Development and testing of an experimental electromagnetic pump for liquid steel

An electromagnetic pump for liquid steel was built and subjected to laboratory testing. This pump was a flat linear induction pump whose flow channel was approximately 5/8 by 12 in. in cross section by 51 in. long. This pump was successfully operated with molten stainless steel in a demonstration in which a pressure development of about 9 psi was achieved. Possible areas of application of electromagnetic pumping to steelmaking operations and directions of further development are considered.     

Naphtha reforming kinetics—methane selectivity

The production of methane by steam-reforming of naphtha involves both rate controlling formation of carbon monoxide and hydrogen, followed by near equilibrium reactions of carbon monoxide with steam and hydrogen. In this paper a model is proposed for predicting the composition of the product gas for a single, isothermal/catalyst particle. For this system of both equilibrium and rate controlling reactions a new type of boundary condition is needed for the outer surface of the catalyst particle.The results (calculated for typical operating conditions of 400–530°C, 15–20 atm pressure, and a feed molal ratio of steam to naphtha to 6–25)The results presented for a single particle can be used with intrareactor conservation equations to predict the behavior of an integral reactor, for ex     

Modeling,control and simulation of a chain link STATCOM in EMTP-RV

This paper describes an alternative STATic synchronous COMpensator (STATCOM), by connecting a number of gate turn off (GTO) thyristor converters in series on the ac side of the system. Each GTO converter forms one ‘link’ of a 1-phase, full-bridge voltage–source-converter (VSC) and is referred to as a ‘Chain Link Converter’ (CLC). Each GTO of a chain link STATCOM (CLS), is switched ‘ON/OFF’ only once per cycle of the fundamental frequency by using a sinusoidal pulse width modulation (SPWM) technique. Approximate models of a 3-phase CLS using dq-transformation are derived to design two controllers for controlling reactive current and ac voltage to stabilize the system voltage at the point of common coupling (PCC). A novel technique, called the rotated gate signal pattern (RGSP), is used for balancing the voltages of the link dc capacitors. The performance investigation of the CLS system when used in a radial line is carried out under steady- and transient-state operating conditions by means of the simulation package; EMTP-RV and the results are presented.     

Quantifying particle segregation in sequential layers fabricated by additive manufacturing

Suspensions are used in Ceramic Stereolithography¹ (CerSLA) and other material processing methods. We applied Fast Fourier Transforms² (FFTs) in a novel way to signals generated from ceramic processing methods to address flaws resulting from sedimentation. We compared our analysis with traditional measures of sedimentation to show that this novel quantification of sedimentation is able to distinguish finer, subtler patterns of sedimentation. The explanation and application of FFTs and signal processing provided in this article enables the reader to use FFTs and signal processing in a broader way to further optimise and quantify materials processing methods.     

An analysis of axi-symmetric axial collapse of round tubes

Different size tubes of aluminium and mild steel were subjected to axial compression in an Instron machine. The tubes chosen were such that they collapsed in axi-symmetric concertina mode. Typical load-compression curves and deformed shapes of the collapsed tubes are presented. These reveal that the axi-symmetric folds formed in the deforming specimens extend both inside and outside of the line of original tube radius, and the ratio of the inside to outside fold lengths depends on the tube dimensions.

Considering the tube collapse mechanism as observed experimentally, an analysis is presented in an attempt to predict the mean collapse load and the post collapse load-compression curve. The computed values of the mean collapse load and the load-compression curve during a load oscillation, are presented and compared with the experiments, as well as with some existing theoretical results.     

Free and bound triacontanol in tea leaves

A direct gas chromatographic method of identification and determination of 1-triacontanol, a plant growth substance, in tea leaves is reported. Treatment of the tea leaves with calcium oxide releases more triacontanol, showing that the compound occurs also in a bound form in tea leaves.     

Enhanced sensitivity of lateral flow tests using a two-dimensional paper network format

Point-of-care diagnostic assays that are rapid, easy-to-use, and low-cost are needed for use in low-resource settings; the lateral flow test has become the standard bioassay format in such settings because it meets those criteria. However, for a number of analytes, conventional lateral flow tests lack the sensitivity needed to have clinical utility. To address this limitation, we are developing a paper network platform that extends the conventional lateral flow test to two dimensions. The two-dimensional structures allow incorporation of multistep processes for improved sensitivity, while still retaining the positive aspects of conventional lateral flow tests. Here we create an easy-to-use, signal-amplified immunoassay based on a modified commercial strip test for human chorionic gonadotropin, the hormone used to detect pregnancy, and demonstrate an improved limit of detection compared to a conventional lateral flow assay. These results highlight the potential of the paper network platform to enhance access to high-quality diagnostic capabilities in low-resource settings in the developed and developing worlds.     

Polymorphism of amyloid β peptide in different environments: implications for membrane insertion and pore formation

Amyloid-β (Aβ) peptides are thought to be involved in neurodegenerative diseases such as Alzheimer's disease and Down's syndrome. They form a large number of polymorphic structures, including heterogeneous ionic pores in membranes as well as different types of fibrillar and globular structures on surfaces and in solution. Understanding the origin of these structures and the factors that influence their occurrence is of great biomedical interest because of the possible relationship between structure and pathogenicity. Here, we use atomic force microscopy (AFM) and molecular dynamics (MD) simulations to demonstrate that at room temperature a truncated Aβ peptide which is generated in vivo and shown to be toxic in vitro forms fibrillar structures on hydrophobic graphite surfaces, but not on hydrophilic mica or lipid bilayers. Our results suggest that the toxic pores and fibrillar polymorphic organizations can be explained in terms of the U-shaped β-strand-turn-β-strand structural motif observed for full length Aβ and other amyloids, as well as the physicochemical properties at the interfaces. The interactions of the hydrophobic, truncated Aβ with its environment illustrate that the universal amyloid motif can provide a link between the pore and fibrillar structures and indicate that surfaces with different physicochemical properties can shift the polymorphic landscape toward other conformational states.