Analytical Investigation on the Aging Process of Vegetable Insulating Oil

2013 ◽  
Vol 683 ◽  
pp. 608-611
Author(s):  
Ning Zhang ◽  
Ying Hui Han ◽  
Xue Yang ◽  
Shuo Zhang ◽  
Song Wei

Development and improvement of environment-friendly insulating oil is one of the hot topics in electric industry and academic field. Vegetable insulating oil (VIO) has the higher ignition temperature and higher flash point .The biodegradation rate of VIO is also higher, while its electrical properties are equal to mineral insulating oil. A lot of technologies, including the addition antioxidants, hydrogenation, microwave, and other related technologies, can enhance the aging resistance and improve the practicability of the VIO. In this paper, the aging mechanism of VIO was analyzed and the related modified measures were summarized, which lays the foundation for further studies.

2012 ◽  
Vol 562-564 ◽  
pp. 380-384
Author(s):  
Bian Hua Li ◽  
Qi Cheng Liu ◽  
Yan Juan Yu ◽  
Du Ming Gong

The durability of the asphalt is of great significance to its pavement performance, so more and more effort has been addressed on improving the asphalt anti-aging performance. In this work, the effects of antioxidant type and formula on the asphalt anti-aging performance were investigated through various measurements before and after aging process including needle penetration, softening point and ductility. Furthermore, the aging mechanism was analyzed via the FTIR (Fourier Transform Infrared) test. As a result, composite antioxidant can observably improve aging resistance of the asphalt. When the formula is 1.2%B+1.5%C+1.2%D, the needle penetration, ductility, softening point are as follows: 39.4×10-1mm, 148.1cm, 52.1°C. FTIR shows that carbonyl absorption peak reduced. Moreover, composite antioxidant can be more stable improvement of asphalt aging effect due to the cooperativity.


Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1243
Author(s):  
Fan Zhang ◽  
Yufei Cao ◽  
Xuan Liu ◽  
Huan Xu ◽  
Diannan Lu ◽  
...  

Understanding the aging mechanism of polypropylene (PP) is fundamental for the fabrication and application of PP-based materials. In this paper, we present our study in which we first used reactive molecular dynamics (RMD) simulations to explore the thermo-oxidative aging of PP in the presence of acetic acid or acetone. We studied the effects of temperature and oxygen on the aging process and discussed the formation pathways of typical small molecule products (H2, CO, CO2, CH4, C2H4, and C2H6). The effect of two infection agents, acetic acid and acetone, on the aging reaction was analyzed emphatically. The simulation results showed that acetone has a weak impact on accelerating the aging process, while acetic acid has a significant effect, consistent with previous experimental studies. By tracking the simulation trajectories, both acetic acid and acetone produced small active free radicals to further react with other fragment products, thus accelerating the aging process. The first reaction step of acetic acid is often the shedding of the H atom on the hydroxyl group, while the reaction of acetone is often the shedding of the H atom or the methyl. The latter requires higher energy at lower temperatures. This is why the acceleration effect of acetone for the thermo-oxidative aging of PP was not so significant compared to acetic acid in the experimental temperature (383.15 K).


2007 ◽  
Vol 124-126 ◽  
pp. 1481-1484 ◽  
Author(s):  
Jin Kyu Lee ◽  
Young Ok Yoon ◽  
Shae K. Kim

Molten Mg alloys burn rapidly in air if not protected. In order to handle molten Mg safely, the molten metal should be protected from oxidation by covering the surface with flux or protective gases. Sulfur hexafluoride (SF6) gas is widely used for Mg alloy as a cover gas and has proved to be a successful inhibitor. However, the use of SF6 gas is limited because of its high cost and its significant impact on global warming potential (GWP). Therefore, SF6 gas is being replaced by alternative protection gases such as tetrafluoro ethane (HFC-134a) and 3M NovecTM 612. These gases are less expensive and have lower GWP, compared with SF6 gas. Recent studies show that there has been another attempt by adding CaO into Mg alloys to manufacture CaO added AZ31Mg alloy in terms of increasing ignition temperature and reducing protective cover gas amount during melting and casting. This paper discusses effect of CaO on ignition and oxidation behaviors of AZ31 Mg alloy as well as on surface roughness and mechanical properties of AZ31 Mg alloy extruded bars.


2014 ◽  
Vol 599 ◽  
pp. 265-270 ◽  
Author(s):  
Pan Fei Liu ◽  
Jun Zheng ◽  
Shao Peng Wu

In this paper the effect of Layered double hydroxides (LDHs) on aging properties of asphalts was studied. The thin film oven test TFOT tests and ultraviolet (UV) aging process were used to simulate short-term and long-term aging of asphalts, respectively. After aging, the physical properties and dynamic shear rheological behaviors of LDHs modified asphalts were investigated. The viscosity of LDHs modified asphalts was measured by Brookfield viscometer before and after UV aging. After UV aging, with an increase of LDHs, softening point and viscosity value of modified asphalts decreased, while both of ductility and penetration increased, compared to base asphalts. Temperature sweep tests showed that the complex modulus of LDHs modified asphalts was lower than that of base asphalt, while phase angle was higher. The results showed that LDHs improved the UV aging resistance of the asphalt, and it could prevent asphalt from UV aging.


2021 ◽  
Vol 9 (2) ◽  
pp. 150
Author(s):  
Shannaz Nadia Yusharyahya

Seiring dengan meningkatnya populasi geriatri di Indonesia, masalah penuaan kulit juga turut meningkat. Pada populasi tersebut terjadi berbagai perubahan kulit sehingga kelainan yang ditimbulkan juga berbeda. Stres oksidatif merupakan mekanisme yang diduga kuat sebagai penyebab utama penuaan kulit. Penuaan kulit merupakan proses kompleks yang melibatkan faktor intrinsik dan ekstrinsik. Faktor intrinsik yang berperan adalah genetik, metabolisme sel, dan perubahan hormonal. Selain itu, terdapat faktor ekstrinsik seperti radiasi ultraviolet, inframerah, dan karsinogen lingkungan yang turut berperan pada penuaan kulit. Kedua faktor tersebut menyebabkan perubahan di seluruh lapisan kulit. Untuk mengatasi penuaan kulit, kini telah tersedia berbagai modalitas terapi, namun untuk menentukan terapi yang paling sesuai perlu diketahui fisiologi kulit menua, mekanisme penuaan kulit, dan manifestasi kelainan klinis kulit menua. Secara fisiologi terjadi perubahan permeabilitas, biokimia, vaskularisasi, termoregulasi, respons terhadap iritan, respons imunitas, kapasitas regenerasi, respons terhadap cedera, persepsi neurosensori dan pada tingkat genom. Jumlah sel epidermal dan laju pergantian epidermal menurun sedangkan di adneksa terjadi penurunan jumlah kelenjar sebasea yang mengakibatkan kulit kering dan mudah pecah. Penurunan jumlah melanosit menyebabkan warna rambut menjadi abu-abu keputihan dan muncul pigmentasi atipik di kulit. Folikel rambut kurang aktif sehingga meningkatkan kerontokan dan kebotakan. Di lapisan basal ukuran sel berkurang dan rerata ukuran sel bertambah. Sel keratinosit menjadi lebih pendek dan besar di kulit yang menua. Kata kunci: geriatri, mekanisme penuaan kulit, patofisiologi.   Skin Aging Mechanism as A Basic Prevention and Treatment of Skin Aging Abstract Growing geriatric population generates a rise of aging issues. Process of aging develops multiple skin changes that further emerge other related skin problems. Oxidative stress is believed playing vital role related to aging. The aging process in the skin is complex and influenced by intrinsic and extrinsic factors. Intrinsic factors can be in the form of genetics, cell metabolism, and hormonal changes. Meanwhile, for extrinsic factors, such as exposure to ultraviolet, infrared, and carcinogenic agent also have crucial part in aging process. These factors contribute to all layers of the skin. Nowadays, many treatment modalities available to reverse skin aging, however, better understanding on skin aging mechanism, the pathophysiology, and clinical manifestations of aging skin is important to choose the appropriate treatment for patients. In aging, there are physiological changes in permeability, biochemical structures, vascularisation, thermoregulation, irritative response, immunity response, regenerative capability, inflammatory response, neurosensory perception and in genom level. The number of epidermal cells and epidermal overturn rate decline while there is also reduction of sebaseous glands at adnexa which both are accounted for skin xerosis. Decreasing melanocytes can caused gray hair and atypical pigmentation. Hair follicles also show less activity resulting in hair loss. Basal layer cells are downsizing and rise of average cells size are occured. Keratinocyte becomes shorter and bigger in aging skin. Keywords: geriatric, mechanism, skin aging, pathophysiology.


2021 ◽  
Vol 902 ◽  
pp. 59-63
Author(s):  
Kanin Wajanasoonthon ◽  
Amnart Suksri

Generally, power transformers have been using mineral oil as a liquid insulator due to its availability and excellent dielectric property. However, petroleum sources are depleting, which implies that mineral oil is going to be limited in availability. So, this research is to investigate on vegetable oil with nanographene filler as a substitution. Vegetable insulating oil is considered as environment-friendly insulating oil due to their superiority of biodegradable, nature-friendly, high fire-point, and good level of breakdown voltage (BV). Nevertheless, vegetable insulating oil have high viscosity, leading to a slow flow rate on the cooling performance of power transformers. To solve this problem, a process of transesterification was used to produce palm oil methyl ester (POME) from a refined bleached deodorized palm olein (RBDPO) to reduce its viscosity. RBDPO and POME were used as two kinds of fluid-based to combine with graphene nanoparticles (GNPs). Electrical breakdown voltage tests were performed by the IEC60156 standard. The results shown that POME have higher BV than RBDPO but adding GNPs may lead to lower BV even with a small amount of concentration. Nevertheless, every nanofluid has a higher BV than 30 kV.


2016 ◽  
Vol 847 ◽  
pp. 413-417 ◽  
Author(s):  
Li Gao ◽  
Jian Ying Yu ◽  
Min Wu ◽  
Li Hui Xue

Ultraviolet (UV) absorber residue was used to modify bitumen. Effects of UV absorber residue on thermo-oxidative and UV aging properties of bitumen were evaluated by conventional physical properties and SARA (saturates, aromatics, resins and bitumenenes) analysis. The results showed that the viscosity aging index (VAI) and softening point increment (SPI) of bitumen decreased significantly due to introduction of the UV absorber residue, and the ductility retention rate (DRR) was evidently higher compared to the pristine bitumen. SARA show that UV absorber residue can effectively restrain the gelatinization of bitumen resulted from aging. As a consequence, the UV absorber residue modified bitumen displays enhanced aging resistance properties, which can be attributed to the physical sorption of activated carbon to lighter components in the thermo-oxidative aging process and the absorption of UV absorption residue to the ultraviolet light in the process of UV aging.


Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 345
Author(s):  
Hsiao-Yu Huang ◽  
Hao-I Chen ◽  
Yuh-Jeen Huang

The promoter ZrO2 was applied to prevent Cu crystallites from sintering over CZ (ca. Cu 30 wt.% and Zn 70 wt.%) under partial oxidation of the methanol (POM) reaction. Gold was selected to promote the performance of CZrZ (ca. Cu 31 wt.%, Zr 16 wt.%, and Zn 53 wt.%) catalyst to overcome a high ignition temperature of 175 °C and CO selectivity (SCO) (>10% at T. > 200 °C). Experimentally, the deactivation rate constant of A5CZrZ (ca. Au 5 wt.%, Cu 31 wt.%, Zr 17 wt.%, and Zn 47 wt.%) and CZrZ was 1.7 times better than A5CZ (ca. Au 5 wt.%, Cu 31 wt.%, and Zn 64 wt.%) and CZ. The methanol conversion of CZrZ and A5CZrZ catalysts was kept higher than 70% for 12 h in an accelerated aging process. Meanwhile, the Au prompted more methoxy species oxidizing to formate on Cu+-rich A5CZrZ surface at lower temperature, and also improved CO transfer from formate reacting with moveable oxygen to form CO2. The SCO can lower to ca. 6% at 200 °C after adding 3–5% of gold promoter. These features all prove that the CZ catalyst with ZrO2 and Au promoters could enhance catalytic activity, lower the SCO and ignition temperature, and maintain good durability in the POM reaction.


2021 ◽  
Vol 1035 ◽  
pp. 944-950
Author(s):  
Zhao Yang Liu ◽  
San Peng Mao ◽  
Gui Tao Zheng ◽  
Zhi Long Cao ◽  
Lian Li ◽  
...  

Based on the reason that SBS modified bitumen (SMB) with sulfur stabilizer is easy to degrade during aging, a novel non-sulfur stabilizer, P-benzoquinone oxime (GMF), was used to modify SMB. The effects of GMF and sulfur stabilizer on the thermal storage stability, low-temperature performance and aging resistance of SMB were investigated. The results indicate that GMF is more beneficial to improve the thermal storage stability, the low temperature flexibility and softening point of SMB than that of sulfur. And GMF can restrain the degradation of the low temperature flexibility of SMB after thermal aging as compared with sulfur. Fourier transform infrared spectroscopy indicates that the aging growth index of GMF/SBS modified bitumen is 33.5% lower than that of sulfur/SBS modified bitumen after aging. Fluorescence microscope proves that the addition of GMF can prevent the destruction of cross-linking network structure of SBS in bitumen during aging process, which also demonstrates that GMF can improve the aging resistance of SMB. Therefore, GMF can be more suitable as a stabilizer for SMB.


Sign in / Sign up

Export Citation Format

Share Document