STUDY OF MATERIALS AND WELDING USED IN THE CONSTRUCTION OF RACKS FOR STORAGE OF FUEL ELEMENTS AT NUCLEAR PLANTS

This paper showed the technological innovations and the necessary requirements for the welding of ASTM A240 TP316L Austenitic Stainless Steel in the construction of racks used in the storage of Fuel Elements inside nuclear power plants. It presents the development of welding processes using coated electrode, SMAW and as addition metal rods EAS 2-IG / ER 308L. This study is divided into two stages, the preparation of technical documentation and the development of methods and manufacturing processes used in the qualification of welding processes. A sequence was outlined based on real situations used by nuclear component manufacturing companies, meeting the physical and mechanical properties required by the nuclear classification standards and their regulations. The results showed that the welding processes were satisfactory, that the destructive and non-destructive tests showed that there was no discontinuity in the surface and defects in the volume of the welding and that, in the present study, safety in the project for the operation of a Nuclear Power Plant was demonstrated.

Credibility Assessment of Machine Learning in a Manufacturing Process Application

We present a framework for establishing credibility of a machine learning model used to predict a key process control variable setting to maximize product quality in a nuclear component manufacturing application. Our model coupled a purely data-based machine learning model with a physics-based adjustment that encoded subject matter expertise of the physical process. Establishing credibility of the resulting model provided the basis for eliminating a costly intermediate testing process that was previously used to determine the control variable setting.

Nuclear envelope reshaping around the vacuole determines the morphology of the ribosomal DNA

The ribosomal DNA array (rDNA) of Saccharomyces cerevisiae has served as a model to address chromosome organization. In cells arrested before anaphase (mid-M), the rDNA acquires a highly structured chromosomal organization referred to as the rDNA loop, whose length can double the cell diameter. Previous works established that complexes such as condensin and cohesin are essential to attain this structure. Here, we report that the rDNA loop adopts distinct morphologies that arise as spatial adaptations to changes in the nuclear morphology triggered during the mid-M arrests. Interestingly, the formation of the rDNA loop results in the appearance of a space under the loop (SUL) which is devoid of any nuclear component yet colocalizes with the vacuole. We finally show that the formation and maintenance of the rDNA loop and the SUL require TORC1 and membrane synthesis. We propose that the rDNA-associated nuclear envelope (NE) reshapes into a loop to accommodate the vacuole, with the nucleus becoming bilobed.

The DNA-to-cytoplasm ratio broadly activates zygotic gene expression in Xenopus

In multicellular animals, the first major event after fertilization is the switch from maternal to zygotic control of development. During this transition, zygotic gene transcription is broadly activated in an otherwise quiescent genome in a process known as zygotic genome activation (ZGA). In fast developing embryos, ZGA often overlaps with the slowing of initially synchronous cell divisions at the mid-blastula transition (MBT). Initial studies of the MBT led to the nuclear-to-cytoplasmic ratio model where MBT timing is regulated by the exponentially increasing amounts of some nuclear component N titrated against a fixed cytoplasmic component C. However, more recent experiments have been interpreted to suggest that ZGA is independent of the N/C ratio. To determine the role of the N/C ratio in ZGA, we generated Xenopus frog embryos with ~3-fold differences in genomic DNA (i.e., N) by using X. tropicalis sperm to fertilize X. laevis eggs with or without their maternal genome. Resulting embryos have otherwise identical X. tropicalis genome template amounts, embryo sizes, and X. laevis maternal environments. We used the X. tropicalis paternally derived mRNA to identify a high confidence set of exclusively zygotic transcripts. Both ZGA and the increase in cell cycle duration are delayed in embryos with ~3-fold less DNA per cell. Thus, DNA is an important component of the N/C ratio, which is indeed a critical regulator of zygotic genome activation in Xenopus embryos.

Nuclear genome-wide associations with mitochondrial heteroplasmy

The role of the nuclear genome in maintaining the stability of the mitochondrial genome (mtDNA) is incompletely known. mtDNA sequence variants can exist in a state of heteroplasmy, which denotes the coexistence of organellar genomes with different sequences. Heteroplasmic variants that impair mitochondrial capacity cause disease, and the state of heteroplasmy itself is deleterious. However, mitochondrial heteroplasmy may provide an intermediate state in the emergence of novel mitochondrial haplogroups. We used genome-wide genotyping data from 982,072 European ancestry individuals to evaluate variation in mitochondrial heteroplasmy and to identify the regions of the nuclear genome that affect it. Age, sex, and mitochondrial haplogroup were associated with the extent of heteroplasmy. GWAS identified 20 loci for heteroplasmy that exceeded genome-wide significance. This included a region overlapping mitochondrial transcription factor A (TFAM), which has multiple roles in mtDNA packaging, replication, and transcription. These results show that mitochondrial heteroplasmy has a heritable nuclear component.

The combined effect of nuclear and mitochondrial genomes on the risk of developing multiple sclerosis

Multiple sclerosis (MS) is a severe chronic CNS disease characterized by autoimmune inflammation, demyelination, and neurodegeneration. The interaction of mitochondrial and nuclear genomes is shown to be important in the formation of a predisposition to many diseases.Objective: to analyze the association of MS with the carriage of biallelic combinations, including as components the polymorphisms of three genes of mitochondrial DNA (mtDNA) and those of 16 nuclear genes, the products of which are involved in the functioning of the immune system and may participate in the development of autoimmune inflammation in MS; and, if these combinations are identified, to determine the nature of an interaction between their components. Patients and methods. The investigation enrolled 540 MS patients and 406 control group individuals; all were Russians. The mitochondrial genome was genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis. APSampler software was used for multilocus association analysis. Results and discussion. The investigators identified five biallelic combinations that were associated with MS (p=0.0036–0.022) and possessed protective properties (odds ratio (OR) 0.67–0.75). The mitochondrial component of the identified combinations was the polymorphisms m.4580 (rs28357975), m.13368 (rs3899498), and m.13708 (rs28359178) mtDNA; the nuclear component was CXCR5 (rs523604), TNFRSF1A (rs1800693), and CD86 (rs2255214) gene polymorphisms. The interaction between the components of the identified combinations was additive. Conclusion. The data obtained in the Russian population suggest that the combined contribution of the mitochondrial and nuclear genomes may affect the risk of developing MS.

Plasma Arc Welding for Code Compliance Nuclear Applications

Plasma Arc Welding (PAW) has been used for many critical applications due to its flexibility, reliability and high weld quality. In this paper, two code compliance plasma arc welding applications in the nuclear industry are discussed. The first application is an innovative welding process using PAW with specially designed dual hot wire feeding system, namely Dual Hot Wire Gas Metal Plasma Arc Welding (GMPAW). The GMPAW process offers unique advantages for high deposition and low dilution weld overlay application. The second application is a remote weld overlay repair from pipe inside diameter (ID) for a highly radiated nuclear component using PAW process with remote machining and NDE capability. In this paper, the benefits and advantages are provided for the aforementioned PAW applications. The versatility of plasma arc welding system configuration, as well as high quality and productivity can make plasma arc welding a good candidate for many critical code compliance applications.

Suggestive Phrases in the German Industrial Advertising Text (Based on the Material of Mining Equipment Advertising)

The present research featured German texts of mining equipment advertising, namely phrases with suggestive pragmasemantic potential. The research objective was to reveal the semantic characteristics of these language units. The article classifies and describes various pragmasemantic types of suggestive phrases using methods of componential, morphological, and syntactic analyses. The function of suggestion in mining equipment advertising proved to be of specific nature, as it has to oppose the conscious desire of a technical specialist to purchase effective and profitable equipment. The suggestion function in these texts belonged to words and phrases that created a positive image of the advertising object and suggestively described its usefulness to the consumer. A significant proportion of phrases contained the seme "safety", which could be explained by the following pragmatic presupposition: mining is highly dangerous; therefore, equipment should help to increase production safety. Such ergonomic characteristics of mining equipment as "controllability", "manufacturability", and "masterability" also depended on industrial safety. Most suggestive phrases appeared to have an adjective nuclear component, because German primarily uses adjectives to describe quality.