Laboratory sample of multipoint system to determine the arrangement of the explosion source

The article examines a laboratory sample of a maneuverable unit for slitting mountain meadows and pastures. Its design is adapted for work in a mountainous agricultural landscape with degraded soils having a slope of cultivated areas up to 15°. The study object is the structural, technological, operational, and agrotechnical parameters of the laboratory sample and the graphic-analytical rationalization of the working process of slitting on the slope. The technical tests of the laboratory model were carried out in Dargavs, RNO-Alania, at an altitude of 1540 meters above sea level with a slope steepness of up to 15°. The authors determined the indicators of test conditions and functional operation in accordance with GOST 33687-2016. The laboratory sample of a slitter (paraplow) mounted on the “Fenshaw-180” mini-tractor was adapted to a mountain zone with a reverse (obtuse) angle of penetration into the soil. The authors off er an optimal scheme for the arrangement of the working tools of the slitter. They determined the technology of its traveling along the slope and the design of the working tools providing the distance between the slits of 1000 ± 5 mm, the slitting depth of 200…220 mm, the slit width of 10…30 mm ± 5 mm. The considered sample of the unit for slitting mountain meadows and pastures will improve the moisture and air supply of the lower soil layers; reduce the degradation processes of slope areas, increase labor productivity, environmental sustainability, and grassland farming effi ciency.

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Considerations in the preparation of laboratory samples for the analysis of ochratoxin A in wheat

World Mycotoxin Journal ◽

10.3920/wmj2012.1393 ◽

2012 ◽

Vol 5 (2) ◽

pp. 107-116 ◽

Cited By ~ 13

Author(s):

S.A. Tittlemier ◽

M. Roscoe ◽

C. Kobialka ◽

R. Blagden

Keyword(s):

Ochratoxin A ◽

Whole Grain ◽

Laboratory Sample ◽

Test Portion ◽

Homogeneous Sample ◽

Ambient Temperatures ◽

Accuracy And Precision ◽

Relative Standard ◽

The Mean ◽

Ground Wheat

A process used to prepare the test portion of ground wheat from the whole grain laboratory sample for ochratoxin A (OTA) analysis using dry comminution with homogenisation and sub-sampling via a rotary sample divider was developed and evaluated. With respect to OTA content, the developed process produced a homogeneous sample of ground wheat from 10 kg of whole grain. Relative standard deviations of the mean OTA concentration for five naturally contaminated wheat samples processed using the developed method ranged from 9% to 19% over a relevant concentration range of 1.7 to 7.6 mg/kg. Additional studies demonstrated that OTA was stable in ground wheat with moisture content between 12 to 13% for at least a year when stored at ambient temperatures. Further examination of the developed comminution and dividing procedure demonstrated that higher concentrations were measured in smaller sized particles, indicating that the accuracy and precision of OTA analyses could be affected by the particle size of ground wheat.

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14. Laboratory sample

RILEM Technical Recommendations for the testing and use of construction materials ◽

10.1201/9781482271362-194 ◽

1994 ◽

pp. 777-777

Keyword(s):

Laboratory Sample

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A study into the scale effect on the strength properties of polymer composite materials

Nuclear Energy and Technology ◽

10.3897/nucet.5.35797 ◽

2019 ◽

Vol 5 (2) ◽

pp. 103-108

Author(s):

Valentina V. Kiryushina ◽

Yuliya Yu. Kovaleva ◽

Petr A. Stepanov ◽

Pavel V. Kovalenko

Keyword(s):

Composite Materials ◽

Polymer Composite ◽

Scale Effect ◽

Mechanical Characteristics ◽

Full Scale ◽

Sample Thickness ◽

Polymer Composite Materials ◽

Test Machine ◽

Test Results ◽

Laboratory Sample

Polymer composite materials (PCM) are used extensively and are viewed as candidates for application in various industries, including nuclear power. Despite a variety of methods and procedures employed to investigate the mechanical characteristics of PCMs, the use of the laboratory sample mechanical test results to design and model large-sized structures is not always fully correct and reasonable. In particular, one of the problems is concerned with taking into account the scale parameter effects on the PCM strength and elastic characteristics immediately in the product. The purpose of the study is to investigate the scale effects on the mechanical characteristics of glass reinforced plastics using phenolformaldehyde and silicon-organic binders and a fabric quartz filler. Samples of four different standard sizes under GOST 25604-82 and GOST 4648-2014 were tested for three-point bending using an LFM-100 test machine to estimate the scale effect. The thicknesses of the model samples were chosen with regard for the wall thicknesses of full-scale products under development or manufactured commercially and the test machine features, and varied in the limits of 1.6 to 7.5 mm. The tests showed that strength decreased as the sample thickness was increased to 3 mm and more both at room and elevated (200 to 500 °C) temperatures, which can be described by an exponential function based on the Weibull statistical model. The values of the Weibull modulus that characterizes the extent of the scale effect on the strength of the tested materials were 4.6 to 6.7. The average bend strength in the sample thickness range of 3 mm and less does not vary notably or tends to increase slightly as the thickness is increased. This fact makes it possible to conclude that estimation of allowable stresses in a thin-wall product requires the use of test results for samples with a thickness that is equal to the product wall thickness since standard samples may yield overestimated allowable stress values and lead, accordingly, to incorrect calculations of the strength factor. The results obtained shall be taken into account when defining the allowable levels of operation for full-scale products and structures of polymer composites based on the laboratory sample strength data as well as when estimating their robustness as a characteristic of the product’s fail-safe operation.

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Automated Fiber-Optic System for Monitoring the Stability of the Pit Quarry Mass and Dumps

Occupational Safety in Industry ◽

10.24000/0409-2961-2021-4-19-26 ◽

2021 ◽

pp. 19-26

Author(s):

А.D. Меkhtiyev ◽

◽

E.G. Neshina ◽

P.Sh. Madi ◽

D.A. Gorokhov ◽

...

Keyword(s):

Rock Mass ◽

Optical Fiber ◽

Optical Fibers ◽

Fiber Optic ◽

Light Wave ◽

Single Mode ◽

Fiber Optic Sensors ◽

Fiber Optic Sensor ◽

Laboratory Sample ◽

Single Mode Optical Fiber

This article ls with the issues related to the development of a system for monitoring the deformation and displacement of the rock mass leading to the collapse of the quarry sides. Monitoring system uses point-to-point fiber-optic sensors. Fiber-optic sensors and control cables of the communication line are made based on the single mode optical fibers, which allows to measure with high accuracy the deformations and displacements of the rock mass at a distance of 30-50 km. To create fiber-optic pressure sensors, an optical fiber of the ITU-T G. 652.D standard is used. Laboratory sample is developed concerning the point fiber-optic sensor made based on the two-arm Mach-Zender interferometer using a single mode optical fiber for monitoring strain (displacements) with a change in the sensitivity and a reduced influence of temperature interference leading to zero drift. The article presents a mathematical apparatus for calculating the intensity of radiation of a light wave passing through an optical fiber with and without mechanical stress. A laboratory sample of single mode optical fibers based on the Mach-Zender interferometer showed a fairly high linearity and accuracy in the measurement and can be used to control the strain of the mass after appropriate refinement of its design. Mathematical expressions are also given for determining the intensity of the light wave when the distance between the fixing points of a single mode optical fiber changes depending on the change in the external temperature. A diagram for measuring strain using a point fiber-optic strain sensor is developed. Hardware and software package is developed, which can be used to perform a number of settings of measuring channels. The work is aimed at solving the production problems of the Kenzhem quarry of AK Altynalmas JSC.

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