Infant formula, past and future: opportunities for improvement

Infant formulas provide nutritional support to health infants that promotes growth and development equivalent to that in healthy infants fed human milk. Formula-fed infants are not as well protected against infections, and there remain infants whose health, growth, and development may not be supported optimally by either the formulas currently available or human milk. Some infants may be better supported by genetically engineered formulas that contain immunity-enhancing antibodies or antigens. Formulas that contain cytokines promoting epithelial cell growth and integrity may be protective against necrotizing enterocolitis. Formulas containing proteins with genetically excluded allergenic epitopes or formulas with tolerogenic peptides may be useful in treating allergic diseases of suppressing the development of autoimmune disorders later in life. Formulas with genetically engineered biologically active substances might increase the absorption of nutrients in infants with compromised absorption or digestion, enhance host immunity and mucosal integrity, and, potentially militate or protect against the risk of disease.     

Dissolution of Lime in Synthetic ‘FeO’‐SiO2 and CaO‐‘FeO’‐SiO2 Slags

Dissolution of different CaO samples into molten synthetic ‘FeO’‐SiO₂ and ‘FeO’‐SiO₂‐CaO slags was carried out in a closed tube furnace at 1873 K. The slag was kept stagnant. It was found that the dissolution rate was very fast when CaO rod was dipped into ‘FeO’‐SiO₂ slag. In the case of ‘FeO’‐SiO₂‐CaO slag, the dissolution of CaO rod in the stagnant slag was retarded after the initial period (2 minutes). Only less than 16 percent CaO reacted with the slag, irrespective of the type of lime. Three phase‐regions were identified in the reacted part of the lime rod by SEM‐EDS analysis. The formation of these regions was explained thermodynamically. A dense layer of 2CaO · SiO₂ was found to be responsible for the total stop of the dissolution. It could be concluded that constant removal of the 2CaO · SiO₂ layer would be of essence to obtain a high dissolution rate of lime. In this connection, it was found necessary to study the dissolution of lime in moving slag to reach a reliable conclusion regarding the relevance of the reactivity obtained by water ATSM test to the real reactivity of lime in high temperature slag.     

Evaluation of Desulphurization Flux in CaO‐Al2O3‐BaO‐CeO2‐MgO System

The flux of the CaO‐Al₂0₃‐BaO‐CeO₂‐MgO system as a desulphurization flux containing no fluorine for the secondary metallurgy process was evaluated in this study. The flux composition was designed using the eutectic compositions of the binary systems. The melting and desulphurization abilities of the fluxes were evaluated by measuring their liquidus temperatures and the distribution ratios of sulphur between the fluxes and the carbon‐saturated iron or stainless steel. The lowest liquidus temperature of 1325°C was obtained by adding 5.7 mass% MgO to the 80mass%A‐20mass%B flux. (A: 12CaO‐7Al₂O₃, B: BaCeO₃+12mass%Al₂O₃). The distribution ratios of sulphur and sulphide capacities of the fluxes in this study were higher than those of the commercial product of calcium aluminate flux. This means that the CaO‐Al₂O₃‐BaO‐CeO₂‐MgO fluxes developed in this study have higher desulphurization and melting abilities compared with the commercial product of calcium aluminate flux.     

Mechanical properties of new stainless steels based on the system Fe‐30Mn‐5A1‐XCr‐0.5C

New stainless steels based on the system Fe‐30Mn‐5AI‐XCr‐0.5C (Cr mass contents of ≤ 9 %) were developed and evaluated as a replacement of conventional AISI 304 steel. The alloys were produced by induction melting and thermomechanically processed to obtain a fine equiaxed microstructure. A typical thermomechanical processing for AISI 300 austenitic stainless steels was used and included forging at 1200°C, rolling at 850 °C and final recrystallization at 1050 °C. A final fully austenitic microstructure with grains of about 150 μm in size was obtained in all the steels. Tensile tests at temperatures ranging from ‐196 to 400 °C showed similar results for the various alloys tested. In accordance with the values for the elongation to fracture, this temperature range was subdivided into three regions. In the temperature range of ‐196 °C to room temperature, elongation to fracture increases with decreasing temperature. At temperatures ranging from 100 to 300 °C, elongation to fracture increases with testing temperature and serrations on the stress‐strain curve were observed. Finally, higher testing temperatures were accompanied by a decrease in ductility. Examination of the microstructures after deformation led to the conclusion that mechanical twinning was the dominant mechanism of deformation at the tested temperatures.     

Thermodynamic assessment of CaO‐SiO2‐Al2O3‐MgO‐Cr2O3‐MnO‐FetO slags for refining chromium‐containing steels

The slag system of CaO‐SiO₂‐Al₂O₃‐MgO‐Cr₂O₃‐MnO‐Fe_tO relevant to refining chromium‐containing steels such as bearing steel is thermodynamically assessed at 1873 K. The activity coefficient of Fe_tO shows an initially rapid increment followed by a gradual reduction according to Cr₂O₃ content at a constant basicity, and decreases with increasing slag basicity. γ_MnO is decreased abruptly by increasing Cr₂O₃ content and thereafter, maintains a nearly constant level. From the standpoint of inclusion control, the Cr₂O₃ presence in ladle refining slags is thermodynamically harmful in that it minimizes the inclusion level by inducing the increment of γ_FetO even though Cr₂O₃ exists in extremely small amounts. However, it is beneficial in that it diminishes AI reoxidation by decreasing γ_MnO. The presence of carbon in slag decreases γ_FetO and γ_MnO, which turns out to be favourable for the reduction of Al reoxidation. The thermodynamic equilibria of chromium and manganese are quantified in terms of Fe_tO and Cr₂O₃ content as well as slag basicity by using multiple regression analysis. L_Cr and L_Mn are increased by the presence of Cr₂O₃, indicating a low recovery efficiency of Cr and Mn in the treatment of ferroalloy addition. In determining L_S values, Cr₂O₃ is not so important as the basicity of slags.     

Thermodynamic Activity of Chromium Oxide in CaO‐SiO2‐MgO‐Al2O3‐CrOx Melts

Thermodynamic activities of chromium oxide contained in CaO‐SiO₂‐MgO‐Al₂O₃ melts were measured in the present work using gas‐slag equilibrium technique. The oxygen partial pressure was varied (10^‐3, 10^‐4, 10^‐5 Pa). Gas mixture of CO, CO₂ and Ar were used and investigated at 1803, 1873 and 1923 K. The activities of CrO showed a strong positive deviation from ideality and a decrease with increasing temperature and oxygen partial pressure. A mathematical expression relating the amount of chromium oxide in the slag phase with the activity of Cr in the metal phase based on the present experimental results is presented.     

In‐Situ Measurement of CO‐ and CO2‐Concentrations in BOF Off‐Gas

Improvement of the efficiency and productivity of steelmaking requires accurate and real‐time process information to precisely adjust the tapping conditions. The response time of BOF process control systems is commonly depending on the time needed for off‐gas sampling and analysis. A FTIR based measurement system was adapted and installed at an industrial steel converter of ArcelorMittal España S.A. in Aviles. An advanced data interpretation routine based on the quantum mechanical fundamentals of remote infrared (IR) spectroscopy was developed to enable precise determination of the {CO}‐ and {CO₂}‐concentrations, resp. their ratio, in the off‐gas. The results of the industrial measurement showed the ability of the FTIR based system for real‐time measurement of temperature, {CO}‐ and {CO₂}‐concentrations in the hot and dusty off‐gas. The influence of dust at the chosen defined optical path lengths in the IR wavelengths region can be neglected, but the collector lens clean has to be kept clean.     

Transformation Conditions ‐ Microstructures ‐ Mechanical Properties Relationship in 0.60%C Hypoeutectoid Steel

The relationship between transformation conditions, microstructures and mechanical properties were investigated on a 0.60%C hypoeutectoid steel, which has predominantly pearlitic microstructure. The steel had been austenized at 850‐1050 °C and then isothermally transformed at 570‐660 °C. Afterwards, the microstructures were analyzed by optical microscope, scanning electron microscope, and quantitative metallography. And the mechanical properties were determined. The results indicated that the interlamellar spacing, the pearlitic colony size and the proeutectoid ferrite content follow a linear relationship with the reciprocal of the undercooling, and the strength, the hardness and the toughness follow a Hall‐Petch type of relationship with the inverse of the square root of the interlamellar spacing. Besides, the stress condition should be taken into account during analyzing the effect of the interlamellar spacing on the mechanical properties. The results have been explained on the basis of transformation conditions ‐ microsturctures ‐ mechanical properties ralationship.     

Simulation of the γ–α‐transformation using the phase‐field method

Phase transformation is a powerful tool to change the properties of steels. Of the known transformations especially the γ–α‐transformation is utilised. It occurs in a temperature range relevant for heat treating and hot deformation processes. In this paper an approach is presented in which the γ–α‐transformation is simulated with Micress. This software applies the multicomponent multiphase‐field model, which is based on the reduction of total free enthalpy. Two different steels have been selected for the simulations, an ULC and an IF steel. Dilatometric tests serve as a basis for the simulations. These tests have shown that the transformation behaviours of the two steel grades are governed by two different kinetics. The transformation kinetics of the IF grade is influenced by the microalloying concept applied, resulting in a very slow start of the transformation. This has also been incorporated in the simulations by choosing two different grain boundary mobilities, one main parameter of the simulation. The simulation results of the ULC grade show the huge influence of nucleation undercooling as another one of the main parameters. Both simulation results are satisfying. They show that the phase‐field method offers a strong simulation tool in the area of phase transformation.     

Mechanical Behavior of Deformation‐Induced α′‐Martensite and Flow Curve Modeling of a Cast CrMnNi TRIP‐Steel

For the modeling of the mechanical behavior of a two phase alloy with the rule of mixture (RM), the flow stress of both phases is needed. In order to obtain these information for the α′‐martensite in high alloyed TRIP‐steels, compression tests at cryogenic temperatures were performed to create a fully deformation‐induced martensitic microstructure. This martensitic material condition was subsequently tested under compressive loading at ?60, 20, and 100°C and at strain rates of 10^?3, 10⁰, and 10³ s^?1 to determine the mechanical properties. The α′‐martensite possesses high strength and surprisingly good ductility up to 60% of compressive strain. Using the flow stress behavior of the α′‐martensite and that of the stable austenitic steel AISI 316L, the flow stress behavior of the high alloyed CrMnNi TRIP‐steel is modeled successfully using a special RM proposed by Narutani et al.     

Galvannealing of (High‐)Manganese‐Alloyed TRIP‐ and X‐IP®‐Steel

In this study the influence of Mn on galvannealed coatings of 1.7% Mn‐1.5% Al TRIP‐ and 23% Mn X‐IP®‐steels was investigated. It is shown that the external selective oxides like Mn, Al and Si of the TRIP steel which occur after annealing at 800 °C for 60 s at a dew point (DP) of ‐25 °C (5% H₂) hamper the Fe/Zn‐reaction during subsequent galvannealing. Preoxidation was beneficially utilized to increase the surface‐reactivity of the TRIP steel under the same dew point conditions. The influence of Mn on the steel alloy was investigated by using a 23% Mn containing X‐IP®‐steel which was bright annealed at 1100 °C for 60 s at DP ‐50 °C (5% H₂) to obtain a mainly oxide free surface prior to hot dip galvanizing (hdg) and subsequent galvannealing. As well known from the literature Mn alloyed to the liquid zinc melt stabilizes δ‐phase at lower temperatures by participating in the Fe‐Zn‐phase reactions, it was expected that the metallic Mn of the X‐IP®‐steel increases the Fe/Zn‐reactivity in the same manner. The approximation of the effective diffusion coefficient (D_eff(Fe)) during galvannealing was found to be higher than compared to a low alloyed steel reference. Contrary to the expectation no increased Fe/Zn‐reaction was found by microscopic investigations. Residual η‐ and ζ‐phase fractions prove a hampered Fe/Zn‐reaction. As explanation for the observed hampered Fe/Zn‐reaction the lower Fe‐content of the high‐Mn‐alloyed X‐IP®‐steel was suggested as the dominating factor for galvannealing.     

Sulphide Capacities of CaO‐SiO2‐Al2O3‐MgO Slags

In Japanese steelworks, hot metal is now being produced by a scrap melting process. With this process, removals of sulphur is very much handicapped because of very high sulphur levels (0.04‐ to 0.09‐ pct by weight) and relatively low tapping temperatures (1623 to 1723 K). In order to overcome such handicaps, the authors explored on the respective phase diagrams. These explorations revealed that {CaO‐SiO₂‐Al₂O₃‐MgO} slags with Al₂O₃ contents of 30‐ to 35‐pct by weight would be good candidates as reagents for sulphur removal from high sulphur hot metal at relatively low temperatures. For better understanding of the thermodynamic properties of the candidate slags, in this study, sulphide capacities were determined through gas/slag equilibrium technique. The experimental results suggest that there would be, at least, a “window” to remove sulphur from high sulphur hot metal as relatively low temperatures.     

Thermodynamic Behaviour of Chlorine in CaO‐SiO2‐MgO‐Al2O3(‐CaF2) Slags

The solubility of chlorine in CaO‐SiO₂‐Al₂O₃‐MgO(‐CaF₂) slag was measured at 1673 ‐1823 K. By estimating the chloride capacity of slags, thermodynamic behaviour of chlorine in the molten slag was investigated. Chloride capacity increased with increasing CaO / SiO₂ ratio (C/S). An increase in MgO content decreased chloride capacity at C/S≥1.0 because it lowered the activity of Ca²⁺ which seemed to have strong affinity with Cl^? in molten slag. Also, the chloride capacity decreased with increasing Al₂O₃ content. The affinity between the Ca²⁺ and Cl^? ions was confirmed by measuring the infrared spectra of slags. The dissolution reaction of chlorine into slag was exothermic and its molar enthalpy was evaluated from the experimental results at 1673 ‐ 1823 K. Based on the result obtained in the present study, the quantitative prediction of chlorine distribution during the blast furnace process was performed. It was estimated that almost all chlorine in the blast furnace would be absorbed into molten slag even if the PCI ratio was increased or low quality coal with chlorine content less than 1.0 mass% was injected.     

Home care past, present, and future: opportunities and challenges in a managed care environment

This article describes the history of Medicare-based home care and the changing requirements of the home care industry as the reimbursement models continue to evolve. Medicare-based home care was once seen as an ancillary service of the hospitals. Now, with the advent of managed care, home care provides new options and opportunities and is facing new challenges at both the local and the national levels. Current proposals in Washington, such as bundling, co-pays, and a Prospective Payment System, will have farreaching effects on the industry. This article discusses the various reimbursement models, including Medicaid, Medicare HMOs, managed care, and capitation, and identifies key areas and opportunities for home care in the future.