Redefining speakership: Implications for language program direction

This article reviews scholarship in sociolinguistics and applied linguistics to discern how the definitions of speakership and competence have changed in the last fifty years. It is shown that the redefined concepts reflect a new understanding of language that is no longer consonant with many current teaching practices anchored in structuralism and monolingualism. Next, the article outlines five tenets of language based on Blommaert’s (2010) critical sociolinguistics of globalization and discusses the implications of these tenets for language program direction

Highly sensitive smart flow sensor with frequency and duty cycle output

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Low-frequency RFID signal and power transfer circuitry for capacitive and resistive mixed sensor array

This paper presents a contactless measurement system for a mixed array of resistive and capacitive sensors exploiting a low-frequency radio-frequency identification (RFID)-based approach. The system is composed of a reader unit which provides power to and exchanges measurement data with a battery-less sensor unit. The sensor unit is based on a transponder operating at 134.2 kHz and a microcontroller. The microcontroller sequentially measures the elements of the sensor array composed of n capacitive and m resistive sensors which share a common terminal. The adopted technique measures the charging time of a resistor-capacitor (RC) circuit, where the resistor or the capacitor can be either the sensing element or a reference component. With the proposed approach, the measured values of the resistive or capacitive elements of the sensor array are first-order independent from the supply voltage level. A prototype has been developed and experimentally tested with resistive elements in the range 400 kΩ-1.2 MΩ and capacitive elements in the range 200 pF-1.2 nF showing measurement resolution values of 1 kΩ and 5 pF, respectively. Operative distances up to 3 cm have been achieved, with readings taken faster than one element of the array per second

Characterization of thermoelectric modules for powering autonomous sensors

The characterization of three commercial thermoelectric modules, which are designed for cooling/heating applications, is presented to employ the devices for power conversion, i.e., as thermoelectric generators (TEGs). The thermoelectric theory is briefly summarized at first, taking into account the relationship between the effective temperature difference across the TEG junctions and the temperature difference applied externally, considering insulating ceramic plates having finite thermal conductance. The thermoelectric modules have been characterized in terms of open-circuit output voltage and output power density for different temperature gradients and load conditions. Measurement techniques and experimental data are reported, which show the possibility of using thermoelectric devices for energy-harvesting applications. A comparison of the results from the tested devices with the performance data of commercial TEGs that are specifically designed for power harvesting is then presented, and the main characteristics of the two device typologies are discussed. A TEG was then used to supply an autonomous system that interfaces with a temperature sensor and periodically transmits the measurement information via an RF link. Experimental data show that the system works correctly and sends the RF signal when the temperature difference that is applied across the TEG is higher than 34 K