297 resultados para Brass
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Mode of access: Internet.
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Metalwork, Islamic, Abbasid; 11 39/64 in.x 6 11/16 in.; brass, cast, chased and hammered
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Chen Yanqing; H: 9 29/64 in.; leaded tin brass; lost-wax cast
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Col. diagrs. in pocket.
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Based on this new data, the Illinois EPA has requested that the Illinois Attorney General initiate legal action against H. Kramer relative to its contribution to a violation of the lead National Ambient Air Quality Standard.
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Based on this new data, the Illinois EPA has requested that the Illinois Attorney General initiate legal action against H. Kramer relative to its contribution to a violation of the lead National Ambient Air Quality Standard.
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Bound in bordered and panelled blind-tooled alum-tawed pigskin, with edges marbled in red, gold on red spine label, and brass and leather clasps (intact).
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Mode of access: Internet.
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Imperfect; wanting the volume entitled, "Paper, by Prof. Archer, Printing, by Joseph Hatton, etc."
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Leather bound boards with brass clasps.
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Title Varies: 1908-11, Transactions of the American Brass Founders' Association; 1912-16, Transactions of the American Institute of Metals; June 1917-Mar.1918, Journal of the American Institute of Metals
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The evolution of the pianoforte, by T.L. Southgate.- Our English songs, by W.H. Cummings.- The early English viols and their music, by H. Watson.- Madrigals, rounds, catches, glees, and part-songs, by E.M. Lee.- The recorder, flute, fife, and piccolo, by J. Finn.- Music in England in the year 1604, by Sir F. Bridge.- Our dances of bygone days, by A.S. Rose.- Masques and early operas, by A.H.D. Prendergast.- English opera after Purcell, by F.J. Sawyer.- Our cathedral composers and their works, by G.F. Huntley.- The single and double reed instruments, by D.J. Blaikley.- The water-organ of the ancients and the organ of to-day, by F.W. Galpin.- The regal and its successors: the harmonica, by T.L. Southgate.- The violin family and its music, by W.W. Cobbett.- The brass wind instruments, by J.E. Borland.- Some notes on early printed music, by A.H. Littleton.- Music of the country-side, by Sir E. Clarke.
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A number of magnesium alloys show promise as engine block materials. However, a critical issue for the automotive industry is corrosion of the engine block by the coolant and this could limit the use of magnesium engine blocks. This work assesses the corrosion performance of conventional magnesium alloy AZ91D and a recently developed engine block magnesium alloy AM-SC1 in several commercial coolants. Immersion testing, hydrogen evolution measurement, galvanic current monitoring and the standard ASTM D1384 test were employed to reveal the corrosion performance of the magnesium alloys subjected to the coolants. The results show that the tested commercial coolants are corrosive to the magnesium alloys in terms of general and galvanic corrosion. The two magnesium alloys exhibited slightly different corrosion resistance to the coolants with AZ91D being more corrosion resistant than AM-SC1. The corrosivity varied from coolant to coolant. Generally speaking. an oraganic-acid based long life coolant was less corrosive to the magnesium alloys than a traditional coolant. Among the studied commercial coolants. Toyota long, life coolant appeared to be the most promising one. In addition. it was found that potassium fluoride effectively inhibited corrosion of the magnesium alloys in the studied commercial coolants. Both general and galvanic corrosion rates were significantly decreased by addition of KF, and there were no evident side effects on the other engine block materials, such as copper, solder. brass. steel and aluminium alloys, in terms of their corrosion performance. The ASTM D 1384 test further confirmed these results and suggested that Toyota long life coolant with 1%wt KF addition is a promising coolant for magnesium engine blocks.
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Data fluctuation in multiple measurements of Laser Induced Breakdown Spectroscopy (LIBS) greatly affects the accuracy of quantitative analysis. A new LIBS quantitative analysis method based on the Robust Least Squares Support Vector Machine (RLS-SVM) regression model is proposed. The usual way to enhance the analysis accuracy is to improve the quality and consistency of the emission signal, such as by averaging the spectral signals or spectrum standardization over a number of laser shots. The proposed method focuses more on how to enhance the robustness of the quantitative analysis regression model. The proposed RLS-SVM regression model originates from the Weighted Least Squares Support Vector Machine (WLS-SVM) but has an improved segmented weighting function and residual error calculation according to the statistical distribution of measured spectral data. Through the improved segmented weighting function, the information on the spectral data in the normal distribution will be retained in the regression model while the information on the outliers will be restrained or removed. Copper elemental concentration analysis experiments of 16 certified standard brass samples were carried out. The average value of relative standard deviation obtained from the RLS-SVM model was 3.06% and the root mean square error was 1.537%. The experimental results showed that the proposed method achieved better prediction accuracy and better modeling robustness compared with the quantitative analysis methods based on Partial Least Squares (PLS) regression, standard Support Vector Machine (SVM) and WLS-SVM. It was also demonstrated that the improved weighting function had better comprehensive performance in model robustness and convergence speed, compared with the four known weighting functions.
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Backscatter communication is an emerging wireless technology that recently has gained an increase in attention from both academic and industry circles. The key innovation of the technology is the ability of ultra-low power devices to utilize nearby existing radio signals to communicate. As there is no need to generate their own energetic radio signal, the devices can benefit from a simple design, are very inexpensive and are extremely energy efficient compared with traditional wireless communication. These benefits have made backscatter communication a desirable candidate for distributed wireless sensor network applications with energy constraints.
The backscatter channel presents a unique set of challenges. Unlike a conventional one-way communication (in which the information source is also the energy source), the backscatter channel experiences strong self-interference and spread Doppler clutter that mask the information-bearing (modulated) signal scattered from the device. Both of these sources of interference arise from the scattering of the transmitted signal off of objects, both stationary and moving, in the environment. Additionally, the measurement of the location of the backscatter device is negatively affected by both the clutter and the modulation of the signal return.
This work proposes a channel coding framework for the backscatter channel consisting of a bi-static transmitter/receiver pair and a quasi-cooperative transponder. It proposes to use run-length limited coding to mitigate the background self-interference and spread-Doppler clutter with only a small decrease in communication rate. The proposed method applies to both binary phase-shift keying (BPSK) and quadrature-amplitude modulation (QAM) scheme and provides an increase in rate by up to a factor of two compared with previous methods.
Additionally, this work analyzes the use of frequency modulation and bi-phase waveform coding for the transmitted (interrogating) waveform for high precision range estimation of the transponder location. Compared to previous methods, optimal lower range sidelobes are achieved. Moreover, since both the transmitted (interrogating) waveform coding and transponder communication coding result in instantaneous phase modulation of the signal, cross-interference between localization and communication tasks exists. Phase discriminating algorithm is proposed to make it possible to separate the waveform coding from the communication coding, upon reception, and achieve localization with increased signal energy by up to 3 dB compared with previous reported results.
The joint communication-localization framework also enables a low-complexity receiver design because the same radio is used both for localization and communication.
Simulations comparing the performance of different codes corroborate the theoretical results and offer possible trade-off between information rate and clutter mitigation as well as a trade-off between choice of waveform-channel coding pairs. Experimental results from a brass-board microwave system in an indoor environment are also presented and discussed.