199 research outputs found

    Product and Packaging Innovation: Attitudes, Behaviours, and Strategies for Sustainable Packaging

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    The report presents findings of a large consumer survey on packaging, environmental issues and the media, conducted by Dr Martina Topic, Ben Mitchell and Olga Munroe. The survey was conducted on a representative sample of 1000 respondents, and forms a backbone of the future research and research outputs currently being prepared. This report has been distributed to the clients of the Retail Institute and will be presented at the Annual Retail Institute conference in September 2018

    Spontaneous breaking of spatial and spin symmetry in spinor condensates

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    Parametric amplification of quantum fluctuations constitutes a fundamental mechanism for spontaneous symmetry breaking. In our experiments, a spinor condensate acts as a parametric amplifier of spin modes, resulting in a twofold spontaneous breaking of spatial and spin symmetry in the amplified clouds. Our experiments permit a precise analysis of the amplification in specific spatial Bessel-like modes, allowing for the detailed understanding of the double symmetry breaking. On resonances that create vortex-antivortex superpositions, we show that the cylindrical spatial symmetry is spontaneously broken, but phase squeezing prevents spin-symmetry breaking. If, however, nondegenerate spin modes contribute to the amplification, quantum interferences lead to spin-dependent density profiles and hence spontaneously-formed patterns in the longitudinal magnetization.Comment: 5 pages, 4 figure

    GENERATION Z & CONSUMER TRENDS IN ENVIRONMENTAL PACKAGING

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    Efficient Light Management by Textured Nanoimprinted Layers for Perovskite Solar Cells

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    Inorganic organic perovskites like methylammonium lead iodide have proven to be an effective class of materials for fabricating efficient solar cells. To improve their performance, light management techniques using textured surfaces, similar to those used in established solar cell technologies, should be considered. Here, we apply a light management foil created by UV nanoimprint lithography on the glass side of an inverted p i n perovskite solar cell with 16.3 efficiency. The obtained 1 mA cm 2 increase in the short circuit current density translates to a relative improvement in cell performance of 5 , which results in a power conversion efficiency of 17.1 . Optical 3D simulations based on experimentally obtained parameters were used to support the experimental findings. A good match between the simulated and experimental data was obtained, validating the model. Optical simulations reveal that the main improvement in device performance is due to a reduction in total reflection and that relative improvement in the short circuit current density of up to 10 is possible for large area devices. Therefore, our results present the potential of light management foils for improving the device performance of perovskite solar cells and pave the way for further use of optical simulations in the field of perovskite solar cell

    39K and 77Se NMR study of the paraelectric-to-incommensurate phase transition of K2SeO4

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    Topic B, von Kienlin A, Gölzhäuser A, Haeberlin U, Blinc R. 39K and 77Se NMR study of the paraelectric-to-incommensurate phase transition of K2SeO4. Physical Review, B. 1988;38(13):8625-8632.The 39K quadrupole-coupling and chemical-shift tensors have been determined from the angular dependences of the 39K line shifts of the 39K±(1/2 ± 1) / 2 central NMR transitions in the paraelectric (P) and incommensurate (I) phases of K2SeO4. The main effect of the P-I phase transition on these tensors is the appearance of nonzero off-diagonal elements Vab and Vbc which reflects the destruction of mirror planes by frozen-in soft-mode displacements along the b axis. From the angular dependences of the 77Se line shifts the 77Se chemical-shift tensor has been determined in the paraelectric phase of K2SeO4. In contrast to the 39K quadrupole-coupling and chemical-shift tensors it remains unaffected on going through TI and changes only slightly at TC

    Management of infections pre- and post-liver transplantation: Report of an AISF consensus conference

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    The burden of infectious diseases both before and after liver transplantation is clearly attributable to the dysfunction of defensive mechanisms of the host, both as a result of cirrhosis, as well as the use of immunosuppressive agents. The present document represents the recommendations of an expert panel commended by the Italian Association for the Study of the Liver (AISF), on the prevention and management of infectious complications excluding hepatitis B, D, C, and HIV in the setting of liver transplantation. Due to a decreased response to vaccinations in cirrhosis as well as within the first six months after transplantation, the best timing for immunization is likely before transplant and early in the course of disease. Before transplantation, a vaccination panel including inactivated as well as live attenuated vaccines is recommended, while oral polio vaccine, Calmette-Guerin's bacillus, and Smallpox are contraindicated, whereas after transplantation, live attenuated vaccines are contraindicated. Before transplant, screening protocols should be divided into different levels according to the likelihood of infection, in order to reduce costs for the National Health Service. Recommended preoperative and postoperative prophylaxis varies according to the pathologic agent to which it is directed (bacterial vs. viral vs. fungal). Timing after transplantation greatly determines the most likely agent involved in post-transplant infections, and specific high-risk categories of patients have been identified that warrant closer surveillance. Clearly, specifically targeted treatment protocols are needed upon diagnosis of infections in both the pre- as well as the post-transplant scenarios, not without considering local microbiology and resistance patterns

    High Throughput Aging System for Parallel Maximum Power Point Tracking of Perovskite Solar Cells

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    In this research instrument article, the capabilities and details of a high throughput aging system for parallel maximum power point tracking MPPT of perovskite solar cells PSCs , capable of assessing the operational stability of a large number of devices, are presented. The intention is to provide insights into the machine and the development process to engineers who want to create a similar system and eventually make MPPT stability testing of PSCs a standard procedur

    Critical Exponents of the N-vector model

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    Recently the series for two RG functions (corresponding to the anomalous dimensions of the fields phi and phi^2) of the 3D phi^4 field theory have been extended to next order (seven loops) by Murray and Nickel. We examine here the influence of these additional terms on the estimates of critical exponents of the N-vector model, using some new ideas in the context of the Borel summation techniques. The estimates have slightly changed, but remain within errors of the previous evaluation. Exponents like eta (related to the field anomalous dimension), which were poorly determined in the previous evaluation of Le Guillou--Zinn-Justin, have seen their apparent errors significantly decrease. More importantly, perhaps, summation errors are better determined. The change in exponents affects the recently determined ratios of amplitudes and we report the corresponding new values. Finally, because an error has been discovered in the last order of the published epsilon=4-d expansions (order epsilon^5), we have also reanalyzed the determination of exponents from the epsilon-expansion. The conclusion is that the general agreement between epsilon-expansion and 3D series has improved with respect to Le Guillou--Zinn-Justin.Comment: TeX Files, 27 pages +2 figures; Some values are changed; references update

    Silicon solar cells on glass with power conversion efficiency above 13 at thickness below 15 micrometer

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    Liquid phase crystallized silicon on glass with a thickness of 10 40 amp; 956;m has the potential to reduce material costs and the environmental impact of crystalline silicon solar cells. Recently, wafer quality open circuit voltages of over 650 mV and remarkable photocurrent densities of over 30 mA cm 2 have been demonstrated on this material, however, a low fill factor was limiting the performance. In this work we present our latest cell progress on 13 amp; 956;m thin poly crystalline silicon fabricated by the liquid phase crystallization directly on glass. The contact system uses passivated back side silicon hetero junctions, back side KOH texture for light trapping and interdigitated ITO Ag contacts. The fill factors are up to 74 and efficiencies are 13.2 under AM1.5 g for two different doping densities of 1 10 17 cm 3 and 2 10 16 cm 3 . The former is limited by bulk and interface recombination, leading to a reduced saturation current density, the latter by series resistance causing a lower fill factor. Both are additionally limited by electrical shading and losses at grain boundaries and dislocations. A small 1 0.1 cm 2 test structure circumvents limitations of the contact design reaching an efficiency of 15.9 clearly showing the potential of the technolog

    Textured interfaces in monolithic perovskite silicon tandem solar cells advanced light management for improved efficiency and energy yield

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    Efficient light management in monolithic perovskite silicon tandem solar cells is one of the prerequisites for achieving high power conversion efficiencies PCEs . Textured silicon wafers can be utilized for light management, however, this is typically not compatible with perovskite solution processing. Here, we instead employ a textured light management LM foil on the front side of a tandem solar cell processed on a wafer with planar front side and textured back side. This way the PCE of monolithic, 2 terminal perovskite silicon heterojunction tandem solar cells is significantly improved from 23.4 to 25.5 . Furthermore, we validate an advanced numerical model for our fabricated device and use it to optically optimize a number of device designs with textures at different interface with respect to the PCE and energy yield. These simulations predict a slightly lower optimal bandgap of the perovskite top cell in a textured device as compared to a flat one and demonstrate strong interdependency between the bandgap and the texture position in the monolithic stack. We estimate the PCE potential for the best performing both side textured device to be 32.5 for a perovskite bandgap of 1.66 eV. Furthermore, the results show that under perpendicular illumination conditions, for optimized designs, the LM foil on top of the cell performs only slightly better than a flat anti reflective coating. However, under diffuse illumination, the benefits of the LM foil are much greater. Finally, we calculate the energy yield for the different device designs, based on true weather data for three different locations throughout the year, taking direct as well as diffuse illumination fully into account. The results further confirm the benefits of front side texture, even more for BIPV applications. Overall, devices built on a both side textured silicon wafer perform best. However, we show that devices with textured LM foils on the cell s front side are a highly efficient alternativ
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