10,815 research outputs found
Comparative Analysis on Low Cost Continuous Carbon Fiber Polypropylene Composite Using Compression Molding and Automated Tape Placement
Carbon fiber reinforced plastics (CFRP) are widely used throughout the aerospace industry where a weight reduction remains the highest priority with less emphasis on cost. Textile grade carbon fiber (TCF) and other low cost carbon fiber (LCCF) alternatives have recently emerged for use in the automotive market where emissions regulations have pushed automotive manufacturers and research institutions to look for cost effective light weight materials. Fiber reinforced thermoplastics provide an effective solution that align with automotive design including low cost, high processing rates, high impact toughness, unlimited shelf life, and recyclability.
TCF and Zoltek_PX35 fibers are two LCCF aimed at the automotive, wind energy and commercial markets that are helping to push the cost of CF down to approximately $5 per lb. In combination with a hot melt thermoplastic pultrusion impregnation technique, an intermediate low cost composite tape can be produced that is shown to have good mechanical performance when consolidated through hot compression molding (CM). Automation is critical to the required rapid part production and process control within the automotive industry. Research was conducted into the manufacturing process parameters of LCCF composite tapes through in-situ consolidation with an automated tape placement (ATP) or automated fiber placement (AFP) robotic system. This research focuses on the manufacturing of low-cost continuous polypropylene composites and explores the mechanical and morphological properties associated with compression molding and automated tape placement
Was Expansionary Monetary Policy Feasible During the Great Contraction? An Examination of the Gold Standard Constraint
The recent consensus view, that the gold standard was the leading cause of the worldwide Great Depression 1929-33, stems from two propositions: (1) Under the gold standard, deflationary shocks were transmitted between countries and, (2) for most countries, continued adherence to gold prevented monetary authorities from offsetting banking panics and blocked their recoveries. In this paper we contend that the second proposition applies only to small open economies with limited gold reserves. This was not the case for the US, the largest country in the world, holding massive gold reserves. The US was not constrained from using expansionary policy to offset banking panics, deflation, and declining economic activity. Simulations, based on a model of a large open economy, indicate that expansionary open market operations by the Federal Reserve at two critical junctures (October 1930 to February 1931; September 1931 through January 1932) would have been successful in averting the banking panics that occurred, without endangering convertibility. Indeed had expansionary open market purchases been conducted in 1930, the contraction would not have led to the international crises that followed.
Money Stock Targeting, Base Drift and Price-Level Predictability: Lessons From the U.K. Experience
It is controversial whether money stock targeting without base drift (i.e. following a trend-stationary growth path) makes the price level more predictable in the presence of permanent shocks to money demand. Developing a procedure that does not run into the Lucas critique, and applying this procedure to the case of the U.K., the paper finds that the variance of the trend inflation rate in the U.K. would have been reduced by more than one half if the Bank of England had not allowed base drift.
Money Growth Variability and Money Supply Interdependence Under InterestRate Control: Some Evidence For Canada
Canada, like many countries, has recently experienced difficulties in achieving money growth stability and money supply independence. Based on the buffer-stock view of money-holding as well as the credit market approach to the money supply, this paper suggests that the problems have arisen from the Bank of Canada suse of an interestrate control mechanism.The paper argues that: (1) The short-run behavior of Canadian money grow this influenced by demand shifts in the Canadian credit market.(2)Movements in U.S. interest rates relative to the controlled Canadian interest rates are a key source of these shifts.The paper presents evidence on Canadian money supply and demand functions consistent with the foregoing explanation.
Development of high critical current density in multifilamentary round-wire Bi2Sr2CaCu2O8+x by strong overdoping
Bi2Sr2CaCu2O8+x is the only cuprate superconductor that can be made into a
round-wire conductor form with a high enough critical current density Jc for
applications. Here we show that the Jc(5 T,4.2 K) of such Ag-sheathed
filamentary wires can be doubled to more than 1.4x10^5 A/cm^2 by low
temperature oxygenation. Careful analysis shows that the improved performance
is associated with a 12 K reduction in transition temperature Tc to 80 K and a
significant enhancement in intergranular connectivity. In spite of the
macroscopically untextured nature of the wire, overdoping is highly effective
in producing high Jc values.Comment: 4 figure
An iterative procedure to obtain inverse response functions for thick-target correction of measured charged-particle spectra
A new method for correcting charged-particle spectra for thick target effects
is described. Starting with a trial function, inverse response functions are
found by an iterative procedure. The variances corresponding to the measured
spectrum are treated similiarly and in parallel. Oscillations of the solution
are avoided by rebinning the data to finer bins during a correction iteration
and back to the original or wider binning after each iteration. This
thick-target correction method has been used for data obtained with the MEDLEY
facility at the The Svedberg Laboratory, Uppsala, Sweden, and is here presented
in detail and demonstrated for two test cases.Comment: 14 pages, 8 figures, submitted to NIM
Feasibility of Photofrin II as a radiosensitizing agent in solid tumors - Preliminary results
Background: Photofrin II has been demonstrated to serve as a specific and selective radiosensitizing agent in in vitro and in vivo tumor models. We aimed to investigate the feasibility of a clinical application of Photofrin II. Material and Methods: 12 patients were included in the study (7 unresectable solid tumors of the pelvic region, 3 malignant gliomas, 1 recurrent oropharyngeal cancer, 1 recurrent adenocarcinoma of the sphenoid sinus). The dose of ionizing irradiation was 30-50.4 Gy; a boost irradiation of 14 Gy was added for the pelvic region. All patients were intravenously injected with 1 mg/kg Photofrin II 24 h prior to the commencement of radiotherapy. Magnetic resonance imaging (MRI) controls and in some cases positron emission tomography (PET) were performed in short intervals. The mean follow-up was 12.9 months. Results: No major adverse events were noted. Minor adverse events consisted of mild diarrhea, nausea and skin reactions. A complete remission was observed in 4/12 patients. A reduction in local tumor volume of > 45% was achieved in 4/12 patients. Stable disease was observed in 4/12 patients. 1 patient showed local disease progression after 5 months. Conclusion: The early follow-up results are encouraging regarding the feasibility of the application of Photofrin II as a radiosensitizing agent
Immune-Mediated Inflammation May Contribute to the Pathogenesis of Cardiovascular Disease in Mucopolysaccharidosis Type I.
BackgroundCardiovascular disease, a progressive manifestation of α-L-iduronidase deficiency or mucopolysaccharidosis type I, continues in patients both untreated and treated with hematopoietic stem cell transplantation or intravenous enzyme replacement. Few studies have examined the effects of α-L-iduronidase deficiency and subsequent glycosaminoglycan storage upon arterial gene expression to understand the pathogenesis of cardiovascular disease.MethodsGene expression in carotid artery, ascending, and descending aortas from four non-tolerized, non-enzyme treated 19 month-old mucopolysaccharidosis type I dogs was compared with expression in corresponding vascular segments from three normal, age-matched dogs. Data were analyzed using R and whole genome network correlation analysis, a bias-free method of categorizing expression level and significance into discrete modules. Genes were further categorized based on module-trait relationships. Expression of clusterin, a protein implicated in other etiologies of cardiovascular disease, was assessed in canine and murine mucopolysaccharidosis type I aortas via Western blot and in situ immunohistochemistry.ResultsGene families with more than two-fold, significant increased expression involved lysosomal function, proteasome function, and immune regulation. Significantly downregulated genes were related to cellular adhesion, cytoskeletal elements, and calcium regulation. Clusterin gene overexpression (9-fold) and protein overexpression (1.3 to 1.62-fold) was confirmed and located specifically in arterial plaques of mucopolysaccharidosis-affected dogs and mice.ConclusionsOverexpression of lysosomal and proteasomal-related genes are expected responses to cellular stress induced by lysosomal storage in mucopolysaccharidosis type I. Upregulation of immunity-related genes implicates the potential involvement of glycosaminoglycan-induced inflammation in the pathogenesis of mucopolysaccharidosis-related arterial disease, for which clusterin represents a potential biomarker
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