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Optimisation of chemical purification conditions for direct application of solid metal salt coagulants:Treatment of peatland-derived diffuse runoff

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Journal of Environmental Sciences 2013年第4期25卷 659-669页

作者： Elisangela Heiderscheidt Jaakko Saukkoriipi Anna-Kaisa Ronkanen bjφrn Klφve Water Resources and Environmental Engineering Laboratory Department of Process and Environmental Engineering90014 University of OuluFinland Finnish Environment Institute(SYKE) Freshwater CentreMonitoring and AssessmentP.O.Box 413FI-90014University of OuluFinland

The drainage of peatland areas for peat extraction, agriculture or bioenergy requires affordable, simple and reliable treatment methods that can purify waters rich in particulates and dissolved organic carbon. This work focused on the optimisation of chemical purification process for the direct dosage of solid metal salt coagulants. It investigated process requirements of solid coagulants and the influence of water quality, temperature and process parameters on their performance. This is the first attempt to provide information on specific process requirements of solid coagulants. Three solid inorganic coagulants were evaluated： aluminium sulphate, ferric sulphate and ferric aluminium sulphate. Pre-dissolved aiuminium and ferric sulphate were also tested with the objective of identifying the effects of in-line coagulant dissolution on purification performance. It was determined that the pre-dissolution of the coagulants had a significant effect on coagulant performance and process requirements. Highest purification levels achieved by solid coagulants, even at 30% higher dosages, were generally lower （5%-30%） than those achieved by pre-dissolved coagulants. Furthermore, the mixing requirements of coagulants pre-dissolved prior to addition differed substantially from those of solid coagulants. The pH of the water samples being purified had a major influence on coagulant dosage and purification efficiency. Ferric sulphate （70 mg/L） was found to be the best performing solid coagulant achieving the following load removals： suspended solids （59%-88%）, total organic carbon （56%-62%）, total phosphorus （87%-90%）, phosphate phosphorus （85%-92%） and total nitrogen （33%-44%）. The results show that the use of solid coagulants is a viable option for the treatment of peatland-derived runoff water if solid coagulant-specific process requirements, such as mixing and settling time, are considered.

关键词： inorganic solid coagulant peatland runoff mixing chemical purification nutrients humic substances

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Stability of Finite Difference Discretizations of Multi-Physics Interface Conditions

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Communications in Computational Physics 2013年第2期13卷 386-410页

作者： björn Sjögreen Jeffrey W.Banks Center for Applied Scientific Computing Lawrence Livermore National LaboratoryLivermoreCA 94551USA

We considermulti-physics computationswhere theNavier-Stokes equations of compressible fluid flow on some parts of the computational domain are coupled to the equations of elasticity on other parts of the computational *** different subdomains are separated by well-defined *** consider time accurate computations resolving all time *** such computations,explicit time stepping is very *** address the issue of discrete interface conditions between the two domains of different physics that do not lead to instability,or to a significant reduction of the stable time step *** such interface conditions is *** discretize the problem with high order centered difference approximations with summation by parts boundary *** derive L2 stable interface conditions for the linearized one dimensional discretized ***,we generalize the interface conditions to the full non-linear equations and numerically demonstrate their stable and accurate performance on a simple model *** energy stable interface conditions derived here through symmetrization of the equations contain the interface conditions derived through normal mode analysis by Banks and Sj¨ogreen in[8]as a special case.

关键词： Fluid-structure interaction finite difference method summation by parts multiphysics interface condition

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Audio Enhancement for Computer Audition—An Iterative Training Paradigm Using Sample Importance

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Journal of Computer Science & Technology 2024年第4期39卷 895-911页

作者： Manuel Milling Shuo Liu Andreas Triantafyllopoulos Ilhan Aslan björn W.Schuller Chair of Embedded Intelligence for Health Care and Wellbeing University of AugsburgAugsburg 86159Germany Chair of Health Informatics München rechts der IsarTechnical University of MunichMunich 81675Germany Munich Center for Machine Learning Munich 80333Germany Huawei Technologies MunichMunich 80992Germany Munich Data Science Institute Garching 85748Germany Group on Language Audio and MusicImperial College LondonLondon SW72AZU.K.

Neural network models for audio tasks,such as automatic speech recognition(ASR)and acoustic scene classification(ASC),are susceptible to noise contamination for real-life *** improve audio quality,an enhancement module,which can be developed independently,is explicitly used at the front-end of the target audio *** this paper,we present an end-to-end learning solution to jointly optimise the models for audio enhancement(AE)and the subsequent *** guide the optimisation of the AE module towards a target application,and especially to overcome difficult samples,we make use of the sample-wise performance measure as an indication of sample *** experiments,we consider four representative applications to evaluate our training paradigm,i.e.,ASR,speech command recognition(SCR),speech emotion recognition(SER),and *** applications are associated with speech and nonspeech tasks concerning semantic and non-semantic features,transient and global information,and the experimental results indicate that our proposed approach can considerably boost the noise robustness of the models,especially at low signal-to-noise ratios,for a wide range of computer audition tasks in everyday-life noisy environments.

关键词： audio enhancement computer audition joint optimisation multi-task learning voice suppression

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Effects of different forms of nitrogen addition on microbial extracellular enzyme activity in temperate grassland soil

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Ecological Processes 2022年第1期11卷 483-490页

作者： Lili Dong björn Berg Weiping Gu Zhengwen Wang Tao Sun Erguna Forest-Steppe Ecotone Research Station Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Department of Forest Sciences University of Helsinki00014 HelsinkiFinland Section of Biology University of Gävle80176 GävleSweden Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China

Background:Nitrogen(N)deposition alters litter decomposition and soil carbon(C)sequestration by influencing the microbial community and its enzyme *** atmospheric N deposition comprises of inorganic N(IN)and organic N(ON)***,most studies have focused on IN and its effect on soil C cycling,whereas the effect of ON on microbial enzyme activity is poorly *** we studied the effects of different forms of externally supplied N on soil enzyme activities related to decomposition in a temperate *** nitrate was chosen as IN source,whereas urea and glycine were chosen as ON *** ratios of IN to ON(Control,10:0,7:3,5:5,3:7,and 0:10)were mixed with equal total amounts of N and then used to fertilize the grassland soils for 6 ***:Our results show that IN deposition inhibited lignin-degrading enzyme activity,such as phenol oxidase(POX)and peroxidase(PER),which may restrain decomposition and thus induce accumulation of recalcitrant organic C in grassland *** contrast,deposition of ON and mixed ON and IN enhanced most of the C-degrading enzyme activities,which may promote the organic matter decomposition in grassland *** addition,theβ-N-acetyl-glucosaminidase(NAG)activity was remarkably stimulated by fertilization with both IN and ON,maybe because of the elevated N availability and the lack of N limitation after long-term N fertilization at the grassland ***,differences in soil pH,soil dissolved organic carbon(DOC),and microbial biomass partially explained the differential effects on soil enzyme activity under different forms of N ***:Our results emphasize the importance of organic N deposition in controlling soil processes,which are regulated by microbial enzyme activities,and may consequently change the ecological effect of N ***,more ON deposition may promote the decomposition of soil organic matter thus converting C sequestration in grassland soils into a

关键词： Inorganic N deposition Organic N deposition Soil microbial biomass Microbial enzyme activity Decomposition Grassland

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Machine learning model for snow depth estimation using a multisensory ubiquitous platform

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Journal of Mountain Science 2022年第9期19卷 2506-2527页

作者： Sofeem NASIM Mourad OUSSALAH björn KLÖVE Ali Torabi HAGHIGHI Department of Computer Science and Engineering University of OuluOulu 90570Finland Water Energy and Environmental EngineeringUniversity of OuluOulu 90570Finland

Snow depth estimation is an important parameter that guides several hydrological applications and climate change *** advances in remote sensing technology and enhanced satellite observations,the estimation of snow depth at local scale still requires improved accuracy and *** advances in ubiquitous and wearable technology promote new prospects in tackling this *** this paper,a wearable IoT platform that exploits pressure and acoustic sensor readings to estimate and classify snow depth classes using some machine-learning models have been put ***,the results of Random Forest classifier showed an accuracy of 94%,indicating a promising alternative in snow depth measurement compared to in situ,LiDAR,or expensive large-scale wireless sensor network,which may foster the development of further affordable ecological monitoring systems based on cheap ubiquitous sensors.

关键词： Snow depth Wearable technology Machine learning Random forest classifier

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Self-flowing Cement-free MgO Castables Using a New Additive Package

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China's Refractories 2015年第1期24卷 38-43页

作者： Hong PENG bjrn MYHRE Elkem Silicon Materials

Although high-performance basic refractory materials play an essential role in state-of-the-art steel-making,magnesia castables have not been widely used until now. A major challenge is that brucite formation（ Mg（ OH）2） during Mg O hydration causes volume expansion and subsequent cracking—a phenomenon commonly called ＂slaking＂. To overcome problems related to slaking,a new specialty product,Siox X- Mag,has recently been developed for cement-free Mg O castables based on Mg O- SiO 2- H2 O bond. Specimens from industrial-scale-sized blocks after dry-out were characterised by SEM and XRD techniques. Using Siox X- Mag in combination with microsilica,cracking caused by brucite formation is suppressed. The results demonstrate that the dosage of microsilica plays essential roles in the crack formation in large samples. Furthermore,the compatibility of Siox X- Mag with different types of basic aggregates, medium to high-grade dead-burned magnesia and olivine, has also been evaluated. High-performance,self-flowing cement-free Mg O castables have been developed.

关键词： magnesia castable additive microsilica gel-bonded

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A Reinforcement Learning approach for the continuous electricity market ofGermany: Trading from the perspective of a wind park operator

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Energy and AI 2022年第2期8卷 67-78页

作者： Malte Lehna björn Hoppmann Christoph Scholz RenéHeinrich Fraunhofer Institute for Energy Economics and Energy System Technology(IEE) Königstor 5934119 KasselGermany

With the rising extension of renewable energies, the intraday electricity markets have recorded a growingpopularity amongst traders as well as electric utilities to cope with the induced volatility of the energysupply. Through their short trading horizon and continuous nature, the intraday markets offer the abilityto adjust trading decisions from the day-ahead market or reduce trading risk in a short-term notice. Producersof renewable energies utilize the intraday market to lower their forecast risk, by modifying their providedcapacities based on current forecasts. However, the market dynamics are complex due to the fact that thepower grids have to remain stable and electricity is only partly storable. Consequently, robust and intelligenttrading strategies are required that are capable to operate in the intraday market. In this work, we proposea novel autonomous trading approach based on Deep Reinforcement Learning (DRL) algorithms as a possiblesolution. For this purpose, we model the intraday trade as a Markov Decision Process (MDP) and employ theProximal Policy Optimization (PPO) algorithm as our DRL approach. A simulation framework is introducedthat enables the trading of the continuous intraday price in a resolution of one minute steps. We test ourframework in a case study from the perspective of a wind park operator. We include next to general tradeinformation both price and wind forecasts. On a test scenario of German intraday trading results from 2018,we are able to outperform multiple baselines with at least 45.24% improvement, showing the advantage of theDRL algorithm. However, we also discuss limitations and enhancements of the DRL agent, in order to increasethe performance in future works.

关键词： Deep Reinforcement Learning German intraday electricity trading Deep neural networks Markov Decision Process Proximal Policy Optimization Electricity price forecast

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Violent collisions can reveal hexadecapole deformation of nuclei

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Nuclear Science and Techniques 2024年第7期 70-72页

作者： bj?rn Schenke Physics Department Brookhaven National Laboratory

A new observable in heavy ion collision experiments was identified to be sensitive to the hexadecapole deformation of the colliding nuclei. Such deformation is difficult to measure in traditional nuclear electric transition measurements, as it is often overwhelmed by the nuclear quadrupole deformation. This opens the door to gain new insight into nuclear structure with experiments that were designed to study hot and dense nuclear *** structures are determined by the nuclear force, providing fundamental insight into the laws of nature. Deformations,quantifiedbydeviationsfromasphericalshape,area consequence of the interaction between the nuclear shell structure and the residual valence nucleons, whose detailed knowledge is crucial for understanding for example nucleosynthesis,nuclearfission,andneutrinolessdouble-beta decay.

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Comparison of Setting Behaviour and Mechanical Properties of Various Silica-bonded No-cement Castables

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China's Refractories 2017年第1期26卷 8-12页

作者： Hong PENG bjФrn MYHRE Elkem Silicon Materials Kristiansand NO-4621 Norway

Microsilica-gel bonded bauxite based no-cement refractory castables（NCCs）have been produced using two readily available *** NCCs were compared to NCC with Siox X-Zero,a purposely-developed product for microsilica-gel bonded no-cement castable systems to control flow properties and setting *** mixing and curing temperatures were applied：5℃,20℃and 35℃.The results show that setting-behaviour and mechanical properties strongly vary with the type of dispersant and the curing ***,both setting and strength are less temperature dependent in the castables with Siox ***,the drying and firing of microsilica-gel bonded NCCs were *** microsilica-gel bond system contains only a small amount of bound water,the castables can be fired at very high heating rates,once the free water has been removed.

关键词： dispersants setting curing temperature no-cement castable (NCCs) microsilica-gel bond fastdrying

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Toward implantable devices for angle-sensitive,lens-less,multifluorescent,single-photon lifetime imaging in the brain using Fabry-Perot and absorptive color filters

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Light(Science & Applications) 2022年第2期11卷 197-211页

作者： Adriaan J.Taal Changhyuk Lee Jaebin Choi björn Hellenkamp Kenneth L.Shepard Columbia University-Department of Electrical Engineering 500W.120th St.Mudd 1310New York 10027 NYUSA Korea Institute of Science and Technology-Brain Science Institute 5 Hwarang-ro 14-gilSeongbuk-guSeoul 02792Republic of Korea

Implantable image sensors have the potential to revolutionize *** to their small form factor requirements;however,conventional filters and optics cannot be *** limitations obstruct highresolution imaging of large neural *** advances in angle-sensitive image sensors and single-photon avalanche diodes have provided a path toward ultrathin lens-less fluorescence imaging,enabling plenoptic sensing by extending sensing capabilities to include photon arrival time and incident angle,thereby providing the opportunity for separability of fluorescence point sources within the context of light-field microscopy(LFM).However,the addition of spectral sensitivity to angle-sensitive LFM reduces imager resolution because each wavelength requires a separate pixel ***,we present a 1024-pixel,50μm thick implantable shank-based neural imager with color-filtergrating-based angle-sensitive *** angular-spectral sensitive front end combines a metal–insulator–metal(MIM)Fabry–Perot color filter and diffractive optics to produce the measurement of orthogonal light-field information from two distinct colors within a single *** result is the ability to add independent color sensing to LFM while doubling the effective pixel *** implantable imager combines angular-spectral and temporal information to demix and localize multispectral fluorescent *** this initial prototype,this is demonstrated with 45μm diameter fluorescently labeled beads in scattering *** lifetime imaging is exploited to further aid source separation,in addition to detecting pH through lifetime changes in fluorescent *** these initial fluorescent targets are considerably brighter than fluorescently labeled neurons,further improvements will allow the application of these techniques to in-vivo multifluorescent structural and functional neural imaging.

关键词： filters lifetime angle

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