bluuebunny/crossref_metadata_2025 huggingface dataset:
Cementation Reaction of Lithium Powder Electrodes for Improving the Electrochemical Performances of Lithium-Metal Batteries
Authors: Kolesnikov Aleksei , Zhou Dong , Kolek Martin , Bieker Peter , Winter Martin , Stan Marian Cristian
Published: February 2020

Lithium metal is of particular interest for higher energy density Lithium Metal Batteries (LMBs) for example all-solid-state batteries, lithium/sulfur or lithium/oxygen batteries.1 Furthermore, there are several challenges to overcome, such as lithium dendrite growth, volume changes of the electrodes or low Coulombic efficiency, before reaching commercialization. With respect to these points, the initial morphology of the lithium metal could play an important role in suppressing the formation of lithium dendrites. However, the use of lithium powder is mainly limited to the prelithiation of high capacity electrodes.2

Using a common slurry casting method with polyisobutylene (PIB) as a binder3 allows the preparation of electrodes that preserve the spherical shape of lithium-powder particles. However, these lithium-powder electrodes suffer from poor active material utilization which is caused by the electronic isolation of such particles during lithium electrodissolution. In literature, studies could show an increase in mechanical surface stability after implementation of Li-rich composite alloy films on lithium electrodes.4 This approach (cementation reaction with ZnI2) was adapted to be suitable for lithium powder modification with the goal of the improvement of active lithium loss. The resulted growth of a Li-Zn alloy phase within the bulk lithium-powder electrodes and on their surface was found to improve the electronic contact between the lithium-powder particles. With this method, an increase in active material utilization could be achieved, resulting in enhanced cycling performances of LMBs with lithium powder anodes.

Betz, J.; Bieker, G.; Meister, P.; Placke, T.; Winter, M.; Schmuch, R. Advanced Energy Materials
2018, 1803170.

Holtstiege, F.; Schmuch, R.; Winter, M.; Brunklaus, G.; Placke, T. Power Sources
2018, 378, 522.

Heine, J.; Rodehorst, U.; Qi, X.; Badillo, J. P.; Hartnig, C.; Wietelmann, U.; Winter, M.; Bieker, P. Electrochimica Acta
2014, 138, 288.

Liang, X.; Pang, Q.; Kochetkov, I. R.; Sempere, M. S.; Huang, H.; Sun, X.; Nazar, L. F. Nature Energy
2017, 2, 17119.
Semi-Interpenetrating Networks for All-Solid-State Lithium Metal Batteries
Authors: Homann Gerrit , Cekic-Laskovic Isidora , Winter Martin
Published: February 2020

In the past two decades, exponentially growing markets of mobile consumer electronics and electric vehicles caused an increasing demand towards higher energy and power density in energy storage technologies. Aiming to overcome the intrinsic limitations of state of the art liquid organic carbonate-based electrolytes with regard to higher energy densities and cost efficient cells solid state electrolytes are a promising topic of research. Enabling not only the use of electrolyte layers in the range of a few micrometers and a reduction of needed security features of the cell housing, but also the utilization of lithium metal as anode. Besides the prominent classes of oxidic ceramic and sulfidic glassy electrolytes, the class of lithium ion conducting polymer electrolytes comprises a large variety of different subclasses. The subclass of semi-interpenetrating networks (s-IPNs) defines a combination of at least two polymer networks penetrating each other without a covalent bonding between the different polymer species. Thanks to its excellent interface wetting ability, processability and lithium metal compatibility, polyethylene oxide (PEO) was selected as lithium ion conducting polymer.[1] This combination of different polymer types allows the tailoring of vital physicochemical and electrochemical properties of the resulting s-IPN membranes. Possible benefits of a second interwoven polymer matrix refer to the reduction/suppression of PEO crystallization inside of confinements, thus allowing the utilization of polymer membranes at ambient temperature, an enhanced mechanical stability of thin film membranes compared to single polymer materials and the improved homogeneity of lithium precipitation by a more defined interface structure.[2] Depending on the preparation route of the s-IPN, not only the polymer itself but also the polymer interfaces can be tuned selectively by introduction of, for example, highly hydrophobic substances like siloxanes, which tend to accumulate at the membrane surfaces.[3] The prepared s-IPN membranes in this work were investigated by means of selected thermal, electrochemical and spectroscopy techniques including differential scanning calorimetry, galvanostatic and potentiostatic experiments as well as impedance spectroscopy. This work aims for an economic approach to tailor vital physicochemical properties of s-IPN electrolyte membranes by utilization of PEO as lithium ion conductor and lithium metal as anode material using a single-step solution casting synthesis route towards advanced all-solid-state lithium metal batteries.

References

[1] J. Mindemark, M. J. Lacey, T. Bowden, D. Brandell, Prog. Polym. Sci.
2018, 81, 114–143.

[2] J. R. Nair, M. Destro, F. Bella, G. B. Appetecchi, C. Gerbaldi, J. Power Sources
2016, 306, 258–267.

[3] E. Cznotka, S. Jeschke, P. Vettikuzha, H. D. Wiemhöfer, Solid State Ionics
2015, 274, 55–63.
Structural Optimization and Phase Stability of Cubic Li7La3Zr2O12 for Solid Electrolyte Application
Authors: Tran Ngoc Thanh Thuy , Lin Shih-kang
Published: February 2020

All-solid-state battery is considered as the next-generation batteries due to its high safety and increased energy density, in which the solid electrolyte is one of the key component that determines its performance. The search for stable solid electrolytes with high conductivity is currently an important issue to compete the liquid ones in commercial batteries. The garnet-type structure Li7La3Zr2O12 (LLZO) have attracted great attention, especially the cubic LLZO which is the best conducting Li-oxide garnet reported to date. In this work, the stoichiometric structure of pristine cubic LLZO has been successfully optimized by using the first-principle calculations.This has not been previously reported so far due to the complicated Li disorder. Moreover, the chemical potential diagram is employed to determine the competing phases for phase stability evaluation and is constructed by the thermodynamic conditions of the phase and the constraints imposed by all stable compounds on the Li–La–Zr–O phase diagram. This work is expected to provide a better understanding on the complex cubic LLZO structure as well its phase stability.

Figure 1
Sulfurized-Poly(acrylonitrile) Coated C/S Composite Cathode Materials for Rechargeable Lithium-Sulfur Batteries
Authors: Weret Misganaw Adigo , Hwang Bing-Joe , Jeffrey Kuo Chung-Feng , Su Wei-Nien
Published: February 2020

Lithium-sulfur batteries (Li–S) received growing attention owing to the high theoretical energy density of 2600 Wh kg−1 along with the high theoretical specific capacity of 1675 mAh g-1, low cost, and natural abundance of elemental sulfur. However, dissolution of polysulfides, shuttling effect, and short cycle life are still challenges which limit the practical applications of Li–S batteries. Sulfurized-poly(acrylonitrile) composite cathode materials provide high specific capacity and decipher polysulfide dissolution though active materials loading and rate performance are remaining unsatisfactory. Here, we synthesize a sulfurized-poly(acrylonitrile) coated C/S composite using a dissolution-reprecipitation method followed by the thermal treatment. The dissolution-reprecipitation of SP@PAN boost the surface area of the composite that hold high active sulfur, enhance the composite-electrolyte contact and improve the conductivity of the cathode. Consequently, the prepared sulfurized-poly(acrylonitrile) coated C/S composite cathode materials yield excellent cyclability and high rate capability of 492 mAh g-1 at a high C-rate of 10 C with a high active sulfur loading of 54.5 wt%.
A Closer Theoretical and Experimental Look at Iodine in Li-Air Chemistry
Authors: Jónsson Erlendur , Kerber Rachel Nathaniel , Liu Tao , Kim Gunwoo , Grey Clare P.
Published: February 2020

Increased scientific interest in lithium-air (Li-air) batteries has emerged from recent developments in materials science and technology. Li-air batteries are considered as “state-of-the-art” battery technology due to their theoretical energy density, which is ten times that of traditional lithium-ion.

Recent work [1] showed the effect of using LiI and H2O as additives for a lithium-oxygen battery. Reversible LiOH formation and removal was shown. One intriguing question is why LiOH rather than the typical Li2O2 discharge product forms under these experimental conditions. The work presented here discusses the nature of the complexes formed in the wet organic electrolytes, which is critical for understanding the synergistic effect of water and LiI at fundamental level. Our current work utilises the solvent diglyme/dimethoxyethane [2].

First, electrolytes with various water concentrations were investigated using molecular dynamics (MD), to reveal the corresponding Li+ coordination, water clustering, etc. Density functional theory (DFT) was then used to calculate the cluster models extracted from MD simulations and to benchmark with experimental results (for example, NMR chemical shifts) obtained from various electrolytes.

Secondly, DFT was also used to calculate the standard Gibbs free energy change (∆G) of relevant discharge reactions in both gas phase and as molecular complexes predicted from the MD simulations. These results reveal the local coordination environment of the Li-I pair and how water pushes dimethoxyethane out of the coordination shell, and shed light on how a four-electron oxygen reduction reaction to form LiOH is realized in an ether-based nonaqueous electrolyte via LiI.

Reference
s
:

[1] T. Liu, et al., Science, 350 (2015), 530-533

[2] T. Liu, et al., ACS Catal., 9 (2019), 66-77
Array of Single Nanocavity Electrodes for Lab-on-a-Chip
Authors: Hong Seong Jun , Kim Yang-Rae
Published: February 2020

Electrochemical methods have been frequently employed in lab-on-a-chip systems for biosensing and biomedical analysis of analytes. For this goal, fabrication of electrode is one of important steps because material and structure of electrode have significant effects on performance of electrochemical detection. In these days, various nano-sized electrodes were prepared by several methods because they have some advantages compared to macro/micro-sized electrodes such as enhanced mass transport, improved signal to noise ratio, and minimal iR drop.

In this study, to get higher current and to keep the advantages of nano-sized electrode, the array of a nanocavity electrode with controlled diameter and structure was fabricated by photolithography and focused ion beam. Each electrode in the array is designed to work individually, which indicates that simultaneous and multiplex detection of several biomarkers is enabled for efficient lab-on-a-chip system. First of all, it is necessary to investigate the electrochemical behavior of single nanocavity electrodes. The redox behavior was intensively studied according to scan rates, kinds of redox species, concentrations of redox species, kinds of supporting electrolyte, and concentrations of supporting electrolytes.
(Invited) Redox Polymer-Based Gas Breathing H2-Oxidation Anodes Equipped with Highly Active [Nife] and [Nifese] Hydrogenases for Biofuel Cell Applications
Authors: Ruff Adrian , Szczesny Julian , Markovic Nikola , Conzuelo Felipe , Zacarias Sonia , Plumeré Nicolas , Pereira Ines A. C. , Lubitz Wolfgang , Schuhmann Wolfgang
Published: February 2020

Hydrogen is one of the most promising alternative energy supplies for future technologies to overcome the problems arising from the use of fossil fuels. However, scarce and costly materials, like noble metals, are required as electrocatalysts to build high performance fuel cells in which the energy that is stored in H2 is converted into electricity. An alternative for such catalysts is provided by nature in form of the highly active hydrogenases (H2ases) that catalyze the reversible interconversion of hydrogen with active centers solely based on earth abundant metals (Ni and/or Fe). However, so far, their intrinsic sensitivity towards O2 and high potentials and the low solubility of the gaseous substrate H2 in conventional electrochemical cells hampers the use of H2ases in technological applications.

Based on previous work conducted in our group that describes the protection of these sensitive biocatalysts by incorporation of the enzyme into an O2 reducing viologen modified polymer matrix [1,2] we developed high current density gas breathing redox polymer/H2ase based H2 bioanodes with current densities of up to 8 mW cm-2 that overcome limitations arising from limited H2 mass transport and still show the desired protection of the sensitive biocatalyst in the presence of O2 and at high potentials. [3] Moreover, the immobilization of bienzymatic O2 scavenging systems that are fully decoupled from H2 oxidation on top of the active H2 oxidation layer ensured a complete protection of the sensitive biocatalyst without any losses in current output in the presence of O2. [4] Integration of the bioanodes into H2/air and H2/glucose powered biofuel cells show remarkable open circuit voltages of 1.13 V to 1.15 V, respectively, and power densities of up to 3.6 mW cm-2 at 0.7 V. [3]

[1] N. Plumeré, O. Rüdiger, A. A. Oughli, R. Williams, J. Vivekananthan, S. Pöller, W. Schuhmann, W. Lubitz, Nat. Chem.
2014, 6, 822. [2] A. Ruff, J. Szczesny, S. Zacarias, I. A. C. Pereira, N. Plumeré, W. Schuhmann, ACS Energy Lett.
2017, 2, 964. [3] J. Szczesny, N. Marković, F. Conzuelo, S. Zacarias, I. A. C. Pereira, W. Lubitz, N. Plumeré, W. Schuhmann, A. Ruff, Nat. Commun.
2018, 9, 4715. [4] A. Ruff, J. Szczesny, N. Marković, F. Conzuelo, S. Zacarias, I. A. C. Pereira, W. Lubitz, W. Schuhmann, Nat. Commun. 2018, 9, 3675.
Observation of Direct Electron Transfer from Glucose Dehydrogenase to Single Sheet Graphene Electrode
Authors: Filipiak Marcin Szymon , Vetter Daniel , Thodkar Kishan , Gutierrez-Sanz Oscar , Jönsson-Niedziółka Martin , Tarasov Alexey
Published: February 2020

Continuous glucose monitoring (CGM) is an emerging technology that can provide a more complete picture of the diabetes patient’s glucose levels. Amperometric blood glucose tests typically require redox mediators to facilitate charge transfer from the enzyme to the electrode, that are not ideal in CGM settings because of their potential toxicity or long-term stability issues. Direct electron transfer (DET) would eliminate this need and has therefore attracted substantial interest. However, most DETs studies so far have used glucose oxidase leading to controversial results because the oxygen dependency may be misinterpreted as DET. Here, we overcome this challenge by using an oxygen-insensitive glucose dehydrogenase. The biosensor strongly responded to glucose even without a redox mediator, implying direct electron transfer (Fig. 1 A). Control measurements on different surfaces further confirm that the response is enzyme-specific. To enable direct electron transfer, the enzyme was immobilized on the surface of high-quality single-layer graphene electrodes via short pyrene linkers (<1 nm) (Fig. 1 B). The activity of immobilized enzymes was confirmed by glucose measurements with relatively unexplored redox mediator - nitrosoaniline, and the influence of a most potent interferent in blood, ascorbic acid, was assessed (Fig. 1 C). This is the first demonstration of DET from an oxygen insensitive enzyme to single-layer graphene, highlighting the potential of such devices for applications in CGM.

Figure 1
Long Term Field Testing of Floating Microbial Fuel Cells in Anoxic Wastewater of a Purification Plant
Authors: Pizza Francesca , Gajda Iwona , Greenman John , Ieropoulos Ioannis , Bonelli Paolo , Cristiani Pierangela
Published: February 2020

In the present study, we report different prototypes of floating MFCs that have been tested in anoxic wastewater environments of an Italian wastewater treatment plant, over a period of 3 years. Several configurations of horizontal (flat) and vertical (tubular) MFCs were assembled and tested, using low-cost and light-weight materials, such as plastic lunch boxes, polystyrene or wood to keep the systems afloat and ceramics. Untreated carbon cloth/veil was used for both the anode and cathode electrodes, and felt (flat MFCs) or clay (tubular MFCs) was used as the cation-exchange separator. Flat MFCs generated up to 15 mW/m2 of power, depending on nutrient availability in the water, whereas the cylindrical MFCs generated up to 18 mW/m2. The long-term operation did not affect the electrodes of the tested MFC systems. The cathode was the limiting electrode, sensitive to light, for the flat MFCs smaller than 50x50cm. In addition, a new and simple low-energy remote monitoring system, based on LoRa technology, was used for data transmission over distances of > 500 m. This is a piece of hardware that can potentially be used remotely in the field to create a sensing/monitoring network, as it can be directly powered by the deployed MFCs.

Figure 1
Inhibiting Biocorrosion of Pipeline Steel in the Presence of Zinc Molybdate Nanocrystals within a CO2 Saturated Desulfovibrio Desulfuricans bacterial Culture Under Carbon Source Deprivation
Authors: Eduok Ubong , Szpunar Jerzy
Published: February 2020

Even with limited organic carbon sources in oilfields, the presence of sulphate reducing bacteria (SRB) intensifies microbiologically influenced corrosion (MIC), consequently leading to compromised material integrity. On pipeline steel substrates with active biofilms, Feo is subsequently utilized as an alternative donor by SRBs during energy metabolism. In this work, the survival of Desulfovibrio desulfuricans (ATCC 27774) SRB cells and their impact on the pipeline steel (API 5L X70) corrosion within simulated CO2-saturated oilfield-produced water with different concentrations of organic carbon source have been investigated. Cell counts reduced with the level of carbon source reduction after incubation, but more cells survived at moderate carbon starvation compared to extreme conditions. To combat MIC, we have introduced different concentrations of zinc molybdate (ZnM) crystals against bacterial growth, synthesized from a new chemical route. The rate of MIC reduces more than 80 times in the presence of ZnM crystals under anaerobic conditions, and this has been attributed to the cellular growth inhibitive effect of ZnM. The extent of SRB colonization of steel was monitored within duration of study using confocal laser scanning microscopy after staining with appropriate Live/Dead dyes. Steel biocorrosion mechanism is elucidated by means of electrochemical impedance spectroscopy, potentiodynamic polarization and surface analyses. Adhering corrosion products on steel in the presence of D.
desulfuricans biofilm are predominantly FeO films and FeS/MnS aggregates; this has been confirmed by X-ray photoelectron spectroscopy. Severe anodic steel dissolution is observed on steel within the test culture without ZnM, and this is attributed to SRB-led MIC and CO2 corrosion. Here, the energy needed for cellular survival was harnessed by a combination of Feo oxidation and sulfate reduction even after carbon source starvation. The degree of biocorrosion inhibition increases with ZnM crystal concentration and as more bacterial cells die off within the culture media.
A Whole Cell Bioelectrochemical Sensor for the Monitoring of Benzene in Water
Authors: Espinoza-Tofalos Anna , Formicola Francesca , Cristiani Pierangela , Papacchini Maddalena , Franzetti Andrea
Published: February 2020

Bioelectrochemical Systems (BES) are a novel technology in which microorganisms degrade the organic matter in anaerobic conditions by using an electrode (anode) as final electron acceptor. Therefore, BES can be used as an effective strategy in environments where the absence of suitable electron acceptors limits classic bioremediation. Researches in progress demonstrated the possibility of apply innovative microbial electrochemical technologies for the monitoring and recovering of low concentration of organics, metals and micronutrients from polluted water environments, out of the electric grid. Recently BES have been also studied to stimulate the anaerobic degradation of hydrocarbons [1,2]. Although bioremediation is often inexpensive compared to physical-chemical methods, it typically requires more time and it is currently applied to a limited variety of pollutants. Benzene is a very toxic hydrocarbon and the pollution of this compound in fresh and groundwater causes many health and environmental problems. By monitoring the current produced by a BES, the rate of specific metabolic processes and the substrate concentration can be quantified in real time. The aim of this work is to study the correlation between the current produced in a BES and the concentration of benzene, in the rage of 10–60 mg/L. Tests were performed in single cell membraneless bioelectrochemical systems. The first run consisted in the inoculation of a BES with a refinery waste water in order to colonize the anode with an electroactive benzene-degrading bacterial community. Benzene was periodically supplemented to select a community able to degrade benzene. Current and benzene concentration were monitored, in order to correlate these parameters with the development of an electroactive biofilm. The application of this technology as biosensor for the monitoring of toxic compounds in water presents several advantages: low operational cost, versatility and the possibility to monitor in real time the concentration of pollutants from the environment.

[1] M. Daghio, A. Espinoza Tofalos, B. Leoni, P. Cristiani, M. Papacchini, E. Jalilnejad, G. Bestetti, A. Franzetti. Bioelectrochemical BTEX removal at different voltages: assessment of the degradation and characterization of the microbial communities. Journal of Hazardous Materials, Volume 341, 5 November 2018, Pages 120-127

[2] S. Zhanga, J.Youa, C. Kennes, Z. Cheng, J. Ye, D. Chen, J. Chen, L. Wang. Current advances of VOCs degradation by bioelectrochemical systems: A review. Chemical Engineering Journal, Volume 334, 15 February 2018, Pages 2625-2637
Strategies to Boost MFC Power By Supercapacitive Materials and Components
Authors: Poli Federico , Morigi Matteo , Seri Jacopo , Malaie Keyvan , Mashkour Mehrdad , Soavi Francesca
Published: February 2020

The low cost, the intrinsic robustness, the low environmental impact combined with the potential integration with the current production processes are some of the strength points that are pushing the research on Microbial Fuel Cells (MFCs) since the last thirty years.

Still, to become a technology capable of incisively change the water and energetic landscape critical issues, MFCs needs to be improved for power output and quality.

Here we report about three main strategies to address this challenge: i) the enhancement of the oxygen redox reaction at the cathode in the circum-neutral pH environment of MFCs by PGM-free catalysts based on Manganese and/or Iron oxides prepared by fast autocombustion from nitrates and glycols; ii) the exploitation of the inherent capacitive behaviour of the metal (Fe, Mn) oxides cathodes, iii) the smart integration of MFCs with commercial supercapacitors properly sized and connected in order to match short recharge time and high power output.

Acknowledgments

The research has been carried out under the Italy-South Africa joint Research Programme 2018-2020 Italian Ministers of Foreign Affairs and of the Environment.

References

Malaie, Keyvan, et al. "Simple preparation of carbon–bimetal oxide nanospinels for high-performance bifunctional oxygen electrocatalysts." New Journal of Chemistry 42.24 (2018): 20156-20162.

Francesca Soavi, Keyvan Malaie and Mohammad Reza Ganjal, “Towards low-cost and sustainable supercapacitor electrode processing simultaneous carbon grafting and coating of mixed-valence metal oxides by fast annealing
”, Frontiers, Accepted manuscript
Modelling of Microbiologically Influenced Corrosion (MIC) of Metallic Alloys in Seawater By Electrochemical Impedance Spectroscopy in a Nano-Meter Scale
Authors: Habib Khaled , Al-Muhanna Khalid
Published: February 2020

The main purpose of this study was to model the growth of the marine bio-film, of micro/macro-organisms, on the surface of two metallic alloys in seawater by electrochemical impedance spectroscopy (EIS). The alloys used in this study were; UNS 1020 carbon steel and stainless steel 304. The EIS was used to measure the double layer capacitance (Cdl) of the formed bio-film in seawater on a frequent basis. The total exposure time of the tests was ranged between 90 days to 180 days. The visual inspection of the tested samples showed a bio-film formation on the surface of these samples. The microbiologically influenced (induced) corrosion (MIC) was observed only on the carbon steel. Monitoring the growth of the bio-film formation was accomplished by the EIS during the 90-180 days exposure of the tested samples. A gradual monitoring of the growth of the bio-film formation was achieved by mathematically correlating the obtained double layer capacitance (Cdl) of the bio-film to the thickness of the bio-film formation. The mathematical correlation was derived based on taking into the account parameters such as; the dielectric constant of the formed bio-film, the dielectric constant of the seawater at two temperatures 18oC and 33 oC, the volume fraction of the seawater in the bio-film, the dielectric constant of corrosion products in the bio-film. The advantage of EIS is a non-invasive technique with a sensing (spatial) resolution in a nanometer scale in a comparison to other techniques of monitoring the growth of bio-films on metallic alloys in aqueous solutions.

Key Words: Microbiologically influenced corrosion (MIC); Electrochemical impedance spectroscopy (EIS); Mathematical correlation; Seawater; Double layer capacitance (Cdl).
Microbial Fuel Cell: A Solution for Greenery Waste Treatment
Authors: Joshi Jarina , Maharjan Rocky
Published: February 2020

Microbial fuel cells (MFCs) are devices that can use microbial metabolism to degrade greenary waste from a wide range organic substrates. Alternatively, they produce electricity from microbial metabolism. Agricultural waste is a great problem in the low income country like Nepal. There are different techniques which is used for agriculture waste management. However, these techniques are time consuming and costly. Use of an efficiently designed microbial fuel cell is beneficial for proper management of organic waste of different composition. If there is production of value added products like electricity, will be the additional benefit. A significant amount of reduction in chemical oxygen demand (COD) was observed using MFC when 35% diluted solid greenery waste was used. Further, a maximum open circuit voltage of 222.7 mV was observed when MFC was operated with graphite felt electrode in anode. Vast enhancement in open circuit voltage was found when graphite felt electrode was coated with multiwalled carbon nano tubules/ polyaniline (MWCNT/PANI) was used as anode.

Keyword: Microbial Fuel cell (MFC); cathode; graphite felt; Chemical Oxygen Demand (COD).

References

Rabaey, K., & Verstraete, W. (2005). Microbial fuel cells: Novel biotechnology for energy generation. Trends in Biotechnology,
23(6): 291–298.

Hy Chiu, Ty Pai, MH Liu, CA Chang, FC Lo, TC Chang, HM Lo, CF Chiang, KP Chao, WY Lo, SW Lo and YL Chu (2016). Electricity Production from Municipal Solid Waste using Microbial Fuel Cells. Waste Management and Research. Pp 1-11.
(Invited) Tuning Matrix Solvation for Adjusting the Formal Potential of Redox-Active Centers
Authors: Kopiec Gabriel , Plumeré Nicolas
Published: February 2020

The redox transformation of small molecules such as H2 and CO2 by means of molecular catalysts is of central importance for the conversion of renewable energy. Outer coordination sphere design currently drives the development of such catalysts toward enzyme-like performances. The redox potential of the catalyst is among the key features defining its properties in order to achieve high current densities at low overvoltage. The use of salts from the Hofmeister series in electrolytes provides a new way of adjusting the formal potential of redox systems embedded in polymeric matrices without directly manipulating the chemical structure. Based on viologen moieties serving as model redox active species, we demonstrate that the difference in hydration of chaotropic and kosmotropic anions has an effect on the net solvation of positively charged redox polymers and impact their redox potential. To systematically understand the effect of the counterions on the redox potential shift, electrochemical and spectroscopic analyses of free-diffusing viologens in solution were compared with structure-analog viologen-modified polymer films. Ultimately, the modulation of the solvent induced matrix interactions may be translated as a general lever to control catalyst properties such as electron and proton mobility, substrate binding or product release in analogy to the mode of function of active site of redox enzymes.
(Invited) Dye-Sensitized Metal Oxides for Artificial Photosynthesis
Authors: Gibson Elizabeth Anne
Published: February 2020

Efficient dye-sensitized photocathodes offer new opportunities for converting sunlight into storable energy cheaply and sustainably. We are developing photocathodes based on dye-sensitized metal oxides for light-driven reduction of carbon dioxide or water to higher energy products (solar fuels) using the lessons we have learnt from solar cells. Despite the infancy and complexity of this research area, we have brought about a number of exciting developments which have improved our understanding of the system. We are tackling the main limitations to photocurrent, by improving the quality of the mesoporous electrodes and engineering new photocatalysts specifically for the p-type system, to increase the quantum efficiency of the device. The electron-transfer dynamics are key to the performance and a major challenge is slowing down charge recombination between the photoreduced dye and the oxidised NiO so that chemistry can take place. Highlights from recent work examining charge-transfer at the interface between metal oxides and new supramolecular photocatalysts using transient absorption spectroscopy and time-resolved infrared spectroscopy will be presented alongside the photoelectrochemical characteristics of the devices.

Dye-sensitized photocathodes for H2 evolution, E. A. Gibson, Chemical Society Reviews, 2017, 46, 6194 – 6209.

Photoelectrocatalytic H2 Evolution from Integrated Photocatalysts Adsorbed on NiO, N. Põldme, L. O’Reilly, I. Fletcher, I. Sazanovich, M. Towrie, C. Long, J. G. Vos, M. T. Pryce, E. A. Gibson Chem. Sci., 2019,10, 99-112.

Rapid photoinduced charge injection into covalent polyoxometalate-bodipy conjugates. F. A. Black, A. Jacquart, G. Toupalas, S. Alves, A. Proust, I. P. Clark, E. A. Gibson*, G. Izzet. Chem. Sci., 2018, 9, 5578-5584
Uio-Type Metal-Organic Framework Thin Film with Redox-Active Linkers: Development and Charge Transport Behavior
Authors: Johnson Ben A , Bhunia Asamanjoy , Fei Honghan , Cohen Seth M , Ott Sascha
Published: February 2020

Designing redox-active metal-organic frameworks (MOFs) that can be synthesized as thin films is a key challenge toward their application in electrocatalysis.1 In addition, highly stable MOFs are often electronically insulating in nature, resulting in poor charge transport to redox-catalysts incorporated within the MOF. To overcome these obstacles, we have developed a novel MOF-based thin film platform, which provides electron transport pathways for molecular electrocatalysis.2 The material was rationally designed utilizing the robust Zr-based UiO/PIZOF topology3 and redox-active naphthalene diimide-based linkers (dcphOH-NDI). In addition, hydroxyl groups were included on the dcphOH-NDI linker to facilitate proton transport through the material.

When grown on conducting substrates, this material forms thin films (Zr(dcphOH-NDI)@FTO) that display reversible electrochromic behavior. Importantly, nearly all (97%) of the NDI sites are electrochemically active at applied potential. The method of charge propagation through the film was found to proceed via an electron hopping mechanism that is accompanied by counter ion transport. Finally, the MOF thin films were found to function efficiently in aqueous solutions, adding to their potential usefulness in electrocatalytic applications.

The fabrication of a UiO/PIZOF-type MOF thin film with linkers having a well-defined electrochemical response, confers unprecedented versatility to utilize postsynthetic methods to introduce catalytic units into a robust and widely studied framework that is now redox-active. In the future, this will allow for the roles of charge propagation and catalysis to be carried out by separate linkers within the MOF film, enabling the individual optimization of each process.

Downes, C. A.; Marinescu, S. C. ChemSusChem, 10, 4374−4392 (2017).

Johnson, B. A.; Bhunia, A.; Fei, H.; Cohen, S. M.; Ott, S. J. Am. Chem. Soc., 140, 2985−2994 (2018).

Cavka, J. H.; Jakobsen, S.; Olsbye, U.; Guillou, N.; Lamberti, C.; Bordiga, S.; Lillerud, K. P. J. Am. Chem. Soc., 130, 13850−13851 (2008); Schaate, A.; Roy, P.; Preuße, T.; Lohmeier, S. J.; Godt, A.; Behrens, P. Chem. - Eur. J., 17, 9320−9325 (2011).

Figure 1
Hierarchical Structure Including Nanoscale Passages By Using Wet-Etching of Nickel Thin Films in Lamellae Layers for Bio-Sensors Applications
Authors: Kim Jeong Hwan , Lee Seung-Hun , Kim Kwanoh , Yoon Jae Sung , Yoo Yeong-Eun
Published: February 2020

In recent years, research for surface hierarchical structures for chemical sensor and bio-sensor devices applications has been highlighted owing to their relatively large ratio of surface-area compared to the volume. Especially, the hierarchical micro-nanostructures (organization of the nanostructure within the microstructure) including nanoscale passages have been intensively studied, because nanoscale passages are necessary for single-molecule DNA sequencing. In order to realize a hierarchical micro-nanostructure, the fabrication process for micro- and nano-scale structures should be applied together, controlling each pattern size precisely. Therefore, the properties of lateral Ni film etching by TFB etchant at room temperature were investigated by using samples with patterned lamellae layers consist of Ni, Al2O3, and SiO2 for fabricating hierarchical structures for the fabrication of hierarchical structure including nanoscale passages. Lateral etching length was increased with increasing etching time, despite of the difficult passage through nanoscale passage in lamellae layers. However, higher etching rate (2.1 nm/s) was observed in lower Ni film, which has contact with SiO2 and Al2O3 layers, compared to that (1.6 nm/s) of upper Ni film, which has contact with only Al2O3, due to stronger wetting property of SiO2, inducing easier penetration of etchant into nanoscale passage between surrounding layers. Moreover, the influence of Ni film thickness on lateral etching characteristics was also investigated. In this presentation, the fabrication process based on lateral Ni film etching in lamellae layers by liquid etchant at room temperature will be presented systematically for bio-sensor applications.
Experimental and Analytical Study on the Vibration Performance of U-Shaped Steel-Concrete Composite Hollow Waffle Slab
Authors: Zhang Xi , Wang Qiming , Wang Yousan , Li Qing
Published: February 2020

The large-span floor system being lightweight with low frequency and low damping is prone to suffer severe vibration under human excitations. In this research, the vibration performance of an innovative large-span U-shaped steel-concrete composite hollow waffle (CHW) slab was studied based on field testing and theoretical analysis. First, the modal properties of CHW slab including mode shapes, frequencies, and damping ratio were captured by on-site tests and validated by the finite element method, indicating the CHW slab is a low-frequency floor system with a low damping ratio. Second, the vibration responses of CHW slab under heel-drop and jumping excitations were studied considering the impacts of spatial position, tester number, and activity types. Third, the CHW slab shows excellent vibration serviceability proved by the frequency, accelerations, and human perceptions threshold with the current codes. Meanwhile, the paper gives appropriate threshold values for the CHW slab under impulsive excitation. Finally, the natural frequency formula for the CHW slab derived by the Rayleigh–Ritz energy method agrees well with the measurements.
High Frequency Modal Testing of the Multiblade Packets Using a Noncontact Measurement and Excitation System
Authors: Liu C. H. , Zang C. , Li F. , Petrov E. P.
Published: February 2020

High cycle failure of blades and vanes caused by the vibration is one of the major causes reducing the lifetime of turbomachines. For multiblade packets, the failure may occur at vibrations with high frequencies that can reach up to tens of kHz. The experimental modal testing of blades is crucial for the validation of numerical models and for the optimization of turbomachine design. In this paper, the test rig and procedure for measurements of dynamic characteristics of lightweight multiblade packets in wide and high frequency ranges are developed. The measurements are based on a noncontact excitation and noncontact measurement method, which allows the determination of the modal characteristics of the packets with high accuracy in wide frequency ranges. The responses of the multiblade packets are measured using a Scanning Laser Doppler Vibrometry (SLDV), while vibrations are excited by the acoustic excitation technique. Modal tests of the blade packet comprising 18 vane blades connected by shrouds are performed. The measurements are performed within the high frequency range of 0–30 kHz, and the natural frequencies and mode shapes are obtained for first 97 modes. To capture the complex high frequency blade mode shapes, each blade in the packet is scanned over 25 reference points uniformly distributed over the blade concave surface. In order to obtain the high frequency resolution, the frequency range used for the measurements is split into several frequency intervals accordingly to the number of spectral lines available in the used data acquisition system, and for each such interval, the test is performed separately. The finite model of the packet is created, and the numerical modal analysis is performed to compare the calculated natural frequencies and mode shapes with the experimental measurements. The comparison shows the satisfactory with those from finite element analysis. It illustrates the measurement method described in this work is effective and reliable.
Heme Oxygenase-1-Mediated Autophagy Protects against Oxidative Damage in Rat Nucleus Pulposus-Derived Mesenchymal Stem Cells
Authors: Chen Sheng , Liu Sheng , Zhao Lei , Lin Hui , Ma Kaige , Shao Zengwu
Published: February 2020

Although endogenous nucleus pulposus-derived mesenchymal stem cell- (NPMSC-) based regenerative medicine has provided promising repair strategy for intervertebral disc (IVD) degeneration, the hostile microenvironments in IVD, including oxidative stress, can negatively affect the survival and function of the NPMSCs and severely hinder the endogenous repair process. Therefore, it is of great importance to reveal the mechanisms of the endogenous repair failure caused by the adverse microenvironments in IVD. The aim of this study was to investigate the effect of oxidative stress on the rat NPMSCs and its underlying mechanism. Our results demonstrated that oxidative stress inhibited cell viability, induced apoptosis, and increased the production of reactive oxygen species (ROS) in NPMSCs. In addition, the results showed that the expression level of heme oxygenase-1 (HO-1) increased at an early stage but decreased at a late stage when NPMSCs were exposed to oxidative stress, and the oxidative damages of NPMSCs could be partially reversed by promoting the expression of HO-1. Further mechanistic analysis indicated that the protective effect of HO-1 against oxidative damage in NPMSCs was mediated by the activation of autophagy. Taken together, our study revealed that oxidative stress could inhibit cell viability, induce apoptosis, and increase ROS production in NPMSCs, and HO-1-mediated autophagy might act as a protective response to the oxidative damage. These findings might enhance our understanding on the mechanism of the endogenous repair failure during IVD degeneration and provide novel research direction for the endogenous repair of IVD degeneration.
Alfabetização semiótica com os códigos informático-digitais da internet
Authors: Machado Irene De Araujo , Ramos Daniela Osvald
Published: February 2020

Neste artigo, abordamos as mudanças sociotécnicas na contemporaneidade a partir de uma abordagem histórica advinda da introdução da internet na cultura. Posteriormente, investigamos a importância do conhecimento dos códigos informático- -digitais neste contexto. Desenvolvemos a hipótese de que é necessário enfrentar a complexidade do entendimento da infraestrutura técnica da rede para que possamos formar cidadãos, e não usuários que consomem toda sorte de códigos a partir de dinâmicas complexas e constantes de codificação e recodificação, sem a competência semiótica adequada para a interpretação crítica a partir da autorreferencialidade que a linguagem nos impõe neste novo quadro histórico. Concluímos que é necessário um projeto de alfabetização que contemple o entendimento do uso dos códigos na comunicação.
A educação de hoje rumo à educação planetária de amanhã
Authors: Cury Lucilene , Consani Marciel
Published: February 2020

Este artigo propõe o início de uma discussão ampla e aberta sobre as questões que afetam a educação hoje por conta dos impactos das mídias digitais num contexto de permanente conexão com o processo de ensino-aprendizagem. A premissa básica é que as demandas e os desafios da educação a distância (EaD) são, em princípio, os mesmos que afetam a educação como um todo, ambas profundamente impactadas pelo paradigma da complexidade em dimensão planetária – conceitos iluminadores abordados na obra de Edgar Morin. Ao final desta série de reflexões, almeja-se pontuar a necessidade de um olhar que transcenda as questões puramente tecnológicas e operacionais, ao mesmo tempo que reafirme a importância e a pertinência da abordagem educomunicativa.
Multi-robot formation control based on high-order bilateral consensus
Authors: Liu Dejian , Zong Chengguo , Wang Detang , Zhao Wenbin , Wang Yuehua , Lu Wei
Published: February 2020

A high-order bilateral consensus robot formation control protocol for multi-agent systems is proposed in this paper. Considering the relationship between the state of the information exchange topology and derivatives, a third-order bilateral consistency protocol is presented and is extended it to a higher order bilateral consensus protocol. First, sufficient conditions for the third-order multi-agent system are given to achieve the bilateral consensus control protocol, and the system’s asymptotical stability is also achieved by adjusting the feedback system gain parameters. Then, by further studying the cohesive relationship between each state variable of the third-order protocol and the gauge transformation, the sufficient conditions of the higher order system are also provided. Finally, by applying the third-order control protocol to the control of multi-robot formation, the general control scheme of robot formation is given and the control of robot formation is successfully achieved.
Implementation of the GB Plant Health and Biosecurity Strategy 2014–2019 with foresight on a new strategy for 2020
Authors: Spence Nicola
Published: February 2020

Plants have an essential role in addressing the great social and environmental challenges of our time. However, the risk from invasive plant pests and pathogens is also significant and constantly growing as a result of increasing globalisation and environmental change. The UK’s plant health regime aims to manage that risk to protect the enormous value of plants and trees; from the value of crops and forestry products to ecosystem services and societal benefits. The implementation of the Great Britain Plant Health and Biosecurity Strategy 2014–2019 is described, including the risk-based approach to protecting the plants and trees, and the approaches being taken to manage different kinds of risks, including import controls, management of threats once established, preparedness, utilising citizen science and awareness raising. Looking ahead, there is foresight on a new strategy for 2020 including building a world-class biosecurity regime, which delivers a step change in plant health protections, allows our plant-based industries to thrive and acknowledges the value that healthy plants contribute to society and the environment. International Year of Plant Health 2020 provides a unique opportunity to raise the profile of plant health globally.
Book review: Bidyut Mohanty and Victor Faessel (Eds.), Our Money Our Lives: Microcredit and Women’s Empowerment in Cross Cultural Perspective
Authors: Nagla Madhu
Published: February 2020

Bidyut Mohanty and Victor Faessel (Eds.), Our Money Our Lives: Microcredit and Women’s Empowerment in Cross Cultural Perspective. Delhi: Aakar Books, 2018, 279 pp., ₹795 (hardback). ISBN: 978-93-5002-555-0.
New methods for mapping media concentration: network analysis of joint ventures among firms
Authors: Birkinbine Benjamin J , Gómez Rodrigo
Published: February 2020

Measures of media concentration typically rely on two primary indices: CR4 and HHI. These indices are based on the market share of the top firms as well as the share of total revenues for top firms. These indices only serve as an adequate representation of media concentration sectors if one assumes that the top firms are competitors. However, these measures do not adequately capture the degree to which top firms work together through joint ventures or other shared interests. By using network analysis, this article illustrates the joint ventures that exist among the five largest media firms (Comcast, the Walt Disney Company, National Amusements, AT&T/WarnerMedia, and Fox/News Corporation). We argue that this type of analysis can supplement existing measures of media concentration and may also be useful for policy debates, particularly in reviews of proposed mergers.
The pornographic state: the changing nature of state regulation in addressing illegal and harmful online content
Authors: Keen Caroline , Kramer Ronald , France Alan
Published: February 2020

This article explores the failure of democratic nation-states to regulate corporate Internet intermediaries who essentially provide access to websites containing illegal and legal pornographic content. Existing literature credits this apparent diminishing regulatory role of states to neoliberalism. Drawing on Wacquant’s theory of ‘neoliberal statecrafting’ can explain the paucity of state media regulation while also accounting for when states do engage in alternative forms of regulation. Through a thematic analysis of key documents, media and interviews with ‘elite’ stakeholders in Australia and the United Kingdom, this research shows that private actors are generally exempt from state regulation, while individuals are simultaneously subject to punitive mechanisms for problematic and illegal uses of the Internet.