Usability of abattoir-acquired pig eyes for refractive excimer laser research

The purpose of this study was to elucidate, under which conditions abattoir-acquired pig eyes are suitable for refractive excimer laser experiments. Porcine eyes from tunnel-scalded (n = 5) and tank-scalded (n = 10) pigs were compared to unscalded eyes (n = 5) and to eyes scalded in the laboratory (n = 5). The corneal epithelium was removed before an excimer laser was used to perform a − 8.0 D photoablation. Corneal thickness was measured by optical coherence topography before and after photoablation. The ablation depth was determined with a contour measuring station, the morphology of the ablated areas was characterized by scanning electron microscopy and white-light profilometry. The scalded eyes showed an increase in corneal swelling which gained statistical significance in tank-scalded eyes showing a wedge-shaped opaque stromal lesion in the nasal corneal quadrant. A measurable deterioration of photoablation was only found in tank-scalded eyes that exhibited the opaque lesion. Ablated area morphology was smooth and regular in the unscalded and tunnel-scalded eyes. The tank-scalded eyes showed conspicuous wrinkles. While unscalded eyes should always be preferred for excimer laser laboratory experiments, the data suggest that the use of tunnel-scalded eyes may also be acceptable and should be chosen over tank-scalded eyes.

EXPERIMENTAL DETERMINATION OF STRESS PARAMETERS IN THE MINING FIELD

The experience of measuring the stress state of the rock mass at the Tashtagol iron ore deposit and the result of stresses acting in the induced field in the vicinity of 10 orts at a depth of 800 m from the daily surface (horizon -350) is presented using the method of measuring hydraulic fracturing. Stress concentration zones around the mine are determined at the measuring station.

Analysis of Bulb Turbine Hydrofoil Cavitation

The influence of a bulb runner blade hydrofoil shape on flow characteristics around the blade was studied. Experimental work was performed on a bulb turbine measuring station and a single hydrofoil in a cavitating tunnel. In the cavitation tunnel, flow visualization was performed on the hydrofoil’s suction side. Cavitation structures were observed for several cavitation numbers. Cavitation was less intense on the modified hydrofoil than on the original hydrofoil, delaying the cavitation onset by several tenths in cavitation number. The results of the visualization in the cavitation tunnel show that modifying the existing hydrofoil design parameters played a key role in reducing the cavitation inception and development, as well as the size of the cavitation structures. A regression model was produced for cavitation cloud length. The results of the regression model show that cavitation length is dependent on Reynolds’s number and the cavitation number. The coefficients of determination for both the existing and modified hydrofoils were reasonably high, with R2 values above 0.95. The results of the cavitation length regression model also confirm that the modified hydrofoil exhibits improved the cavitation properties.

Laboratory tests results of a measuring station for plate bearing tests of road structures

An article devoted to the development of the latest equipment for testing road structures during the diagnostics of roads both in the process of repair and construction, and in the process of operation. A measuring station for stamp tests of road structures and their layers has been developed, which unites the test equipment into a single automated complex mounted on the base car. This eliminates the need for manual labor of the operator, increases productivity and accuracy of tests, provides the ability to perform multiple loads. At the same time, any truck or road vehicle can be used to create the load. A measuring unit with special software installed on it is used for registration and processing of measurement results. The results of laboratory tests of the measuring station, which were carried out in the laboratory of the department of metrological support of measurements of geometric quantities of SE «Ukrmetrteststandard» are highlighted. The obtained results indicate that the values of measuring force, absolute error and range of measurements of the station of movement of the station meet the regulatory requirements.

GUM’s Rockwell hardness standard machines after modernization

This article describes two twin deadweight-type Rockwell hardness standard machines (HSMs – HSM-S02 and HSM-NT) of GUM after modernization. A new control system for the station with database, a hydraulic pump, a displacement measuring system and an application enabling the operator to operate the measuring station are described. The adjustment process of the HSM-S02 with entering automatic compensation (correction) enabling the improvement of the measured result in real time is presented.

Information system for scientific study of the micrometeorology of karst caves – Case of Postojnska jama cave, Slovenija

The paper presents the construction and operation of a cave information system on the example of the Postojnska jama cave. It thoroughly describes the construction of the basic modules of the cave information system, such as an automatic cave measuring station with sensors for measuring air temperature, air flow and CO2 concentration, and a central unit for collecting, saving, processing and displaying data. The system provides quality automatic measurements for the scientific study of the micrometeorology of karst caves. Its construction is based on good practices stemming from many years of experience in taking measurements in the external atmosphere and in karst caves. The paper is rich and comprehensive guideline for automatic cave measuring system construction for scientific and tourist management purposes.