Features of assessing the condition and behavior of low-water bridges

The article describes features of operation and monitoring of low-water bridges, which are found on highways of regional, intermunicipal and local importance. Vibrations of the bridge span are considered in detail, taking into account its interaction with other structural elements and the environment. As a characteristic, the change of which takes into account the change in the state of the bridge structure, it is proposed to use the frequency of natural vibrations. To simulate the dynamic effects of transport and the dynamic behavior of individual elements and the entire structure as a whole, it is proposed to use viscoelastic elements of the Kelvin–Voigt type. When solving the problem, an approach has been implemented that makes it possible to take into account the anisotropic properties of the superstructure associated with various reinforcement along and across the roadway of the bridge, and to present the design scheme of the span not in the form of a beam supported at the edges with the help of hinges or viscoelastic dampers, but in the form of a plate, which can have different fxing conditions along the entire contour. The use of the proposed model and approach will make it possible to obtain the necessary data on the state of low-water bridges, for which there is often no possibility of visual inspection or instrumental inspection from the lower side of the bearing part of the superstructure. By the values of the frequency of natural vibrations, it is possible to estimate the water level above the low-water period and predict food situations, during which the roadway of the low-water bridge may be fooded.

There's more Wrangellia - Magnetic characterization of southern Alaska crust

In southern Alaska, Wrangellia-type magnetic crustal character extends from the Talkeetna Mountains southwest through the Alaska Range to the Bristol Bay region. Magnetic data analyses in the Talkeetna Mountains showed that there are mid-crustal differences in the magnetic properties of Wrangellia and the Peninsular terrane. After converting total field magnetic anomaly data to magnetic potential, we applied Fourier filtering techniques to remove magnetic responses from deep and shallow sources. The resulting mid-crustal magnetic characterization delineates the regional magnetic potential domains that correspond to the Wrangellia and Peninsular terranes throughout southern Alaska. These magnetic potential domains show that Wrangellia-type crust extends southwest to the Illiamna Lake region and that it overlaps the mapped Peninsular terrane. Upon reconsidering geologic ties between Wrangellia, Peninsular, and Alexander terranes we conclude that Peninsular terrane is part of what we here call Western Wrangellia. Western Wrangellia contains the Lower Jurassic Talkeetna volcanic arc and is similar to Wrangellia of the Vancouver Island area, Canada (Southern Wrangellia) which contains the Lower Jurassic Bonanza volcanic arc. Others have previously made this correlation and proposed that the Talkeetna arc-bearing part of southern Alaska was displaced from the Bonanza arc-bearing part of Canada. We generally agree and propose that about 1000 km of dextral displacement along ancestral Border Ranges fault segments and other faults of south-central Alaska separated Western Wrangellia from Southern Wrangellia. We think this displacement was mostly in the Late Jurassic and earliest Cretaceous, perhaps between about 160 and 130 Ma.

Occurrence of Tankhoy field coals in South Baikal bottom sediments

The purpose of the study is to describe the first finds of coal-bearing clays and coals in the bottom sediments of the southern basin of Lake Baikal and compare them with terrestrial coal-bearing deposits of the Tankhoy field. Comparative analysis of the lithological composition and colour of bottom sediments and terrestrial sections, as well as the concentration of organic carbon and conducted palynological analysis allowed their correlation. At the lake’s depth of 900 m the authors discovered a coal-bearing strata in situ (st 56), which later was stratigraphically correlated with the terrestrial coalbearing part of the Tankhoy suite. The fragments of coal found in bottom sediments basically along the entire Tankhoy field, especially bedrock coals on the underwater slope in South Baikal up to 1300 m deep prove the distribution of the coal-bearing part of the Tankhoy suite in the sublacustrine part of the lake throughout the entire slope (from 5 to 10 km offshore) and confirm the distribution area of the Tankhoy paleolake over a significant area of the contour of modern southern basin of Lake Baikal. The finds of coal-bearing strata on these and other various sub-bottom depths, i.e. under various pressure and temperature conditions, suggest that coals themselves and coal-bearing mudstones may be a generation facility of secondary microbial methane. This should be taken into account when searching for gas hydrocarbon and gas hydrate accumulations as well as assessing methane cycles in Lake Baikal.

Serial Section-Based Three-Dimensional Reconstruction of Anaxagorea (Annonaceae) Carpel Vasculature and Implications for the Morphological Relationship between the Carpel and the Ovule

Elucidating the origin of flowers has been a challenge in botany for a long time. One of the central questions surrounding the origin of flowers is how to interpret the carpel, especially the relationship between the phyllome part (carpel wall) and the ovule. Recently, consensus favors the carpel originating from the fusion of an ovule-bearing part and the phyllome part that subtends it. Considering the carpel is a complex organ, the accurate presentation of the anatomical structure of the carpel is necessary for resolving this question. Anaxagorea is the most basal genus in a primitive angiosperm family, Annonaceae. The conspicuous stipe at the base of each carpel makes it an ideal material for exploring the histological relationships among the receptacle, the carpel, and the ovule. In the present study, floral organogenesis and vasculature were delineated in Anaxagorea luzonensis and Anaxagorea javanica, and a three-dimensional model of the carpel vasculature was reconstructed based on serial sections. The results show that in Anaxagorea, the vasculature in the carpel branches in the form of shoots. The radiosymmetrical vasculature pattern is repeatedly presented in the receptacle, the carpel, and the funiculus of the ovule. This provides anatomical evidence of the composite origin of the carpel.

Improving the efficiency of metal-bonded diamond abrasive end tools by improving manufacturing technology

Introduction. Difficult-to-machine materials with enhanced physical and mechanical properties are increasingly being used in various industries. Such materials are used in mechanical engineering for the manufacture of parts and assemblies of machines and mechanisms, in the production and processing of food products where increased operational requirements are required. In modern production, along with traditional methods of intensifying technological operations, combined and hybrid processing technologies are used. For the finishing of products, abrasive grinding with a diamond tool is used. One of the problems hindering the wide practical application of this method in industry is the fact that it has a high prime cost caused by the cost of materials used in the manufacture and the laboriousness of the tool shaping process. This leads to the need to develop a new technology for manufacturing diamond tools. The purpose of the work is to increase the efficiency of the end diamond abrasive tool with a metal bond by using carbon steels as a body material, increasing the strength of the connection between the body and the diamond-bearing part, as well as choosing an effective tool manufacturing technology. Research methodology. To gain this task, a technology for manufacturing end diamond abrasive tools is developed and tested. Allowing using the technology of capacitor welding to connect the diamond-bearing part with the shank and use medium-carbon hardened high-quality steels with a hardness of 45-60 HRC as the shank material. The strength of the connection of the body with the working diamond-bearing part of the grinding head samples is determined by tensile testing on a 1958U10 tensile machine with maximum load 100 kN. The quality of the joint is assessed visually by the presence of discontinuities in the joint, as well as by examining the microstructure and measuring the microhardness of the weld and heat-affected zones. The microhardness of the welded joint is measured using an HMV-G21ST semi-automatic microhardness tester (Shimadzu, Japan) at a load of 50 g. Results and discussion. Thus, the results of comparative studies allow us to assert that the strength of the connection between the shank and the working diamond-bearing part according to the proposed technology surpasses similar characteristics of the strength of the connection between the shank and the diamond-bearing layer of grinding heads obtained by the method selected by the prototype. Conclusions. The proposed technology for the manufacture of diamond heads increases the strength of the connection between the body and the diamond-bearing working part, reduces the cost of manufacturing the grinding heads due to the use of hardened medium-carbon steels as the material of the tool body instead of high-speed steel grades, the technology is simplified and the possibility of automating the manufacture of tools appears.

Occurrence of Leaf Spot of Avena sativa Caused by Canariomyces microsporus in China

Oats (Avena sativa) are an important fodder crop in the vast ranges of northern and northwestern China, given the growing demand from livestock. (Yang et al. 2010). In July 2020, diseased leaf samples of cultivar Dingyan-2 were collected from fields near Gonghui Town, Zhangbei County, Zhangjiakou City (41.35° N, 114.55° E). These leaves showed oval to irregular yellowish-brown spots (0.5 to 6 mm in diameter) surrounded by a yellowish halo progressing to form narrowly striped spots fusing into lesions in severe cases. In a disease survey of six fields (about 1.5 ha in total), 35% of the plants were infected with a disease severity ranging from 0 to 20%. To isolate the pathogen, 12 symptomatic leaves (two leaves for each plant) were arbitrarily sampled from different locations across the fields and small pieces (5 mm2) of diseased leaves were excised from the border between diseased and healthy tissue. Excised tissue pieces were surface sterilized by immersion in 75 % ethanol for 30 s, then 1% NaClO solution for 1 min, rinsed in sterilized distilled water three times, and transferred to potato dextrose agar (PDA). Colonies on PDA were 41–46 mm diam in 10 d at 25 °C with surface texture floccose, obverse pale mouse grey to black due to ascomata and aerial mycelium, and reverse pale olivaceous. Asci were ellipsoidal to ovoid, 12–18 × 11–15 μm (av.= 15 ×12 μm; n=30) in spore-bearing part, containing eight irregularly arranged ascospores. Ascospores were 1-celled, dark brown when mature, smooth, ellipsoidal, with attenuated ends, 7.5–8.4 × 4.3–5.5 μm (av.= 8.1 × 5.0 μm; n=50), with an apical or slightly subapical germ pore. These morphological characteristics were consistent with previous descriptions of Canariomyces microsporus (syn. Thielavia microspora, Wang et al. 2019). For molecular identification, genomic DNA (isolate MNK-Y1) was extracted and the internal transcribed spacer (ITS) region and β-tubulin (tub2) were amplified and sequenced by using the primers ITS1 and ITS4 (White et al. 1990) and Btub2Fd and Btub4Rd (Woudenberg et al. 2009). Sequences were deposited in GenBank under accessions MW080329 (ITS) and MW557539 (tub2). Blast search revealed that the ITS and tub2 sequences matched 99.4%, 100% (471 bp out of 474 bp; 648 bp out of 648 bp) with the sequences of the ex-type isolate CBS 276.74 of C. microsporus accession number MH860852.1 and MK926899. Koch’s postulates were proven to confirm the pathogenicity of isolate MNK-Y1. Eight-week-old healthy oat seedlings of cv. Dingyan 2 were grown in the greenhouse, at 15-20 ℃ under 30-40% of relative humidity. Ten oat plants were spray inoculated with a spore suspension (5×105spores/ml; isolate MNK-Y1). Another ten oat plants were sprayed with sterile water as controls. All plants were covered with a transparent glass cover and a black polyethylene bag to maintain relative humidity and dark for two days. After 15 days, all the inoculated plants had developed yellowish-brown spots similar to those observed in the field whereas the control plants sprayed with sterile water remained healthy. The pathogen was reisolated from inoculated plants and identified as C. microsporus based on morphological characteristics and the molecular methods described above. This species has previously been isolated from saline and desert soils as well as from leaves of Thymus (Wang et al. 2019). To our knowledge, this is the first report of leaf spot of oat caused by C. microsporus in China.

The Formation of Micro-Diamonds in Decompression-Cracks During the Uplift of the Kimberlite Controlled by the C:O:H Ratio in NAMS

<p>We show new evidence that natural micro-diamonds can be formed in decompression-cracks by C:O:H bearing volatiles in a bimineralic eclogite. The investigated rock sample is a heterogeneous kyanite- bearing and bimineralic eclogite from the Roberts Victor mine, South Africa. Kyanite reacts out in the kyanite bearing part of the sample, but metastable relics are still present within the bimineralic part of the rock. The presence of these metastable kyanite relicts, suggest very low fH2O during the phase transition from the kyanite- bearing into the bimineralic eclogite. High-spatial-resolution synchrotron based FT-IR and RAMAN spectroscopy have been used to detect C:O:H-bearing volatiles around micro diamonds in planar defect structures in garnet in the bimineralic parts of the sample and N concentration has been analyzed within the micro-diamonds. In micro-diamond-bearing planar defect structures, a correlation between C:O:H-bearing volatiles can be identified whereas in micro-diamond -ree planar defect structures no correlation of the different C:O:H containing volatiles was detected. We suggest that the micro-diamond forming reaction was triggered by water released by the breakdown of water-bearing kyanite. We propose that the C:O:H bearing volatiles acted as a catalyst, changing in composition with changing P-T conditions in the rock during metamorphism. This catalytic process leads to permanent modification of C:O:H ratios and under favourable thermodynamic, stoichiometric and kinetic conditions micro-diamonds can be formed. Nitrogen concentrations in the analyzed micro-diamonds suggest that the formation of the micro-diamonds took place shortly before the uplift of the eclogite from the Earth mantle to the surface. The conclusions from our study proves that C:O:H-bearing volatiles, and their distribution pattern around the investigated micro-cracks, are indicative of the formation mechanisms of micro-diamonds controlled by C:O:H bearing fluids rather than by the solid-solid transformation from graphite into diamond.</p>

Analysis of Microstructure and Properties of High Strength Steel for Vehicle Axle

The vehicle axle is the main bearing part of the vehicle transmission, which needs to carry large power and torque. The axle is processed with high-strength steel. In order to verify the material properties of the axle and confirm whether it meets the design requirements, the chemical composition, mechanical properties, microstructure and metal inclusions of the axle are analyzed. The results show that the chemical composition of the material used in the axle meets the standard requirements, the parts with high hardness and tensile strength are tempered martensite, and the metal inclusions are mainly alumina inclusions, silicate inclusions and tin inclusions. Through the analysis of the performance of the axle, it is concluded that the axle material can meet the design requirements.

SHAPE OPTIMIZATION OF A TWO WHEELER SUSPENSION WITH DIFFERENT CROSS SECTIONS

The two-wheeler chassis consists of the frame, suspension, wheels and brakes. The chassis is what truly sets the overall style of the two-wheeler. Automotive chassis is the main carriage systems of a vehicle. The frame serves as a skeleton upon which parts like gearbox and engine are mounted. It can be made of steel, aluminum or an alloy. It keeps the wheels in line to maintain the handling of the two-wheeler.The frame of a motor vehicle supports all the drive assemblies, i.e. the engine, gearbox and axles (front and rear). In addition the suspension and steering systems and the shock absorbers are attached to it. The appropriate body is fixed to the chassis. It is essential that the frame should not buckle on uneven road surfaces and that any distortions which may occur should not be transmitted to the body. The frame must therefore be torsion−resistant. The frame of a motor vehicle is the load bearing part of the chassis which supports all forces (wheel forces) and weights. It should be as rigid as possible.The main aim of the project is to model a frame of a two wheeler using 3D modeling software Pro/Engineer. Two models of suspension are designed for pipe type and rectangular cross sections.Considering the frame as a beam, calculations are done to determine the displacement and stress by applying loads.To validate the strength of two models, Structural analysis is done by applying the wheel forces. In this analysis ultimate stress limit for the model is determined. Analysis is done for frame using two materials steel and aluminum to verify the best material for frame. Modal analysis is also done to determine natural frequencies of suspension frame. Analysis is done in ANSYS software.Comparison is done mathematically and by FEA analysis. And also we can validate the better cross section and material for suspension frame.

Dismantling of hipped roof and restoration of cribbed structure of monastic buildings, churches and temples

The paper is devoted to the problem of adaptation and restoration of monastic structures, churches and temples without complete dismantling of the elements of the main load-bearing structures, using technologies and methods of work that allow delicately and effectively restoring the most important elements of buildings. The progress of work on the restoration of the hipped roof, using the lifting method - lifting the load-bearing part of the cribbed roof structure, is accurately and consistently described in the paper, as well as flexibility and efficiency in choosing a new solution for lifting, taking into account the features of the object identified during the work. The work on raising the roof was carried out during the course of adapting the building to modern use, based on the needs of the Kirillo-Belozersky museum-reserve.