This paper provides a tribochemical study of the selective layer surface by chemical mechanical planarization (CMP). CMP is used to remove excess material obtained in the process of selective transfer. The paper aims at a better understanding of the planarization (polishing) and micromachining. The planarization becomes effective if the material removal rate (MRR) is optimal and the surface defects are minimal. The pH of the slurry plays a very important role in removing the selective layer by CMP, and hydrogen peroxide (H 2 O 2 ) is the most common oxidizer used in CMP slurry. The purpose of this paper is the analysis of the pH effect on the etching rate (ER) and on the behavior of selective layer polishing by a constant concentration of H 2 O 2 and the influence of nanoparticles size and concentration on selective layer surface CMP. The nanoparticle size used is 250 nm. The MRR results through CMP and ER have been shown to be influenced by the presence of oxides on the selective layer surface and have been found to vary with the slurry pH at constant H 2 O 2 concentrations. The CMP slurry plays an important role in the CMP process performance and should be monitored for optimum results and minimal surface defects. The paper analyzes the impact of chemical-mechanical, inter-nanoparticle, and pad-nanoparticle-substrate interactions on CMP performance, taking into account the state of friction at the interface, by measuring the friction force. Selective layer CMP optimization studies were required to control the chemical and mechanical interactions at the interface between the slurry and the selective layer, the slurry chemistry, the properties, and the stability of the suspended abrasive nanoparticles.
Given the current context and the advanced stage of technology, which the braking systems of vehicles have reached, the main purpose of the studies and research is focused on presenting the main tribological aspects that contribute at improving the performance of braking systems, in order to ensure the vehicles’ safety and stability at braking, in any conditions. The performance of the braking system is a key factor for both producers and vehicle passengers, due to safety requirements, everincreasing. Thus, over time, numerous studies and research have been carried on in order to improve the performance of the braking system. In this paper are studied tribological phenomena through those, which contribute to the improvement of the braking system as performance, safety and stability.
In agrotechnical practice, it was found that between qualitative indices, which express the sowing precision achieved by precision planters determined in the laboratory, and those determined under operating conditions, that there are certain differences, which are sometimes quite significant. The decrease in the value of the quality indices was manifested by the increase of the number of mistakes, either of the number of double planting holes (with at least two seeds), or of the number of missing planting holes. Both cases are unfavorable for the agricultural producer, generating production losses. This paper discusses the influence of the degree of soil grinding on sowing precision in operating conditions, by determining the spectrum of the vibrations induced in the mechanical structure of row units of a precision planter in contact with the soil of three different plots for three working speeds: 4, 6, and 8 km·h−1. Later, the vibrations were simulated under laboratory conditions, on the stand, by means of rubber hemispheres (with diameters between 30 and 100 mm, corresponding to soil fractions resulting from the determination of the degree of soil grinding) mounted on rubber bands, which actuated the seed meters, for testing under an accelerated regime, outside of the optimal agricultural periods (out of season: beginning mid-May until the end of March), in order to obtain the accuracy of the precision planters. It was found that the sowing precision determined in stationary conditions on the stand, and on a plot with an appropriate degree of seedbed preparation, decreased between 2.92% (at 4 km·h−1) and 6.67% (at 8 km·h−1). The main objective of the tests was to reduce labor costs, which was necessary for the staff involved for determining the qualitative indices of work in real field operating conditions, eliminating fuel consumption, while reducing the duration of testing dependent on meteorological factors (season, temperatures, and precipitation, etc.).
The purpose of this paper is the numerical study of the effects of the fluid interaction with the blades of the working bodies of the renewable energy conversion systems. The paper presents the results of numerical research regarding the influence of the blade shape (straight), the number of blades (2, 3, 4) or the wind speed in the area on the output power of the small capacity wind turbines. The validation of the simulation data was performed by comparison with the experimental data obtained on a Windtrainer Junior laboratory wind energy system. Computed power coefficients are in good agreement with the experimental results. Increasing the efficiency of energy conversion for small wind turbines for their implementation in green farms represents a significant step in the concept of sustainable rural development.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.