base substrate
Recently Published Documents


TOTAL DOCUMENTS

66
(FIVE YEARS 21)

H-INDEX

9
(FIVE YEARS 2)

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Li-Ping Xu ◽  
Shaoqun Qian ◽  
Zhe Zhuang ◽  
Jin-Quan Yu ◽  
Djamaladdin G. Musaev

AbstractThe search for more effective and highly selective C–H bond oxidation of accessible hydrocarbons and biomolecules is a greatly attractive research mission. The elucidating of mechanism and controlling factors will, undoubtedly, help to broaden scope of these synthetic protocols, and enable discovery of more efficient, environmentally benign, and highly practical new C–H oxidation reactions. Here, we reveal the stepwise intramolecular SN2 nucleophilic substitution mechanism with the rate-limiting C–O bond formation step for the Pd(II)-catalyzed C(sp3)–H lactonization in aromatic 2,6-dimethylbenzoic acid. We show that for this reaction, the direct C–O reductive elimination from both Pd(II) and Pd(IV) (oxidized by O2 oxidant) intermediates is unfavorable. Critical factors controlling the outcome of this reaction are the presence of the η3-(π-benzylic)–Pd and K+–O(carboxylic) interactions. The controlling factors of the benzylic vs ortho site-selectivity of this reaction are the: (a) difference in the strains of the generated lactone rings; (b) difference in the strengths of the η3-(π-benzylic)–Pd and η2-(π-phenyl)–Pd interactions, and (c) more pronounced electrostatic interaction between the nucleophilic oxygen and K+ cation in the ortho-C–H activation transition state. The presented data indicate the utmost importance of base, substrate, and ligand in the selective C(sp3)–H bond lactonization in the presence of C(sp2)–H.


2021 ◽  
Author(s):  
Frank Dehn ◽  
Engin Kotan

Abstract Background: To evaluate the usability of mycelium-based materials for construction, first tests were carried out to determine their suitability for thermal insulation. Different substrate compositions were tested for various physical properties. The compositions and experimental setups used are described in the “Methods” section. Results: Materials based on fungal mycelium were found to have promising properties for use in the construction sector. Their thermal conductivities are comparable to those of commercially available ecological insulation materials. As material properties turned out to be dependent on the substrate used for the production of mycelium materials, further optimisation is required. Conclusion: For first preliminary tests [1] to study the performance of mycelium-based materials, different additives (beech wood, rice husks, coffee silver skin, perlite rock) were added to a base substrate to determine their influence on physical properties. Compared to the characteristics of conventional thermal insulation materials, the test results obtained are rather promising and confirm suitability of mycelium-based materials for building. However, further systematic studies are needed to investigate options to improve major properties and to ensure reproducibility of mycelium materials with largely homogeneous properties.


Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1634
Author(s):  
Sarthak Acharya ◽  
Shailesh Singh Chouhan ◽  
Jerker Delsing

Advancements in production techniques in PCB manufacturing industries are still required as compared to silicon-ICs fabrications. One of the concerned areas in PCBs fabrication is the use of conventional methodologies for metallization. Most of the manufacturers are still using the traditional Copper (Cu) laminates on the base substrate and patterning the structures using lithography processes. As a result, significant amounts of metallic parts are etched away during any mass production process, causing unnecessary disposables leading to pollution. In this work, a new approach for Cu metallization is demonstrated with considerable step-reducing pattern-transfer mechanism. In the fabrication steps, a seed layer of covalent bonded metallization (CBM) chemistry on top of a dielectric epoxy resin is polymerized using actinic radiation intensity of a 375 nm UV laser source. The proposed method is capable of patterning any desirable geometries using the above-mentioned surface modification followed by metallization. To metallize the patterns, a proprietary electroless bath has been used. The metallic layer grows only on the selective polymer-activated locations and thus is called selective metallization. The highlight of this production technique is its occurrence at a low temperature (20–45 °C). In this paper, FR-4 as a base substrate and polyurethane (PU) as epoxy resin were used to achieve various geometries, useful in electronics packaging. In addition, analysis of the process parameters and some challenges witnessed during the process development are also outlined. As a use case, a planar inductor is fabricated to demonstrate the application of the proposed technique.


2021 ◽  
Author(s):  
Vithoria Réggia Gomes Pessanha ◽  
Maria das Graças Machado Freire ◽  
Michel Picanço Oliveira ◽  
Bárbara Ferreira de Oliveira

Mycocomposites have received special attention from both academic and commercial environments. These materials give a new purpose to agricultural residues, bringing benefits to companies, society and the environment. Currently, they have been studied to replace synthetic materials such as polyester. However, its field of application is still very limited, making it necessary for more research to be carried out. In this work, mycocomposites were produced in two configurations: without jute and with two jute arranged at 1/3 of the thickness in relation to the surfaces perpendicular to loading plains during bending and compression tests. The base substrate used consisted of coconut mesocarp, white wood sawdust and wheat grain pre-myceliated by the fungus Pycnopurus sanguineus. Analysis by confocal microscopy showed that the fungus produced a network of mycelial hyphae capable of uniting substrate components and incorporated jute. Composites’ mechanical properties were evaluated from three-point bending tests and compression tests. The Shapiro-Wilk tests showed that all determined mechanical properties are normally distributed. The highest compressive resistance (10% deformation) was found in the mycocomposite without jute. The analysis of variance showed that the mean flexural strength of the two configurations analyzed did not present any statistically significant difference; despite this, the composite without jute proved to be more rigid. It was verified that the flexural strength of the produced mycocomposites is located between the values found for the expanded polystyrenes EPS 100 and EPS 150, but that their compressive strength was lower. At first, the materials produced in this work exhibited the necessary properties to be applied in simple pieces such as lampshades, packaging, and plant vases. However, it is still necessary that new studies are carried out to verify the feasibility of its application in the field of engineering, such as in civil construction panels, where EPS are used.


2021 ◽  
Vol 21 (2) ◽  
pp. 260-271
Author(s):  
Renal Renal ◽  
Adyatma Ridwan ◽  
Irpan Ramadhan ◽  
Erni Indrawati

Kebutuhan rumput laut dalam pasar domestik dan pasar internasional terus meningkat sesuai dengan data KKP pada tahun 2020, total produksi rumput laut pada tahun 2018 sebesar 213.422 ton, pada tahun 2019 sebesar 9.900.000 ton. Salah satu rumput laut yang memiliki prospek pemasaran yang cukup luas adalah lawi-lawi. Lawi-lawi Caulerpa lentillifera) merupakan spesies rumput laut hijau yang biasa dikenal dengan sebutan anggur laut dan tersebar di beberapa lautan tropis dan subtropis. Tujuan dari kegiatan ini adalah (1) melakukan kajian literatur budidaya C. lentillifera di tambak dan (2) melakukan kajian peningkatan produktivitas tambak dengan memanfaatkan limbah organik sebagai sumber hara tambak. Metode yang digunakan dalam pelaksanaan kegiatan ini adalah melakukan literatur review, yaitu sebuah pencarian literatur baik nasional maupun internasional yang dilakukan dengan mereview jurnal, skripsi online dan buku. Berdasarkan hasil review dari 16 kajian yang didapat dari berbagai sumber, diantaranya 16 Jurnal (11 Jurnal Nasional dan 5 Jurnal Internasonal), 2 Skripsi Online dan 2 Buku didapatkan bahwa ada beberapa hal yang mempengaruhi pertumbuhan C. lentillifera yaitu, penggunaan zat pengatur tumbuh, bobot awal yang berbeda, salinitas dan jenis substrat dasar, ketersediaan unsur-unsur hara di tanah dan air, serta kedalaman yang berbeda The need for seaweed in the domestic market and the international market continues to increase according to KKP data in 2020, the total seaweed production in 2018 is 213,422 tons, in 2019 it is 9,900,000 tons. One of the seaweeds that has broad marketing prospects is lawi-lawi. Lawi-lawi Caulerpa lentillifera) is a species of green seaweed commonly known as sea grape and is distributed in several tropical and subtropical oceans. The objectives of this activity were (1) to study the literature on C. lentillifera cultivation in ponds and (2) to study the increase in pond productivity by utilizing organic waste as a source of pond nutrients. The method used in the implementation of this activity is to conduct a literature review, which is a literature search, both national and international, which is carried out by reviewing journals, online theses and books. Based on the results of reviews from 16 studies obtained from various sources, including 13 journals (8 National Journals and 5 International Journals), 1 Online Thesis and 1 Book, it was found that there were several things that influenced the growth of C. lentillifera, namely, the use of growth regulators, weight different bases, salinity and type of base substrate, availability of nutrients in soil and water, and different depths.


2021 ◽  
Vol 17 (2) ◽  
pp. 09-15
Author(s):  
Neisiany Rebelo Pimentel ◽  
Daniela Pauletto ◽  
Àdria Fernandes da Silva ◽  
Thiago Gomes da Silva Oliveira ◽  
Orlanilson da Silva Brito

Moringa oleiferaLam., known as moringa, is an arboreal plant belonging to the Moringaceae family, native to India,and has a high capacity to adapt to climatic conditions and arid soils. In this study we evaluated the initial development of seedlings of M. oleiferaLam. under different substrates conditions. The experiment was conducted in a completely randomized design, consisting of eight treatments resulting from combinations of the base substrate (85% soil, 3% carbonized rice straw and 12% coconut fiber). At 60 days after sowing, plant height, stem diameter, dry mass of the aerial part and root system, total dry mass were evaluated, in addition to the Dickson quality index (IQD). The best seedling growth occurred using the combination of 20% poultry litter and 10% bovine manure. Seedlings produced with substrates formulated with 20% poultry litter and 10% bovine manure showed gains in the evaluated variables, which could be a viable alternative for the production of moringa seedlings.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2240
Author(s):  
Satoshi Horikoshi ◽  
Yuhei Arai ◽  
Nick Serpone

This study used controlled microwaves to elucidate the response of adhesive components to microwaves and examined the advantages of microwave radiation in curing epoxy adhesives. Curing of adhesives with microwaves proceeded very rapidly, even though each component of the adhesive was not efficiently heated by the microwaves. The reason the adhesive cured rapidly is that microwave heating was enhanced by the electrically charged (ionic) intermediates produced by the curing reaction. In contrast, the cured adhesive displayed lower microwave absorption and lower heating efficiency, suggesting that the cured adhesive stopped heating even if it continued to be exposed to microwaves. This is a definite advantage in the curing of adhesives with microwaves, as, for example, adhesives dropped onto polystyrene could be cured using microwave heating without degrading the polystyrene base substrate.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4743
Author(s):  
Marta Michalska-Domańska ◽  
Magdalena Łazińska ◽  
Justyna Łukasiewicz ◽  
Johannes M. C. Mol ◽  
Tomasz Durejko

The anodization of commercially pure Ti alloy (99.5 wt %) and two biomedical titanium alloys, Ti6Al7Nb and Ti6Al4V, was performed, and the resulting anodic oxides were studied. The biomedical alloys were made by Laser Engineered Net Shaping. The glycol-based and glycerol-based electrolytes with 0.3 M ammonium fluoride and 2 wt % of deionized water content were tested. It was found that electrolyte type as well as the chemical composition of the base substrate affected the final morphology and chemical composition of the anodic oxide formed. A higher current density, ionic mobility, and oxide growth rate were obtained in glycol-based electrolyte as compared to those obtained in glycerol-based electrolyte for all tested alloys. A self-organized nanotubular and nanoporous morphology of the anodic oxide in both types of electrolyte was obtained. In each electrolyte, the alloy susceptibility to oxidation increased in the following order: Ti6Al4V < Ti 99.5% < Ti6Al7Nb, which can be correlated to the oxidation susceptibility of the base titanium alloy. It was observed that the more impurities/alloying elements in the substrate, the lower the pore diameters of anodic oxide. There was a higher observed incorporation of electrolyte species into the anodic oxide matrix in the glycerol-based electrolyte compared with that in glycol-based electrolyte.


Nativa ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 643-649
Author(s):  
Antonio Henrique Cordeiro Ramalho ◽  
Fernanda Dalfior Maffioletti ◽  
Paulo André Trazzi ◽  
Eduardo Cordeiro Ramalho ◽  
Nilton Cesar Fiedler

A produtividade florestal depende das potencialidades genéticas das matrizes, do ambiente proposto pelos substratos, frequência de irrigação, disponibilidade de luz, nutrição e das condições fitossanitárias. Assim, objetivou-se com o presente estudo analisar os efeitos da aplicação de potássio e de irrigação na qualidade de mudas de Eucalyptus urophylla. Para tal adotou-se o delineamento experimental em parcelas subdivididas definindo as 2 lâminas de irrigação (10 mm e 15 mm) como parcelas e os 5 níveis de potássio (0; 1,2; 2,4; 4,8; e 9,6 g L-1) como subparcelas, em 5 repetições compostas por 9 plantas. A comparação entre os métodos foi feita através teste de Tukey com 5% de probabilidade. Aos 120 dias, foram avaliadas: altura da parte aérea, diâmetro do colo, massa seca da parte aérea e da raiz. O tratamento testemunha apresentou as melhores médias em todos os parâmetros, sendo considerado o mais eficiente. A lâmina de irrigação de 15 mm foi considerada a mais eficiente. Portanto, conclui-se que qualquer que seja o incremento de potássio na produção de mudas, o mesmo deve se relacionar harmonicamente com a quantidade pré-existente no substrato base e com as exigências da cultura, de maneira que haja equilíbrio entre todas as partes. Palavras-chave: manejo hídrico; rustificação; substrato; casa de sombra.   IRRIGATION AND POTASSIUM LEVELS IN THE QUALITY OF EUCALYPTUS   ABSTRACT:  Forest productivity depends on the genetic potential of the matrices, the environment proposed by the substrates, frequency of irrigation, availability of light, nutrition and phytosanitary conditions. Thus, the aim of this study was to analyze the effects of potassium and irrigation on the quality of Eucalyptus urophylla seedlings. For this purpose, the experimental design was adopted in subdivided plots, defining the 2 layers of irrigation (10 mm and 15 mm) as plots and the 5 levels of potassium (0; 1.2; 2.4; 4.8; and 9.6 g L-1) as subplots, in 5 repetitions composed of 8 plants. The comparison between the methods was made using the Tukey test with a 5% probability. At 120 days, the following were evaluated: height of the aerial part, diameter of the neck, dry mass of the aerial part and the root. The control treatment showed the best averages in all parameters, being considered the most efficient. The 15 mm irrigation blade was considered the most efficient. Therefore, it is concluded that whatever the potassium increase in the production of seedlings, it must be harmoniously related to the pre-existing quantity in the base substrate and to the requirements of the culture, so that there is balance between all parts. Keywords: water management; rustification; substrate; shadow house.


2020 ◽  
Vol 12 (42) ◽  
pp. 47911-47920
Author(s):  
Kazuto Hatakeyama ◽  
Yoshie Ishikawa ◽  
Kazuhiro Kirihara ◽  
Tsuyohito Ito ◽  
Koichi Mayumi ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document