The cheesemaking potential of milk concentrated up to four-fold by ultrafiltration and heated in the range 90–97 °C

1990 ◽  
Vol 57 (4) ◽  
pp. 549-557 ◽  
Author(s):  
Margaret L. Green

SummaryProperties of interest to cheesemaking were investigated with milks concentrated by ultrafiltration and heated at 90 °C or 95–97 °C for 15 s. The effects of light homogenization before concentration and of addition of CaCl2 after heating were assessed. No changes in casein–fat or casein–whey protein interactions were detected by electron microscopy. The heat denaturation of whey protein increased linearly as the milk became more concentrated. Coagulability by rennet after heat treatment increased with concentration to close to the unheated value in 3·5 to 4-fold concentrates. The decrease in curd firming rate by heat treatment was slightly affected by concentration and addition of CaCl2 restored some of the difference. Heat treatment reduced the rate of whey loss and slightly improved the curd structure but did not affect fat losses. Light homogenization slightly reduced heat denaturation of whey protein and whey loss.

Author(s):  
Hidenori Terasaki ◽  
Tomohiro Tanaka ◽  
Masamitsu Abe ◽  
Mitsuyoshi Nakatani

We investigated the effects of post-weld heat treatment conditions on the microstructure of the multi-pass submerged arc weld metal of 9Cr-1Mo-V steel used in pressure vessels. The microstructural properties were analyzed under three conditions (as-weld, Larson-Miller parameter (LMP) = 21.38 × 103, and LMP = 21.99 × 103). The precipitation behavior was observed using scanning electron microscopy, and the difference in precipitation behavior in the “as-welded” and “reheated” regions of the prepared multi-pass weld metal was clarified at the different LMP values. The precipitate was analyzed using scanning transmission electron microscopy. An oxide and two types of precipitates were identified, and a dislocation network pinned by MX-type carbides was visualized under the low-LMP condition. The effects of LMP on the effective grain size and dislocation amount were also evaluated using electron back-scattering diffraction. All microstructural change along the LMP had a positive effect on the toughness of weld metal.


2003 ◽  
Vol 18 (3) ◽  
pp. 693-701 ◽  
Author(s):  
M. Endo ◽  
Y. J. Kim ◽  
K. Ishii ◽  
T. Inoue ◽  
T. Nomura ◽  
...  

The heat-treatment retention time effect of carbonized polyvinylidenechloride (PVDC) was investigated. Homogeneous PVDC with a crystallite size of 267 Å was used as a precursor material for an electric double-layer capacitor electrode. The P-120m material, which was heat treated for 120 min at 700 °C, shows a larger specific capacitance than any other material in this study. It shows the largest values reported up to now, reaching values as high as 100.2 F/g for a two-electrode system, which is equivalent to 400.8 F/g in a conventional three-compartment electrode system. It is difficult to distinguish the difference in the pore-size distribution by way of gas adsorption as the retention time is varied. However, the difference can be clarified using a novel method based on the analysis of transmission electron microscopy images. As the retention time for heat treatment increases, the pore size grows through the coalescence of small pores. Furthermore, a new concept for the electric double-layer capacitance is suggested on the basis of analysis of the transmission electron microscopy observations.


1984 ◽  
Vol 51 (1) ◽  
pp. 29-36 ◽  
Author(s):  
L. M. J. Heppell ◽  
A. J. Cant ◽  
P. J. Kilshaw

1. Residual antigenic protein in heat-denatured cow's milk whey and in two commercial infant milk formulas was determined using enzyme-linked immunosorbent assays specific for β-lactoglobulin, α-lactalbumin, bovine serum albumin, bovine IgG1 and α-casein. This immunochemical assessment of antigenicity was related to the capacity of the preparations to sensitize immunologically when fed to guinea-pigs for 2 weeks. Antibody production was measured and the susceptibility of the animals to systemic anaphylaxis was assessed by injecting them intravenously with heated or unheated milk proteins.2. Whey protein that had been heated at 100° or 115° for 30 min was extensively denatured and, in contrast to pasteurized whey, failed to sensitize guinea-pigs for anaphylaxis. Antibody production was undetected or very low. The proteins in SMA powder and SMA Gold Cap liquid concentrate were less denatured and animals given these formulas prepared according to the maker's instructions produced relatively high levels of antibodies to β-lactoglobulin and α-casein and a majority developed anaphylaxis when injected intravenously with these products.3. As well as failing to sensitize, whey that had received severe heat treatment did not, in most cases, elicit anaphylaxis when injected into animals that had been sensitized with unheated milk.4. Discrimination between antibodies of the IgG1 and IgG2 subclasses specific for β-lactoglobulin showed that IgG1, the principal anaphylactic antibody in guinea-pigs, was preferentially depressed in animals drinking heat-denatured milk preparations.5. The results suggest that heat denaturation of whey protein may be a logical and simple strategy for producing a hypoallergenic baby milk. Nevertheless, the value of experiments in guinea-pigs for predicting results in man is uncertain and the proposal awaits assessment in clinical trials.


Author(s):  
R. M. Anderson

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.


Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.


Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 608
Author(s):  
Jinkun Lu ◽  
Haichun Jiang ◽  
Lingying Ye ◽  
Daxiang Sun ◽  
Yong Zhang ◽  
...  

The effect of aging time on the crushing performance of Al-0.5Mg-0.4Si alloy used for safety components of automobile was investigated by tensile test and crush test. Moreover, the microstructure of the alloy was investigated by transmission electron microscopy (TEM). The results show that the localized deformation ductility index, ΔAabs, which is defined as the difference between total elongation and uniform elongation, of Al-0.5Mg-0.4Si alloy is 6.5%, 7.0% and 8.5%, respectively, after being aged at 210 °C for 1, 3 and 6 h, and this tendency is the same as that of the crushing performance. The spacing of grain boundary precipitates (GBPs) from TEM results are found to be 94.9, 193.6 and 408.2 nm after being aged at 210 °C for 1, 3 and 6 h, respectively, and this tendency is same to that of ΔAabs. A mechanism about the relation between the spacing of GBPs and the ductility index ΔAabs has been proposed based on localized deformation around GBPs. With the increase of GBPs spacing, the ΔAabs increases, and the crushing performance is improved.


2015 ◽  
Vol 48 (3) ◽  
pp. 836-843 ◽  
Author(s):  
Oindrila Mondal ◽  
Manisha Pal ◽  
Ripandeep Singh ◽  
Debasis Sen ◽  
Subhasish Mazumder ◽  
...  

The effect of dopant size (ionic radius) on the crystal growth, structure and optical properties of nanocrystalline calcium titanate, CaTiO3(CTO), have been studied using small-angle neutron scattering. X-ray diffraction, along with high-resolution transmission electron microscopy, confirms the growth of pure nanocrystalline CTO. Rietveld analysis reveals that the difference of ionic radii between dopant and host ions induces strain within the lattice, which significantly affects the lattice parameters. The induced strain, due to the difference of ionic radii, causes the shrinkage of the optical band gap, which is manifested by the redshift of the absorbance band. Mesoscopic structural analysis using scattering techniques demonstrates that the ionic radius of the dopant influences the agglomeration behaviour and particle size. A high-resolution transmission electron microscopy study reconfirms the formation of pure highly crystalline CTO nanoparticles.


2014 ◽  
Vol 783-786 ◽  
pp. 692-697 ◽  
Author(s):  
Andrew Clark ◽  
Randy J. Bowers ◽  
Derek O. Northwood

The effects of heat treatment on distortion, residual stress, and retained austenite were compared for case-carburized 4320 steel, in both the austempered and quench-and-tempered condition. Navy C-ring samples were used to quantify both size and shape distortions, as well as residual stress. The austempering heat treatment produced less distortion and a higher surface residual stress. Both hoop and axial stresses were measured; the difference between them was less than seven percent in all cases. Depth profiles were obtained for residual stress and retained austenite from representative C-ring samples for the austempered and quench-and-tempered heat treatment conditions. Austempering maintained a compressive residual stress to greater depths than quench-and-tempering. Quench-and-tempering also resulted in lower retained austenite amounts immediately beneath the surface. However, for both heat treatments, the retained austenite content was approximately one percent at depths greater than 0.5 mm.


2016 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Zhiyuan Liang ◽  
Wanhua Sha ◽  
Qinxin Zhao ◽  
Chongbin Wang ◽  
Jianyong Wang ◽  
...  

AbstractThe effect of aging heat treatment on the microstructure and mechanical properties of 10Cr20Ni25Mo1.5NbN austenitic steel was investigated in this article. The microstructure was characterized by scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy. Results show that the microstructure of 10Cr20Ni25Mo1.5NbN austenitic is composed of austenite. This steel was strengthened by precipitates of secondary phases that were mainly M23C6 carbides and NbCrN nitrides. As aging treatment time increased, the tensile strength first rose (0–3,000 h) and then fell (3,000–5,000 h) due to the decrease of high density of dislocations. The impact absorbed energy decreased sharply, causing the sulfides to precipitate at the grain boundary. Therefore, the content of sulfur should be strictly controlled in the steelmaking process.


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