Технологическая подготовка производства изготовления детали "Ступица" на станках с ЧПУ

В данной выпускной квалификационной работе рассмотриваются вопросы технологической подготовки производства детали "Ступица".ТПП включает в себя анализ технологичности, выбор способа получения заготовки, расчет припусков на обработку детали, проектирование технологического процесса, выбор технологического оснащения, кроме того был произведен расчет технико-экономических показателей технологического процесса и социальная ответственность на производстве.In this final qualification work, the issues of technological preparation for the production of the “Hub” part are considered. The TPP includes an analysis of manufacturability, a choice of the method for producing the workpiece, calculation of allowances for processing the part, design of the technological process, the choice of technological equipment, in addition, the calculation of technical and economic indicators technological process and social responsibility in the workplace

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Publisher Copyright: © 2022, The Author(s).Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes.Peer reviewe

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes

Precision and accuracy of single-molecule FRET measurements - a multi-laboratory benchmark study

Single-molecule Förster resonance energy transfer (smFRET) is increasingly being used to determine distances, structures, and dynamics of biomolecules in vitro and in vivo. However, generalized protocols and FRET standards to ensure the reproducibility and accuracy of measurements of FRET efficiencies are currently lacking. Here we report the results of a comparative blind study in which 20 labs determined the FRET efficiencies (E) of several dye-labeled DNA duplexes. Using a unified, straightforward method, we obtained FRET efficiencies with s.d. between ±0.02 and ±0.05. We suggest experimental and computational procedures for converting FRET efficiencies into accurate distances, and discuss potential uncertainties in the experiment and the modeling. Our quantitative assessment of the reproducibility of intensity-based smFRET measurements and a unified correction procedure represents an important step toward the validation of distance networks, with the ultimate aim of achieving reliable structural models of biomolecular systems by smFRET-based hybrid methods

Mechanochemistry for sustainable synthesis of framework materials

The following work presents the successful application of mechanochemical methods in the synthesis of framework materials, namely zeolites and sodium carboxylate coordination polymers. Common benefits of employing mechanical forces to aid and cause chemical reactions are typically decreased reaction times, lower amounts or avoidance of solvents, and highly efficient reactions, leading to overall more sustainable processes. A mechanochemically aided hydrolysis protocol for the second step of the ADOR (Assembly-Disassembly-Organisation-Reassembly) process was devised using zeolites with UTL framework as parent material. In contrast to conventional disassembly, which relies on the reaction occurring in solution at elevated temperatures, the use of a rotary ball mill allows for significant reduction of employed liquids (water or hydrochloric acid) and completion can be achieved on much shorter time scales. This reaction setup minimises waste production and requires lower energy input. Obtained intermediate zeolite phases can be reassembled into known daughter zeolites with *PCS, OKO, and PCR frameworks. The developed protocol and its low volumetric requirements for the hydrolytic reagent are not only beneficial from a purely synthetic point of view but could be applied successfully in the enrichment of product zeolite phases with the NMR active isotope 17O. Such enrichment procedures are typically time and energy consuming as well as carrying a high financial burden due to the low natural abundance of this isotope, which necessitates enrichment procedures in the first place. Several of the more complex zeolite frameworks are only obtainable as germanosilicate variant, suffering from the comparatively high cost of germanium reagents compared to silicon or aluminium analogues. In an attempt to extend the scope of the solvent-free route for zeolite synthesis, mechanochemical treatment of starting materials prior to the crystallisation reaction was performed, targeting four different frameworks. Reproducing literature reports, zeolites with ITH structure could be obtained. Further, materials with UOV structure were targeted, but instead yielding structurally related BEC zeolites. Synthesis of UTL was so far unsuccessful, but experiments additionally using seed crystals of the desired phase showed some preliminary success. Finally, pure silica and germanosilicate materials with ISV framework were synthesised for the first time using a solvent-free approach. Sodium carboxylates, members of the class of framework materials called coordination polymers, are promising candidates for organic-based anodes of sodium ion batteries, but face difficulties in large scale production. A mechanochemical synthesis route for sodium carboxylates using several, chemically varied organic carboxylic acids and the environmentally benign sodium acetate as source for the alkali metal, has been developed to alleviate most of these concerns. Produced materials show electrochemical performance on par with compounds obtained through conventional solution-based synthesis, with improved reaction conditions, avoidance of solvent and thus reduced waste

Mechanochemical synthesis of sodium carboxylates as anode materials in sodium ion batteries (dataset)

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Mechanomechanically assisted hydrolysis in the ADOR process

Funding: UK EPSRC (grant: EP/N509759/1) for funding of this work. D.N.R. also thanks the RSC for a Researcher Mobility Grant (no. M19-7166). R.E.M. is funded by the ERC Advanced Grant (787073 ADOR) and acknowledges the Charles University Centre of Advanced Materials (CUCAM) (OP VVV Excellent Research Teams, project number CZ.02.1.01/0.0/0.0/15_003/0000417).The ADOR (Assembly-Disassembly-Organisation-Reassembly) process for zeolites has been shown to produce a number of previously unknown frameworks inaccessible through conventional synthesis methods. Here, we present successful mechanochemically assisted hydrolysis of germanosilicate zeolite UTL leading to ADOR products under mild conditions, low amounts of solvent and in short reaction times. The expansion of zeolite synthesis into the realm of mechanochemistry opens up feasible pathways regarding the production of these materials, especially for industrial purposes, as well as an exciting application for economical enrichment of materials with the low natural abundance NMR-active isotope of oxygen, 17O. The results from mechanochemically assisted hydrolysis differ from those seen in the traditional ADOR approach: differences that can be attributed to a change in solvent availibility.Publisher PDFPeer reviewe