| 1. |
- Liu, Sirui, et al.
(författare)
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Design of Hygroscopic Bioplastic Products Stable in Varying Humidities
- 2023
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Ingår i: Macromolecular materials and engineering. - : Wiley. - 1438-7492 .- 1439-2054. ; 308:2
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Tidskriftsartikel (refereegranskat)abstract
- Hygroscopic biopolymers like proteins and polysaccharides suffer from humidity-dependent mechanical properties. Because humidity can vary significantly over the year, or even within a day, these polymers will not generally have stable properties during their lifetimes. On wheat gluten, a model highly hygroscopic biopolymer material, it is observed that larger/thicker samples can be significantly more mechanically stable than thinner samples. It is shown here that this is due to slow water diffusion, which, in turn, is due to the rigid polymer structure caused by the double-bond character of the peptide bond, the many bulky peptide side groups, and the hydrogen bond network. More than a year is required to reach complete moisture saturation (≈10 wt.%) in a 1 cm thick plate of glycerol-plasticized wheat gluten, whereas this process takes only one day for a 0.5 mm thick plate. The overall moisture uptake is also retarded by swelling-induced mechanical effects. Hence, hygroscopic biopolymers are better suited for larger/thicker products, where the moisture-induced changes in mechanical properties are smeared out over time, to the extent that the product remains sufficiently tough over climate changes, for example, throughout the course of a year.
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| 2. |
- Zhang, Di, et al.
(författare)
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Recent Developments in Palladium-Catalyzed Oxidative Cascade Carbocyclization
- 2017
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Ingår i: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 7:10, s. 7051-7063
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Tidskriftsartikel (refereegranskat)abstract
- In this Perspective, we describe recent advances on Pd-catalyzed oxidative cascade carbocyclizations. These cascade processes enable efficient construction of the molecular complexity and structural diversity of carbocyclic compounds via introducing diverse functionalities concomitant with multiple C-C bond-formations in one-pot operations. In many cases, these processes are facilitated by Pd-catalysts alone, while cocatalysis by combination of Pd catalyst and other catalysts are also discussed, since they represent a new entry to address the preparation of functionalized cyclic compounds with high efficiency and selectivity.
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| 3. |
- Zhu, Youjian, et al.
(författare)
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Effect of sodium carboxymethyl cellulose addition on particulate matter emissions during biomass pellet combustion
- 2018
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 230, s. 925-934
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Tidskriftsartikel (refereegranskat)abstract
- Sodium carboxymethyl cellulose (CMC) can be used as a cost-effective and environmentally friendly binder in the pelletizing process for production of biomass pellets with good quality. However, the effect of its addition on the emission of particulate matters (PM) during the combustion process, are still not clear. In this study, four typical biomass fuels, cotton stalk, cornstalk, camphorwood and rice husk, were used to investigate the effect of the addition of 5 wt% CMC in the biomass pellets on PM emissions during the combustion process. In the case of pure CMC combustion, a large amount of PM mainly with PM2.5 were generated, which was associated to the evaporation and condensation of NaOH and Na2CO3. The PM10 emission from the combustion of the four biomass fuels varied from 9.72 mg/Nm3 to 23.12 mg/Nm3 with mainly PM1. The addition of 5 wt% CMC in cotton stalk, corn stalk and camphorwood significantly increased the PM emissions due to the evaporation and subsequent condensation of Na-containing species, e.g. NaCl, Na2SO4, NaOH and Na2CO3. For rice husk, the addition of CMC hardly affected PM1 emission due to the dominated SiO2 component in rice husk ash, which reacted with the Na-containing species from the combustion of CMC and facilitated the formation of coarse ash particles and the reduction of PM1 emission. Although the addition of CMC in biomass fuels can greatly enhance the pellets qualities, its addition increases the PM emissions to varying degree. Therefore, in the industrial application of CMC to biomass densification, countermeasures such as mixing of high Si-containing rice husk or SiO2-rich minerals with biomass fuels should be taken to alleviate the PM issues resulting from the introduction of CMC.
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| 4. |
- Alonso-Blanco, Carlos, et al.
(författare)
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1,135 Genomes Reveal the Global Pattern of Polymorphism in Arabidopsis thaliana
- 2016
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Ingår i: Cell. - : Elsevier. - 0092-8674 .- 1097-4172. ; 166:2, s. 481-491
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Tidskriftsartikel (refereegranskat)abstract
- Arabidopsis thaliana serves as a model organism for the study of fundamental physiological, cellular, and molecular processes. It has also greatly advanced our understanding of intraspecific genome variation. We present a detailed map of variation in 1,135 high-quality re-sequenced natural inbred lines representing the native Eurasian and North African range and recently colonized North America. We identify relict populations that continue to inhabit ancestral habitats, primarily in the Iberian Peninsula. They have mixed with a lineage that has spread to northern latitudes from an unknown glacial refugium and is now found in a much broader spectrum of habitats. Insights into the history of the species and the fine-scale distribution of genetic diversity provide the basis for full exploitation of A. thaliana natural variation through integration of genomes and epigenomes with molecular and non-molecular phenotypes.
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| 5. |
- Chen, Xu, et al.
(författare)
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Catalytic fast pyrolysis of biomass to produce furfural using heterogeneous catalysts
- 2017
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 0165-2370 .- 1873-250X. ; 127, s. 292-298
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Tidskriftsartikel (refereegranskat)abstract
- Furfural is a valuable chemical, the production of furfural from renewable biomass resources becomes more attractive in recent years. In this study, biomass fast pyrolysis with heterogeneous catalysts (titanium compounds (TiN, TiO2 and TiOSO4) and metal nitrides (MoN, GaN and VN)) for furfural production was investigated experimentally by means of pyrolysis-gas chromatography/mass-spectrometry (Py-GC/MS). The measurement results indicated that TiN and GaN promoted the furfural compounds production notably mainly through direct decomposition of oligosaccharides. The formation of furfural was promoted when the amount of TiN was increased, and the yield of furfural formed was about 5.5 times the size of that from non-catalytic pyrolysis when TiN/cellulose mass ratio was 4. The furfural yield decreased when the pyrolysis residence time increased from 10 to 30 s, which suggests competitive reactions (formation of 1, 6-anhydro-beta.-D-glucopyranose) against the formation of furfural. TiN, as a catalyst for fast pyrolysis towards furfural production, can be well applied to agriculture biomass residues. Comparing three biomass residues: corncob, wheat straw and cotton stalk, corncob showed higher furfural yield due to the higher holocellulose content, while wheat straw showed higher furfural selectivity.
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| 6. |
- Gidlund, Mikael, et al.
(författare)
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Wireless communication method and system with collision avoidance protocol
- 2015
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Patent (populärvet., debatt m.m.)abstract
- The invention concerns a method for providing wireless communication between a source node and a destination node in a wireless network wherein said wireless network uses a time division multiple access (TDMA) protocol. One or more dedicated TDMA transaction timeslots (60-71) are arranged in a superframe. The superframe comprises at least one dedicated transaction slot forming a hybrid protocol with two or more shared transaction slots 50 per superframe. The method is of particular advantage when practised with a WirelessHART protocol wireless sensor network and when used for monitoring and control equipment and processes in an industrial installation. A computer program, and a wireless node and a wireless network using the inventive method are also disclosed.
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| 7. |
- Gulliksson, Mårten, et al.
(författare)
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Perturbation bounds for constrained and weighted least squares problems
- 2002
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Ingår i: Linear Algebra and Its Applications. - 0024-3795. ; 349, s. 221-232
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Tidskriftsartikel (refereegranskat)abstract
- We derive perturbation bounds for the constrained and weighted linear least squares (LS) problems. Both the full rank and rank-deficient cases are considered. The analysis generalizes some results of earlier works.
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| 8. |
- Gulliksson, Mårten, et al.
(författare)
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Perturbation identities for regularized Tikhonov inverses and weighted pseudoinverses
- 2000
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Ingår i: Bit: numerical mathematics. - 0006-3835. ; 40:3, s. 513-523
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Tidskriftsartikel (refereegranskat)abstract
- e consider the perturbation analysis of two important problems for solving ill-conditioned or rank-deficient linear least squares problems. The Tikhonov regularized problem is a linear least squares problem with a regularization term balancing the size of the residual against the size of the weighted solution. The weight matrix can be a non-square matrix (usually with fewer rows than columns). The minimum-norm problem is the minimization of the size of the weighted solutions given by the set of solutions to the, possibly rank-deficient, linear least squares problem. It is well known that the solution of the Tikhonov problem tends to the minimum-norm solution as the regularization parameter of the Tikhonov problem tends to zero. Using this fact and the generalized singular value decomposition enable us to make a perturbation analysis of the minimum-norm problem with perturbation results for the Tikhonov problem. From the analysis we attain perturbation identities for Tikhonov inverses and weighted pseudoinverses.
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| 9. |
- Hongwei, Huo, et al.
(författare)
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A Virtual Hypercube Routing Algorithm for Wireless Healthcare Networks
- 2010
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Ingår i: Chinese journal of electronics. - 1022-4653 .- 2075-5597. ; 19:1E, s. 138-144
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Tidskriftsartikel (refereegranskat)abstract
- Abstract|The application scenarios of wireless sensornetworks for health care systems are very complex, whichrequire a new communication schemes that can dynami-cally ful¯ll these requirements and achieve e±cient datatransmission. It brings a big challenge to routing, accesscontrol, data transmission, storage and processing. Thispaper presents a novel routing scheme named Virtual hy-percube routing (VHR), in which the routing selection andmaintenance rules are de¯ned based on a logical hypercubestructure. It can highlight good performance in data trans-fer rate and query e±ciency. Based on this structure, therouting for health care can be implemented e±ciently. Weevaluate the performance of VHR using simulation underhome and public area care scenarios. The results show thatthis scheme performs high data transfer rate, low latencyand low overhead for communication under both static anddynamic scenarios.
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| 10. |
- Huang, Ivy, et al.
(författare)
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High performance dual-electrolyte magnesium-iodine batteries that can harmlessly resorb in the environment or in the body
- 2022
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 15:10, s. 4095-4108
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Tidskriftsartikel (refereegranskat)abstract
- Batteries represent the dominant means for storing electrical energy, but many battery chemistries create waste streams that are difficult to manage, and most possess toxic components that limit their use in biomedical applications. Batteries constructed from materials capable of complete, harmless resorption into the environment or into living organisms after a desired period of operation bypass these disadvantages. However, previously reported eco/bioresorbable batteries offer low operating voltages and modest energy densities. Here, we introduce a magnesium-iodine chemistry and dual (ionic liquid/aqueous) electrolyte to overcome these limitations, enabling significant improvements in voltage, areal capacity, areal energy, areal power, volumetric energy, and volumetric power densities over any alternative. Systematic studies reveal key materials and design considerations. Demonstrations of this technology include power supplies for cardiac pacemakers, wireless environmental monitors, and thermal sensors/actuators. These results suggest strong potential for applications where commercial battery alternatives pose risks to the environment or the human body.
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