Dalibor Kuhinek

Measurement Uncertainty in Testing of Uniaxial Compressive Strength and Deformability of Rock Samples

Measurement Uncertainty in Testing of Uniaxial Compressive Strength and Deformability of Rock Samples This paper describes instrumental measurement uncertainties and their influence on the result obtained from determination of rock sample uniaxial compressive strength and deformability. The interdependence of uncertainty contribution is analyzed and guides for improving measurement uncertainty are given. The achieved uncertainties are compared to typical uncertainties in the determination of concrete and metallic material compressive strength and deformability.

No-Load analysis of permanent magnet machines with bread-loaf magnets and fractional-slot winding using conformal mapping and magnetic equivalent circuits

The paper describes a method for no-load analysis of surface permanent magnet motors with bread-loaf magnets using a model based on conformal mapping and magnetic equivalent circuits which takes iron core saturation into account. The proposed method has been utilized for calculation of air-gap flux density distribution, back-EMF and cogging torque waveforms and has been implemented and evaluated on the example of 33 slot / 8 pole motor. The results show good agreement with those obtained by using finite element method and measurements.

Development of Virtual Instrument for Uniaxial Compression Testing of Rock Samples

Development of Virtual Instrument for Uniaxial Compression Testing of Rock Samples This paper presents the virtual instrument for measurement and determination of uniaxial compression strength and rock sample deformability. It analyzes properties and limitations of several implemented virtual instruments. Furthermore, comparison of implemented virtual instrument properties is presented.

Enhanced Vibrating Wire Strain Sensor

Vibrating wire sensors are used for strain measurement. Sensing is based in frequency change when tension of wire changes. Here are considered other possibilities of vibrating wire strain gauge implementations and their properties. It includes change in frequency with change in length and some implementations with sliding contact. Last implementation consists of firm beam and short segment of wire which allows better sensitivity of sensor giving substantially larger increase of frequency for small increase in strain.

On-Load Analysis of Saturated Surface Permanent Magnet Machines Using Conformal Mapping and Magnetic Equivalent Circuits

This paper presents an iterative method based on conformal mapping and magnetic equivalent circuits for on-load analysis of saturated surface permanent magnet machines with integer slot and fractional slot windings. Magnetic saturation is taken into account by defining additional point wires in the stator slots and interpolar region between the magnets. The added point wires create magnetomotive force equal to the magnetic voltage drops across iron core flux tubes that are calculated using magnetic equivalent circuit. An improved stator tooth model has been introduced that enables more accurate field calculations for tooth geometries with highly saturated tooth tips. The model also takes into account variation of permanent magnet magnetization due to external magnetic field. The proposed method has been implemented on a saturated 12 slot, 10 pole surface permanent magnet machine with nonoverlapping concentrated winding and shows a very good agreement with finite element calculations in terms of flux density, back electromotive force, and torque waveforms as well as <inline-formula><tex-math notation=LaTeX>

IMPACT OF ROCK HARDNESS ON FRAGMENTATION BY HYDRAULIC HAMMER AND CRUSHING IN JAW CRUSHER

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Simulation of the chain saw cutting process with a linear cutting machine

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INCREASE OF STRAIN GAGE OUTPUT VOLTAGE SIGNALS ACCURACY USING VIRTUAL INSTRUMENT WITH HARMONIC EXCITATION

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Dependency of specific energy of rock cutting on specific drilling energy

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