High Solution Treatment Research Articles

Bacillus subtilis Promotes Cucumber Growth and Quality under Higher Nutrient Solution by Altering the Rhizospheric Microbial Community

Bacillus subtilis was applied in peat-based soilless cultivation systems containing a mixed substrate (peat:vermiculite:perlite = 2:1:1, v/v/v) and irrigated by one-strength or four-strength Hoagland's nutrient solution to explore whether it can alleviate inhibition by higher-nutrient solutions (four-strength) and bring benefits to improvements of quality. The results showed that higher-nutrient solutions improved the flavor quality of cucumber fruit; especially, the contents of (E,Z)-2,6-nonadienal and (E)-2-Nonenal were effectively increased, which are the special flavor substances of cucumber. B. subtilis K424 effectively improved growth performance, photosynthetic capacity, vitamin C content, soluble sugars, soluble protein, and total pectin in cucumber under higher nutrition solution conditions. Compared with the higher solution treatment, the bacterial diversity significantly increased, whereas the presence of fungi had no significant difference following the B. subtilis K424 application. Moreover, B. subtilis K424 reduced the relative abundance of Actinomadura and promoted that of the Rhodanobacter, Bacillus, Pseudomonas, Devosiaceae, and Blastobotrys genera. Redundancy analysis showed that Bacillus, Rhodanobacter, and Blastobotrys were positively correlated with the substrate enzyme of sucrase, catalase, and urease. This study provides insight that B. subtilis K424 mitigated the deleterious effects of high levels of nutrition solution on cucumber growth and quality by improving the substrate enzyme, regulating the microbial community structure, and enhancing the photosynthetic capacity.

Microstructure and mechanical properties of Al-6.02Zn-1.94Mg alloy at higher solution treatment temperature

Microstructure and mechanical properties of Al-6.02Zn-1.94Mg alloy at higher solution treatment temperature

Attenuation of glycation and biochemical aberrations in fructose\u2010loaded rats by polyphenol\u2010rich ethyl acetate fraction of Parkia biglobosa (jacq.) Benth. (Mimosaceae) leaves

BackgroundDifferent parts of the Parkia biglobosa plant are employed in traditional medicine in different African communities. However, information ratifying its use and biochemical influence on health is still scanty in literature. Thus, the present study assessed the influence of the ethyl acetate fraction of Parkia biglobosa leaves (EAFPB) on some biochemical parameters of sub-chronic fructose-loaded rats.MethodologyTwenty-five Wistar rats were randomized into five groups (n = 5). The normal control group was maintained on normal diet only while the high fructose solution (HFS) control (placebo), reference and treatment groups received high fructose solution (3 g/kg/d b.w of fructose) for 30 days before treatment. Based on pilot study, two doses (100 and 200 mg/kg/d b.w) of EAFPB were selected and were administered to two groups of test animals while the reference group received 300 mg/kg/d b.w. of metformin for 14 days. Thereafter, blood was collected from fasted animals for biochemical analyses for the examination of level of glycated hemoglobin (HbA1c), liver status (alanine and aspartate aminotransferases (ALT and AST) and alkaline phosphatase (ALP) activities, and bilirubin level), lipid profile (total cholesterol, triglyceride, and low- and high-density lipoproteins levels) and lipid peroxidation (malondialdehyde – MDA level).ResultsEAFPB was shown to have a good DPPH radical scavenging activity (EC50 = 0.395 mg/ml). Chromatographic analysis of EAFPB revealed 28 known flavonoids (mainly kaempferol (21.31 mg/100 g), quercetin (12.84 mg/100 g), and luteolin (6.75 mg/100 g)), four hydrocinnamic acids derivatives (mainly P-coumaric acid (6.73 mg/100 g)), and 11 phenolic acids derivatives (mainly chlorogenic acid (48.18 mg/100 g) and protocatechuic acid (21.58 mg/100 g)). Relative to normal control, it was observed that fructose overload significantly increased serum activities of ALP, ALT, and AST, and levels of MDA, total cholesterol, low density lipoprotein and triglyceride in placebo. However, EAFPB significantly tapered the elevated serum activities of ALP, ALT, and AST. In addition, relative to placebo, the increased levels of HbA1c, MDA, and lipid health markers were also rebated by EAFPB.ConclusionsEthyl acetate fraction of Parkia biglobosa leaves attenuates biochemical aberrations in fructose-loaded rats, an effect attributable to the rich store of polyphenolic compounds in the fraction.Graphical abstract

Effect of solution treatment on the formability and part performance of IN718 sheet material

ABSTRACTIN718 sheets were separately solution treated to two different temperatures i.e. 970°C (HT970) and 1070°C (HT1070). Due to higher solution treatment temperature (1070°C), the microstructure altered considerably i.e. grain size increased, volume fraction of both strengthening phases () obliterated from the matrix (), and delta phase () dissolved. Further, both the heat-treated samples were deformed using limiting dome height (LDH) setup along different strain paths ranging from tension-compression to tension-tension deformation modes. It was observed that all the samples failed catastrophically without any significant hint of necking, and hence, fracture forming limit diagrams (FFLD) were estimated. It was found that the FFLD of HT1070 was marginally higher in comparison to that of HT970 material. The formability in terms of LDH, crack location and strain evolution for biaxially deformed cup was predicted successfully by finite element model incorporating Hills-48 plasticity theory. The results showed higher LDH with well-developed strain distribution in case of HT1070 material in comparison to that of HT970 material. However, the surface topography of biaxially stretched cup showed 116% increase in roughness for HT1070 material. The higher intensity of Brass and lower intensity of Cube components were responsible for higher surface roughness in case of HT1070 material.

Cold Bending a Ni-Ti Shape Memory Alloy Wire

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.

Solution Treatment and Aging (STA) Study of Ti Alloy Ti5Al3Mo1.5V

Titanium alloy Ti5Al3Mo1.5V is used in the fabrication of critical engine and pyro components for space applications. The alloy processed through double vacuum arc remelting and finish forged in α−β regime has been studied for its response to various heat treatments. Solution treatment and aging cycles have been varied to study their effect on tensile properties of the alloy. Response to solution treatment and aging is found to be significant in improving the mechanical properties. Specimens subjected to higher solution treatment temperatures (900 °C) i.e., Tβ-50 °C and higher aging temperature and time showed the highest strength with moderate ductility. It can be attributed to the presence of α’-phase and precipitation of fine secondary α. The presence of large amount of β-phase is noted through EBSD in the sample heat treated at higher temperature, which may also have precipitation of fine secondary α during aging at higher temperature and or for longer aging time.

Alteration of Solution Treatment Condition to the Precipitation Behavior A319 Alloy

The development of precipitate during ageing treatment of A319 alloy contributed significantly to the alloy strengthening mechanism. Two solution treatment temperatures which were set at 510°C and 525°C were subjected onto the different groups of A319 alloy samples and followed by artificial ageing process at 180°C. Scanning electron microscopy was employed to observe the over-aged samples from both solution treatment temperatures. The observation shows that Mg2Si precipitates was only appeared at the higher solution treatment condition, while the Al2Cu precipitate developed in both solution treatment temperatures.

Changes of γ′ precipitate characteristicsin damaged superalloy IN738LC during different stages of rejuvenation heattreatment cycles

The present study investigates the evolution of γ′precipitate microstructure in a creep damaged IN738LC superalloy during differentstages of rejuvenation heat treatment cycles. Dissolution of coarsened γ′precipitates in the creep damaged alloy occurred during different solutiontreatments. The precipitates that did not dissolve completely during solutiontreatment and those formed during subsequent cooling were considered to beas remnant and cooling precipitates respectively. It was found that highersolution treatment temperatures result in lower volume fraction of remnantprecipitates and further formation of cooling precipitates. Slower coolingrates after solution treatment gave the chance for the existing γ′particles to be coarser. Moreover, aging treatment increased the volume fractionof γ′ precipitates. Double solution treatment at1190°C/4 h/furnace cooling+1120°C/4 h/air cooling followed byaging at 845°C/24 h/air cooling dissolved nearly all the coarsened precipitatesand produced a new bimodal γ′ microstructure analogouswith that of the original alloy.

Zr-Containing Precipitates in Mg-3wt%Nd-0.2wt%Zn-0.4wt%Zr Alloy during Solution Treatment at 540°C

The microstructure of Mg-3wt%Nd-0.2wt%Zn-0.4wt%Zr (NZ30K) alloy after solution treatment was investigated and several kinds of interesting phases containing zirconium were found in this study. NZ30K was gravity cast using permanent die casting. After high tempering solution treatment at 540°C, cluster particles were observed inside the grains under optical microscopy. The detailed investigations were carried out on transmission electron microscopy (TEM). Four kinds of precipitates were visible inside grains with different shapes: block-like, globular, short rod-like, long rod-like. The block-like particle was identified as ZrH2 phase and the globular one was Zn2Zr3 phase. The other two were still Zr-containing phases, which could not be identified to any of existed compounds containing Zr. The formation of Zn-Zr compounds would probably be due to relative high ratio of Zr to Zn in the center of grains. ZrH2 would be the results of reaction of zirconium with H element during solution treatment, which probably came into the alloy during melting.

Effects of Zn addition to AuCu on age-hardening behaviors at intraoral temperature.

The effect of Zn addition to AuCu on the age-hardening rate at the intraoral temperature was investigated to find out the proper condition for high age-hardening rate. The increase in hardness of Zn-added alloys during aging at 37 degrees C was due to the atomic ordering. With an increase in Zn concentration, hardness of a sample under the as-quenched condition decreased, but the age-hardening rate obviously increased. When Zn content was fixed, a higher solution treatment temperature was more effective for the age-hardening at 37 degrees C. It was suggested that the formation energy of a vacancy considerably decreased with an increase in Zn content. It is reasonable to consider that the amount of quenched-in excess vacancies are markedly increased with an increase in Zn content when the solution treatment temperature was fixed. By transmission electron microscopic observations, it was revealed that the formation of the AuCu II superstructure contributed to the age-hardening at 37 degrees C in the high zinc content alloy.

Effect of solution treatment temperature on tensile properties of AI-7Si-O.3Mg (wt-%) alloy

The effect of solution treatment temperature on the tensile properties of an AI-7 Si-0.3Mg (wt-%) alloy has been studied using tensile and hardness testing, microprobe composition analysis, and differential scanning calorimetry. With a sufficiently long solution treatment time, an increase in solution treatment temperature from 500 to 560°C significantly increases the silicon content in the matrix, but has little effect on the magnesium content. This results in a slight increase in the peak aged yield strength, but a more significant increase in the peak aged ultimate tensile stress and hardness. The alloy ductility is independent of solution treatment temperature, but is clearly influenced by the degree of eutectic silicon particle spheroidisation and coarsening. Using a higher solution treatment temperature can shorten the solution treatment time required to achieve a given tensile elongation value.

Effect of silicon content on impact properties of austempered ductile iron

This study investigates the effect of austenitising temperature (850°C, 900°C, 950°C) and austempering time (0 to 7 h) on the impact energy values of three irons containing increasing silicon contents (2.02%, 2.65%, 3.31%) and around 0.3% manganese, austempered at 360°C. It was shown that increasing the silicon content modifies the Fe-C phase diagram such that (a) a higher solution treatment temperature is required to fully austenitise the iron, and (b) the resulting austenite dissolves less carbon. Increasing the austenitising temperature simultaneously with the silicon content restores a high carbon austenite, a fully ausferritic structure and high impact properties. On the other hand, the low silicon iron austenitised at 950°C results in a microstructure containing a continuous network of intercellular austenite. This is attributed to the manganese whose segregation is more evident in the iron containing 2.02% silicon. For a given silicon content, increasing the austenitising temperature increases the carbon content dissolved in the austenite which in turn reduces the free energy controlling the rate at which the austempering reaction proceeds. Either short or extensive holding in the austempering bath leads to undesirable structures and low mechanical properties. Intermediate austempering periods resulted in structures containing ferrite needles, a large volume of high carbon stable austenite and a better combination of mechanical properties.

Environmentally Assisted Cracking of Alloy X-750 in Simulated PWR Coolant

Abstract Environmentally assisted cracking (EAC) of different heat treatments of alloy X-750 has been studied in simulated pressurized water reactor (PWR) primary water from 50 to 340°C. The alloy, with single- (704°C/20 h) and two-stage (885°C/24 h + 704°C/20 h) aging treatments, was increasingly susceptible to EAC with decreasing temperature below ∼250°C. This susceptibility was due to hydrogen embrittlement, as indicated by the sensitivity to the hydrogen content of the water and behavior in hydrogen gas. At higher testing temperatures, a second mechanism, possibly anodic dissolution, was dominant for alloys with either a lower solution heat treatment temperature (980°C/1 h) or two-stage aging treatment. This second mechanism was suppressed by a higher temperature solution treatment (∼1100°C/1 h) and a single-stage aging treatment, which improved alloy performance.

A TEM study of discontinuous precipitation in Cu-Be alloys

It is known that a lamellar discontinuous precipitate forms in aged Cu-1.8wt.% Be alloys. The purpose of this study was to investigate factors which influence the formation of the precipitate and to characterize its growth.To determine the effect of solution treatment on the discontinuous precipitate, specimens were solution treated at 800°C, 850°C, and 900°C for 1 hour followed by an ice water quench. Some of the solution treated specimens were examined in the as-quenched condition. The remaining specimens were aged at 340°C for 24 hours. The specimens were thinned with a twin-jet electropolishing unit using 30% HNO3 in methanol at -60°C. The specimens were then examined using either an RCA-EMU3G or a Philips EM-300 electron microscope.Each solution treated specimen was not single phase, but showed some residual grain boundary precipitate which implies that the solution anneal was not sufficient, or else precipitation had occurred during quenching. The higher solution treatment temperatures slightly reduced the amount of this grain boundary precipitate, but none completely removed it, even after five hours at temperature,indicating quench decomposition as the mechanism responsible.

Tiにより安定化したステンレス鋼の組織とクリープ特性の関係について

It was frequently reported that Creep characteristics of stainless steel stabilized by titanium was strongly affected by its solution treatment. This report is also concerns with a study of this phenomena. It consists of two series of experiment: The first concerns with the changes in creep rate after heating at various temperature and the second proves the effect of solution treatment temperature on the creep rate after aging at 750°C. The first experiment shows that the creep rate does not increase by heating at a higher temperature than 900°C, but increases by heating at a lower temperature than 850°C. Refering to the previous report on the phase changes by heating at various temperatures, the increase in creep rate is concluded to be related to the precipitation of Cr3C2. The second experiment reveals that the precipitation of Cr3C2 is affected by the solution treatment temperature. In case of the lower solution temperature, the previously precipitated TiC accelerates the precipitations of Cr3C2. Consequently, the increase of the creep rate of the steel heated at a lower solution treatment temperature starts earlier than that at a higher solution treatment. Though it is sure that the precipitation of Cr3C2 is related to the deterioration of creep characteristics, but this might be the only sign of the phenomena and the direct proof is not given by this experiment.

18-8 Tiステンレス鋼の高温強度

A comprehensive study was carried out to investigate the effects of the chemical compositions, heat treatments and grain size on the creep rupture properties of the 18-8 Ti stainless steels, in wide use for superheater tubes and reheat tubes of power boilers. The conclusions are as follows:(1) Effect of chemical compositionsIt was found that the ferrite-free austenitic steels had the creep rupture strength superior to that with 14% ferrite at 550°C and 650°C, both of which had different compositions even though within the range of the specification (AISI 321 or JIS STB 42 D) and were obtainable to single or duplex structure by selection of proper composition also within the range of the specification.That is speculated to be attributable to occurrence of the precipitation of enormous chromium carbide around the ferrite in duplex austenite-ferrite structure at testing temperature.From these results, it is desirable as for the chemical compositions to offer fully austenitic structure, if possible, for elevated temperature applications. The results of measuring of the creep rupture strength of the 18-8 Ti steels within the range of 3 to 19 of Ti/C ratio, keeping the constant contents of carbon and other alloying elements, revealed that it increased with decrease of Ti/C ratio. It is assumed that increase of Ti/C ratio follows additional insoluble TiC at the prevalent solution treatment temperature (1100°C) and consequently decrease of TiC effective to creep rupture on the contrary, which precipitates finely and dispersedly into the austenite structure at service temperature. Thus it is recommendable to adopt low Ti/C ratio within the range of 3 to 7, to obtain high strength at elevated temperature.(2) Effect of heat treatmentsArising of the solution treatment temperature in the range of 1000°C to 1300°C brought about increase of the creep rupture strength of the steels. We might conclude, however, that to the temperature range of 1100°C to 1150°C is practically preferable, because too high temperature heat treatment bears low toughness.(3) Effects of grain sizeIt has generally been said that the coarsely grained steel has good creep rupture strengtth in comparison with that of the finely grained. However, in case of austenitic stainless steels, as creep rupture strength markedly depends on the condition of the precipitation of carbide along the grain boundaries at the service temperature range of 550°C to 650°C, it was found that the coarsely grained steel does not always show good creep rupture strength. Thus we may consider that the fact described in (2) is due not to the coarse grain but to the fine and uniform distribution of the precipitated carbide at service temperature, which shows the higher solubility to the matrix at higher solution treatment temperature.(4) Long-time creep rupture strengthCreep rupture tests up to 13000 hours are practised for advantageously heat-treated 18-8 Ti stainless steel with desirable chemical compositions. The extraporated 100000 hours rupture strength was 9.3kg/mm2. That is superior to the average value, 5.5kg/mm2, of ASTM STP No. 124. We may probably attribute that to underestimation of 18-8 Ti stainless steel, because the data of ASTM had been obtained before the relations between metallographic behaviors and creep rupture strength in this steel were satisfactorily clarified.