Particular aspects of the tests for ignition of small components

The use of flammable substances in the industry means that the installations that process them generate explosion hazard zones in the proximal space. Equipment installed and operated in such hazardous areas must not ignite an explosive atmosphere. Confirmation of how equipment is adapted for use in an explosive atmosphere is named explosion protection. Explosion protection is confirmed by testing together with evaluation. For low-current equipment, the situation in which the hazardous atmosphere can be ignited by small components should be considered. The first part of the paper was devoted to the presentation of the explosion hazard and a brief presentation of the classification of equipment intended for use in explosive atmospheres. In the second part, the test methodology for ignition from small components is presented and in the last part, the results of ignition tests from small components are presented. The resulting main conclusion underlines the importance of test conditions

Exploring the meaning behind twitter hashtags through clustering

Abstract. Social networks are generators of large amount of data produced by users, who are not limited with respect to the content of the information they exchange. The data generated can be a good indicator of trends and topic preferences among users. In our paper we focus on analyzing and representing hashtags by the corpus in which they appear. We cluster a large set of hashtags using K-means on map reduce in order to process data in a distributed manner. Our intention is to retrieve connections that might exist between different hashtags and their textual representation, and grasp their semantics through the main topics they occur with

A Generalized and Simple Numerical Model to Compute the Feed Water Preheating System for Steam Power Plants

A general and simple numerical model is presented to calculate the uncontrolled steam flows extracted from a turbine to preheat the feed-water of a steam generator. For a user-defined technological scheme, a set of clear rules is given to complete the elements of the augmented matrix of the linear system that solves the problem. The model avoids writing of the heat balance equations for each heat exchanger. The steam extractions to the heaters are determined as related to the flow rate at the condenser. A numerical example is given to show the results

The Influence of Microwave Treatments on Bioactive Compounds and Antioxidant Capacity of <i>Mentha piperita</i> L.

Microwave extraction is becoming a popular option in many fields, especially for bioactive compounds from medicinal plants. This paper addresses the application of microwaves in the process of extracting bioactive compounds (phenols, flavonoids, chlorophyll) from peppermint with antioxidant capacity in order to highlight the influence of the microwave field on the quality of the final product in comparison with the control samples. The Mentha piperita L. is a rich source of phenols. The total phenol content after applying the MW treatments significant increased and varied between 25.000 ± 1.992 and 391.687 ± 20.537 mg GAE/100 g dw compared to the untreated sample (8.089 ± 2.745 mg GAE/100 g dw). The same trend was also recorded in the case of the flavonoid and pigment content in peppermint leaves following the application of microwave treatments. The obtained results were investigated using chemometric multivariate analysis. The main purpose of our research was to compare the possibilities of total or partial substitution of conventional extraction technologies with the microwave extraction technology, and also to highlight the existing differences in the amount of total phenols and flavonoids extracted from peppermint plants in different processing conditions. Through microwave processing, a significant increase in polyphenolic compounds is obtained

Hemorrhagic Cardiac Tamponade—An Unusual Threat in the COVID-19 Recovery Phase

Cardiac tamponade is a rare presentation in patients with COVID-19, which may be induced by the associated exacerbated inflammatory response. The onset of cardiac tamponade may be concomitant with the acute phase of the disease or may develop subsequently as a new health condition secondary to the disease. We report four cases of cardiac tamponade that occurred late after the acute phase of the disease. One of them may be considered a post-acute complication of the disease, and three of them may be classified as a new health condition induced by COVID-19. Only two cases had a history of severe respiratory distress due to COVID-19. In all four cases, pericardiocentesis was imposed, and surprisingly, in every case, hemorrhagic fluid was evacuated. In this case, series, immune-mediated etiology is supported by histopathological results, where the main identified feature was fibrous pericarditis with inflammatory infiltrate. Only one patient included in this report died, and three of them were discharged after anti-inflammatory treatment was initiated