitoring improved clinical presentation at the onset of stage 3 type 1 diabetes.

Graphical Abstract
Linear correlation between patellar positioning and rotation of the lower limb in radiographic imaging: a 3D simulation study
Authors: Jörgens Maximilian , Brunner Josef , Weigert Maximilian , Bormann Markus , Böhm Elisabeth , Böcker Wolfang , Paulus Alexander C. , Ehrl Denis , Fürmetz Julian
Published: June 2023

Purpose

The purpose of this study was to quantify changes in rotation of the lower limb between image pairs based on patellar position. Additionally, we investigated the differences in alignment between centralized patellar and orthograde‐positioned condyles.

Methods

Three‐dimensional models of 30 paired legs were aligned in neutral position with condyles orthogonal to the sagittal axis and then rotated internally and externally in 1° increments up to 15°. For each rotation, the deviation of the patella and the subsequent changes in alignment parameters were calculated and plotted using a linear regression model. Differences between neutral position and patellar centralization were analysed qualitatively.

Results

A linear relationship between lower limb rotation and patellar position can be postulated. The regression model (R2 = 0.99) calculated a change of the patellar position of − 0.9 mm per degree rotation and alignment parameters showed small changes due to rotation. The physiological lateralization of the patella at neutral position was on average − 8.3 mm (SD: ± 5.4 mm). From neutral position, internal rotation that led to a centralized patella was on average − 9.8° (SD: ± 5.2°).

Conclusion

The approximately linear dependence of the patellar position on rotation allows an inverse estimation of the rotation during image acquisition and its influence on the alignment parameters. As there is still no absolute consensus about lower limb positioning during image acquisition, data about the impact of a centralized patella compared to an orthograde condyle positioning on alignment parameters was provided.

Level of evidence

IV.