Temperature changes in dental pulp associated with use of power grinding equipment on equine teeth

Objective To quantify the temperature changes in the dental pulp associated with equine dental procedures using power grinding equipment. Design A matrix experimental design with replication on the same sample was followed to allow the following independent variables to be assessed: horse age (young or old), tooth type (premolar or molar), powered grinding instrument (rotating disc or die grinder), grinding time (15 or 20 seconds) and the presence or absence of water coolant. Procedure Sound premolar and molar teeth from a 6-year-old horse and a 15-year-old horse, which had been removed postmortem, were sectioned parallel to the occlusal plane to allow placement of a miniature thermocouple at the level of the dental pulp. The maximum temperature increase, the time taken to reach this maximum and the cooling time were measured (n=10 in each study). The teeth were placed in a vice and the instrument used on the tooth as per clinical situation. Results Significant differences were recorded for horse age (P < 0.001), instrument type (P < 0.001), grinding time (P < 0.001) and presence or absence of coolant (P < 0.001). There was no significant difference for tooth type. Conclusion Thermal insult to the dental pulp from the use of power instruments poses a significant risk to the tooth. This risk can be reduced or eliminated by appropriate selection of treatment time and by the use of water irrigation as a coolant. The increased dentine thickness in older horses appears to mitigate against thermal injury from frictional heat.

Risk-based decision making method for maintenance policy selection of thermal power plant equipment

This study presents a decision-making method for maintenance policy selection of power plants equipment. The method is based on risk analysis concepts. The method first step consists in identifying critical equipment both for power plant operational performance and availability based on risk concepts. The second step involves the proposal of a potential maintenance policy that could be applied to critical equipment in order to increase its availability. The costs associated with each potential maintenance policy must be estimated, including the maintenance costs and the cost of failure that measures the critical equipment failure consequences for the power plant operation. Once the failure probabilities and the costs of failures are estimated, a decision-making procedure is applied to select the best maintenance policy. The decision criterion is to minimize the equipment cost of failure, considering the costs and likelihood of occurrence of failure scenarios. The method is applied to the analysis of a lubrication oil system used in gas turbines journal bearings. The turbine has more than 150 MW nominal output, installed in an open cycle thermoelectric power plant. A design modification with the installation of a redundant oil pump is proposed for lubricating oil system availability improvement. (C) 2009 Elsevier Ltd. All rights reserved.

Getting started with power tools; a basic readily understandable book on the fundamental operations of power-tool equipment.

Mode of access: Internet.

A Competitive assessment of the U.S. electric power generating equipment industry /

Item 231-B-1.

The Tractor field book, with power farm equipment specifications.

Title varies slightly.

Study of thresholds to burning in surface grinding process

This work aims at finding out the threshold to burning in surface grinding process. Acoustic emission and electric power signals are acquired from an analog-digital converter and processed through algorithms in order to generate a control signal to inform the operator or interrupt the process in the case of burning occurrence. The thresholds that dictate the situation of burn and non-burn were studied as well as a comparison between the two parameters was carried out. In the experimental work one type of steel (ABNT-1045 annealed) and one type of grinding wheel referred to as TARGA model 3TG80.3-NV were employed. Copyright © 2005 by ABCM.

In-process grinding monitoring through acoustic emission

This work aims to investigate the efficiency of digital signal processing tools of acoustic emission signals in order to detect thermal damages in grinding processes. To accomplish such a goal, an experimental work was carried out for 15 runs in a surface grinding machine operating with an aluminum oxide grinding wheel and ABNT 1045 Steel as work material. The acoustic emission signals were acquired from a fixed sensor placed on the workpiece holder. A high sampling rate data acquisition system working at 2.5 MHz was used to collect the raw acoustic emission instead of the root mean square value usually employed. Many statistical analyses have shown to be effective to detect burn, such as the root mean square (RMS), correlation of the AE, constant false alarm rate (CFAR), ratio of power (ROP) and mean-value deviance (MVD). However, the CFAR, ROP, Kurtosis and correlation of the AE have been presented more sensitive than the RMS. Copyright © 2006 by ABCM.

Monitoring the dressing operation in the grinding process

This work was based on a methodology of development and experimentation, and involved monitoring the dressing operation by processing the acoustic emission and electric power signals to detect the optimal dressing moment. Dressing tests were performed in a surface grinding machine with an aluminium grinding wheel. Dressing analysis software was developed and used to process the signals collected earlier in order to analyse not only the dressing parameters but also the software's ability to indicate the instant when the dressing operation could be concluded. Parameters used in the study of burn in grinding were implemented in order to ascertain if they would also prove efficient in monitoring dressing. A comparative study revealed that some parameters are capable of monitoring the dressing operation. It was possible to verify the parameters effectiveness that today are utilised in burning to monitor dressing as well as to create new parameters for monitoring this operation. Copyright © 2009, Inderscience Publishers.

Anfis applied to the prediction of surface roughness in grinding of advanced ceramics

This paper introduces a methodology for predicting the surface roughness of advanced ceramics using Adaptive Neuro-Fuzzy Inference System (ANFIS). To this end, a grinding machine was used, equipped with an acoustic emission sensor and a power transducer connected to the electric motor rotating the diamond grinding wheel. The alumina workpieces used in this work were pressed and sintered into rectangular bars. Acoustic emission and cutting power signals were collected during the tests and digitally processed to calculate the mean, standard deviation, and two other statistical data. These statistics, as well the root mean square of the acoustic emission and cutting power signals were used as input data for ANFIS. The output values of surface roughness (measured during the tests) were implemented for training and validation of the model. The results indicated that an ANFIS network is an excellent tool when applied to predict the surface roughness of ceramic workpieces in the grinding process.

Study of the Electromagnetic Interference Generated by Wireless Power Transfer Systems

This paper presents a study related with measuring of radio frequency emissions. The purpose is to determine the level of interference generated by wireless power transfer equipment in a specific frequency range, and to compare those levels to the existing standards. The technology of wireless power transfer, especially for electric vehicles batteries charging, is rapidly developing in the recent years. An increasing use of this technology in industrial and consumer electronic products has raised concerns about the possible unfavorable health-effects onto the human being. Another concern is raised from the high intensity fields produced by wireless power transfer systems which will generate highly undesired influence on other electrical and electronic equipment. As a protection against the potential health effects, the governments imposed limits on the occupational and general public exposure to the radio frequencies. These limitations are set out in national and international safety guidelines, standards and regulations. The measurement and evaluation of the human exposure to electromagnetic fields are essential to guarantee occupational and general public safety.

Boost converter

In this project, we want to implement a theoretical typology of a converter, the Boost converter, which is also named “Step-up converter”. We also want to bring it to the practical area, where we could work and obtain a useful service, particularly our objective is to obtain a power supply for a notebook. We will give the possibility to work, charge etc. our device in the car and obtain another work station

Tiedonkeruujärjestelmän kehittäminen voimalaitoksen toiminnan tehostamisessa

Diplomityössä kehitetään tiedonkeruujärjestelmää voimalaitoksen toiminnan tehostamiseksi. Aihetta käsitellään tiedonkeruujärjestelmän käyttäjän ja ylläpitäjän näkökulmasta. Tiedonkeruujärjestelmällä kerätään prosessitietoa automaatiojärjestelmästä ja tallennetaan prosessitieto tietokantaan. Työssä on kuvattu sekä automaatio- että tiedonkeruujärjestelmää prosessitiedon keruun, tallentamisen ja hallinnan ymmärtämiseksi. Prosessitiedon merkitystä voimalaitoksen toiminnan kannalta on myös pohdittu. Diplomityö tehtiin Mertaniemen voimalaitoksella, jossa käytännön kehityskohteina olivat laskenta- ja raportointisovellukset. Lisäksi tarkistettiin tietokantamuuttujia. Tiedonkeruujärjestelmää kehitetään ja päivitetään voimalaitoksen laitteisto- ja toimintamuutosten takia. Kehityksellä pyritään tarjoamaan oikeampaa ja luotettavampaa tietoa, korjaamaan virheitä sekä kartoittamaan mahdollisia puutteita.

Automatic system for thermal damage detection in manufacturing process with Internet monitoring

This work involved the development of a smart system dedicated to surface burning detection in the grinding process through constant monitoring of the process by acoustic emission and electrical power signals. A program in Visual Basic® for Windows® was developed, which collects the signals through an analog-digital converter and further processes them using burning detection algorithms already known. Three other parameters are proposed here and a comparative study carried out. When burning occurs, the newly developed software program sends a control signal warning the operator or interrupting the process, and delivers process information via the Internet. Parallel to this, the user can also interfere in the process via Internet, changing parameters and/or monitoring the grinding process. The findings of a comparative study of the various parameters are also discussed here. Copyright © 2006 by ABCM.

Development of a DC-DC converter for DC bus voltage control of series connected device

The purpose of this work is to study voltage control and energy balance of a split DC bus topology within a power electronics equipment connected to the AC mains, such as UPS systems, wind power generators, active filters and FACTS devices. A typical configuration in such equipment has two mains connected converters sharing a common DC bus, one series connected and the other parallel connected. The DC bus is usually composed by a battery or a capacitor bank. In the proposed topology, the DC bus is divided in two sides, interconnected with a buck-boost converter, which controls power flow and DC voltage on both sides. © 2009 IEEE.

Utilização de resíduos e derivados de madeira para confecção de uma guitarra elétrica

The residues generation is a quite serious problem in several industrial areas and also in the lumbering area. The search for the elimination or reduction of the volume of generated residues is endless, however limited, resulting in the search for a proper destination or better use, instead of simply burning it. A lot of uses and services are commonly proposed, but with low aggregated value to the residue. This work shows the usage viability of different discarded residues and wood composites in the production of an electric guitar. Cupiúba, ipê and jatobá residues have been used besides wood composites of pinus. The residues and wood composites have shown appropriate resistance, surfacing quality and design terms, and could be used to substitute the traditionally wood used in the production of the instrument as well as in other products of similar characteristics and with larger aggregated value.