bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of an Electronic Skin Wafer for the Minimization of Peristomal Irritant Dermatitis
Authors: McLister Anna , McCreadie Karl , Davis James 
Published: February 2020

An ostomy is created in response to a gastrointestinal injury or disease, such as Ulcerative Colitis, Crohn’s disease and cancer. A stoma is created by a surgical opening in the lower abdomen, which allows for a section of the intestine to be brought to the surface to allow for the excretion of waste products. The resulting effluent is collected through an ostomy pouch that is attached to the abdomen via an adhesive skin wafer (baseplate) as indicated in Figure 1A. In recent years there has been a tremendous effort expended in the design and development of ostomy appliances, which has helped to revolutionize stoma care and management. However, despite the numerous advances, peristomal skin damage remains an issue and arises as a consequence of the gradual erosion of the protective skin wafer. This results in the underlying skin being exposed to the caustic ileostomy fluid (Figure 1B) which subsequently compromises the integrity of the skin barrier and inevitably leads to irritation and ulceration. In the USA alone, it is estimated that one million patients deal with the routine care of an ostomy, and at some stage they are likely to have experienced an incidence of peristomal skin complication (PSC). Although, there have been improvements in the development of materials used within ostomy appliances, there has been little technological innovation in regards to the active prevention of PSCs.
A novel skin wafer containing a printed electrode array has been designed which can permit the monitoring of the skin pH in situ and thereby alert the patient when the baseplate has been compromised (Figure 1B). The system is based on a conductive carbon layer which has been modified with a range of peptide agents to confer pH selectivity. This electrode layer is integrated within a hydrocolloid (carboxymethylcelluose based gel) which provides a protective layer from the effluent debris that would otherwise compromise the operation of the sensor. As the skin becomes compromised, the pH can be expected to increase and at this point the patient can be alerted to the situation and the pouch appliance replaced before the onset of a PSC. The design and construction of the skin wafer is described and its operation in ileostomy fluid is critically assessed.

Figure 1
Durability Study of Intermediate Temperature-Solid Oxide Fuel Cells with Excellent Cathode Materials
Authors: Yang Ja-Yoon , Park Jun-Young 
Published: February 2020

Solid oxide fuel cells (SOFCs) which can directly covert the chemical energy of fuel to electric energy have received as one of alternative energy sources because of their high energy conversion efficiency, fuel flexibility and low emission of pollutant to the environments. However, there are still several technical issues for making commercialization of SOFCs such as limited durability and long start-up time. Hence, recent studies of the SOFCs have focused on improving performance of SOFCs in the intermediate temperature (IT) to achieve technical goals such as high stability, low-cost component materials, easier sealing and quicker start-up time.
In particular, stable long-term performances of SOFCs are one of the essential factors for commercialization of fuel cell systems. However, the sudden unstable situations such as frequent electrical load on-off and high load can often occur during the SOFCs operations, and thus, these unexpected situations can affect the durability of SOFCs systems. Therefore, we need to investigate performance change of SOFCs under various electrical load conditions including the constant current, current on-off cycles and irregular current change. In addition, post-mortem analysis of SOFCs are necessary to find the main degradation mechanisms after various durability tests.
In this work, Ni-cermet anode supported cells are fabricated by the tape-casting method with neodymium doped ceria and double-perovskite structure based cathode materials (NdBa0.5Sr0.5Co1.5Fe0.5O5+δ). The performance of the cells are investigated by I-V measurement and the durability test also conducted by using load trip (0~200 mAcm-2) and load cycle (120~200 mAcm-2) techniques with controlled current condition at 650 oC.
For electrochemical analysis, electrochemical polarization and characterizations are conducted using an electrochemical impedance spectroscopy (EIS) with a Potentiostat/Galvanostat instrument using a frequency range from 1 MHz to 1Hz. The several physicochemical analyses are also investigated using field emission-scanning electron microscopy (FE-SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD).
References

E. D. Wachsman and K. T. Lee, Science
334 (2011) 935-939.

S. B. Adler, Chem. Rev. 104 (2004) 4791-4843.

E. Park, S. Taniguchi, T. Daio, J. T. Chou and K. Sasaki, Solid State Ionics 262 (2014) 421-427.

B. C. H. Steele and A. Heinzel, Nature 414 (2001) 345-352.

S. Omar, E. D. Wachsman and J. C. Nino, Solid State Ionics 177 (2006) 3199-3203.

M. Kahlaoui, S. Chefi, A. Inoubli, A. Madani and C. Chefi, Ceram. Int. 39 (2013) 3873-3879.

Keywords : Solid oxide fuel cells; intermediate-temperature; durability; perovskite.
Predicting the Formation of Electrodeposition Patterns Caused By Interfacial Instabilities
Authors: Wang Chun-Chieh , Ziegler Kirk J , Narayanan Ranga 
Published: February 2020

Electrodeposition is a common process via which metal ions are reduced at a cathode as a thin film. However, the deposited film on the cathode often exhibits a unique interfacial pattern that is dependent on the applied voltage, the concentration, and the distance between electrodes. Although these morphological instabilities have been observed in the past, it still remains difficult to predict the interfacial pattern formed during electrodeposition. These morphological patterns arise in an electrolytic cell because the reduction reaction runs faster than oxidation. Therefore small crests or troughs on the surface of the electrode act as a disturbance that alters the rate and uniformity of metal deposition at these sites, initiating the growth of an interfacial pattern.
We first develop a model that describes the electrodeposition instabilities that lead to these interfacial patterns. Transport and kinetic reactions described by Butler-Volmer equations are used to calculate and predict the growth characteristics of the film. It is found that the patterns of the film are periodic and harmonic waves composed of different wavelengths. While each wavelength corresponds to a specific growth rate, many wavelengths have similar growth rates. Changes to surface tension and ionic diffusion can yield narrower distributions of the wavelengths observed.
A simple Cu-Cu electrodeposition system is then investigated to observe the instabilities. The pattern on the cathode is observed as a function of deposition time in the presence of random disturbances. By image analysis, the wavelength distribution of the interfacial pattern is detected, which is consistent with the developed model. Due to its inherent instability, the harmonic waves of the pattern are not identical every time under the same experiment condition. Nevertheless, the wavelengths observed during deposition are still located within the predicted range.
The results demonstrate that the wavelengths of the pattern are predictable but difficult to control because of inherent disturbances on the surface. Further, the growth of the patterns creates localized flow convection that leads to the formation of dendritic patterns. Now that the model can predict these patterns, the goal will be to find experimental conditions that can either minimize pattern formation or generate a single wavelength.
Reverse Microemulsion Vs Ultrasound-Assisted Synthesis of PtCu/MWCNT Towards Oxygen Reduction Reaction with Possible Application in Fuel Cells
Authors: Rivera-Lugo Yazmin Yorely , Félix-Navarro Rosa María , Reynoso-Soto Edgar Alonso 
Published: February 2020

Over the years, production of energy has been based on fossil fuels, which naturally arose millions of years ago and include carbon, natural gas and oil. During power generation, these materials generate high concentrations of CO2 in the atmosphere that are harmful to the environment. In addition, it is expected that by 2050 the oil and natural gas will be exhausted.1

A good alternative for power generation are fuel cells, which are devices that convert chemical energy into electrical energy, but for continuous production must implement a continuous supply of reagents. These cells have the advantage of generating energy through chemical processes rather than combustion, thus generating clean processes.
In some fuel cells, such as hydrogen/oxygen cell, the limiting reaction is oxygen reduction, so some studies have focused on optimizing this process. In these cells, the following reactions are performed:2

Anodic reaction (oxidation) H2 → 2 H+ + 2 e- E°=0.000 V
Cathodic reaction (reduction) O2 + 4 H+ + 4e- → 4 H2O E°=+1.229 V
____________________________________________
Overall reaction 2 H+ + O2 → 2 H2O E°=+1.229 V
A primary component of fuel cells is the catalyst which is responsible for accelerating the reaction and it’s regenerated at the end. Platinum is the most used noble metal as electrocatalyst in fuel cells because of its high activity and stability, however one of the major challenges is inactivity of platinum caused by carbon monoxide. To overcome this challenge has been proposed Pt alloy with Cu, since it has been reported that Pt alloy to non-noble metals generates higher catalytic activity in the reduction reaction of oxygen compared with platinum alone.3

In this work we compares the catalytic activity in the reduction reaction of oxygen of PtCu/MWCNT synthesized by inverse microemulsion against ultrasound assisted synthesis, which has the advantage of being a green synthesis to be free of solvents and organic surfactants.

References

Cyber quote on: Proyecto de educación ambiental. Virtual page Cambio climático, http://unidades.climantica.org/es/unidades/02/crise-enerxetica-e-cambio-climatico/o-esgotamento-dos-combustibles-fosiles-e-o-cambio-climatico/1, february 3rd of 2015.

Ojani, R; Valiollahi, R.; Raoof, J.B. Energy 2014, 74, 871 – 876.

Maillard, F.; Martin, M.; Gloaguen, F.; Leger, J. M. Electrochim. Acta 2002, 47, 3431 – 3440.

Figure 1
Synthesis and Characterization of Functionalized CdS-QD Polymeric Nanocomposite Film to Mitigate Laser Attacks on Commercial Aircrafts
Authors: Brain Samantha J. , Zaleski Michelle , Hofmann James , Santefort David , Kozminski Joesph , Crowder Charles , Keleher Jason J 
Published: February 2020

In 2015, the Federal Aviation Administration (FAA) has reported over 3,700 cases of lasers penetrating aircraft windshields. These laser attacks typically involve the use of commercially available laser pointers and pose a number of threats to pilots ranging anywhere from visual distraction to flash blindness. They typically occur at aircraft altitudes less than 4,000 feet when the pilots’ visibility is especially critical to successful takeoffs and landings. The laser pointers used in these attacks are manufactured in a variety of different colors including purple (405nm), blue (445nm), green (532nm), and red (650nm), and are available to the public. This work proposed a donor/acceptor functionalized quantum dot (QD) incorporated polymeric nanocomposite film to mitigate the laser intensity via fluorescence resonance energy transfer (FRET). More specifically, CdS core-shell quantum dots (QDs) functionalized with photoactive organic ligands were immobilized on the CdS nanocrystals via a non-covalent self-assembly scheme. This configuration allowed accurate control of the donor-acceptor separation distance and provided a good model system to explore FRET phenomena in polymeric films. Under aqueous conditions, heat was used to control the diameter of the CdS quantum dots. Current results show that in liquid phase, the addition of an organic dye non-covalently linked to the CdS surface showed sufficient fluorescence quenching. Initial results of simulated aircraft green laser testing revealed that there is significant energy dissipation and a noticeable (20 -50 nm) wave-shift upon exposure to nanocomposite films.
(Invited) Silicon Quantum Dots: From Single-Dot Studies to Highly Luminescent Ensembles
Authors: Linnros Jan 
Published: February 2020

The luminescent properties of nanoscale silicon were demonstrated in 1990 triggering the interest in Si nanostructures for optical emission. While the luminescence was quite strong even at room temperature, the micro-second long PL lifetimes revealed an inherited indirect bandgap from bulk Si. The luminescence mechanism was heavily debated whether quantum confinement really played a role or the emission would be due entirely from surface states. Many studies have confirmed the quantum confinement model but it has also been shown that the emission can be widely tuned by changing the surface passivation or by adding different ligands to the shell. The physics of the emission was however obscured by inhomogeneous line broadening due to the large size dispersion of the emitting entities in porous silicon or in matrices containing silicon nanocrystals. This called for single-dot spectroscopy studies as demonstrated for single molecules and later for nanocrystals of direct bandgap semiconductors.
In this talk I will start by reviewing our work on PL emission and spectroscopy of individual Si quantum dots. These were initially fabricated using electron-beam lithography, plasma etching and oxidation resulting in micron spaced Si quantum dots that could be individually distinguished in an optical microscope. More recently we have also looked at more “randomly” spaced Si nanocrystals as well as colloidal nanocrystals dispersed on a wafer. These single-dot studies have revealed many of the phenomena observed for the II-VI nanocrystals such as on/off intermittency (blinking), spectral diffusion and narrow linewidth. Indeed, the linewidth at low temperatures was found to be ~250 µeV, limited by system resolution while the room temperature homogenous linewidth was shown to depend on the surface passivation and ligand shell. Recently, we have also performed absorption measurements of single nanocrystals revealing several distinct absorption levels above the fundamental bandgap that can be compared to theoretical calculations.
Finally, in a collaboration with the group of Prof Veinot at the Univ. of Alberta, we have examined colloidal dispersions of Si nanocrystals fabricated from HSQ (hydrogen silsesquioxane). Recent data show very high quantum yields approaching 70 % for these nanocrystals. Lifetime measurements suggest that near 100 % internal quantum efficiency can be reached paving the way for many applications.
(Invited) Nanophotonic Designs for Luminescent Quantum Dots and Application to Photovoltaics
Authors: Ferry Vivian E. 
Published: February 2020

The combination of photonics with light-emitting materials offers the ability to enhance luminescence efficiency through manipulation of the radiative rates in addition to the transformation of devices utilizing luminescent materials.
The initial portion of this talk will discuss the combination of quantum dots with plasmonic nanostructures for enhanced luminescence efficiency, comparing the effects of controlling the radiative rates with designs to enhance and direct luminescence over large area films.
We will then discuss the design and considerations behind photonic luminescent solar concentrators. Luminescent solar concentrators offer many advantages over traditional concentrator geometries, including the ability to capture diffuse illumination, and the potential for integration with architectural materials. In a standard LSC design, incident sunlight is absorbed by a luminophore embedded within a plastic sheet, re-emitted at longer wavelengths that are trapped by total internal reflection, and eventually concentrated to an edge-mounted solar cell. Although promising, such devices suffer from losses including reabsorption of the emitted light by the luminophore, non-unity quantum yields, and incomplete light guiding to the solar cell.
Recent work has focused on the development of luminescent materials based on colloidal nanocrystals with large Stokes shifts to overcome the reabsorption losses. These colloidal nanocrystals hold other advantages as luminescent materials, as their narrow emission bandwidth enables the use of photonic structures that address other light guiding losses. Such photonic designs must operate over a broad spectral range and range of incident angles. By combining luminescent materials with photonic structures, longer propagation lengths and higher concentration factors can be reached.
One of the key advantages of these luminescent nanocrystals is their tunability. Here we focus particularly on core-shell quantum dot heterostructures. We will show the effects of tuning the luminophore shape on the conversion efficiency, with respect to both the changing optical properties due to quantum confinement effects and the scattering due to the volume of the nanocrystal. Using a wavelength-selective photonic mirror, which is designed to accept blue light and trap the luminescent light, we then explore how the combination of a tunable luminophore and tunable photonic structure can be implemented to improve light guiding efficiency. Finally, we will compare different photonic designs for implementation with these nanocrystals.
In Situ Liquid-Cell Transmission Electron Microscopy Investigation of Nickel Electrodeposition
Authors: Wang Yuxuan , Li Zhe-Fei , Wang Dan , Botte Gerardine G 
Published: February 2020

Nickel electrodes prepared through electrodeposition processes have been demonstrated as promising catalysts for urea electrolysis, towards the applications of urea removal from urea-rich wastewater and hydrogen production.[1-5] The urea electrochemical oxidation process in alkaline media can be described as the equations below:
CO(NH2)2(aq) + 6OH− → N2(g) +5H2O(l) +CO2(g) +6e− (1)
6H2O(l) + 6e−→3H2(g) +6OH−
(aq) (2)
Reaction (1) and (2) happen at the anode and cathode of the urea electrolyzer respectively.[5] The overall reaction is shown below:
CO(NH2)2(aq) +H2O(l)→N2(g) +3H2(g) +CO2(g) (3)
However, there is still lack of knowledge on how the nickel catalysts behave during the electrodeposition and urea electrolysis process.
Recent development of in-situ transmission electron microscopy (TEM) with liquid cell has provided an excellent tool to direct observe material evolution at nanoscale in a liquid environment.[6] With this technique, sample behavior under dynamic operating conditions, such as various electrochemical reactions with the help of incorporated three-electrodes setup, can be imaged in the real time, which could further assist the understanding of the reaction process along with the mechanism behind it.
Within this study, the nickel electrodeposition process has been investigated using in-situ liquid-cell TEM. The experiments were carried out with a state-of-the-art flow cell TEM holder equipped of three electrodes system. The nickel particles were electrodeposited on a thin glassy carbon working electrode during the cyclic voltammetry (CV) scans, as shown in Figure 1. The TEM images were recorded using JEM 2100F field emission TEM. This work revealed the formation process of the nickel particles and made it possible to achieve the precise control of electrode synthesis. It also opened a window for understanding other electrodeposition processes and urea electrolysis with nickel based catalysts.
Figure 1 shows the TEM image of electrodeposited nickel particles on the platinum working electrode of the in situ TEM cell along with the cyclic voltammgraphs (inserted) to obtain these nickel particles.

References

[1] B. K. Boggs, R. L. King, G. G. Botte, Chem. Commun. 2009, 32, 4859-4861
[2] A. N. Rollinson, J. Jones, V. Dupont, M. V. Twigg, Energy Environ. Sci. 2011, 4(4), 1216-1224
[3] D. Wang, W. Yan, S. H. Vijapur, G. G. Botte, J. Power Sources 2012, 217, 498-502
[4] W. Yan, D. Wang, G. G. Botte, Electrochim. Acta 2012, 61, 25-30.
[5] D. Wang, G. G. Botte, ECS Electrochem. Lett. 2014, 3(9), H29-H32
[6] H. Liao, K. Niu, H. Zheng, Chem. Commun., 2013, 49, 11720-11727
Figure 1 TEM image of nickel particles with inserted CV curves for electrodeposition.

Figure 1
Self-Terminated Electrodeposition Reactions for Electrocatalysis
Authors: Moffat Thomas P. , Liu Yihua , Ahn Sang Hyun , Wang Rongyue , Ritzert Nicole L. , Schwarz Kathleen , Gokcen Dincer , Hangarter Carlos , Bertocci Ugo 
Published: February 2020

Development of a sustainable hydrogen economy based on water electrolysis and fuel cells is constrained by the performance, longevity and high cost of Pt group electrocatalysts. Important strategies for improving catalytic reactivity include alloying, forming bimetallic or alloyed surfaces, and engineering substrate–catalyst interactions. At the same time, significant effort is underway to minimize the loading of Pt group metals by examining new synthesis methods and electrode geometries. Of particular interest is atomic layer deposition (ALD) for growing ultrathin films that maximize utilization of rare, expensive metals and facilitate the exploration of bimetallic effects in electrocatalysis.
Recently, an inexpensive “wet form” of ALD based on self-terminated electrodeposition reactions was uncovered that enables controlled formation of ultrathin films of Pt, Ir and iron group metals and alloys thereof. The mechanism of self-terminated deposition reactions will be discussed and the utility of these films as bimetallic electrocatalysts will be demonstrated. For example, monolayer equivalent Pt and Ir films were found to match or exceed the best known specific HER/HOR activity for bulk polycrystalline Pt or Ir electrodes and thereby offer the promise of increasing the scalability of these important precious metals in energy conversion devices.