Accelerated VS Natural Aging: Effect of Aging Conditions on the Aging Process of Cellulose

1995 ◽  
Vol 352 ◽  
Author(s):  
David Erhardt ◽  
Marion F. Mecklenburg
2021 ◽  
Vol 233 ◽  
pp. 02043
Author(s):  
Hongjun Ni ◽  
Kaixuan Wang ◽  
Qijun Shi ◽  
Shuaishuai Lv ◽  
Yonglan Liu ◽  
...  

Rice wine is a kind of low alcohol and high nutrition four season drinking wine made from water and glutinous rice. Generally, new rice wine needs to undergo a natural aging process for about 1 year. In order to solve the problems of long natural aging period and poor aging effect of rice wine, a set of rice wine aging device was designed and a comprehensive method was used to age the rice wine. By orthogonal experiments, the optimal aging process parameters were determined, which were temperature 55 °C, aging time 12 days, and hydrogen peroxide addition 4 mL/200 mL. The results show that the content of ethyl acetate and ethyl lactate in rice wine are 0.44 g/L and 0.80 g/L respectively and the content of total acid and total sugar reaches 6.9 g/L and 230.2 g/L respectively. Compared with naturally aged rice wine, it is verified that the effect of artificial aging can achieve the effect of natural aging for one year. This experiment provides a new method for the study of artificial aging of rice wine.


2016 ◽  
Vol 44 (04) ◽  
pp. 803-815 ◽  
Author(s):  
Lin Bai ◽  
Guiying Shi ◽  
Yajun Yang ◽  
Wei Chen ◽  
Lianfeng Zhang

Anti-aging has always been a popular topic, and there are many claims about the existence of factors that can slow, stop, or even reverse the aging process. Siraitia grosuenorii, a local fruit in china, has been used for the treatment of gastritis, sore throats, and whooping cough in traditional Chinese medicine. The individuals who took the juice of Siraitia grosuenorii regularly had increased longevity in the Guangxi Province, which is located in the Southern part of China. In this paper, we fed mice with Siraitia grosuenorii for 10 months to identify the role of Siraitia grosuenorii in anti-aging and to investigate its corresponding mechanism. The results showed that mice fed with Siraitia grosuenorii displayed a slower aging process. The extension of the aging process was due to the enhanced function of HSCs. FACS analysis showed that the number of LSKs, LT-HSCs, ST-HSCs and MPPs from Siraitia grosuenorii mice was decreased. In vitro, a clonigenic assay showed that LT-HSCs from Siraitia grosuenorii mice increased the ability of self-renewal. Moreover, Siraitia grosuenorii mice maintained the quiescence of LSKs, decreased the level of ROS and reduced the amount of senescence associated β-gal positive cells. Furthermore, Siraitia grosuenorii mice decreased the expression of senescence-associated proteins. Siraitia grosuenorii maintained quiescence, decreased senescence and enhanced the function of HSCs, slowing the aging process of mice.


2020 ◽  
Vol 29 (54) ◽  
pp. e10514
Author(s):  
Beatriz García-Castellanos ◽  
Osney Pérez-Ones ◽  
Lourdes Zumalacárregui-de-Cárdenas ◽  
Idania Blanco-Carvajal ◽  
Luis Eduardo López-de-la-Maza

The rum aging process shows volume losses, called wastage. The numerical operation variables: product, boardwalk, horizontal and vertical positions, date, volume, alcoholic degree, temperature, humidity and aging time, recorded in databases, contain valuable information to study the process. MATLAB 2017 software was used to estimate volume losses. In the modeling of the rum aging process, the multilayer perceptron neuronal network with one and two hidden layers was used, varying the number of neurons in these between 4 and 10. The Levenberg-Marquadt (LM) and Bayesian training algorithms were compared (Bay) The increase in 6 consecutive iterations of the validation error and 1,000 as the maximum number of training cycles were the criteria used to stop the training. The input variables to the network were: numerical month, volume, temperature, humidity, initial alcoholic degree and aging time, while the output variable was wastage. 546 pairs of input/output data were processed. The statistical Friedman and Wilcoxon tests were performed to select the best neural architecture according to the mean square error (MSE) criteria. The selected topology has a 6-4-4-1 structure, with an MSE of 2.1∙10-3 and a correlation factor (R) with experimental data of 0.9898. The neural network obtained was used to simulate thirteen initial aging conditions that were not used for training and validation, detecting a coefficient of determination (R2) of 0.9961.


2000 ◽  
Author(s):  
T. Jesse Lim ◽  
Wei-Yang Lu

Abstract In this work, uniaxial tensile testing of a 63Sn-37Pb alloy with different specimen sizes and aging conditions had been carried out. Although the stress-strain responses of different specimen sizes and aging conditions differs, the ultimate strength of the specimens with 16 hours, 100°C aging are similar for the sizes tested. The specimens with 25 days, 100°C aging have different stress-strain response with different sizes, and have a lower ultimate strength and higher failure strain compared to 16 hours, 100°C aging specimens.


2021 ◽  
Author(s):  
Ferhat Ege

Osteoarthritis (OA) is a condition with high prevalence worldwide. OA affects not only the articular cartilage, but the entire joint, including the subchondral bone, ligaments, capsule, synovial membrane and the periarticular muscles. Despite the fact that the risks associated with OA increase with age, it is not a part of the natural aging process. It typically involves the knee, hip, spine, hand and foot joints. Several factors play an important role in the pathogenesis of OA, including biomechanical factors, proinflammatory mediators and proteases. On the other hand, it was mostly the results of the studies conducted on the genetic, genomic and epigenetic aspects of OA, from among many of its underlying etiological factors, which shed light on the molecular processes involved in the etiopathogenesis of OA. As the mechanisms that cause joint tissue damage in OA come to light, the treatment of OA will go beyond just providing symptomatic relief. Consequentially, new treatments will emerge that will either slow or completely stop the progression of OA.


2016 ◽  
Vol 723 ◽  
pp. 27-31
Author(s):  
Ines Hamdi ◽  
Zakaria Boumerzoug

The precipitation sequence of an Al-Mg-Si alloy depends on many parameters. In this study the natural aging effect on the activation energy of the precipitation sequence in the Al-Mg-Si alloy have been investigated by differential scanning calorimetry (DSC). The precipitation sequence of an Al-Mg-Si alloy has been established. The activation energy of the precipitation process was calculated using Kissinger model. The results obtained using this method showed a change in the activation energy for all precipitated phases. The activation energy of the metastable phases (β″ and β′) and the stable phase β formation in the Al-Mg-Si alloy aged at room temperature have been determined.


2018 ◽  
Vol 941 ◽  
pp. 1155-1160
Author(s):  
Ying Li ◽  
Zhi Qiang Zhang ◽  
Jian Liu ◽  
Hua Yin ◽  
Chang Shu He

A heat treatable A7N01 (Al-Zn-Mg) aluminum alloy mainly used to fabricate high-speed train body structures was double-sided welded by MIG welding. The natural aging behavior of the joint was systematically studied by local and global mechanical property testing method. Based on TEM observation and EPMA analysis, the key factors that lead to different natural aging behavior among various regions of the joint were discussed. The global tensile strength of the joints increased obviously after natural aging. All the joint samples fractured in the weld zone, which demonstrated the weld zone was the weakest zone of the joints. And the strength of the global welds were depended on the microstructure and natural aging ability of the weld zone. Moreover, the increase of the tensile property of the three local regions in the weld zone after post natural aging decreased as Middle>lower>upper. The above phenomenon was also further confirmed by microhardness measurement. The age hardening behavior is greatly influenced by the concentration of strengthening precipitates forming element Zn. The Zn content in the weld zone determined by EPMA showed that element Zn was dispersed unevenly, which is attributed to the double V-groove design used in this work and Zn vaporization in the molten pool during welding. The Zn content in the middle layer metals is higher than that of the upper and lower layers, resulting in the remarkable hardening response for the middle layer of the weld zone during natural aging process. Additionally, the solution zone containing the same Zn content as the base metal and undergoing sufficient solid solution during welding was found to possess the high hardening ability after natural aging process.


2017 ◽  
Vol 14 (6) ◽  
pp. 394 ◽  
Author(s):  
Nicole Bandow ◽  
Verena Will ◽  
Volker Wachtendorf ◽  
Franz-Georg Simon

Environmental contextIncreasing global plastic production adds plastic debris to the environment. We show that potentially harmful additives present in plastic particles are released to water at an increased rate when material properties change by aging due to exposure to high temperature and especially to UV radiation. For risk assessment of such plastic additives, more information on their degradation products and their toxicity is needed. AbstractRecycled plastic granules of high-density polyethylene, polyvinyl chloride and polystyrene the size of microplastics were exposed to artificial aging conditions (2000h; photooxidative and thermo-oxidative) to simulate their fate outdoors. Their potential to leach into water during the aging process was investigated using column percolation tests. Aging-related changes on the surface of the material were characterised by IR measurements indicating oxidation reactions with the formation of new adsorption bands (C=O, C–O and OH), especially in the case of photooxidative aging. These findings were confirmed by the identification of leachable organic compounds. Leaching of total organic carbon, Cl, Ca, Cu and Zn is clearly affected by changes due to aging, and their release is increased after photooxidative aging. In general, exposure to photooxidative conditions shows a greater influence on aging and thus on leaching and seems to be the more important mechanism for the aging of microplastic in the environment. Comparison with the total content of inorganic species revealed that, for most elements, less than 3% of the total content is released after 2000h of photooxidative aging.


1947 ◽  
Vol 20 (3) ◽  
pp. 760-768 ◽  
Author(s):  
R. G. Newton ◽  
J. R. Scott

Abstract A study has been made of the influence of the following factors on the relative rates of tensile deterioration of natural rubber vulcanizates in the Geer oven and oxygen bomb, both at 70° C : period of vulcanization, sulfur ratio, nature of accelerator. Expressing this relation as the oven/bomb ratio, i.e., the ratio between oven and bomb aging periods that give the same deterioration, the following conclusions are drawn. (1) Varying the period of vulcanization of a given mix over a moderate range (2:3) around the optimum does not noticeably alter the oven/bomb ratio, except in unaccelerated mixes, where overvulcanization gave an abnormally low ratio, owing to the rubber perishing very rapidly in the oven. (2) The effect of varying the sulfur ratio within the usual limits for soft rubbers is small, and appears to result from the quicker vulcanization of the mixes richer in sulfur. (3) The nature of the accelerator profoundly affects the ratio, values ranging from 3 to 27 being found among the present mixes ; this effect is believed to be exerted through the influence of the accelerator both on rate of vulcanization and on the oxidizability of the vulcanizate. Theoretical considerations indicate that a rubber which vulcanizes quickly and (or) oxidizes slowly should give a low oven/bomb ratio, whereas one that vulcanizes slowly and(or) oxidizes quickly should give a higher ratio. The experimental data are generally in accord with this, and there is evidence that both rate of vulcanization and oxidizability can have an important effect, but the data do not enable the separate effect of each to be assessed exactly. The bearing of the results on the use of the oven and bomb tests is briefly discussed. It is shown that they demonstrate the fallacy of using a single factor for converting oven to bomb aging periods or vice versa, and that the relative natural aging resistances of widely different vulcanizates cannot be reliably assessed by either test, a limitation arising from the fact that the relative importance of oxidative decay and aftervulcanization varies from one type of mix to another, and that the temperature coefficients of these processes are not necessarily the same. These facts are very important in relation to the choice and application of accelerated aging tests for specification purposes, since these usually have to be applied to rubbers of unknown compositions, which are likely to vary widely in their relative response to different aging conditions.


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