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Optimised Nutrient Recovery from Biogas Digestate by Solid/Liquid Separation and Membrane Treatment
(2019)
Anaerobic digestion products of agricultural biogas plants are characterised by high nitrogen, phosphorus, and potassium content. In three scale-up steps, a membrane based digestate treatment process of solid-liquid-separation, ultrafiltration, and reverse osmosis for nutrient recovery was investigated. Lab-scale trials delivered a very good understanding of fluid properties and subsequent ultrafiltration performance, which is the limiting process step in terms of energy demand and operation costs. In semi-technical experiments, optimisation, and design parameters were developed, which were subsequently applied to pilot-scale tests at two full-scale biogas plants. The process optimisation resulted in 50 % energy reduction of the ultrafiltration step. About 36 % of the sludge volume was recovered as dischargeable water, 20 % as solid N/P-fertiliser, and 44 % as liquid N/K-fertiliser.
The usage of high-level synthesis (HLS) tools for FPGAs has increased significantly over the last years since they matured and allow software programmers to take advantage of reconfigurable hardware technology.
Most HLS tools employ methods to optimize for loops, e. g. by unrolling or pipelining them. But there is hardly any work on the optimization of while loops. This comes at no surprise since most while loops have loop-carried dependences involving the loop condition which result in large recurrence cycles in the dataflow graphs. Therefore typical while loops cannot be parallelized or pipelined.
We propose a novel transformation which allows to optimize while loops nested within a for loop. By interchanging the two loops, it is possible to pipeline (and thereby parallelize) the inner loop, resulting in a reduced execution time. We present two case studies on different hardware platforms and show the speedup factors - compared to a host processor and to an unoptimized hardware implementation - achieved by our while loop optimization method.
A recently published study of high temperature nitridation of iron chromium aluminum alloys (FeCrAl) at 900°C in N2–H2 has redundantly shown the formation of locally confined corrosion pockets reaching several microns into the alloy. These nitrided pockets form underneath chromia islands laterally surrounded by the otherwise protective alumina scale. Chromia renders a nitrogen‐permeable defect under the given conditions and the presence of aluminum in the alloy. In light of these findings on FeCrAl, a focused ion beam–scanning electron microscope tomography study has been undertaken on an equally nitrided FeNiCrAl sample to characterize its nitridation corrosion features chemically and morphologically. The alloy is strengthened by a high number of chromium carbide precipitates, which are also preferential chromia formation sites. Besides the confirmation of the complete encapsulation of the corrosion pocket from the alloy by a closed and dense aluminum nitride rim, very large voids have been found in the said pockets. Furthermore, metallic particles comprising nickel and iron are deposited on top of the outer oxide scale above such void regions.
Keynes’ Grandchildren and Easterlin’s Paradox. What Is Keeping Us from Reducing Our Working Hours?
(2019)
In 1930 Keynes famously predicted that 100 years later-i.e. in 2030-the “economic problem” would be solved and we would be living in an “age of leisure and of abundance” working only 3 h a day. In the same text, Keynes stated that there are absolute and relative needs (“in the sense that we feel them only if their satisfaction lifts us above, makes us feel superior to, our fellows”), but he thought that relative needs are of minor importance. Richard Easterlin’s work, on the other hand, suggests that relative needs are pervasive and that wellbeing depends much more on one’s relative income than Keynes once thought.
It will be argued in this text that Richard Easterlin’s findings, in spite of proving Keynes off the mark in his understatement of relative needs, strengthens the case for working time reductions: the larger the proportion of goods subject to the relative-income effect, the greater are the benefits of working fewer hours. Perhaps the main explanation for why we are still sticking to the 40-h work-week is that the Easterlin paradox has not been widely understood yet.
The deployment of containers as building modules has grown in popularity over the past years due to their inherent strength, modular construction, and relatively low cost. The upcycled container architecture is being accepted since it is more eco-friendly than using the traditional building materials with intensive carbon footprint. Moreover, owing to the unquestionable urgency of climate change, existing climate-adaptive design strategies may no longer respond effectively as they are supposed to work in the previous passive design. Therefore, this paper explores the conceptual design for an upcycled shipping container building, which is designed as a carbon-smart modular living solution to a single family house under three design scenarios, related to cold, temperate, and hot–humid climatic zones, respectively. The extra feature of future climate adaption has been added by assessing the projected future climate data with the ASHRAE Standard 55 and Current Handbook of Fundamentals Comfort Model. Compared with the conventional design, Rome would gradually face more failures in conventional climate-adaptive design measures in the coming 60 years, as the growing trends in both cooling and dehumidification demand. Consequently, the appropriate utilization of internal heat gains are proposed to be the most promising measure, followed by the measure of windows sun shading and passive solar direct gain by using low mass, in the upcoming future in Rome. Future climate projection further shows different results in Berlin and Stockholm, where the special attention is around the occasional overheating risk towards the design goal of future thermal comfort.
Positive factors are increasingly recognized in the field of psychology, however, few studies have investigated the longitudinal measurement invariance (LMI) and reciprocal associations of positive core constructs, such as happiness, life satisfaction and positive mental health. This study evaluated the LMI of these constructs over four years in a Chinese Student Sample (n = 4400) using the Subjective Happiness Scale (SHS), the Satisfaction with Life Scale (SWLS) and the Positive Mental Health Scale (PMH-scale). The longitudinal reciprocal associations of the constructs were examined within a random intercept cross-lagged panel model (RI-CLPM). The results show that the SHS, SWLS and PMH-scale are measurement invariant over time and that the constructs are positively inter-related, but show different reciprocal patterns over time.
Background:
While aiming for the same goal of building a national eHealth Infrastructure, Germany and the United States pursued different strategic approaches – particularly regarding the role of promoting the adoption and usage of hospital Electronic Health Records (EHR).
Objective:
To measure and model the diffusion dynamics of EHRs in German hospital care and to contrast the results with the developments in the US.
Materials and methods:
All acute care hospitals that were members of the German statutory health system were surveyed during the period 2007–2017 for EHR adoption. Bass models were computed based on the German data and the corresponding data of the American Hospital Association (AHA) from non-federal hospitals in order to model and explain the diffusion of innovation.
Results:
While the diffusion dynamics observed in the US resembled the typical s-shaped curve with high imitation effects (q = 0.583) but with a relatively low innovation effect (p = 0.025), EHR diffusion in Germany stagnated with adoption rates of approx. 50% (imitation effect q = -0.544) despite a higher innovation effect (p = 0.303).
Discussion:
These findings correlate with different governmental strategies in the US and Germany of financially supporting EHR adoption. Imitation only seems to work if there are financial incentives, e.g. those of the HITECH Act in the US. They are lacking in Germany, where the government left health IT adoption strategies solely to the free market and the consensus among all of the stakeholders.
Conclusion:
Bass diffusion models proved to be useful for distinguishing the diffusion dynamics in German and US non-federal hospitals. When applying the Bass model, the imitation parameter needs a broader interpretation beyond the network effects, including driving forces such as incentives and regulations, as was demonstrated by this study.
Purpose
In a knowledge-based society, one of the main driving forces of prosperity at city and regional levels is the ability to attract students and recently qualified graduates. The purpose of this paper is to identify the urban factors that contribute to “attractiveness” from a student perspective and to subsequently analyse the influence of these factors on students’ location choices. In the corresponding case study, the criteria identified were used to evaluate student satisfaction with the German city of Osnabrück.
Design/methodology/approach
A multi-level empirical research concept was used to analyse the relevant criteria. Focus group discussions served as the basis to design and conduct a survey of almost 2,300 students in the university city of Osnabrück at the end of 2016. A follow-up study in November 2017 at two universities in Berlin provided data for comparison.
Findings
Accessible – safe – clean and with affordable housing: these terms sum up the core expectations that students have of an attractive city. In contrast to the findings of Richard Florida regarding the creative class, cultural opportunities, exciting nightlife and a multicultural population were not important factors among the survey participants.
Research limitations/implications
As the study was conducted in two cities only, the findings cannot be generalised. It should be replicated in at least five other cities to validate and compare the research findings presented here. Furthermore, this study focused on the factors influencing the attractiveness of the city as a whole. However, the attractiveness of a specific neighbourhood may be of greater relevance to the decision-making process. As housing plays a major role, students’ particular needs with regard to accommodation should also be examined at greater depth.
Practical implications
Insights generated by the empirical study provide relevant information that may assist city stakeholders in taking effective measures regarding place management to attract and retain students.
Originality/value
To date, little research has been undertaken to empirically examine the specific factors that German students look for when deciding where to study and live. The goal of this paper is to present new empirical insights concerning the quality-of-life factors that influence students’ decision-making processes.
Aim
Manual cranial bone tissue techniques (CBTT) are used by physiotherapists as a tool for assessment and treatment of complaints in the craniocervical, face, and head regions. The goal of this study was to determine whether CBTT were able to discriminate between subjects with cervical and/or temporomandibular disorders (TMD) and a healthy group. In addition, the inter-rater reliability when applying CBTT was also investigated.
Methods
A cross-sectional study was conducted and included 60 participants. Six standardized passive techniques were applied and judged for resistance, compliance, and sensory answer. In order to evaluate the inter-rater reliability of these techniques a cohort of participants was measured twice (by two evaluators) prospectively. A logistic regression model and Receiver Operating Curve (ROC) analyses were used to determining the discriminative validity of these techniques.
Results
Logistic regression identified a significant difference for five techniques for resistance and/or compliance and/or the sensory answer between the groups. Based on the Area Under the Curve (AUC) analysis, the discriminative ability of the temporal rotation to distinguish between the groups was fair to good (for resistance AUC = 0.7775 and for compliance AUC = 0.8065). The highest agreement between the two assessors was for the resistance with occipital compression (73%) technique.
Conclusion
This study highlights that some of the CBTT could be potentially useful in distinguishing subjects with cervical and/or TMD from healthy subjects. Inter-rater reliability was moderate. CBTT could be potentially integrated in the examination of participants with complaints in the craniofacial region.