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Engineering of an Algal Turf Scrubber (ATS) for phosphate removal from wastewater
No full textWith an increasing population around the world, there is a surge in wastewater generation as well as an eager demand for energy. Carbon dioxide and other pollutants are also released into the atmosphere when fossil fuels are burned for energy production. In order to reduce wastewater treatment costs and create energy, it is crucial to develop sustainable green strategies.
Microalgae could be the best alternative to solve these problems. These can potentially reduce the cost and energy usage of treating wastewater compared to conventional wastewater treatment procedures. Phosphate is one of the critical elements in wastewater, which has to be minimized to a certain level in a wastewater treatment plant. Scientists have been researching cost-effective algal cultivation systems for a long time. In the early 90s, Adey developed the first Algal Turf Scrubber concept. This thesis investigates Algal Turf Scrubber (ATS) to produce microalgae biomass and remove nutrients from wastewater.
In order to build an ATS, various techniques and equipment have been used. An ideal movement system has been created using MATLAB Simulink and Arduino. A 20W blue LED light was used on the basis of 09h:09h (Light : Dark). In this study, two algal turf scrubbers were constructed.
External liquid phosphate was used with the Spoy Kanal water in order to increase the phosphate level, as the Spoy Kanal water contains a very low phosphate. On average, the rate of 0.65 mg/L per day phosphate and 0.41 mg/L per day nitrate removal were recorded in 12 days of operatio
1/2021 Zweite Änderungssatzung zur Prüfungsordnung für den Bachelorstudiengang Mechatronic Systems Engineering der Fakultät Technologie und Bionik an der Hochschule Rhein-Waal
No full textDie Mediengrundrechte des Art. 5 GG in der Rechtsprechung des Bundesverfassungsgerichts
No full textIn diesem Arbeitspapier, das an der Fakultät für Kommunikation und Umwelt der Hochschule Rhein-Waal entstanden ist, werden die juristischen Grundlagen und aktuellen Fälle der Rechtsprechung erörtert und mit genauen Quellenangaben versehen.
Die Mediengrundrechte sollen es ermöglichen, dass jeder seine Meinung frei äußern kann, ohne dafür belangt werden zu können. Dies schützt z.B. die Presse vor Zensur durch den Staat. Wo jedoch die Meinungsfreiheit aufhört und ab wann z.B. Satire diese Freiheiten überschreitet, ist nicht immer ganz eindeutig und für den Laien kaum zu beurteilen. Die Entscheidungen des Bundesverfassungsgerichts z.B. zeigen, dass das Einordnen von Aussagen nicht so leicht ist, wie es vorerst scheint
Mathematical Modelling and Simulation of Catalyst Deactivation for the Continuous Thermo-Catalytic Decomposition of Methane
No full textA clean energy future based on a hydrogen economy has been proposed as a feasible alternative to the current combustion of fossil fuels to reduce CO2 and other greenhouse gas (GHG) emissions. However, hydrogen’s “clean” reputation is questionable due to its main production method of steam methane reforming (SMR), which produces large quantities of CO2 emissions. To abide by recent international regulations, the production of hydrogen needs an immediate transition to low-emission production methods. A promising solution is the thermo-catalytic decomposition of methane (TCMD), which thermally decomposes methane into hydrogen gas and solid carbon without any direct GHG emissions. The problem with this process is that the catalyst deactivates quickly and therefore must be replaced periodically for sustained hydrogen yields. This results in high catalyst turnover costs, which is the main bottleneck in the successful commercialisation of this process. By developing a simplified model using the most commercially viable parameters and linking the turnover costs with the deactivation of the catalyst, this study aimed to accelerate the adoption of the TCMD process by better enabling companies to analyse the feasibility of their potential low-emission TCMD solutions.
The most commercially viable solution featured the use of a fluidised bed reactor (FBR) for continuous operation with an iron-based catalyst due to their low-cost. Catalyst regeneration was found to be ineffective and the best method for mitigating catalyst deactivation was the optimisation of the process conditions. A simplified mathematical model was then constructed to enable this adjustment to maximise the production of hydrogen and minimise the turnover costs. This model was based on the ideal continuous stirred tank reactor but incorporated the fluidising behaviour through several variables including the development of the novel “Fluidisation Factor”. An optimisation ratio was also developed to quantify the simulation results and obtain the optimal conditions.
The results showed that the ideal conditions for this process was at the highest temperature before the catalyst starts to sinter (≈950ºC) and at the maximum pressure. The largest catalyst particle size of 150 m and the maximum amount of catalyst was found to allow for higher fluidisation velocities and to delay the deactivation time respectively. The inlet gas velocity and the catalyst activity limit were found to be highly dependent on the hydrogen production rate and therefore due to the conditions used in this study the optimum inlet gas velocity was 10% of the fluidisation velocity range (and composed of pure methane), whilst the optimum activity limit was at 22% activity. Lastly, a comparison of the heating method found that controlled heating was more suitable than constant heating due to the stable temperatures during deactivation, which prevent catalyst sintering. Comparing the optimised results from this study with the SMR production method found that the estimated catalyst turnover costs were 10¢/kg H2 and 18¢/kg H2 respectively. This demonstrates that the simplified model developed in this work can better enable companies to optimise and assess the feasibility of their proposed TCMD solutions and help transition their hydrogen production processes to cleaner alternatives
18/2021 Erneute Verschiebung der Wahlen zu Gremien und Organen der Hochschule Rhein-Waal aufgrund der weiterhin ausstehenden BSI-Sicherheits-Rezertifizierung der POLYAS GmbH und Festsetzung des Wahltermins
No full text21/2021 Erste Änderungssatzung zur Prüfungsordnung vom 10.07.2019, amtliche Bekanntmachung Nr. 26/2020, für den Bachelorstudiengang Communication and Information Engineering der Fakultät Kommunikation und Umwelt der Hochschule Rhein-Waal
No full textAutomatisierte Tests oberflächenbezogener Geschäftslogik mit simulierten Benutzereingaben
No full textA lack of stability and reliability in user interfaces leads to user dissatisfaction. If this dissatisfaction is a repeating occurence users loose trust in the software and the company behind it. In the long run this leads to a migration from existing users to competitors and less new customers. To combat these effects companies have to ensure their user interfaces are stable and reliable. The Schleupen AG provides a browserbased user interface to its customers, which is split into a display layer running in the browser and a logic layer running on the server. In this thesis an automated solution for finding such problems in the logic layer was developed and applied to a selected subset of user interfaces. The solution was able to find multiple issues with most of them representing possible stability problems. This showed that automated testing of user interfaces for stability and reliability is possible and worthwhile
Über die Bedeutung von Online-Yoga-Angeboten während der COVID-19-Pandemie als gesundheitsförderndes Instrument
No full textDiese Masterarbeit untersucht die Bedeutung von Online-Yoga-Angeboten als gesundheitsförderndes Instrument unter besonderer Betrachtung der COVID-19-Pandemie. Bei Yoga handelt es sich um eine der ältesten philosophischen Lehren und Methoden, welche unter anderem durch Körperübungen in Verbindung mit kontrollierten Atemübungen die Einheit und Stärkung von Körper, Geist und Seele anstrebt (Schöps 2020, S. 6). Interventionen zur Bekämpfung von COVID-19 führen zu starken Einschränkungen des täglichen Lebens. Besonders Kontaktbeschränkungen, Ausgangssperren sowie Schließungen von Freizeit-, Kultur- und Bildungseinrichtungen führen, je länger diese aufrecht erhalten werden, zu einem deutlichen Anstieg der psychischen Belastungen. Aufgrund der Hygienevorschriften und Schließung von Sporteinrichtungen sind körperliche Bewegungen oder sportliche Aktivitäten meist auf die eigene Häuslichkeit beschränkt. Da das Praktizieren von Yoga in Präsenzkursen durch die viruseindämmenden Maßnahmen nicht mehr möglich ist, werden onlinebasierte Alternativen, wie beispielsweise Yoga-Apps, Videoübertragungen in Echtzeit oder Videos von Videoportalen stärker frequentiert und notwendig. Die Zielsetzung dieser Masterarbeit besteht darin, mit Hilfe einer Online-Umfrage die Forschungsfrage „Wie wirkt sich Online-Yoga in Zeiten von COVID-19 auf die Gesundheit aus?“ zu untersuchen. Die statistischen Ergebnisse zeigen mäßig bis starke psychische Belastungen aufgrund der COVID-19-Pandemie, welche in besonders hohem Maße die Belastungsfaktoren Antriebslosigkeit, Niedergeschlagenheit, Interessenlosigkeit sowie das Gefühl, keine Energie zu haben und Schlafstörungen umfassen. Das Praktizieren von Online-Yoga verhilft bezugnehmend auf diese Belastungsfaktoren zur Linderung und entfaltet insgesamt eine positive, gesundheitsfördernde Wirkung. Darüber hinaus stärkt die Online-Yoga-Praxis die individuellen Fähigkeiten sowie Strategien zur Anpassung und Bewältigung im Hinblick auf die viruseindämmenden Maßnahmen. Mit steigender Dauer und Häufigkeit der Online-Yoga-Praxis geht auch eine größere gesundheitsfördernde Wirkung einher. Außerdem zeichnet sich anhand der Ergebnisse ein gestärktes Gesundheitsbewusstsein ab. Diesbezüglich gilt ebenfalls, je länger Yoga praktiziert wird, desto häufiger liegt die Motivation in der Verbesserung der psychischen und körperlichen Gesundheit begründet. Die Wirkung des Online-Yoga wird als beruhigend, entspannungsfördernd und positiv im Hinblick auf die körperliche Fitness sowie Ausgeglichenheit beschrieben. Es lässt sich demnach schlussfolgern, dass die Inanspruchnahme von Online-Yoga-Interventionen insgesamt eine mindestens genauso effektive und gesundheitsfördernde Wirkung erzielt, wie das Praktizieren in Präsenz-Kursen, in welchen die Yogaübungen durch einen Yogalehrenden angeleitet werden.This master´s thesis investigates the significance of online yoga offerings as a health-promoting measure with special regard to the COVID-19 pandemic. Yoga is one of the oldest philosophical teachings and methods, which strives for the unity and strengthening of body, mind and spirit through physical exercises in conjunction with controlled breathing exercises (Schöps 2020, p.6). Interventions to combat COVID-19 lead to severe restrictions on daily life. In particular, contact restrictions, curfews and closures of recreational, cultural and educational facilities increase psychological strain the longer they are maintained. Due to hygiene regulations and closure of sports facilities, physical exercises or sports activities are usually limited to one´s own home. Since practicing yoga in face-to-face classes is no longer possible due to virus-containment measures, online-based alternatives, such as yoga-apps, real-time video broadcasts, or videos from video portals, are necessary and becoming more frequented. The objective of this master´s thesis is to use an online survey to investigate the research question, ´What is the impact of online yoga on health in the era of COVID-19?`. The statistical results show moderate to severe psychological strain due to the COVID-19 pandemic, which particularly includes listlessness, dejection, lack of interest, lack of energy and insomnia. The study shows that practicing online yoga helps to alleviate these mental stress factors, having a positive, health promoting overall effect. Furthermore, the online yoga practice strengthens individual skills and strategies for adaption and coping with virus-control measures. With increasing duration and frequency of online yoga practice, comes greater health benefits, as several studies have stated. Moreover, the results indicate a strengthening of health awareness. Referring to this, the longer yoga is practiced, the more often the motivation is based on improving mental and physical health. The effect of online yoga is described as calming, relaxing and positive in terms of physical fitness as well as level-headedness. Concluding ultimately, the right utilization of online yoga interventions is started to be effective and health-promoting, just as practicing in face-to-face classes guided by a yoga teacher is
Simulation of an OLOID Agitator with OpenFOAM for use in Bioprocesses
No full textOloids are said to be very energy efficient stirrers, generating low shear rates while providing good mixing for small-to-medium-sized water bodies, which would make them optimal for decreasing energy cost in large installations as well as protecting shear-sensitive microorganisms. Yet oloids are relatively obscure and there are few works dealing with detailed analysis of their flow profile and comparison against standard stirrers. This work tries to add to this topic. In this thesis the potential of deploying oloid stirrers in bioprocesses and wastewater treatment in general is to be probed by computational fluid simulation and compared against a propeller and a Smith turbine (modification of a Rushton turbine). Parameters of interest are flow and pressure profile as well as shear stress.
The results show that oloids have much lower shear at their surface compared to both propeller and Smith turbine. The flow is pulsating and in three dimensions, and while the results need verification, it seems like the oloid is well usable for agitation in ungassed bioprocesses, because it can mix a small water body at much lower stirrer speeds than rotating impellers. The application in an actively gassed vessel and whether it is usable for active gas dispersion has not been analysed. Based on data generated by others, the oloid can also be used efficiently as surface aerator in natural open water bodies
The Root and Tuber Crop Value Chain in Cameroon: An Analysis of its Structure and Performance
No full textThe aim of this study was to analyse the structure and performance of the root and tuber crop value chain in Cameroon. The study area included the North-west, Southwest, Littoral, Central and West regions of Cameroon. Data was collected through surveys and interviews with key informants and between the months of March and August 2021. A sample of 457 Value chain actors com-prising 163 farmers, 105 traders, 70 processors and 119 consumers was se-lected through a simple random sampling procedure. Secondary data was col-lected from published studies and from some officials of the Ministry of Agricul-ture. Data analysis was done using Microsoft Excel. Social Network Analysis, Functional institutional Analysis and the French Systematic method were used to analyse the structure of the value chain. Demographic and production char-acteristics were analysed by means of descriptive statistics. Profitability analy-sis was used to determine the profit margins of value chain actors. The results of the study revealed that 47% of farmers were males and 53% were females and that 77.1 % of traders and 65.3% of processors had attained at least sec-ondary level of education. Farm sizes ranged from 0.4 – 3 hectares and 81% them practiced mixed cropping. The shortest marketing (from farmers – con-sumer) was the most used channel. The calculated average yield of cassava was 9.25 t/ha and that for sweet potatoes was 7.65 t/ha. Pre-harvest loss stood at 4.7% and the total post-harvest loss was 17.6% for sweet potatoes and 5.8% for cassava. The gross profit per hectare for cassava farmers was 63,069 FCFA and for sweet potato farmers it was 697,134 FCFA. The monthly gross profits for cassava traders (469,342 FCFA) were greater than that of processors (212,587 FCFA). The overall performance of the value chain was considered low due to poor record keeping, low profit margins, high percentage of post-harvest losses, few number of processed products, and poor chain governanc