Simulation Studies on Line Intersect Sampling of Residues Left After Cut-to-Length Logging

Upon carrying out logging, residues remain in the cutting area. Logging residues are an additional source of wood raw material for the production of fuel chips to be used in bioenergetics. In order to plan the logging residues collection and processing technology, it is necessary to gather information on the amount of this type of waste and its distribution within the cutting area.The article deals with the line intersect (LIS) method.The aim of this article was to assess the accuracy of the LIS method for quantifying logging residues after cut-to-length logging (CTL), uniformly distributed within the technology traffic lanes (strips) of width b on the cutting area of arbitrary shape S.The studies were conducted using computer simulations. In the models, logging residues are represented as clusters in the form of circles. The laws of distribution of the radius of the clusters and their position in the plot were determined by field measurements.In the simulations, clusters uniformly distributed along the X-axis and stripes on the Y-axis were considered. The samples of lines were the set of lines of different length and mutually perpendicular and parallel to the coordinate axes X, Y.In the simulations, four types of stripes were considered with a different angle to the Y-axis. Type 1 – angle = 0°, type 2 – angle = 15°, type 3 angle = 30°, type 4 – angle = 45°.It was determined through simulation that the estimated mean radius of the clusters is greater by 24% than the true mean radius.The LIS method formula is appropriate for estimating the amount of forest residues after CTL logging provided the true mean radius is taken. According to the results of simulation experiments, it was found that the results are in good agreement with the theoretical formulas if the location of the sample lines is mutually perpendicular and parallel to the coordinate axes X, Y of the area. Differences remain within the limits of 20% error.

Discussion on Determination Methods for Coefficient of Subgrade Reaction in Response Displacement Method

With the increasing focus on the earthquake resistant problems of subway engineering, the response displacement method is used in the seismic design of subway structures. The determination method for coefficient of subgrade reaction in seismic design of subway structures is very important. Four typical determination methods including test method, Lis method, MIDAS method and finite element method are introduced. Based on the values of coefficient of subgrade reaction from four methods, models of the response displacement method are used to obtain the bending moment of the subway structures. The advantages and disadvantages of four determination methods for coefficient of subgrade reaction are compared. The results show that the test method is the preferred one for designers, the tangential coefficient should be in a range of one to two third of the normal coefficient, and the internal force of subway structures can be obtained by the test method and modified by a correction factor that is 1.05.

VIDAS® Enzyme-Linked Immunofluorescent Assay for Detection of Listeria in Foods: Collaborative Study

The VIDAS LIS method and the traditional culture methods for detection of Listeria species in food were evaluated in a multilaboratory comparative study. The 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of Listeria. Results for each food and each contamination level with the VIDAS LIS method were as good as or better than those obtained with the traditional culture method. Of 1558 samples tested, 935 were positive: 839 by the VIDAS method and 809 by standard culture methods. Overall false negative rates were 10.3 and 13.5% for the VIDAS LIS and culture methods, respectively. The false positive rate for the VIDAS LIS assay was 1.4% based on 9 VIDAS LIS positive assays that did not confirm positive by isolation of Listeria. The agreement between the VIDAS LIS and culture methods for all samples tested was 86%.

Comparative Study of Colorimetric and Fully Automated Enzyme-Linked Immunoassay System for Rapid Screening of Listeria spp. in Foods

Two enzyme-linked immunoassay (ELISA) systems for rapid screening of Listeria spp. were compared for their use in analysis of spiked foods regulated by the U.S. Food and Drug Administration. The Tecra Listeria kit is a 48 h visual ELISA that detects Listeria spp. through colorimetry. It has been approved for first action by AOAC INTERNATIONAL.The Vitek immunodiagnostic assay system for Listeria (\i\D AS LIS) is a fully automated 48 h ELISA that detects Listeria spp. by immunofluorescence. Fifty-two food samples were artificially contaminated with high (11-42 colony-forming units [cfu]/25 g food) and low (2-8 cfu/25 g food) levels of L monocytogenes and screened by the 2 protocols. Unspiked samples were also assayed as negative controls. Six unspiked samples werefound positive for Listeria spp. by both methods: 3 were identified as L. monocytogenes and 3 as L. innocua by official methods. Both ELISA methods detectedall spiked samples. One unspiked sample was assayed positive by Tecra and negative by VIDAS LIS. No Listeria spp. were recovered when the sample was tested by the conventional method. Nointerference due to background fluorescence of food matrixes was observed in the VIDAS LIS method. Results suggest a modified VIDAS LIS preenrichment medium may be used in place of the VIDAS standard medium in the protocol.

Lanthaniden-Verschiebungen in der 1H- und 13C-Kernresonanzspektroskopie zur Konstitutionsermittlung von Thiadiazoloxiden / Lanthanide Induced Shifts in the 1H and 13C Nuclear Magnetic Resonance Spectroscopy for Structure Elucidations of Thiadiazole Oxides

A systematic investigation of the LIS-method for structure elucidations is performed on the basis of thermally generated monoxides of 1,2,3-thiadiazoles. A calculation process for the evaluation of lanthanide induced shifts according to the McConnell-Robertson equa-tion was developed. The program can be applied to underdetermined systems with fewer variables than chemically not equivalent X H plus 13 C nuclei. A quality criterium for the method is given by 4-phenyl-l,2,3-thiadiazole-3-oxid -wellknown by an X-ray analysis.