Stepwise Increase In Temperature Research Articles

Measuring Temperature Dependence of Entropy Via Temperature Ramps Using Float Current Analysis

Float current analysis is a long-term self-discharge experiment keeping the voltage (float voltage) constant and measuring the resulting current with high precision. After a transient phase lasting around 30 days, the current reaches a steady state, named float current (10.3390/en16093889).The float current reflects the self-discharge of a cell, after effects due to the oversized anode to the cathode (anode overhang effect) are concluded (10.1016/j.est.2018.04.029). In some publications, the float currents show strong correlation with the capacity loss rate (10.1016/j.jpowsour.2017.03.136, 10.3390/batteries7020022).To characterize the cells, the float current is measured while keeping the cell voltage constant and varying the temperature in steps or as a ramp. Changing the temperature leads, due to the entropy effect, to an increase or decrease of the cell voltage depending on the sign and magnitude of the entropy coefficient (10.1149/1945-7111/ac3938). As the voltage in our experiment is kept constant, one observes an additional positive or negative current resulting from changes in temperature. In a stepwise temperature approach, a waiting time of about 1 day must be considered until currents resulting from the steps temperature transient have subsided. To understand more about entropy, we used this dependence as will be rolled out in the following.For our experiment we investigated three different cell types of the format 18650 with varying cathode active materials (LFP, NMC, NCA) with up to five different float voltages. The cells were kept at constant voltage using a precision Keysight test bench in a Binder temperature chamber. The temperature was varied from 5 to 50°C using temperature ramps with rates of 0.56 K/h to 2.25 K/h. The results are compared to a stepwise temperature increase with 5 K increments.During ramp phases, we measure the float currents superimposed on the positive or negative influence of the entropy. By calculating the average of a temperature upwards ramp and a temperature downwards ramp, the entropy share is eliminated and only the pure temperature-dependence of the float current is obtained. The shape of the float current over temperature is an exponential increase, indicating an Arrhenius relation. As a homogeneous temperature change must be established, faster temperature ramps reveal strongly distorted transient-parts at the begin and end of the ramp, while a lower velocity shows only a very small transient-part. Comparing the low temperature velocities with stepwise approach, we observed a high agreement of both strategies demonstrating the validation of the temperature ramp approach.To obtain the entropy share during temperature ramps, the float current results are subtracted from the respective upwards and downwards ramps. Contradicting the general opinion of entropy for batteries, we did not observe a constant entropy coefficient over temperature but an entropy coefficient increasing linearly with temperature for all cell types and cell voltages. This finding is of high importance for high-precision measurement of lithium-ion batteries. Figure 1

Sequential loss-on-ignition as a simple method for evaluating the stability of soil organic matter under actual environmental conditions

Soil organic matter (SOM) is one of the largest carbon (C) reservoirs on Earth, and therefore its stability attracts a great deal of interest from the perspective of the global C cycle. This study examined the applicability of loss-on-ignition with a stepwise increase in temperature (SIT-LOI) of soil to evaluate the stability of SOM using soil samples having different organic matter (OM) and mineral contents and different mean residence times (MRTs) for SOM. The responses of SOM to the SIT-LOI varied depending on the samples but were all successfully approximated by a liner regression model as a function of the temperature of LOI. The slope value in the liner model that determines the residual potential of carbon during the SIT-LOI highly correlated with MRT of SOM, suggesting that this value reflects the overall stability of SOM over a range of soil properties. This hypothesis was consistent with the observation that Δ14C values of SOM decreased with increasing LOI temperature and thus, older, slower-cycling SOM was preferentially left in the soil samples by SIT-LOI. Additionally, the hypothesis was also supported by the significant correlations (p < 0.01) between the slope value and OM and mineral contents in the samples because these components are considered to regulate SOM stability. In addition to the regression analysis of the SIT-LOI data, changes in carbon to nitrogen (C/N) and carbon to hydrogen (C/H) ratios and stable carbon isotope signatures (δ13C) of the samples were investigated. The results suggest that the mineral association of SOM is an important factor characterizing the response of SOM to LOI. Hence, it was concluded that SIT-LOI is a simple and useful method for evaluating the stability of SOM under actual environmental conditions.

Physiological response of Symbiodiniaceae to thermal stress: Reactive oxygen species, photosynthesis, and relative cell size.

This study investigates the physiological response to heat stress of three genetically different Symbiodiniaceae strains isolated from the scleractinian coral Mussismilia braziliensis, endemic of the Abrolhos Bank, Brazil. Cultures of two Symbiodinium sp. and one Cladocopium sp. were exposed to a stepwise increase in temperature (2°C every second day) ranging from 26°C (modal temperature in Abrolhos) to 32°C (just above the maximum temperature registered in Abrolhos during the third global bleaching event-TGBE). After the cultures reached their final testing temperature, reactive oxygen species (ROS) production, single cell attributes (relative cell size and chlorophyll fluorescence), and photosynthetic efficiency (effective (Y(II)) and maximum (Fv/Fm) quantum yields) were measured within 4 h and 72 h. Non-photochemical coefficient (NPQ) was estimated based on fluorescence values. Population average ROS production was variable across strains and exposure times, reaching up a 2-fold increase at 32°C in one of the Symbiodinium sp. strains. A marked intrapopulation difference was observed in ROS production, with 5 to 25% of the cells producing up to 10 times more than the population average, highlighting the importance of single cell approaches to assess population physiology. Average cell size increases at higher temperatures, likely resulting from cell cycle arrest, whereas chlorophyll fluorescence decreased, especially in 4 h, indicating a photoacclimation response. The conditions tested do not seem to have elicited loss of photosynthetic efficiency nor the activation of non-photochemical mechanisms in the cells. Our results unveiled a generalized thermotolerance in three Symbiodiniaceae strains originated from Abrolhos' corals. Inter and intra-specific variability could be detected, likely reflecting the genetic differences among the strains.

The Energy Characteristics of the Surface of Statistical Copolymers.

The results of systematic studies on the surface energy γ and its polar γP and dispersion γD components of statistical copolymers of styrene and butadiene, acrylonitrile and butadiene, and butyl acrylate and vinyl acetate, with regard to their thermal prehistory, are generalized. Along with copolymers, the surfaces of their composing homopolymers were examined. We obtained the energy characteristics of the adhesive surfaces of copolymers that contacted with air, high-energy aluminium Al (γ = 160 mJ/m2), and the low-energy substrate surface of polytetrafluoroethylene F4 (PTFE) (γ = 18 mJ/m2). The surfaces of copolymers in contact with air, aluminium, and PTFE were investigated for the first time. It was found that the surface energy of these copolymers tended to occupy an intermediate value between the surface energy of the homopolymers. The additive nature of the change in the surface energy of the copolymers with their composition, as previously established in the works of Wu, extends to the dispersive component of the free surface energy γD and the critical surface energy γcr, according to Zisman. It was shown that a significant influence on the adhesive activity of copolymers was exerted by the substrate surface upon which the adhesive was formed. Thus, for the butadiene-nitrile copolymer (BNC) samples formed in contact with a high-energy substrate, their surface energy growth was associated with a significant increase in the polar component of the surface energy γP from 2 mJ/m2 for the samples formed in contact with air, to an increase from 10 to 11 mJ/m2 for the samples formed in contact with Al. The reason why the interface influenced the change in the energy characteristics of the adhesives was the selective interaction of each macromolecule fragment with the active centres of the substrate surface. As a result, the composition of the boundary layer changed and it became enriched with one of the components. The structure of such layers is nonequilibrium. The thermal annealing of copolymers in the mode of a stepwise temperature increase led to a convergence in the values of γ, asymptotically tending to the value characteristic of the surface of the copolymers formed in air. The activation energies for the processes of the conformational rearrangements of the macromolecules in the surface layers of the copolymers were calculated. It was found that the conformational rearrangements of the macromolecules in the surface layers occurred as a result of the internal rotation of the functional groups that determined the polar component of the surface energy.

Invasive upside-down jellyfish tolerate organic eutrophication and warming

The upside-down jellyfish Cassiopea is a successful invasive organism due to high tolerance of different environmental conditions. So far, some single local or global factor experiments have been conducted to assess the effect on the ecophysiology of Cassiopea, but information about combined factor effects is scarce. Therefore, we performed a 42-d manipulation experiment exposing Cassiopea sp. to a local (organic eutrophication) and global factor (warming) simultaneously, i.e., four different dissolved organic carbon (DOC) concentrations [3 (Control), 10 (Low), 20 (Medium) and 40 (High) mg L–1], followed by a stepwise water temperature increase from 26 to 32 °C, in which we assessed four ecophysiological parameters: respiration, net photosynthesis, gross photosynthesis, and pumping rate. Our results show a steep increase in respiration and simultaneous decline in gross photosynthesis in response to Medium and High DOC enrichment causing medusae in the respective treatments to become net heterotrophic over time. This was accompanied by increases in pumping rates, likely to optimize gas exchange and potentially increase nutrient availability by advection of nutrients trapped in underlying sediments. No effect of warming was found for any of the assessed parameters. The observed transition from auto- to heterotrophy under high DOC concentrations together with the thermal tolerance of Cassiopea sp. aids to understand the current invasive success of members of the genus Cassiopea as nonnative organisms and may shed light on the future of Cassiopea sp. as potential native invaders.

Antibiotic-Induced Treatments Reveal Stress-Responsive Gene Expression in the Endangered Lichen Lobaria pulmonaria

Antibiotics are primarily found in the environment due to human activity, which has been reported to influence the structure of biotic communities and the ecological functions of soil and water ecosystems. Nonetheless, their effects in other terrestrial ecosystems have not been well studied. As a result of oxidative stress in organisms exposed to high levels of antibiotics, genotoxicity can lead to DNA damage and, potentially, cell death. In addition, in symbiotic organisms, removal of the associated microbiome by antibiotic treatment has been observed to have a big impact on the host, e.g., corals. The lung lichen Lobaria pulmonaria has more than 800 associated bacterial species, a microbiome which has been hypothesized to increase the lichen’s fitness. We artificially exposed samples of L. pulmonaria to antibiotics and a stepwise temperature increase to determine the relative effects of antibiotic treatments vs. temperature on the mycobiont and photobiont gene expression and the viability and on the community structure of the lichen-associated bacteria. We found that the mycobiont and photobiont highly reacted to different antibiotics, independently of temperature exposure. We did not find major differences in bacterial community composition or alpha diversity between antibiotic treatments and controls. For these reasons, the upregulation of stress-related genes in antibiotic-treated samples could be caused by genotoxicity in L. pulmonaria and its photobiont caused by exposure to antibiotics, and the observed stress responses are reactions of the symbiotic partners to reduce damage to their cells. Our study is of great interest for the community of researchers studying symbiotic organisms as it represents one of the first steps to understanding gene expression in an endangered lichen in response to exposure to toxic environments, along with dynamics in its associated bacterial communities.

Structure evolution and charge hysteresis in buried Hafnia-Alumina oxides

Analysis of the high-k buried oxide phase evolution by the X-ray study, pseudo-MOSFET and CV measurements was used to separate the ferroelectric and interface dipole polarization, and charge trapping up to 300 °C. The thermal budgets during the rapid thermal annealing (RTA) 30 s at temperatures 600 to 1000 °C were established for different hafnia based stacks to ensure the recrystallization of HfO2 layers and preservation of ferroelectric hysteresis. The highest hysteresis was obtained at the RTA stepwise temperature increase to 900 °C for the stack with supercicles HfO2:Al2O3 (10:1).

Исследование высокотемпературной гомогенизации монокристаллического никелевого жаропрочного сплава 3-го поколения

High-alloyed nickel-based superalloys used for casting of single crystal blades of aircraft gas-turbine engines have to be subjected to a long-term high-temperature homogenization annealing for dissolution of nonequilibrium γ′-eutectics and smoothing of dendritic segregation of alloying elements. Single crystal nickel-based superalloy of the 3-rd generation CMSX-10 developed by Cannon-Muskegon corporation for casting highly loaded uncooled single crystal blades of the first stage of a high pressure turbine of an aviation gas turbine engine Trent 800 belongs to such alloys. In the present work, the processes occurring during high-temperature homogenization annealing of this alloy have been investigated. It is shown that the kinetics of dissolution of nonequilibrium γ′-eutectics strongly depends on temperature: in the range of 1340 – 1360 °C the dissolution rate increases by about an order of magnitude with increasing temperature by 10 °C. Two types of homogenization annealing with a stepwise increase of temperature proposed for CMSX-10 by Cannon-Muskegon have been investigated: a long 45-hour annealing with 10 steps of temperature increase and a shortened 20-hour annealing with 6 temperature steps. The change in the solidus temperature of the alloy during the homogenization was studied by the method of measurement of the specific electrical resistance. It is shown, that during homogenization annealing of the both types the nonequilibrium eutectics is completely dissolved, and a longer 45-hour annealing provides a deeper chemical homogenization of the alloy. This is especially important for such alloying element as rhenium, which has a high segregation coefficient and very slow diffusion mobility in nickel. Deeper homogenization provides better thermal stability of the alloy microstructure and consequently higher long-term creep strength. A negative effect of high-temperature homogenization is increased porosity resulting from the dissolution of γ′-eutectics. Homogenization porosity can be reduced by optimizing the alloy composition and reducing the fraction of nonequilibrium γ′-eutectics.

Effect of heat load on pneumatic temperature control characteristics of a pressure-controlled loop heat pipe

The effect of the supplied heat load on the operating characteristics of the pneumatic temperature control technique was systematically investigated. A pressure-controlled loop heat pipe employing water as a working fluid was designed and constructed to provide a unique thermohydraulic linkage between temperature and pressure. The temperature of the high-speed vapor was precisely controlled by using helium (control gas) to actively control the compensation chamber pressure; the stability of the pneumatically controlled temperature was approximately 0.01 °C regardless of the heat load. Stable stepwise temperature increase was attained below a critical pressure step that rose with increasing heat load. This behavior implied that a stable range of pneumatic temperature control became larger with increasing heat load. In addition, the maximum pressurization rate for rapid, stable, and unlimited temperature rise increased with increasing heat load. The uniformity of the controlled temperature field was less than approximately 0.2 °C over 25 cm; effects of the heat load were insignificant at all tested conditions. Overall, pneumatic temperature control over extended pressure and temperature ranges was attained at higher heat loads with insignificant effects of the heat load on stability and uniformity.

Maillard Browning Inhibition by Ellagic Acid via Its Adduct Formation with the Amadori Rearrangement Product.

The Maillard reaction performed under a stepwise increase of temperature was applied for researching the inhibition of Maillard browning caused by ellagic acid. Ellagic acid was found effective for the inhibition of melanoidin formation in the xylose-glycine Maillard reaction but depended on its dosage and the point of time it was added in the reaction system. The lightest color of the Maillard reaction products was observed when ellagic acid was added at the 90th min, which was the point of time when the Amadori rearrangement product (ARP) developed the most. LC-ESI-MS/MS analysis results showed a significant tendency of the ellagic acid hydrolysis product to react with the predominant intermediate ARP to yield an adduct. The adduct stabilized the ARP and delayed its decomposition and inhibited the downstream reactions toward browning. After the ARP was depleted, ellagic acid also showed an effect on scavenging some short-chain dicarbonyls which contributed to the inhibition of Maillard browning.

Process Performance and Microbial Community Variation in High-Rate Anaerobic Continuous Stirred Tank Reactor Treating Palm Oil Mill Effluent at Temperatures Between 55 and 70 °C

Palm oil mill effluent (POME) is wastewater that is generated from the extraction of oil from palm fruit and palm kernels and is discharged at a relatively high temperature (80–90 °C). Anaerobic digestion (AD) of POME has been mostly investigated at a mesophilic range of temperatures (30–38 °C) and at a thermophilic temperature of 55 °C. The thermophilic AD of POME at higher temperatures could be advantageous as treatment at thermophilic temperatures may increase rates of biochemical reactions. Stepwise temperature increase is a methodology for adaptation of microorganisms to higher temperatures. In this study, the effects of stepwise temperature increments of 5 °C from 55 to 70 °C on the AD of POME were investigated in a continuous stirred tank reactor (CSTR) operated under high organic loading rates (OLRs). The process performance and microbial community structure at each temperature interval were evaluated. It was observed that the methane production rates of the CSTR increased with increasing OLRs up to values of 13.7 g/L days, 25.7 g/L days, and 26.5 g/L days at operating temperatures of 55 °C, 60 °C, and 65 °C, respectively. As a result of the increasing OLRs, the maximum rate of methane production increased from 3.8 L/L days at 55 °C to 4.4 L/L days at 60 °C. The microbial community structure analysis showed that there were notable reductions in the gene copy number of the bacterial domain and the Methanosarcinales order with increasing temperatures from 55 to 60 °C and to 65 °C, whereas hydrogenotrophic methanogens, especially the genus Methanobacterium, in the order Methanobacteriales became dominant at 60 °C and 65 °C. Thus, the methanogenesis pathway was suggested to be a combination of acetoclastic and hydrogenotrophic methanogenesis at 55 °C and 60 °C with an increased contribution of hydrogenotrophic methanogenesis at 60 °C, whereas methane was mainly generated via hydrogenotrophic methanogenesis at 65 °C. The thermophilic AD of POME at 60 °C was found to be promising because the methane content in the biogas and the methane production rates were optimal, with an average methane content of approximately 73%.

Effect of Pressure and Temperature on Microstructure of Self-Assembled Gradient AlxTi1−xN Coatings

The correlation between structural properties of Al-rich self-assembled nano-lamellar AlxTi1−xN coatings and process parameters used during their chemical vapor deposition (CVD) remains unexplored. For this article, two gradient AlxTi1−xN coatings were prepared by a stepwise increase in temperature and pressure in the ranges of 750–860 °C and 1.56 to 4.5 kPa during the depositions at a constant composition of the process gas mixture. The cross-sectional properties of the coatings were analyzed using X-ray nanodiffraction (CSnanoXRD) and electron microscopy. Experimental results indicate that the variation of the process parameters results in changes in microstructure, grain morphology, elastic strain, nanolamellae’s chemistry and bi-layer period. At temperatures of ~750–800 °C and pressures of 2.5–4.5 kPa, preferably cubic nanolamellar grains are formed, whose microstructure correlates with the build-up of tensile stresses, which become relaxed in coating regions filled with nanocrystalline grains. CSnanoXRD superlattice satellite reflections indicate the period of the cubic Al(Ti)N-Ti(Al)N bilayers, which changes from 6.7 to 9 nm due to the temperature increase from 750 to ~810 °C, while it remains nearly unaffected by the pressure variation. In summary, our study documents that CVD process parameters can be used to tune microstructural properties of self-assembled AlxTi1−xN nanolamellae as well as the coatings’ grain morphology.

АППАРАТУРНОЕ ОФОРМЛЕНИЕ И РЕЖИМНЫЕ ПАРАМЕТРЫ ПРОЦЕССА БЛОЧНОЙ ПОЛИМЕРИЗАЦИИ ИЗОПРЕНА

The stationary bed type regimes of apparatuses for catalytic isoprene polymerization process in bulk are investigated. If the polymerization process is performed with the bed height equal to 3 mm, the thermal apparatus regime is close to isothermic one. The increase of the bed height up to 6 mm makes the apparatus regime wide of the mark. To remove the lack there is proposed the regime providing the one time stepwise increase of the wall apparatus temperature. Due to proposed regime the apparatus efficiency makes gain while polymerization is performed up to incomplete conversions

Temperature Stratification and Monochromatic Light Break Dormancy and Facilitate On-Demand In Situ Germination in the Seagrass Halophila ovalis, with Seed Viability Determined by a Novel X-Ray Analysis

The seagrass Halophila ovalis rapidly colonizes marine sediments from seed across a range of depth, light, and temperature conditions, making it ideal for restoration projects. Yet, presently, it is not a targeted restoration species as the biology of seed dormancy and germination is poorly understood. This study addresses that knowledge gap by experimenting with temperature and light pre-treatments with the aim to determine optimal conditions for high rates of seed germination. H. ovalis seeds were pre-treated ex situ by applying nine combinations of temperature and monochromatic light. Two thirds of the pre-treated seeds were placed at separate field sites in conditions suboptimal for natural germination while one third remained in ex situ culture under suboptimal germination conditions (17 °C). Seed viability was monitored to determine if storage conditions impacted viability. X-ray analysis revealed a general decline in viability with time in storage. To analyze the effectiveness of pre-treatments, we compared the results of ex situ and in situ germination. Pre-treating seeds with red light (673 nm) and a stepwise temperature increase (15–20–25 °C) yielded the highest germination success across field and laboratory culture conditions. This indicates that we can use temperature and monochromatic light pre-treatments to break seed dormancy in the laboratory and induce “on-demand” germination of seeds after delivery to field sites potentially leading to more efficient and successful restoration practices with this species. Similarly, the conditions required for breaking dormancy and germination in H. ovalis (red spectrum light and a stepwise temperature increase) represent conditions associated with spring river freshwater runoff and warming of estuaries and coastal seas in temperate Australia.

Effects of Water Content and Temperature on Bulk Resistivity of Hybrid Cement/Carbon Nanofiber Composites.

Cement nanocomposites with carbon nanofibers (CNFs) are electrically conductive and sensitive to mechanical loads. These features make them useful for sensing applications. The conductive and load sensing properties are well known to be dependent on carbon nanofiber content; however, much less is known about how the conductivity of hybrid cement–CNF depend on other parameters (e.g., water to cement ratio (w/c), water saturation of pore spaces and temperatures above ambient temperature). In this paper we fill-in these knowledge gaps by: (1) determining a relationship between the cement–CNF bulk resistivity and w/c ratio; (2) determining the effect of water present in the pores on bulk resistivity; (3) describing the resistivity changes upon temperature changes up to 180 °C. Our results show that the increase in the water to cement ratio results in increased bulk resistivity. The decrease in nanocomposite resistivity upon a stepwise temperature increase up to 180 °C was found to be related to free water release from cement pores and the dry materials were relatively insensitive to temperature changes. The re-saturation of pores with water was not reversible with respect to electrical resistivity. The results also suggest that the change in the type of electrical connection can lead to two orders of magnitude different bulk resistivity results for the same material. It is expected that the findings from this paper will contribute to application of cement–CNF-based sensors at temperatures higher than ambient temperature.

Characterizing the effects of thermal treatment on human norovirus GII.4 viability using propidium monoazide combined with RT-qPCR and quality assessments in mussels

This study investigated the effects of thermal treatment (70, 80, and 90 °C for 5, 10, and 20 min) on the titers of human norovirus (HuNoV) GII.4, a dominant genotype in fresh mussels using propidium monoazide (PMA) pretreatment and real-time reverse transcription quantitative-polymerase chain reaction (RT-qPCR) and the effects of thermal treatment on mussel quality (Hunter colors and sensory properties). Reductions of >1-log10 for HuNoV in PMA-treated mussels required 70 °C for 20 min, 80 °C for 10 min and 90 °C for 5 min. As assessed by PMA/RT-qPCR, the log10 reduction values of HuNoV in PMA-treated samples was significantly reduced (46% or 0.27 log10; P < 0.05) when heated to 90 °C for 20 min compared with non-PMA treated samples under identical conditions. Hunter color ‘L’-, and ‘a’- and ‘b’- values significantly (P < 0.05) decreased and increased, respectively with a stepwise increase of temperature (70–90 °C) and duration of heat treatment (5–20 min). The results of the untrained 7-point hedonic scale of sensory evaluation revealed that mussels heated to 90 °C for 10 min were the best quality sample among all thermally treated mussels. The results suggest that the PMA/RT-qPCR method could be very effective in distinguishing HuNoV viability following high heat treatment for an extended duration (eg, 90 °C for 20 min). Based on these results, the PMA/RT-qPCR method could be very effective in assessing HuNoV viability following high-heat treatment for an extended duration (eg, 90 °C for 20 min). Furthermore, our findings suggest that inactivation of HuNoV GII.4 in the bivalve molluscan shellfish may be accomplished by treatment at 70 °C for 20 min, 80 °C for 10 min, or 90 °C for 5 min. Among all thermal treatments, 90 °C for 10 min was considered the optimal cooking temperature and duration for mussels.

Effect of microwave decomposition on inductively coupled plasma spectrometry analysis of minerals in oysters

Oysters, which can be cultivated in oceans, are rich in nutrients. Recently, our group has reported the rapid analysis of multiple minerals in Crassostrea gigas oysters by employing microwave decomposition combined with inductively coupled plasma atomic emission spectrometry (ICP-AES). In this study, different oysters (e.g., Crassostrea nippona) were used, and calcium, potassium, sodium, and magnesium contents were estimated by microwave digestion using nitric acid and hydrogen peroxide. The addition of nitric acid with a stepwise increase in the microwave decomposition temperature to 230 °C led to the effective estimation of multiple minerals. The potassium content was estimated by the mere addition of acids to the oyster sample for ICP-AES analysis. These results can be possibly beneficial for the analysis of other creatures and foods including the choice of the location in the oceans at which oysters can be grown for the purpose of increasing food production in future.

Interaction of Added l-Cysteine with 2-Threityl-thiazolidine-4-carboxylic Acid Derived from the Xylose-Cysteine System Affecting Its Maillard Browning.

The Maillard reaction under a stepwise increase of temperature using l-cysteine as the indicator was performed to determine the formation conditions for the preparation of 2-threityl-thiazolidine-4-carboxylic acid (TTCA) which was the main Maillard reaction intermediate (MRI) derived from the xylose (Xyl)-cysteine (Cys) model system in aqueous medium. To clarify the indicating mechanism of Cys for the TTCA formation, the thermal model systems of TTCA-Cys and TTCA solutions were investigated. The browning of the final Maillard reaction products (MRPs) and concentration of downstream degradation products of MRIs indicated that the added Cys could react with TTCA to inhibit the formation of visible color via preventing the generation of dicarbonyl compounds derived from MRIs. Through HPLC analysis, it was demonstrated that added Cys affected the normal reaction pathway from TTCA to ARP and other downstream products by restoring TTCA to sugar and amino acid under heat treatment.

Long-term corrosion behaviour of carbon steel and stainless steel in Opalinus clay: influence of stepwise temperature increase

ABSTRACTCarbon steel (C-steel; E24 and S235 grades) and stainless steel (316L) electrodes were corroded in situ in Opalinus clay under anoxic conditions in a vertical descending borehole. The electrodes were exposed at ambient temperature for two years, and then at 85°C for five years. In situ electrochemical impedance spectroscopy showed that the instantaneous corrosion rate of C-steel decreased over time down to 1 µm year−1, followed by steady state. Microbial and chemical investigations showed that sulphate and thiosulphate reducing prokaryotes were present in the porewater and at the metal surface. Post mortem characterisation revealed contrasting corrosion aspects. The E24 corrosion interface was thick and contained magnetite, mackinawite, hydroxychloride and siderite, together with more oxidised species (goethite, greigite, elemental sulphur). The S235 corrosion interface was thinner and contained siderite and mackinawite. Corrosion damage of the 316L electrode was negligible, and the surface was covered by a thin fringe of pyrite.

Timely Addition of Glutathione for Its Interaction with Deoxypentosone To Inhibit the Aqueous Maillard Reaction and Browning of Glycylglycine-Arabinose System.

The inhibitory effects of glutathione (GSH) and oxiglutathione (GSSG) on Maillard browning were compared, and it was clarified that free sulfhydryl was the key substance for the inhibition. The Amadori rearrangement product (ARP) derived from glycylglycine (Gly-Gly) and arabinose (Ara) was prepared by aqueous Maillard reaction, and LC-MS/MS was used to investigate the reaction products of GSH and purified ARP. Reaction between GSH and deoxypentosone (DP) was found to alter the pathway of aqueous Maillard reaction, which reduced the production of glyoxal, methylglyoxal, and furfural and thereby inhibited the formation of melanoidins. To determine the optimal conditions for browning inhibition, a stepwise increase of temperature was used to prepare Maillard reaction products (MRPs). The results showed that the optimum browning inhibitory effect was obtained by adding GSH after Gly-Gly and Ara heating at 80 °C for 60 min.