Physical Principles Governing Colloidal Particle Deposition at Low Reynold’s Number: Applications to Microbial Biofilms

Biofilms formed from the adhesion of microbes to a surface hold great relevance to public health and wastewater management. However, the physical principles underlying the attachment stage of biofilm formation, when individual microbes first come into contact with a substrate, are not well understood. Here I report on a model of colloidal particle attachment to a surface that incorporates the effects of diffusion, advection, gravity, and the hydrodynamic lift and drag forces experienced by polystyrene beads at low Reynold’s number. The simulation predicts attachment rates of 1.04x10^(-8)m/s, 0.73x10^(-8)m/s, and 1.29x10^(-8)m/s for beads of radius 0.25 µm, 0.55 µm, and 0.90 µm, respectively. Comparison to experimental data demonstrates that the calculated attachment rates approximate the observed rates, but that they tend to underestimate the experimental observations. The model could be further improved by the addition of other forces influencing particle deposition in a fluid environment

The use of twin screw extruders for feeding coal against pressures of up to 1500 PSI

Recent tests with a twin-screw, co-rotating extruder which was successfully used to convey and feed coal against pressures of up to 1500 psi are described. Intermeshing and self-wiping, co-rotating twin-screws give greatly improved conveying and pressure built-up capabilities and avoid hangup and eventual decomposition of coal particles in the screw flights. The conveying action of intermeshing, self-wiping, co-rotating extruder systems approaches that of a positive displacement pump. With this feature, it is possible to maintain very accurate control over all aspects of product conveyance in the extruder, i.e., intake, conveyance and pressure buildup

Highly sensitive multichannel spectrometer for subpicosecond spectroscopy in the midinfrared

A spectrometer system is presented for time-resolved probing in the midinfrared between 5 and 11 /tLmw ith a temporal resolution of better than 400 fs. Multichannel detection with HgCdTe detector arrays consisting of ten elements in combination with a high repetition rate permits one to record weak absorbance changes with an accuracy of 0.1 mOD

Evaluation of Hyperbaric Oxygen Therapy in the Treatment of Traumatic Brain Injuries

Traumatic brain injuries (TBIs) affect approximately 2.5 million people each year (Brain, 2014). The most current treatment options for TBIs include extensive long-term rehabilitation and therapy services, in which many only gain little improvement of their overall health (Traumatic, 2019). New trends in treating TBIs with hyperbaric oxygen therapy (HBOT) are emerging due to increased accessibility to hyperbaric oxygen chambers. The purpose of this research and systematic literature review is to evaluate the safety and efficacy of using HBOT to improve the treatment outcomes of TBIs. This review included the search of four databases including PubMed, Cochrane Review, Clinical Key, and DynaMed. The search included randomized control trials, systematic reviews, and meta-analyses that were published within the last 20 years. Several of the presented studies show evidence to support the use of HBOT in TBIs, however the majority of research suggests overall insufficient evidence to support the efficacy of HBOT in the treatment of TBIs. Several studies also address the concern for safety and side effects with the use of HBOT in treating TBIs, as individuals are exposed to increased pressures for long lengths of time. Ultimately, more research and clinical trials are needed in order to claim safety and efficacy in the use of HBOT for the treatment of TBIs