Friction is often accompanied by local fracture at the boundary of contacting bodies. The space between contacting bodies usually contains moving particles of a different nature, and a change in the ...effective friction conditions can be associated with a change in the structure of the contact area. This paper presents a new series of experiments where balls simulated the particles of the intermediate layer interacting with an elastic layer of different thickness. The effects of regularization when the balls approached each other were investigated considering different initial configurations (line and spatial structure). The balls simulated the particles of the intermediate layer interacting with the elastic layer of different thickness. The opposite effects of convergence and separation of the balls were observed in different experiments. A model of mutual effect during the contact of two balls with a two-layered elastic half-space was developed. An analysis of tangential forces due to the mutual effect was performed for different layer thicknesses, its relative compliance, and different distances between the balls. It was found that the input parameters defined the sign of the tangential force, which led to the convergence or the separation of the balls. The results can be used to create structures controlling the motion in the intermediate layer.
The TORIO-229 experiment aims for a direct model-independent determination of the transition energy of
229
m
Th produced in
233
U alpha decay. This knowledge will be of interest for the development ...of a scientific clock exploiting the thorium isomeric state, which would be able to significantly surpass the precision of the presently best clocks. As a detector for the isomeric transition, it is planned to use an array of fast transition-edge sensors (TESs) which demonstrated to be feasible in our previous work where the Ir/Au TES prototype demonstrated
4.6
±
1.7
µs rise time,
5.8
±
2.1
µs fall time and
0.789
±
0.023
eV energy resolution and signal-to-noise ratio of
∼
10 with one-photon (2.824 eV) signal, satisfying the experimental requirements. Such a microcalorimeter will allow to register the transition in every possible channel in the energy range from 3 to 50 eV and with a lifetime of > 5 µs. To have a full characterization of a single TES for the final detector array design, its thermal conductance has to be measured. In this contribution, we report on a test measurement of thermal coupling of a TORIO-229 prototype-like iridium-gold TES.
We present new data on the Bjorken sum Γ‾1p−n(Q2) at 4-momentum transfer 0.021≤Q2≤0.496 GeV2. The data were obtained in two experiments performed at Jefferson Lab: EG4 on polarized protons and ...deuterons, and E97110 on polarized 3He from which neutron data were extracted. The data cover the domain where chiral effective field theory (χEFT), the leading effective theory of the Strong Force at large distances, is expected to be applicable. We find that our data and the predictions from χEFT are only in marginal agreement. This is somewhat surprising as the contribution from the Δ(1232) resonance is suppressed in this observable, which should make it more reliably predicted by χEFT than quantities in which the Δ contribution is important. The data are also compared to a number of phenomenological models with various degrees of agreement.
Purpose. To provide a comprehensive characterization of the first selective breeding generation of the Antoninsko-Zozulenetsky intrabreed type of Ukrainian carp breeds at the 3rd and 4th year of life ...based on piscicultural and biological parameters. Methodology. The material for the study were age-2+ and age-3+ Antoninsko-Zozulenetsky carps. The main piscicultutral and biological parameters were studied during spring valuation and autumn harvest according to generally accepted methods in fish farming. The external evaluation of the experimental groups was carried out according to the following parameters: body weight and length, body depth, body girth. Measurements were made with a centimeter tape with an accuracy of 1 mm. Individual weighing of fish was carried out on electronic commercial scales with an accuracy of 1 g. Based on the results of the measurements, following exterior parameters were analyzed and determined: girth index, body length to depth ratio, head index. Findings. The study showed that both age-2 and age-3 framed carp had a lower weight loss rate of 11.95 and 10.11%% compared to 12.89 and 12.73%% in the scaly form. The yield from wintering was within 88.6–89.8% of age-2 fish and 88.9–89.3% of age-3 fish. The average body weight gain age-2+ framed carp during the season was 1.3 kg, the scaly carp - 1.1 kg. On the fourth year of life, this parameter in scaly carp was 1.6 kg, framed carp - 1.5 kg. Survival rate during the growing season was higher than standard values and was on average 96.8% in age-2+ fish and 95.9% in age-3+ fish. According to external parameters, age-2+ framed carp had higher values of the body length to depth ratio by 0.3, compared to their peers with a scaly cover. The advantage of this experimental group was also in terms of condition factor: 2.56 versus 2.26. On the other hand, among age-3+, scaly individuals had an advantage according to the body length to depth ratio. Age-3+ framed carp prevailed in terms of the condition factor. Originality. A comparative analysis of piscicultural and biological parameters of the replacement and brood stock of the first selection generation of the Antoninsko-Zozulenetsky intrabreed type of carp was carried out in the conditions of Ukraine for the first time. Practical value. The use of brood fish of a new inbred type with defined features of the genotype will allow obtaining new promising lines for industrial cultivation at different levels of intensification of aquaculture and in different climatic zones, as well as hybrids between geographically isolated populations. Key words: carp, selective breeding, intrabreed type, generation, exterior, weight, condition factor.
Purpose. To create stocks of age-1 and 1+ carp produced with the use of defrosted and native sperm and provide the comprehensive characteristics of their quantitative and qualitative parameters. ...Methodology. The material for the study were age-1 and 1+ Nyvky scaly and non-scaly carp. Main quantitative and qualitative parameters were studied during spring assessment and autumn harvest using conventional aquaculture methods. Stocking density of age-0+ fish for wintering was 10 thousand kg/ha, age-1 fish – 1 thousand fish/ha. The exterior assessment of multiple age groups was carried out using following parameters: body weight and length, body depth, body circumference. Measurements were done using a measuring tape with a precision of 1 mm. Fish were weighed individually on electronic balances with a precision of 1 g. Following main exterior indices were determined and analyzed: circumference index, body length to depth ratio, head index. Findings. The study showed that age-1 fish produced from defrosted sperm had 0.25 and 4.5% higher survivability during wintering with the prevalence of non-scaly carp, however they were characterized by higher weight loss: 1.13% for scaly carp and 1.65% for non-scaly carp. Age-1+ fish produced from defrosted sperm prevailed over their age-0+ by weight by 2.69% for scaly carp and by 7.34% for non-scaly carp. However, fish of the experimental group were characterized by lower survivability by 1.0% and 3.25% compared to the control group. Fish productivity parameters during the study period varied from 810.7 to 1056.0 kg/ha. Originality. For the first time in Ukraine, a comparative analysis of quantitative and qualitative parameters of age-1 and 1+ carp produced with the use of defrosted and native sperm was performed. Practical value. Use of the method of cryopreservation of sperm obtained from brood fish with desired peculiarities of genotype allows improving creation of highly productive stocks using methods of individual selection, getting highly productive crosses as well as hybrids between geographically isolated populations. Key words: carp, defrosted sperm, age-1 fish, age-1+ fish.
Purpose.In the last decade, due to increasing requirements for providing the Ukrainian population with the most valuable dietary food products, the importance of aquaculture has increased ...significantly. At the same time, an increase in the amounts of cultured fish as well as other agricultural products is possible only through the introduction of highly productive objects of cultivation using economically feasible technologies. Therefore, in today’s conditions, domestic breeders are conducting active selective breeding and scientific work with carp resulting in the approval of the Antoninsko-Zozulenets intrabreed type of the Ukrainian framed and scaly breeds. Findings.The authors of the work reviewed and analyzed the specialized scientific literature on the historical aspects of the development of carp breeding in Ukraine, and the role of the Antoninsko-Zozulenets carp in the selective breeding work. In particular, the genetic composition of scaly and framed carp, the breeding schemes of new intrabreed types, and the proportion of Antoninsko-Zozulenets carp blood in them were analyzed. Practical value.The conducted review of literary sources can be useful for the preparation of lecture material during the educational process of training specialists in the specialty 207 “Aquatic bioresources and aquaculture”, in particular, specialists in ichthyology and zoology. Key words: reproduction, selective breeding, genetics, carp culture, breed, intrabreed type.
The centre of resistance and centre of rotation of a tooth are key concepts in orthodontics. Determining the coordinates of these points is essential for planning orthodontic tooth movement. The ...paper proposes a procedure for experimental determination of the two centres, verifies a previously developed mathematical theory through computer simulations and evaluates the effect of nonlinearity of the periodontal ligament on the parameters related to the centres. The paper relies on the mathematical theory of a rigid body embedded in an elastic medium, physical experiment, finite element method and a simple nonlinear theory of the tooth. The concept of the centre of resistance requires a revision if nonlinearity is taken into account.
The development of methods for cleaning marine vessels and stationary underwater structures such as oil platforms from crustacean foulers requires the study of their mechanical properties, data on ...the strength of shells – fouling houses and their attachment to the substrate. The methods and results of mechanical testing for crack resistance of fragments of shell houses of Chirona evermanni from the Sea of Okhotsk and houses of Balanus eburneus from the Barents Sea that are attached to a stone substrate are presented. The conditions of brittle fracture during the development of a crack in the shell and the separation of the shell from the substrate are determined.
The Reversed Field Pinch (RFP) configuration looks to be an attractive option for fusion-fission hybrid reactors: the toroidal magnetic systems would be made of copper coils instead of more expensive ...superconductive magnets; fusion conditions could be reached by ohmic heating only, therefore additional heating systems would not be required; the fission blanket could be located in the most external part of the torus thus facilitating maintenance operations. The paper aims at assessing the potentialities, such as fuel fertilization and/or nuclear waste transmutation and electricity production of a hybrid reactor with a RFP fusion core (R = 6 m, a = 1) whose conceptual design and plasma performances are based on RFX-mod, the largest RFP experiment currently in operation. Fusion conditions can be reached by heating a D-T plasma up to 9.6 keV by ohmic heating, generated by a 20 MA plasma current induced and sustained by flux swing only. The neutron flux (2.1 × 1013 fast neutron/cm2/s) is used to breed tritium in both the inner and outer blanket sections and induce fission reactions in dedicated areas in the external blanket section where Pu + MA (60%)-Zr (40%) rods are located. Both neutronic and safety analyses corroborate the viability of a FFH reactor with a RFP core.
Crossbred underyearlings produced by crossing few-scaled type of Ukrainian framed carp strain and Nyvka scaled type of Ukrainian scaled carp strain were evaluated. Planned organization of ...reproduction of the best strains, their types, the aim of which is to obtain hybrids, makes it possible to rear fish seeds with better performance than pure-bred carp. Presence of high-yielding strains in the breeding fund of Ukraine allows to widely apply the method of industrial cross-breeding. However, it is important to know which combination of strains or species shows heterosis with a certain economic parameters. Searches for the best heterosexual combinations is an important step towards improving the productivity. Over the past 20 years, Ukrainian carp farming has been enriched by new breeding achievements -- Nyvka scaled, Liubyn scaled and framed, as well as the few-scaled intrabreed types, the effectiveness of which has been insufficiently studied for industrial crossing. Fish farming features of crossbred underyearlings of Nyvka scaled and Lebedyn few-scaled strains are presented. Use of new crosses and pure-bred carp will contribute to an increase in the productivity of fishery water bodies.
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