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Electrolyte-gated transistors (EGTs) represent an interesting alternative to conventional dielectric-gating to reduce the required high supply voltage for printed electronic applications. Here, a type of ink-jet printable ion-gel is introduced and optimized to fabricate a chemically crosslinked ion-gel by self-assembled gelation, without additional crosslinking processes, e.g., UV-curing. For the self-assembled gelation, poly(vinyl alcohol) and poly(ethylene-alt-maleic anhydride) are used as the polymer backbone and chemical crosslinker, respectively, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM][OTf]) is utilized as an ionic species to ensure ionic conductivity. The as-synthesized ion-gel exhibits an ionic conductivity of ≈5 mS cm−1 and an effective capacitance of 5.4 µF cm−2 at 1 Hz. The ion-gel is successfully employed in EGTs with an indium oxide (In2O3) channel, which shows on/off-ratios of up to 1.3 × 106 and a subthreshold swing of 80.62 mV dec−1.
The Future of FDI: Achieving the Sustainable Development Goals 2030 through Impact Investment
(2019)
Publicized as a global call for action in 2015, the United Nations General Assembly passed a resolution on the Sustainable Development Goals 2030 (SDGs). Before issuing the SDGs in 2015, the United Nations Conference on Trade and Development (UNCTAD) has already identified in 2014, as part of their World Investment Report, that especially developing countries are facing an estimated USD 2.5 trillion funding gap annually in the efforts to achieve the SDGs. Yet, the investment opportunities and challenges for investors, when contributing to the closure of this funding gap while benefiting from its economic potential have not been widely discussed. Despite that Foreign Direct Investments (FDI) are a key driver to sustainable economic growth and prosperity of a nation, policies and a holistic framework linking the 2030 Agenda to actionable investment opportunities for private investors are missing. Furthermore, a global platform capturing, channeling and promoting investment projects aiming to achieve the SDGs through impact investment has not been established. Utilizing global financial resources more effectively while developing new approaches and tools to promote impact investments, which demonstrate the benefits for investors to tap into the funding gap of the 2030 Agenda, will have the potential to significantly shape and influence the future of FDI.
The Humboldt Portal has been designed and implemented as part of an ongoing research project to develop an information system on the Internet to share the documents and rare books of Alexander von Humboldt, a 19th century German scientist and explorer, who viewed the natural world holistically and described the harmony of nature among the diversity of the physical world. Even after more than two centuries he is admired for his ability to see the natural world and human nature in the context of a complex network of relationships. The design and implementation of the Humboldt Portal are also oriented to support further research on Humboldt’s intellectual perspective.
Although all of Humboldt's works can be found on the internet as digitized documents, the complexity and internal inter-connectivity of his vision of nature cannot be adequately represented only by digitized papers or scanned documents in digital libraries.
As a consequence a specific portal of the Humboldt's documents was developed, which extends the standards of digital libraries and offers a technical approach for the adequate presentation of highly interconnected data.
Due to the continuous scientific and literary research, new insights and requirements for the digital presentation of Humboldt documents are constantly emerging, so that this article only provides a summary of the concepts realized at now. Consequently, the design and implementation of the Humboldt Portal is both: a consequence of a continuing research project and oriented to support more research on Humboldt´s intellectual holistic perspective, which was an anticipation to the System Approach of the last Century.
In den letzten Jahren sind verstärkt große Batteriespeichersysteme in der Mittel- und Hochspannungsebene in Deutschland installiert worden. Neben dem Einsatz für lokale Anwendungszwecke wie Eigenverbrauchsmaximierung oder Lastspitzenkappung sind seit 2016 etwa 250 MW aus Batteriespeichern für die Teilnahme am Markt für Primärregelleistung (PRL) präqualifiziert worden. Damit können bereits 40 % des aktuellen Bedarfs der deutschen Übertragungsnetzbetreiber (ÜNB) gedeckt werden. Für einen zuverlässigen Betrieb von Batteriespeichern sind intelligente Betriebsstrategien erforderlich, die im Rahmen dieser Analyse vorgestellt werden.
Economic growth and ecological problems motivate industries to apply eco-friendly technologies and equipment. However, environmental impact, followed by energy and material consumption still remain the main negative implications of the technological progress in process engineering. Based on extensive patent analysis, this paper assigns more than 250 identified eco-innovation problems and requirements to 14 general eco-categories with energy consumption and losses, air pollution, and acidification as top issues. It defines primary eco-engineering contradictions, in case eco-problems appear as negative side effects of the new technologies, and secondary eco-engineering contradictions, if eco-friendly solutions have new environmental drawbacks. The study conceptualizes a correlation matrix between the eco-requirements for prediction of typical eco-contradictions on example of processes involving solids handling. Finally, it summarizes major eco-innovation approaches including Process Intensification in process engineering, and chronologically reviews 66 papers on eco-innovation adapting TRIZ methodology. Based on analysis of 100 eco-patents, 58 process intensification technologies, and literature, the study identifies 20 universal TRIZ inventive principles and sub-principles that have a higher value for environmental innovation.
Tryptamines can occur naturally in plants, mushrooms, microbes, and amphibians. Synthetic tryptamines are sold as new psychoactive substances (NPS) because of their hallucinogenic effects. When it comes to NPS, metabolism studies are of crucial importance, due to the lack of pharmacological and toxicological data. Different approaches can be taken to study in vitro and in vivo metabolism of xenobiotica. The zygomycete fungus Cunninghamella elegans (C. elegans) can be used as a microbial model for the study of drug metabolism. The current study investigated the biotransformation of four naturally occurring and synthetic tryptamines [N,N‐Dimethyltryptamine (DMT), 4‐hydroxy‐N‐methyl‐N‐ethyltryptamine (4‐HO‐MET), N,N‐di allyl‐5‐methoxy tryptamine (5‐MeO‐DALT) and 5‐methoxy‐N‐methyl‐N‐isoporpoyltryptamine (5‐MeO‐MiPT)] in C. elegans after incubation for 72 hours. Metabolites were identified using liquid chromatography–high resolution–tandem mass spectrometry (LC–HR–MS/MS) with a quadrupole time‐of‐flight (QqTOF) instrument. Results were compared to already published data on these substances. C. elegans was capable of producing all major biotransformation steps: hydroxylation, N‐oxide formation, carboxylation, deamination, and demethylation. On average 63% of phase I metabolites found in the literature could also be detected in C. elegans. Additionally, metabolites specific for C. elegans were identified. Therefore, C. elegans is a suitable complementary model to other in vitro or in vivo methods to study the metabolism of naturally occurring or synthetic tryptamines.
In numerical calculations, guided acoustic waves, localized in two spatial dimensions, have been shown to exist and their properties have been investigated in three different geometries, (i) a half-space consisting of two elastic media with a planar interface inclined to the common surface, (ii) a wedge made of two elastic media with a planar interface, and (iii) the free edge of an elastic layer between two quarter-spaces or two wedge-shaped pieces of a material with elastic properties and density differing from those of the intermediate layer.
For the special case of Poisson media forming systems (i) and (ii), the existence ranges of these 1D guided waves in parameter space have been determined and found to strongly depend on the inclination angle between surface and interface in case (i) and the wedge angle in case (ii). In a system of type (ii) made of two materials with strong acoustic mismatch and in systems of type (iii), leaky waves have been found with a high degree of spatial localization of the associated displacements, although the two materials constituting these structures are isotropic.
Both the fully guided and the leaky waves analyzed in this work could find applications in non-destructive evaluation of composite structures and should be accounted for in geophysical prospecting, for example.
A critical comparison is presented of the two computational approaches employed, namely a semi-analytical finite element scheme and a method based on an expansion of the displacement field in a double series of special functions.
Modeling and simulation play a key role in analyzing the complex electrochemical behavior of lithium-ion batteries. We present the development of a thermodynamic and kinetic modeling framework for intercalation electrochemistry within the open-source software Cantera. Instead of using equilibrium potentials and single-step Butler-Volmer kinetics, Cantera is based on molar thermodynamic data and mass-action kinetics, providing a physically-based and flexible means for complex reaction pathways. Herein, we introduce a new thermodynamic class for intercalation materials into the open-source software. We discuss the derivation of molar thermodynamic data from experimental half-cell potentials, and provide practical guidelines. We then demonstrate the new class using a single-particle model of a lithium cobalt oxide/graphite lithium-ion cell, implemented in MATLAB. With the present extensions, Cantera provides a platform for the lithium-ion battery modeling community both for consistent thermodynamic and kinetic models and for exchanging the required thermodynamic and kinetic parameters. We provide the full MATLAB code and parameter files as supplementary material to this article.
This article presents the development, parameterization, and experimental validation of a pseudo-three-dimensional (P3D) multiphysics model of a 350 mAh high-power lithium-ion pouch cell with graphite anode and lithium cobalt oxide/lithium nickel cobalt aluminum oxide (LCO/NCA) blend cathode. The model describes transport processes on three different scales: Heat transport on the macroscopic scale (cell), mass and charge transport on the mesoscopic scale (electrode pair), and mass transport on the microscopic scale (active material particles). A generalized description of electrochemistry in blend electrodes is developed, using the open-source software Cantera for calculating species source terms. Very good agreement of model predictions with galvanostatic charge/discharge measurements, electrochemical impedance spectroscopy, and surface temperature measurements is observed over a wide range of operating conditions (0.05C to 10C charge and discharge, 5°C to 35°C). The behavior of internal states (concentrations, potentials, temperatures) is discussed. The blend materials show a complex behavior with both intra-particle and inter-particle non-equilibria during cycling.
Oxidation of the nickel electrode is a severe aging mechanism of solid oxide fuel cells (SOFC) and solid oxide electrolyzer cells (SOEC). This work presents a modeling study of safe operating conditions with respect to nickel oxide formation. Microkinetic reaction mechanisms for thermochemical and electrochemical nickel oxidation are integrated into a 2D multiphase model of an anode‐supported solid oxide cell. Local oxidation propensity can be separated into four regimes. Simulations show that the thermochemical pathway generally dominates the electrochemical pathway. As a consequence, as long as fuel utilization is low, cell operation considerably below electrochemical oxidation limit of 0.704 V is possible without the risk of reoxidation.
In this article the high-temperature behavior of a cylindrical lithium iron phosphate/graphite lithium-ion cell is investigated numerically and experimentally by means of differential scanning calorimetry (DSC), accelerating rate calorimetry (ARC), and external short circuit test (ESC). For the simulations a multi-physics multi-scale (1D+1D+1D) model is used. Assuming a two-step electro-/thermochemical SEI formation mechanism, the model is able to qualitatively reproduce experimental data at temperatures up to approx. 200 °C. Model assumptions and parameters could be evaluated via comparison to experimental results, where the three types of experiments (DSC, ARC, ESC) show complementary sensitivities towards model parameters. The results underline that elevated-temperature experiments can be used to identify parameters of the multi-physics model, which then can be used to understand and interpret high-temperature behavior. The resulting model is able to describe nominal charge/discharge operation behavior, long-term calendaric aging behavior, and short-term high-temperature behavior during extreme events, demonstrating the descriptive and predictive capabilities of physicochemical models.
A physical unclonable function (PUF) is a hardware circuit that produces a random sequence based on its manufacturing-induced intrinsic characteristics. In the past decade, silicon-based PUFs have been extensively studied as a security primitive for identification and authentication. The emerging field of printed electronics (PE) enables novel application fields in the scope of the Internet of Things (IoT) and smart sensors. In this paper, we design and evaluate a printed differential circuit PUF (DiffC-PUF). The simulation data are verified by Monte Carlo analysis. Our design is highly scalable while consisting of a low number of printed transistors. Furthermore, we investigate the best operating point by varying the PUF challenge configuration and analyzing the PUF security metrics in order to achieve high robustness. At the best operating point, the results show areliability of 98.37% and a uniqueness of 50.02%, respectively. This analysis also provides useful and comprehensive insights into the design of hybrid or fully printed PUF circuits. In addition, the proposed printed DiffC-PUF core has been fabricated with electrolyte-gated field-effect transistor technology to verify our design in hardware.
We present a planar chromatographic separation method for the compounds caffeine, artemisinin, and equol, separated on high-performance thin-layer chromatography (HPTLC) silica gel plates. As solvents for separation, methyl t-butyl ether and cyclohexane (1:1, V/V) have been used for equol, cyclohexane and ethyl acetate (7:3, V/V) for artemisinin, and ethyl acetate and acetone (7:3, V/V) for caffeine. After separation, the plate was scanned with a very specific time of flight-direct analysis in real time-mass spectrometry (TOF-DART-MS) system using the (M + 1)+ signals of equol, artemisinin, and caffeine. The (M + 1) peak of artemisinin at 283.13 m/z is clearly detectable, which is the proof that DART-MS is applicable for the quantitative determination of rather instable molecules. The planar set-up of DART source, HPTLC plate and detector inlet in a line showed higher sensitivities compared to desorption at an angle. The optimal detector voltage increases with the molar mass of the analyte, thus an individual determination of optimal detector voltage setting for the different analyte is recommended to achieve the best possible measurement conditions. In conclusion, DART-MS detection in combination with an HPTLC separation allows very specific quantification of all three compounds.
Open markets, international trade and foreign direct investments are a source of prosperity in challenging times. This Special Section looks at developed economies and emerging markets, also taking into account the role of trade for impactful capacity-building in least developed countries (LDCs). Specific emphasis is placed on financing economic development and trade, analysing what roles trade and development finance should play in the quest for an efficient mobilisation of private capital for growth, trade and development.
Thermisch angetriebene (Adsorptions-)Kältemaschinen können mit einem verhältnismäßig geringen elektrischen Energieaufwand bzw. mit einer hohen elektrischen Leistungszahl Kälte bereitstel-len. Wird die zum Antrieb erforderliche Wärme aus industrieller Abwärme bereitgestellt, ist diese Kältebereitstellung energetisch effizienter als die Kältebereitstellung über eine Kompressionskäl-temaschine. Wird die Wärme jedoch in Kraft-Wärme-Kopplung bereitgestellt, ist die primärenergetische Bewertung sowohl von mehreren Teilwirkungsgraden als auch den Primärenergiefaktoren für den eingesetzten Brennstoff und die erzeugte bzw. bezogene elektrische Energie abhängig. Eine umfangreiche Messkampagne im Sommer 2018 liefert unter realitätsnahen Randbedingungen in einer Labor umgebung detaillierte Energiekennzahlen für einen typischen Tagesgang des Kältebedarfs. Damit gelingt es, Teilenergiekennwerte für die Planungspraxis abzuleiten und das Gesamtsystem energetisch mit einer konventionellen Kompressionskältemaschine zu vergleichen.
Printed electronics can benefit from the deployment of electrolytesas gate insulators,which enables a high gate capacitance per unit area (1–10 μFcm−2) due to the formation of electrical double layers (EDLs). Consequently, electrolyte-gated field-effect transistors (EGFETs) attain high-charge carrier densities already in the subvoltage regime, allowing for low-voltage operation of circuits and systems. This article presents a systematic study of lumped terminal capacitances of printed electrolyte-gated transistors under various dc bias conditions. We perform voltage-dependent impedancemeasurements and separate extrinsic components from the lumped terminal capacitance.
The proposed Meyer-like capacitance model, which also accounts for the nonquasi-static (NQS) effect, agrees well with experimental data. Finally, to verify the model, we implement it in Verilog-A and simulate the transient response of an inverter and a ring oscillator circuit. Simulation results are in good agreement with the measurement data of fabricated devices.
Printed systems spark immense interest in industry, and for several parts such as solar cells or radio frequency identification antennas, printed products are already available on the market. This has led to intense research; however, printed field-effect transistors (FETs) and logics derived thereof still have not been sufficiently developed to be adapted by industry. Among others, one of the reasons for this is the lack of control of the threshold voltage during production. In this work, we show an approach to adjust the threshold voltage (Vth) in printed electrolyte-gated FETs (EGFETs) with high accuracy by doping indium-oxide semiconducting channels with chromium. Despite high doping concentrations achieved by a wet chemical process during precursor ink preparation, good on/off-ratios of more than five orders of magnitude could be demonstrated. The synthesis process is simple, inexpensive, and easily scalable and leads to depletion-mode EGFETs, which are fully functional at operation potentials below 2 V and allows us to increase Vth by approximately 0.5 V.
Development of Fully Printed Oxide Field-Effect Transistors using Graphene Passive Structures
(2019)
During the past decade to the present time, the topic of printed electronics has gained a lot of attention for their potential use in a number of practical applications, including biosensors, photovoltaic devices, RFIDs, flexible displays, large-area circuits, and so on. To fully realize printed electronic components and devices, effective techniques for the printing of passive structures and electrically and chemically compatible materials in the printed devices need to be developed first. The opportunity of using electrically conducting graphene inks will enable the integration of passive structures into active devices, as for example, printed electrolyte-gated transistors (EGTs). Accordingly, in this study, we present the parametric results obtained on fully printed electrolyte-gated transistors having graphene as the passive electrodes, an inorganic oxide semiconductor as the active channel, and a composite solid polymer electrolyte (CSPE) as the gate insulating material. This configuration offers high chemical and electrical stability while at the same time allowing EGT operation at low potentials, implying the distinct advantage of operation at low input voltages. The printed in-plane EGTs we developed exhibit excellent performance with device mobility up to 16 cm2 V–1 s–1, an ION/IOFF ratio of 105, and a subthreshold slope of 120 mV dec–1.