Linear-Range Extension for Linear Variable Differential Transformer Using Hyperbolic Sine Function.

Linear variable differential transformer (LVDT) is widely used to measure the small displacements. It has many advantages over other displacement measuring transducers like potentiometer. This paper explores the characteristics of temperature dependency of LVDT. At higher temperature the output of the LVDT is generally altered. By suitable selection of the stable permeable material for the core of LVDT, the temperature dependency of the LVDT output can be minimized. The effect of temperature on the permeability of the core of LVDT and output is studied in this work using the COMSOL Multiphysics software.

Meminductor is a nonlinear two-terminal element with storage energy and memory ability. To date, meminductor element is not available commercially as memristor and memcapacitor are. Therefore, it is of great significance to implement a meminductor emulator for breadboard experiment. In this paper, a flux-controlled floating/grounded meminductor emulator without a memristor is presented. It is built with commercially available off-the-shelf electronic devices. It consists of single operational transconductance amplifier (OTA), single multiplier, two second-generation current conveyors (CCIIs), single current-feedback operational amplifier (CFOA) and single operational amplifier. Using OTA device introduces an additional control parameter besides frequency and amplitude values of applied voltage to control the area of pinched hysteresis loop of meminductor. Mathematical model of proposed emulator circuit is given to describe the behavior of meminductor circuit. The breadboard experiment is performed using CA3080, AD844, AD633J and LM741 for OTA, CCII–CFOA, multiplier and operational amplifier, respectively. Simulation and experimental test results are given to verify the theoretical analyses. Frequency-dependent pinched hysteresis loop is maintained up to 5 kHz. The presented meminductor emulator tends to work as ordinary inductor for higher frequencies.

The voltage feedback operational amplifier (VFOA) and the current feedback operational amplifier (CFOA) are the main voltage type output opamps currently used in electronics. The VFOA is a combination of an operational transconductance amplifier (OTA) used as an input stage and an output voltage buffer (VB). In this paper, the CFOA is described as a combination of an operational transconductance conveyor (OTC) used as an input stage and with an output voltage buffer. Two similar CMOS architectures are then defined, analysed and simulated in order to provide some elements of comparison. Results, from a typical CMOS 0.35μm transistor parameters, show the role of compensation capacitances in boosting the frequency performances of the non-inverting amplifier.

Different types of materials are being considered for fuel, cladding, and structures in existing and advanced nuclear reactors. These materials can undergo significant dimensional changes during irradiation. Currently in the US, such changes are measured with the ‘cook and look’ method (i.e. repeatedly irradiating a specimen for a specified period of time, and then removing it from the reactor for evaluation) – which leads to costly and time consuming experiments. In addition, such techniques provide limited data, and handling may disturb the phenomena of interest. Therefore, in-pile detection of geometric changes is needed to understand real-time behavior during irradiation testing of fuels and materials in high flux US Material and Test Reactors (MTRs). The developmental results of an advanced Linear Variable Differential Transformer (LVDT)-based test rig capable of detecting real-time changes in diameter or length of fuel rods or other material samples during irradiation in US MTRs are presented. The LVDT is being developed at the Idaho National Laboratory (INL), and will provide experimenters with the capability to measure dimensional changes associated with fuel and clad swelling, pellet-clad interaction, and crud buildup. The LVDT design utilizes the MTR’s loop pressure to drive the test specimen at a constant rate. This leads to a simplified construction which only requires three pressure boundary penetrations. Further, the LVDT pressure boundary is a leak tight hydraulic ram capable of actuating under low differential pressure (e.g. 1 psid), and is able to survive the high irradiation tests at Pressurized Water Reactor (PWR) conditions.

A novel signal conditioning system for linear variable differential transformers (LVDTs) is presented. This system considers the signals involved in the operation of the LVDT to be analogous to a double sideband suppressed carrier AM (DSBSC-AM) communication system, where the position information is akin to the signal to be transmitted and the input sine wave elicitation to the LVDT is akin to the carrier wave. Signal conditioning is achieved through a modified digital signal processor-based Costas receiver. This system has better dynamic response than existing solutions and better noise rejection than commercially available solutions. Static testing of the system using both 4-wire and 5-wire LVDTs verifies that the conditioner meets or exceeds the linearity performance of existing signal conditioning systems over the full-scale operating range. In addition, this system requires no phase compensation network or manual tuning.

A novel signal conditioning system for Linear Variable Differential Transformers (LVDT) is presented. This system considers the signals involved in the operation of the LVDT to be analogous to a Double Sideband Suppressed Carrier AM (DSBSC-AM) communication system, where the position information is akin to the signal to be transmitted and the input sine wave excitation to the LVDT is akin to the carrier wave. Signal conditioning is achieved through a modified digital signal processor-based Costas receiver. This system has better dynamic response than existing solutions and better noise rejection than commercially available solutions. Static testing of the system using both 4-wire and 5-wire LVDTs verifies that the conditioner meets or exceeds the linearity performance of existing signal conditioning systems over the full-scale operating range. In addition, this system requires no phase compensation network or manual tuning.

Full-field measurement of micromotion around a cementless femoral stem using micro-CT imaging and radiopaque markers

This project presents the development of patellar reflex measurement system using Linear Variable Differential Transformer (LVDT). The measurement system is based on knee reflection as the patellar tendon was tapped with tendon hammer. The system proposed capable to detect four graded levels of Deep Tendon Reflex (DTR) which are zero absent, hypoactive (underactive), normal, and hyperactive (overactive). The LVDT sensor use to convert the mechanical displacement of leg reflection into voltage signal. The signal will go through Data Acquisition Card (DAQ) and displayed by personal computer (PC). LabVIEW 8.0 software will analyze the voltage signal and the patellar reflex will be graded based on the peak voltage signal. The data can be saved in Microsoft Excel file (*.xls) for record and references. The measurement system has been test on 20 respondents for validation purpose. The development system is user friendly and able to assist neurologist to analyze and graded level of the patellar reflex measurement.

Role of Impaired Lower-Limb Venous Innervation in the Pathogenesis of the Chronic Fatigue Syndrome

Synthesis of active inductors using SFG stamps

ABSTRACTA compact linear variable differential transformer (LVDT) is newly designed, fabricated, and tested for its possible use in the in-reactor experiments, due to the restricted space available in reactors for experiments. This paper discusses the approach adopted in obtaining analytical equations for designing the LVDT and verifying of the result using experiment and by computation using COMSOL software. In the analytical work, an integral equation is derived using equations for current carrying conductor between the primary and secondary coils. It is then solved by applying three-dimensional coordinate geometry using MATLAB. Results obtained from solving analytical equations, COSMOL computations and experiment are seen to be matching with each other.

An innovative magnetic module which is concurrently capable of performing as an actuator and a sensor is proposed and illustrated. The magnetic module is basically similar to a micro-scale Linear Variable Differential Transformer (LVDT) which is employed to actively adjust the height of a rotating seismic disc used in a gyroscope so that the induced pitch angle by Coriolis effect, purely due to exerted angular excitation, can be accurately measured. That is, the micro-magnetic module acts like an actuator for height regulation on the seismic proof mass by applying appropriate electric current to the primary coil of the LVDT. On the other hand, the secondary coil pair of the LVDT acts as a sensor which can detect the gap change between the seismic rotating disc doped by magnetic material and the micro-magnetic module and the rotation speed (i.e., frequency) by measurement of the peaks of sine wave of induced electric current.

The current-feedback operational amplifier (CFA) is an active device which uses the supply-current sensing technique in order to achieve high performance features for analog signal processing applications. However, under certain load conditions, the CFA exhibits an unstable behavior. This work presents a new frequency model which rakes into account the non-unilateral characteristics of the CFA buffer stages and includes the load-dependent instabilities. The model can be easily incorporated into a standard macromodel for simulation purposes or used analytically for accurate circuit design based on CFAs. As a consequence of this approach, some improvements in the CFA structure could be suggested.

This paper investigates some fundamental properties of hyperbolic trigonometric functions on the hyperbolic number plane. Hyperbolic numbers form a commutative ring with zero divisors, generated by two real numbers via the Cartesian basis. Within this algebraic framework, this paper systematically establish the system of hyperbolic trigonometric functions. By fully leveraging the decomposition properties of hyperbolic numbers and their associated trigonometric functions, this work effectively overcomes the mathematical difficulties arising from the presence of zero divisors in the hyperbolic number ring. On this basis, this paper for the first time in the context of a hyperbolic number ring containing zero divisors, systematically derived and rigorously proved the addition theorems for the hyperbolic sine, cosine, tangent, and cotangent functions. On this basis, we have successfully derived and rigorously proved the addition theorems for the hyperbolic sine, cosine, tangent, and cotangent functions, establishing a complete system of angle addition formulas and laying a solid foundation for the theory of hyperbolic functions. The addition theorems established in this research will provide an important theoretical foundation for the further development of hyperbolic analysis in function theory, while simultaneously injecting new research momentum into the further study of the properties and expansions of hyperbolic trigonometric series. These theoretical achievements are expected to play significant roles in the study of hyperbolic differential equations, geometric analysis, and related physical problems.

Forex indicators are one way of examining market data. One of the best methods is using approximations of quadratic curves. For example, the Parabolic SAR indicator is an indicator that approximates the trend by a parabola. Of course, not all indicators necessarily map the direction of the trading trend with a curve. But discovering a clear curved path for the trading trend is definitely the dream of many great analysts. The problem that we are dealing with here is actually trying to generalize the idea of approximating the direction of the trading process by using hyperbolic functions. Suppose there are two fixed points in the movement of the financial market and the path length between these two points is also a fixed number, using numerical approximation methods, we try to calculate the maximum and minimum amount of financial market movement. The main idea that is in our minds is the approximation of financial market trends by using hyperbolic functions. We approximate the path between these two points with a hyperbolic sine function. Finally, we try to find the maximum or minimum points of this hyperbolic sine function numerically.