Drop-On-Demand Lubrication of Gears: A Feasibility Study

Different lubrication methods such as oil dip or injection lubrication are used in gearboxes to lubricate tribological contacts and to dissipate frictional heat. To improve resource and energy efficiency, novel needs-based lubrication methods like the drop-on-demand lubrication are being developed. It includes an ink-jet nozzle driven by a piezo element to generate picoliter droplets injected to tribological contacts. This study evaluates the feasibility of drop-on-demand lubrication of gears. Friction measurements in rolling-sliding contacts indicate the formation of typical elastohydrodynamic contacts. Power loss measurements of gears show a similar behavior compared to continuous minimum quantity lubrication. Hence, the study confirms that the operation of gears with drop-on-demand lubrication is possible. It introduces the possibility of dynamic and flexible oil supply on a contact needs-based level.

Modeling of Piezoceramic Actuators for Control

In this chapter a full electromechanical model of piezoceramic actuators is presented. This model allows for easy integration of the piezo stack with a structural finite element model (FEM) and includes the flow of energy into and out of the piezo element, which is governed by the transducer constant of the piezo element. Modeling of the piezo stack capacitive hysteresis is achieved using backlash basis functions. The piezo model can also be used to predict the current usage of the PZT which depends on the slew rate of the voltage applied to the PZT. Data from laboratory experiments using a load frame and free response tests is used to estimate the PZT model parameters. In addition, a simplified model of a modulated full bridge strain gauge is derived based on test data which includes the effect of intrinsic bridge imbalance. Sensors of this type are often used with feedback control to linearize the behavior of the device. Taken together, the actuator and sensor model can be used for the development of piezo actuated control algorithms.

An Open Source Classifier for Bed Mattress Signal in Infant Sleep Monitoring

ObjectiveTo develop a non-invasive and clinically practical method for a long-term monitoring of infant sleep cycling in the intensive care unit.MethodsForty three infant polysomnography recordings were performed at 1–18 weeks of age, including a piezo element bed mattress sensor to record respiratory and gross-body movements. The hypnogram scored from polysomnography signals was used as the ground truth in training sleep classifiers based on 20,022 epochs of movement and/or electrocardiography signals. Three classifier designs were evaluated in the detection of deep sleep (N3 state): support vector machine (SVM), Long Short-Term Memory neural network, and convolutional neural network (CNN).ResultsDeep sleep was accurately identified from other states with all classifier variants. The SVM classifier based on a combination of movement and electrocardiography features had the highest performance (AUC 97.6%). A SVM classifier based on only movement features had comparable accuracy (AUC 95.0%). The feature-independent CNN resulted in roughly comparable accuracy (AUC 93.3%).ConclusionAutomated non-invasive tracking of sleep state cycling is technically feasible using measurements from a piezo element situated under a bed mattress.SignificanceAn open source infant deep sleep detector of this kind allows quantitative, continuous bedside assessment of infant’s sleep cycling.

Модифицированные параметры приема 1-3-композитов на основе сегнетоэлектрических кристаллов

A system of modified figures of merit is studied for fibrous piezo-active composites ‘system of aligned ferroelectric crystal rods – polymer matrix’ with 1–3 connectivity in a wide volume-fraction range of the crystal component. The modified figures of merit are important to estimate an effectiveness of harvesting, accumulating and transducing energy in a piezo-element at a constant mechanical stress or constant strain. Polydomain [001]-poled (1 – x)Pb(Mg1/3Nb2/3)O3 – xPbTiO3 (0.28  x  0.33) and [Liv(K1-yNay)1-v](Nb1-zTaz)O3:Mn (v = 0.06, y = 0.1 … 0.3, z = 0.07 … 0.17) crystals serve as piezoelectric components. Comparison of parameters evaluated for the 1–3 composites by means of the matrix method and effective field method is made. Analysed is the role of electromechanical properties of the crystal component in forming the modified figures of merit of the composite. Based on results on modeling the effective properties and related modified figures of merit, advantages of the lead-free 1–3 composite over its analogs based on (1 – x)Pb(Mg1/3Nb2/3)O3 – xPbTiO3 crystals are shown.

A Waveguide Ultrasonic Phased Array Radar for High Temperature Equipment Monitoring

This paper proposes a design for monitoring high temperature structures utilizing phased array waveguide transducers, where the active sensing elements work synthetically together to achieve damage detection. The waveguide transducer is comprised of a wave-generation piezo element and a waveguide bar conducting the wave energy into the host structure. A coupled-field local finite element model (FEM) is constructed to grasp an in-depth understanding of the wave generation behavior. Via the harmonic analysis, optimum wave generation frequency and mode type can be analyzed. Thereafter, an array of waveguide transducer elements are attached to the host structure to study their wave manipulating ability. The system works based on the principle of phased array theory; the excitation instant of each element is controlled to form an equiphasic surface. In this way, the wave propagation phenomenon such as focusing and directional steering can be realized. An ultrasonic radar for high temperature working condition can thus be realized. The proposed system possesses great application potential to enhance the performance of Lamb wave SHM and NDE systems for high temperature structures.

Advance in a meteorological station, developed in educational environment, for agricultural and urban purposes

<p>Internet of Things (IoT) has revolutionized many fields in every-day life. It addresses many aspects related to data management, storage and connectivity.</p><p>The main objective of this project focuses on the application of IoT to a low-cost system to be used on land for monitoring plant life parameters (humidity, temperature, rain, solar radiation, etc.) in crop growing control, viticulture, pest prevention for olive groves, greenhouse automation and other applications in agriculture.</p><p>Additional applications are in urban environment (where major problems of extreme weather phenomena occur) and in the integration with existing trust networks for better characterization of weather phenomena on very limited space and time scales. Adaptation strategies must start from the knowledge and the availability of additional information.</p><p>In a previous project (EGU2018), an ArduinoUno-based control system board was utilized. The fully automatic equipment allowed transmission of real-time data using external esp8266 Wi-Fi.</p><p>In the new version, a LoLiN board, an Arduino board-compatible with integrated ESP8266 and RTC with a few Lua script lines, is used. The board allows a simplification of the design-and-development phase, and an overall reduction of costs.</p><p>The proposed system uses wireless sensors placed in open space and collects information stored on cloud server. The diffusion of a large number of sensors is possible through the use of low-cost sensors and technologies. The new target for this project is to develop a microcontroller system on Wi-Fi protocol based on ESP8266 connected in station mode for data collection, and on LoRa protocol for interconnection among multiple systems that cannot be connected with Wi-Fi.</p><p>The system has been fully developed in the University of Florence, and a high school under the supervision of teachers, involving potential stakeholders interested in the use of low-cost sensors in agriculture. Some traditional sensors, tipping bucket raingauges, magnetic reed devices anemometers, capacitive/resistive thermos-hygrometers, and an innovative impact piezo-element raingauge have been adapted in order to develop the meteorological station.</p><p>During the current year 2020, the LoRa protocol will be developed on the new system to interconnect multiple systems in the absence of Wi-Fi coverage.</p><p>Despite the low nominal cost of data collection, the current use for application in precision and smart agriculture, as well as in climate change monitoring and adaptation, could be possible only through a massive work of sensor calibration in order to reach the standards of the WMO. In any case, also in absence of absolute calibration the quantification of measurement uncertainties is mandatory to give value to the amateur network observations.</p><p>All these aspects are included in the presented project, an attempt to develop a low-cost weather monitoring system for educational purposes, but with lateral effects of awareness among students.</p>

Simulation of contact interaction of piezoelectric engine elements

In the article the results of a new type of piezo-electric step-engine research are presented. The original construct of piezo-electric step-engine is contained in special engineering lever called grab device that can organize back and forward rod’s motion with only one piezo element activity. To choose the effective process of piezo-electric step-engine work the mathematical model was created. This mathematical model describes inner piezo-electric step-engine process with features of contact and electroelastic deformation. Using the ANSYS application package, а finite element model of the piezo-electric step-engine has been developed. This finite element model allows estimate the stress-strain state of structural elements of the piezo-electric step-engine and determine the effective step-by-step operation mode of the piezo-electric step-engine. Using the finite element model, the influence of the piezo-electric step-engine operating mode parameters on the amount of displacement of the rod is studied. According to results of experimental studies, the proposed numerical model allows to simulate the dynamic process of step-operation of a piezo-electric step-engine with an error of no more than 6 %. This finite element model include the external load on piezo-electric step-engine and can be used to design piezo-electric step-engine of various fields of application.

Mathematical modeling of piezoelectric step-engine work

In the article the results of new piezoelectric step-engine research are presented. The original construct of piezoelectric step-engine is contained in special engineering lever called grab device that can organize back and forward rod’s motion with only one piezo element activity. To choose the effective process of piezoelectric step-engine work the mathematical model was created. This mathematical model describes inner piezoelectric step-engine process like a non-linear vibrational system. The mathematical model identifies speed of piezoelectric step-engine elements over the vibration period with different frequency, load level and voltage. The prototype of piezoelectric step-engine was produced. Experimental issues were conducted. Piezoelectric step-engine’s technical specifications are positioning accuracy over 10–6 meter, speed of movement over 10 mm per minute with weight of load to 1 kg and voltage to 100 Volt. On the results of experimental research it is defined that mathematical model enables to model working process of piezoelectric stepengine with an error not more than 10 %. This research verifies viability of proposed construction and provides the way to increase output power of piezoelectric step-engine.

Experimental sea wave energy extractor based on piezoelectric Ericsson cycles

Recycling ambient energies with electric generators instead of employing batteries with limited lifespans has motivated a large scientist community over two decades. Sea waves exhibit a large energy density. The amount of energy that could be extracted from the sea waves is very high. This work describes a technique of sea wave energy extraction based on a piezoelectric conversion and an analogy with thermodynamic Ericsson loops. By synchronizing external electric field to the maximum and the minimum of the sea wave mechanical stress excitations, the piezoelectric material dielectric hysteresis loop area is increased corresponding to the maximum of the energy available. In this article, technical solutions are proposed for the in site deployment of the proposed technique (maximum and minimum detection, external electric field source synchronization). Experimental measuring benches have been developed to monitor the sea wave mechanical excitation and to determine precisely the energy-harvesting potential. Adequate dielectric hysteresis model is proposed to numerically determine the best configuration (frequency, amplitude) of electric field to impose. Even if the Ericsson technique requires external electronic devices, the weak consumption of such components allows a large enhancement of the amount of energy extracted compared to a basic piezo element conversion.

The response of an individual vortex to local mechanical contact

Recently we reported a new way to manipulate vortices in thin superconducting films by local mechanical contact without magnetic field, current or altering the pinning landscape [1]. We use scanning superconducting interference device (SQUID) microscopy to image the vortices, and a piezo element to push the tip of a silicon chip into contact with the sample. As a result of the stress applied at the contact point, vortices in the proximity of the contact point change their location. Here we study the characteristics of this vortex manipulation, by following the response of individual vortices to single contact events. Mechanical manipulation of vortices provides local view of the interaction between strain and nanomagnetic objects, as well as controllable, effective, localized, and reproducible manipulation technique.