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R Ravelo

Publications and source records attributed to R Ravelo.

9 recordsLinked to original sources
PubMed2000

Orientation dependence in molecular dynamics simulations of shocked single crystals

We use multimillion-atom molecular dynamics simulations to study shock wave propagation in fcc crystals. As shown recently, shock waves along the <100> direction form intersecting stacking faults by slippage along 111 close-packed planes at sufficiently high shock strengths. We find even more interesting behavior of shocks propagating in other low-index directions: for the <111> case, an elastic precursor separates the shock front from the slipped (plastic) region. Shock waves along the <110> direction generate a leading solitary wave train, followed (at sufficiently high shock speeds) by an elastic precursor, and then a region of complex plastic deformation.

Journal Article↗
PubMed1997

Laparoscopic jejunostomy with an 18-mm trocar.

We describe our technique to perform laparoscopic jejunostomies with an 18-mm trocar. This procedure facilitates the exteriorization of the proximal bowel and construction of the jejunostomy. We describe our laparoscopic technique in nine patients with severe neurologic conditions (two in the postoperative period of a cerebral aneurysm in a coma, three patients with severe head injury, and four patients with cerebrovascular strokes). The operative time ranged from 20 to 75 min (average, 44.38 min). Nutrition was initiated 24 h after the placement of the jejunostomy. Tolerance of the enteral nutrition was excellent in all cases. One major complication occurred, minor leakage around the feeding tube 3 weeks after the jejunostomy was constructed. The jejunostomy was removed without further consequences. Laparoscopy is an effective technique for the creation of feeding jejunostomies. We believe that this minimally invasive approach is an alternative for patients requiring long-term postpyloric enteral feeding.

Adult↗