Production of ethyl dodecanoate (biodiesel) using lauric acid and methanol with a solid acid catalyst of sulfated zirconia is studied by using two distillation sequences. In the first sequence, the methanol recovery column follows the reactive distillation column. In the second sequence, the reactive distillation and methanol recovery columns are thermally coupled. Thermally coupled distillatio...

We investigate the extent to which quantities that are based on total column ozone are applicable as measures of ozone loss in the polar vortices. Such quantities have been used frequently in ozone assessments by the World Meteorological Organization (WMO) and also to assess the performance of chemistry-climate models. The most commonly considered quantities are March and October mean column oz...

BACKGROUND The aim of this study was to explore the surgical treatment of transverse with or without posterior wall fractures of the acetabulum. MATERIAL AND METHODS We surgically treated 21 consecutive cases of pure transverse (7 cases) and with posterior wall (14 cases) fractures of the acetabulum. The anterior column fractures were firstly reduced, temporarily fixed through a modified Smith-...

Percutaneous screw insertion for minimally displaced or reducible acetabular fracture using x-ray fluoroscopy and computer-assisted navigation system has been advocated by some authors. The purpose of this study was to compare intraoperative conditions and clinical results between isocentric C-arm 3-dimensional (Iso-C 3D) fluoroscopy and conventional fluoroscopy for percutaneous retrograde scre...

A new laser printer, a case for your cell phone, protective glass phone’s screen, the next generation of Logitech’s wireless mouse, and loss connectivity older Kindle electronic readers are topics this column.

this paper focuses on using the recently developed extended finite element model for buckling analysis of edge cracked columns under concentric axial load. the effect of crack depth and its location on the carrying capacity of columns is studied. the effect of different boundary conditions is also investigated. numerical examples are offered to show the efficiency and effectiveness of the propo...

Nitrogen is a key limiting nutrient that influences marine productivity and carbon sequestration in the ocean via the biological pump. In this study, we present the first estimates of nitrogen cycling in a coupled 3D ocean-biogeochemistry-isotope model forced with realistic boundary conditions from the Last Glacial Maximum (LGM) ∼21,000 years before present constrained by nitrogen isotopes. The...

A rigorous model for the simulation of the dynamic behaviour of distillation column including pressure relief has been developed. This model allows the analysis of the influence of different disturbances (failures) on the dynamic behaviour of a methanol/water column. Disturbances of the cooling medium supply to the condenser and the reflux stream have been examined. In this paper the results of...