Search results for "Mach"
showing 10 items of 3360 documents
A Study on the Correlations between Machining Parameters and Specimen Quality in WEDM
1999
Wire electrical discharge machining (WEDM) is widely used in manufacturing, medical, aircraft applications and, virtually, all areas of conductive material machining. The process involves a series of very complex electrical, thermodynamical and electromagnetical phenomena that are still partially unknown. Due to the large amount of parameters involved in the process, a suitable set-up of the variables aimed to obtain the best performance is often very difficult. In the paper the results of a wide experimental analysis are presented: the tests were carried out on high-speed steel and tempered steel specimens utilising brass wires. The influence of the most important process parameters on the…
3D DCE-MRI Radiomic Analysis for Malignant Lesion Prediction in Breast Cancer Patients
2022
Rationale and Objectives: To develop and validate a radiomic model, with radiomic features extracted from breast Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) from a 1.5T scanner, for predicting the malignancy of masses with enhancement. Images were acquired using an 8-channel breast coil in the axial plane. The rationale behind this study is to show the feasibility of a radio-mics-powered model that could be integrated into the clinical practice by exploiting only standard-of-care DCE-MRI with the goal of reducing the required image pre-processing (ie, normalization and quantitative imaging map generation).Materials and Methods: 107 radiomic features were extracted from a …
A negative rapid urease test is unreliable for exclusion of Helicobacter pylori infection during acute phase of ulcer bleeding
2003
Abstract Background. The reliability of the rapid urease test has not been proven in patients with peptic ulcer bleeding. Some studies show bad diagnostic results with the rapid urease test for gastrointestinal bleeding. Aims. To evaluate the efficacy of the rapid urease test in patients with bleeding gastric or duodenal ulcers. Patients and methods. A total of 96 patients with acute peptic ulcer bleeding without proton pump inhibitor or antibiotic therapy within the last 14 days before bleeding were included into the study. During index endoscopy, specimens for histological and rapid urease test were obtained from the antrum and corpus mucosa of the stomach. Patients were also investigated…
Circadian pattern of intragastric acidity in patients with non-erosive reflux disease (NERD)
2003
Summary Background : Most patients with gastro-oesophageal reflux disease have non-erosive reflux disease. Proton pump inhibitors are less effective than expected in these patients, but no previous study has measured their 24-h gastric pH values. Aims : To evaluate whether there are differences in 24-h intragastric acidity between reflux patients with and without oesophagitis and controls. The influence of Helicobacter pylori on the gastric pH of reflux patients was also assessed. Methods : Sixty-three consecutive patients with gastro-oesophageal reflux disease symptoms who agreed to undergo endoscopy and 24-h pH-metry were recruited. Twenty-five (39%) had erosive oesophagitis and 38 (61%) …
Diagnostic Accuracy of <sup>13</sup>C-Urea Breath Test in the Diagnosis of <i>Helicobacter pylori</i> Infection in Patients w…
2001
<i>Aims:</i> We investigated the diagnostic properties of the <sup>13</sup>C-urea breath test (<sup>13</sup>C-UBT) prospectively. These are well validated in nonresected patients before and after treatment of <i>Helicobacter pylori</i> infection but not in patients with partial gastric resection due to peptic ulcer disease. <i>Methods:</i> Hospitalized patients with previous gastric resection and indications for upper gastrointestinal endoscopy were recruited for the study. Biopsy specimens were obtained from the fundus mucosa and the gastric remnant adjacent to the gastroenteric anastomosis for histological examination and rapid u…
Investigating Centrality Measures in Social Networks with Community Structure
2021
Centrality measures are crucial in quantifying the influence of the members of a social network. Although there has been a great deal of work dealing with this issue, the vast majority of classical centrality measures are agnostic of the community structure characterizing many social networks. Recent works have developed community-aware centrality measures that exploit features of the community structure information encountered in most real-world complex networks. In this paper, we investigate the interactions between 5 popular classical centrality measures and 5 community-aware centrality measures using 8 real-world online networks. Correlation as well as similarity measures between both t…
Hybrid Methods for Robust Irradiance Analysis and 3-D Shape Reconstruction from Images
1994
The analysis of the differential structure of images is an interesting task in machine vision, among other reasons because it can provide relevant featural representation of images, suited for higher level information processing task like geometry reconstruction and object recognition. The importance of invariants of the field of isophotae on lambertian surfaces in shape perception by means of chiaroscuro is discussed in (Koenderink and Van Doom, 1980). In their approach to shape from shading, (Breton et al, 1992) represent the shading of the image by means of its shading flow field, i.e. by the first order differential structure of the image expressed as the isoluminance direction and grad…
A new reading of Bronze Age funerary structures in Mongolia through the analysis of their architectural elements, arrangement and form
2022
The archaeological landscape of Mongolia is marked by the presence of numerous funerary monuments (khirigsuurs) and engraved stelae (deer stones), erected by nomadic populations at the end of the Bronze Age. The first observations indicate great regularity in the choice and arrangement of the architectural and iconographic elements at the time when these structures were built. This regularity suggests the existence of shared traditions and social coherence between nomadic communities in a territory covering almost twice that of France. The data available today do not provide sufficient perspective to establish social models at the level of a province, and even less so at the scale of the co…
Back EMF Sensorless-Control Algorithm for High-Dynamic Performance PMSM
2010
In this paper, a low-time-consuming and low-cost sensorless-control algorithm for high-dynamic performance permanent-magnet synchronous motors, both surface and internal permanent-magnet mounted for position and speed estimation, is introduced, discussed, and experimentally validated. This control algorithm is based on the estimation of rotor speed and angular position starting from the back electromotive force space-vector determination without voltage sensors by using the reference voltages given by the current controllers instead of the actual ones. This choice obviously introduces some errors that must be vanished by means of a compensating function. The novelties of the proposed estima…
« Bultmann », « Luther », « Schleiermacher »
2013
International audience