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Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Xue Li ◽  
Peng Lou ◽  
Longquan Yang

[email protected] microspheres with different phenolic (RF) layer thicknesses are prepared by adjusting the polymerization time. With the prepared [email protected] as the precursor, [email protected] composite microspheres with rattle-like morphology are obtained through one-step controlled carbonization. This method simplifies the preparation of rattle-shaped microspheres from sandwich microspheres. [email protected] microspheres exhibit excellent microwave absorbing properties. The morphology and composition of the product are investigated depending on the effects of carbonization temperature, time and thickness of the RF layer. When the carbonization temperature is 700 °C, the carbonization time is 12 h and the polymer shell thickness is 62 nm, the inner hollow Fe3O4 is completely reduced to Fe. The absorption properties of the materials are compared before and after the reduction of Fe3O4. Both [email protected] and [email protected] show excellent absorbing properties. When the filler content is 50%, the maximum reflection loss (RLmax) of the rattle-shaped [email protected] microspheres is −50.15 dB, and the corresponding matching thickness is 3.5 mm. At a thickness of 1.7 mm, the RLmax of [email protected] is −44.42 dB, which is slightly worse than that of [email protected] Both dielectric loss and magnetic loss play a vital role in electromagnetic wave absorption. This work prepares rattle-shaped absorbing materials in a simple way, which has significance for guiding the construction of rattle-shaped materials.


MAUSAM ◽  
2021 ◽  
Vol 44 (1) ◽  
pp. 35-38
Author(s):  
BHUKAN LAL

Seasonal and annual surface air temperature of Delhi has been analysed for 90-year period (1901-1990) for finding trends and periodicities. The analysis revealed that frequency distribution of all the four seasons as well as of annual time series is normal. Markov linear-type of persistence is observed in pre and post-monsoon seasons. Recent period {1961-1990) averages of temperature are significantly lower than the long period means in respect of annual, monsoon and pre-monsoon seasons. Decreasing trend is noticed in monsoon and annual temperature time series. Low-pass filter analysis suggests that the trend is not linear but oscillatory consisting periods of 10 years or more.


Author(s):  
Hesham Salem ◽  
Amany Abdelaziz ◽  
Aliaa Gamal ◽  
Ramy El Sabaa

A dependable, sensitive, basic and cheap spectrofluorimetric approach has been created for test of sulfur-containing drug; ixabepilone in bulk powder, vials and human plasma. The approach depends on the quenching effect of ixabepilone on the fluorescence intensity of acetoxymercuric fluorescene (AMF) reagent at λem of 530 nm and λex of 500 nm. Parameters which will control the reaction such as pH, AMF solution concentration, temperature, time and solvents were examined and optimized. According to the optimized conditions, the proposed approach was practiced over the concentration area of 20-100 ng mL-1 with adequate linearity (r = 0.9998). The developed approach was approved confirming to ICH rules in terms of accuracy, precision, linearity, LOD and LOQ. The proposed approach was practiced to analyze ixabepilone in Ixempra® vials with satisfactory recovery % of 99.89 and RSE% of 1.24. The results achieved were compared to those achieved by an already reported HPLC approach.


2021 ◽  
Author(s):  
Christopher Kadow ◽  
David M. Hall ◽  
Uwe Ulbrich ◽  
Johannes Meuer ◽  
Thomas Ludwig

<p>Historical temperature measurements are the basis of global climate datasets like HadCRUT4. This dataset contains many missing values, particularly for periods before the mid-twentieth century, although recent years are also incomplete. Here we demonstrate that artificial intelligence can skilfully fill these observational gaps when combined with numerical climate model data. We show that recently developed image inpainting techniques perform accurate monthly reconstructions via transfer learning using either 20CR (Twentieth-Century Reanalysis) or the CMIP5 (Coupled Model Intercomparison Project Phase 5) experiments. The resulting global annual mean temperature time series exhibit high Pearson correlation coefficients (≥0.9941) and low root mean squared errors (≤0.0547 °C) as compared with the original data. These techniques also provide advantages relative to state-of-the-art kriging interpolation and principal component analysis-based infilling. When applied to HadCRUT4, our method restores a missing spatial pattern of the documented El Niño from July 1877. With respect to the global mean temperature time series, a HadCRUT4 reconstruction by our method points to a cooler nineteenth century, a less apparent hiatus in the twenty-first century, an even warmer 2016 being the warmest year on record and a stronger global trend between 1850 and 2018 relative to previous estimates. We propose image inpainting as an approach to reconstruct missing climate information and thereby reduce uncertainties and biases in climate records.</p> <p>As published in:</p> <p>Kadow, C., Hall, D.M. & Ulbrich, U. Artificial intelligence reconstructs missing climate information. <em>Nat. Geosci.</em> <strong>13, </strong>408–413 (2020). https://doi.org/10.1038/s41561-020-0582-5</p> <p>Newest developments around the technology will be presented.</p> <p> </p>


2021 ◽  
Author(s):  
Igor A. Botygin ◽  
Valery Tartakovsky ◽  
Vladislav Sherstnev ◽  
Anna Sherstneva ◽  
Nikita Shkulov

Author(s):  
І. Doschechkina

The aim of the work is to develop a method of increasing the technological plasticity while maintaining the strength and preventing aging of blanks of cold-rolled sheet steel 08Yu. The task of this work is research and determination of optimal temperature-time parameters of high-speed contact recrystallization annealing and subsequent aging of 08Yu steel sheet blanks to obtain the required level of mechanical properties that would improve their deformability and ability of very deep drawing during cold stamping of products. The optimal parameters of the speed mode are set recrystallization annealing of cold-rolled 08Yu sheet steel, which provides the best structure and properties for further cold pressure treatment. The temperature-time modes of further aging and possibilities to prevent the processes of its natural aging during prolonged operation or transportation have been studied. The method and modes of heat treatment of blanks from finished 08Yu sheet steel to facilitate their deformability and improve stamping in order to reduce waste in the manufacture of products by cold deformatiion with deep and complex drawing were suggested.


2021 ◽  
Vol 11 (2) ◽  
pp. 48-55
Author(s):  
Nikolay M. BOCHAROV

The study of the nature of high-temperature corrosion of metals is one of the tasks in substantiating the relevance of the use of corrosion-resistant, heat-resistant coatings and barrier layers obtained on the basis of the natural oxidation process. The article presents the gradation of oxidation of surfaces of 08kp thin-sheet steel at diff erent temperature-time parameters of one cycle “heating-cooling”. To regulate the processing modes and register thermal eff ects, a diff erential thermal analysis device was used. It is shown that the eff ect of elevated temperatures on steel in air at atmospheric pressure triggers an intensive growth of scale, which peels off from the metal base and breaks down. After descaling on the steel surface, in addition to blue tarnishing, in some cases, fi lms of a red tint were found. Based on the data of diff erential thermal analysis, an att empt was made to separate and interpret transformations related directly to steel and to reactions in scale associated with iron oxides.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7591
Author(s):  
Pedro M. A. Pereira ◽  
Joana R. Bernardo ◽  
Luisa Bivar Roseiro ◽  
Francisco Gírio ◽  
Rafał M. Łukasik

Biomass pre-treatment is a key step in achieving the economic competitiveness of biomass conversion. In the present work, an imidazole pre-treatment process was performed and evaluated using wheat straw and eucalyptus residues as model feedstocks for agriculture and forest-origin biomasses, respectively. Results showed that imidazole is an efficient pre-treatment agent; however, better results were obtained for wheat straw due to the recalcitrant behavior of eucalyptus residues. The temperature had a stronger effect than time on wheat straw pre-treatment but at 160 °C and 4 h, similar results were obtained for cellulose and hemicellulose content from both biomasses (ca. 54% and 24%, respectively). Lignin content in the pre-treated solid was higher for eucalyptus residues (16% vs. 4%), as expected. Enzymatic hydrolysis, applied to both biomasses after different pre-treatments, revealed that results improved with increasing temperature/time for wheat straw. However, these conditions had no influence on the results for eucalyptus residues, with very low glucan to glucose enzymatic hydrolysis yield (93% for wheat straw vs. 40% for eucalyptus residues). Imidazole can therefore be considered as a suitable solvent for herbaceous biomass pre-treatment.


Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7677
Author(s):  
Lavinia Berta ◽  
Năstaca-Alina Coman ◽  
Aura Rusu ◽  
Corneliu Tanase

The study of bimetallic nanoparticles (BNPs) has constantly been expanding, especially in the last decade. The biosynthesis of BNPs mediated by natural extracts is simple, low-cost, and safe for the environment. Plant extracts contain phenolic compounds that act as reducing agents (flavonoids, terpenoids, tannins, and alkaloids) and stabilising ligands moieties (carbonyl, carboxyl, and amine groups), useful in the green synthesis of nanoparticles (NPs), and are free of toxic by-products. Noble bimetallic NPs (containing silver, gold, platinum, and palladium) have potential for biomedical applications due to their safety, stability in the biological environment, and low toxicity. They substantially impact human health (applications in medicine and pharmacy) due to the proven biological effects (catalytic, antioxidant, antibacterial, antidiabetic, antitumor, hepatoprotective, and regenerative activity). To the best of our knowledge, there are no review papers in the literature on the synthesis and characterisation of plant-mediated BNPs and their pharmacological potential. Thus, an effort has been made to provide a clear perspective on the synthesis of BNPs and the antioxidant, antibacterial, anticancer, antidiabetic, and size/shape-dependent applications of BNPs. Furthermore, we discussed the factors that influence BNPs biosyntheses such as pH, temperature, time, metal ion concentration, and plant extract.


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