Section Width Research Articles

Influence of Lower Double-Track Tunnel Spacing on the Stress and Deformation Characteristics of Upper Tunnel in Double-Level Condominium Tunnels

The open-cut tunnels in Aixi Lake, Nanchang, are constructed in a condominium form of highway tunnel and subway tunnel, which are the first superimposed double-level tunnels in China. The scientific problems faced by this new structure form have attracted the attention of engineers and researchers. If this structure form can be reasonably used, it can reduce the repeated excavation of the ground and reduce the impact of highway tunnel construction on subway tunnels. It is of great guiding significance to study the influence of the spacing between lower double-track subway tunnels on the stress and deformation characteristics of the upper highway tunnel. Based on the model test, the deformation, axial force, bending moment, and earth pressure of the upper highway tunnel are studied. The results show that the maximum displacement of upper tunnel floor can be reduced by 30% when the spacing of the lower tunnel makes the center line of the lower single tunnel coincide with the quadripartite line of the upper tunnel. Horizontal spacing between lower double-track tunnels significantly influences the bending moment of upper tunnel floor but hardly influences the axial force of the upper tunnel floor. Considering the influence of lower tunnel spacing on the earth pressure of the upper tunnel floor, the spacing of the lower tunnel should not exceed 50% of the section width of the upper tunnel.

Effect of lateral misalignment defects of rail joints on dynamic derailment behaviour in railway turnouts

This study aims to investigate the mechanism of wheel jumping derailment in the railway switch panel after a freight wagon passes over a rail joint defect (RJD) situated before the switch. For this purpose, a 3D vehicle-track (turnout) coupled dynamic model that considers the elastic deformation of the rails and wheelsets has been established. Several extreme running conditions, including sharp curves, low-speed railway turnouts, lateral misalignment defects of RJs, and empty wagons are all considered in the simulation model. The vertical wheel rise limit for the railway switch panel is presented for the evaluation of a quasi-static derailment risk. The wheel-rail impact behaviour and the evolution of the derailment processes in the switch panel are revealed, and the effects of wagon load and misalignment width of RJ sections on the vehicle’s dynamic response and running safety are investigated. The results show that the root cause of the high derailment risk in the railway switch is a lower wheel rise limit at the front region of the switch rail when compared with the mainline. This dynamic derailment limit is sensitive to the car-body load and the misalignment width. Severe lateral defects of the RJ before the switch toe should therefore be avoided.

Utilization of Judd-Ofelt theory to assess the photophysical properties of β-keto carboxylate Tb(III) complexes with heterocyclic secondary sensitizer

One binary and five ternary green glowing Tb(III) complexes with β-keto acid as primary sensitizer and heterocyclic aromatic system as secondary sensitizer, were synthesised by an eco-friendly method and characterized via various spectroscopic techniques. The assessment of photoluminescent properties in solid complexes and in solution phase with DMSO as solvent, revealed the bright green emission of complexes on irradiation of UV light due to 5D4 → 7F5 transition, whose intensity persistently increased on insertion of secondary sensitizer. Higher relative quantum yield in ternary complexes communicated the contribution of secondary sensitizers in enhancement of luminescence. Judd-Ofelt parameters (Ω2, Ω4, Ω6) were evaluated from NIR absorption spectra of complexes. Higher Ω2 value in complexes demonstrated the higher covalence character and asymmetry around Tb(III) ion. Radiative, nonradiative transition probabilities, radiative life time, branching ratios and luminescence efficiency were also estimated. Complex T6 reported to have 72.5% efficiency which signalizes superb luminescence performance of this complex. Colorimetric parameters were obtained in solid as well as solution form. Exquisite color purity and CCT value > 4000 K established these complexes as cold green light source. Band gap energy and Urbach band tail, obtained via nonlinear fitting of absorption coefficient, turned out to be in semiconductor range thus can have materiality in various photonic devices. The large value of stimulated emission cross section and narrow full width at half maxima (FWHM) of 5D4 → 7F5 emission peak suggested the prospective use of synthesised complexes as laser media for green color lasers.

Artificial neural network model for predicting the local compression capacity of stirrups-confined concrete

The local compression capacity is a key mechanical property for several constructions, such as the post-tensioned prestressed concrete. Due to the disordered stress distribution caused by the introduction of the concentrated load, it is a huge challenge to predict accurately the local compression capacity of stirrups-confined concrete to avoid the whole structure damage caused by local failure. This study explored a new approach to obtain the local compression capacity for stirrups-confined concrete using artificial neural networks (ANN). The ANN model was trained by a reliable database consisting of 180 samples from previous literature, which had a large application range, covering concrete strengths 15–112 MPa while the stirrup yield strengths 230–660 MPa. The main parameters, including the concrete strength, the local area aspect ratio, the core area aspect ratio, the ratio of duct diameter to the section width, the yield strength of stirrups, and the volumetric ratios of stirrups, were selected as input variables. To evaluate the proposed ANN model, the k-fold cross-validation approach was adopted to determine the generalization and reliability, and the sensitivity analysis was conducted to investigate the importance of the input parameters. Moreover, an empirical ANN equation was generated based on the proposed ANN model for design. Finally, the ANN model and the ANN equation were evaluated and verified against experimental data and existing models. The findings indicated that the ANN approach was highly applicable and reliable for estimating the local compression capacity of stirrups-confined concrete.

Magnetic field induced hair structure in the charmonium gluon dissociation

We study the electromagnetic field effect on charmonium gluon dissociation in quark-gluon plasma. With the effective Hamiltonian derived from QCD multipole expansion under an external electromagnetic field, we first solve the two-body Schr\"odinger equation for a pair of charm quarks with mean field potentials for color and electromagnetic interactions and obtain the charmonium binding energies and wave functions, and then calculate the gluon dissociation cross section and decay width by taking the color electric and magnetic dipole interactions as perturbations above the mean field and employing Fermi's golden rule. Considering the charmonium deformation in a magnetic field, the discrete Landau energy levels make the dissociation cross section grow hair, and the electric dipole channel is significantly changed, especially for the $P$-wave states ${\ensuremath{\chi}}_{c0}$ and ${\ensuremath{\chi}}_{c\ifmmode\pm\else\textpm\fi{}}$. From our numerical calculation, the magnetic field strength $eB=5{m}_{\ensuremath{\pi}}^{2}$ already changes the gluon dissociation strongly, which may indicate measurable effects in high-energy nuclear collisions.

Dimensional accuracy and surface finish of 3D printed polyurethane (PU) dog-bone samples optimally manufactured by fused deposition modelling (FDM)

PurposeThis paper aims to investigate the dimensional accuracy consisting of thickness, grip section width, full length, circularity, cylindricity and surface finish of printed polyurethane dog-bone samples based on American Society for Testing and Materials D638 type V standard, which were optimally printed by fused deposition modelling (FDM).Design/methodology/approachThe experimental approach focuses on determining main effects of printing parameters, including nozzle temperature, infill percentage, print speed and layer height on dimensional error and surface finish of the printed samples, followed by the confirmation tests to warrant the reproducibility of experimental results.FindingsThis study shows that layer height has the most significant impact on dimensional accuracy and surface finish of printed samples compared to other printing parameters, whereas infill density has no significant effect on all sample dimensions.Originality/valueThis paper presents a comprehensive study relating to various dimensional accuracies in terms of full length, grip section width, thickness, circularity, cylindricity and surface finish of dog-bone samples printed by FDM to improve the printability and processibility via additive manufacturing.

Newtonian hydro-thermal fluid fl 1 ow phenomena through a sudden 2 expansion channel with or without baffles

This work aims to study the different characteristics of Newtonian fluid flow and heat transfer througha 1:3 sudden expansion channel with or without plane baffles using the finite volume method. The flowis assumed viscous, incompressible, steady, and laminar. The different characteristics of hydro-thermalfluid flow phenomena have been studied for 𝑅𝑒 ∈ [0.1 − 200] to demonstrate the influence of thepresence of baffles. The profiles of velocity, pressure, skin friction coefficient, friction factor, averageNusselt number, and pumping power have been examined for both the cases of the presence and absenceof baffles. It has been observed that the hydro-thermal characteristics become more pronounced withthe increase in the number of baffles. In the case of three baffles of equal length, at 𝑅𝑒 = 200 it iscalculated that if the thickness of the baffles is same and equal to 10% of the length, then the value of Nu becomes approximately 1.2 times of that in the absence of baffle. For the same value of Re, ithas been found that for the presence of one baffle of length equal to the width of the inlet section of thechannel and of thickness 10% of the same, the value of 𝑁𝑢􀯔􀯩 becomes 1.11 times of that in the absenceof baffle, while in the case of three baffles of equal length and of equal thickness like the abovementioned case of one baffle, the value of 𝑁𝑢􀯔􀯩 becomes 1.25 times of that in absence of baffle. It hasalso been revealed that the enhancement of thermal phenomena increases with the increase inthe baffle’s height.

Seismic Performance Analysis of Segmental Assembled Concrete-Filled Steel Tubular Pier with External Replaceable Energy Dissipation Ring

In order to develop a new type of prefabricated bridge structure system with green, efficient and recoverable function, which complies with the new requirements of rapid repair of pier function after earthquake, and improves the applicable performance of prefabricated assembled pier in medium and high-intensity seismic areas, a precast segmental concrete-filled steel tubular (PSCFST) pier with an external energy dissipation ring is proposed. Based on ABAQUS analysis software, a four-segment PSCFST pier model is established, and the pseudo-static comparative analysis is carried out between the traditional PSCFST pier and the PSCFST pier with the external energy dissipation ring. The results show that compared with the traditional PSCFST pier, the lateral bearing capacity of the PSCFST pier with an external energy dissipation ring is increased by 60%, the energy dissipation capacity is increased by about 20 times, and the damage is concentrated in the energy dissipation ring, the damage is controllable, and the rapid repair after the earthquake can be realized by replacing energy dissipation devices and other measures. At the same time, the seismic performance of pier models with three different control parameters (initial prestress, material strength of energy dissipation ring and section width of energy dissipation ring) under reciprocating loading is analyzed. The results show that the initial prestress does not affect the cumulative energy consumption of the pier; the increase in the material strength of the energy dissipation ring improves the overall stiffness and improves the energy dissipation capacity of the PSCFST pier; the reduction in section width will affect the overall equivalent stiffness and unloading stiffness of the segmental pier, and the energy dissipation capacity will be significantly reduced.

Study of the effect of the cross profile of cold rolled strips on the occurrence of flatness defects

The paper considers the influence of the profile of cold-rolled steel, obtained on a multi-stand continuous mill, on one of the main factors in the quality of the shape of a steel strip - the flatness index (non-flatness amplitude and type of defect). For this, the existing model of the formation of the steel strip flatness was used, which takes into account the main factors of rolling and makes it possible to determine the shape of the cross section and the amplitude of the flatness defect of finished steel strips. With the help of the mentioned model, the thickness of the cold-rolled strip along the section width is calculated, and its non-flatness is also determined. Using methods of mathematical statistics, the effect of partial reduction in the last stand of the mill and the convexity of the crosssectional profile of the finished strip on flatness indicators has been established, and limitations on the values of these factors have been determined. A cold rolling mode is proposed on a five-stand mill 1700 of PJSC Severstal, which ensures the production of a strip of a high category of flatness, due to the optimal choice of the distribution of partial reductions over the stands. Introduction of the proposed mode, as well as the modes determined using the created flatness assessment methodology, will reduce the level of rejection by flatness defects to 1–1.5% of the current level.

Simulation and Experiment of the Spiral Digging End-Effector for Hole Digging in Plug Tray Seedling Substrate

Usually the planters used in agricultural machinery face two problems: The planters have to spread the soil twice using the tray seed planter, and it is difficult for them to dig the holes before planting. This study has designed a spiral digging end-effector to dig holes in parallel effectively and quickly so that the seeds can be planted in the holes easily. A spiral digging end-effector was designed with five spiral bits, a synchronous belt, a cylinder, a gear motor, and a connecting plate based on the tray size and the pumpkin seed characteristics. Before the optimization of the end-effector’s parameters, the substrate discrete element model parameters were calibrated using the method of “material funneling” applied for the EDEM discrete element model simulation. The contact parameters and model parameters (substrate–substrate static friction coefficient, substrate–substrate rolling friction coefficient, and surface energy) that have significant impacts on the substrate AOR (angle of repose) were selected by applying the Plackett–Burman Design and the path of steepest ascent method, and their respective optimal value range were determined. The optimal parameter values were obtained through the Central Composite Design response surface analysis test, and the parameters of the spiral digging end-effector were optimized combining the substrate particle simulation. The verification test results indicate that the substrate discrete element model parameters were accurate and reliable if the substrate static friction coefficient was 0.427; the substrate rolling friction coefficient was 0.039, and the surface energy was 0.228. When the cone angle is 30°, the spiral angle is 80°, and the rotational speed is 240 r/min, the section width at the hole depth of 13 mm is 23.1 mm, and the particle overflow proportion is about 2.05%. Compared with the protrusions penetrating end-effector, soil porosity is increased, and soil aeration is improved. Therefore, the spiral digging end-effector can effectively and quickly dig holes in the seedling substrate and can sow pumpkin seeds, which provides a research basis for the design and improvement of automatic pumpkin seed sowing equipment.

Excitation of quantum systems by short laser pulses: The effect of the pulse shape and durations

We present a simple universal approach for the description of the quantum system excitation by short laser pulses in terms of the probability during the action of a pulse. Our attention is focused on the probability dependence on the pulse duration for different pulse envelopes and detunings of the carrier from the resonance frequency. We considered Gaussian, super-Gaussian, sin2 and rectangular envelopes and a Gaussian spectral profile of the excitation cross section. It is shown that the excitation probability as a function of the pulse duration is of various characters, changing from monotonic to oscillating depending on a pulse shape, a carrier frequency detuning from the resonance, and a spectral width of the cross section, in contrast to the prediction of the standard perturbation approach based on the Fermi golden rule.

Development of an experimental apparatus for flat plate drag measurements and considerations for such measurements

Accurately measuring small changes in aerodynamic drag over a flat surface stands at the core of the development of technologies capable of reducing turbulent friction drag. A wind tunnel drag measurement system was developed which improves significantly on the state of the art. Experimental tests demonstrated that an uncertainty of less than 0.5% of C D at a 95% confidence level was typically achieved, already at drag values below 1 N. This was replicated in two different wind tunnels. A match with literature on riblet performance within 1% of C D was obtained. A crucial aspect of the design is the implementation of a correction for the pressure forces on the streamwise-facing surfaces of the test plate assembly. The flexible architecture of the system in the present realisation makes it suitable for most wind tunnels having a test section width of 400 mm or larger, which allows for accelerated development of turbulent drag reduction concepts from moderate-size low-cost facilities towards flow conditions relevant to the intended industrial application.

A comparison of machine learning- and regression-based models for predicting ductility ratio of RC beam-column joints

Seismic response of Reinforced Concrete (RC) beam-column joints has always been evaluated by researchers due to their undeniable influence on the overall behavior of RC building frames under seismic loads. In the present study, an attempt has been made to predict displacement ductility ratio of RC joints using machine learning- (Artificial Neural Network and Random Forest) and regression-based (linear, nonlinear and ridge) methods. Therefore, a dataset including the results of over 170 experimental studies conducted on RC joints was collected from the international peer-reviewed publications. Parameters reflecting beam and column dimensions (length, cross section width and depth), reinforcement detailing (longitudinal and transverse reinforcement of beams and columns), material properties (concrete compressive strength, yield strength of longitudinal and transverse reinforcement) and retrofitting techniques were considered as input variables for predicting the only output parameter, displacement ductility ratio. The predicted and actual values were compared together and the efficiency of the models was assessed by Taylor diagram and performance metrics including RSME, MAE, MAPE and R2. The evaluation results proved the high reliability of proposed models for predicting ductility of RC joints.

Measuring the density of the fissula antefenestram and the section of the basal turn of the cochlea: Are they useful in the radiological diagnosis of otosclerosis?

IntroductionThe role of objective parameters in terms of improvement of the accuracy of high-resolution computed tomography (HRCT) of the temporal bone in the diagnosis of otosclerosis remains unclear. ObjectivesTo investigate the relationship between the density of the fissula antefenestram (FAF) and of the width of the transversal section of the basal turn of the cochlea (BTC), and the diagnosis of otosclerosis. MethodsThis is a retrospective study in which preoperative HRCT data from ears of patients submitted to stapedotomy due to otosclerosis (case group) were evaluated. For the control group, normal hearing ears having undergone HRCT for other purposes were included. Case and control HRCT images were objectively assessed by an experienced blinded radiologist. During this evaluation, measurements of the relative radiological density of the FAF and of the transversal section of the BTC were obtained. The results were compared between the groups. Also, a receiver operating characteristic curve was created and the area under the curve (AUC) was calculated for each variable. Significance level was set at .05. Results40 ears were included in each group. Case ears presented reduced values for the relative radiological density on the FAF (p-value<0.0001). Moreover, ears with otosclerosis (p-value: 0.022) presented lower transversal section of the BTC. The AUC for these variables reached 0.929 and 0.646, respectively. ConclusionsOtosclerotic ears present reduced radiological density on the FAF and narrower BTC. The relative density of the FAF also shows a great diagnostic power in the context of this disease.

Study and Design Analysis of Hazard Removal and Reinforcement Scheme of a Bridge Diversion Sluice

Most of the existing sluices in China have been in operation for more than 40 years, and the aging problem is becoming increasingly prominent. The selection of reinforcement schemes for sluices in vulnerable conditions is of great significance to the whole project. A reasonable reinforcement scheme can ensure their safe operation and reduce unnecessary resource investment. This study focuses on the diversion gate of a bridge in China that through aging has emerged insufficient capacity of downstream energy dissipation and scour prevention, severe scour of the diversion dike foundation, and insufficient flood control and rescue capacity. Two reinforcement schemes are examined by analyzing the engineering parameters of the bridge diversion sluice and the necessity of engineering construction, namely, raising the flood discharge level and increasing the width of the overflow section. In this study, Super Decisions software was first used to simulate the reinforcement scheme of the bridge diversion sluice, calculate the weight of the factors, and obtain the optimization scheme from the two aforementioned reinforcement schemes, which was based on the analytic network process (ANP), and the related factors affecting the reinforcement scheme of the bridge diversion sluice are determined and evaluated. The relevant calculation and analyses of the optimization scheme are conducted using ANSYS finite‐element software. The selection process of reinforcement scheme for such sluices provides a reference for other similar projects.

Research on vibration reduction test and frame modal analysis of rice transplanter based on vibration evaluation

The chassis of rice transplanter tends to vibrate severely in the severe working environment, causing a severe effect on the operational performance and driving comfort. In order to avoid this situation, this paper constructs a vibration evaluation system of the rice transplanter and carries out experimental analysis. According to the optimal acceleration sensor placement scheme, a test platform system was designed. Taking the high-speed transplanter chassis as the research object, this study carried out the experiments modal analysis and optimization on the chassis. The three-dimensional model of the transplanting machine chassis established by SolidWorks was imported into ANSYS Workbench for finite element modal simulation analysis. Comparing the two modal analyses, it is found that the results data of the two analysis methods were very close. After optimization, the length x1, the section width x2 and the thickness of the hollow beam x3 of the main load-bearing beam of the frame were as follows : x1=1641.5 mm, x2 =26.7 mm, x3=5 mm, respectively. The maximum overshoot of the low-level system was reduced by 28.57%. It has been verified that the vibration of the whole machine has been effectively reduced. Keywords: chassis, high-speed rice transplanter, vibration evaluation, modal analysis DOI: 10.25165/j.ijabe.20221504.7244 Citation: Jin X, Cheng Q, Tang Q, Wu J, Jiang L, Wu C Y, et al. Research on vibration reduction test and frame modal analysis of rice transplanter based on vibration evaluation. Int J Agric & Biol Eng, 2022; 15(4): 116–122.

Investigation of temperature distribution performances of three different heat exchanger models for exhaust gas waste heat energy recovery system used with thermoelectric generator in gasoline engines

In this study, examination of the temperature distribution for three different heat exchanger models for exhaust gas waste heat recovery systems to be used in internal combustion motorcycle engines has been made. Simulations of the models have been made by means of ANSYS Workbench Fluent software and comparative results have been put forward. It has been taken into consideration that the selected heat exchanger models have generable geometries. Model no. 1 is inclined to the outlet from the inlet by 5o, model no. 2 has three steps each of which has a gradient of 20o, and model no. 3 has a fixed section width which is parallel to exhaust gas transfer. Moreover, in model no. 3, a heat sink has been placed into the exhaust gas. On cold surfaces, the highest and the lowest temperatures have been measured respectively as 337.937K and 329.465K in model no. 1, as 342.875K and 329.639K in model no. 2, and as 363.897K and 354.995K in model no. 3. The difference between the lowest and the highest temperatures is observed as in models no. 2 and 3. With relation to the temperature distributions on hot surfaces of TEGs, the lowest and the highest temperatures are respectively as 508.631 K and 402.742 K in model no. 1, as 510.092 K and 409.632 K in model no. 2, and as 536.595 K and 510.633 K in model no. 3 It has been observed that the lowest difference of temperature occurred in model no. 3. When the results are examined, it is seen that the best temperature difference and the highest temperature value have been achieved in model no. 3.

Franklin Collinear Antenna 2 Levels Different Sides using Array Method 4 Stacking Units 360ᵒ with Integrated Reflector and Power Combiner for ADS-B S-Receiver Mode

In this study, an antenna system that could cover the 360ᵒ detection area using the microstrip method was created. The antenna design proposed uses the franklin collinear method with the addition of an array of arms to the left and right of the antenna and the addition of reflectors as a gain enhancer. The four antenna array units are combined using a power divider (combiner) as a unifying antenna. Antenna design with end fire radiation pattern cannot be used in receiving the ADS-B antenna system, because it works only in certain sectors with certain beamwidth, so it needs to be modified by adding an array of 4 units that make up 360◦ radiation of directional diagrams. The addition of the reflector is done by testing the optimum width. The most optimum width is obtained by the width of the side addition on the side of the antenna aperture cross section width of 80 mm. Based on the results of experiments that have been carried out for the design of receiver antennas for ADS-B applications that are required in the form of a radiation pattern in all directions using the reflector technique, the most appropriate gain increase is to use a phase difference for the antennas that are closest both left and right by 90o in ¼ λ conditions in the integration process using a 4 way power combiner. Response return loss at frequency 1.0752 GHz and 1.109 GHz is -15 dB, it means antenna has 33.8 MHz bandwidth with maximum response return loss at -23.22 dB and gain of 7.586 dBi, this antenna design is very suitable for use in the ADS-B application. Design and simulation at this antenna used CST software.

Optimization of 3D Printing Parameters of Biodegradable Polylactic Acid/Hydroxyapatite Composite Bone Plates.

The building parameters of three-dimensional (3D) printed polylactic acid/hydroxyapatite (HA) composite bone plates were optimized by an orthogonal experiment, and the effects of the layer thickness, printing speed, filament feeding speed, and HA content on the bending strengths of the specimens were analyzed. The deformation characteristics of the specimens were studied by 3D full-field strain analysis, and the internal defects of the specimens were analyzed. The effects of different combinations of the process parameters on the cross-sectional shape of the single deposited line, printing temperature, and pressure of the molten material were further analyzed. The results showed that the factors affecting the bending properties were the layer thickness, printing speed, filament feeding speed, and HA content, successively. The optimized process parameters were an HA content of 10%, a layer thickness of 0.1 mm, a printing speed of 30 mm/s, and a filament feeding speed of 0.8 mm/s, and the optimized specimen bending strength was 103.1 ± 5.24 MPa. The deposited line with a flat section shape and width greater than the print spacing helped to reduce the porosity of the specimens. The process parameters that resulted in large high-temperature areas and a high extrusion pressure could better promote material fusion.

Experimental study on the tensile response of post‐installed adhesive anchor connections in reinforced and plain concrete beams

AbstractPost‐installed connections are widely used in the rehabilitation, strengthening, and expansion of existing concrete structures. These connections accommodate the connecting of new elements to old concrete using post‐installed anchoring techniques. Attachment of new segments to concrete beams and columns requires the installation of anchors in slim concrete components. Under this condition, the behavior of connection is severely affected by the small width of concrete elements. Additionally, the behavior of anchors is influenced by the confining effects of stirrups in reinforced concrete elements. In this paper, the tensile behavior of chemical anchor connections in single and group formations of four and six anchors is investigated using the results of 36 individual experiments of adhesive anchors installed in plain and reinforced concrete beams. The key design parameters are embedment depth, section width, and effects of the reinforcement. The results indicate high levels of interaction between all studied parameters. The tensile capacities of the single and groups of anchors are compared against ACI 318 predictions. The main effects of parameters, as well as their interactions, are analyzed and discussed. Based on the test results, several recommendations are provided for the installation of adhesive bonded anchors in narrow concrete components.