Biomechanics of the Small Intestinal Contractions

The small intestine is a part of the gastrointestinal segment comprising of the duodenum, jejunum, and ileum. They help to process the gastric contents for further digestion, which involves mixing with duodeno-biliary-pancreatic (DBP) secretions to facilitate the chemical digestion, and homogenization of the luminal contents through contractions of the circular and longitudinal smooth muscle fibers of the intestine. The contractions of these smooth muscle fibers develops the mechanical forces at the mucosal wall, which as a consequence, transfers its momentum to the underlying fluid to develop the fluid flows, suggesting relevance of mechanics in physiology. The resulting flows are what drive the digestion. Changes in contractility of wave shapes of circular and longitudinal smooth muscle contractions and fluid rheology are known to affect the digestive process through generation of various flow patterns that differ in luminal pressure, peak velocity, extent of shearing/ mixing, volume of mixing, and flow rate. Recent studies indicate that the digestive process can be very specific such as to cause lipid digestion through segmental contractions and transport by eliciting propagating contractions, suggesting that the intestine manages to digest a variety of food in an efficient manner by eliciting appropriate contractions

Tribological behavior of the boric acid and titanium dioxide based nanofluid in machining of EN24 steel

Turning operation is a widely recognized metal removal process in the industry. If the machining were not run efficiently, it may affect the performance of the tool and the work piece by generating higher cutting forces and the temperature as in hard steel. To minimize these effects, lubrication has to be effective in reducing these forces and lowering the tool temperature. In the present study, machining experiments were conducted on EN24 steel with the application of nano sized boric acid (50 nm) as the solid lubricant that is mixed with titanium dioxide (100 µm) in SAE 40 oil. Turning tests are conducted using tungsten carbide tool inserts under dry, wet and MQL conditions to measure and compare the cutting forces, tool temperatures and roughness of the work piece. Results indicate that boric acid enables significant reduction in the cutting forces which in combination with the titanium dioxide helps to improve the heat dissipation; an advantage that makes such lubricants an effective cutting fluid. H3BO3 and TiO2 based nanofluid resulted in reducing the surface roughness of up to 2.7 µm that is a re-duction by ~15%