Multi Section Research Articles

Settlement control in large span tunnels under shallow over burden: a case study of the Arash-Esfandiar-Niayesh tunnel

Settlement control is pivotal in the construction of large span tunnels, particularly when situated under shallow overburden. The importance of settlement control in the context of the Arash-Esfandiar-Niayesh tunnel project, a multi section tunnel designed to facilitate two-way traffic in Municipality of Tehran District 3, is studied. The tunnel, which possesses an overburden of 4–15 m, faces unique challenges such as low overburden, urban location, and proximity to tall structures. By integrating the New Austrian Tunneling Method (NATM), this paper examines the effects of various support systems on construction of the tunnel project. Two critical sections are analyzed, and the settlement control strategies are examined according to a combination of various support elements. Analysis and numerical modeling based on PLAXIS 2D finite element code revealed the impact of these support systems on ground settlements on the structural and geotechnical stability. They had a substantial impact of tunnel geometric shape on sustainability and stress distribution. The inadequacy of common support systems, especially in tunnels with a horseshoe section, is highlighted. The impact of removing temporary lattice girderson surface settlements emphasizes the importance of settlement monitoring. Field data, including a maximum vertical displacement of 2.6 cm on the ground and in the tunnel, validate the numerical analysis results. Despite the challenges, the consistency between numerical and instrument data underscores the effectiveness of settlement control strategies.

Sections and Unirulings of Families over $\mathbb{P}^{1}$

AbstractWe consider morphisms $\pi : X \to \mathbb{P}^{1}$ of smooth projective varieties over $\mathbb{C}$. We show that if π has at most one singular fibre, then X is uniruled and π admits sections. We reach the same conclusions, but with genus zero multisections instead of sections, if π has at most two singular fibres, and the first Chern class of X is supported in a single fibre of π.To achieve these result, we use action completed symplectic cohomology groups associated to compact subsets of convex symplectic domains. These groups are defined using Pardon’s virtual fundamental chains package for Hamiltonian Floer cohomology. In the above setting, we show that the vanishing of these groups implies the existence of unirulings and (multi)sections.

Research on the design and balancing strategy with multi-section lithium battery protection IC

This study uses 0.5um BCD technology to design a multi section lithium battery protection chip suitable for small mobile electronic devices such as Bluetooth earphones and smart bracelets. By providing a complete system structure diagram, the principles and design methods of several key circuits in the chip were introduced. This chip can effectively monitor the voltage of lithium batteries, take protective measures against abnormal situations such as overcharging, discharging, and overcurrent, and has a balancing module with dynamic power consumption management function. The balancing module adopts a passive balancing architecture, and the balancing algorithm used is an average based voltage detection algorithm. Using this algorithm can make the balancing system structure simple and reduce system power consumption, reduce the differences between batteries within the group, and thus improve the uniformity of the battery pack. The overcharging detection accuracy of the designed chip is ±25mV, the overcharging detection accuracy is 50mV, and the static working current of the chip is 7uA.

Experimental Study on Wind Speed Distribution in Semi-circular Arch Tunnels Based on Mirror Stepped Grid Method

Ventilation is the cornerstone of coal mine safety production. Accurate monitoring of ventilation parameters is the basic guarantee for ventilation technology decision. For the problem that the accuracy of wind speed monitoring in coal mine tunnels is difficult to meet decision-making needs, a combination of theoretical calculation and experimental research was used to study the relationship between the average wind speed line and the position of the tunnel wall. The theoretical calculation obtained the expression of the relationship between the average wind speed line of the semi-circular arch tunnel section and the position of the tunnel wall. The proposed multi section mirror stepped grid format was used to investigate the airflow field in a semi-circular arch roadway under different conditions in the laboratory. The contour map of wind speed distribution was drawn, and the position of the measured average wind speed line was obtained. The absolute error between the measured average wind speed line and the theoretical model calculation results was within 5%, which verified the reliability of the theoretical calculation results.

United composite strength calculation method for special-shaped CFST columns with multiple cavities

The present study investigates the method of calculating the composite strength of special-shaped concrete-filled steel tube (CFST) members with multiple cavities. Based on the research findings of CFST unified theory and some tests, a quantitative method to evaluate the concrete constraint effect is proposed for cross-sectional shapes ranging from regular triangles, squares…regular octagons to circles. The cross-sectional composite strength of regular polygonal CFST members is determined by the way dividing the concrete into effective and ineffective constraint regions, discounting constraint coefficients, and applying unified formulas. Additionally, a regression analysis is conducted to establish the relationship between interior angles and constraint effects. Subsequently, using quadrangle CFSTs as an example, this study investigates the relationship between cross-sectional regularity and constraint effect, and proposes a composite strength calculation method related to it. Finally, the special-shaped multi cavity cross section is separated into several simple polygonal cross sections, taking into account shape efficiency and regularity, to calculate the composite strength of each cavity CFST member and summarize them for determining the total axial compressive bearing capacity. The research findings indicate that a linear relationship exists between the interior angle of the cross section and the initial tangent line angle of the second-degree curve, which serves as the boundary between effective and ineffective constraint regions in regular polygonal steel tube confined concrete. The proposed unified composite strength calculation method, specifically designed for special-shaped CFST columns with multiple cavities, can accurately predict their actual strength.

A novel approach to the design of multi section ultra-wideband Jaumann absorber

A novel ultra-wideband Jaumann absorber design and analytical procedure that greatly enhance the absorption bandwidth and absorptivity level using few dielectric layers are described. The absorptivity bandwidth of the proposed structure is much better than the traditional absorbers. In Jaumann absorbers, determining resistivity of resistive sheets is a complex task and optimization techniques are generally utilized for the solution. The new contribution given in this paper is that the reflected waves from each boundary inside the dielectric layers are eliminated. Therefore, input reflection coefficient is obtained analytically using Binomial expansion without any approximation. Then a binomial matching procedure is applied to obtain the ultra-wideband absorption. Absorption enhancement is achieved by quarter wavelength dielectric slabs, resistive sheets with critical resistivities and a metallic ground plane backed final dielectric layer with high permittivity. Proposed structure is designed for normal illumination. Parallel and perpendicular polarizations are also studied for oblique incidences. Absorptivity and reflectivity variations are presented versus frequency in 0–40 GHz band for the 20 GHz design frequency for several structures. It is shown that choosing three layers backed with a final layer (εrb=20) structure gives absorptivity greater than 90% in a 6.8–33.2 GHz band region with a fractional bandwidth of 132%. CST Microwave Studio and AWR programs are used to prove the correctness of the proposed method. Great consistency is observed and demonstrated in the numerical results section.

A new approach to design multi section wideband transmissive absorber using thin resistive sheets and dielectric slabs

A new design and analytical procedure are presented that greatly enhance the absorption bandwidth and absorptivity level with few dielectric layers without using the metallic ground plane. The performance of the proposed structure is beyond what is possible with Salisbury screen or Jaumann absorber. The performance improvement is obtained using the resistive sheets coated on the surface of each lossless dielectric slab. Reflected waves inside each dielectric layer are eliminated and input reflection coefficient can easily be written with the aid of binomial expansion without any approximation. So we can apply Binomial design and considerable improvement at the absorption level and bandwidth is realized by the selection of the resistive sheets with the critical resistivity values. Alternatively, we observed that transmission is independent from frequency and layer number and it can be controlled only by the initial and final layer’s dielectric constants. Two cases are analyzed as air to air and air to dielectric. Absorptivity, transmittivity and reflectivity variations are presented versus frequency in 0–20 GHz band, in both cases. It is shown that choosing three layers backed with a final layer (εrb=20) structure in air to air case gives absorptivity greater than 90% in 5.45–14.55 GHz band where fractional bandwidth is 91% at 10 GHz design frequency. The design is performed at normal incidence and also wide angular stability at a reasonable level is presented. CST Microwave Studio and AWR simulation programs are also used to prove the correctness of the proposed method.

Optical properties of multilayer Er-doped Ga1As39S60 chalcogenide glass thin films deposited by spin coating

In order to produce spin-coated chalcogenide glass thin films with higher thickness and lower residual solvent, multilayer lamination of 0.85 at.% Er-doped Ga1As39S60 chalcogenide glass was studied. Er was doped into the Ga1As39S60 glass by melt quenching technique. Solutions for spin coating were prepared from glass powders dissolved in propylamine at a concentration of 0.2 gr/ml. Films with 1–4 layers were spin coated using multiply deposition/two step thermal stabilization procedure. The average thickness for each layer was about 0.48 μm as the 4-layered sample was 1.76 μm thick. Influence of multilayer lamination on optical parameters of films and the amount of residual solvent was studied by examining UV visible infrared spectroscopy. According to AFM images, surface roughness of layers decreased with increasing number of layers from 3.6 nm to 0.78 nm. No interfaces were observed from SEM images of multi layered cross section. Although all of the films demonstrated PL emission at 1.55 μm, emission slightly decreased with increasing the number of layers.

General compensation control method of flexible manipulator driven by tendon-sheath mechanism

Flexible manipulator has been widely used because of its flexibility. In addition, the tendon-sheath mechanism has the advantages of compact structure and strong flexibility, and it can be used as the driving transmission mode of the flexible manipulator. However, the nonlinear and hysteretic characteristics of the tendon-sheath mechanism directly affect the motion accuracy of the manipulator. Firstly, the kinematic and static models of the flexible manipulator are analyzed considering the influence of multi section coupling. In addition, the mechanical transmission process of the tendon-sheath mechanism is analyzed. On this basis, a general feedforward compensation method for the flexible manipulator is established. The proposed model-based compensation control method can be applied to all flexible manipulators, and it is of great significance to promote the practical application of the manipulator.

Hovering Locomotion for UAVs With Thrust-Vectoring Control Surfaces

This letter presents a working prototype of a quad-rotor with control surfaces positioned in the propulsive slipstreams. The control surfaces provide a unique potential to redirect the air flow from the propulsion systems and produce lateral forces at a level attitude. This approach to locomotion has many useful applications in different areas of aerial sensing. Furthermore, the mechanical approach of using control surfaces for this purpose is unique, to the best of the authors’ knowledge; until this point, most aerial robot designs that have this locomotion capability make exclusive use of motors and propellers to exert lateral forces. The use of control surfaces in a propeller slipstream poses a potentially useful actuation mode for aerial vehicle designs that have control surfaces. The letter investigates lateral forces from redirected slipstreams as part of a larger development of the Multi-Section (MIST) Unmanned Aerial Vehicle at the University of Minnesota. The paper connects theoretical models with experiments on a testbed and a working prototype that demonstrate feasibility and characterize the force-production capability of slipstream-washed control surfaces.

Fiber Optic Network Technology of Communication of Specialists via Mental Neurointerfaces

Resonance communication of specialists can be carried out at a distance in real time in dialogue mode through a mental neurointerface with two-way communication. Mental neurointerface on the principles of magnetic resonance tomography captures a hologram of brain activity of the internal speech of the inductor specialist and transmits it to the mental neurointerface of the recipient's interlocutor through ultra-sensitive multi section nano resonators waveguides. The mental neurointerface of the recipient's interlocutor perceives the transmitted hologram of the brain activity of internal speech and resonates its internal speech to it. An interlocutor of the recipient with equivalent semantic memory in a resonant way makes sense of the internal speech of the inductor specialist. He forms the response with internal speech and transmits it to the interlocutor with his mental neurointerface through nano resonators in the form of holograms of the brain activity of internal speech. Interlocutors, as specialists in one subject area, have a similar semantic memory. Semantic memories are considered similar if they correspond to the principle of gold section according to a professional thesaurus. Specialists and interlocutors must learn a professional thesaurus before starting a dialogue through mental neurointerfaces. Thus, the problem of transmitting and reading thoughts at a distance using high technology is solved, taking into account the psychological aspects of the interlocutors. The development of mental neurointerfaces and ultra-sensitive multi section nano waveguide resonators for transmitting holograms of internal speech brain activity is just beginning. The use of resonant communication by mental neurointerfaces through nano waveguides resonators waveguides is currently very relevant in many areas of life activity.

Evaluation of the Effect of Stray Current Collection System in DC-Electrified Railway System

Stray current corrosion damage is significant in DC traction power supply system (DTS). Stray current collection system including stray current collection network (SCCN) and stray current drainage device (SCDD) is designed to control the stray current. A comprehensive system integrated calculation model is established to evaluate the stray current. And the iterative power flow algorithm with simplification of DTS is proposed. The stray current distribution is calculated by multi sections rail reflux system model. The model is verified with CDEGS simulation. The influence of stray current collection system on stray current is evaluated. The result shows that the primary stray current is mainly affected by rail to SCCN resistance and the length of the line. The efficiency of collecting stray current of SCCN is mainly affected by the resistance of SCCN and the SCCN to earth resistance. While the use of SCDD deteriorates the efficiency of collecting stray current of SCCN. A site test was carried out in Chengdu Metro Line 1 to evaluate the effect of stray current collection system.

Optimization of wing structure using carbon fibre on a combined shell blended wing body

Composite materials have many advantages in macro materials and nanomaterials. The strength of composite material is fully based on the orientation of ply. This research deals with the pressurized inner wing. Such design of the wing and fuselage remains a significant challenge for Flying Wing aircraft. Since the inner wing is nearly rectangular, it is relatively inefficient to resist the pressure loads by bending that consequently brings weight penalty. The wing structure was evaluated by using carbon fibre material at different orientations on fabric. To reduce this weight penalty of the wing, the internal multi-shell structure was combined to form a boxed multi bubble section configuration. The novel section was modelled and the structural properties were evaluated.

Resonance Technology of Communication of Specialists via Mental Neurointerfaces

For a long time, humanity takes up the problem of transferring thoughts over a distance. It can be solved using high technology. Resonance communication of specialists can be carried out at a distance in real time in dialogue mode through a mental neurointerface with two-way communication. Mental neurointerface on the principles of magnetic resonance tomography captures a hologram of brain activity of the internal speech of the inductor specialist and transmits it to the mental neurointerface of the recipient's interlocutor through ultra-sensitive multi section nano resonators waveguides. The mental neurointerface of the recipient's interlocutor perceives the transmitted hologram of the brain activity of internal speech and resonates its internal speech to it. An interlocutor of the recipient with equivalent semantic memory in a resonant way makes sense of the internal speech of the inductor specialist. He forms the response with internal speech and transmits it to the interlocutor with his mental neurointerface through nano resonators in the form of holograms of the brain activity of internal speech. Interlocutors, as specialists in one subject area, have a similar semantic memory. Semantic memories are considered similar if they correspond to the principle of gold section according to a professional thesaurus. Specialists and interlocutors must learn a professional thesaurus before starting a dialogue through mental neurointerfaces. Thus, the problem of transmitting and reading thoughts at a distance using high technology is solved, taking into account the psychological aspects of the interlocutors. The development of mental neurointerfaces and ultra-sensitive multi section nano waveguide resonators for transmitting holograms of internal speech brain activity is just beginning. The use of resonant communication by mental neurointerfaces through nano waveguides resonators waveguides is currently very relevant in many areas of life activity.

Performance Evaluation of Neuro Fuzzy Clustering for Hydro Thermal Power System

To meet increasing power demands and reduce carbon emission additional renewable sources of power are added to existing thermal unit. Even network frequency change by 1% due to change in speed, may result in loss of synchronization with the rest of power system and finally resulting in power system black-out. Inter-connection of hydro units to existing thermal system can allow to transmission system to operate at full capacity. The paper investigates LFC by adding non-linearity’s to the thermal and hydro-thermal systems. Further PID and Neuro-Fuzzy Controllers are compared for these systems . A multi section steam turbine with re-heater was used for a single area system modeled in MATLAB, later two single area systems were combined to create a two area system, and its dynamics are studied by creating load perturbations. Form simulation studies it is shown that the proposed Neuro-Fuzzy controller was able to attain a setting time of 10 Sec which is comparatively lower than other existing speed controllers. The time domain response result of hydropower system proves that it provides more rapid output response and minimal overshoot.

Lossless WDM PON Photonic Integrated Receivers Including SOAs

The role of a semiconductor optical amplifier (SOA) for amplifying downstream traffic at optical network terminals (ONT) within a silicon-photonics integrated receiver in a high capacity passive optical network (PON) is investigated. The nearly traveling wave SOA effects are evaluated by considering fabrication and link loss constraints through numerical analysis and experimental validation. The impact of hybrid integration of a SOA chip on a silicon on insulator (SOI) photonic chip using the flip chip bonding technique on SOA design is evaluated through numerical analysis of a multi section cavity model. The performance of the proposed ONT receiver design employing twin parallel SOAs is evaluated experimentally on a 32 × 25 Gb/s OOK WDM transmission system considering cross gain modulation (XGM) and amplified spontaneous emission (ASE) constraints. The XGM impact is evaluated through 32 channel wavelength division multiplexing (WDM) transmission and a likely PON worst case scenario of high channel power difference (~10 dB) between adjacent channels. The impact of ASE is evaluated through the worst-case polarization condition, i.e., when all of the signal is coupled to only one. Successful transmission was achieved in both worst-case conditions with limited impact on performance. SOA results indicate that a maximum residual facet reflectivity of 4 × 10−4 for the chip-bonded device can lead to a power penalty below 2 dB in a polarization-diversity twin SOAs receiver.

Numerical simulation of aerodynamic characteristics of multi-element wing with variable flap

Based on the Reynolds averaged Navier-Stokes equation, the mesh generation technique and the geometric modeling method, the influence of the Spalart-Allmaras turbulence model on the aerodynamic characteristics is investigated. In order to study the typical configuration of aircraft, a similar DLR-F11 wing is selected. Firstly, the 3D model of wing is established, and the 3D model of plane flight, take-off and landing is established. The mesh structure of the flow field is constructed and the mesh is generated by mesh generation software. Secondly, by comparing the numerical simulation with the experimental data, the prediction of the aerodynamic characteristics of the multi section airfoil in takeoff and landing stage is validated. Finally, the two flap deflection angles of take-off and landing are calculated, which provide useful guidance for the aerodynamic characteristics of the wing and the flap angle design of the wing.

Research on Control Technology of Concentrated Coal Mine Rail Transport Intelligence

<p class="p1"><span class="s1">Based on a matrix of interlocking control strategy, industrial plc control technology, field bus communication technology of mine shaft orbit transportation intelligent centralized control technology and implementation method are introduced in this paper. Line operation using the multi section partition method to draw intuitive control strategy, simplifying the interlock logic, to realize the intelligent management and dispatching of the railway train, improve transport efficiency; application of plc and fieldbus technology improves the stability and reliability of the system operation, convenient underground site operation personnel and ground remote scheduling scheduling staff to keep abreast of the train running state, issued instruction scheduling, to ensure the smooth of mine transportation operation. Promote the automation and intelligent development of coal transportation, to improve the level of information technology in coal mine production scheduling, decision-making is of great significance.</span></p>

The impact of distributed power sources to the best of flow in electrical networks

Intensive implementing distributed generation sources from alternative energy sources leads to a situation where one feeder can connect several different types of distributed energy sources, including solar power plant and small hydropower plant. The system consists of distributed generation small-capacity power plants scattered throughout the energy system. They supply electricity to consumers in the near and in the case of excess energy can transfer its network centralized power. This paper discusses the reduction of active power losses in the local electrical systems that operate different types dispersed energy sources. The main goal is to develop a methodology for determining the point of power flow section the local electrical system of dispersed generation sources and develop a method for choosing the optimal place network disconnection criterion of active power losses. The article shows the computer model regime for local electricity system that allows to determined the place point of power flow section and calculated the power loss at section schemes in the respective nodes. The choice of multi sections is difficult optimization problems. It is proved that in the use of multiple distributed sources of energy in the local electrical system for optimum energy losses point of power flow section (several possible points of power flow section) is selected at the lower junction voltage. Regulation of power generated by small hydroelectric power plant affects the change point of power flow section local electric networks and reduces the active power losses in the local electrical system

WYBRANE ASPEKTY MODELOWANIA ŚLIMAKA GLOBOIDALNEGO W ŚRODOWISKU CATIA

The paper presents methods of modelling the globoid worm with rectilinear profile using CATIA system. The methods of modelling of globoid surface, among others throw extending a profile accross the screw lines of globoid (Sweep), by making the surface as multi section (Multi Section Surface) are specified. Some steps by modelling the globoid surface are automated by writing macros in the CATIA system. The accuracy of the models of globoid worms obtained by different methods is presented. The capabilities of the CATIA system by modelling are presented.