Direct Observation of the Tumbling of OSB Strands in an Industrial Scale Coil Blender

A series of experiments were carried out in an 11- by 35-ft industrial scale rotary drum blender in which a small amount of OSB furnish was placed, and the motions of strands were recorded with a video camera at various drum rotation speeds. As the blender rotated, the strands were lifted up by the flights—short fins inside and running the length of the blender—until they sloughed off and fell to the bottom of the drum. At low rotation speeds, the strands fell a short distance as they sloughed from flight to flight; at intermediate speeds, the strands fell across the diameter of the drum; and at higher speeds the freefall distance decreased again and was similar to the low speed case. The distance through which the strands fell with each revolution was shown theoretically to be inversely proportional to drum speed. The residence time of the stands in the blender set at a tilt angle of 3° was measured for five drum speeds and found to be directly proportional to drum speed. It was concluded that the speed that produces the most uniform dispersion of resin on the strands is a compromise between that which is high enough to ensure that the strands will slough from the flights many times, but low enough to provide sufficient time for the strand to twirl and flip and become coated with resin. The potential advantages of using specially shaped atomizer booms to direct strand flow to maximize the uniformity of the resin dispersion over the strand surface is also discussed

The Verkhovna Rada Should Establish Courts of Limited Jurisdiction with Both Civil and Criminal Jurisdiction as Part of Ukrainian Judicial Reform

This article offers suggestions to the Ukraine Parliament on how to create an effective small claims court that addresses misdemeanor criminal cases, preliminary hearings and limited damages civil jurisdiction. The paper is one of nine papers presented by American judges offering prototype blueprints for the three basic levels of courts in Ukraine. Three judges addressed appeals, three judges addressed general jurisdiction courts, and this paper was one of the three papers addressing limited jurisdiction courts. The papers were written at the request of the National Judicial College and USAid.gov to guide Ukraine’s efforts to strengthen their judiciary. The author is a Tennessee municipal judge and a Native American appellate jurist

Allostery in Oligomeric Receptor Models

We show how equilibrium binding curves of receptor homodimers can be expressed as rational polynomial functions of the equilibrium binding curves of the constituent monomers, without approximation and without assuming independence of receptor monomers. Using a distinguished spanning tree construction for reduced graph powers, the method properly accounts for thermodynamic constraints and allosteric interactions between receptor monomers (i.e. conformational coupling). The method is completely general; it begins with an arbitrary undirected graph representing the topology of a monomer state-transition diagram and ends with an algebraic expression for the equilibrium binding curve of a receptor oligomer composed of two or more identical and indistinguishable monomers. Several specific examples are analysed, including guanine nucleotide-binding protein-coupled receptor dimers and tetramers composed of multiple ‘ternary complex’ monomers

Regenerative Ionic Currents and Bistability

What every neuroscientist should know about the mathematical modeling of excitable cells. Combining empirical physiology and nonlinear dynamics, this text provides an introduction to the simulation and modeling of dynamic phenomena in cell biology and neuroscience. It introduces mathematical modeling techniques alongside cellular electrophysiology. Topics include membrane transport and diffusion, the biophysics of excitable membranes, the gating of voltage and ligand-gated ion channels, intracellular calcium signalling, and electrical bursting in neurons and other excitable cell types. It introduces mathematical modeling techniques such as ordinary differential equations, phase plane, and bifurcation analysis of single-compartment neuron models. With analytical and computational problem sets, this book is suitable for life sciences majors, in biology to neuroscience, with one year of calculus, as well as graduate students looking for a primer on membrane excitability and calcium signalling.https://scholarworks.wm.edu/asbookchapters/1133/thumbnail.jp

Emergence of switch-like behavior in a large family of simple biochemical networks

Bistability plays a central role in the gene regulatory networks (GRNs) controlling many essential biological functions, including cellular differentiation and cell cycle control. However, establishing the network topologies that can exhibit bistability remains a challenge, in part due to the exceedingly large variety of GRNs that exist for even a small number of components. We begin to address this problem by employing chemical reaction network theory in a comprehensive in silico survey to determine the capacity for bistability of more than 40,000 simple networks that can be formed by two transcription factor-coding genes and their associated proteins (assuming only the most elementary biochemical processes). We find that there exist reaction rate constants leading to bistability in ~90% of these GRN models, including several circuits that do not contain any of the TF cooperativity commonly associated with bistable systems, and the majority of which could only be identified as bistable through an original subnetwork-based analysis. A topological sorting of the two-gene family of networks based on the presence or absence of biochemical reactions reveals eleven minimal bistable networks (i.e., bistable networks that do not contain within them a smaller bistable subnetwork). The large number of previously unknown bistable network topologies suggests that the capacity for switch-like behavior in GRNs arises with relative ease and is not easily lost through network evolution. To highlight the relevance of the systematic application of CRNT to bistable network identification in real biological systems, we integrated publicly available protein-protein interaction, protein-DNA interaction, and gene expression data from Saccharomyces cerevisiae, and identified several GRNs predicted to behave in a bistable fashion.Comment: accepted to PLoS Computational Biolog

Technical Note: Effects of Nanoclay Addition to Phenol-Formaldehyde Resin on the Permeability of Oriented Strand Lumber

This note examined the effects of adding nanoclays to phenol-formaldehyde resin during the manufacture of oriented strand lumber (OSL) on its in-plane permeability. The panels were made from mountain pine beetle (MPB) attacked lodgepole pine (Pinus contorta) strands. Three different montmorillonite nanoclays were mixed with the PF resin: Na+, hydrophobic organics modified 10A, and hydrophilic organics modified 30B. None of the nanoclays changed the permeability of OSL significantly. The MPB-OSL had higher in-plane permeability than those conventionally made from aspen, which indicated that the pressing time could be shorter for MPB-OSL compared with OSL made from MPB-free strands

In-Plane Permeability of Oriented Strand Lumber, Part I: The Effects of Mat Density and Flow Direction

The in-plane permeability was measured for thick, unidirectional oriented strand lumber made from aspen (Populus tremuloides) strands and pressed to five different densities. The press cycle was such that the vertical density profile of the panels was uniform. Specimens were cut from the boards and sealed inside a specially designed specimen holder; this jig was connected to a permeability measurement apparatus and in-plane permeability measured parallel, perpendicular, and 45° to the strand orientation. Permeability decreased markedly with increasing board density. The highest permeability was in the strand alignment direction and lowest perpendicular to it. The permeability in the 45° direction fell between those in parallel and perpendicular to strand alignment. A polynomial equation was fit to the results of each direction with r2 of 0.938 and 0.993. The in-plane distribution of permeability as a function of flow direction was obtained and its vector diagram was lenticular in shape