373 research outputs found

    Razrada tehnologije oblikovanja stožastih proizvoda od lima

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    The work presents a general knowledge about spinning draw pieces of sheets, one of multi-operational processes of spinning a sheet metal conical product without machining. The objective of the work was to elaborate both the technology of forming conical products of sheet metal and execution of technological tests as well as to determine the technological parameters for the process of spinning a conical insert. As a result of the investigations, the products with improved mechanical properties, stricter execution tolerance and low roughness have been obtained. The series of 200 prototype conical inserts for the shipbuilding industry have been made.Rad predstavlja opće saznanja o rotacijskom izvlačenju izradaka od lima, procesu višestrukih operacija procesa rotacijskog izvlačenja stožastog proizvoda lima bez operacija skidanja čestica. Cilj rada bio je razraditi tehnologiju oblikovanja stožastih proizvoda od lima i izvođenje tehnoloških ispitivanja kako bi se utvrdili tehnološki parametri procesa rotacijskog izvlačenja stožastog izratka. Kao rezultat istraživanja dobiveni su proizvodi s poboljšanim mehaničkim svojstvima, striktnijeg izvršenja niskih tolerancija i niže hrapavosti. Napravljena je serija od 200 prototipa stožastih izratka za brodogradnju

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    The title mol­ecule, C(12)H(12)FN(3)O(2)S, shows a short intra­molecular S⋯O contact of 2.682 (18) Å. The dihedral angle between the thia­diazole ring and the benzene ring is 86.82 (11)°. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds generate an R (2) (1)(6) graph-set motif between adjacent mol­ecules. Pairs of futher C—H⋯O hydrogen bonds form inversion dimers with R (2) (2)(8) ring motifs. These combine to generate a three-dimensional network and stack the mol­ecules along the b axis

    Effect of sow age on the apparent total tract digestibility of nutrients in the diet

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    Abstract The objective of this research was to evaluate the effect of sow age on apparent total tract digestibility of nutrients and the concentration of metabolizable energy in the diet. The experiment was carried out on 20 gestating sows, divided into two groups: Group I -10 sows in first pregnancy (131 ± 4.5 kg) and Group II -10 sows in fourth pregnancy (225 ± 8.2 kg). Sows in the two groups were fed identical diets for sows during early pregnancy. The total collection of faeces began on day 30 of pregnancy and lasted eight days. Sows in the fourth pregnancy had greater digestibility coefficients of dry matter (4.1 percentage units), organic matter (3.4 percentage units), crude protein (5.5 percentage units) and crude fibre (6.2 percentage units) than sows in the first pregnancy. The total tract digestibility of ether extract, starch and sugars was not affected by pig age. The metabolizable energy, determined according to the content of digestible nutrients, in the sow diet in fourth pregnancy was 0.7 MJ/kg higher than in the diet of sows in their first pregnancy. Results of this research indicate that sow age should be considered when formulating diets during early pregnancy

    Management of epithelial precancerous conditions and lesions in the stomach (MAPS II): European Society of Gastrointestinal Endoscopy (ESGE), European Helicobacter and Microbiota Study Group (EHMSG), European Society of Pathology (ESP), and Sociedade Portuguesa de Endoscopia Digestiva (SPED) guideline update 2019

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    Patients with chronic atrophic gastritis or intestinal metaplasia (IM) are at risk for gastric adenocarcinoma. This underscores the importance of diagnosis and risk stratification for these patients. High definition endoscopy with chromoendoscopy (CE) is better than high definition white-light endoscopy alone for this purpose. Virtual CE can guide biopsies for staging atrophic and metaplastic changes and can target neoplastic lesions. Biopsies should be taken from at least two topographic sites (antrum and corpus) and labelled in two separate vials. For patients with mild to moderate atrophy restricted to the antrum there is no evidence to recommend surveillance. In patients with IM at a single location but with a family history of gastric cancer, incomplete IM, or persistent Helicobacter pylori gastritis, endoscopic surveillance with CE and guided biopsies may be considered in 3 years. Patients with advanced stages of atrophic gastritis should be followed up with a high quality endoscopy every 3 years. In patients with dysplasia, in the absence of an endoscopically defined lesion, immediate high quality endoscopic reassessment with CE is recommended. Patients with an endoscopically visible lesion harboring low or high grade dysplasia or carcinoma should undergo staging and treatment. H. pylori eradication heals nonatrophic chronic gastritis, may lead to regression of atrophic gastritis, and reduces the risk of gastric cancer in patients with these conditions, and it is recommended. H. pylori eradication is also recommended for patients with neoplasia after endoscopic therapy. In intermediate to high risk regions, identification and surveillance of patients with precancerous gastric conditions is cost-effective.info:eu-repo/semantics/publishedVersio

    Antiparallel Dynamic Covalent Chemistries

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    The ability to design reaction networks with high, but addressable complexity is a necessary prerequisite to make advanced functional chemical systems. Dynamic combinatorial chemistry has, proven to be a useful tool in achieving complexity, however with some limitations in controlling it. Herein we introduce the concept of antiparallel: chemistries, in which the same functional group can be channeled into one of two reversible chemistries depending on a controllable parameter. Such systems allow both for achieving complexity, by combinatorial chemistry,, and addressing it, by switching from one chemistry to another by controlling an external parameter. In our design the two antiparallel chemistries are thiol disulfide exchange and thio-Michael addition, sharing the thiol as the common building block. By means of oxidation and reduction the system can be reversibly switched from predominantly thio-Michael chemistry to predominantly disulfide chemistry, as well as to any intermediate state. Both chemistries operate in water, at room temperature, and at mildly basic pH, which makes them' a suitable platform for further development of systems chemistry
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