Rapidly drying sorghum biomass for potential biofuel production

The Southern U.S. has an ideal climate that may aid in growing large amounts of biomass suitable for biofuel; however, droughts during the growing season may reduce yields.  Sorghum (Sorghum bicolor L.) may have great potential as an energy crop, because it is capable of high biomass yields and is drought tolerant. However, sorghum biomass has relatively high moisture content and should be conditioned and dried before transported to reduce costs.  Sorghum-sudan hybrid was harvested with two different headers on a self-propelled windrower:  a Massey Ferguson 9145 (sickle) and a Massey Ferguson 9185 (disc).  The disc header was comprised of two pairs (rear front) of metal conditioner rollers which compressed the biomass, thus improving the drying process. The roller pairs were used with three different pressures (0, 3500 and 7,000 kPa), and with different gaps (0 and 0.02 m). Sorghum biomass samples were collected after harvest and the percentage of moisture content wet basis evaluated daily until they remained constant. Results revealed that the higher pressures and smaller gaps resulted in faster drying of biomass. Thus, the best settings for the disc header were “7,000 kPa -0 m” or “7,000 kPa - 0.02 m” which showed, respectively, moisture content levels of 13.6% and 16.8% after 14 days. However, when the disc header was set to “0 kPa - 0.02 m”, the moisture content was significantly higher (43.2%).  These results indicate sorghum was adequately dried for bailing in Southeastern U.S. condition, when proper machinery and settings were applied.   Keywords: moisture, sorghum, baling, windrower

Effects of a nanoscopic filler on the structure and dynamics of a simulated polymer melt and the relationship to ultra-thin films

We perform molecular dynamics simulations of an idealized polymer melt surrounding a nanoscopic filler particle to probe the effects of a filler on the local melt structure and dynamics. We show that the glass transition temperature $T_g$ of the melt can be shifted to either higher or lower temperatures by appropriately tuning the interactions between polymer and filler. A gradual change of the polymer dynamics approaching the filler surface causes the change in the glass transition. We also find that while the bulk structure of the polymers changes little, the polymers close to the surface tend to be elongated and flattened, independent of the type of interaction we study. Consequently, the dynamics appear strongly influenced by the interactions, while the melt structure is only altered by the geometric constraints imposed by the presence of the filler. Our findings show a strong similarity to those obtained for ultra-thin polymer films (thickness $\lesssim 100$ nm) suggesting that both ultra-thin films and filled-polymer systems might be understood in the same context

Spin relaxation: From 2D to 1D

In inversion asymmetric semiconductors, spin-orbit interactions give rise to very effective relaxation mechanisms of the electron spin. Recent work, based on the dimensionally constrained D'yakonov Perel' mechanism, describes increasing electron-spin relaxation times for two-dimensional conducting layers with decreasing channel width. The slow-down of the spin relaxation can be understood as a precursor of the one-dimensional limit

Clockwise torque results in higher reoperation rates in left-sided femur fractures

Purpose: Effects of clockwise torque rotation onto proximal femoral fracture fixation have been subject of ongoing debate: fixated right-sided trochanteric fractures seem more rotationally stable than left-sided fractures in the biomechanical setting, but this theoretical advantage has not been demonstrated in the clinical setting to date. The purpose of this study was to identify a difference in early reoperation rate between patients undergoing surgery for left-versus right-sided proximal femur fractures using cephalomedullary nailing (CMN). Materials and methods: The American College of Surgeons National Surgical Quality Improvement Program was queried from 2016-2019 to identify patients aged 50 years and older undergoing CMN for a proximal femoral fracture. The primary outcome was any unplanned reoperation within 30 days following surgery. The difference was calculated using a Chi-square test, and observed power calculated using post-hoc power analysis. Results: In total, of 20,122 patients undergoing CMN for proximal femoral fracture management, 1.8% (n=371) had to undergo an unplanned reoperation within 30 days after surgery. Overall, 208 (2.0%) were left-sided and 163 (1.7%) right-sided fractures (p=0.052, risk ratio [RR] 1.22, 95% confidence interval [CI] 1.00-1.50), odds ratio [OR] 1.23 (95%CI 1.00-1.51), power 49.2% (& alpha;=0.05). Conclusion: This study shows a higher risk of reoperation for left-sided compared to right-sided proximal femur fractures after CMN in a large sample size. Although results may be underpowered and statistically insignificant, this finding might substantiate the hypothesis that clockwise rotation during implant insertion and (post-operative) weightbearing may lead to higher reoperation rates. Level of evidence: Therapeutic level II.Orthopaedics, Trauma Surgery and Rehabilitatio