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Modelling and dimensioning of circular food production systems fed by geothermal energy: Aquaponics
No full textThe ongoing global push for sustainable food production has motivated both the greenhouse horticulture and aquaculture sectors to explore the potential of geothermal energy for heating as an alternative to fossil fuels. Greenhouses and fish farms experience distinct heat demand fluctuations throughout the year and therefore do not make consistent use of geothermal wells. Geothermal wells on the other hand, need to operate close to full capacity year-round to be profitable. An opportunity to improve the economic feasibility of geothermal heating infrastructure is to use circular food production systems, such as aquaponics, which can be operated as a thermal treatment network in order to increase heat extraction from geothermal well installations. The EU funded GEOFOOD project aims to analyze in detail how to optimise the design and operation of geothermal aquaponic facilities. To quantify the potential benefits, a predictive model was developed which simulates the heat balances present throughout the aquaponic-based thermal treatment network. The inputs include the relevant climate parameters of the location, the type of greenhouse/building for both facilities including climate control equipment, as well as crop and fish species. For a scenario considering a 5-ha Dutch tomato greenhouse it is found that geothermal heat extraction can be increased with 31% by combining it with an indoor pike-perch fish farm of 6544 m2, without the need of alternative energy sources during peak demands.</p
Multi-stakeholder participation for sustainable delta management: a challenge of the socio-technical transformation in the management practices in Bangladesh
No full textIn Bangladesh, participation discourse has officially become part of the objectives of the government and international agencies for water management projects since the mid-1990s. At the same historical timeframe, originating from indigenous knowledges Tidal River Management (TRM) has been formalized as a less structural and more natural management intervention to prevent the severe water-logging in the South-west region in the Bangladesh delta. It theoretically constituted a form of participation in the delta management system involving local community groups with government and management authorities. However, multi-stakeholder participation is still very challenging in practices. Even community management approaches are not sustained in delta management practices in Bangladesh. In this research, a socio-technical transformation is defined through a participatory research in the south-west coastal area having both qualitative and quantitative evaluation of changes in the delta management system brought about by TRM practices. This article also analyses the current problems besetting organized community participation in existing management practices and suggests the ways of developing effective multi-stakeholder processes (MSPs) with respect to sustainable management goal in deltas.</p
Review: Rumen sensors: Data and interpretation for key rumen metabolic processes
No full textRumen sensors provide specific information to help understand rumen functioning in relation to health disorders and to assist in decision-making for farm management. This review focuses on the use of rumen sensors to measure ruminal pH and discusses variation in pH in both time and location, pH-associated disorders and data analysis methods to summarize and interpret rumen pH data. Discussion on the use of rumen sensors to measure redox potential as an indication of the fermentation processes is also included. Acids may accumulate and reduce ruminal pH if acid removal from the rumen and rumen buffering cannot keep pace with their production. The complexity of the factors involved, combined with the interactions between the rumen and the host that ultimately determine ruminal pH, results in large variation among animals in their pH response to dietary or other changes. Although ruminal pH and pH dynamics only partially explain the typical symptoms of acidosis, it remains a main indicator and may assist to optimize rumen function. Rumen pH sensors allow continuous monitoring of pH and of diurnal variation in pH in individual animals. Substantial drift of non-retrievable rumen pH sensors, and the difficulty to calibrate these sensors, limits their application. Significant within-day variation in ruminal pH is frequently observed, and large distinct differences in pH between locations in the rumen occur. The magnitude of pH differences between locations appears to be diet dependent. Universal application of fixed conversion factors to correct for absolute pH differences between locations should be avoided. Rumen sensors provide high-resolution kinetics of pH and a vast amount of data. Commonly reported pH characteristics include mean and minimum pH, but these do not properly reflect severity of pH depression. The area under the pH × time curve integrates both duration and extent of pH depression. The use of this characteristic, as well as summarizing parameters obtained from fitting equations to cumulative pH data, is recommended to identify pH variation in relation to acidosis. Some rumen sensors can also measure the redox potential. This measurement helps to understand rumen functioning, as the redox potential of rumen fluid directly reflects the microbial intracellular redox balance status and impacts fermentative activity of rumen microorganisms. Taken together, proper assessment and interpretation of data generated by rumen sensors requires consideration of their limitations under various conditions.</p
Responses of ecosystem services to natural and anthropogenic forcings: A spatial regression based assessment in the world's largest mangrove ecosystem
No full textMost of the Earth's Ecosystem Services (ESs) have experienced a decreasing trend in the last few decades, primarily due to increasing human dominance in the natural environment. Identification and categorization of factors that affect the provision of ESs from global to local scales are challenging. This study makes an effort to identify the key driving factors and examine their effects on different ESs in the Sundarbans region, India. We carry out the analysis following five successive steps: (1) quantifying biophysical and economic values of ESs using three valuation approaches; (2) identifying six major driving forces on ESs; (3) categorizing principal data components with dimensionality reduction; (4) constructing multivariate regression models with variance partitioning; (5) implementing six spatial regression models to examine the causal effects of natural and anthropogenic forcings on ESs. Results show that climatic factors, biophysical factors, and environmental stressors significantly affect the ESs. Among the six driving factors, climate factors are highly associated with the ESs variation and explain the maximum model variances (R2 = 0.75–0.81). Socioeconomic (R2 = 0.44–0.66) and development (R2 = 27–0.44) factors have weak to moderate effects on the ESs. Furthermore, the joint effects of the driving factors are much higher than their individual effects. Among the six spatial regression models, Geographical Weighted Regression (GWR) performs the most accurately and explains the maximum model variances. The proposed hybrid valuation method aggregates biophysical and economic estimates of ESs and addresses methodological biases existing in the valuation process. The presented framework can be generalized and applied to other ecosystems at different scales. The outcome of this study could be a reference for decision-makers, planners, land administrators in formulating a suitable action plan and adopting relevant management practices to improve the overall socio-ecological status of the region.</p
A thermophilic C-phycocyanin with unprecedented biophysical and biochemical properties
No full textC-phycoyanins are abundant light-harvesting pigments which have an important role in the energy transfer cascade of photosystems in prokaryotic cyanobacteria and eukaryotic red algae. These proteins have important biotechnological applications, since they can be used in food, cosmetics, nutraceutical, pharmaceutical industries and in biomedical research. Here, C-phycocyanin from the extremophilic red alga Galdieria phlegrea (GpPC) has been purified and characterized from a biophysical point of view by SDS-PAGE, mass spectrometry, UV–Vis absorption spectroscopy, circular dichroism and intrinsic fluorescence. Stability against pH variations, addition of the oxidizing agent hydrogen peroxide and the effects of temperature have been also investigated, together with its in cell antioxidant potential and antitumor activity. GpPC is stable under different pHs and unfolds at a temperature higher than 80 °C within the pH range 5.0–7.0. Its fluorescence spectra present a maximum at 650 nm, when excited at 589 nm. The protein exerts interesting in cell antioxidant properties even after high temperature treatments, like the pasteurization process, and is cytotoxic for A431 and SVT2 cancer cells, whereas it is not toxic for non-malignant cells. Our results assist in the development of C-phycocyanin as a multitasking protein, to be used in the food industry, as antioxidant and anticancer agent.</p
Automated reasoning framework for traceability management of system of systems
No full textAn important aspect in system of systems (SoS) is the realization of the capabilities in different systems that work together. Identifying and locating these capabilities are important to orchestrate the overall activities and hereby to achieve the overall goal of the SoS. System elements and capabilities in SoS however, are rarely stable and need to evolve in different ways and different times in accordance with the changing requirements. To manage the SoS and cope with its evolution it is necessary that the dependency links to the capabilities and the system elements can be easily traced. Several approaches have been proposed to model traceability and reason about these by extending a predetermined set of possible trace links with fixed semantics. However, for the context of SoS a fixed traceability model with fixed traceability semantics is limited to consider the various different and changing scenarios. In this article, we first present the different traceability requirements for managing traceability in the context of SoS. Subsequently, we present the metamodel and the corresponding domain specific language to support modeling traceability and traceability analysis approaches within the evolving SoS context. Further, we provide the tool support for automated reasoning of traceability of SoS capabilities and system elements. We illustrate and discuss the approach for the application to a smart city SoS.</p
Congresverslag deel 2: Meat for diversifying markets
No full textDe wereld verandert. De digitale revolutie, een wereldwijde focus op duurzaamheid, de zorg om het milieu: ze beïnvloeden ook de voedings- en vleesindustrie. Thema’s als het borgen van de voedselveiligheid, het voorkomen van voedselverspilling en issues rondom de eiwittransitie roepen talloze vragen op. Voor wetenschappers wereldwijd een uitgangspunt voor vele onderzoeken en studies. Het resultaat: vernieuwende inzichten en mooie innovaties
Measurement of length distribution of beta-lactoglobulin fibrils by multiwavelength analytical ultracentrifugation
Get PDFThe whey protein beta-lactoglobulin is the building block of amyloid fibrils which exhibit a great potential in various applications. These include stabilization of gels or emulsions. During biotechnological processing, high shear forces lead to fragmentation of fibrils and therefore to smaller fibril lengths. To provide insight into such processes, pure straight amyloid fibril dispersions (prepared at pH 2) were produced and sheared using the rotor stator setup of an Ultra Turrax. In the first part of this work, the sedimentation properties of fragmented amyloid fibrils sheared at different stress levels were analyzed with mulitwavelength analytical ultracentrifugation (AUC). Sedimentation data analysis was carried out with the boundary condition that fragmented fibrils were of cylindrical shape, for which frictional properties are known. These results were compared with complementary atomic force microscopy (AFM) measurements. We demonstrate how the sedimentation coefficient distribution from AUC experiments is influenced by the underlying length and diameter distribution of amyloid fibrils. In the second part of this work, we show how to correlate the fibril size reduction kinetics with the applied rotor revolution and the resulting energy density, respectively, using modal values of the sedimentation coefficients obtained from AUC. Remarkably, the determined scaling laws for the size reduction are in agreement with the results for other material systems, such as emulsification processes or the size reduction of graphene oxide sheets.</p
Flavoenzyme-mediated regioselective aromatic hydroxylation with coenzyme biomimetics
No full textRegioselective aromatic hydroxylation is desirable for the production of valuable compounds. External flavin‐containing monooxygenases activate and selectively incorporate an oxygen atom in phenolic compounds through flavin reduction by the nicotinamide adenine dinucleotide coenzyme and subsequent reaction with molecular oxygen. This study provides the proof of principle of flavoenzyme‐catalyzed selective aromatic hydroxylation with coenzyme biomimetics. The carbamoylmethyl‐substituted biomimetic in particular affords full conversion in less than two hours for the selective hydroxylation of 5 mM 3‐ and 4‐hydroxybenzoates, displaying similar rates as with NADH, achieving a 10 mM/h enzymatic conversion of the medicinal product gentisate. This biomimetic appears to generate less uncoupling of hydroxylation that typically leads to undesired hydrogen peroxide. Therefore, we show these flavoenzymes have the potential to be applied in combination with biomimetics