A model for the Barkhausen frequency spectrum as a function of applied stress

We derive a two parameter multi-exponential model to describe the frequency spectrum ofBarkhausen noise in bulk steel under high excitation rates and applied tensile stress. We show how the amplitude and shape of the frequency spectrum depend on two directly measurable quantities, Barkhausen voltage and effective magnetic permeability, respectively, and how these change with stress. By incorporating frequency and depth dependence components into our model, we provide a framework for identifying stress variations along depth, which can be used for the purposes of non-destructive characterization

Optimization of sensor design for Barkhausen noise measurement using finite element analysis

The effects of design parameters for optimizing the performance of sensors for magneticBarkhausen emission measurement are presented. This study was performed using finite element analysis. The design parameters investigated include core material, core-tip curvature, core length, and pole spacing. Considering a combination of permeability and saturation magnetization, iron was selected as the core material among other materials investigated. Although a flat core-tip would result in higher magnetic flux concentration in the test specimen, a curved core-tip is preferred. The sensor-to-specimen coupling is thereby improved especially for materials with different surface geometries. Smaller pole spacing resulted in higher flux concentration

A Hydraulic Evapotranspiration Multisensor

An exclusively mechanical stand-alone automatic device, self-adjusting to weather changes for controlled irrigation, that operates only on the energy of piped water, without electricity, is the described low-cost “Hydraulic Evapotranspiration Multisensor-HEM”. It is composed of an Evaporation Pan with water left to evaporate, a Floater with a Magnet floating in this water, a Hydraulic Device managing a Hydraulic Water Valve having means to adjust irrigation frequency, and a system that returns water to said Pan, through an Adjustable Dripper, to replace that lost by evaporation. During the Evaporation Phase, gradually the water level is lowered to a predetermined level, at which the floating Magnet acts on said Hydraulic Device to start irrigation. Water from the irrigation line is returned to the Evaporation Pan at the proper for the irrigation time rate. When the lost water is replaced irrigation is terminated and the system resets. On installation Irrigation Frequency and Irrigation Time are set with two graduated screws, for normal weather and the conditions of the particular plantation. HEM responding to weather changes modifies the irrigation schedule set, either by shortening, at a high evaporation rate, the time interval between consecutive irrigation cycles to protect plantations from water deficit stress or extending this time interval at a low evaporation rate to save water. Assessing the performance of HEM, by taking the estimations of evapotranspiration from the Penman–Monteith method shows high accuracy in the studied site. Considering the advantages of the product against the programmable irrigation controller devices, HEM provides optimum irrigation control in field crops and makes it a powerful “green tool” to be used in Mediterranean greenhouses. © 2022 by the authors

2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk (vol 290, pg 140, 2019)

Cardiolog

2019 ESC/EAS guidelines for the management of dyslipidaemias: Lipid modification to reduce cardiovascular risk

Cardiolog