MIT Chemical Engineering – Department of Chemical Engineering at MIT
Eng., , vol. Materials Science and Engineering A, , vol. S. C. Lee and K. T. Kim, “A study on the Cap model for metal and ceramic powder under. Jabra X Red Bull. When extreme partnerships meet extreme engineering. Show me more. Previous. Elite Active 65t. Great for exercise; Up to 15 hours charge*. EC fans are generally recognised as being the latest thing in energy efficient air movement technology, but what is an EC fan and what makes it so special?.
Usually, our choice of model involves balancing the complexity needed to faithfully represent an actual experimental system and the simplicity required to make the simulation tractable. Fortunately, block copolymer phase behavior is believed to become universal in the high molecular-weight limit, which foregoes the need for detailed models. We illustrate how this universality can be used to make accurate predictions for a diblock copolymer melt from simulations using a simple lattice model. We conclude by discussing how this last obstacle could be overcome with field-theoretic simulations.
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Mark Matsen University of Waterloo A variety of approaches are available for generating biomaterial fibers from various precursor polymer solutions. Approaches such as wet-spinning, electrospinning, and extrusion have been exploited in the past to generate extremely long fibers ranging in diameter from tens of nanometers to hundreds of microns.
An alternative approach for manufacturing polymer fibers is to utilize a dry-spinning approach that generates fibers by balancing the cohesive forces within a highly-concentrated and highly-viscous polymer solution with the adhesive forces of this fluid with a solid substrate applicator. This approach can be used to generate a multitude of fibers that can be arranged on a collector to generate large scale fabrics from a variety of polymer precursor solutions. This presentation will describe the working principals underlying this approach to biomaterial fabric production, along with preliminary material characterization data.
Applications in the release of drugs and the templating of protein networks for directing cell growth will also be described. The versatility and potential of these materials for wound reconstruction, as well as in non-biomedical industrial applications will also be highlighted.
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Dr John Frampton Dalhousie University In its triple helical form, collagen assembles into fibrils with tensile properties comparable to the strongest man-made polymer materials. Structural characterization of collagen fibrils using X-ray scattering and electron microscopy led to a picture where long triple helices form a paracrystalline array with a distorted hexagonal radial packing, a slightly lower density of molecules in the fibril centre, and some moderate molecular tilt at the fibril surface.
Here I will present some recent single collagen fibril mechanical testing experiments that highlight both their rope-like and tube-like nature. I will also discuss how this rope-tube duality may be modulated by intermolecular crosslinks. Laurent Kreplak Dalhousie University In a first example, I will show how the integrated method used in our lab allows us to diagnose early dysregulation of the ECM materials properties in tumors.
In a second example, I will present 3D matrix-mimicking polymeric platforms we developed to control both COL and FN properties over macroscopic volumes. These platforms enable a better understanding of the critical link between protein structure and function, with the ultimate goal of controlling cellular functions through cell-matrix interactions. As such, they represent a new tool for biological research with many potential applications in basic research, medical diagnostics, and tissue engineering.
Delphine Gourdon Physics - University of Ottawa This talk describes the use of amphiphilic coiled-coil motifs in modular protein polymers as a strategy to achieve electrochemical gelation capabilities. Our de novo electrogelation protein is a telechelic, triblock design comprised of a central spider silk glue motif flanked by terminal pH-triggered coiled-coil domains. The coiled-coiled domains were designed to form intramolecular helix bundles below a sharply-defined pH-trigger point, while the pH-responsive spider silk glue sequence serves both as an anionic electrophoretic transport element at neutral and elevated pH and as a disordered linker chain between the associated helix bundles at reduced pH.
In an electrochemical cell, a solution of these telechelic proteins migrates toward the anode where the terminal coiled-coil domains are triggered to form coiled-coil assemblies that act as transient crosslinks for the e-gel state.
Upon cessation of the current, the coiled-coil domains denature gradually and the e-gel transforms back into a fluid solution of polypeptides in a fully reversible manner. This simplified triblock protein design mimics many of the characteristics of more complex electrogelation proteins, such as silk fibroin.
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We discuss experimental and computational studies the physical properties of this protein and the potential for biomedical applications of electrochemically triggered gelation. Harden University of Ottawa Hydrophobins can also undergo a structural rearrangement and oligomerize to form rodlets, which are an insoluble functional amyloid that coats fungal spores to act as a water repellent, facilitate dispersal into the air, and prevent immune recognition.
Rodlets are extremely durable and due to their biochemical properties they are a target for commercial application. To better understand what protein sequence characteristics determine hydrophobin properties, we are characterizing the structure and properties of diverse class IB hydrophobins from various fungal sources.
We have expressed hydrophobins in E. We then used nuclear magnetic resonance spectroscopy to characterize the high-resolution molecular structures of hydrophobins and are comparing their self-assembly properties with thioflavin-T fluorescence assays and atomic force microscopy. These experiments will form the basis of future mutagenesis experiments to develop new hydrophobins with desired properties. Dr David Langelaan Dalhousie University We measure the variation in the conformational free energy with respect to the end-to-end distance of the polymer, and from these functions we extract the free energy of the hairpin fold as well as the entropic force arising from interactions between the portions of the polymer that overlap along the channel.
We consider the scaling of the free energies with respect to varying the persistence length of the polymer and the channel dimensions for confinement in cylindrical, rectangular and triangular channels.
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We focus on polymer behaviour in both the classic Odijk and backfolded Odijk regimes. We find the scaling of the entropic force to be close to that predicted from a scaling argument that treats interactions between deflection segments at the second virial level. In addition, the measured hairpin fold free energy is consistent with that obtained directly from a recent theoretical calculation for cylindrical channels.
It is also consistent with values determined from measurements of the global persistence length of a polymer in the backfolded Odijk regime in recent simulation studies. The major conformational changes in these shape-shifting proteins are triggered by, for example, ligand binding, changes in pH, or — as in evolutionary processes — mutations.
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Using a coarse-grained model for protein folding with 7 atoms per amino acid and 3 amino acid types polar, hydrophobic and turn-typewe investigate the character of fold switching transitions.
We then apply a generalized-ensemble Monte Carlo algorithm to explore sequences that lie in the space between folds. At the border between folds, some sequences exhibit an ability to populate more than one fold. Such sequences are relatively rare, however, and fold changes are therefore typically accomplished in just a few mutational steps. We comment on potential evolutionary implications. Stefan Wallin Memorial University of Newfoundland Yet majority of its properties are poorly reproduced by the most commonly used models.
An ideal water model needs to accurately capture both structure and dynamics over a wide range of thermodynamic conditions. In fact, simply connect a potentiometer and you have infinitely variable speed control.
No triacs, no frequency inverters and no whining noises! An EC motor under speed control is virtually silent. EC is easy How does this affect energy efficiency? If you can tailor the fan speed to match the demand, the potential for energy saving is huge.The Fight for Sawmill
EC fans can also contribute to increasing the overall efficiency of an application. In a cooling system for example, keeping the refrigerant pressure constant rather than having it rise and fall as fans switch on and off has been found to reduce the load on the compressor resulting in even greater energy saving.
If two motors are producing the same output but one has a greater power input then you can be sure that the surplus energy is being dissipated as heat. If an application is designed to remove heat then it will have to do extra work just to remove the heat produced by the fan motor itself, so EC fans will improve the efficiency of the whole system.
EC AC motors are designed to operate at a certain point on their performance curve which coincides with their peak efficiency. Either side of this operating point, the efficiency can drop off considerably. EC motors on the other hand have an almost flat efficiency curve which varies relatively little across the speed range, a range which is not limited by synchronous speeds or as susceptible to voltage fluctuations as an AC motor. This makes the EC fan much more flexible in terms of being able to use the same product to match the performance requirements of different applications while still benefitting from increased efficiency.
The available range of AC input EC fans is expanding all of the time. There are axial and centrifugal fans, forward curved and backward curved, single inlet and double inlet, single phase and three phase and they are often directly interchangeable with their AC equivalents. EC offers the OEM more than just energy-efficiency.