Bioresource categories : primary, secondary, tertiary and quarternary bioresources

Die „Lecture for Future“ Serie zum Thema „Reststoff- und Nebenprodukt-basierte Bioressourcen“ gibt Eindrücke in die Vielfalt verschiedener Bioressourcen und zum Status-quo ihres Managements. Darüber hinaus werden Eindrücke vermittelt, wie diese zukünftig besser verwertet werden können, z.B. in Bioraffinerien zur parallelen Herstellung verschiedener bio-basierter Produkte. Die erste der vier Lern-Einheiten behandelt das Thema „Bioressourcen Kategorien – primäre, sekundäre, tertiäre und quaternäre Bioressourcen“. Es werden zunächst allgemeine Grundlagen zum Thema Bioressourcen gegeben und einige Kategorisierungsmöglichkeiten genannt. Daraufhin wird das Konzept der vier Bioressourcen-Kategorien vorgestellt und die Kategorien allgemein sowie anhand von Beispielen erörtert. Die Kategorisierung von Bioressourcen in primäre, sekundäre, tertiäre und quaternäre Bioressourcen hilft bei der Gestaltung effizienter Nutzungspfade. Die Kategorisierung kann dazu beitragen, eine ineffiziente Nutzung von Bioressourcen zu vermeiden und die Verwendung einer hochwertigen Bioressource für die Herstellung eines geringwertigen Produkts zu verhindern. Die hier gespeicherten Unterlagen umfassen die Print-Version der Lern-Einheit. Die originale, inter-aktive Version ist unter folgendem Link zu finden: https://www.hoou.de/projects/lff/pages/residue-and-by-product-based-bioresourcesThe "Lecture for Future" series on the topic of "Residual and by-product-based bioresources" gives an impression of the diversity of different bioresources and the status quo of their management. Furthermore, impressions are given on how these can be better utilised in the future, e.g. in biorefineries for the parallel production of different bio-based products. The first of the four learning units deals with the topic "Bioresource categories - primary, secondary, tertiary and quaternary bioresources". First, general basics on the topic of bioresources are given and some categorisation possibilities are mentioned. Then the concept of the four bioresource categories is introduced and the categories are discussed in general and with examples. The categorisation of bioresources into primary, secondary, tertiary and quaternary bioresources helps to design efficient utilisation pathways. Categorisation may help to avoid an inefficient bioresource use and to prevent the use of a high-quality bioresource for the production of a low-value product. The documents stored here comprise the print version of the learning unit. The original, interactive version can be found at the following link: https://www.hoou.de/projects/lff/pages/residue-and-by-product-based-bioresourcesTechnische Universität Hambur

A 3/2-approximation for the metric many-visits path TSP

In the Many-visits Path TSP, we are given a set of n cities along with their pairwise distances (or cost) c(uv), and moreover each city v comes with an associated positive integer request r(v). The goal is to find a minimum-cost path, starting at city s and ending at city t, that visits each city v exactly r(v) times. We present a 3/2-approximation algorithm for the metric Many-visits Path TSP, that runs in time polynomial in n and poly-logarithmic in the requests r(v). Our algorithm can be seen as a far-reaching generalization of the 3/2-approximation algorithm for Path TSP by Zenklusen (SODA 2019), which answered a long-standing open problem by providing an efficient algorithm which matches the approximation guarantee of Christofides' algorithm from 1976 for metric TSP. One of the key components of our approach is a polynomial-time algorithm to compute a connected, degree bounded multigraph of minimum cost. We tackle this problem by generalizing a fundamental result of Király, Lau and Singh (Combinatorica, 2012) on the Minimum Bounded Degree Matroid Basis problem, and devise such an algorithm for general polymatroids, even allowing element multiplicities. Our result directly yields a 3/2-approximation to the metric Many-visits TSP, as well as a 3/2-approximation for the problem of scheduling classes of jobs with sequence-dependent setup times on a single machine so as to minimize the makespan

Increasing tightness by introduction of intertemporal constraints in MILP unit commitment

Flexibility requirements of controllable units in energy systems increase with high shares of volatile renewable energy (VRE) production. In this work, an existing unit commitment optimisation, formulated as mixed-integer linear problem (MILP) for energy systems is extended with intertemporal constraints to achieve a more realistic and detailed portrayal of the producer park against the backdrop of need for higher flexibilities. Those extensions mainly consider start-up times as well as minimum operating and standstill periods from a technical perspective, which are associated with rising complexity as well as tightness of the MILP. A small-scale energy system designed as a single copper plate with island restrictions, consisting of a conventional power plant, a short-term and a long-term energy storage and a VRE producer park is used to investigate the effects of the integrated intertemporal constraints. The study shows, that unit commitment is widely influenced by these extensions and the scattering of units, observed in the reference system without these extensions, is eliminated. The number of starts and operating hours therefore results in a more realistic unit commitment. Even though the equation numbers of the MILP increases drastically, the computation time is lowered significantly

Arsenate removal from drinking water using by-products from conventional iron oxyhydroxides production as adsorbents coupled with submerged microfiltration unit

© 2020, The Author(s). Arsenic is among the major drinking water contaminants affecting populations in many countries because it causes serious health problems on long-term exposure. Two low-cost micro-sized iron oxyhydroxide-based adsorbents (which are by-products of the industrial production process of granular adsorbents), namely, micro granular ferric hydroxide (μGFH) and micro tetravalent manganese feroxyhyte (μTMF), were applied in batch adsorption kinetic tests and submerged microfiltration membrane adsorption hybrid system (SMAHS) to remove pentavalent arsenic (As(V)) from modeled drinking water. The adsorbents media were characterized in terms of iron content, BET surface area, pore volume, and particle size. The results of adsorption kinetics show that initial adsorption rate of As(V) by μTMF is faster than μGFH. The SMAHS results revealed that hydraulic residence time of As(V) in the slurry reactor plays a critical role. At longer residence time, the achieved adsorption capacities at As(V) permeate concentration of 10 μg/L (WHO guideline value) are 0.95 and 1.04 μg/mg for μGFH and μTMF, respectively. At shorter residence time of ~ 3 h, μTMF was able to treat 1.4 times more volumes of arsenic-polluted water than μGFH under the optimized experimental conditions due to its fast kinetic behavior. The outcomes of this study confirm that micro-sized iron oyxhydroxides, by-products of conventional adsorbent production processes, can successfully be employed in the proposed hybrid water treatment system to achieve drinking water guideline value for arsenic, without considerable fouling of the porous membrane

Simultaneous topology and fastener layout optimization of assemblies considering joint failure

This paper provides a method for the simultaneous topology optimization of parts and their corresponding joint locations in an assembly. Therein, the joint locations are not discrete and predefined, but continuously movable. The underlying coupling equations allow for connecting dissimilar meshes and avoid the need for remeshing when joint locations change. The presented method models the force transfer at a joint location not only by using single spring elements but accounts for the size and type of the joints. When considering riveted or bolted joints, the local part geometry at the joint location consists of holes that are surrounded by material. For spot welds, the joint locations are filled with material and may be smaller than for bolts. The presented method incorporates these material and clearance zones into the simultaneously running topology optimization of the parts. Furthermore, failure of joints may be taken into account at the optimization stage, yielding assemblies connected in a fail-safe manner.Bundesministerium für Wirtschaft und Energie - BMWiDeutsche Forschungsgemeinschaft (DFG

Mapping the sea of opportunities : Blockchain in supply chain and logistics

Driven by successful pilot projects in supply chain and logistics, Blockchain has become one of the industry’s latest technology hypes. In this paper, we cut through the hype and shed light on the expectations of industry professionals towards the benefits and challenges of Blockchain. Also, we categorize current Blockchain applications that are expected to provide tangible benefits for supply chain and logistics processes. To explore such potentials, we argue that companies should gain own first-hand experiences through small-scale experiments

Investigation of nonlinear wave-ice interaction using parameter study and numerical simulation

This paper investigates the question of the existence of nonlinear wave-ice interaction with the focus on nonlinear wave propagation and dispersion of waves. The scope of this investigation is to provide a better understanding of ice and wave conditions required to observe nonlinear wave effects under level ice. Direct numerical simulations of nonlinear waves in solid ice are performed within the weakly nonlinear Schrödinger equation (NLSE) framework, using the theoretical findings from Liu and Mollo-Christensen’s 1988 paper. Systematic variations of wave and ice parameters address the impact of the mechanical ice properties and ice thickness on traveling waves of certain wave lengths. The impacts of parameter characteristics on nonlinear focusing and wave dynamics, as well as possible constraints regarding physical consistency, are discussed. It is presented that nonlinear focusing in level ice occurs theoretically. Hereby, distinctive areas of validity with respect to nonlinear wave focusing are identified within the parameter study, which strongly depends on the material properties of the level ice. The results obtained in the parameter study are subsequently used to investigate wave focusing under level ice. Therefore, an exact solution of the NLSE, the Peregrine breather, is utilized. The analytical solution for level ice is compared to the open water solution and accompanied by direct numerical simulations. These investigations show that nonlinear wave focusing can be predicted under level ice for certain parameters. In addition, the agreement of the direct simulations and the analytic solution verifies the numerical approach for nonlinear waves in solid ice.Deutsche Forschungsgemeinschaft (DFG

Electrical double layer capacitance of curved graphite electrodes

To improve the understanding of the relation between electrode curvature and energy storage mechanisms, a systematic investigation of the correlation between convex and concave electrode surfaces and the differential capacitance of an electrochemical double layer capacitor using molecular dynamics simulations is presented. Each electrode consists of three layers of curved graphene sheets with a convex and concave surface to which the constant potential method was applied. The differential capacitance shows a fluctuating behavior with respect to the curvature radius of the convex and concave areas of the electrode. The reasons identified for this are differences in the geometric arrangement and solvation of the adsorbed ions as well as a steric hindrance prohibiting further charge accumulation. Because the total differential capacitance is calculated as a weighted average of contributions from concave and convex surfaces, the influence of individual curvatures on the total capacitance is significantly reduced for the total electrode surface.Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) - Projektnummer 192346071 - SFB 986 and - Projektnummer 390794421 - GRK 2462

Computability theory

Die Veröffentlichung gibt eine Einführung in die Theorie der Berechenbarkeit.The publication provides an introduction to computability theory