scholarly journals Guided Wave Transducer for the Locating Defect of the Steel Pipe Based on the Weidemann Effect

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 333
Author(s):  
Jin Xu ◽  
Guang Chen ◽  
Jiang Xu ◽  
Qing Zhang
Keyword(s):  
Energy Conversion ◽  
Structural Parameters ◽  
Basic Structure ◽  
Guided Wave ◽  
Steel Pipe ◽  
Basic Functions ◽  
Wave Transducer

The electromagnetic guided wave transducer has been widely used in pipeline detection in recent years due to its non-contact energy conversion characteristics. Based on the Weidemann effect, an electromagnetic guided wave transducer that can realize the locating defect of the steel pipe was provided. Firstly, the principle of the transducer was analyzed based on the Weidemann effect. The basic structure of the transducer and the basic functions of each part were given. Secondly, the key structural parameters of the transducer were studied. Based on the size of the magnets and the coils, a protype electromagnetic guided wave transducer based on Wiedemann effect was developed. Finally, the experiments were carried out on the steel pipe with a defect using the developed transducer. The results show that the transducer can actuate and receive the T(0,1) and T(1,1) modes in the steel pipe. The axial positioning of the defect is located by moving the transducer axially. The circumferential positioning of the defect is located by rotating the transducer. Additionally, missed detection can be effectively avoided by rotating the transducer.

Teaching the form-function mapping of German ‘prefield’ elements using Concept-Based Instruction

2016 ◽  
Vol 4 (1) ◽  
pp. 153-170
Author(s):  
Ingo Fehrmann
Keyword(s):  
Second Language Acquisition ◽  
Foreign Language ◽  
Information Structure ◽  
Language Production ◽  
Basic Structure ◽  
Form Function ◽  
Basic Functions ◽  
Beginning Learners ◽  
Based Instruction ◽  
Function Mapping

Abstract Empirical findings in Second Language Acquisition suggest that the basic structure of German declarative sentences, described in terms of topological fields, poses certain challenges to learners of German as a foreign language. The problem of multiple prefield elements, resulting in ungrammatical verb-third sentences, figures most prominently in the literature. While the so-called V2 constraint is usually treated as a purely formal feature of German syntax both in the empirical as well as in the pedagogical literature, the present paper adopts a usage-based perspective, viewing language as an inventory of form-function mappings. Basic functions of prefield elements have already been identified in research on textual grammar and information structure. This paper presents results from a pilot study with Japanese elementary learners of German as a foreign language, where the form-function mapping of German prefield elements was explicitly taught following the guidelines of an approach called Concept-Based Instruction. The findings indicate that, with a focus on the function-function mapping, it is in fact possible to explicitly teach these rather abstract regularities of German to beginning learners. The participants’ language production exhibits a prefield variation pattern similar to that of L1 German speakers; at the same time the learners produce very few ungrammatical verb-third sentences.

Enhancing pressure comfort of a bra’s under-band

2017 ◽  
Vol 88 (19) ◽  
pp. 2250-2257 ◽  
Author(s):  
Chi Liu ◽  
Feng-Xiang Miao ◽  
Xiao-Ying Dong ◽  
Bugao Xu
Keyword(s):  
Female Body ◽  
Pressure Range ◽  
Structural Parameters ◽  
Basic Structure ◽  
Direct Impact ◽  
Tension Tests ◽  
Objective Tests ◽  
Subjective Fit

The under-band of a bra with line-shaped wings (“− −”) covers the underbust girth of a female body and determines the size of bra. The wearing pressure of an under-band has a direct impact on a bra’s comfort. In this article we used both subjective fit assessments and objective tension tests on bras of the same size and the same basic structure to explore the relationships between the structural parameters and the wearing pressures of under-bands, and to establish the equation for under-band length adjustment that enhances the pressure comfort and fit level. In the fit test, 100 bras of size 75B (US 34B)manufactured by one company were randomly selected, and classified by five professional models into five fit levels: tight, slightly tight, fit, slightly loose and loose. In the objective tests, the key structural parameters, i.e. the natural dimensions of under-band lengths and widths, of these samples were first measured, and then the tensions of the under-bands were tested on a tensile machine where the under-bands were stretched to the bras’ design size. Based on the bras’ equivalent pressure, the equation to predict the wearing pressure of the under-band was built on the structural parameters and the tension data. Using the “fit” bras identified in the fit test, a comfortable pressure range was established for bra comfortability assessment. Based on a comfortable pressure, the length of an under-band could be adjusted to keep its fit level as “fit” when the initial wearing pressure did not fall into the fit range.

Force Analyzing and Parameter Optimization of the Telescopic In-Pipe Robot

2015 ◽  
Vol 738-739 ◽  
pp. 941-945
Author(s):  
Di Qu ◽  
Hua Song ◽  
Jing Sun
Keyword(s):  
Structural Parameters ◽  
Small Diameter ◽  
Optimal Solution ◽  
Basic Structure ◽  
Optimization Method ◽  
Multi Objective Optimization ◽  
Trenchless Technology ◽  
Motor Torque ◽  
Underground Pipelines ◽  
Locking Mechanism

Typical wheeled or tracked robot could hardly apply to middle or small diameter underground pipelines laid by trenchless technology. Aiming at this kind of pipeline’s characteristics, this paper puts forward a basic structure of telescopic in-pipe robot. To provide necessary theoretical basis for the device selection, the mechanical model and force analyzing are given in detail. The speed of robot, as well as the motor torque of locking mechanism, could be expressed as the function of the robot’s structural parameters. As a result, the robot’s structural parameters take influence on its performance. In order to achieve the best performance, it is necessary to use the multi-objective optimization method to select these parameters. Using the genetic algorithm toolbox, the optimal solution of these parameters was obtained. Based on this, the motor torque of locking mechanism is minimum while the speed of the robot is maximum.

The Simulation of Heat and Vapour Transfer Trough Fibrous Materials

2010 ◽  
Vol 297-301 ◽  
pp. 1205-1209 ◽  
Author(s):  
Ivana Salopek Čubrić ◽  
Zenun Skenderi
Keyword(s):  
Structural Parameters ◽  
Basic Structure ◽  
Raw Material ◽  
Fibrous Materials ◽  
Vapour Permeability ◽  
Physiological Processes ◽  
Repeat Units ◽  
Materials Used

The heat and water vapour transmitting properties of fibrous materials are important factors that affect the clothing's comfort as well as the quality of special functional clothing that is worn in extreme environmental conditions. The paper introduces advanced system for the simulation of physiological processes that appear next to the human skin. Its use enables the measurement of heat and vapour transfer trough fibrous structures, as well as determination of vapour permeability and permeability index. The experiments reported here refer to the measurement of a number of fibrous materials used for the next-to-skin wear. For the measurement have been produced materials that differ either in their structure or raw material in order to observe the influences of different parameters to the transfer properties. The transfer trough fibrous materials is mainly affected by its structure that comprises of a repeat units with cellular geometry containing air pores, yarns that form basic structure and intersection points of two or more yarns. Therefore, the structure of materials is also investigated and described by means of fabric moduli. Dynamics of heat and vapour transfer is observed through the experimentally obtained data and the influence of a number of structural parameters is discussed. The statistical methods are used to qualify the effects of investigated variables on the heat and vapour resistance.

scholarly journals Flow Estimation in a Steel Pipe Using Guided Waves

2016 ◽  
Vol 713 ◽  
pp. 329-333
Author(s):  
John Quiroga ◽  
Jabid Quiroga ◽  
Luis Mujica ◽  
Rodolfo Villamizar ◽  
Magda Ruiz
Keyword(s):  
Flow Rate ◽  
Guided Waves ◽  
Wave Pattern ◽  
Guided Wave ◽  
Laminar Flows ◽  
Steel Pipe ◽  
Needle Valve ◽  
Longitudinal Waves ◽  
Flow Energy ◽  
Flow Rate Increase

In this investigation, a flow rate estimation guided wave based scheme in pipes is proposed. The effect of the fluid over the propagation of longitudinal waves has been experimentally studied by using several laminar flows of water transported by a steel pipe. Results have shown a decrease of the guided wave pattern repeatability and the signal energy as the flow rate increase as a result of the energy leakage from the pipe to the fluid. A Matlab® script is used to excite the PZT actuator via picoscope 2208 of Picotech®, the captured signal is acquired also by the picoscope and the data is processed in Matlab. The test bench utilized is composed by a 1” sch 40 A-106 pipe, a needle valve and a centrifugal pump provides the flow energy. A couple of PZTs are used in a picth-catch configuration to produce and capture the longitudinal waves along the cross section of the pipe

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