Governing Transactions and Interdependences between Linked Value Chains in a Circular Economy: The Case of Wastewater Reuse in Braunschweig (Germany)

Reusing wastewater in agriculture has attracted increasing attention as a strategy to support the transition towards the circular economy in the water and agriculture sector. As a consequence, there is great interest in solutions for governing the transactions and interdependences between the associated value chains. This paper explores the institutions and governance structures for coordinating transactions and interdependences between actors in linked value chains of wastewater treatment and crop production. It aims to analyze how transactions and interdependences shape the governance structures for reusing wastewater at the local level. A transaction costs analysis based on data from semi-structured interviews and a questionnaire is applied to the agricultural wastewater reuse scheme of the Wastewater Association Braunschweig (Germany). The results show that different governance structures are needed to match with the different properties and requirements of the transactions and activities between linked value chains of wastewater treatment and crop production. Interdependences resulting from transactions between wastewater providers and farmers increase the need for hybrid and hierarchical elements in the governance structures for wastewater reuse. The authors conclude that aligning governance structures with transactions and interdependences is key to efficiently governing transactions and interdependences between linked value chains in a circular economy. © 2018 by the authors

Mechanical Stress Stability of Flexible Amorphous Zinc Tin Oxide Thin-Film Transistors

Due to their low-temperature processing capability and ionic bonding configuration, amorphous oxide semiconductors (AOS) are well suited for applications within future mechanically flexible electronics. Over the past couple of years, amorphous zinc tin oxide (ZTO) has been proposed as indiumand gallium-free and thus more sustainable alternative to the widely deployed indium gallium zinc oxide (IGZO). The present study specifically focuses on the strain-dependence of elastic and electrical properties of amorphous zinc tin oxide thin-films sputtered at room temperature. Corresponding MESFETs have been compared regarding their operation stability under mechanical bending for radii ranging from 5 to 2 mm. Force-spectroscopic measurements yield a plastic deformation of ZTO as soon as the bending-induced strain exceeds 0.83%. However, the electrical properties of ZTO determined by Hall effect measurements at room temperature are demonstrated to be unaffected by residual compressive and tensile strain up to 1.24 %. Even for the maximum investigated tensile strain of 1.26 %, the MESFETs exhibit a reasonably consistent performance in terms of current on/off ratios between six and seven orders of magnitude, a subthreshold swing around 350 mV/dec and a field-effect mobility as high as 7.5 cm2V−1s−1. Upon gradually subjecting the transistors to higher tensile strain, the channel conductivity steadily improves and consequently, the field-effect mobility increases by nearly 80% while bending the devices around a radius of 2 mm. Further, a reversible threshold voltage shift of about −150 mV with increasing strain is observable. Overall, amorphous ZTO provides reasonably stable electrical properties and device performance for bending-induced tensile strain up to at least 1.26% and thus represent a promising material of choice considering novel bendable and transparent electronics

Hot-phonon effects in photo-excited wide-bandgap semiconductors

Carrier and lattice relaxation after optical excitation is simulated for the prototypical wide-bandgap semiconductors CuI and ZnO. Transient temperature dynamics of electrons, holes as well as longitudinal-optic (LO), transverse-optic (TO) and acoustic phonons are distinguished. Carrier-LO-phonon interaction constitutes the dominant energy-loss channel as expected for polar semiconductors and hot-phonon effects are observed for strong optical excitation. Our results support the findings of recent time-resolved optical spectroscopy experiments

STEM Education as a Vital Preventive Response to a Pandemic

T he extraordinary work to develop feasible vaccines, effective medical treatments, and accurate epidemiological studies to alleviate the SARS-CoV2 pandemic would not have been possible without collaboration between academia, industry, government laboratories, and regulatory agencies that speak the common language researchers around the world know—science

Transparent Flexible Thermoelectric Material Based on Non-toxic Earth-Abundant p-Type Copper Iodide Thin Film

Thermoelectric devices that are flexible and optically transparent hold unique promise for future electronics. However, development of 'invisible' thermoelectric elements is hindered by the lack of p-type transparent thermoelectric materials. Here we present the superior room-temperature thermoelectric performance of p-type transparent copper iodide (CuI) thin films deposited by industrially applicable room-temperature sputtering techniques. The optical transmittance is 60–85% in the visible and near-infrared regions. Large Seebeck coefficients and power factors of the obtained CuI thin films are analyzed based on a single-band model. The low thermal conductivity of the CuI films is attributed to a combined effect of the heavy element iodine and strong phonon scattering. Accordingly, we achieve a large thermoelectric figure of merit of ZT = 0.21 at 300 K for the CuI films, which is three orders of magnitude higher compared with state-of-the-art p-type transparent materials. A transparent and flexible CuI-based thermoelectric element is demonstrated

Schottky contacts to In2O3

n-type binary compound semiconductors such as InN, InAs, or In2O3 are especial because the branch-point energy or charge neutrality level lies within the conduction band. Their tendency to form a surface electron accumulation layer prevents the formation of rectifying Schottky contacts. Utilizing a reactive sputtering process in an oxygen-containing atmosphere, we demonstrate Schottky barrier diodes on indium oxide thin films with rectifying properties being sufficient for space charge layer spectroscopy. Conventional non-reactive sputtering resulted in ohmic contacts. We compare the rectification of Pt, Pd, and Au Schottky contacts on In2O3 and discuss temperature-dependent current-voltage characteristics of Pt/In2O3 in detail. The results substantiate the picture of oxygen vacancies being the source of electrons accumulating at the surface, however, the position of the charge neutrality level and/or the prediction of Schottky barrier heights from it are questioned

Reconstruction of the lipid metabolism for the microalga Monoraphidium neglectum from its genome sequence reveals characteristics suitable for biofuel production

Bogen C, Al-Dilaimi A, Albersmeier A, et al. Reconstruction of the lipid metabolism for the microalga Monoraphidium neglectum from its genome sequence reveals characteristics suitable for biofuel production. BMC Genomics. 2013;14(1): 926.BACKGROUND: Microalgae are gaining importance as sustainable production hosts in the fields of biotechnology and bioenergy. A robust biomass accumulating strainof the genus Monoraphidium (SAG 48.87) was investigated in this work as apotential feedstock for biofuel production. The genome was sequenced, annotated, and key enzymes for triacylglycerol formation were elucidated. RESULTS: Monoraphidium neglectum was identified as an oleaginous species with favourable growth characteristics as well as a high potential for crude oil production, based on neutral lipid contents of approximately 21% (dry weight) under nitrogen starvation, composed of predominantly C18:1 and C16:0 fatty acids. Further characterization revealed growth in a relatively wide pH range and salt concentrations of up to 1.0% NaCl, in which the cells exhibited larger structures. This first full genome sequencing of a member of the Selenastraceae revealed a diploid, approximately 68 Mbp genome with a G + C content of 64.7%. The circular chloroplast genome was assembled to a 135,362 bp single contig, containing 67 protein-coding genes. The assembly of the mitochondrial genome resulted in two contigs with an approximate total size of 94 kb, the largest known mitochondrial genome within algae. 16,761 protein-coding genes were assigned to the nuclear genome. Comparison of gene sets with respect to functional categories revealed a higher gene number assigned to the category "carbohydrate metabolic process" and in "fatty acid biosynthetic process" in M. neglectum when compared to Chlamydomonas reinhardtii and Nannochloropsis gaditana, indicating a higher metabolic diversity for applications in carbohydrate conversions of biotechnological relevance. CONCLUSIONS: The genome of M. neglectum, as well as the metabolic reconstruction of crucial lipid pathways, provides new insights into the diversity of the lipid metabolism in microalgae. The results of this work provide a platform to encourage the development of this strain for biotechnological applications and production concepts

Non-Human and Human Transport to Mars: by Mars- plus Europa-INPPS Flagship Missions including High Mass Science Payload

Summary Status INPPS Flagshi

Planetary Defense Ground Zero: MASCOT's View on the Rocks - an Update between First Images and Sample Return

At 01:57:20 UTC on October 3rd, 2018, after 3½ years of cruise aboard the JAXA spacecraft HAYABUSA2 and about 3 months in the vicinity of its target, the MASCOT lander was separated successfully by from an altitude of 41 m. After a free-fall of only ~5m51s MASCOT made first contact with C-type near-Earth and potentially hazardous asteroid (162173) Ryugu, by hitting a big boulder. MASCOT then bounced for ~11m3s, in the process already gathering valuable information on mechanical properties of the surface before it came to rest. It was able to perform science measurements at 3 different locations on the surface of Ryugu and took many images of its spectacular pitch-black landscape. MASCOT’s payload suite was designed to investigate the fine-scale structure, multispectral reflectance, thermal characteristics and magnetic properties of the surface. Somewhat unexpectedly, MASCOT encountered very rugged terrain littered with large surface boulders. Observing in-situ, it confirmed the absence of fine particles and dust as already implied by the remote sensing instruments aboard the HAYABUSA2 spacecraft. After some 17h of operations, MASCOT‘s mission ended with the last communication contact as it followed Ryugu’s rotation beyond the horizon as seen from HAYABUSA2. Soon after, its primary battery was depleted. We present a broad overview of the recent scientific results of the MASCOT mission from separation through descent, landing and in-situ investigations on Ryugu until the end of its operation and relate them to the needs of planetary defense interactions with asteroids. We also recall the agile, responsive and sometimes serendipitous creation of MASCOT, the two-year rush of building and delivering it to JAXA’s HAYABUSA2 spacecraft in time for launch, and the four years of in-flight operations and on-ground testing to make the most of the brief on-surface mission