Kompaktowe narzędzie elektrohydrauliczne o dużej mocy do rozbijania obiektów z betonu i skał kopalnianych podczas działań ratowniczych

Aim: To ensure the safety of people during rescue operations who are engaged with the removal of rubble from destroyed buildings. Introduction: There are a large number of approaches used in dismantling and demolishing concrete structures during rescue operations. These include: explosives, pneumatic and hydraulic equipment, and petrol power cutters. Each of the known methods, in addition to advantages, has disadvantages. Therefore, there is a need to develop new and effective methods of dismantling and demolishing concrete structures. The authors propose utilization of an electro-hydraulic approach based on the use of plasma energy, which is generated when an electrical discharge occurs in a receptacle filled with water. A concrete structure is perforated with cylindrical holes, which are then filled with water. Special electrodes are inserted into the holes. After the insertion of special electrodes an electrical discharge is generated. This leads to the formation of an expanding plasma. Induced shock waves combined with water cause a mechanical stress to the structure being demolished. To achieve this goal it was necessary to address the following: – Perform an analysis of possible alternative devices, bearing in mind the purpose – Develop and prototype elements of the device – Produce and assemble elements of the device and test the laboratory model . – Analyze results of laboratory tests, eliminate identified defects, refine and adjust electric circuit and construction of the device. – Finalise a working model of the device and perform field trials. Conclusions: The developed device may be used to break up standard bricks and building structures. Power of the device can vary, depending on the size of the structure, which is being dismantled. An industrial sized device may be transported by a vehicle with a light duty chassis. Implications for practice: Protection of life and health of people, near to or buried under rubble. Ability to demolish bulky concrete structures. Elimination of harmful substance emissions. Avoidance of impact from shock and acoustic waves, flying debris and ability to set a course for a breach in a wall.Cel: Zagwarantowanie bezpieczeństwa ludzi w czasie odgruzowywania zniszczonych budynków podczas działań ratowniczych. Wstęp: Istnieje wiele metod rozbiórki i rozbijania konstrukcji z betonu podczas prowadzenia działań ratowniczych (np. użycie materiałów wybuchowych, sprzętu i narzędzi pneumatycznych i hydraulicznych oraz palnika benzynowego do cięcia tlenem itd.). Każda ze znanych metod ma nie tylko zalety, ale też i wady. Dlatego konieczne jest opracowanie nowych skutecznych metod niszczenia konstrukcji betonowych. W artykule autorzy zaproponowali wykorzystywanie metod elektrohydraulicznych, opartych na energii plazmy powstającej podczas wyładowania elektrycznego w przestrzeni wypełnionej wodą. W konstrukcji betonowej znajdują się otwory strzałowe, które wypełnia się wodą. Po wprowadzeniu do otworów specjalnych elektrod przeprowadza się wyładowanie elektryczne. Prowadzi ono do wytworzenia się powiększającej się plazmy. Fale uderzeniowe z wodą prowadzą do naprężenia mechanicznego niszczonego obiektu. Aby osiągnąć wyznaczony cel, należało: – przeprowadzić analizę możliwych alternatywnych wariantów urządzenia, biorąc pod uwagę jego przeznaczenie; – opracować i przygotować modele konkretnych mechanizmów i bloków urządzenia; – przygotować i przeprowadzić połączenie mechanizmów i bloków urządzenia, przeprowadzić prace montażowe i badania laboratoryjne modelu urządzenia; – przeprowadzić analizę badań laboratoryjnych urządzenia, wyeliminować wykryte wady, dopracować i poprawić schemat elektryczny i konstrukcję urządzenia; – opracować model urządzenia i przeprowadzić jego badania w terenie. Wnioski: Opracowane urządzenie może być używane do rozbijania standardowych bloczków i konstrukcji budowlanych. Moc urządzenia może być dostosowana do rozmiaru niszczonej konstrukcji. Model przemysłowy urządzenia może być przewożony samochodem z podwoziem o małej nośności

Apixaban versus warfarin in patients with atrial fibrillation

BACKGROUND: Vitamin K antagonists are highly effective in preventing stroke in patients with atrial fibrillation but have several limitations. Apixaban is a novel oral direct factor Xa inhibitor that has been shown to reduce the risk of stroke in a similar population in comparison with aspirin. METHODS: In this randomized, double-blind trial, we compared apixaban (at a dose of 5 mg twice daily) with warfarin (target international normalized ratio, 2.0 to 3.0) in 18,201 patients with atrial fibrillation and at least one additional risk factor for stroke. The primary outcome was ischemic or hemorrhagic stroke or systemic embolism. The trial was designed to test for noninferiority, with key secondary objectives of testing for superiority with respect to the primary outcome and to the rates of major bleeding and death from any cause. RESULTS: The median duration of follow-up was 1.8 years. The rate of the primary outcome was 1.27% per year in the apixaban group, as compared with 1.60% per year in the warfarin group (hazard ratio with apixaban, 0.79; 95% confidence interval [CI], 0.66 to 0.95; P<0.001 for noninferiority; P = 0.01 for superiority). The rate of major bleeding was 2.13% per year in the apixaban group, as compared with 3.09% per year in the warfarin group (hazard ratio, 0.69; 95% CI, 0.60 to 0.80; P<0.001), and the rates of death from any cause were 3.52% and 3.94%, respectively (hazard ratio, 0.89; 95% CI, 0.80 to 0.99; P = 0.047). The rate of hemorrhagic stroke was 0.24% per year in the apixaban group, as compared with 0.47% per year in the warfarin group (hazard ratio, 0.51; 95% CI, 0.35 to 0.75; P<0.001), and the rate of ischemic or uncertain type of stroke was 0.97% per year in the apixaban group and 1.05% per year in the warfarin group (hazard ratio, 0.92; 95% CI, 0.74 to 1.13; P = 0.42). CONCLUSIONS: In patients with atrial fibrillation, apixaban was superior to warfarin in preventing stroke or systemic embolism, caused less bleeding, and resulted in lower mortality. Copyright © 2011 Massachusetts Medical Society. All rights reserved

Apixaban compared with warfarin in patients with atrial fibrillation and previous stroke or transient ischaemic attack: A subgroup analysis of the ARISTOTLE trial

Background: In the ARISTOTLE trial, the rate of stroke or systemic embolism was reduced by apixaban compared with warfarin in patients with atrial fibrillation (AF). Patients with AF and previous stroke or transient ischaemic attack (TIA) have a high risk of stroke. We therefore aimed to assess the efficacy and safety of apixaban compared with warfarin in prespecified subgroups of patients with and without previous stroke or TIA. Methods: Between Dec 19, 2006, and April 2, 2010, patients were enrolled in the ARISTOTLE trial at 1034 clinical sites in 39 countries. 18 201 patients with AF or atrial flutter were randomly assigned to receive apixaban 5 mg twice daily or warfarin (target international normalised ratio 2·0-3·0). The median duration of follow-up was 1·8 years (IQR 1·4-2·3). The primary efficacy outcome was stroke or systemic embolism, analysed by intention to treat. The primary safety outcome was major bleeding in the on-treatment population. All participants, investigators, and sponsors were masked to treatment assignments. In this subgroup analysis, we estimated event rates and used Cox models to compare outcomes in patients with and without previous stroke or TIA. The ARISTOTLE trial is registered with ClinicalTrials.gov, number NTC00412984. Findings: Of the trial population, 3436 (19%) had a previous stroke or TIA. In the subgroup of patients with previous stroke or TIA, the rate of stroke or systemic embolism was 2·46 per 100 patient-years of follow-up in the apixaban group and 3·24 in the warfarin group (hazard ratio [HR] 0·76, 95% CI 0·56 to 1·03); in the subgroup of patients without previous stroke or TIA, the rate of stroke or systemic embolism was 1·01 per 100 patient-years of follow-up with apixaban and 1·23 with warfarin (HR 0·82, 95% CI 0·65 to 1·03; p for interaction=0·71). The absolute reduction in the rate of stroke and systemic embolism with apixaban versus warfarin was 0·77 per 100 patient-years of follow-up (95% CI -0·08 to 1·63) in patients with and 0·22 (-0·03 to 0·47) in those without previous stroke or TIA. The difference in major bleeding with apixaban compared with warfarin was 1·07 per 100 patient-years (95% CI 0·09-2·04) in patients with and 0·93 (0·54-1·32) in those without previous stroke or TIA. Interpretation: The effects of apixaban versus warfarin were consistent in patients with AF with and without previous stroke or TIA. Owing to the higher risk of these outcomes in patients with previous stroke or TIA, the absolute benefits of apixaban might be greater in this population. Funding: Bristol-Myers Squibb and Pfizer. © 2012 Elsevier Ltd