BACKGROUND Anatomic femoral tunnel placement for single-bundle anterior cruciate ligament (ACL) reconstruction is now well accepted. The ideal location for the tibial tunnel has not been studied extensively, although some biomechanical and clinical studies suggest that placement of the tibial tunnel in the anterior part of the ACL tibial attachment site may be desirable. However, the concern fo...

Some of the most difficult coal mine roof in the United States can be found in the Illinois Basin. Factors contributing to the high roof fall rate include weak, moisture-sensitive roof rock; high horizontal stress; and limited longwall mining. The depth of cover ranges from 27 to 300 m (90 to 1,000 ft), and roof damage from horizontal stress can be severe. Moisture-sensitive roof rock, which co...

The ongoing rush of the UE member states to the 2020 overall targets on the national renewable energy share (see Directive 2009/28/EC), is propelling the large exploitation of the solar resource for the electricity production. However, the incentives to the large employment of PV solar modules and the relative perspective profits, are often cause of massive ground-mounted installations. These k...

Because of the complications of impingement of anterior cruciate ligament grafts on the intercondylar roof and because current surgical procedures locate the tibial tunnel such that impingement is avoided during passive but not active extension, the objectives of this study were to determine if (a) active extension precipitates and aggravates roof impingement, and (b) a roofplasty mitigates the...

Microburst can produce downdraft and strong divergent outflow wind, whose characteristics are distinct from the atmospheric boundary layer (ABL) wind. In the present study, microburst-wind loading effects on low-rise structures a cubic-shaped building, a grain bin and two gable-roofed buildings – are evaluated and compared by performing laboratory tests on scaled models using a microburst simul...

This paper presents the residual mechanical properties of concrete made with crushed bricks and clay roof tile aggregates after exposure to high temperatures. One referent mixture and eight mixtures with different percentages of replacement of natural aggregate by crushed bricks and roof tiles are experimentally tested. The properties of the concrete were measured before and after exposure to 2...

Plinian and subplinian volcanic eruptions can be accompanied by tephra falls which may last hours or days, posing threats to people, buildings and economic activity. Numerous historical examples exist of tephra damage and tephra casualties. The mechanisms and consequences of roof collapse from static tephra load are an important area of tephra damage requiring more research. This paper contribu...

The heat loss and surface temperature of the top surface and sidewall of large-scale floating roof tank is tested by the heat flow meter and surface temperature method. Based on the test data, the heat loss from the top surface is about twice more than that of the sidewall which means the top surface is the weakest insulation part of the floating roof tank. On the surface, the heat loss profile...

Wood-frame residential roof failures are among the most common and expensive types of wind damage. Hip roofs are commonly understood to be more resilient during extreme wind in relation to gable roofs. However, inspection of damage survey data from recent tornadoes has revealed a previously unstudied failure mode in which hip roofs suffer partial failure of the framing structure. In the current...

Abstract This paper by reviewing the main examples of small to medium-scale retractable roof structures covering building courtyards is to present an innovative rigid retractable roof system employing spatial frames for a courtyard of an existing building in Tabriz Islamic Art University. The courtyard is currently used for temporary exhibitions and gatherings whenever permitted by environmenta...