Scientific Analysis and Conservation Treatment on the Buddhist Scriptures of Paper Relics Excavated from Sum Tolgoi, Mongolia

This study analyzed the composition and structure of materials with Buddhist paper scriptures excavated from architectural sites in ‘Sum Tolgoi’ of the 17th century and carried out conservation treatment base on the result of the analysis. The scriptures were covered in dust and foreign sub stances, and were so crumpled that it was impossib le to identify the form. The damage, loss, and discoloration have been identified. Buddhist scriptures written in Tibetan used indigo and ink sticks on paper as a result of UV-Vis analysis, and ink sticks as black character materials from scriptures written ancient Mongolian. SEM-EDS and Micro-XRF analyses revealed that the outlines were drawn with red lines using a mix of Minium (Pb3O4) and Cinnabar (HgS), or Cinnabar (HgS) alone, and the contents of the scriptures were written with silver paint. Silver chloride (AgCl) and Calcium (Ca) were identified in the silver paint component of the characters, while Calcium and Orpiment (As2S3) were identified in the yellow lines. Concerning the paper ground, Buddhist scriptures written in ancient Mongolian were characterized by herbal plant fiber and bast fiber, and those written in Tibetan, by bast fiber. Radiocarbon dating indicates that the paper for the scriptures was produced b etween the 15th and 17th centuries. Conservation treatment of the scriptures was carried out based on the experiment on the production of pre-coated paper and how to coat that to prevent the second damage due to the deformation and fragility of the excavated paper. The scriptures were preserved and mounted, and a neutral box was made to identify the contents of the scriptures recorded on both sides after the treatment. This conservation treatment is the result of a study that applied new conservation treatment materials and methods according to the principle of conservation treatment reversibility.

3D-Printed Metasurface Units for Potential Energy Harvesting Applications at the 2.4 GHz Frequency Band

The capability of three-dimensional printed cut-wire metasurfaces to harvest energy in frequencies around 2.4 GHz, is studied in this paper. Cut-wire metasurfaces were constructed using the Fused Filament Fabrication technique. In particular, two metasurfaces, consisting of different materials were produced. The first was constructed using Polylactic Acid as starting material. Then, the printed metasurface was covered with a thin layer of conductive silver paint, in order to achieve good electrical conductivity. The other metasurface was built using commercially available, conductive Electrifi. Both metasurfaces exhibit good energy harvesting behavior, in the frequency band near 2.4 GHz. Their harvesting efficiency is found to be almost three times lower than that obtained for conventional PCB-printed cut-wire metasurfaces. Nevertheless, all of the experimental results presented here strongly corroborate that three-dimensional-printed metasurfaces can be potentially used to harvest energy in the 2.4 GHz frequency band.

Rupture of alumina coatings on C35 steel: A numerical simulation

The knowledge of the rupture mechanism of multilayer systems is necessary for improving the bonding of materials, particularly for the ceramic-to-metal junctions, and especially in the case of the ceramic coatings on metallic substrates. For this purpose, coupling experimental measurements of macroscopic interfacial adhesions with numerical tools of fracture mechanics allow understanding how the stress distribution and the cracking mechanisms are influenced by the local environment. This brings an explanation to the cracks initiation and propagation and to the role of local characteristics of the interfacial zone. The present work illustrates this, in the case of alumina coatings strongly bonded to C35 steel substrates previously pre-oxidized in CO2. The experimental tool is based on the “silver print test”. It consists in covering the central part of the samples with a thin layer of silver paint before coating in order to create a defect zone. Concerning the numerical part, the finite element method is used as a powerful tool to describe the mechanical phenomena at the local scale influencing the crack propagation. The obtained numerical results show a good agreement with the experimental observations and they allow a local description of the phenomena influencing the cracking mechanism. Moreover, they lead to a concrete proposition for improving the coatings adherence.

Simple Controlling Ecofriendly Synthesis of Silver Nanoparticles at Room Temperature Using Lemon Juice Extract and Commercial Rice Vinegar

Silver nanoparticles were prepared in an ecofriendly manner at room temperature via the stepwise-modified Tollens route using the lemon juice extract and commercial rice vinegar. In this work, the lemon juice extract—a natural-origin chemical—was used as a reducing and stabilizing agent, and commercial rice vinegar was used to create a low acidic environment to control the silver nanoparticle growth via the stepwise method. The average dimension of silver nanoparticles was qualitatively evaluated through the UV-Vis spectra via the Mie theory. The X-ray diffraction and field emission scanning electron spectroscopy were employed to study the purity, the crystal structure, and the morphology of samples, respectively. Due to the weak activity and low purity of ecofriendly chemicals, the reaction and baking times strongly affect the preparation efficiency in obtaining small-size silver nanoparticles (∼40 nm). The highest efficiency was obtained with 24 h reaction time and 48 h baking time. The bimodal distribution of the size of silver nanoparticles was observed by UV-Vis analysis and field emission scanning electron microscopy. The obtained small-size silver nanoparticles (∼40 nm) have a uniform dimension. The quality of the obtained silver nanoparticles was evaluated through the conducting properties of silver paint made from ecosynthesized silver nanoparticles which showed a promising prospect to develop green-synthesized silver paint working at room temperature.

Whole Virus Detection using Paper Potentiometry

Paper-based sensors, microfluidic platforms and electronic devices have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper aptamer-based potentiometric sensor to detect the whole Zika virus for the first time with a minimum sensitivity of 2.6 nV/Zika and the minimum detectable signal (MDS) of 0.8x1e6 Zika. Our paper sensor works very similar to a P-N junction where a junction is formed between two different wet regions with different electrochemical potentials near each other on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consisted of a 2-3 mm x 10 mm segments of a paper with a conducting silver paint contact patches on its two ends. The paper is soaked in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. Atomic force microscopy studies were carried out to show both the aptamer and Zika become immobilized in the paper. We then added the Zika (in its own buffer or simulant Urine) to the region close to one of the silver-paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10-20 gm weight), became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. The potential measured between the two silver paint contacts reproducibly became more negative as upon adding the Zika. We also showed that an LCD powered by the sensor, can be used to detect the sensor output.

Whole Virus Detection Using Paper Potentiometry and Aptamers

Paper-based sensors, microfluidic platforms and electronic devices have attracted attention in the past couple of decades because they are flexible, can be recycled easily, environmentally friendly, and inexpensive. Here we report a paper aptamer-based potentiometric sensor to detect the whole Zika virus for the first time with a minimum sensitivity of 2.6 nV/Zika and the minimum detectable signal (MDS) of 1.2x106 Zika. Our paper sensor works very similar to a P-N junction where a junction is formed between two different wet regions with different electrochemical potentials near each other on the paper. These two regions with slightly different ionic contents, ionic species and concentrations, produce a potential difference given by the Nernst equation. Our paper sensor consisted of a 2-3 mm x 10 mm segments of a paper with a conducting silver paint contact patches on its two ends. The paper is soaked in a buffer solution containing aptamers designed to bind to the capsid proteins on Zika. Atomic force microscopy studies were carried out to show both the aptamer and Zika become immobilized in the paper. We then added the Zika (in its own buffer) to the region close to one of the silver-paint contacts. The Zika virus (40 nm diameter with 43 kDa or 7.1x10-20 gm weight), became immobilized in the paper’s pores and bonded with the resident aptamers creating a concentration gradient. The potential measured between the two silver paint contacts reproducibly became more negative as upon adding the Zika. We also showed that an LCD powered by the sensor, can be used to detect the sensor output.

An enameled wire with a semi-conductive layer: A solution for a better distibution of the voltage stresses in motor windings

The paper analyzes a possible improvement of Pulse Width Modulation (PWM) fed motor insulation according to a principle developed by the high voltages industry. The proposed principle consists in using a specific enameled wire made with an additional semi-conductive layer on its outer surface. Experimental study is realized in order to measure Partial Discharges (PDs) activity with three technologies: Classical enameled wire, enameled wire with an external conductive layer (silver paint) and enameled wire with an external semi-conductive layer (2% of carbon nanoparticles). Simulations are made in order to understand the behavior of the new semi-conductive wire.

Silver nanoparticles in the thermal silver plating of aluminium busbar joints

Thermal silver plating method by means of nanosilver-based paint could be an alternative to electrochemical processes. Electrochemical silver layering on aluminium is typically achieved with an intermediate layer, which provides very good adhesion of the layer to the aluminium surface but increases the resistance of the whole junction system. In the method of silver plating promoted by the authors, the intermediate layer is eliminated. The layer of silver paint was applied directly on the aluminium surface by spraying using aerograph. Procured silver layers, according to ISO 2409, prove proper adhesion to aluminium. The value of contact resistance with a pressure of 300 N cm−2 and current load of 200 A is 0.03 μΩ mm−2, which is comparable to the contact resistance of layers generated by electrochemical means. This new method decreases the level of toxic waste emission and therefore is less harmful for the natural environment. It is also cheaper and simpler than the electrochemical process. An additional advantage is the possibility of silver plating of the chosen surfaces with various shapes.