Grid inductance estimation by reactive power perturbation for sensor-less scheme based on virtual flux

Use of renewable energy sources is raising for grid connected systems, for which higher power quality requirements are being issued. Monitoring the grid impedance ensure stable operation of the controller and proper connection and disconnection from the grid. Thus it is vital to know the value of grid or transformer distributed impedance in given time, instead assuming a constant value in controller. To overcome this problem an identification method based on perturbation of reactive power is proposed. The normally inductive character of the grid used together with synchronous frame current controller have cross coupling terms which are used in analysis. This method is suitable for use with virtual flux oriented control. It uses two current sensors and one dc link voltage sensor. Method enables maintain unity power factor not only at PCC but also further into the grid, including lines and transformer leakage inductance.reviewe

Seaweed as food – Attitudes and preferences among Swedish consumers. A pilot study

The demand for vegetarian food is increasing and seaweeds are promising raw materials with interesting nutritional and sensory profiles. The aim of this study was to investigate the attitudes and preferences of Swedish consumers regarding seaweed as food and study differences and similarities between different consumer groups. Data from 120 adult consumers showed an overall positive attitude. More young men than women preferred seaweeds in snack products and fast food. Products containing seaweed should preferably be bought in a food store and eaten at home or in a restaurant. The most popular serving alternatives were in snacks, bread and dishes

How Leadership Dynamics Differs in High- and Low- Performing Firms in a Sustainable Innovation Context : A Qualitative Case Study from the Health Tech Sector

Leadership is essential to achieving sustainable innovation, yet research to date on innovation tends to focus on individual leaders, while innovation leadership appears to be a collective and dynamic process. While extant literature has examined collective leadership dynamics research regarding how collective leadership dynamics play out over time in sustainable innovative firms over time is nascent. This thesis is bridging the gap in the literature by examining the leadership dynamics in sustainable innovation companies. Specifically, to explore these dynamics, we conduct an explorative multi-case qualitative study in the health tech sector interviewing leaders in five companies in total, three high-performing and two lowperforming companies. The findings overall reveal key differences in high- and lowperforming firms. First, collective leadership dynamics varies along two dimensions, changeable roles, and fluid contributions. Second, these dynamics along these two dimensions differ through three phases, the initial (1), investment (2), and launching phases (3). While high- and low-performing companies have similar dynamics in the initial phase 1) with collective processes and interchangeable roles, differences in dynamics appear in the investment (2) and launching phases (3). While an influx of tension from new individuals is affecting both the high- and low-performing companies, differences appear in how they handle such tensions. In the second and third phase, the high-performing companies manage to utilize tension and at the same time build a more structured company where competency and delegation are critical. Low-performing companies experience the tension as a negative disturbance, where collective leadership appears to coincide with the CEO´s role in the company weakens. The findings contribute to understanding the relationship between the collective leadership, along two dynamic dimensions, and how this relates to growth in a sustainable innovation context.nhhma

Production of protein extracts from Swedish red, green, and brown seaweeds, Porphyra umbilicalis Kützing, Ulva lactuca Linnaeus, and Saccharina latissima (Linnaeus) J. V. Lamouroux using three different methods

peer-reviewedThe demand for vegetable proteins increases globally and seaweeds are considered novel and promising protein sources. However, the tough polysaccharide-rich cell walls and the abundance of polyphenols reduce the extractability and digestibility of seaweed proteins. Therefore, food grade, scalable, and environmentally friendly protein extraction techniques are required. To date, little work has been carried out on developing such methods taking into consideration the structural differences between seaweed species. In this work, three different protein extraction methods were applied to three Swedish seaweeds (Porphyra umbilicalis, Ulva lactuca, and Saccharina latissima). These methods included (I) a traditional method using sonication in water and subsequent ammonium sulfate-induced protein precipitation, (II) the pH-shift protein extraction method using alkaline protein solubilization followed by isoelectric precipitation, and (III) the accelerated solvent extraction (ASE®) method where proteins are extracted after pre-removal of lipids and phlorotannins. The highest protein yields were achieved using the pH-shift method applied to P. umbilicalis (22.6 ± 7.3%) and S. latissima (25.1 ± 0.9%). The traditional method resulted in the greatest protein yield when applied to U. lactuca (19.6 ± 0.8%). However, the protein concentration in the produced extracts was highest for all three species using the pH-shift method (71.0 ± 3.7%, 51.2 ± 2.1%, and 40.7 ± 0.5% for P. umbilicalis, U. lactuca, and S. latissima, respectively). In addition, the pH-shift method was found to concentrate the fatty acids in U. lactuca and S. latissima by 2.2 and 1.6 times, respectively. The pH-shift method can therefore be considered a promising strategy for producing seaweed protein ingredients for use in food and feed

In vitro bioaccessibility of proteins and lipids of pH-shift processed Nannochloropsis oculata microalga

The pH-shift process fractionates biomass into soluble proteins and insoluble fractions, followed by precipitation and recovery of the solubilized proteins. Nannochloropsis oculata in seawater was subjected to the pH-shift process, followed by digestion of various intermediates and product fractions of the process, using the Infogest in vitro digestion model (Minekus et al., 2014) with added gastric lipase. As measures for protein and lipid accessibility, degrees of protein hydrolysis and fatty acid liberation were assessed post-digestion and compared to the amounts of peptide bonds and total fatty acids present in the raw materials. Results showed that neither proteins nor lipids of intact Nannochloropsis cells were accessible to the mammalian digestive enzymes used in the digestion model. Cell disruption, and to a lesser extent, further pH-shift processing with protein solubilisation at pH 7 or pH 10, increased the accessibility of lipids. For proteins, differences amongst the pH-shift processed materials were non-significant, though pre-freezing the product prior to digestion increased the accessibility from 32% to 47%. For fatty acids, pH-shift process-products gave rise to 43% to 52% lipolysis, with higher lipolysis for products solubilised at pH 10 as opposed to pH 7. Our results indicate the importance of processing to produce an algal product that has beneficial nutritional properties when applied as food or feed

Controlling hemoglobin-mediated lipid oxidation in herring (Clupea harengus) co-products via incubation or dipping in a recyclable antioxidant solution

Applying value-adding techniques to fish co-products is rendered difficult due to their high susceptibility to hemoglobin (Hb)-mediated lipid oxidation. In this study, we investigated a dipping technology with a solution containing Duralox MANC 213- a mixture of rosemary extract, ascorbic acid, tocopherols and citric acid – to control lipid oxidation during storage at 0 \ub0C and 20 \ub0C. The possibilities to re-use the antioxidant solution was also analyzed, along with studies on the link between Duralox MANC and Hb-form. Dipping in Duralox MANC largely increased the oxidation lag phase; from <0.5 to >3.5 d at 20 \ub0C, and from <1 d to >11 d at 0 \ub0C. Even after re-use of the solution up to 10 times, lipid oxidation was completely inhibited at 0 \ub0C. Duralox MANC could prevent auto-oxidation and hemin loss of herring Hb; which are suggested as the main mechanisms behind the observed stabilization of herring co-products against lipid oxidation

Application of Filtration to Recover Solubilized Proteins During pH-Shift Processing of Blue Whiting (Micromesistius poutassou); Effects on Protein Yield and Qualities of Protein Isolates

Previous studies of the pH-shift protein isolation process have shown that substantial amounts of solubilized proteins can be trapped in the sediments formed in the first centrifugation step of this process. As a strategy to improve the protein yield during pH-shift processing, the aim of this study was to evaluate how filtration as an alternative to centrifugation in the first separation step of pH-shift processing of blue whiting affected proteins yield and protein isolate characteristics (basic composition, polypeptide profiles, surimi gel quality and color attributes). The study comprised both the acid and alkaline versions of the method, and also fresh as well as frozen fish raw material. Results showed that the replacement of centrifugation with filtration substantially improved the protein yield by from about 38% to 62%, but also reduced the removal of lipid. There were no significant effects on gel quality. Protein isolates from fresh raw material were about 5 % whiter and frozen raw materials about 3% whiter with centrifugation as compared to filtration in the pHshift process. For surimi from fresh raw material centrifugation gave about 2 % whiter gels, while the gels from frozen raw material were about 3% whiter for filtered compared to centrifuged material. The whitest isolates and gels were obtained with acid processing of fresh blue whiting. Slight proteolytic breakdown resulting in fragments of 83 and 152 kDa was however noted with the acid process, especially when centrifugation was used

Effect of antioxidants on lipid oxidation in herring (Clupea harengus) co-product silage during its production, heat-treatment and storage

Provided high product quality, ensilaging can be used to valorize fish filleting co-products into a silage suitable for food applications. However, a documented challenge for products from hemoglobin-rich fish raw materials is the high susceptibility to lipid oxidation, calling for stabilization by antioxidants. In a comparison among different rosemary-containing antioxidants and isoascorbic acid, we here found that the commercial mixture Duralox MANC-213 (MANC) provided the best protection against peroxide value and 2-thiobarbituric acid reactive substances (TBARS) development during ensilaging of herring filleting co-products (0–7\ua0days, 22\ua0\ub0C), and also during subsequent heat-treatment (30\ua0min, 85\ua0\ub0C). Increasing MANC concentration from 0.25 and 0.75 to 1.25% lowered TBARS values from 43.53 and 25.12 to 18.04 \ub5mole TBARS/Kg silage, respectively, after 7\ua0days of ensilaging. During storage at 4\ua0\ub0C/22\ua0\ub0C in presence of MANC, 1.25% provided the highest protection with 87–90% and 66–73% lower TBARS, at 4\ua0\ub0C and 22\ua0\ub0C, respectively, at 6\ua0months compared to the controls. At this time point, heat-treated silages had lower protein degree of hydrolysis and free amino acids values than the non-heat-treated one. Regardless of antioxidant addition, total volatile basic nitrogen (TVB-N) formation still increased during the storage, but, overall, TVB-N values in silages were below the acceptable limit of 30\ua0mg TVB-N/100\ua0g fish for human consumption. Together with lipid oxidation data, this suggests that herring silage produced in presence of antioxidants can be used both for high-quality feed and food applications

Effect of antioxidants on lipid oxidation in herring (Clupea harengus) co-product silage during its production, heat-treatment and storage

Provided high product quality, ensilaging can be used to valorize fish filleting co-products into a silage suitable for food applications. However, a documented challenge for products from hemoglobin-rich fish raw materials is the high susceptibility to lipid oxidation, calling for stabilization by antioxidants. In a comparison among different rosemary-containing antioxidants and isoascorbic acid, we here found that the commercial mixture Duralox MANC-213 (MANC) provided the best protection against peroxide value and 2-thiobarbituric acid reactive substances (TBARS) development during ensilaging of herring filleting co-products (0-7 days, 22 degrees C), and also during subsequent heat-treatment (30 min, 85 degrees C). Increasing MANC concentration from 0.25 and 0.75 to 1.25% lowered TBARS values from 43.53 and 25.12 to 18.04 mu mole TBARS/Kg silage, respectively, after 7 days of ensilaging. During storage at 4 degrees C/22 degrees C in presence of MANC, 1.25% provided the highest protection with 87-90% and 66-73% lower TBARS, at 4 degrees C and 22 degrees C, respectively, at 6 months compared to the controls. At this time point, heat-treated silages had lower protein degree of hydrolysis and free amino acids values than the non-heat-treated one. Regardless of antioxidant addition, total volatile basic nitrogen (TVB-N) formation still increased during the storage, but, overall, TVB-N values in silages were below the acceptable limit of 30 mg TVB-N/100 g fish for human consumption. Together with lipid oxidation data, this suggest that herring silage produced in presence of antioxidants can be used both for high quality feed and food applications