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The increase in the share of physical and technical processing methods in the arsenal of deburring technologies used in modern production is associated both with the use of difficult-to-machine materials, such as beryllium bronze and the 29 NK alloy, and with the need to solve technological problems for the production of small-sized products with hard-to-reach surfaces. The aim of the study is to improve the processes of blade processing of small-sized parts made of beryllium bronze and the 29 NK alloy to provide rational conditions for thermal pulse deburring. Surface samples were experimentally obtained after turning in different modes on a CITIZEN CINCOM K16E-VII automatic lathe equipped with an Applitec micromechanics tool. The surface quality and burr characteristics were examined using a JEOL JIB-Z4500 electron microscope and a ContourGT-K optical profilometer. The program Statistica 6 allowed processing of the results. The relationship between the parameters of the turning mode and the thickness of the root of the burrs formed on the machined surface, the limitation of which is one of the conditions for the application of the thermal pulse method, was established. The obtained empirical regression dependencies establish a rational range of cutting mode parameters, and the implementation of the formulated recommendations for setting blade modes ensures deburring by the thermal pulse method in compliance with the requirements of drawing under maximum processing performance.

There is much contradiction between different experimental studies on beryllium (Be) toxicity. The majority of studies focus on occupational pathologies, caused by the exposure to Be dust. However, Be pollution may affect wide population groups through other exposure routes. The discrepancies between experimental studies may be attributed to the lack of adequate Be toxicity model since conventional administration routes are hampered by high acidity and low solubility of Be compounds. This study was aimed to develop a novel way to implement Be toxicity avoiding side effects, related to high acidity or low solubility of Be salts. Intraperitoneal injection of Be–glycine composition (containing BeSO4, glycine, purified water, pH adjusted to 5.5 with NaOH) was tested in the dose range 238–7622 µmol Be kg−1 (body weight, b/w) in full-grown Wistar male rats. The model provided reliable uptake of Be from the peritoneum into general circulation for at least 48 h. LD50 was found to be 687 µmol Be kg−1 (b/w). The established LD50 value differed from previous data on gastrointestinal, intramuscular or intravenous administration of Be compounds. The liver was found to act as a primary elimination route for Be and related to the highest Be content in the animal. However, it had no signs of morphological damage, which was observed only in the testes (deterioration of germinal epithelium). At the same time, the lungs, stated as a primary target tissue for Be in the models of chronic beryllium disease, did not show strong Be accumulation nor morphological changes. Survived animals showed behavioral changes, including increased motor activity and aggressive reactions in some cases, and complete spasticity in other. The obtained data show the applicability of the established modeling protocol and testified for the independence of chronic beryllium disease on Be2+ ion toxicity per se.

Beryllium, possessing unique nuclear physical properties, is currently widely used as a material for reflector and neutron moderator blocks of research nuclear reactors. It can also be applied in fusion energy as a first-wall material and neutron multiplier. However, when beryllium is irradiated, its physical-mechanical properties deteriorate due to radiation-induced microstructural damage, the generation of tritium and helium, the activation of impurities under the radiation exposure, and the absorption of fission products, which determines the need for periodic replacement of the beryllium components in nuclear installations. Moreover, due to the relatively low abundance of beryllium, a relevant problem is its purification from radioactive isotopes for potential reuse. To date, chlorination has emerged as one of the most promising methods for purifying irradiated beryllium. This study addresses the optimization of the chemical process parameters and the isolation of the beryllium component from the resulting mixture of chlorination products, including the most active radionuclides: 3 H, 60 Co, 108m Ag, and 137 Cs. Laboratory-scale experiments confirmed the effectiveness of the irradiated beryllium chlorination technology for its purification. The reduction in the activity level of beryllium and its compounds was objectively monitored using gamma and beta spectrometry methods.

Reconstructing Cenozoic history of continental silicate weathering is crucial for understanding Earth’s carbon cycle and greenhouse history. The question of whether continental silicate weathering increased during the late Cenozoic, setting the stage for glacial cycles, has remained controversial for decades. Whereas numerous independent proxies of weathering in ocean sediments (e.g., Li, Sr, and Os isotopes) have been interpreted to indicate that the continental silicate weathering rate increased in the late Cenozoic, beryllium isotopes in seawater have stood out as an important exception. Beryllium isotopes have been interpreted to indicate stable continental weathering and/or denudation rates over the last 12 Myr. Here we present a Be cycle model whose results show that variations in the ⁹Be weathering flux are counterbalanced by near-coastal scavenging while the cosmogenic 10Be flux from the upper atmosphere stays constant. As a result, predicted seawater 10Be/⁹Be ratios remain nearly constant even when global denudation and Be weathering rates increase by three orders of magnitude. Moreover, 10Be/⁹Be records allow for up to an 11-fold increase in Be weathering and denudation rates over the late Cenozoic, consistent with estimates from other proxies. The large increase in continental weathering indicated by multiple proxies further suggests that the increased CO₂ consumption by continental weathering, driven by mountain-building events, was counter-balanced by other geological processes to prevent a runaway icehouse condition during the late Cenozoic. These processes could include enhanced carbonate dissolution via pyrite weathering, accelerated oxidation of fossil organic carbon, and/or reduced basalt weathering as the climate cooled.

—Along with technological aspects, an analysis of the interaction of components of molten salt mixtures is significant for the development of models of the structures of molten salts. From this point of view, it seems interesting to study the influence of the anionic composition of electrolytes on a possible structure of the melts. The construction of the composition–property diagrams at various temperatures of the processes is an efficient way of physicochemical analysis of the interaction of components of salt compositions. The use of molar values for properties is the most correct in this respect. The data on the concentration dependence of molar volumes of molten salt mixtures of alkaline metal and beryllium chlorides and fluorides are presented. The molar volumes are calculated from the data on the density of the corresponding melts, which have been obtained by the authors and other researchers and published previously. Mixture compacting (decreasing molar volume) in the concentration range close to 30 mol % beryllium halide is observed in the systems containing alkaline metal and beryllium chlorides and in analogous fluoride systems. A decrease in the molar volume increases on going from lithium halide to cesium halides. Such a change in the properties is characteristic of the beryllium-containing electrolytes and is caused by the charge and small radius of the beryllium ion, which favors the intensification of its interaction with anions. The properties of the anions also affect the ionic interaction: the compacting in the chloride systems is somewhat higher than that in the corresponding fluoride systems. The concentration range of the maximum compacting of the molten salt mixtures corresponds to the stoichiometry of complex M 2 BeHal 4 , where M is alkaline metal, and Hal is Cl or F. The further increase in the beryllium halide concentration in the mixture results in melt structure loosening, which is reflected as a flat maximum on the molar volume isotherms. The concentration coordinate of the maximum is close to that corresponding to the stoichiometry of compound MBe 2 Hal 5 . Such congruently melted compounds are also present in the MCl–BeCl 2 and MF–BeF 2 systems. No similar points are observed in the MCl–BeF 2 systems on both the fusibility curves and molar volume isotherms.

Forcing the East Asian summer monsoonWhat factors have controlled the intensity of the East Asian summer monsoon over the recent geological past? To answer this key question requires a robust proxy for rainfall amounts. Beck et al. measured the beryllium isotopic content of loess from China, from which they reconstructed a 550,000-year-long record of rainfall. Rainfall correlated with orbital precession and global variations in ice volume. This finding suggests that the monsoon is governed by low-latitude interhemispheric gradients in solar radiation levels, rather than by high-northern-latitude solar radiation levels as previously suggested.Science, this issue p. 877Cosmogenic 10Be flux from the atmosphere is a proxy for rainfall. Using this proxy, we derived a 550,000-year-long record of East Asian summer monsoon (EASM) rainfall from Chinese loess. This record is forced at orbital precession frequencies, with higher rainfall observed during Northern Hemisphere summer insolation maxima, although this response is damped during cold interstadials. The 10Be monsoon rainfall proxy is also highly correlated with global ice-volume variations, which differs from Chinese cave δ18O, which is only weakly correlated. We argue that both EASM intensity and Chinese cave δ18O are not governed by high-northern-latitude insolation, as suggested by others, but rather by low-latitude interhemispheric insolation gradients, which may also strongly influence global ice volume via monsoon dynamics.

Micro-liquid floated gyroscopes are widely used in nuclear submarines, intercontinental missiles, and strategic bombers. The machining accuracy of micro-ball sockets determined the motion accuracy of the rotor. However, it was not easily fabricated by micro-cutting because of the excellent physical and chemical properties of beryllium copper alloy. Here, we presented a linear compensation of tool electrode and a proportional variable thickness method for milling micro-ball sockets in C17200 beryllium copper alloy by micro-electrical discharge machining. The machining parameters were systematically investigated and optimized to achieve high-precision micro-ball sockets when the k value was 0.98 and the initial layer thickness was 0.024 mm. Our method provided a new way to fabricate micro-ball sockets in C17200 with high efficiency for micro-liquid floated gyroscopes.

Differential cross sections for nuclear fragment yields at an angle of 3.5° in the fragmentation of carbon ions with an energy of 0.95 and 2.0 GeV/nucleon on a beryllium target have been measured. The momentum spectra of the fragments were used for testing predictions of few models of ion-ion interactions.

Charge-exchange cross sections in Be[sup.4+] + H(1s) collisions are calculated using the three-body classical trajectory Monte Carlo method (CTMC) and the quasi-classical trajectory Monte Carlo method of Kirschbaum and Wilets (QCTMC) for impact energies between 10 keV/amu and 300 keV/amu. We present charge-exchange cross sections in the projectile n = 2 and nl = 2s, 2p states. Our results are compared with the previous quantum-mechanical approaches. We found that the QCTMC model is a powerful classical model to describe the state-selective charge-exchange cross sections at lower impact energies and the QCTMC results are in good agreement with previous observations.