Evolution of oxide and nitride inclusions during processing of stainless steel

Because of its superior properties, stainless steel has been widely used for many applications. Nonmetallic inclusions can influence the quality of stainless steel products. A set of samples was used to track the response of inclusion composition during processing of a heat of titanium-bearing 18% chromium steel, from deoxidation after decarburization, to the solidified slab. The oxide inclusions responded as expected to additions of deoxidizers and calcium treatment, changing from silica to alumina and spinels, and then to calcium aluminates. The samples confirmed that titanium nitride can nucleate on liquid calcium aluminate during steel solidification.

Liquid Inclusion Collision and Agglomeration in Calcium-Treated Aluminum-Killed Steel

This work addresses conflicting results in the literature regarding liquid inclusion agglomeration. To assess whether liquid calcium aluminates do agglomerate in liquid steel, laboratory experiments were performed: melting electrolytic iron, deoxidizing the melt with aluminum and subsequently calcium treating the deoxidation products (alumina and magnesia-alumina spinel inclusions). Under laboratory conditions, solid spinels and alumina inclusions were successfully modified, producing a new population of much smaller calcium aluminate inclusions. The new population of inclusions forms because the presence of calcium in the liquid steel destabilizes alumina and MgO-alumina inclusions, which then dissolve into the melt. The liquid inclusions exhibited a weak but statistically significant tendency to agglomerate. Laboratory results were assessed in the light of different collision mechanisms. Agglomeration mainly occurs by Stokes and laminar fluid flow collision when no external stirring is imposed. Monte Carlo simulations of collisions agree reasonably well with experimental results. For industrial conditions, where the liquid steel is agitated by argon bubbling and/or electromagnetic stirring, turbulent collisions dominate.

EFEK PUPUK CAIR KALSIUM TERHADAP PERTUMBUHAN DAN PRODUKSI TANAMAN KENTANG (SOLANUM TUBEROSUM L.)

The research effects of liquid calcium fertilizers on the growing and producing of potatoes (Solanum tuberosum L.) had properly done. The research was carried out on Lau Gumba Village, Berastagi Sub-district, Karo Regency, North Sumatra, December 2018- May 2019. Randomize Block Design with two factors i.e. Faktor I: Concentration of “BF” fertilizer, B0: control, B1: 2, 5 ml/96 ml of water, B2: 5 ml/ 96 ml of water, B3: 7, 5 ml/ 96 ml of water. Factor II: concentration of “BC” fertilizer, C0: control, C1: 1 ml/ 96 ml of water, C2: 2 ml/ 96 ml of water, C3: 3 ml/ 96 ml of water. The results of the study show that the concentration of the liquid calcium fertilizer had significantly impact (p < 0.05) to the growing and the production of tubers. The concentration of B3 (7,5 ml/96 ml of water) and C3 (3 ml/96 ml of water) had highest score 39.4 cm of plants’ height, The concentration of B3 (7, 5 ml/96 ml of water) and C3 (3 ml/96 ml of water) had significant impact to tubers’ weight.

THE INFLUENCE OF LIQUID CALCIUM SOURCE ON EGGSHELL QUALITY

It is estimated that the world’s population will enlarge by 25% by the middle of this century, resulting in the food production increase by at least 60%. Intensifying egg production is one of the most affordable solutions to provide animal protein. Among many other efforts to improve the quality of eggs, special attention is paid to attempts to provide a better endurance and strength of eggshell, due to the fact that the production of eggs with broken, cracked or soft shells incurs significant economic losses. One of the most important factors to achieve this goal is careful adjustment of calcium in the diet of laying hens, but the nutritional role of calcium is closely linked to that of phosphorus and the effect of vitamin D. The aim of the experiment was to determine whether two different nutritional supplements of calcium, applied in drinking water of laying hens for two weeks have any significant influence on the shell egg quality. Statistically very significant difference in egg production was observed in the treatment with the product containing calcium and phosphorus. On the other hand, the product consisting of calcium and vitamin D3 had no beneficial impact on the egg parameters. Based on the obtained results and literature data, it can be concluded that the amount and source of calcium in the diet of laying hens is a very complex and not fully solved issue. Therefore, especially keeping in mind the duration of the experiment, additional research is needed on this subject.

THE STUDY OF BIOCHEMICAL PARAMETERS OF BONE METABOLISM OF THE ORAL FLUID IN THE TREATMENT OF AGGRESSIVE PERIODONTITIS

Background. The analysis of the dynamics of biochemical parameters of bone metabolism of the oral fluid in the treatment of rapidly progressive periodontitis with the use of drugs Eplun, Metronidazole, Osteogenon and feel better. The most effective scheme of medical treatment was determined. We propose the use of EPLAN and Osteogenon in the complex treatment of aggressive periodontitis, and the use of Parodontax COMPREHENSIVE PROTECTION and Parodontax Classic mouthwash without alcohol for a rational hygiene of oral cavity. Objectives ― study the dynamics of biochemical parameters of bone metabolism of oral fluid in the treatment of aggressive forms of periodontitis. Methods. 100 patients aged from 26 to 35 years with a diagnosis of moderate CGP were examined. Depending on the prescribed treatment, all patients were divided into 4 groups by stratified randomization of 25 people. In the treatment of patients used medicines that are allowed to use: Eplun, Metronidazole, Osteogenon, homeopathic remedy. The study of biochemical parameters of oral liquid (calcium, phosphorus, alkaline phosphatase) in patients with present study included was carried out on the time frame: before treatment, after 3, 7 days, 1, 3, 6 and 12 months follow-up, patients in the control group – once. Results. The most pronounced changes in the biochemical parameters of the oral fluid, which led to the normalization of calcium, phosphorus and schf levels, were registered in the 4th group, in the complex therapy of which the drugs "EPLAN" and "Osteogenon" were used, and for rational oral hygiene, toothpaste Parodontax COMPLEX PROTECTION and rinse Rarodontax Classic without alcohol were used. Conclusions. The inclusion in the scheme of complex treatment of drugs "EPLAN" and "Osteogenon", and for rational oral hygiene, the use of toothpaste Parodontax COMPLEX PROTECTION and rinse Parodontax Classic alcohol-free was the most effective in the treatment of rapidly progressive periodontitis.

Thermodynamics on the Modification of Inclusions by Ca and Mg Treatment in GCr18Mo Bearing Steel

The effect of Mg and Ca treatment on the modification of inclusions in GCr18Mo bearing steel at 1873K was studied by thermodynamic calculations. The stability phase diagrams among Mg, Ca, Al, and O were investigated to understand the fundamentals about the formation of inclusions. The calculated results showed that: (1) Both the alumina and spinel can be modified to MgO by Mg treatment in the case of the dissolved [Mg] = 5.9ppm ~ 40ppm, corresponding the dissolved [Al] ≤ 0.056%, which can control the [O] ≤ 3ppm. (2) The MgO·Al2O3spinel can be modified to 12CaO·7Al2O3liquid inclusion by Ca treatment in the case of the optimal [Al] = 0.07% ~ 0.31% and the dissolved [Mg] ≤ 5.2ppm, the [O] can be controlled at about 3ppm. (3) The alumina can be modified to liquid calcium aluminate inclusions by Ca treatment in the case of the dissolved [Al] = 0.03% ~ 0.29% and the dissolved [Ca] = 13ppm ~ 80ppm, correspondingly the equilibrium [O] is about 3ppm. These results of thermodynamic calculation will provide a detailed thermodynamic reference for GCr18Mo bearing steel smelting.