non-metallic inclusions Dotaz Zobrazit nápovědu
Improving the competitiveness of steel companies is linked to sustainable, quality-compliant steel production. Therefore, new steel production technologies contributing to increased cleanliness of steel are continuously being developed and optimized. One way to achieve a high steel quality is to use electro slag remelting (ESR) technology. In this paper, the principle of ESR technology and the importance of fused slags for optimizing the process are outlined. The aim of this work was to analyze the main thermophysical properties of steel and fused slags used in the ESR process. Determination of the properties of steel and slags was performed using the FactSage calculation software, which involved the calculation of the liquid and solid temperature of steel and slags, the calculation and construction of quaternary diagrams, and the calculation of viscosity. The resulting quaternary diagrams revealed the substantial influence of chemical composition on melting temperatures of slags. In order to validate the acquired results, a CrNiMoV-type steel was subjected to investigation of its metallographic cleanliness and evaluation of its mechanical properties; the ESR process was shown to significantly improve the cleanliness of the steel and improve the mechanical properties of the steel compared to its cleanliness and quality when produced via vacuum degassing (VD) technology. During the ESR process, the average size of non-metallic inclusions was reduced from 20 μm to 10 μm, and the maximum size of non-metallic inclusions was reduced from 50 μm to 28 μm. The mechanical properties of the steel produced using ESR technology were impacted as follows: the ductility increased by 10%, contraction increased by 18%, notched toughness at 20 °C increased by 46%, and at -40 °C (respectively -50 °C) it increased by 30%.
- Klíčová slova
- FactSage, electro slag remelting, metallographic cleanliness, non-metallic inclusions, slag, steel,
- Publikační typ
- časopisecké články MeSH
Ab initio calculations have been carried out to characterize the structure and energetics of a silver(I) complex with the cytosine-adenine DNA base pair and an aqua ligand in the coordination sphere of Ag. In addition, we have also studied analogous complexes with Cu(I) and Au(I), and structures in which adenine has been replaced by purine in order to investigate the structural role of the adenine amino group. The calculations revealed that all metal-modified structures are dominated by the metal-base interactions, while the water-metal ion interaction and many-body interligand repulsion are less important contributions. Nevertheless, the structural role of the water molecule in the complex is quite apparent and in agreement with an earlier crystallographic study. The metal-modified base pairs exhibit large conformational flexibility toward out-of-plane motions (propeller twist and buckle), comparable or, in some cases, even larger than that observed in the base pairs without metal ions. All structures have been optimized within the Hartree-Fock approximation, while interaction energies were evaluated with the inclusion of electron correlation.
- MeSH
- adenin chemie MeSH
- chybné párování bází * MeSH
- cytosin chemie MeSH
- kovy chemie MeSH
- měď chemie MeSH
- molekulární struktura MeSH
- stříbro chemie MeSH
- zlato chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- Názvy látek
- adenin MeSH
- cytosin MeSH
- kovy MeSH
- měď MeSH
- stříbro MeSH
- zlato MeSH
Screening of novel feedstuffs, that too for data-deficient (nutritionally) animals, is somewhat ambiguous or problematic. Through systematic meta-analyses, the present study formulated most up-to-date crayfish nutritional standards, against which a recyclable waste (biofloc biomass, BM) from intensive aquaculture systems was assessed as a novel protein source. Growth trajectory dependencies and thermal growth coefficient qualifying for good growth in crayfish (TGC 0.5-0.64 units) were benchmarked. Using these standards and a 7-week growth trial, BM's suitability as a novel protein source for red swamp crayfish Procambarus clarkii was evaluated through its graded inclusions in a commercial feed. Results suggest that BM can elevate growth at 33-66% inclusion in existing feed formulations. Beyond 66% inclusion, BM can deteriorate growth in crayfish due to high ash content (exceeding physiological limit > 14%), arginine deficiency (~ 14-20% lower than an optimum requirement), and insufficient non-protein energy: protein ratio (3.7 cal mg-1). Arginine is perhaps the most critical amino acid in dietary protein for crayfish, and deficient in BM. Although no critical bioaccumulation levels of heavy metals were breached by feeding 100% BM to crayfish, a mineral and heavy metal (Hg) stress seemed plausible. Crayfish raised solely on biofloc may not realize full growth potential.
- MeSH
- cichlidy MeSH
- fyziologický stres MeSH
- fyziologie výživy zvířat MeSH
- hepatopankreas chemie MeSH
- krmivo pro zvířata * MeSH
- odpadní produkty MeSH
- proteiny chemie farmakologie MeSH
- recyklace * MeSH
- severní raci chemie růst a vývoj fyziologie MeSH
- sladká voda MeSH
- těžké kovy analýza MeSH
- vodní hospodářství metody MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- odpadní produkty MeSH
- proteiny MeSH
- těžké kovy MeSH
Neutral (G.GC, A.AT, G.AT, T.AT, and C(imino).GC) and protonated (CH+.GC and AH+.GC) hydrogen-bonded trimers of nucleic acid bases were characterized by ab initio methods with the inclusion of electron correlation. In addition, the influence of metal cations on the third-strand binding in Purine-Purine-Pyrimidine (Pu.PuPy) reverse-Hoogsteen triplets has been studied. The ab initio calculations were compared with those from recently introduced force fields (AMBER4.1, CHARMM23, and CFF95). The three-body term in neutral trimers is mostly negligible, and the use of empirical potentials is justified. The only exception is the neutral G.GC Hoogsteen trimer with a three-body term of -4 kcal/mol. Protonated trimers are stabilized by molecular ion-molecular dipole attraction and the interaction within the complex is nonadditive, with the three-body term on the order of -3 kcal/mol. There is a significant induction interaction between the third-strand protonated base and guanine. The calculations indicate an enhancement of the third-strand binding in the G.GC reverse-Hoogsteen trimer due to-metal cation coordination to the N7/O6 position of the third-strand guanine. Interactions between metal cations and complexes of DNA bases are in general highly non-additive; the three-body term is above-10 kcal/mol in a complex of a divalent cation (Ca2+) with the GG reverse-Hoogsteen pair. The pairwise additive empirical potentials qualitatively underestimate the binding energy between cation and base.
- MeSH
- adenin chemie MeSH
- cytosin chemie MeSH
- DNA chemie MeSH
- guanin chemie MeSH
- kalorimetrie MeSH
- kationty MeSH
- konformace nukleové kyseliny * MeSH
- kovy MeSH
- molekulární modely MeSH
- molekulární struktura MeSH
- počítačová simulace MeSH
- software MeSH
- thymin chemie MeSH
- vodíková vazba MeSH
- zastoupení bazí MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- Názvy látek
- adenin MeSH
- cytosin MeSH
- DNA MeSH
- guanin MeSH
- kationty MeSH
- kovy MeSH
- thymin MeSH
In response to the growing demand for lightweight yet robust materials in electric vehicle (EV) battery casings, this study introduces an advanced carbon fiber-reinforced composite (CFRC). This novel material is engineered to address critical aspects of EV battery casing requirements, including mechanical strength, electromagnetic interference (EMI) shielding, and thermal management. The research strategically combines carbon composite components with copper-plated polyester non-woven fabric (CFRC/Cu) and melamine foam board (CFRC/Me) into a sandwich-structure composite plus a series of composites with graphite particle-integrated matrix resin (CFRC+Gr). Dynamic mechanical analysis (DMA) revealed that the inclusion of copper-plated fabric significantly enhanced the stiffness, and the specific tensile strength of the new composites reached 346.8 MPa/(g/cm3), which was higher than that of other metal materials used for EV battery casings. The new developed composites had excellent EMI shielding properties, with the highest shielding effectives of 88.27 dB from 30 MHz to 3 GHz. Furthermore, after integrating the graphite particles, the peak temperature of all composites via Joule heating was increased. The CFRC+Gr/Me reached 68.3 °C under a 5 V DC power supply after 180 s. This research presents a comprehensive and innovative approach that adeptly balances mechanical, electromagnetic, and thermal requirements for EV battery casings.
PURPOSE OF THE STUDY Radial head fractures in paediatric patients account for 5-19% of all elbow injuries and approximately 1% of all fractures in children. Non-displaced fractures are treated with plaster cast fixation. If the fracture is displaced, we proceed to closed reduction, or to osteosynthesis in case of unstable fragments. If closed reduction fails, we opt for open reduction and osteosynthesis. The prospective randomised clinical study aims to compare the two methods of minimally invasive osteosynthesis using the pre-bent Kirschner wire or Prévot nail and to identify differences between them. MATERIAL AND METHODS The prospective randomised clinical study was conducted in 2015-2019. The final cohort included 32 patients who met the inclusion criteria. The patients in whom other osteosynthesis implants had been used or in whom open reduction had to be performed were excluded from the study. Also excluded were the patients with serious concomitant injuries of elbow. For patients included in the cohort, demographic data, precise evaluation of the displacement and location of the fracture as well as the duration of plaster cast fixation and osteosynthesis implants used were recorded. In the clinical part, the methods were compared based on the achievement of full range of motion in dependence on the degree of original displacement, use of osteosynthesis implant, and occurrence of early and delayed complications. Clinical and radiological outcomes were compared. In both types of minimally invasive osteosynthesis, Métaizeau surgical technique was used. RESULTS Based on the clinical trial criteria, 26 (81%) excellent, 4 (13%) good and 2 (6%) acceptable outcomes were achieved. In 3 cases the loss of rotation was up to 20°, in 1 case the loss of flexion was up to 10°. In one patient the loss of flexion was 15° and rotation up to 30°. In another patient the loss of rotation was up to 40°. The radiological assessment showed 14 (44%) excellent outcomes, 15 good (47%) and 3 (9%) acceptable outcomes. The statistical analysis of both the groups of the cohort using non-parametric tests revealed no statistically significant differences in individual demographic parameters. The comparisons of both types of osteosynthesis in dependence on the degree of displacement by non-parametric Fisher's exact test showed no statistically significant difference in the radiologic or clinical results. The only statistically significant difference was observed in the duration of metal implant placement. DISCUSSION Comparable studies report excellent or good clinical outcomes in 80-95% of cases (1,13,16). In our cohort, excellent or good clinical outcomes were achieved in 30 patients (94%). In two patients, in whom Prévot nail was used, the outcomes were acceptable. Nonetheless, this fact did not result in any statistical significance when comparing the two methods separately or in comparisons based on the degree of displacement. CONCLUSIONS The comparison of the two methods of minimally invasive osteosynthesis revealed no statistically significant difference, namely not even when both the methods were compared based on the degree of displacement. When Kirschner wire is used, the possibility to remove the metal implant in the outpatient setting is considered to be an advantage. The drawback consists in potential penetration of the sharp Kirschner wire in the radiocapitellar joint, which we did not encounter when the second technique of osteosynthesis was used. The advantage of Prévot nail includes a lower risk of pin-tract infection. Key words: minimally invasive osteosynthesis, radial head, fracture, child.
- MeSH
- dítě MeSH
- fraktury vřetenní kosti * diagnostické zobrazování etiologie chirurgie MeSH
- kostní dráty MeSH
- lidé MeSH
- prospektivní studie MeSH
- radius zranění MeSH
- vnitřní fixace fraktury * metody MeSH
- výsledek terapie MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
