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Institute
Development of a modelling and simulation methodology for
hierarchical energy system scenarios
(2019)
In the context of renewable energies, precise and reliable forecasts are necessary to ensure a sustainable and economic operation of energy systems. This paper presents a methodology and environment that allows modelling, simulation and analysis of decentralized and heterogeneous energy system scenarios on a virtual level. An essential requirement for the modelling and simulation of complex network scenarios is a capable abstraction strategy, which allows hierarchical clustering and interaction of several network levels. The approach presented in this contribution provides mechanisms that allow a realistic modelling of complex energy system scenarios covering several network levels, taking into account the specific components, interactions and relationships that exist at each level (e.g. specific electrical lines etc.). The simulation follows a hierarchical tree-based approach, which allows to integrate already existing simulation models into the
environment and to generate only a small overhead over the simulation run time. As we can show, the developed environment not only serves as an excellent basis for analysis and optimization purposes but also for the application of artificial intelligence techniques, as it supports the effective generation of training data and verification of optimization results.
Essenzielle Voraussetzung für die erfolgreiche Durchführung von
Stabilitätsstudien mit Betäubungsmitteln (BtM) ist, dass neben den
Anforderungen von GMP und ICH auch die des Betäubungsmit-
telgesetzes vollumfänglich umgesetzt werden. Ein reibungsloser
Projektablauf lässt sich mit einer klaren Strategie unter Einbezug
eines Dienstleisters erreichen, der die erforderliche Kapazität für
die BtM-Aufbewahrung, die Erlaubnis zum Umgang mit verschie-
denen BtM-Stoffen und die entsprechende Expertise aufweist. Für
den Sponsor resultieren daraus eine Einsparung enormer Investi-
tionskosten, die Entlastung seines BtM-Verantwortlichen sowie
eine deutliche Reduktion von BtM-Verkehr und Dokumentations-
aufwand.
Purpose
More than 50 per cent of all German households own a freezing appliance and so far the market of frozen foods is constantly increasing (1 per cent from 2017 to 2018). Despite frozen foods playing an important role in our everyday life, little is known about the consumer’s habits at home. The purpose of this paper is to uncover gaps in the knowledge about consumer behaviour when handling frozen food. Moreover, the impact of consumers on the quality of frozen products should be assessed.
Design/methodology/approach
A representative online survey was carried out to investigate different aspects of consumer behaviour concerning frozen foods. Respondents (n=2,053) were questioned about their general handling habits regarding eight different food groups: fruit, vegetables, meat, fish, bread, pastries, ready-to-eat meals and leftovers. The focus was on freezing, pre-handling, packaging and thawing – depending on the age of those questioned and combined with best practice advice regarding quality storage of frozen products.
Findings
Most Germans have the opportunity to freeze food and keep their freezers full or medium loaded. Older participants act more efficiently towards quality storage, but more education about freezing and frozen storage would be generally helpful to maintain quality of frozen foods and increase utilisation of freezers, using their full preservation potential.
Research limitations/implications
No open questions were asked due to the scope of more than 2,000 participants, which, in retrospect, would have been instructive.
Originality/value
Consumer handling of frozen food in Germany was investigated in a representative way for the first time, covering age groups from 18 to 69 and household sizes from 1 to 4 people, focussing on eight major food groups.
In Kühlgeräten finden sich zunehmend feuchtegeregelte Systeme für die Gemüselagerung, für welche jedoch keine Bewertungsgrundlagen zur Funktionsanalyse bestehen. Anhand vergleichender Lagertests wird der Einfluss feuchtegeregelter Lagersysteme auf den Qualitätserhalt von Gemüse ermittelt. Als Leitparameter eignet sich der Frischmasseverlust; die Analyse der Farbveränderung kann als unterstützende Prüfmethode dienen.
The wholesale and retail industry is the fourth largest contributor to South Africa’s Gross Domestic Product. However, it faces the major challenge of attracting highly skilled and motivated workers. Although South African universities launched programs in retail management, attracting young talents to a career in retailing remains a tough challenge. Drawing on previous findings from the field of graduate decision-making and industry image from other countries, this research examines the perceptions and expectations of Gen Y members with regard to their field of study and their prospective career. A nationwide survey with 1363 South African first year students, in their first week at university, shows significant differences between freshmen enrolled in retail business management and those enrolled in other business majors. While retail students, as compared to other participants, tend to hold stronger positive associations with their field of study and a retail career, majoring in retailing appears to be a fallback option. Over all participants, the analysis reveals that the perception of retailing careers primarily exceeds expectations on attributes that are only of minor importance. When it comes to important career attributes like payment, work-life balance and advancement issues, the retail image lags behind that of other industries. Comparing the field of study with the preferred industry, we identify four different segments of students that qualify to be targeted by companies and universities in different ways.
Many software tools provide facilities for depicting reaction network diagrams in a visualform. Two aspects of such a visual diagram can be distinguished: the layout (i.e.: the po-sitioning and connections) of the elements in the diagram, and the graphical form of theelements (for example, the glyphs used for symbols, the properties of the lines connectingthem, and so on). For software tools that also read and write models in SBML (Systems Bi-ology Markup Language) format, a common need is to store the network diagram togetherwith the SBML representation of the model. This in turn raises the question of how toencode the layout and the rendering of these diagrams. TheSBML Level 3 Version 1 Corespecification does not provide a mechanism for explicitly encoding diagrams, but it doesprovide a mechanism for SBMLpackagesto extend the Core specification and add addi-tional syntactical constructs. TheLayoutpackage for SBML Level 3 adds the necessaryfeatures to SBML so that diagram layouts can be encoded in SBML files, and a companionpackage called SBMLRenderingspecifies how the graphical rendering of elements can beencoded.The SBML Layout package is based on the principle that reaction network diagrams shouldbe described as representations of entities such as species and reactions (with direct links tothe underlying SBML elements), and not as arbitrary drawings or graphs; for this reason,existing languages for the description of vector drawings (such as SVG) or general graphs(such as GraphML) cannot be used.
Environmental antibiotic-resistant bacteria (ARB) can be transferred to humans through foods. Fresh produce in particular is an ideal vector due to frequent raw consumption. A major contamination source of fresh produce is irrigation water. We hypothesized that water quality significantly affects loads of ARB and their diversity on fresh produce despite various other contamination sources present under agricultural practice conditions. Chive irrigated from an open-top reservoir or sterile-filtered water (control) was examined. Heterotrophic plate counts (HPC) and ARB were determined for water and
chive with emphasis on Escherichia coli and Enterococcus spp. High HPC of freshly planted chive decreased over time and were significantly lower on control- vs. reservoir-irrigated chive at harvest (1.3 log (CFU/g) lower). Ciprofloxacin- and ceftazidime-resistant bacteria were significantly lower on control-irrigated chive at harvest and end of shelf life (up to 1.8 log (CFU/g) lower). Escherichia coli and Enterococcus spp. repeatedly isolated from water and chive proved resistant to up to six or four antibiotic classes (80% or 49% multidrug-resistant, respectively). Microbial source tracking identified E. coli-ST1056 along the irrigation chain and on chive. Whole-genome sequencing revealed that E. coli-ST1056 from both environments were clonal and carried the same transmissible multidrug-resistance plasmid, proving water as source of chive contamination. These findings emphasize the urgent need for guidelines concerning ARB in irrigation water and development of affordable water disinfection technologies to diminish ARB on irrigated produce.
A novel electrode fabrication method based on liquid doping of PEDOT-PSS onto PET-G film by drop casting is reported. A dispersed liquid-PEDOT-PSS solution is prepared as an ink by a liquid doping synthesis method. The EG/DMSO:PEDOT-PSS solution is then drop cast onto oxygen plasma-modified PET-G films for electrode fabrication. Their surface topography and electrochemical characteristics are characterized. The results show that the prepared electrode material has an electrical conductivity of 11661.7 and 11528.8 S/m for EG- and DMSO-treated PEDOT-PSS films, respectively. Ink formulation achieves unprecedented conductivity via spontaneous liquid wicking. The specific capacitance is 134 F/g at a scanning rate of 5 mV/s and 309.6 F/&g at a scanning rate of 20 mV/s for EG and DMSO-treated PEDOT-PSS films, respectively, on the three-electrode system while specific capacitance for pristine PEDOT-PSS calculated at 80 mV/s is 4.6 F/g. PEDOT-PSS films are engineered for superior supercapacitor performance through liquid wicking. Moreover, the results of Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and Raman spectroscopy measurements confirm that the removal of PSS on the surface is due to liquid–liquid doping. Energy-dispersive X-ray spectroscopy analysis proves the expulsion of PSS molecules from the solution interface. Therefore, the die-cast PET-G-PEDOT-PSS electrode is a promising candidate for advanced supercapacitor applications.
SummaryThree‐dimensional food printing (3DFP) can produce foods with tailored nutritional content, complex shapes and textures. This technology requires food formulations (food inks) with specific rheological properties. Pickering emulsions (PE) have gained attention due to their long‐term stability and desirable printable properties, making them an excellent candidate for 3DFP. The purpose of this study is to use bibliometric analysis to identify the most important scientific research on PE used in 3DFP. This includes identifying key authors, countries and universities or institutions where the research was conducted, as well as the primary journals that provide information on this topic. Our study provides insight into the relevance of food ink properties for next‐generation 3DFP and the main raw materials used for the development of PE. Out of the 28 original research articles analysed, only 10 countries have studied the application of PE for 3DFP. China and the United Kingdom have been the primary leaders in researching this topic. The Food Hydrocolloids Journal has been the main source of scientific information. The studies cited Pickering stabiliser particles, including soy protein isolate, microcrystalline cellulose and acetylated microcrystalline cellulose, as well as oil phases based on sunflower, canola, olive and soybean oils. High internal phase Pickering emulsions (HIPPEs) have shown great thermal and conductive stability, making them a promising choice for 3DFP post‐processing. Further studies should assess the bioavailability and bioaccessibility of the bioactive compounds that are encapsulated. It is also important to explore their potential use in real food systems and to integrate innovative packaging solutions.
Studies on composition optimisation showed that the mixing of nanoclays to whey protein-isolate (WPI)-based coating formulations offers an effective strategy to reduce the oxygen permeability of coated polymer films. The scaling up of the various processing stages of these formulations was undertaken to prove their industrial feasibility. The aim was to investigate the effect of various preparation methods at different production scales (pilot- and semi-industrial scale) on the barrier performance and morphological properties of the applied nanocomposites. A nano-enhanced
composition was converted into a so-called “ready-to-use” formulation by means of a solid-state pre-dispersion process using ball-milling. The process yielded a nearly dust-free, free-flowing powder
containing agglomerated particles, which can easily be mixed with water. The preparation of a coating formulation using the ready-to-use granules and its upscaling for roll-to-roll converting at pilot- and
semi-industrial scale was also successfully implemented. The effects of both the production at various scales and ultrasound treatment on the morphology and barrier performance of the nanocomposites
were characterized by transmission electron microscopy, scanning electron microscopy, as well as oxygen permeability measurements. Results have shown that the addition of nanoclays to WPI-based
coating formulations ultimately led to significantly reduced oxygen permeabilities to 0.59 cm3, 100 μm·m−2·d−1·bar−1 (barrier improvement factor, BIF of 5.4) and 0.62 cm3, 100 μm·m−2·d−1·bar−1
(BIF of 5.1) in cases of pilot- and semi-industrial-processed coatings, respectively, compared to a reference without nanoclay. In both cases, a similar degree of nanoparticle orientation was achieved.
It was concluded that the solid state pre-dispersion of the nanoplatelets during the production of the ready-to-use formulation is the predominant process determining the ultimate degree of nanoparticle orientation and dispersion state.