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Basics of Project Management
(2022)
A new approach to determine the elements carbon, hydrogen, nitrogen and oxygen (CHNO) in polymers by wavelength-dispersive X-ray fluorescence analysis (WDXRF) in combination with partial least squares (PLS) regression was explored. The quantification of CHNO was achieved by using the Rayleigh and Compton scattering spectra of an Rh X-ray tube from 84 different polymers. Concealed differences of the corresponding scattering spectra could be utilized to quantify CHNO in a multivariate manner. It was shown that the developed model was capable of determining these commonly non-measurable matrix elements in polymers using WDXRF. Furthermore, the influence of spectral resolution, which is given by the collimator and the crystal, on the prediction of CHNO was explored in this study. It was found that minimal spectral resolution led to the most accurate CHNO predictions. Information about matrix composition could be used to improve so-called semi-quantitative XRF methods based on fundamental parameters (FP) for the analysis of plastics, soil or other samples with high organic content.
Indicators for the optimization of sustainable urban energy systems based on energy system modeling
(2022)
Background: Urban energy systems are responsible for 75 % of the world's energy consumption and for 70 % of the worldwide greenhouse gas emissions. Energy system models are used to optimize, benchmark and compare such energy systems with the help of energy sustainability indicators. We discuss several indicators for their basic suitability and their response to changing boundary conditions, system structures and reference values. The most suitable parameters are applied to four different supply scenarios of a real-world urban energy system.
Results: There is a number of energy sustainability indicators, but not all of them are suitable for the use in urban energy system optimization models. Shortcomings originate from the omission of upstream energy supply chains (secondary energy efficiency), from limited capabilities to compare small energy systems (energy productivity), from excessive accounting expense (regeneration rate), from unsuitable accounting methods (primary energy efficiency), from a questionable impact of some indicators on the overall system sustainability (self-sufficiency), from the lack of detailed information content (share of renewables), and more. On the other hand, indicators of absolute greenhouse gas emissions, energy costs, and final energy demand are well suitable for the use in optimization models. However, each of these indicators only represents partial aspects of energy sustainability; the use of only one indicator in the optimization process increases the risk that other important aspects will deteriorate significantly, eventually leading to suboptimal or even unrealistic scenarios in practice. Therefore, multi-criteria approaches should be used to enable a more holistic optimization and planning of sustainable urban energy systems.
Conclusion: We recommend multi-criteria optimization approaches using the indicators of absolute greenhouse gas emissions, absolute energy costs, and absolute energy demand. For benchmarking and comparison purposes, specific indicators should be used and therefore related to the final energy demand, respectively the number of inhabitants. Our example scenarios demonstrate modeling strategies to optimize sustainability of urban energy systems.
Mechanical ventilation of buildings is generally based on steadily operating systems. This field is well known and established. But, an approach based on time-varied supply flow rates might improve indoor air quality, comfort, and energy consumption. Typical time-scales of the variation are in the order of seconds or minutes. Until now, the effects of unsteady ventilation scenarios are not fully described and so, reliable dimensioning rules are missing. Hence, with a better understanding of the flow in unsteady ventilation, systems can be calculated and optimised. To understand the effective mechanisms and derive functional relations between the flow field and variation parameters, full-field optical flow measurements are executed with a particle image velocimetry (PIV) system. Experiments are conducted under isothermal conditions in water in a small-scale room model (1.00 m × 0.67 m × 0.46 m) with two swirl ceiling diffusers, Reynolds-scaling assures similarity. In a series of experiments, the effects of different unsteady ventilation strategies on the flow fields are investigated and compared to steady conditions with the same mean exchange rate. Mean exchange rates, signal types, periods, and amplitudes are varied. Time-averaged normalised velocity fields already indicate notable differences between steady and unsteady cases especially for lower exchange rates: the distribution is more homogeneous in unsteady scenarios compared to steady conditions, and low-velocity areas are reduced while the mean velocity of the room increases. So, unsteady ventilation might be beneficial in terms of improved ventilation and energy savings in partial-load operation. Fast Fourier Transformation (FFT) analyses of the mean velocity for each field over the whole series detect the main frequency of the volume flow variation. By dividing the velocity field into smaller areas, this main frequency is still detected especially in the upper part of the room, but side frequencies play a role in the room as well.
University students’ mental health and well-being is a growing public health concern. There is a lack of studies assessing a broad range of mental health domains by sex and academic level of study. This cross-sectional online survey of BSc, MSc, and PhD students (n = 3353, 67% female) enrolled at one university in Germany assessed a wide scope of mental health domains, covering positive (i.e., self-rated health, self-esteem, student engagement) and negative aspects (i.e., perceived stress, irritation, and screening positive for depression, anxiety, comorbidity, and psychological distress). We evaluated differences in mental health by sex and academic level. Overall, although self-rated health did not differ by sex and academic level, females and lower academic level were associated with less favorable mental health. Males reported higher prevalence of high self-esteem, and higher engagement (all p ≤ 0.04). Conversely, mean perceived stress and cognitive/emotional irritation were higher among females, as were rates for positive screenings for anxiety, anxiety and depression comorbidity, and psychological distress (p < 0.001 for all). Likewise, lower academic level (BSc) was associated with lower rates of high self-esteem (p ≤ 0.001), increased perceived stress (p < 0.001), and higher prevalence of positive screening for depression, anxiety, comorbidity, and psychological distress (p ≤ 0.002 for all), while higher academic level (PhD) was linked to increased student engagement (p < 0.001 for all). Although the effect sizes of sex and academic level on student mental health were modest, these findings support a need for action to establish and expand early detection and prevention programs, on-campus advisory services, and peer counseling that focus on the sex-specific and academic-study-level-specific factors, as well as mental health and career development resources for students. Academics and policy makers need to consider multipronged intervention strategies to boost confidence of students and their academic career.
Study Programme Development
(2022)
The PAQAF – the Pan-African Quality Assurance and Accreditation Framework – is an overarching framework for several action lines and instruments related to the convergence of the African Higher Education sector, and more specifically quality assurance and accreditation. It was adopted by the Specialized Technical Committee (STC) on Education, Science and Technology of the African Union Assembly in 2016. The implementation of some of the PAQAF’s action lines and the development of some of its instruments has been supported by the HAQAA initiative from 2015 to 2018 and is currently continued in the context of HAAQA2. Module 1 gives an overview of the PAQAF's deveopment and action lines.
The concern for the environment among European consumers is growing and in the future the need for sustainable shopping is expected to increase. Through transparent on-packaging communication with consumers, organic producers have the opportunity to show attributes of organic production system and build a strong market position. The aim of the study was to analyse voluntary packaging information on organic milk from four European markets in the context of organic food quality, i.e., Germany, the Netherlands, Italy and Poland. More specifically, the textual content of 106 organic milk packages was analysed and voluntary information on each package was categorized according to process- and product-related organic milk attributes. The assortment and content of voluntary packaging information varied across the four countries. The largest number of products was found on the German market (37) and the smallest on the Polish market (14). Dutch milk had the greatest amount of voluntary information on animal welfare, product locality, environmental protection, quality confirmation, naturalness and nutritional value. German milk had the most information on enjoyment and conditions of processing, while the Italian milk on the social perspective. The products available on the Polish market had the least voluntary information. Pasteurized organic milk had noticeably more information about organic quality attributes than micro filtrated and UHT milk.