Technical-scientific considerations regarding the reduction of the explosion effects generated by the explosive materials on persons and industrial and civil objectives

The attenuation is a function of a structural strength and mass of the PES structure. Relatively light or weak structures (or open PES facilities) are assumed to not attenuate any of the pressure or impulse load. These not-attenuating facilities include: Pre-engineered metal building, Hollow clay tile building, Trailer (drop or stand-alone), Tractor-trailer and Bulk/tank truck/Van truck. If there is a barricade present between the PES and the ES and this barricade meets certain criteria, the user can direct the model to reduce the pressure and impulse arriving at the ES because of the presence of the barricade. The fractional damage of the PES structure remaining intact after an explosive event is a function of the equivalent NEW (Net Explosive Weight) and the PES building type. The fractional damage (a value between 0 and 1) of each PES component (roof, front wall, side walls, and rear wall) is determined by comparing the NEW to lower-bound and upper-bound damage limits for the PES types. So, if the NEW is below the lower-bound damage limit value, then the PES structure is assumed to remain totally intact; if the NEW is greater than upper-bound damage limit value, then the PES structure is assumed to be completely destroyed; if the NEW value is between the lower-bound damage limit and upper-bound damage limit, the PES structure is partially or fractionally damaged. If the equivalent NEW is between the two values, an algorithm is used to determine how fast the PES structure transitions from zero damage to full damage as the NEW increases between the lower-bound damage limit and upper-bound damage limit values. This algorithm and all associated parameters are described in the following

Evaluation of the safety parameters for a permitted explosive type emulsion

When preparing a permitted explosive recipe an energy or an explosive heat is considered, which should ensure the detonability of the system and at the same time a power that satisfies the purpose for which it will be used, under the conditions of firedamp hazardous mines. The safety parameters for the explosive charges used in the firedamp hazardous mines are decisive, in order to ensure the safety and health requirements at work together with the efficient performance of the blasting operation. The permitted explosive type emulsion is recommended to be used in underground mines, open pit mines as a special methane explosive and can be used where a coal dust and/or methane explosion hazard exists can be loaded into dry and wet blasting holes and it can be used for mechanical loading. The permitted explosive type emulsion is a Detonator-sensitive explosives that can be reliably initiated in an unconfined state by a No. 8 strength detonator it have safety handling characteristics because of the relatively low sensitivity to friction, shock and impact. Technological changes due to the change of suppliers of certified explosives for civil use for underground use in the firedamp hazardous mines, involve reassessing the safety and efficiency of the loads made with these products, which have not been tested and evaluated for the conditions from the Jiu Valley mines

The importance of seismic protection of strategic objectives, in the area of influence of useful rock quarries, in which blasting works are carried out

In this scientific article was studied the main methods for assessing the seismic effect generated during the blasting operations with explosives, from quarries on essential infrastructure elements, in the analyzed situation - railway tunnel and supporting pillars of the railway superstructure in the adjacent area of the quarry, regarding the most appropriate technique for estimating and assessing the seismic effect through the specificity of the evaluated parameter. In order to be able to carry out an activity with as little impact as possible on the environment, the economic operator carrying out career blasting works must apply technical measures to ensure the protection of civil / industrial objectives in the area close to carrying out these works. The establishment of measures leading to the maintenance of the stability and integrity of the objectives, as well as to the protection of the environment, is based on an artificial earthquake assessment process, which highlights the possible effects on the adjacent area. The evaluation of the seismic effect can be done by monitoring some parameters that characterize the seismic waves produced by quarry blasting such as: frequency of oscillations, amplitude of movement, soil particles oscillations velocity, acceleration of oscillations, duration of their manifestation

Assessing the impact sensitivity of explosives using the BHF-12A equipment

The paper presents the results of the theoretical and practical research on the development of the technical and methodological infrastructure for assessing the safety parameter regarding the sensitivity to impact of explosives for civil use in order to increase the degree of security in their handling and use. The currently used method for determining the sensitivity to impact is based on the provisions of harmonized European Standard SR EN 13631-4. Expression of the results implies a particular experience of the research team, the conclusion of the test being in the form of a qualitative response reaction/non reaction to different energies (J) applied to the explosive samples, based on observed effects such as: smoke, explosion noise, flame / spark with or without combustion traces on the subassembly of the specialized test equipment. In order to carry out in good conditions the installation, use and maintenance of the specialized equipment for assessing the susceptibility of the tested substances to impact stimuli, the working procedure of the Department of Explosives and Pyrotechnic Products was elaborated and implemented, PL-04 working procedure with the designation “Working procedure for the installation, use and maintenance of BFH-12A type equipment designed to assess the sensitivity of test substances to impact stimuli”

Assessing the impact sensitivity of explosives using the BHF-12A equipment

The paper presents the results of the theoretical and practical research on the development of the technical and methodological infrastructure for assessing the safety parameter regarding the sensitivity to impact of explosives for civil use in order to increase the degree of security in their handling and use. The currently used method for determining the sensitivity to impact is based on the provisions of harmonized European Standard SR EN 13631-4. Expression of the results implies a particular experience of the research team, the conclusion of the test being in the form of a qualitative response reaction/non reaction to different energies (J) applied to the explosive samples, based on observed effects such as: smoke, explosion noise, flame / spark with or without combustion traces on the subassembly of the specialized test equipment. In order to carry out in good conditions the installation, use and maintenance of the specialized equipment for assessing the susceptibility of the tested substances to impact stimuli, the working procedure of the Department of Explosives and Pyrotechnic Products was elaborated and implemented, PL-04 working procedure with the designation “Working procedure for the installation, use and maintenance of BFH-12A type equipment designed to assess the sensitivity of test substances to impact stimuli”

Technical-scientific considerations regarding the reduction of the explosion effects generated by the explosive materials on persons and industrial and civil objectives

The attenuation is a function of a structural strength and mass of the PES structure. Relatively light or weak structures (or open PES facilities) are assumed to not attenuate any of the pressure or impulse load. These not-attenuating facilities include: Pre-engineered metal building, Hollow clay tile building, Trailer (drop or stand-alone), Tractor-trailer and Bulk/tank truck/Van truck. If there is a barricade present between the PES and the ES and this barricade meets certain criteria, the user can direct the model to reduce the pressure and impulse arriving at the ES because of the presence of the barricade. The fractional damage of the PES structure remaining intact after an explosive event is a function of the equivalent NEW (Net Explosive Weight) and the PES building type. The fractional damage (a value between 0 and 1) of each PES component (roof, front wall, side walls, and rear wall) is determined by comparing the NEW to lower-bound and upper-bound damage limits for the PES types. So, if the NEW is below the lower-bound damage limit value, then the PES structure is assumed to remain totally intact; if the NEW is greater than upper-bound damage limit value, then the PES structure is assumed to be completely destroyed; if the NEW value is between the lower-bound damage limit and upper-bound damage limit, the PES structure is partially or fractionally damaged. If the equivalent NEW is between the two values, an algorithm is used to determine how fast the PES structure transitions from zero damage to full damage as the NEW increases between the lower-bound damage limit and upper-bound damage limit values. This algorithm and all associated parameters are described in the following

CLINICAL AND MORPHOLOGICAL ASPECTS OF GINGIVAL OVERGROWTH INDUCED BY FIXED ORTHODONTIC THERAPY

Aim of the study The purpose of our study is to present the clinical aspects of gingival overgrowth induced by orthodontic therapy and to highlight the tissue changes of this gingival lesion. Materials and methods Biopsies of the gingival mucosa were taken from subjects diagnosed with gingival overgrowth and who were undergoing orthodontic therapy. The gingival mucosa samples were processed in the histology laboratory of University of Medicine and Pharmacy Craiova and the usual histological staining (hematoxylin-eosin) was performed. Results Gingival overgrowth (GO) is a condition characterized by an increase in gingival size, often observed in patients undergoing orthodontic therapy. The gingival enlargement begins o two or three months after the insertion of orthodontic appliance. The main causes of gingival overgrowth during orthodontic treatment include increased plaque accumulation due to challenges in maintaining oral hygiene with fixed appliances. Another cause is represented by the excessive pressure exerted by the orthodontic forces on the periodontium.Various factors influence the development of gingival overgrowth, including gender, age, and duration of orthodontic treatment. Conclusions Gingival overgrowth of orthodontic etiology can take on various clinical and morphological aspects and depends on the status of oral hygiene, the duration and correctness of orthodontic therapy