Energy efficiency improvement by the application of nanostructured coatings on axial piston pump slippers

Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when the pump (at low rotational speed or at partial displacement) works in the critical areas where the efficiency is low. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Due to the difficulty to reproduce the real working conditions of axial piston pump slippers, it has been made a hydraulic test bench properly designed in order to compare the performance of nano-coated slippers with respect to standard ones. The nano-coated and standard slippers have been subjected to the following working conditions: a test at variable pressure and constant rotational speed, a test at constant pressure and variable rotational speed. The comparison between standard and nanocoated slippers, for both working conditions, shows clearly that more than 20% of friction reduction can be achieved using the proposed nano-coating methodology

Recognition of Morphometric Vertebral Fractures by Artificial Neural Networks: Analysis from GISMO Lombardia Database

BACKGROUND: It is known that bone mineral density (BMD) predicts the fracture's risk only partially and the severity and number of vertebral fractures are predictive of subsequent osteoporotic fractures (OF). Spinal deformity index (SDI) integrates the severity and number of morphometric vertebral fractures. Nowadays, there is interest in developing algorithms that use traditional statistics for predicting OF. Some studies suggest their poor sensitivity. Artificial Neural Networks (ANNs) could represent an alternative. So far, no study investigated ANNs ability in predicting OF and SDI. The aim of the present study is to compare ANNs and Logistic Regression (LR) in recognising, on the basis of osteoporotic risk-factors and other clinical information, patients with SDI≥1 and SDI≥5 from those with SDI = 0. METHODOLOGY: We compared ANNs prognostic performance with that of LR in identifying SDI≥1/SDI≥5 in 372 women with postmenopausal-osteoporosis (SDI≥1, n = 176; SDI = 0, n = 196; SDI≥5, n = 51), using 45 variables (44 clinical parameters plus BMD). ANNs were allowed to choose relevant input data automatically (TWIST-system-Semeion). Among 45 variables, 17 and 25 were selected by TWIST-system-Semeion, in SDI≥1 vs SDI = 0 (first) and SDI≥5 vs SDI = 0 (second) analysis. In the first analysis sensitivity of LR and ANNs was 35.8% and 72.5%, specificity 76.5% and 78.5% and accuracy 56.2% and 75.5%, respectively. In the second analysis, sensitivity of LR and ANNs was 37.3% and 74.8%, specificity 90.3% and 87.8%, and accuracy 63.8% and 81.3%, respectively. CONCLUSIONS: ANNs showed a better performance in identifying both SDI≥1 and SDI≥5, with a higher sensitivity, suggesting its promising role in the development of algorithm for predicting OF

New high sensitivity MEMS sensor for indirect pressure measurement

Sensorization of modern electro-hydraulic systems is one of the key technologies for system observability and controllability. Increasing needs for closed loop controls, high precision, power control and energy monitoring, diagnosis and safety concerns, ask for both pressure and flow acquisition in industrial and mobile applications. Pressure sensors need specific coupling systems for mounting, and both pipes and components must be modified to install pressure sensors. Traditional pressure sensors are related to mini-mess and to oil flow modification in the sensor area. Direct pressure measurement is often made using thin film sensors whose measurement principle is related to a strain measurement. Modern Silicon based technologies offer new solutions for a less invasive pressure measurement. Micro Electro-Mechanical Systems (MEMS) Technology is suitable to design new sensors for indirect pressure measurement. This paper present a new MEMS resonant sensor, for low strain measurement that can be successfully used to indirectly measure oil pressure acquiring component’s strain measurement.Postprint (published version

Hydrostatic steering system and energy saving evaluation in idle regime

The main goal of modern steering systems is to ensure the feeling of control whilst keeping an high safety level since steering is one of the most critical function of a mobile machine. In manifold mobile machines the architecture include priority valves that on one hand increase safety, on the other increase the energy demand. In the present work a conceptual study of a novel steering system is outlined. With this architecture some reduction of fuel consumption can be obtained avoiding flow supply in idle condition. The system is separated from the rest of the hydraulic system thus the priority valve is not necessary. The aim of the system is to have the same characteristics of a classical system (with steering unit), with a better energy behavior in idle regime. Several simulations will be analyzed with the aim of studying the steering performance with emphasis on the steering wheel control characteristics in both normal and emergency operation.Postprint (published version

Hydrostatic steering system and energy saving evaluation in idle regime

The main goal of modern steering systems is to ensure the feeling of control whilst keeping an high safety level since steering is one of the most critical function of a mobile machine. In manifold mobile machines the architecture include priority valves that on one hand increase safety, on the other increase the energy demand. In the present work a conceptual study of a novel steering system is outlined. With this architecture some reduction of fuel consumption can be obtained avoiding flow supply in idle condition. The system is separated from the rest of the hydraulic system thus the priority valve is not necessary. The aim of the system is to have the same characteristics of a classical system (with steering unit), with a better energy behavior in idle regime. Several simulations will be analyzed with the aim of studying the steering performance with emphasis on the steering wheel control characteristics in both normal and emergency operation

Hydrostatic steering system and energy saving evaluation in idle regime

The main goal of modern steering systems is to ensure the feeling of control whilst keeping an high safety level since steering is one of the most critical function of a mobile machine. In manifold mobile machines the architecture include priority valves that on one hand increase safety, on the other increase the energy demand. In the present work a conceptual study of a novel steering system is outlined. With this architecture some reduction of fuel consumption can be obtained avoiding flow supply in idle condition. The system is separated from the rest of the hydraulic system thus the priority valve is not necessary. The aim of the system is to have the same characteristics of a classical system (with steering unit), with a better energy behavior in idle regime. Several simulations will be analyzed with the aim of studying the steering performance with emphasis on the steering wheel control characteristics in both normal and emergency operation

(Ti,Sn) Solid Solution Based Gas Sensors for New Monitoring of Hydraulic Oil Degradation

The proper operation of a fluid power system in terms of efficiency and reliability is directly related to the fluid state; therefore, the monitoring of fluid ageing in real time is fundamental to prevent machine failures. For this aim, an innovative methodology based on fluid vapor analysis through metal oxide (shortened: MOX) gas sensors has been developed. Two apparatuses were designed and realized: (i) a dedicated test bench to fast-age the fluid under controlled conditions; (ii) a laboratory MOX sensor system to test the headspace of the aged fluid samples. To prepare the set of MOX gas sensors suitable to detect the analytes’ concentrations in the fluid headspace, different functional materials were synthesized in the form of nanopowders, characterizing them by electron microscopy and X-ray diffraction. The powders were deposited through screen-printing technology, realizing thick-film gas sensors on which dynamical responses in the presence of the fluid headspace were obtained. It resulted that gas sensors based on solid solution TixSn1–xO2 with x = 0.9 and 0.5 offered the best responses toward the fluid headspace with lower response and recovery times. Furthermore, a decrease in the responses (for all sensors) with fluid ageing was observed

Energy efficiency improvement by the application of nanostructured coatings on axial piston pump slippers

Axial piston pumps and motors are widely used in heavy-duty applications and play a fundamental role in hydrostatic and power split drives. The mechanical power losses in hydraulic piston pumps come from the friction between parts in relative motion. The improvement, albeit marginal, in overall efficiency of these components may significantly impact the global efficiency of the machine. The friction between slipper and swash plate is a functional key in an axial piston pump, especially when the pump (at low rotational speed or at partial displacement) works in the critical areas where the efficiency is low. The application of special surface treatments have been exploited in pioneering works in the past, trying different surface finishing or adding ceramic or heterogeneous metallic layers. The potential of structured coatings at nanoscale, with superhydrophobic and oleophobic characteristics, has never been exploited. Due to the difficulty to reproduce the real working conditions of axial piston pump slippers, it has been made a hydraulic test bench properly designed in order to compare the performance of nano-coated slippers with respect to standard ones. The nano-coated and standard slippers have been subjected to the following working conditions: a test at variable pressure and constant rotational speed, a test at constant pressure and variable rotational speed. The comparison between standard and nanocoated slippers, for both working conditions, shows clearly that more than 20% of friction reduction can be achieved using the proposed nano-coating methodology

Novel Methodology Based on Thick Film Gas Sensors to Monitor the Hydraulic Oil Ageing

A new methodology for the real time monitoring of hydraulic oil aging based on the vapor analysis using metal oxide semiconductor (MOX) gas sensors has been successfully developed. A dedicated hydraulic test bench was designed and realized to age the oil under controlled condition. Gas chromatographic analyses were performed to detect oil volatile compounds (VOCs) and their concentrations at increasing oil working time. Moreover, a laboratory sensor system have been realized to test the headspace of the same samples. Both measurements highlighted a decrease of the VOCs concentrations

Clinical characteristics of all patients, patients without morphometric vertebral fractures, SDI≥1 and SDI≥5.

<p>Data are expressed as mean±SD, and median (range) for not normally distributed variables, if not differently specified.</p><p>*SDI = 0 vs SDI≥1; #SDI = 0 vs SDI≥5; SDI: Spinal Deformity Index; YSM: Years since menopause; BMI: Body Mass Index: weight (Kg)/height ² (m²); BF: breast feeding expressed in months; COPD: chronic obstructive pulmonary disease; T2D: Type 2 diabetes mellitus; SDI: Spinal Deformity Index calculated according to the method described by Crans (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027277#s2" target="_blank">Methods</a>);</p