A general extrudate bulk density model for both twin-screw and single-screw extruder extrusion cooking processes

Effects of extrusion parameters and raw materials on extrudate expansion are respectively investigated in a twin-screw extruder and a single-screw extruder extrusion cooking experiments for fish feed, wheat, and oat & wheat mixture processing. A new phenomenological model is proposed to correlated extrudate bulk density, extrusion parameters and raw material changes based on the experimental results. The average absolute deviation (AAD) of the correlation is 2.2% for fish feed extrusion in the twin-screw extrusion process. For the single-screw extrusion process, the correlation AAD is respectively 3.03%, 5.14% for wheat and oat & wheat mixture extrusion; and the correlation AAD is 6.6% for raw material change effects. The correlation results demonstrate that the proposed equation can be used to calculate extrudate bulk density for both the twin-screw extruder and the single-screw extruder extrusion cooking processes

Improving bioreactor performance using mobile sensors

Bioreactors are commonly used in bioprocessing. The dynamic real-time monitoring of some critical culture parameters becomes an essential process analytics tool (PAT) to characterize, qualify and validate the equipment. Mixing efficacy is seen as one of the main features to ensure an efficient outcome of a cell culture or a fermentation process. Inefficient mixing can result in zones of the bioreactor volume where the critical process parameters deviate from the operating range and therefore compromise process performance and quality. Freesense has developed an in-reactor sensor technology to provide data on the culture conditions from the whole internal volume of the bioreactor, which is not possible using traditional inline sensors. The technology consists of a mobile sensor which follows the flow in the bioreactor and measures parameters such as flow, temperature, pH and dissolved oxygen. In a case study, it was demonstrated that the Freesense sensor technology could transmit real-time data on temperature, pH and dissolved oxygen. Feasibility was confirmed in adapting the technology to single-use bioreactors in a biopharmaceutical environment, where the integration of these mobile sensors in a single-use assembly considering a more stringent sterile environment and cGMP conditions was investigated. Please click Additional Files below to see the full abstract

The development of a methodology to determine the relationship in grip size and pressure to racket head speed in a tennis forehand stroke

AbstractThis study developed a methodology to examine the effects of grip size and grip firmness on the kinematic contribution of angular velocity (KCAV) to the generation of racket head speed during a topspin tennis forehand. The KCAV is subdivided into kinematic contribution of joint angular velocity and kinematic contribution of the body segments in the upper trunk translational and angular velocities. Two Babolat Pure Storm GT rackets, with grip sizes 2 and 4 respectively, were used with Tekscan 9811E pressure sensors applied to the handles to examine pressure distribution during the stroke. Upper body kinematic data taken from the racket arm and trunk were obtained by means of a Vicon motion capture system. One elite male tennis player was recruited. Fifty topspin forehand strokes per grip at two nominal grip pressures were performed in a laboratory environment with balls being tossed towards the player and struck on the bounce towards a target on a net in as consistent a way as practically achievable.Processing of the results showed that the firm grip condition led to a significant (p<0.001) increase in average racket head speed compared to a normal grip condition. The normal gripping condition resulted in a significant (p<0.001) increase in average racket head speed for grip size 2 compared to grip size 4. A trend in negative linear relationships was found between upper trunk and shoulder joint in KCAV across conditions. Using the smaller grip also led to a trend in negative linear relationship between shoulder joint and wrist joint in KCAV across grip conditions. Grip pressure for grip size 2 showed the same pattern across gripping conditions. From 50-75% of completion in forward swing, the pressure difference due to grip firmness decreased. This feasibility study managed to quantify the KCAV while performing a topspin forehand, with respect to changing of grip size and grip pressure in an elite male tennis player for the first time