Examining the potential of damage in threat zones around LPG storage sphere in Hassi R’Mel city, Algeria

Purpose This study aims to determine the maximum extent of damage in the threat zones, the result of a catastrophic failure in one liquefied petroleum gas storage sphere, located in storage and transfer center in Hassi R’Mel city, Algeria. Design/methodology/approach To reach the desired results, we relied on ALOHA® v. 5.4.7 software (Areal Locations of Hazardous Atmospheres) for accidents simulation, and on Google Earth as an output tool to show results on the city map. Findings The results prove that the city of Hassi R’Mel is almost completely threatened by thermal effects resulting from a boiling liquid expanding vapor explosion phenomenon, which can reach a distance of 3.9 km. Originality/value Determining the extent to which the damages resulting from an industrial accident may reach is of great importance in preventing industrial hazards, as well as in decision-making in the field of urbanization.

FRACTURE RESISTANCE UNDER CYCLIC LOADING OF LITHIUM DISILICATE VONLAYS VERSUS ROSETTA VONLAYS RESTORING PREMOLARS (IN VITRO STUDY): مقاومة الكسر للقشور السطحية الخزفية المرممة للضواحك تحت تحميل دوري والمصنعة من الليثيوم ديسليكات مقابل القشور السطحية الخزفية المصنعة من الروزيتا: دراسة معملية

The aim of the study was to assess fracture resistance under cyclic loading of Rosetta®SM CAD vs. IPS e.max CAD (control) vonlays restoring maxillary premolars. According to the sample size calculation, a total of 20 samples will be selected and then divided into two equal groups; 10 sample each based on the material type: Group (A): Ten vonlays (n=10) manufactured from IPS e. max CAD blocks (control). Group ( B): Ten vonlays (n=10) manufactured from Rosetta®SM CAD blocks (intervention). A natural tooth presenting an upper first premolar was prepared in accordance with the ceramic onlay restorations preparation guidelines with an occlusal box with half of the bucco-lingual distance and a 2 mm depth from the cusp tip to pulpal floor, gingival seat with 1 mm depth from pulpal floor, occlusal reduction of 2 mm of the functional cusp with extending the preparation at the palatal surface by 2 mm in the cervical direction, occlusal reduction of 1.5 mm of non-functional cusp and 12º divergence angle. The preparation was then extended to the labial surface, with a 0.5 mm chamfer finish line. All line angles were finally rounded, and all margins were finished. For duplication of the natural tooth; the epoxy dies were constructed. Base and catalyst of the epoxy resin material were mixed as instructed by the manufacturer at a rate of 200r/min and then was poured into the silicon mould under vibration to eliminate any air voids, then was allowed to set completely following the manufacturer instructions for 24 hours, this procedure was repeated 20 times for creating 20 epoxy resin dies which replicating the prepared natural tooth. The die was then scanned by optical scanning using Medit i500 oral scanner. Milling of Vonlays was achieved using Sirona MCX5 milling machine using IPS e. max CAD blocks and Rosetta SM CAD blocks: 10 IPS e.max CAD blocks with block size C14 and 10 Rosetta®SM CAD blocks with block size C14 were used. Vonlays were then seated on their corresponding dies and cemented with dual cured self-adhesive resin cement (Variolink, Ivoclar Vivadent). Cementation procedures were performed by keeping each sample under a constant pressure of 5Kg using a custom designed cementation device for standardization the applied load during cementation process. All samples were mechanically aged (cyclic loading) to simulate 6 months of clinical use. Following that, all samples were subjected to fracture resistance testing under a compressive load to the center of their long axis using computer controlled universal testing machine with a load cell of 5 Kilo newton (K N) with a computer software used for data recording (Instron® Bluehill Lite Software). The mean values ± SDs values for e.max group were (502.39 ±102.89 N) with minimum value (338.16 N) and maximum value (721.29 N). The mean values ± SDs values. Rosetta group were (468.76 ± 67.54 N) with minimum value (367.11 N) and maximum value (648.48 N). Failure modes were determined under stereomicroscope and classified into repairable and catastrophic in both groups and showed that 60% of e.max group exhibited repairable failure while 40% of specimens showed catastrophic failure while in Rosetta group, 90% of the specimens exhibited repairable failure. Only 10% displayed catastrophic failure. Then a fractured part within each group was examined under scanning electron microscope (SEM) to reveal and compare their microstructure.

The Addition of a Krackow Rip Stop Suture Augment After Achilles Tendon Debridement for Insertional Achilles Tendinopathy: A Biomechanical Study

Background In the operative treatment of insertional Achilles tendinopathy, the Achilles tendon is often released from its insertion to allow for adequate debridement of pathologic tissue. The use of a double row suture anchor construct has become increasingly favorable among surgeons after Achilles tendon debridement. This study hypothesized that the addition of a Krackow rip stop suture augment to the double row suture anchor construct would increase the repair’s maximum load to failure. A biomechanically stronger repair would potentially decrease the risk of catastrophic failure with early weight-bearing or accidental forced dorsiflexion after operative management for insertional Achilles tendinopathy. Methods Fourteen cadaveric specimens were used to compare the 2 repair techniques. Achilles tendons were debrided and repaired using either a double row suture anchor with and without the additional Krackow rip stop suture augment. The 2 repair techniques were compared using an axial-torsion testing system to measure average load to failure. Results The average load to failure for the double row suture anchor repair alone was 152.00 N. The average load to failure for the tendons with the double row suture anchor with the Krackow rip stop augment was 383.08 N. An independent-samples Mann-Whitney U-test was conducted and the suture anchor plus Krackow augment group had a significantly higher load to failure ( P = .011, Mann-Whitney U = 5.00, n1 = n2 = 7, P < .05, 2-tailed). Conclusion This study confirmed that the addition of a Krakow rip stop augment to the double row suture anchor is able to increase the maximum load to failure when compared to the double row suture anchor alone. These results suggest the potential of this added technique to decrease the risk of catastrophic failure.

Fracture Network Localization Preceding Catastrophic Failure in Triaxial Compression Experiments on Rocks

We quantify the spatial distribution of fracture networks throughout six in situ X-ray tomography triaxial compression experiments on crystalline rocks at confining stresses of 5–35 MPa in order to quantify how fracture development controls the final macroscopic failure of the rock, a process analogous to those that control geohazards such as earthquakes and landslides. Tracking the proportion of the cumulative volume of fractures with volumes &gt;90th percentile to the total fracture volume, ∑v90/vtot indicates that the fracture networks tend to increase in localization toward these largest fractures for up to 80% of the applied differential stress. The evolution of this metric also matches the evolution of the Gini coefficient, which measures the deviation of a population from uniformity. These results are consistent with observations of localizing low magnitude seismicity before large earthquakes in southern California. In both this analysis and the present work, phases of delocalization interrupt the general increase in localization preceding catastrophic failure, indicating that delocalization does not necessarily indicate a reduction of seismic hazard. However, the proportion of the maximum fracture volume to the total fracture volume does not increase monotonically. Experiments with higher confining stress tend to experience greater localization. To further quantify localization, we compare the geometry of the largest fractures, with volumes &gt;90th percentile, to the best fit plane through these fractures immediately preceding failure. The r2 scores and the mean distance of the fractures to the plane indicate greater localization in monzonite than in granite. The smaller mean mineral diameter and lower confining stress in the granite experiments may contribute to this result. Tracking these various metrics of localization reveals a close association between macroscopic yielding and the acceleration of fracture network localization. Near yielding, ∑v90/vtot and the Gini coefficient increase while the mean distance to the final failure plane decreases. Macroscopic yielding thus occurs when the rate of fracture network localization increases.