Enhanced vision for adverse weather aircraft landing

Landing in poor weather is a crucial problem for the air transportation system of the future. To aid the pilots for these conditions several solutions have been suggested and/or implemented including instrument landing system(ILS) and microwave landing system(MLS) that put the responsibility of the landing to a large extent in the hands of the airport facilities. These systems even though useful are not available due to their high costs except in few major metropolitan airports. This shortcoming has generated interest in providing all weather capabilities not on the landing facility but on the vehicle itself. The Synthetic Vision System Technology Demonstration sponsored by the United States Federal Aviation Administration(FAA) and the US Air Force represents an effort to respond to the above needs[1,2]. In this paper we present a summary of a typical synthetic vision system. This system consists of a scanning 35GHz radar a scanning antenna, a signal/image processor and a head up display(HUD). The pilot is presented a final perspective image of the scene sensed by the radar with associated flight guidance symbology. This systems is implemented in real time hardware and has been under going tower and flight testing under a variety of weather conditions since early 1992.     

Predicting recrystallized grain size in friction stir processed 304L stainless steel

A major dilemma faced in the nuclear industry is repair of stainless steel reactor components that have been exposed to neutron irradiation. When conventional fusion welding is used for repair, intergranular cracks develop in the heat-affected zone(HAZ). Friction stir processing(FSP), which operates at much lower peak temperatures than fusion welding, was studied as a crack repair method for irradiated 304 L stainless steel. A numerical simulation of the FSP process in 304 L was developed to predict temperatures and recrystallized grain size in the stir zone. The model employed an Eulerian finite element approach,where flow stresses for a large range of strain rates and temperatures inherent in FSP were used as input. Temperature predictions in three locations near the stir zone were accurate to within 4%, while prediction of welding power was accurate to within 5% of experimental measurements. The predicted recrystallized grain sizes ranged from 7.6 to 10.6 μm, while the experimentally measured grains sizes in the same locations ranged from 6.0 to 7.6 μm. The maximum error in predicted recrystallized grain size was about 39%, but the associated stir zone hardness from the predicted grain sizes was only different from the experiment by about 10%.     

A detailed investigation of the microwave assisted phenylphosphonic acid modification of P25 TiO2

The microwave assisted reaction between P25 titanium dioxide (TiO₂) and phenylphosphonic acid (PPA) is explored thoroughly and the influence of the reaction conditions on the grafting mechanism and formed products is presented. While the surface grafting is observed at low temperatures and water free conditions, the formation of titaniumphosphonate is favored in water and high reaction temperatures. For the first time the correlation between the amorphous TiO₂ phase and the formation of titaniumphenylphosphonate is reported. Materials are fully characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), solid-state ³¹P Nuclear Magnetic Resonance (³¹P NMR) spectroscopy, energy dispersive X-ray (EDX) spectroscopy and transmission electron microscopy (TEM).     

Growth and survival of foodborne pathogens in beer

This work aimed to assess the growth and survival of four foodborne pathogens (Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes, and Staphylococcus aureus) in beer. The effects of ethanol, pH, and storage temperature were investigated for the gram-negative pathogens (E. coli O157:H7 and Salmonella Typhimurium), whereas the presence of hops ensured that the gram-positive pathogens (L. monocytogenes and S. aureus) were rapidly inactivated in alcohol-free beer. The pathogens E. coli O157:H7 and Salmonella Typhimurium could not grow in the mid-strength or full-strength beers, although they could survive for more than 30 days in the mid-strength beer when held at 4°C. These pathogens grew rapidly in the alcohol-free beer; however, growth was prevented when the pH of the alcohol-free beer was lowered from the "as received" value of 4.3 to 4.0. Pathogen survival in all beers was prolonged at lowered storage temperatures.     

优化环锭纺纱换管工艺的新系统

对现代的、操作优化的和几乎完全自动化的环锭纺纱来说,一种最少断头且无故障的换管工艺是绝对必要的.为达此目的,在落纱操作时必须将纱尾固定在锭子上,这样纱线就能正确地在满管和锭子之间断开,另一方面,来自牵伸区的纱线能安全保留在钢丝圈里.     

Quantitative Standards of 4-O-Acetyl- and 9-O-Acetyl-N-Acetylneuraminic Acid for the Analysis of Plasma and Serum

N-Acetylneuraminic acid (sialic acid, Neu5Ac) is one of a large, diverse family of nine-carbon monosaccharides that play roles in many biological functions such as immune response. Neu5Ac has previously been identified as a potential biomarker for the presence and pathogenesis of cardiovascular disease (CVD), diabetes and cancer. More recent research has highlighted acetylated sialic acid derivatives, specifically Neu5,9Ac₂, as biomarkers for oral and breast cancers, but advances in analysis have been hampered due to a lack of commercially available quantitative standards. We report here the synthesis of 9-O- and 4-O-acetylated sialic acids (Neu5,9Ac₂ and Neu4,5Ac₂) with optimisation of previously reported synthetic routes. Neu5,9Ac₂ was synthesised in 1 step in 68 % yield. Neu4,5Ac₂ was synthesised in 4 steps in 39 % overall yield. Synthesis was followed by analysis of these standards via quantitative NMR (qNMR) spectroscopy. Their utilisation for the identification and quantification of specific acetylated sialic acid derivatives in biological samples is also demonstrated.     

Analysis of defect mechanisms in nonstoichiometric ceria–zirconia by the microwave cavity perturbation method

In this microwave study, the defect chemistry of ceria–zirconia solid solutions (CZO, Ce_1−yZr_yO_2−δ) was investigated at high temperatures by a resonant microwave method. Specifically, the effects of temperature and Zr content on the dielectric properties and defect chemistry mechanisms in CZO were analyzed. Experiments were performed on a series of different CZO powders (y = 0.2, 0.33, 0.50, 0.67). Measurements at 600°C and different oxygen partial pressures (p_O2 = 10⁻²⁶–0.2 bar) confirm a dominant n-type conduction of small-polarons in CZO due to the preferred formation of oxygen vacancies, which is also supported by a multimodal analysis. Polarization losses were found to be negligible in the GHz range. Furthermore, an increased relative permittivity was observed in CZO, which correlates with the concentration of oxygen vacancies in CZO. Our microwave study is the first to provide a comprehensive data set for the dielectric properties of CZO powder sample in a wide range of different conditions. In addition, the connection of dielectric properties to CZO defect chemistry mechanisms is presented. The results are in good agreement with findings in the literature and may contribute to a better understanding of microwave-based state diagnosis of CZO-based materials, as it discussed for three-way catalysts.