c-ideals in complemented posets

In their recent paper on posets with a pseudocomplementation denoted by * the first and the third author introduced the concept of a *-ideal. This concept is in fact an extension of a similar concept introduced in distributive pseudocomplemented lattices and semilattices by several authors, see References. Now we apply this concept of a c-ideal (dually, c-filter) to complemented posets where the complementation need neither be antitone nor an involution, but still satisfies some weak conditions. We show when an ideal or filter in such a poset is a c-ideal or c-filter, respectively, and we prove basic properties of them. Finally, we prove so-called Separation Theorems for c-ideals. The text is illustrated by several examples

Sheffer operations in complemented posets

We show that in every downward directed poset with an antitone involu-tion the so-called Sheffer operation can be introduced satisfying certain identities.However, also conversely, if we have given a Sheffer operation|on a setP, thenPcan be converted into a poset with an antitone involution′, where both′and theorder relation≤are derived by|. Using this, we can characterize orthoposets, i.e.bounded posets with complementation which is an antitone involution by means ofidentities satisfied by this Sheffer operation. Also conversely, if|is a Sheffer oper-ation on a given setPsatisfying these identities, thenPcan be organized into anorthoposet

Resistance Spot Welding of dissimilar Steels

This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA). Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials

Alternative approaches to vibration measurement due to the blasting operation: A pilot study

As the infrastructure grows, space on the surface in the urban area is diminishing, and the view of the builders is increasingly moving underground. Implementation of underground structures, however, presents a number of problems during construction. One of the primary side effects of tunnel excavation is vibration. These vibrations need to be monitored for potential damage to structures on the surface, and this monitoring is an integral part of any such structure. This paper brings an original pilot comparative study of standard seismic instrumentation with experimentally developed fiber-optic interferometric and acoustic systems for the purpose of monitoring vibration caused by the blasting operation. The results presented show that systems operating on physical principles (other than those previously used) have the potential to be an alternative that will replace the existing costly seismic equipment. The paper presents waveform images and frequency spectra from experimental measurements of the dynamic response of the rock environment, due to blasting operation performed shallowly during the tunnel excavation of a sewer collector. In the time and frequency domain, there is, by comparison, significant agreement both in the character of the waveform images (recording length, blasting operation timing) and in the spectra (bandwidth, dominant maxima).Web of Science1919art. no. 408

Phyllotactic model linking nano and macro world

Recently, the arrangement of diffraction primitives according to a phyllotactic model was presented. This arrangement was used to benchmarking purposes of the e-beam writer nano patterning. The phyllotactic arrangement has several interesting properties. One of them is related with the coherence between the nano-or microscopic domain of individual optical primitives and the properties of visually perceived images crated by these structures in the macro domain. This paper presents theoretical analysis of the phyllotactic arrangement in the referred context. Different approaches enabling the creation of diffractive optically variable images are proposed. The practical part of the presented work deals with the nano patterning of such structures using two different types of the e-beam pattern generators. One of them is a system with a variable shaped beam of electrons, while the other one is a system with a Gaussian-shaped beam. E-beam writing strategies and the use of inherent spiral patterns for exposure ordering and partitioning are also discussed.TACR [TE 01020233]; MEYS CR [LO1212

Surface Integrity after Turning a Duplex Stainless Steel with Respect to Tool Geometry

This study deals with surface integrity expressed in terms of stress state as well as microstructure alterations after turning a duplex stainless steel. Residual stresses and the presence of strain-induced martensite are studied as functions of the rake angle. Residual stresses of surface and sub-surface layers were determined by the use of the X-ray diffraction and hole-drilling techniques. X-ray diffraction enables us to distinguish between residual stresses in each phase separately, which is not possible when the hole-drilling method is applied. Furthermore, alterations in the near surface region are also analysed by the use of the magnetic Barkhausen noise and metallographic observation

Artificial inoculation of maize seeds with Sporisorium reilianum f. sp. zeae

The objective of this research was to identify an inoculation method of Sporisorium reilianum f. sp. zeae, causal agent of the head smut of maize, which allows a high and consistent percentage of infection, for reliable selection of germplasm with genetic resistance to this pathogen. Seeds of the hybrid AZ 41801 were inoculated with telio-spores impregnated using as adherents: 1% (w/v) sodium carboxymethylcellulose (NaCMC) 1%, ADH®, 2% (w/v) sodium alginate 2%, 50% (w/v) brown sugar 50% (w/v), 2% (w/v) agar – agar, 10% (w/v) grenetin and a treatment 1: 200 (v/v) of inoculum: soil 1: 200 (v/v). Treated seeds were planted in a greenhouse in 40 x 40 cm polyethylene pots with sterile soil. In 2015, grenetin as adherent, induced 96.3% of diseased plants in greenhouse. Morphological and molecular characterization of the pathogen was carried out before the inoculation and after the finalevaluation. This method of inoculation was evaluated in 2016 in fieldconditions in Mixquiahuala, Hgo. A total of 160 lines C2-S3 from a bmaize population improvement program were inoculated with teliospores of S. reilianum f. sp. zeae using 10% grenetin as adherent. The incidence of the disease in both experiments planted in 2015 and 2016 was evalua-ted 45 days after flowering,with direct observation of symptoms and signs in male and female infloescences. One line showed 54.5% of infection. The hybrid AZ 41801 reached 70.7% of diseased plants. It is suggested to use 10% grenetin as adherent in the inoculation of maize seeds with teliospores of S. reilianum f. sp. zeae for the selection of disease resistant germplasm

New methods to seismic monitoring: Laboratory comparative study of Michelson fiber-optic interferometer and pneumatic measurement systems

New possibilities of vibration monitoring can be found in completely different physical approaches, where all measuring technology is currently based on sensors in the electrical domain. This paper presents two different promising alternative approaches to vibration measurement, specifically in the field of fiber-optics and pneumatic sensors. The proposed solution uses a Michelson fiber-optic interferometer designed without polarization fading and with operationally passive demodulation technique using three mutually phase-shifted optical outputs. Experimentally developed sensor systems for the registration of anthropogenic seismic phenomena were complemented by standard instrumentation for measuring seismicity used as a standard. The measurement was performed under simplified conditions using a calibrated stroke as a source of dynamic loading. In addition to alternative systems, the paper also presents the results of recalculation of the measured values in a time domain and basic relationships for the conversion to basic units derived from the SI (International System of Units) system and used internationally in the field of seismic engineering. The results presented demonstrate that even systems operating on a different physical principle have great potential to replace the existing seismic devices. The correlation coefficients for both sensory devices were high (above 0.9) and the average deviations from the measured values of the amplitude of the oscillation velocity did not exceed the value of 0.02, neither with the fiber-optic or pneumatic sensor.Web of Science85art. no. 14