Contraction Based on Sentential Selection

The properties of full meet contraction are investigated, andit is shown to be a useful building-block in the constructionof composite contraction operators. This is followed by a detailedinvestigation of specified meet contraction, i.e. the operation÷ such that K ÷ p = K f(p), where is full meetcontraction and f is a function from sentences to sentences.A number of realistic examples of belief contraction are discussed,and it is shown how the properties of contraction differ accordingto how the sentence to be contracted is situated in the structureof the belief state. Some plausible properties of f are proposed,and it is shown how they correspond to properties of the contractionoperator.     

Slepian simulation of distributions of plastic displacements of earthquake excited shear frames with a large number of stories

The object of this study is a stationary Gaussian white noise excited plane multistory shear frame with a large number of rigid traverses. All the traverse-connecting columns have finite symmetrical yield limits except the columns in one or more of the bottom floors. The columns behave linearly elastic within the yield limits and ideally plastic outside these without accumulating eigenstresses. Within the elastic domain, the frame is modeled as a linearly damped oscillator. The white noise excitation acts on the mass of the first floor making the movement of the elastic bottom floors simulate a ground motion that interacts with the structure above the bottom floors. As in a recent work by the authors, the paper is about application of the so-called Slepian model simulation, but in this paper supplemented by a simplification principle that allows a manageable calculation for the considered type of elasto-plastic oscillator also when it has a large number of elasto-plastic columns.     

The XT-tube extractor: a hollow fiber-based supported liquid membrane extractor for bioanalytical sample preparation

A new supported liquid membrane extractor for bioanalytical sample preparation is presented. The extractor consists of a polypropylene hollow fiber mounted inside a PTFE tube by means of a cross-connector and a tee-connector. All parts are commercially available, inexpensive, and easily assembled. An organic solvent in the pores of the fiber forms a liquid membrane that separates the sample, which is pumped along the outside of the fiber, from the acceptor phase, which is pumped inside. The length of the hollow fiber may easily be varied to meet different demands on extractive surface and extract volumes. To test the system, the strongly acidic plasticizer/flame retardant metabolite diphenyl phosphate ester (DPhP), with a pKa value of 0.26, was extracted from urine. DPhP was protonated using 4 M hydrochloric acid and extracted into an acceptor phase at pH 9. Thirty extractions were made with the same liquid membrane without any decrease in extraction efficiency and with a relative standard deviation <7%. An analyte concentration enrichment of 5-10 times was achieved in the extraction step, giving a limit of detection (S/N = 3) of 0.014 microg/mL with LC/ESI-MS and 0.18 microg/mL with CE-UV. The effects on extraction efficiency using different sample pH, organic solvents, sample flow rates, and lengths of the fiber were evaluated.     

Simulation of sea surface wave influence on small target detection with airborne laser depth sounding

A theoretical model for simulation of airborne depth-sounding lidar is presented with the purpose of analyzing the influence from water surface waves on the ability to detect 1-m3 targets placed on the sea bottom. Although water clarity is the main limitation, sea surface waves can significantly affect the detectability. The detection probability for a target at a 9-m depth can be above 90% at 1-m/s wind and below 80% at 6-m/s wind for the same water clarity. The simulation model contains both numerical and analytical components. Simulated data are compared with measured data and give realistic results for bottom depths between 3 and 10 m.     

技术哲学视阈中的风险和安全

对风险和安全哲学进行了概述,对与之相关的风险、不确定性、安全性和预防等核心概念进行了界定,特别强调了风险和不确定性的区分,并且论述了这种区分的重要性.以对科学中不确定性信息的处理的讨论为基础,论述了在科学的不确定性情形下进行决策的问题,澄清了预防原则的作用.探讨了如何实施安全工程的主要方法,强调了诸如内在安全性、安全因素和多重安全阻抗等安全原则的作用.在此基础上,指出风险性和安全性问题是技术哲学研究中的重要领域.     

Methodology for detection of carbon monoxide in hot, humid media by telecommunication distributed feedback laser-based tunable diode laser absorption spectrometry

Detection of carbon monoxide (CO) in combustion gases by tunable diode laser spectrometry is often hampered by spectral interferences from H2O and CO2. A methodology for assessment of CO in hot, humid media using telecommunication distributed feedback lasers is presented. By addressing the R14 line at 6395.4 cm(-1), and by using a dual-species-fitting technique that incorporates the fitting of both a previously measured water background reference spectrum and a 2f-wavelength modulation lineshape function, percent-level concentrations of CO can be detected in media with tens of percent of water (c(H2O)≤40%) at T≤1000?°C with an accuracy of a few percent by the use of a single reference water spectrum for background correction.     

Effect of organic manure and chemical fertilizer on nitrogen uptake and nitrate leaching in a Eum-orthic anthrosols profile

Distribution and accumulation of NO₃-N down to 4 m depth in the soil profile of a long term fertilization experiment with organic manure and N and P chemical fertilizer were studied after 12 years, wheat and corn were planted in each year. The apparent N recovery decreased with increased N and P fertilizer. NO₃-N was mainly accumulated in 0-1.2 m depth of the soil profile with a maximum of 34 mg N kg-¹ for the treatment with 120 kg N and 26 kg P per hectare, a secondary maximum of 7.2 mg N kg-¹ was found at 3.2 m depth in the same treatment. NO₃-N accumulation in the soil profile was minimized in the trials with highest manure application. Nitrogen that was not recovered was leached as NO₃-N deeper than 4 m depth, was immobilized in the profile or was lost by denitrification. This revised version was published online in August 2006 with corrections to the Cover Date.     

Technological challenges for hydrocarbon production in the Barents Sea

Technological challenges for hydrocarbon production in the Barents Sea relate mainly to the climatic conditions (ice and icebergs), to the relatively deep water of the area, and to the distance to the market for transportation of gas. It is suggested that environmental conditions must be carefully mapped over a sufficiently long period to get reliable statistics for the area.Published in Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 29–34, August, 1994.