scholarly journals Morphology and Chemical Purity of Water Suspension of Graphene Oxide FLAKES Aged for 14 Months in Ambient Conditions. A Preliminary Study

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4108
Author(s):  
Adrian Chlanda ◽  
Krystian Kowiorski ◽  
Marcin Małek ◽  
Ewa Kijeńska-Gawrońska ◽  
Monika Bil ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Chemical Properties ◽  
Ambient Conditions ◽  
Long Term Storage ◽  
Graphene Derivatives ◽  
Nanoscale Characterization ◽  
Chemical Purity ◽  
Preliminary Study ◽  
Term Storage

Graphene and its derivatives have attracted scientists’ interest due to their exceptional properties, making them alluring candidates for multiple applications. However, still little is known about the properties of as-obtained graphene derivatives during long-term storage. The aim of this study was to check whether or not 14 months of storage time impacts graphene oxide flakes’ suspension purity. Complementary micro and nanoscale characterization techniques (SEM, AFM, EDS, FTIR, Raman spectroscopy, and elemental combustion analysis) were implemented for a detailed description of the topography and chemical properties of graphene oxide flakes. The final step was pH evaluation of as-obtained and aged samples. Our findings show that purified flakes sustained their purity over 14 months of storage.

Technology and organization of storage of combine harvesters

2021 ◽  
pp. 9-17
Author(s):  
N. M. Morozova
Keyword(s):  
Chemical Properties ◽  
Long Term Storage ◽  
Scientific Task ◽  
Atmospheric Factors ◽  
Combine Harvesters ◽  
Physical And Chemical ◽  
Technical And Organizational Measures ◽  
Term Storage ◽  
And Chemical Properties

During long-term storage, climatic and atmospheric factors affect the agricultural machine, which cause changes in the physical and chemical properties of structural materials, technical fluids, lubricants. Therefore, the development of technical and organizational measures related to improving the storage efficiency of combine harvesters is an urgent scientific task that the leading scientific institutes of the country are engaged in.

Modern methods to reduce evaporation and ensure safety when storing petroleum products in tanks

2021 ◽  
Vol 94 ◽  
pp. 65-75
Author(s):  
A. M. Kuzminskaya ◽  
◽  
M. V. Buzaeva ◽  
O. V. Ageeva ◽  
◽  
...  
Keyword(s):  
Negative Impact ◽  
Fire Hazard ◽  
Chemical Properties ◽  
Petroleum Products ◽  
Oil Refining ◽  
Chemical Additives ◽  
Long Term Storage ◽  
Main Components ◽  
Term Storage

Introduction. With long-term storage of gasoline in large-capacity tanks, the problem associated with their volatility becomes urgent. Evaporation of petroleum products and gasoline leads to a change in their physical and chemical properties, a decrease in the yield of light petroleum products during oil refining, and a deterioration in the performance characteristics of engines. In this regard, it becomes difficult to start engines, their reliability, fuel consumption increases and the service life is reduced. Lost light hydrocarbons pollute the environment and increase the fire hazard of enterprises. The aim of the work is to identify effective, inexpensive and safe methods for reducing the volatility of oil products, including gasoline, when stored in tanks. Research methods. A retrospective analysis of studies on the problems of reducing losses of petroleum products during their storage, transportation and use is carried out. Technical and organizational methods for reducing the evaporation of fuels and the use of chemical additives as an inexpensive and effective method for solving the problem of the volatility of gasolines are considered. The conclusion about the efficiency of using chemical additives to fuels to reduce volatility has been substantiated. Results and their discussion. Conclusions are made about the possibility of using surfactants as additives to reduce the evaporation of gasolines during long-term storage in tanks. The analysis of the main components and methods for the synthesis of surfactant compositions capable of creating a surfactant film at the liquid-atmosphere interface, which protects the liquid from evaporation. Conclusion. Reducing the volatility of gasoline with the use of inexpensive and effective additives introduced into the fuel in small quantities, not only reduces the explosion and fire hazard during storage in large tanks, reduces losses, but also prevents the negative impact on the environment from the ingress of low molecular hydrocarbons into it. Key words: volatility of petroleum products, losses during storage of gasoline, methods of reducing volatility, additives.

scholarly journals Synthesis of Caffeoyl-Prolyl-Histidyl-Xaa Derivatives and Evaluation of Their Activities and Stability upon Long-Term Storage

2021 ◽  
Vol 22 (12) ◽  
pp. 6301
Author(s):  
Hyeri Jeong ◽  
Young-Eun Jeon ◽  
Jin-Kyoung Yang ◽  
Jaehi Kim ◽  
Woo-Jae Chung ◽  
...  
Keyword(s):  
Large Scale ◽  
Antioxidative Activity ◽  
Solid Phase ◽  
Critical Role ◽  
Radical Scavenging ◽  
Scale Production ◽  
Ambient Conditions ◽  
Long Term Storage ◽  
Term Storage

Antioxidants play a critical role in the treatment of degenerative diseases and delaying the aging of dermal tissue. Caffeic acid (CA) is a representative example of the antioxidants found in plants. However, CA is unsuitable for long-term storage because of its poor stability under ambient conditions. Caffeoyl-Pro-His-NH2 (CA-Pro-His-NH2, CA-PH) exhibits the highest antioxidant activity, free radical scavenging and lipid peroxidation inhibition activity among the histidine-containing CA-conjugated dipeptides reported to date. The addition of short peptides to CA, such as Pro-His, is assumed to synergistically enhance its antioxidative activity. In this study, several caffeoyl-prolyl-histidyl-Xaa-NH2 derivatives were synthesized and their antioxidative activities evaluated. CA-Pro-His-Asn-NH2 showed enhanced antioxidative activity and higher structural stability than CA-PH, even after long-term storage. CA-Pro-His-Asn-NH2 was stable for 3 months, its stability being evaluated by observing the changes in its NMR spectra. Moreover, the solid-phase synthetic strategy used to prepare these CA-Pro-His-Xaa-NH2 derivatives was optimized for large-scale production. We envision that CA-Pro-His-Xaa-NH2 derivatives can be used as potent dermal therapeutic agents and useful cosmetic ingredients.

scholarly journals Probing Phonons in Plutonium

2003 ◽  
Vol 802 ◽  
Author(s):  
Joe Wong ◽  
Michael Krisch ◽  
Daniel L. Farber ◽  
Florent Occelli ◽  
Adam J. Schwartz ◽  
...  
Keyword(s):  
Solid State ◽  
Chemical Properties ◽  
Pure Metal ◽  
Detailed Understanding ◽  
Safety Issues ◽  
Long Term Storage ◽  
Toxic Materials ◽  
Physico Chemical ◽  
Term Storage

Plutonium (Pu) is well known to have complex and unique physico-chemical properties [1]. Notably, the pure metal exhibits six solid-state phase transformations with large volume expansions and contractions along the way to the liquid state: α → β → γ → δ → δ' → ε→ liquid. Unalloyed Pu melts at a relatively low temperature ∼640 °C to yield a higher density liquid than that of the solid from which it melts, (Figure 1). Detailed understanding of the properties of plutonium and plutonium-based alloys is critical for the safe handling, utilization, and long-term storage of these important, but highly toxic materials. However, both technical and and safety issues have made experimental observations extremely difficult.

scholarly journals Degradation of selected nutrients in sunflower oils during long-term storage

2014 ◽  
Vol 32 (No. 6) ◽  
pp. 595-600 ◽  
Author(s):  
L. Vrbiková ◽  
Š. Schmidt ◽  
F. Kreps ◽  
L. Tmáková ◽  
M. Čertík ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Oxidative Stability ◽  
Chemical Properties ◽  
Beta Carotene ◽  
Storage Conditions ◽  
Pet Bottles ◽  
Long Term Storage ◽  
Sunflower Oils ◽  
Term Storage

We investigated the influence of long-term storage (10 months) at an average ambient temperature of 25°C on oxidative stability of sunflower oils (made in Slovakia, Czech Republic, Austria, and Hungary) and their nutrients. Chemical properties were determined and changes in oxidative stability monitored. Oil samples were collected and analysed for the content of tocopherols and β-carotene. Degradation of nutrients depends on chemical composition of oils and storage conditions. It was found that the concentration of both antioxidants decreased in all the samples with the increase in storage time. According to the results, losses of total tocopherols and β-carotene in refined sunflower oils stored in transparent 5-l PET bottles and exposed to daylight at ambient temperature were found to be 52–64% and 63–65%, respectively. The country of origin had no statistically significant impact on the oxidative stability of stored sunflower oils.  

Using graphene oxide to reactivate the anaerobic ammonium oxidizers after long-term storage

2014 ◽  
Vol 2 (2) ◽  
pp. 974-980 ◽  
Author(s):  
Gang Wang ◽  
Xiaochen Xu ◽  
Fenglin Yang ◽  
Hanmin Zhang ◽  
Dong Wang
Keyword(s):  
Graphene Oxide ◽  
Long Term Storage ◽  
Term Storage

Preservation of nutrients during long-term storage of source-separated yellowwater

2012 ◽  
Vol 66 (4) ◽  
pp. 804-809 ◽  
Author(s):  
Adam M. Paruch
Keyword(s):  
Chemical Properties ◽  
Oxygen Demand ◽  
Storage Period ◽  
Wastewater Management ◽  
Long Term Storage ◽  
Temperature Regimes ◽  
Ph Level ◽  
Term Storage

Source separation of human urine (yellowwater) enhances the sustainability of wastewater management and efficiency of nutrient recovery and recycling. Storage of source-separated yellowwater is recommended prior to agronomic reuse. At this point, it is of immense interest to determine the effect of storage time on quality of yellowwater. Therefore, this study focused on examining changes in some chemical properties of raw, undiluted, freshly collected, source-separated yellowwater stored for a period of 1 year under different temperature regimes: cold (4 °C), mild (10 °C) and warm (22 °C). Chemical parameters (biochemical oxygen demand (BOD5), N-tot, N-NO2, N-NO3, N-NH4, P-tot, K, S, and pH), with the main focus on fertiliser nutrient compounds intended for agricultural utilisation, were tested. The outcomes revealed that both nitrification and denitrification processes took place in the stored yellowwater, and an increase in the pH level of up to pH greater than 9 was observed. The study found that the main macronutrients can be well preserved in yellowwater, as there were no substantial changes in the contents of these elements over a 1 year storage period at the three temperatures tested.

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