bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevention of Central Venous Catheter Associated Infections Using Boron Carbon Nitride (BCN) Thin Films
Authors: Nehate Shraddha Dhanraj , Saikumar Ashwin Kumar , Naga Varsha , Sundaram Kalpathy B.
Published: December 2020

Central line-associated blood stream infections (CLABSIs) are the infections caused due to use of central venous catheters in patients. Implanted catheters are susceptible to bacterial colonization, biofilm formation and consequently resulting in infection. CLABSIs continue being important and preventable health-care related infection. Of all the healthcare associated infections, CLABSIs make up to 250,000 cases per year in the US with mortality of up to 35% [1]. Additionally, these infections are associated with high hospital stay durations leading to extremely high cost burden accounting to ~$46,000 per case [2]. However, central venous catheters are imperative in delivery of fluids and medications and to monitor the patient health. Current approach to mitigate this problem heavily focusses on deposition of coatings, inhibiting bacterial adhesion and reducing biofilm formation.

In this study, boron carbon nitride (BCN) coatings will be incorporated on central venous catheters for the first time. Boron carbon nitride (BCN) films have achieved attention owing to their crystal structure and unique properties. BCN compounds are expected to combine excellent properties of diamond, boron carbide and boron nitride with their properties adjustable depending on their composition and structure[3]. B-C-N ternary compounds have been reported previously for biological applications [4-7]. Influence of BCN coating on bacterial colonization of gram-positive and gram-negative bacteria will be investigated. BCN films will be deposited using RF sputtering technique.

References

[1] S. S. Magill et al., "Changes in prevalence of health care–associated infections in US hospitals," New England Journal of Medicine, vol. 379, no. 18, pp. 1732-1744, 2018.

[2] Y. Haddadin and H. Regunath, "Central line associated blood stream infections (CLABSI)," in StatPearls [Internet]: StatPearls Publishing, 2019.

[3] A. Prakash, S. D. Nehate, and K. B. Sundaram, "Boron carbon nitride based metal-insulator-metal UV detectors for harsh environment applications," Optics letters, vol. 41, no. 18, pp. 4249-4252, 2016.

[4] W. Yang, P. Thordarson, J. J. Gooding, S. P. Ringer, and F. Braet, "Carbon nanotubes for biological and biomedical applications," Nanotechnology, vol. 18, no. 41, p. 412001, 2007.

[5] A. Bianco, K. Kostarelos, C. D. Partidos, and M. Prato, "Biomedical applications of functionalised carbon nanotubes," Chemical Communications, no. 5, pp. 571-577, 2005.

[6] S. H. Mir, V. K. Yadav, and J. K. Singh, "Boron–Carbon–Nitride Sheet as a Novel Surface for Biological Applications: Insights from Density Functional Theory," ACS Omega, vol. 4, no. 2, pp. 3732-3738, 2019.

[7] G. Ciofani, S. Danti, G. G. Genchi, B. Mazzolai, and V. Mattoli, "Boron nitride nanotubes: biocompatibility and potential spill‐over in nanomedicine," Small, vol. 9, no. 9‐10, pp. 1672-1685, 2013.
Development of Low Power Consumption Electrochromic Device Using Spontaneous Discoloration Reaction
Authors: Tsukada Kenichi , Abe Hiroya , Nishizawa Matsuhiko , Kato Takehito
Published: December 2020

Recently, dimming functional materials have been attracted attention as one of the solutions to energy problems. Dimmable materials are capable of continuously adjusting the transmittance of light according to the intensity of external light, which is expected to reduce cooling and heating loads of buildings such as houses and office buildings and realize energy saving. Prussian blue (PB, KFe3+[Fe2+(CN)6]) is known as one of the dimming functional materials that shows reversible color changes upon Fe2+/Fe3+ redox reaction [1], and has been used for electrochromic devices (ECD) as an inexpensive and highly durable dimming function material. The conventional ECD is controlled by bipolar voltage applications for coloration and discoloration [2]. In contrast, , we developed here the ECD equipping a function of a spontaneous discoloration without applying voltage with the aim to reduce power consumption.

ECD is consisted of indium-doped tin oxide (ITO) glass / PB / electrolyte / PB / ITO glass. The PB-coated ITO glasses were prepared by casting PB ink onto ITO glasses (15 x 15 mm) and spin-coated at 2000 rpm for 10 sec. The electrolyte used was a propylene carbonate containing potassium bis(trifluoromethanesulfonyl)imide and polymethyl methacrylate.

By applying the voltage at 1.5 V to the ECD, the wavelength peak of a reflected light shifted from 460 nm (blue color) to 535 nm (yellow color) due to the reduction and oxidation of PB on the anode and the cathode, respectively. That is, KFe3+[Fe2+(CN)6] (blue) was reduced to K2Fe2+[Fe2+(CN)6] (colorless) on a cathode and KFe3+[Fe2+(CN)6] (blue) was oxidized to KFe3+[Fe3+(CN)6] (yellow) on an anode. After removing the voltage application, wavelength shifted back from 535 nm to 500 nm, indicating that PBs spontaneously changed to their original states. It is estimated that the color returns to the original color in about 3 hours. The spontaneous discoloration might be caused by the potential difference between the electrodes. The detailed discussion regarding the relationship between spontaneous discoloration and the elapsed time will be present.

[1] K. Yoshino, “Prussian Blue; New applications and its nanoparticles,” THE CHEMICAL TIMES, 229(3):23-27, (2013)

[2] H. Tanaka, (2010), “Development of electrochromic devices by printing processes,” NEW GLASS, 25(3): 60-63, (2010)

Figure 1
Carbochlorination of Cobalt Oxide and Electrochemical Recovery of Co in an Amide-Type Ionic Liquid
Authors: Yeh Hsing-wen , Serizawa Nobuyuki , Katayama Yasushi
Published: December 2020

Recycle of rare metals from electric devices is demanded from the viewpoints of production costs and environmental protection. Carbochlorination is a traditional pyrometallurgical process to convert metal oxides in metal waste into metal chlorides. However, high temperature is often required for the carbochlorination process, leading to an increase in the recycling cost. We have already reported that the dissolution of palladium oxide was possible in an amide-type ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA) containing BMPCl by carbochlorination at a relatively lower temperature. In the present study, the carbochlorination of cobalt oxide (CoO) was investigated in BMPTFSA containing BMPCl. Recovery of Co was also attempted by electrochemical reduction of the cobalt species in the ionic liquid.

CoO was reacted with some carbochlorination reagents in 0.5 M BMPCl/BMPTFSA in a perfluoroethylene propylene copolymer (FEP) tube at 150 °C for 24 h. The residual carbochlorination reagents and byproducts were removed by heating under vacuum at 100 - 150 °C for 24 h. The electrochemical measurements were conducted using a single-compartment cell using glassy carbon as a working electrode, cobalt as a counter electrode, and silver wire immersed in 0.1 M AgCF3SO3/BMPTFSA isolated from the sample electrolyte with porous glass as the reference electrode.

CoO was insoluble in 0.5 M BMPCl/BMPTFSA without the carbochlorination reagents. CoO was found to be dissolved as [CoCl4]2– in 0.5 BMPCl/BMPTFSA in the presence of the carbochlorination reagents at 150 °C by the ultraviolet-visible spectroscopy. A cathodic current peak assignable to the reduction of [CoCl4]2– was observed at -3.1 V in the cyclic voltammogram of a GC electrode in the ionic liquid after carbochlorination of CoO. The deposits containing Co were obtained by the potentiostatic cathodic reduction in the ionic liquid, suggesting the recovery of Co from CoO is possible electrochemically with carbochlorination at low temperature.
Study on the Prevention of Optics Contamination in Photo-Lithography
Authors: Jung Juyoung , Choi Byoung Deog
Published: December 2020

In semiconductor manufacturing technology, photolitho exposure tools have advanced scaling of integrated circuit (IC) chips for decades. The tools enable illumination optics to expose the patterns of photo-mask onto wafers coated with photo-resist (PR). As the line width of the chip has been scaled down below 20 nm, the contamination of optics degrades the uniformity of light so that it reduces the accuracy of optical patterns. Thus, contamination in the optic system is crucial to enhance wafer pattern scaling.

The level of contamination in optics can be identified with light scattering (i.e., Straylight index). By tracing the Straylight index for years, we determined REMA (Reticle Masking) lens, which is one of the lens element, was contaminated by the chemical ions of FAB air. We implemented destructive inspection with the contaminated lenses to identify degradation mechanisms and detected plenty of positive ions (i.e., Si+) (Table.1) and negative ions (i.e., Silicon Oxide) (Table.2) on REMA Lens. (Fig.1). The humidity in FAB air which is attach to the polar surface of optics, light exposure transforms it to hydroxide ions or highly reactive radical (OH*, H*, O*) by the DUV light. And then the highly reactive radical is easy to combine with non-cleanable contamination (e.g., silicon, sulfur, and nitrogen). Although Photolithographic tools have a purging system using inert N2, XCDA (Extreme clean dry air), CA (Clean Air) to prevent contamination. Each optic has a different purge system and environment, so contamination has been strongly concentrated on the last lens element of REMA.

In this paper, we performed three main tests to slow the rate of lens contamination. First of all, literally hundreds of tools in the factory have measured with the efficiency of the chemical filters for pollutions. Then, we exchanged types of chemical filters based on the different contamination speed. This test helps us to identify contamination sources. Secondly, we changed the air mixing ratio (i.e., Dilution factor). Despite the similar structure of the tool, the air mixing ratio is different respectively as the time of each tools is released. After investigating the three different values, we found an optimized value to slow down the contamination speed. Lastly, we reform the structure of tools to avoid mixing the pollution air. Overall, these test results tell a remedy of how to manage the lens contamination in optics.

Figure 1
Electrical Properties of SiGe/W Plate Node in DRAM Capacitor
Authors: Lee Yongyeol , Choi Byoung Deog , Jung Ilwoo
Published: December 2020

Recently DRAM(Dynamic Random Access Memory) industry is continuously scaling down to improve productivity and create low power memory products. This trend reduces the capacitance for storing data and increases the unwanted parasitic capacitance, which causes problems in data storage of DRAM. In addition, the plate structure of the node on the current DRAM capacitor further reduces the data storage capacity by causing voltage noise during product operation.

In this paper, electrical properties were evaluated using SiGe/W(tungsten) structure instead of the existing SiGe(silicon germanium) plate, based on the fact that when the resistance of the plate node on the capacitor decreases, the plate noise can be improved during product operation by RC model. W was deposited on the high-doped SiGe by PVD(Physical Vapor Deposition), and it was confirmed that an Ohmic contact between SiGe and W was formed. Sheet resistance and contact resistance were decreased by 86.6% and 51.1%, respectively, compared to the existing SiGe plate structure under the voltage condition of 3 volts. As a result, it was confirmed that the value of capacitance for storing data increased by 20%. In order to confirm the improvement of failure, we conducted a test that caused plate noise by continuously inversion of adjacent data, and confirmed that the failure was improved by 36% in the SiGe/W plate structure.

Figure 1
Improved Photoelectrochemical Performances of Aqueous Mesoscopic Solar Cells
Authors: Yang Yuke , Zhang Xiao LI
Published: December 2020

Conventional mesoscopic dye-sensitized solar cells using organic solvents based electrolytes generally have the disadvantages of high vapour pressure against reliable encapsulation, and most importantly, are not environmentally friendly. Aqueous electrolytes based on water possess advantages such as low-cost, earth-abundant, non-toxic and non-flammable, therefore, attracted considerable research interests. However, aqueous electrolyte would negatively shift the conduction band of TiO2 as the water molecules irreversibly change the interfacial properties of the sensitized TiO2 film. Tungsten doped (W-doped) TiO2 mesoporous nanoparticle aggregates, possessing high surface area and superior scattering effect, were used for photoanode preparation. The W-doping would induce a positive shift of the TiO2 conduction band, and enhance the driving force for electron injection and collection efficiencies. The electrochemical impedance spectra indicated a retarded charge recombination and increased electron diffusion length after W-doping. Aqueous DSCs produced a significant improved the open circuit voltage of 712 mV and a short circuit current of 7.05 mA·cm-2, leading to an overall increased power conversion efficiency of 3.40% at 1 sun, a nearly 25% enhancement compared to the non-doped photoanode.
Performance Evaluation of Intermediate Temperature Proton-Conducting Soec with BaZr0.6Ce0.2Y0.2O3-δ Electrolyte
Authors: Toriumi Hajime , Kitano Sho , Habazaki Hiroki , Aoki Yoshitaka
Published: December 2020

A solid oxide steam electrolysis cell (SOEC) has attracted much attention for the production of a clean H2 from water by using renewable electricity. Activation energy of proton conduction in proton conducting perovskite oxides BaZr
x
Ce1-x-y
Y
y
O3-δ (BZCY) is much lower than that of yttria stabilized zirconia which is practically used for the high temperature SOECs [1]. Hence the cells using the proton conductors (H+-SOEC) are expected to operate at lower temperatures than that of YSZ-base SOEC. In general, the solid solutions, i.e. BaCe1−x−y
Zr
x
M
y
O3-δ (M = Y, Yb etc.) tend to be more tolerant to CO2 and steam with increasing Zr contents [2], and thus the Zr-rich side BaCe1−x−y
Zr
x
M
y
O3-δ are recently attractive as a practical electrolyte for H+-SOECs. However, the poor sinterability and relatively large grain-boundary resistances retards the application of Zr-rich phase to device application.In this study, we successfully fabricated the thin film electrolysis cells using Zr-rich side BaZr0.6Ce0.2Y0.2O3−δ
(BZCY622) electrolytes. The cathode-supported cells were fabricated by a solid-state reactive sintering method assisted by zinc nitrate sintering additives. The cell comprises of a porous Ni-BZCY622 cermet cathode support, dense electrolyte film with a 20 mm thickness and La0.6Sr0.4Co0.2Fe0.8O3-δ
(LSCF) porous anode. The cells with a 15 nm-thick interlayer of La0.5Sr0.5CoO3-

δ
(LSC) was also fabricated by sputtering deposition of LSC nanofilms on the surface of the electrolyte films before printing LSCF anodes. The cell with and without LSC yielded electrolysis currents of 420 and 200 mA cm-2, respectively, at 1.5 V cell bias at 600 ºC. EIS measurements confirmed that both polarization and ohmic resistances decreased with a use of LSC interlayer, which implies that LSC layer promotes proton transfer at the anode/electrolyte interface and thus reduce the proton transfer resistance and promote anode reactions.

Y. Guo, R. Ran and Z. Shao, Int. J. Hydrogen Energy, 35, 5611, (2010).

P. Sawant, S. Varma, B. N. Wani and S. R. Bharadwaj, Int. J. Hydrogen Energy, 37, 3848, (2012).
Effect on the Ligand of Triruthenium Unit for Hydrogen Evolution Reaction
Authors: Minamoto Hironori , Fukuda Ryunosuke , Daicho Keita , Takamura Kazuki , Kato Jinnosuke , Morino Takashi , Nishiyama Katsuhiko , Yoshimoto Soichiro , Abe Masaaki
Published: December 2020

At present, various energy problems occur on the earth. In order to solve the problems utilization of hydrogen is a candidate. Because hydrogen is a clean and highly efficient energy that does not produce sulfur oxides and nitrogen oxides and is attracting attention as a substitute for primary energy such as petroleum and natural gas. In this study, we focused on the ruthenium cluster unit (1-mer) forming a cyclic structure having three ruthenium ions in a mixed-valence state. Here, we examined a catalytic function of hydrogen evolution reaction (HER) at the 1-mer modified highly oriented pyrolytic graphite (HOPG) electrode. In addition, we have studied effects of alcohol as ligands for 1-mer. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were used for electrochemical measurements. HOPG was modified by drop casting of 0.5 μM 1-mer dichloromethane or methanol solution and used as a working electrode. A Ag/AgCl (KCl sat.) or a reversible hydrogen electrode (RHE) was used as a reference electrode, and a platinum plate was used as a counter electrode. LSV and CV were carried out in 0.1 M HClO4 in the presence of various alcohols such as methanol and ethanol. Figure 1 shows the LSVs of 0.1 M HClO4 at the 1-mer modified HOPG. The surface concentration of 1-mer was cocurated to be 18 nmol cm-2. At the 1-mer modified HOPG electrode, the starting potential of HER was slightly shifted to positive as compared with that of bare HOPG electrode. This means that the 1-mer modified HOPG has a little catalytic activity for HER. On the other hand, addition of alcohol to the system changes drastically the catalytic activity of the HER. Onset potential of HER was shifted to positive by the addition of alcohol. Comparing the current densities in the presence of each alcohol at –0.80 V, the HER current was influenced by the kinds of alcohol. Especially, when methanol was added to the system, the current density of 0.02 A cm-2 at –0.80 V. Although the reason why the catalytic current for HER depends on the type of alcohol is not clear, it may be considered that the THF ligands of 1-mer are substituted by the alcohol used. We have been are studying the effect of surface concentration and nanoscale structure of 1-mer, and the anion of the electrolyte.

Figure 1
In Operando Spectroscopic Study for Durable Ammonia Electrolysis on Platinum
Authors: Kim Haesol , Choi Chang Hyuck
Published: December 2020

Ammonia has recently been considered as a promising energy carrier and a carbon-free fuel. Combining with renewable energy sources, ammonia oxidation reaction (AOR) is crucial reaction for onsite hydrogen-fuel production and electricity generation in future energy scenario. In spite of promising beginning-of-life AOR activity of platinum, its implementation is hampered by vulnerable AOR catalysis. Hence, improved durability is critically needed but challenged by insufficient understanding of its degradation mechanism during NH3 electrolysis. In this work, we study the degradation mechanisms of Pt during AOR catalysis with operando and in/ex situ spectroscopies. Passivation of the Pt surface and complexation of the dissolved Pt ions by NH3 (or NH3 derivatives during AOR) are identified. Such chemical modifications accelerate Pt dissolution by forming stable complex while decelerate Pt redeposition by passivation of Pt surface, which lead to the instable nature of Pt electrocatalysis toward AOR. Based on the potential-resolved investigations, a stable operando potential window and strategy for operating AOR are suggested in this study. The preliminary AOR protocol demonstrates prolonged NH3 electrolysis without significant degradation of Pt, which implicates the possible usage of NH3 as an energy carrier when the proposed operation strategy is further developed.
Optimization of Boron-Doped Diamond Thin-Layer Cell for Chemical Oxygen Demand Sensor Based on Anodic Oxidation of Organics
Authors: Latifah Dian , Ilhwan Oh
Published: December 2020

The advanced electrochemical oxidation process (AEOPs) has been considered as an appealing approach to overcome problems associated with the conventional water treatment methods. The use of expensive and toxic chemical oxidizing reagents in chemical oxygen demand, for example, can lead to environmental concerns of the production of secondary pollution. Anodic oxidation, one of the most popular AEOPs, offers a rapid and straightforward COD determination by removing the need for chemical oxidants. The process mainly relies on the anode material to degrade the organic molecules; thus, choosing the appropriate material is one of the keys to a successful electrochemical oxidation.

Numerous electrochemical applications utilize boron-doped diamond as the anode material due to its unique properties such as wide potential window, low background current, and resistance to fouling. The employment of BDD for anodic oxidation of organics enables complete oxidation of organics via physically adsorbed hydroxyl radicals (●OH). The species offers a high standard redox potential of E° (●OH/H2O) = 2.80 V/SHE, high reactivity, and short lifetime, makes it possible to be used for the on-site electrochemical oxidation process.

The objective of this study is to develop and optimize an electrochemical system for chemical oxygen demand determination based on a photoelectrochemical degradation principle. The degradation of phenols takes place in a specially designed BDD thin-layer electrode, and the amount of electrons transferred at the electrode can be measured to define the equivalent COD value. A 60μm thick films are used as a spacer, resulting in a contact area of 3 cm2. At 2.54 V vs. SHE, a sample containing 50 mg/L analytes required less than 3 mins to degrade, and the assay time for organics decay increases for a higher concentration of phenols. Incorporating the BDD electrode with cathode materials, such as Pt-coated indium tin oxide (ITO), will be employed as an attempt to improve the degradation efficiency by minimizing the voltage drop between the electrodes. Sandwiching the BDD-cathode using Nafion® membrane will be studied to remove the need for additional supporting electrolytes. The major experimental conditions of the anodic oxidation of organic molecules by BDD, such as applied potential bias, supporting electrolyte concentration, pH, and dissolved oxygen concentration, will be varied to obtain the optimum conditions.
(Invited) 3D Printing of Soft-Matter Mono Pump in Infant Ventricular Assist Device (VAD) for Blood Pumping
Authors: Yeh Yee Cheng , Yamada Naoya , Watanabe Yosuke , Shiblee MD Nahin Islam , Ogawa Jun , Khosla Ajit , Kawakami Masaru , Akamatsu Teruaki , Furukawa Hidemitsu
Published: December 2020

We want to develop a soft-matter Mono pump for infant Ventricular Assist Device (VAD). In this research, we have developed the Mono pump, which is made of soft materials and hard materials to study the effect of applying the soft materials to the Mono pump. The stator of the 3D printed Mono pump was made with biocompatible soft materials called Inter Cross-linking Network (ICN) gels. We believe that ICN gels have not only specific toughness and low friction but also excellent biocompatibility that can prevent blood cell trauma and the transplant rejection. Moreover, the rotor is made of hard materials using commercial resin or filament based 3D printers, (Form 2 and Flashforge Creator). Finally, we will compare the practical and theoretical displacement from the flow rate measurement to implement the best performance of the Mono pump in practical use.

Figure 1
(Invited) Development of Ionic Porous Polymer for Sensing Applications
Authors: Ahmed Kumkum , Furukawa Hidemitsu , Naga Naofumi
Published: December 2020

Porous polymers with macr/micro- sized pores have potential applications in separation, batteries, fuel cells and sensors [1, 2]. Thiol-ene "click" is a widespread method for monolith preparation owing to its exceptional versatility, simplicity and facile tunability. In our previous work, we reported on the fabrication of extremely soft type thiol-ionic gels (T-IGs) incorporating ionic liquid (IL) (70–85 wt%) in the thiol–ene network of thiol-based end-crosslinker and acrylate monomers [3, 4]. The T-IGs exhibited tunable mechanical and conductive properties and conductivity as high as 5.40 mS cm−1 is attained for longer acrylate group containing gels at room temperature. In this work we developed a series of porous polymers through polymerization induced phase separation by utilizing thiol-ene reaction between multi-functional thiol monomers and diacrylate crosslinkers in ionic Liquid solvent medium. The matrix of the polymers constructed of interconnected micro-globules forming a three-dimensional network. These microporous polymers exhibited tunable mechanical prosperities and morphology. In contrary to the ionic gels, the porous structure with entrapped ILs exhibited high ionic conductivity possibly due to relatively unperturbed transport of ions within the interconnected polymer particles compared to the bulk polymeric network. Physical properties of these porous ionic polymers have been investigated to optimize suitable condition for best performance in piezoresistive sensors (enabling sensing of both pressure and strain). This work is expected to add potential functionality in the applied field of the polymer materials.

References

Sakakibara, K., Kagata, H., Ishizuka, N., Sato, T., Tsujii, Y. Fabrication of surface skinless membranes of epoxy resin-based mesoporous monoliths toward advanced separators for lithium ion batteries. J. Mater. Chem. A, 5, 6866–6873 (2017).

Liu, Z., Ou, J., Zou, H., Click polymerization for preparation of monolithic columns for liquid chromatography. Trends Anal. Chem., 82, 89–99 (2016).

Ahmed, K., Naga, N., Kawakami, M. & Furukawa, H. Development of ionic gels using thiol-based monomers in ionic liquid. 9800,980005 (2016).

Ahmed K, Naga N., Kawakami M. and Furukawa H., Extremely Soft, Conductive and Transparent Ionic Gels by 3D Optical Printing, Macromol. Chem. Phys., 1800216 (2018).
(Invited) Friction Processing and Application to High Strength Hydrogel Surface
Authors: Wada Masato , Yoshida Kazunari , Furukawa Hidemitsu
Published: December 2020

In the medical field and food manufacturing process, labor costs and manufacturing costs are reduced, delivery times are shortened, and production is streamlined in all aspects. In particular, the slider part uses many consumables that have a negative effect on the human body and the environment. In this research, we aim at the low friction surface of the functional gel that realizes human safety and cost reduction by replacing a part of the functional gel with the functional gel. This technique involves laser cutting the gel, and the method of creating the sliding and gel surfaces comes from the method of creating a low friction surface by texturing. The textured surface swells uniformly and the coefficient of kinetic friction was measured by the ball-on-disk friction test.

The friction force was measured and the coefficient of friction of the untreated and laser treated DN gel surface was calculated. The results show that laser machining (finishing) can reduce the coefficient of friction. Observation of the gel surface suggests that the cause of friction reduction is a change in the roughness of the gel surface due to laser processing. This finding is expected to guide us to a better understanding of the physicochemical properties of hydrogels. We will introduce an example of using this technology as a machine element.

The dynamic friction coefficient of the low friction gel surface prepared by this method was about 1/3 of that of the untreated gel surface. It was also confirmed that wear marks disappeared depending on the degree of texturing.

Using this technique, it can be easily applied to gel surfaces with low friction. We also designed and developed a unique friction tester for machines. Furthermore, by replacing the metal sliding part with a gel mechanical material, we succeeded in miniaturizing the ultrasonic diagnostic equipment.

Figure 1
(Invited) Research on the Ship Exhaust Emissions Measurement Techniques in Port Water
Authors: Peng Xin , Xiao Changshi , Wen Yuanqiao
Published: December 2020

Ship emissions are the main contributor of air pollution in coastal ports. National governments introduced regulations for limiting ship exhaust emissions in port waters and reducing their effect on the environment. The effective measurement approaches of ship emission are the key to implement limitation policies effectively. The mainstream methods of monitoring ship emission are the sniffing method and optical method (i.e. DOAS, LIDAR, and UV-Camera). In this study, the sniffing monitoring instruments were installed on the port and helicopters to measure the air pollutants emitted from navigating ships in port waters. The land-based sniffing monitoring system consists of two parts, which are hardware and visualization platform. The hardware includes four gas monitoring sensors (CO2, CO, SO2, and NOX), Automatic Identification System (AIS), micro metrological station. The hardware part of land-based sniffing system can provide the dynamic data of ships (i.e. ship speed, navigational state, and location), environmental meteorological data (wind speed, wind velocity, pressure, rainfall), and the concenteation of gas pollutants of ships. The system achieves coarse screening of suspected high-emission ships. The monitoring information about ships is visualized on the visualization software platform. Comparing the simulated theoretical concentration of gas pollutants obtained from the CALPUFF atmospheric pollutant diffusion model under the same environmental conditions, the monitoring feasibility and accuracy of the sniffer shore-based automatic monitoring system are verified. We designed and installed the UAV-based gas sensors monitoring system and measurement the ship exhaust emissions in Yantian port. Comparing the standard errors of simulated FSC values and laboratory FSC (Fuel Sulfur Content) values, the system shows high efficiency and reliability in tracking the FSC of ships.
(Invited) Material Development and Equipment Improvement for 3D Gel Printing Using a Commercially-Available Stereolithography Printer
Authors: Sato Yosuke , Saito Azusa , Watanabe Yosuke , Shiblee MD Nahin Islam , Ogawa Jun , Khosla Ajit , Kawakami Masaru , Furukawa Hidemitsu
Published: December 2020

Hydrogels are known as a soft and water-rich material, and they are widely applied in the medical and industrial fields. On the other hand, when a liquid material is poured into a mold to make a gel, it is generally difficult to form a complicated shape due to the shape restriction included in the mold. To overcome this challenge, we have independently developed the 3D gel printer "SWIM-ER". This gel printing can make very complex structures that is unable to create by the hydrogel molding process. The our previous works includes soft robots for teaching, research, and surgical simulation and applications of 3D-printed organ models in hydrogel.

However, it should be pointed out that due to the high economic cost, this printer is not popular. This study proposes an inexpensive gel printing technology using a commercially available stereolithography 3D printer equipped with liquid crystal display (LCD) or digital light processing (DLP) technology for UV irradiation. The price of a commercial 3D printer for general use ($500) is much cheaper than the price of a 3D gel printer. We have confirmed that our proposed method can perform three-dimensional modeling of gel by photopolymerization reaction under excitation of 405 nm.

Figure 1
Self-Assembly Directed Organization of Fullerene-Bisporphyrins into Supramolecular Donut Structures for Excited State Charge Stabilization
Authors: Caballero Ruben , de la Cruz Pilar , Ortí Enrique , Aragó Juan , Cerdá Jesús , Barrejon Myriam , Seetharaman Sairaman , Langa Fernando , D'Souza Francis
Published: December 2020

Supramolecular structures formed from intermolecular association of repeated units of redox- and photo-active molecular monomers, in solution or in bulk, are of greater significance due to their importance in biology performing various functions making life on earth possible. One such supramolecular organization is ‘photosynthetic antenna-reaction centre’ complex found in green plants and bacteria which is involved in converting sunlight into chemical energy. The core antenna complex in bacteria form concentric rings, LH1 and LH2. LH1 consists of 16 ab protomers with a 68 Å hole in the middle while the LH2 consists of 9 ab protomers. These work in synergy in terms of light capture, transport and generating charge separated states.

Several covalent and supramolecular structures containing fullerenes have been described in literature, however, only a few examples where the components are either redox or photochemically amphoteric. This property becomes especially important in light energy harvesting where the presence of an electron donor-acceptor pair is a basic necessity with at least one of them being photo-active to promote photoinduced charge separation leading to the formation of radical ion-pairs. Here, we describe the synthesis, by tether-directed functionalization, of a [60]fullerene
e
-bisadduct carrying two Zn-porphyrins (see figure inset), its supramolecular organization, and photophysical events. Remarkably, the supramolecular assembly of the present bisporphyrin-C60 forms donuts-shape aggregates (see figure for AFM image), primarily via pi-pi type charge transfer interactions, as demonstrated by means of optical absorption and emission, variable temperature 1H NMR and AFM and supported by theoretical calculations. More importantly, upon photoexcitation, the supramolecular assembly generates long-lived charge separated states of ~1 ms lifetime due to electron/hole delocalization within the supramolecular structure. The unprecedented results of the present study demonstrate the success of supramolecular organization of donor-acceptor pairs in biomimetic light energy harvesting.

Figure 1
Free Standing Porous Graphene and Reduced Graphene Papers Manufactured from Sedimentation of Arc Discharge of Graphite Rods
Authors: Dada Oluwaseun John
Published: December 2020

Free Standing Porous Graphene and Reduced Graphene Papers manufactured from Sedimentation of Arc Discharge of Graphite Rods. At SignEcoTech, novel and newer nano-carbons such as hard carbons, homogenized graphene, low defect highly crystalline graphene’s, and wrinkled graphene [1-14]. Here, Graphene Oxide papers have been synthesized previously by flow-directed assembly, where the pressure of air within the assembly supports graphene oxide sheets in their nano-crystalline colloidal solution being filtered on nano-porous filter paper. However in this research, we haven’t used any filter paper, or directed flow assembly, but sedimentation of the colloidal solution in ethyl alcohol in a dish. Then, the wrinkled the hierarchical GO sheets fall under gravity by sedimentation. Wrinkling in GO was enhanced by low defects, multi-layer clusters, and variegated + edge interaction amongst graphene clusters, as such the sedimented graphene papers were porous, intertwined and free standing. The composition of GO was confirmed by XPS, while the low defect level clearly marked by higher planar order and low ID/IG band. The wrinkled, multilayer clusters and carbonic surface properties of the graphene oxide sheets enhanced fast sedimentation, evaporation of the alcohol and formation of porous GO structure. The porous reduced\GO morphology is captured by optical microscope.

Keywords: Wrinkled GO Papers, Reduced Graphene, Arc Discharge, Modified Hummers Method
Development of Silica Nanoparticles Based Nontoxic, Transparent SUPER Hydrophobic Coatings
Authors: Ullah Nehar
Published: December 2020

Research work on the advancement of super hydrophobic surfaces exhibits promising applications. Among them, one of the major applications is to make the surfaces more corrosion-resistant in order to enhance the long-term chemical and mechanical stability and durability of the surface. Current research work is focused on the development of transparent, corrosion resistant and modified Super Hydrophobic Coatings. The coated samples were prepared and the contact angles of water droplets on the surface were measured to check their wettability. Moreover, the self-cleaning properties of these super hydrophobic surfaces fabricated by various methods and their chemical and mechanical stability was investigated. Transparent Superhydrophobic coatings were developed by using Silica Nanoparticles and Polyvinyl alcohol(Polymer). Silica Nanoparticles were first synthesized by Stober process and then were functionalized to create surface roughness on them by using a coupling agent "Trichloro(methyl)silane". The modified Silica Nanoparticles were then associated with a mixture of PVA and MEK (methyl-ethyl ketone). Durability and hydrophobicity of the developed coatings on different surfaces were examined. The mean contact angle between the coated surface and water droplets was measured to be more than 170o. Samples that were associated with PVA (polyvinyl alcohol) shows the best results for super hydrophobicity and durability of the coating. The potential of the functionalization sparks the idea of possible functionalization of silica nanoparticles using other polymers.

Keyword
: Hydrophobic, Self-cleaning, Wettability, Transparent, Contact Angle, SiNPs, Silica Nanopartciles

Figure 1
Numerical Simulation of Cathodic Process on Pure Titanium in a Simulated Body Fluid
Authors: Nakamura Yuma , Miyabe Sayaka , Fujimoto Shinji
Published: December 2020

Metals and alloys have been in use as biomaterials for a long time due to higher strength, superior ductility and toughness compared to other types of biomaterials such as polymer and ceramics. In particular, titanium and its alloys are often used as implant recently due to closer elastic modulus to living bone, compared to other metallic biomaterials, reducing the stress shielding. Titanium and its alloy usually exhibit good corrosion resistance in living body environments, but corrosion failure of titanium implant has been sometimes reported. As cathodic reaction such as oxygen reduction strongly affects corrosion process, cathodic reaction on metallic implants has been extensively examined. In the present work, the distributions and variations of dissolved oxygen concentration and pH on pure titanium in a simulated body environment during oxygen reduction reaction, which is one of main cathodic reactions on implants are examined by numerical simulation.
Effect of Nb and Cu Additions on High Temperature Oxidation Behavior and Mechanical Properties of Al2O3-Forming Austenitic Alloys
Authors: Omori Shota , Utsumi Haruki , Hayashi Shigenari
Published: December 2020

The addition of Cu to austenitic steels was found to be effective for decreasing the critical Al content and promoting protective alumina scale formation from our recent studies. It was also reported that Nb addition to the alloy promotes the formation of alumina. These two elements are also known to improve the mechanical properties of steels by forming fine precipitates of Cu and intermetallics such as Laves and γ” phases, thus combined addition of these elements is expected to improve both the oxidation and mechanical properties of steels, however, there is no systematic study on the effects of the combined addition of these elements on the oxidation resistance and mechanical properties of austenitic heat-resistant alloys. The aim of this study was to investigate the effects of Nb and Cu on the oxidation behavior and mechanical properties of austenitic heat-resistant alloys containing Nb and Cu.

Fe-25Ni-17Cr-(5~8)Al-(0, 0.5, 1)Nb-(0, 3, 5)Cu (in at.%) alloys were prepared by Ar-arc melting pure constituent metals. The ingots were cold-rolled by 90% and heat-treated at 1200ºC for 1 h, followed by aging at 800 ºC or 600 ºC for up to 500 h. Oxidation samples were cut from the cold-rolled plates and polished down to a 3 µm diamond paste. Oxidation tests were performed at 800°C in a box furnace in air for up to 100 h. The alloys were also subjected to a Vickers hardness test at room temperature and tensile tests at room temperature and 600ºC. The tensile test was performed in Ar at a strain rate of 0.005mm/s. Samples were analyzed by SEM, STEM, TEM, EPMA, GD-OES and XRD.

Fig. 1 shows the oxidation kinetics and room temperature hardness of the alloys with/without different Nb and Cu contents. The oxidation kinetics of the alloys with/without different Nb and Cu contents shown in Fig. 1(a) and (b) reveals that the oxidation mass gain of the alloys without Cu decreased significantly by the addition of Nb and it further decreased with increasing Nb content. The oxidation mass gain of the 1Nb doped alloys tended to increase slightly with increasing Cu content. From the STEM-EDS analysis, it was confirmed that the protective alumina scale was formed on the Cu and/or Nb added alloys. An α-alumina was confirmed to develop on the alloys with Nb addition at about 600 ºC during heating, which is much lower temperature than that reported for formation of an α-alumina, suggesting that Nb addition promotes α-alumina formation. Vickers hardness of all alloys at room temperature increased with aging time, however, the maximum hardness was higher for the alloys aged at 600 ºC than 800 ºC. The hardness of the 5Cu alloy was higher than 0Cu alloy, which might be attributed to a formation of very fine Cu precipitates confirmed by TEM observation.

Figure 1
The Thermal-Oxidation Behavior of Pristine and Doped Magnéli Phase Titanium Oxides
Authors: English Joseph , Wilkinson David P.
Published: December 2020

Magnéli phase titanium oxides (Ti
n
O
2n-1
, 4 < n < 10)1 are promising alternatives to carbon-based materials in aqueous electrochemical technologies,2
–5 but their passivation during operation remains an important challenge to address.6
–8 To elucidate the mechanism for their oxidation and to investigate the influence of doping on their oxidation stability, the thermal-oxidation behavior in air of Ti4O7 doped with V, Cr, Fe, and Ga was investigated by thermogravimetric analysis. Both thermal and electrochemical oxidation of Ti4O7 form the electrically-insulating TiO2 in sufficiently oxidizing conditions. V- and Fe-doping improved the thermal stability of Ti4O7 as evidenced by higher onset temperatures in their thermograms. Three-dimensional diffusion reaction models adequately describe the solid-state kinetics of thermal oxidation of Ti4O7 in air as demonstrated by linear model-fitting. Doping shows a mixed influence on these kinetics reducing both the Arrhenius pre-exponential factor and the activation energy. Cr-doping significantly shortens the lifetime of Ti4O7 in ambient conditions as determined by kinetic predictions.

References

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J. R. Smith, F. C. Walsh and R. L. J. Clarke, J. Appl. Electrochem., 28, 1021 (1998).

F. C. Walsh and R. G. A. Wills, Electrochim. Acta, 55, 6342 (2010).

B. Xu, H. Y. Sohn, Y. Mohassab and Y. Lan, RSC Adv., 6, 79706 (2016).

B. P. Chaplin, Acc. Chem. Res., 52, 596 (2019).

W. Kao, P. Patel, P. and S. L. Haberichter, J. Electrochem. Soc., 144, 1907 (1997).

G. Chen, C. C. Waraksa, H. Cho, D. D. Macdonald and T. E. Mallouka, J. Electrochem. Soc., 150, E423 (2003).

D. Bejan, J. D. Malcolm, L. Morrison and N J. Bunce, Electrochim. Acta, 54, 5548 (2009).

Figure 1
Welcome Remarks - C02: High Temperature Corrosion and Materials Chemistry 14
Authors: Gannon Paul
Published: December 2020

Welcome to C02: High Temperature Corrosion and Materials Chemistry 14! Take a moment to listen to welcome remarks from the lead organizer, Paul Gannon.
New Cultural Elements of European Origin in the Dark Ages of Attica
Authors: Panchenko Dmitri
Published: December 2020

The transformation of burial customs in Protogeometric Athens is to be related to the ancient tradition concerning the coming of the Ionians. The newcomers constituted a new elite in Athens and introduced several new institutions. Burial customs of the newcomers, as well as the types of their swords and their political and military institutions point to their European, especially Scandinavian, affiliation.
Corpus of the Roman Finds in the European Barbaricum. Romania 1
Authors: Grumeza Lavinia
Published: December 2020

The goal of this paper is to present the Roman products found in Arad County (West Romania), to analyse the Roman-Dacians connections, and the avenues by which the Roman goods made their way into the Dacian world, west of the Carpathians. Excluding the coins, Italian goods are sporadically found in Dacian sites dating from the 1st century BC to the 1st century AD: some fragmentary bronze and glass vessels, terra sigillata, and various ceramic plates. Most of the imports occur in settlements and hoards, but except for the coins, other types of Roman items were not treasured. The preponderance of the Republican denarii (and imitations) over the imperial ones can be easily distinguished – no matter where they were struck. The conspicuously high quantity of coins could indicate special donations received by the Dacians from the Romans, particularly during the reign of Burebista and Decebalus.
The Contemporary Exercise of Emergency Powers: Reflections on Permanence, Impermanence and Challenging Times
Authors: Ní Aoláin Fionnuala
Published: December 2020

Emergencies are often unforeseen and unexpected phenomena which require immediate action. Emergencies can be political, social, economic, sanitary and ecological in nature. While acknowledging that a range of different kinds of emergencies require governments to respond by law, this contribution is focused on the ways in which the protection of human rights must be ensured in situations when terrorism, violent-extremism and counter-terrorism can create emergency conditions resulting in emergency responses by states. I particularly address the challenges of sanitary and health emergencies occasioned by the Covid-19 pandemic.
Diagnosing Diapycnal Mixing from Passive Tracers
Authors: Ruan Xiaozhou , Ferrari Raffaele
Published: December 2020

Turbulent mixing across density surfaces transforms abyssal ocean waters into lighter waters and is vital to close the deepest branches of the global overturning circulation. Over the last 20 years, mixing rates inferred from in situ microstructure profilers and tracer release experiments (TREs) have provided valuable insights in the connection between small-scale mixing and large-scale ocean circulation. Problematically, estimates based on TREs consistently exceed those from collocated in situ microstructure measurements. These differences have been attributed to a low bias in the microstructure estimates that can miss strong, but rare, mixing events. Here we demonstrate that TRE estimates can suffer from a high bias, because of the approximations generally made to interpret the data. We first derive formulas to estimate mixing from the temporal growth of the second moment of a tracer patch by extending Taylor’s celebrated formula to account for both density stratification and variations in mixing rates. The formulas are validated with tracers released in numerical simulations of turbulent flows and then used to discuss biases in the interpretation of TREs based estimates and how to possibly overcome them.
Διαφοροποίηση της διδασκαλίας και της μάθησης: Δυσκολίες και παρανοήσεις
Authors: Ιωαννίδου-Κουτσελίνη Μαίρη
Published: December 2020

Το άρθρο επισημαίνει και συζητά τις λανθασμένες αντιλήψεις, γνωστές ως παρανοήσεις (misconceptions) (National Research Council, 1997), οι οποίες αναφέρονται είτε απευθείας στην έννοια και τις διαδικασίες της Διαφοροποίησης της Διδασκαλίας και Μάθησης είτε στις θεωρίες περί μάθησης και του ρόλου του εκπαιδευτικού και οι οποίες επηρεάζουν τη θεωρία και εφαρμογή της διαφοροποίησης, σε τάξεις μικτής ετοιμότητας. Βασικός σκοπός είναι να απαντηθεί το επαναλαμβανόμενο ερώτημα των εκπαιδευτικών για το πώς είναι δυνατό να διδάσκει κανείς και να ικανοποιεί την ίδια ώρα τις διαφορετικές ανάγκες διαφορετικών μαθητών. Η ίδια η ερώτηση αναδεικνύει πολλές λανθασμένες αντιλήψεις. Διευκρινίζεται η έννοια και προτείνονται πρακτικές εφαρμογής στην τάξη καθώς και ενδοϋπηρεσιακής επιμόρφωσης των εκπαιδευτικών σε σχολική βάση, μέσα από διαδικασίες Έρευνας Δράσης (π.χ. Koutselini, 2008b, 2010).