34 research outputs found

    Thickness-dependent thermal properties of amorphous insulating thin films measured by photoreflectance microscopy

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    In this work, we report on the measurement of the thermal conductivity of thin insulating films of SiO2 obtained by thermal oxidation, and Al2O3 grown by atomic layer deposition (ALD), both on Si wafers. We used photoreflectance microscopy to determine the thermal properties of the films as a function of thickness in the 2 nm to 1000 nm range. The effective thermal conductivity of the Al2O3 layer is shown to decrease with thickness down to 70% for the thinnest layers. The data were analyzed upon considering that the change in the effective thermal conductivity corresponds to an intrinsic thermal conductivity associated to an additional interfacial thermal resistance. The intrinsic conductivity and interfacial thermal resistance of SiO2 were found to be equal to 0.95 W/m·K and 5.1 × 10− 9 m2K/W respectively; those of Al2O3 were found to be 1.56 W/m·K and 4.3 × 10− 9 m2K/W

    Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology

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    Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p lt 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p lt 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum

    Fruiting-body-base flour from an oyster mushroom – a waste source of antioxidative flour for developing potential functional cookies and steamed-bun

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    In a commercial oyster mushroom farm, fruiting body base (FBB) was not harvested compared to the common cap and stem of the fruiting body parts, and thus remained as waste. In the present study, unused FBB was powdered and subjected to proximate analysis as floured FBB (FFBB). FFBB was found to contain 71.2% carbohydrate, 8.93% moisture, 7.18% fibre, 5.72% ash, 5.57% protein, and 1.4% fat, while raw-FBB (RFBB) contained 7.57% carbohydrate, 84.4% moisture, 5.17% fibre, 5.72% ash, 1.54% protein, and 0.85% fat. The high carbohydrate content of FFBB was subjected to hot-water extraction and yielded 7.40 g of FFBB polysaccharide (FFBBP). Total phenolic content (TPC) of FFBBP contained 1.80 mg gallic acid equivalents (GAE)/g, exhibiting the reducing activity of 1.74 mM Fe(II)/g by ferric reducing antioxidant power assay, and reduced the stable 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical forms at IC50 of 25.08 mg/mL, which was comparable with other parts of oyster mushroom species. Different percentages of FFBB mixtures were utilized in the production of cookies (10% and 20%) and steamed buns (10%, 20% and 30%). Thirty-seven panellists were selected for sensory testing, which showed that 10% of FFBB in a steamed bun was more acceptable than 30% of FFBB, while the overall acceptance of cookies with 10% FBB was insignificant (p > 0.05) but 20% FFBB in cookies was significantly different from control (p < 0.05). This study indicates that potential value of FFBB as an economical antioxidative flour in the development of functional foods

    Performance of wild-serbian ganoderma lucidum mycelium in treating synthetic sewage loading using batch bioreactor

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    The fluctuation of domestic wastewater characteristic inhibits the current conventional microbial-based treatment. The bioremediation fungi has received attention and reported to be an effective alternative to treat industrial wastewater. Similar efficient performance is envisaged for domestic wastewater whereby assessed performance of fungi for varying carbon-to-nitrogen ratios in domestic wastewater is crucial. Thus, the performance of pre-grown wild-Serbian Ganoderma lucidum mycelial pellets (GLMPs) was evaluated on four different synthetic domestic wastewaters under different conditions of initial pH (pH 4, 5, and 7) and chemical oxygen demand (COD) to nitrogen (COD/N) ratio of 3.6:1, 7.1:1, 14.2:1, and 17.8:1 (C3.6N1, C7.1N1, C14.2N1, and C17.8N1). The COD/N ratios with a constant concentration of ammonia–nitrogen (NH3–N) were chosen on the basis of the urban domestic wastewater characteristics sampled at the inlet basin of a sewage treatment plant (STP). The parameters of pH, COD, and NH3–N were measured periodically during the experiment. The wild-Serbian GLMPs efficiently removed the pollutants from the synthetic sewage. The COD/N ratio of C17.8N1 wastewater had the best COD and NH3–N removal, as compared to the lower COD/N ratio, and the shortest treatment time was obtained in an acidic environment at pH 4. The highest percentage for COD and NH3–N removal achieved was 96.0% and 93.2%, respectively. The results proved that the mycelium of GLMP has high potential in treating domestic wastewater, particularly at high organic content as a naturally sustainable bioremediation system

    Evaluation of commercial soy sauce koji strains of Aspergillus oryzae for γ-aminobutyric acid (GABA) production

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    In this study, four selected commercial strains of Aspergillus oryzae were collected from soy sauce koji. These A. oryzae strains designated as NSK, NSZ, NSJ and NST shared similar morphological characteristics with the reference strain (A. oryzae FRR 1675) which confirmed them as A. oryzae species. They were further evaluated for their ability to produce γ-aminobutyric acid (GABA) by cultivating the spore suspension in a broth medium containing 0.4 % (w/v) of glutamic acid as a substrate for GABA production. The results showed that these strains were capable of producing GABA; however, the concentrations differed significantly (P < 0.05) among themselves. Based on the A. oryzae strains, highest GABA concentration was obtained from NSK (194 mg/L) followed by NSZ (63 mg/L), NSJ (51.53 mg/L) and NST (31.66 mg/L). Therefore, A. oryzae NSK was characterized and the sequence was found to be similar to A. oryzae and A. flavus with 99 % similarity. The evolutionary distance (K nuc) between sequences of identical fungal species was calculated and a phylogenetic tree prepared from the K nuc data showed that the isolate belonged to the A. oryzae species. This finding may allow the development of GABA-rich ingredients using A. oryzae NSK as a starter culture for soy sauce production

    Position Paper on Water, Energy, Food and Ecosystem (WEFE) Nexus and Sustainable development Goals (SDGs)

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    The EU and the international community is realising that the Water, Energy, Food and Ecosystem components are interlinked and require a joint planning in order to meet the daunting global challenges related to Water, Energy and Food security and maintaining the ecosystem health and in this way, reach the SDGs. If not dealt with, the world will not be able to meet the demand for water, energy and food in a not too far future and, in any case, in a not sustainable way. The strain on the ecosystems resulting from unsustainable single-sector planning will lead to increasing poverty, inequality and instability. The Nexus approach is fully aligned with and supportive of the EU Consensus on Development. Key elements of the Consensus will require collaborative efforts across sectors in ways that can be supported/implemented by a Nexus approach. In this way, transparent and accountable decision-making, involving the civil society is key and common to the European Consensus on Development and the Nexus approach. The Nexus approach will support the implementation of the SDG in particular SDG 2 (Food), SDG 6 (Water) and SDG 7 (Energy), but most SDGs have elements that link to food, water and energy in one or other way, and will benefit from a Nexus approach. The SDGs are designed to be cross-cutting and be implemented together, which is also reflected in a WEFE Nexus approach. A Nexus approach offers a sustainable way of addressing the effects of Climate Change and increase resilience. The WEFE Nexus has in it the main drivers of climate change (water, energy and food security) and the main affected sectors (water and the environment). Decisions around policy, infrastructure, … developed based on the WEFE Nexus assessments will be suitable as elements of climate change mitigation and adaptation. In fact, it is difficult to imagine solutions to the climate change issue that are not built on a form of Nexus approach. The Nexus approach is being implemented around the world, as examples in the literature demonstrate. These examples together with more examples from EU and member state development cooperation will help build experience that can be consolidated and become an important contribution to a Toolkit for WEFE Nexus Implementation. From the expert discussions, it appears that because of the novelty of the approach, a Toolkit will be an important element in getting the Nexus approach widely used. This should build on experiences from practical examples of NEXUS projects or similar inter-sectorial collaboration projects; and, there are already policy, regulation and practical experience to allow institutions and countries to start applying the Nexus concept.JRC.D.2-Water and Marine Resource

    Multi criteria decision making to optimize the best runoff control measures for the Haditha Dam Reservoir, Iraq

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    In Iraq, the two dominating surface water sources are Tigris and Euphrates Rivers in which some dams constructed on both of them forming reservoirs. The Haditha Dam reservoir is one of the most essential sources of drinking, irrigation, flood control and hydropower generation in Anbar State, Western Iraq. Besides, the reservoir is a unique habitat with a wide spectrum of biodiversity. The objective of this study is to investigate and monitor the water quality in Haditha Dam reservoir and introduce Multi Criteria Analysis (MCA) as a means to highlight the best runoff control measures depending on selected criteria and criteria weights. Experts were interviewed for the selection of criteria and for the assignment of the weight factor and scores. Four criteria from three categories such as technical, economic and environmental aspects were selected. Results from this study indicated that a the difference in TSS and Turbidity between the dry and wet seasons necessitates the installation of runoff control measures. It was found that the soil binders, sediment basin and diversion channel are the best alternatives for controlling erosion, sediment and drainage respectively. The sensitivity analysis showed very strong decisions made by the experts for the technical, economic and environmental criteria.Validerad;2020;Nivå 1;2020-10-19 (alebob)</p

    Measurement of phonon damping by nanostructures

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    International audienceThe understanding of phonon lifetime and scattering rates is attracting an increasing interest due to the major role of phonon in thermal and electrical conductivity which are key properties for technological applications. The infrared complex dielectric function of a crystal is determined by the harmonic characteristics of the phonon together with the intrinsic and extrinsic phonon scattering rates. In order to investigate the interplay between the phonon intrinsic scattering and the scattering of the phonon by a nanostructured surface, infrared reflectivity measurements from SiC nano-pyramids on SiC substrate have been analysed using a Kramers-Kronig conversion technique to deduce the infrared complex dielectric function. Then, the real and imaginary parts of the dielectric function were fitted simultaneously by using a theoretical model for the dielectric constant that considers frequency-dependent phonon damping at the center of the Brillouin zone. It has been found that surface nanostructuring strongly enhances the overall scattering rate of the phonon at the Brillouin zone center
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