The effect of right versus left long-term single-sided deafness on sound source localization

Purpose:To analyze the effect of right versus left long-term single-sided deafness(SSD)on sound source localization(SSL),discuss the necessity of intervention and treatment for SSD patients,and analyze the therapeutic effect of long-term unilateral cochlear implantation(UCI)from the perspective of SSL.Methods:This study included 25 patients with SSD,11 patients with UCI,and 30 participants with normal hearing(NH).Their SSL ability was tested by obtaining their average root mean square(RMS)error values of SSL test.Results:The results showed that the RMS error value of SSD,UCI and NH groups were 52.26±20.25◦,69.84±12.14◦and 4.27±2.66◦,respectively.The ability of SSL was better in the SSD-L group than that in the SSD-R group,and no significant difference existed in the SSD-R and the UCI group.Conclusion:When bilateral deafness patients select unilateral treatment,right-side cochlear implantation may be more beneficial in terms of SSL,which means that the central auditory cortex in long-term SSD patients is affected differently based on which side their deafness occurs.

Experimental study on failure characteristics of single-sided unloading rock under different intermediate principal stress conditions

Investigation of unloading rock failure under differentσ_(2)facilitates the control mechanism of excavation surrounding rock.This study focused on single-sided unloading tests of granite specimens under true triaxial conditions.The strength and failure characteristics were studied with micro-camera and acoustic emission(AE)monitoring.Furthermore,the choice of test path and the effect ofσ_(2)on fracture of unloading rock were discussed.Results show that the increasedσ_(2)can strengthen the stability of single-sided unloading rock.After unloading,the rock’s free surface underwent five phases,namely,inoculation,particle ejection,buckling rupture,stable failure,and unstable rockburst phases.Moreover,atσ_(2)≤30 MPa,the b value shows the following variation tendency:rising,dropping,significant fluctuation,and dropping,with dispersed damages signal.Atσ_(2)≥40 MPa,the tendency shows:a rise,a decrease,a slight fluctuation,and final drop,with concentrated damages signal.After unloading,AE energy is mainly concentrated in the micro-energy range.With the increasedσ_(2),the micro-energy ratio rises.In contrast,low,medium and large energy ratios drop gradually.The increased tensile fractures and decreased shear fractures indicate that the failure mode of the unloading rock gradually changes from tensile-shear mode to tensile-split one.The fractional dimension of the rock fragments first increases and then decreases with an inflection point at 20 MPa.The distribution of SIF on the planes changes asσ_(2)increases,resulting in strengthening and then weakening of the rock bearing capacity.

Characteristics Investigation of Single-Sided Ironless PMLSM Based on Halbach Array for Medium-Speed Maglev Train

This paper investigates characteristics of ironless permanent magnet linear synchronous motor(PMLSM)based on Halbach array used for medium-speed(200km/h)maglev train.Long primary ironless coil is laid in the middle of track and the Halbach permanent magnet array is attached to the bottom of each bogie as a source of traction,U-shape electromagnets at the both sides of the train for levitation.Two dimensional analytical model of single-sided ironless PMLSM based on Halbach array is established,using linear overlay method,the no-load air gap magnetic field is calculated firstly,winding current density distribution is obtained for calculating the characteristics of thrust and normal force against power angle,including force characteristics with equal and unequal pole pitch,the influence of steel sleeper,etc.Besides,the mathematical model for this type motor is built by 3D finite element method,the traction characteristics of medium-speed maglev under maximum speed 200km/h are calculated.The characteristics of this type motor are satisfactory owing to there is no detent force in the motor and thrust force reach maximum meanwhile normal force can be eliminated.Calculation method is verified by comparing finite element results,experimental result on a 200kW type motor further validates the accuracy of calculation and some important conclusions are obtained.

Adaptive current compensation with nonlinear disturbance observer for single-sided linear induction motor considering dynamic eddy-effect

An adaptive current compensation control for a single-sided linear induction motor(SLIM) with nonlinear disturbance observer was developed. First, to maintain t-axis secondary component flux constant with consideration of the specially dynamic eddy-effect(DEE) of the SLIM, a instantaneously tracing compensation of m-axis current component was analyzed. Second,adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer(NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.

Measurement of thermal conductivity of materials using single-side TPS technique

Based on the traditional measurement theory of transient plane source (TPS) technique, single-side TPS method is proposed for measuring the thermal conductivity of single specimen. The problem of transient heat conduction in a semi-infinite boundary condition is studied and the theoretical formula of single-side TPS method is deduced. During the measurement, the influence of the probe heat capacity on the results is analyzed and the corresponding mathematical compensation model is established, and a series of experiments on different materials are conducted by hot disk probe at normal temperature and pressure. The results show that the relative error with the single-side TPS method is less than 5% and the relative standard deviation is no greater than 3%. This method has high accuracy and good reproducibility, which provides a feasible measuring method for single material that does not meet the requirements of the standard TPS theory.

Experimental Investigation of Defects Inspection for FRP Pipeline based on Single-side NMR

The fiberglass reinforced plastic （FRP） pipelines have been used widely in oil-gas gathering and transportation. The defects of FRP pipelines would increase with the extension of service time. However, it is very difficult to detect the defects of FRP pipelines on-spot quickly. In this paper, a new method detecting defects for FRP pipes has been provided based on the NMR. The proton density distributions have been obtained at different depth of FRP components using single-side NMR. The experimental results show that there is a significant change of proton density distribution at the location of defects. And, these results would be useful for defects inspection of composite material component.

Potential Use of Strain Hardening ECC in Permanent Formwork with Small Scale Flexural Beams

Utilizing pre-cast ECC panels as participating permanent formwork of concrete members, and the validity of using ECC to disperse the single crack in concrete into multiple ones in ECC were studied. In the process, totally two kinds of ECC with different tensile properties, 7 series of flat panels with different top surface figures and 3 U-shape panels with different inner surface forms were investigated. To evaluate the performance of the permanent formworks, small ECC-concrete composite beams were cast and tested mechanically. The 4-point bending test results show that the use of pre-cast ECC panels as permanent formwork can significantly improve the load capacity and toughness of a concrete member, effectively dispersing single widely opened crack in concrete into multiple ones in ECC. Most permanent formworks show perfect bond with the concrete cast on them, while the ones with partially debonded zone achieve the best mechanical performance. The U-shape permanent formworks show better performances than the flat ones, achieving much betler improvements in both the load capacity and toughness, together with better crack width control.

Reinforcement by polyurethane to stiffness of air-supported fabric formwork for concrete shell construction

By spraying concrete on inner surface,air-supported fabric structures can be used as formwork to construct reinforced concrete shell structures.The fabric formwork has the finished form of concrete structure.Large deviation from the desired shape of concrete shells still remains as central problem due to dead weight of concrete and less stiffness of fabric formwork.Polyurethane can be used not only as a bonding layer between fabrics and concrete but also as an additional stiffening layer.However,there is little research on mechanical behaviors of the polyurethane shell structure.This paper presents experimental studies on an inflated fabric model with and without polyurethane,including relief pressure tests,vertical loading tests and horizontal loading tests.Experimental results show that the additional polyurethane layer can significantly enhance the stiffness of the fabric formwork.Compared with the experiment,a numerical model using shell layered finite elements has a good prediction.The reinforcement by polyurethane to improve stiffness of air-supported fabric formwork is expected to be considered in the design and construction of the concrete shell,especially dealing with the advance of shape-control.

Formwork lateral pressure of precast normal-concrete composite shear walls infilled with self-compacting concrete

Wall cracking and mold expanding due to concrete vibrations can be effectively solved through the application of precast normal-concrete composite shear walls infilled with self-compacting concrete(SCC). However, the high liquidity of SCC will induce a higher lateral pressure. Therefore, it is important to obtain a better understanding of the template lateral pressure. In this work, nine composite shear walls were experimentally investigated, focusing on the effects of two parameters, i.e., the casting rate and the section width of the formwork. The time-varying pressure was monitored during the SCC pouring. It is found that the increase of casting rate from 3.2 m/h to 10.3 m/h resulted in a higher maximum lateral pressure. The higher casting rate led to a longer time required for the lateral pressure to drop to a steady value. There was no correlation between the section width and the rate of decrease in the initial formwork pressure and stable value. Based on the test results, a formula considering the effect of casting speed for the calculation of SCC formwork pressure was established to fill the gap in the current standards and for engineering applications.

Interactions between Superplasticizer and Release Agents at the Concrete/Formwork Interface

Improving the knowledge of rheological and tribological characteristics of fresh concrete is important to contribute to the progress of construction sites and the final quality of the work. The objective of this study is to identify the effect of a superplasticizer based on polycarboxylic ether on the tribological behavior of fresh concrete at the concrete/formwork and concrete/oil/formwork interfaces. Friction tests on fresh concrete were carried out using a plan/plan tribometer. In order to study the behavior of the superplasticizer close to the formwork, three concretes with 30% of paste and different dosage of superplasticizer were formulated. The results show that the increase of the dosage of superplasticizer reduces the friction stress. The properties of the superplasticizer generate a deflocculating action of concrete grains and lead to a stabilisation of the soap-oil micellae present in the vicinity of the formwork. Thus, the efficiency of superplasticizer depends on the quantity of fines, on the quantity of soap formed and so, on the release agent formulation.

Cost Comparison of Different Types of Formworks

Formwork is the temporary moulds in the construction which is fabricated based on the drawing and design of the structure and into which the concrete is poured to form the required structure.Formwork is an essential part of the construction as it has been used by the Romans.The formworks must be strong enough to withstand all types of loads.The joint must be in proper condition to avoid any kind of leakages.The materials used for the formworks should be economical,easily available and durable.The formworks can be made up of different materials such as plywood,steel,aluminum,composite material,etc.In steel formwork the plates used for the slab support are made up of galvanized steel and these are fabricated as per the requirements.Aluminum plates are used in the aluminum framework along with the other components made up of aluminum.The selection of a suitable framework is important in any project because it bears about 25%to 30%cost of the total cost of construction.In the present study,different types of formworks such as steel,plywood and aluminum were studied in a project and a comparison was made on the reusability and easiness in handling and maintenance.Also,a comparison of the formwork used in the construction of the 5th and 11th-floor tower based on the specific plan and drawing was done.The results showed that the aluminum formwork was found to be efficient and suitable among all formworks,although the cost was higher compared to other formwork materials.

Discussion Based on Formwork Construction of Box Girder Formwork Design Scheme

Formwork construction has been the important and difficult of the construction process, so the design plan is very important. This paper relies on the Shun Ping Yu subordinate Fertgbo bridge rebuilding project, detailing the cast-in-place box beam formwork support system safety special construction plan, focuses on box girder formwork design scheme of foundation design, box girder bracket design and box girder formwork design, to provide a reasonable reference for similar projects.

THE EVALUATION OF CHANGE IN CONCRETE STRENGTH DUE TO FABRIC FORMWORK

Fabric,as a flexible formwork for concrete,gives builders,engineers,and architects the ability to form virtually any shape.This technique produces a superb concrete surface quality that requires no further touch up or finishing.Woven polyolefin fabrics are recommended for this application.The texture of this fabric allows water from concrete mix to bleed,and therefore reduces the water-cement ratio of the mix.Due to the reduction in the water-cement ratio,a higher compressive strength in fabric-formed concrete is achieved,which is also suggested by earlier studies.The current research study was conducted to investigate and document the changes in concrete strength and overall quality due to these woven polyolefin fabrics.Use of fabric formwork will result in a decrease in construction cost,construction waste,and greenhouse gas emissions.Two sets of tests were conducted in this research study:a comparison of the compressive strength of fabric-formed versus PVC-formed concrete cylinders,and a comparison of the behaviour of the fabric-formed columns versus cardboard-formed reinforced concrete columns.Variables in this research were limited to two types of fabric that included one with coarse and one with a more refined texture,and two types of concrete that included ordinary and flyash concrete.The laboratory results revealed that the effects of fabric formwork on concrete quality in a large member are limited mostly to the surface zone and the core of the concrete remains the same as a conventionally formed concrete.Even though fabric-formed cylinder tests showed an average of a 15%increase in compressive strength of the concrete samples,the compressive strength of the reinforced columns did not dramatically change when compared to the companion cardboard formed control columns.This research confirmed that fabric formwork is a structurally safe alterna-tive for forming reinforced concrete columns.

大跨度混凝土钢筋框架梁挠度超限研究

根据大量的工程实践,大跨度钢筋混凝土框架梁由于设计不合理引起大跨度梁超限的工程案例很少,大多数是施工原因导致挠度超限。以某工程挠度超限的大跨度钢筋混凝土梁为例,根据设计资料和现场检测资料,从设计和施工两方面,利用数值计算和有限元模拟,验证分析大跨度钢筋混凝土框架梁挠度超限的原因。验证分析表明,梁板混凝土实际浇筑厚度超限与梁模板起拱高度不足可能引起梁挠度增加。当梁下立杆稳定承载力不足时,梁也易随立杆屈曲变形产生较大挠度。

拼接成型UHPC免拆模板钢筋混凝土柱的抗震性能

为研究超高性能混凝土(UHPC)免拆模板钢筋混凝土(URC)柱的抗震性能,选取UHPC免拆模板拼接方式和表面处理方式为试验设计参数,制作并完成了9个URC柱和1个钢筋混凝土(RC)柱的拟静力加载试验。模板拼接方式为螺栓加角钢连接、螺栓连接和环氧树脂砂浆连接;表面处理方式为光面处理、气泡膜印花处理和设肋处理,通过拟静力试验研究了模板拼接方式及表面处理方式对该类柱抗震性能的影响。此外,基于平截面假定,提出了URC柱的正截面偏压承载力计算式。结果表明:峰值荷载前,UHPC模板与核心混凝土黏结面无明显破坏,URC柱表现出良好的整体性,尤其是采用螺栓加角钢连接的URC柱,即使加载至极限位移时,也没有发生界面黏结失效破坏;与普通RC柱相比,URC柱的承载力提高了6.4%~43.3%,延性提高了11.4%~48.7%,耗能能力提高了27.7%~85.3%;三种连接方式中,采用螺栓加角钢连接的URC柱承载力最高,连接最可靠。最后,基于平截面假定提出的公式计算值与试验值吻合较好,可为工程应用提供参考。

3D打印混凝土永久模板叠合柱的抗压性能数值模拟研究

为深入研究3D打印混凝土永久模板叠合柱的抗压性能,基于3D打印混凝土永久模板叠合柱及同尺寸整体现浇对照柱试验建立构件数值模型,模拟分析其轴压荷载-位移响应及失效形态。针对界面粘结性能、现浇混凝土抗压强度、打印模板厚度、荷载偏心距等参数开展3D打印混凝土永久模板叠合柱的抗压性能计算分析,研究表明:叠合柱轴压极限承载力随着薄弱界面剪切强度、刚度及现浇混凝土抗压强度的增大而增大。由于打印材料的抗压强度高于现浇混凝土,叠合柱抗压极限承载力提升率与打印模板厚度呈近似线性关系,叠合圆柱的抗压极限承载力随着荷载偏心距的增大而降低,呈近似线性负相关。此外,偏心距对叠合圆柱极限承载力下降幅度的影响大于现浇圆柱。

Application of Mobile Formwork Cast-In-Situ Beam Technology in Bridge Construction

The application of mobile formwork cast-in-situ beam technology is conducive to providing quality assurance for bridge constructions.At the same time,it can improve the overall mechanization level of the construction process and further accelerate the construction progress,so as to shorten the construction period and improve the economic benefits of enterprises.In fact,this construction method has been widely applied.In order to assure a positive outcome from the use of this technology,this paper analyzes the application of mobile formwork cast-in-situ beam technology in bridge construction to provide reference.

织物增强混凝土永久模板叠合试件抗氯离子渗透性能研究

织物增强混凝土(TRC)由高性能细骨料混凝土基体与纤维网组成,TRC永久模板与核心混凝土组成叠合试件。为揭示叠合试件氯离子渗透作用规律,确定永久模板最佳厚度范围,以TRC永久厚度、耐碱纤维网层数以及界面处理方式为变量,进行叠合试件抗氯离子渗透性能试验研究和计算分析。结果表明:与未设置永久模板相比,当TRC永久模板厚度为10~50 mm时,叠合试件氯离子扩散系数分别降低73.2%~95.6%。耐碱纤维编网对永久模板抗氯离子渗透性能没有增强作用。水泥净浆涂刷、表面凿毛、短切纤维插入三种界面处理方式对叠合试件氯离子渗透系数和渗透深度的影响不显著。结合Duracrete模型定量分析,给出了海洋环境不同工况下TRC永久模板厚度建议范围。

基于铝模板BIM自动配模需求的结构模型研究

针对现有铝模板自动配模效率低和准确性差的问题,主要由BIM结构模型信息量大、建模规范性差及配模规则约束不清晰等因素造成。本文以铝模板配模设计阶段中的结构模型为研究重点,首先分析了模型中有效的空间信息与构件信息,然后在模型建模、分类编码以及避让策略方面制定了相应规则。通过选取工程案例并开发测试插件以实现信息提取与自动配模,验证了模型信息的有效性和规则的可行性。研究结果表明,所提方法不仅能显著提高铝模板BIM自动配模的效率,还能为其他BIM结构模型的相关研究提供借鉴和支持。

基于拉丁超立方抽样的高大模板支撑体系承载力有限元分析

目的研究不同缺陷构配件下高大模板支撑体系承载性能的变化,为高大模板支撑体系的布置、构配件的搭配及使用提供指导,以预防和减少其在实际工程中的坍塌事故。方法基于拉丁超立方抽样,考虑构配件缺陷对三种搭设参数模板支撑体系承载性能的影响,随机取线性屈曲分析中一阶屈曲承载力的0.1%~0.2%作为假想水平力,对构配件性能缺陷进行有限元分析,探究不同搭设参数下支撑体系承载力及失稳模式。结果SPR对承载力的影响大于D和t,并且双因素耦合对承载力的影响大于单因素。立杆步距的变化对支撑体系承载力的影响大于立杆间距。随着影响因素耦合数量的增加,步距对支撑体系承载性能的影响也会随之增大。结论支撑体系搭设过程中将存在缺陷的构配件使用时分散排布,可以防止高大模板支撑体系整体失稳倒塌。