The paper presents the results of preliminary research on the application of olivine moulding sands with hydrated sodium silicate containing 1.5 % wt. of binder to perform ecological casting cores in hot-box technology using a semi-automatic core shooter. The following parameters were used in the process of core shooting: initial shot pressure of 6 bar, shot time 3 s, the temperature of the corebox: 200, 250 and 300 °C and the core curing time: 30, 60, 90, 120 and 150 s. The matrix of the moulding mixture was olivine sand, and the binder of the sandmix was commercial, unmodified hydrated sodium silicate with molar module SiO2/Na2O of 2.5. In one shot of the automatic core-shooter were formed three longitudinal specimens (cores) with a dimensions 22.2×22.2×180 mm. The samples obtained in this way were subjected to the assessment of the influence of the shooting parameters, i.e. shooting time, temperature and curing time in core-box, using the following criteria: core box fill rate, mechanical strength to bending Rg U, apparent density, compaction degree and susceptibility to friability of sand grains after hardening. The results of trials on the use of olivine moulding sands with hydrated sodium silicate (olivine SSBS) in the process of core shooting made it possible to determine the conditions for further research on the improvement of inorganic hot-box process technology aimed at: reduction of the heating temperature and the curing time. It was found that correlation between the parameters of the shooting process and the bending strength of olivine moulding sands with sodium silicate is observed.

Phytophthora citricola Sawada was detected from 3 water pools situated in 2 container- grown nurseries. The highest number of spots on rhododendron leaves were observed in June whereas the lowest in October. The use of water for plant sprinkling caused browning, yellowing of shoots and root rot of Buxus sempervirens, and blight of shoot tips of Thuja occidentalis and Rhododendron sp. The disease symptoms were observed already in June and the disease developed till the first decade of October. Losses caused by the species varied from 9 to 56%.

This paper presents the modeling and simulation of a novel topology of quasi Z-Multilevel Inverter with stepped DC input. The proposed inverter incorporates a simple switching technique with reduced component count and is aimed at producing boosted multilevel output AC voltage. The inverter consists of two stages and the buck /boost operation is obtained by varying the shoot through period of the pulses obtained by maximum constant boost control with third harmonic injection. With all the advantages of the quasi Z-network, the proposed inverter eliminates the fly back diodes and capacitors present in a conventional Z-Multilevel Inverter. Further the stress on the devices is less which leads to reduction in component value and hence the cost. The novel stepped DC coupled Single Phase quasi Z-Multilevel Inverter is modeled and simulated in the MATLAB – SIMULINK environment and its performance is analyzed for varying input and switching conditions. The voltage and current waveforms across each stage of the inverter is analyzed and the results are presented for different levels of input.

An efficient system for plant regeneration of Senna occidentalis from hypocotyl-derived callus was developed. Callus was induced from leaf and hypocotyl explants on MS medium amended with 9.04 μM 2,4-D + 2.22 μM BAP and 10.74 μM NAA + 2.22 μM BAP. Medium browning due to leaching of compounds from callus was encountered and ameliorated through incorporation of 2.84 μM ascorbic acid. Leaf-derived callus showed no shoot induction ability, while hypocotyl-derived callus produced shoots in all cytokinin-amended treatments and also in combination with 2.68 μM NAA. For shoot formation, BAP-augmented treatments were better than medium with Kin added. Rhizogenesis was better on 1/2 MS basal medium with IBA than in the NAA and IAA treatments. Regenerated plants were acclimatized with 94% survival and showed similar morphology to field-grown plants.

To understand the molecular mechanism controlling in vitro plant morphogenesis, a culture system enabling induction of alternative morphogenic pathways (somatic embryogenesis, SE; shoot organogenesis, ORG) in a well defined population of somatic cells is needed. Arabidopsis is the most useful model plant for genomic studies, but a system in which SE or ORG can be induced alternatively in the same type of explant has not been proposed. Immature zygotic embryos (IZEs) of Arabidopsis provide the only explants with embryogenic potential, and have been recommended for studying mechanisms of SE induced in vitro. This study was aimed at defining culture conditions promoting induction of alternative morphogenic pathways: shoot ORG in IZE explants. The established protocol involves pretreatment of IZE explants with liquid auxin-rich callus induction (CIM) medium, followed by subculture on solid cytokinin-rich shoot induction medium (SIM). The method enables efficient shoot induction in Columbia (Col-0) and Wassilewskija (Ws), genotypes commonly used in molecular studies. During 3 weeks of culture up to 90% of Col-0 and 70% of Ws explants regenerated shoots via an indirect morphogenic pathway. We analyzed the qRT-PCR expression patterns of the LEC (LEC1, LEC2 and FUS3) genes, the key regulators of Arabidopsis embryogenesis, in the IZE explants induced to promote shoot ORG. The sharp decline of LEC expression on SIM medium confirmed that culture of Arabidopsis IZE explants enables experimental manipulation of the morphogenic response of somatic cells. A scheme illustrating various in vitro morphogenic responses of IZEs in relation to hormonal treatment is presented.

Virtual reality (VR) has become a realistic alternative to conventional learning methods in numerous fields including military training. Accurate and precise tracking of a user wearing a head-mounted display is necessary to achieve an immersive VR experience. The widely available SteamVR system, where licensed users can design and construct trackers optimized for a given application can be an alternative to very expensive professional motion tracking. This paper presents the complete design process of a SteamVR tracker dedicated to a shooting simulation in a VR environment.We describe the optimization and simulation of the tracker’s shape and configuration of the sensors. In the simulation phase the developed model had better parameters than its commercial counterparts. Next, the optimized prototype was constructed and configured. The dedicated and automated measuring arrangement provided experimental verification of the tracker’s performance. Tracking performance as well as the accuracy and precision of both position and orientation measurements were determined and compared with simulations, which proved that the simulation software can accurately predict selected properties of the proposed tracker.

Shoot tips excised from shoot culture of Salvia officinalis were encapsulated in 2% or 3% (w/v) sodium alginate and exposed to 50 mM calcium chloride for complexation. Immediately or after 6, 12 or 24 weeks of storage at 4°C, the synthetic seeds were cultured for 6 weeks on half-strength MS medium supplemented with indole-3-acetic acid (IAA) (0.1 mg/l) and solidified with 0.7% agar. The frequency of shoot and root emergence from encapsulated shoot tips was affected by the concentrations of sodium alginate and additives in the gel matrix (sucrose, gibberellic acid, MS nutrient medium) as well as duration of storage. The frequency of shoot and root induction of non-stored synthetic seeds was highest with shoot tips encapsulated with 2% sodium alginate containing 1.5% sucrose and 0.5 mg/l gibberellic acid (GA3). Shoot tips maintained their viability and ability to develop shoots even after 24 weeks of storage when they were encapsulated in 3% alginate with 1/3 MS medium, sucrose (1.5%) and GA3 (0.25 mg/l). Root formation tended to decrease with storage time. Overall, 90% of the plantlets derived from stored and non-stored synthetic seeds survived in the greenhouse and grew to phenotypically normal plants. This procedure can enable the use of synthetic seed technology for germplasm conservation of S. officinalis, a plant species of high medical and commercial value.

Centaurium erythraea plants obtained by indirect organogenesis are described in the paper. The plants were initiated from a single adventitious shoot regenerated from callus derived from the cotyledon of a 30-day-old seedling. The shoot was multiplied on MS medium supplemented with IAA (0.1 mg·L-1) and BAP (1.0 mg·L-1). The multiplication rate (28 shoots per culture within 4 weeks) was highest at the first subculture and decreased in further subcultures. The shoots were rooted on MS medium. The effect of IBA (0.1 mg·L-1) on the number of shoots forming roots differed depending on the composition of the basal medium (MS). The rooted shoots were transplanted to soil and grown in a greenhouse with 90% effectiveness. RAPD analysis was done with adventitious shoots of C. erythraea from in vitro culture. In shoots and whole plants regenerated from the callus tissue, secoiridoid content was determined by the HPLC method. We showed significant differences in morphology (leaf size, fresh and dry weight and height of plants) and changes in the DNA profiles as compared to earlier reports for shoot tip-derived shoots and plants of C. erythraea, but the two groups of plants biosynthesized the same qualitative pattern and similar levels of secoiridoids, up to 150 mg·g-1 dry weight; the increased biomass of plants regenerated from callus tissue makes them a better source of secondary metabolites.