C-Band Resistive SiC-MESFET mixer

In this paper the design and characterization of a linear C-band single ended resistive SiC-MESFET mixer is presented. The mixer has a minimum conversion loss of 7.8 dB and has a third order intermodulation intercept point of 30.3 dBm. The mixer is designed using a harmonic-balance simula-tion load-pull approach. This design method is especially use-ful for high-level mixers, where small-signal approximations cannot be used

Validating the Harmonic Balance Method for Turbomachinery Tonal Noise Predictions

A computational method for predicting turbomachinery tonal noise is presented. It is based on the Harmonic Balance method, which solves for the dominant frequencies of the flow generated by bladerow interaction. Coupling between the resolved frequencies is furthermore enabled since the Harmonic Balance method is applicable to the nonlinear Euler or Navier-Stokes equations. The implementation is also validated against two cases from the Fourth Computational Aeroacoustics Workshop on Benchmark Problems hosted by NASA. The computational setup is explained in detail and specific challenges encountered in both benchmark problems are discussed. Results generally show very good agreement with data published by several other authors, giving confidence in the capability of the method. Some remaining challenges for the implemented method necessary to compute full scale turbomachinery noise are also identified and discussed

Betyg och bedömning i musik och slöjd.

Syfte och huvudfråga Syftet med uppsatsen är att belysa hur lärare i praktiska ämnen som musik och slöjd ställer sig till det målrelaterade betygsystemet när det gäller bedömning av elevers prestationsutveckling. Därtill undersöks hur dessa lärare ställer sig till förändringen av betygsystemet som eventuellt kommer att träda i kraft, och hur det i så fall skulle påverka deras undervisning och betygsättning. Metod och material Undersökningen genomfördes med hjälp av kvalitativa forskningsintervjuer där lärare från grundskolans senare år fick ge sin bild av det svenska betygsystemet, och dess eventuella förändringar. Dessa data kompletterades sedan med skriftliga källor och egna observationer. Resultat Undersökningen visar att det finns såväl skillnader som likheter mellan hur lärare i slöjd respektive musik undervisar, bedömer och betygsätter sina elever. En genomgående tendens är dock att alla tillfrågade lärare efterfrågar mer tid till dokumentation och diskussion lärare emellan om hur de nationella målen och kriterierna skall tolkas. När det gäller betygsättning och bedömning i praktiska ämnen ter sig denna uppgift ännu svårare då dessa enligt verksamma lärare är abstrakta ämnen, där tolkningar och kunskapssyn ser mycket olika ut från skola till skola. En större diskussion inom respektive ämne, både lokalt och nationellt, vore därför nödvändigt för att ge eleverna en så grundläggande och rättvis undervisning som möjligt. Betydelse för läraryrket Med utgångspunkt i vårt intervjumaterial efterfrågar vi ny forskning kring införandet av en ny betygsskala. Betygsberedningen bör vara väl förbered inför det stundande betygsskiftet, där mål och kriterier är noggrant och tydligt uppställda, och där tid måste avsättas för att lärare och andra personer som är verksamma inom skolväsendet får tid och möjlighet att sätta sig in i det nya systemet. Något som också är nödvändigt är att lärarkåren själva bidrar till den kringliggande debatt som pågår i samhället kring betyg och bedömning

Better Regulation in Europe

Better Regulation is afoot in Europe. After several transatlantic conflicts over regulatory topics such as the precautionary principle, genetically modified foods, and climate change, Europe and America now appear to be converging on the analytic basis for regulation. In a process of hybridization, European institutions are borrowing Better Regulation reforms from both the US approach to regulatory review using benefit-cost analysis and from European member states\u27 initiatives on administrative costs and simplification; in turn the European Commission is helping to spread these reforms among the member states. In many respects, the Better Regulation initiative promises salutary reforms, such as wider use of regulatory impact assessments and a reduction in unnecessary bureaucracy. In other respects, the European initiative speaks more of Procrustean deregulation than of better regulation. Meanwhile the European Commission still needs to establish the institutional infrastructure needed to succeed. This paper argues that the European program of Better Regulation is well-founded but could be even better if it adopted several strategies: enlarging the scope of impact assessment and benefit-cost analysis toward a broader, warmer and more evenhanded application of these tools, with greater attention to multiple risks; moving beyond a narrow focus on cutting administrative costs or simplification for their own sake, toward criteria that address benefits as well as costs; centralizing expert oversight so that impact assessments actually influence decisions, both to say no to bad ideas and yes to good ideas; and undertaking ex post evaluation of policies for adaptive policy revision and for improvement of ex ante assessment methods. These reforms would help Better Regulation achieve its true objective: better, not less or more. In turn, the US could study these European innovations and borrow from them where they prove successful

Keeping Secrets: The Unsettled Law of Judge-Made Exceptions to Grand Jury Secrecy

Federal Rule of Criminal Procedure 6(e) functionally binds everyone who is present during grand jury proceedings (except witnesses) to secrecy. But questions arise when courts are asked to make exceptions to grand jury secrecy outside those enumerated in the rule, such as exceptions for Congress or for the release of historically significant grand jury records. This Note examines the propriety of judge-made exceptions to grand jury secrecy. Contrary to some courts authorizing disclosure outside of Rule 6(e), this Note argues that the text and development of Rule 6(e), along with limitations on courts’ inherent authority over grand jury procedure, caution against this practice. The tension between the current practice of some courts and the apparent meaning of Rule 6(e) renders the law of grand jury secrecy unsettled. To clarify the law, the Advisory Committee on Criminal Rules should add a residual exception to Rule 6(e) that would not only give courts flexibility and discretion but also a clear source of authority on which to authorize disclosures

Living Labs as Tools for Open Innovation

This paper presents a Living Lab in Stockholm as a focal point for discussing how the Living Lab concept can be extended and used for engaging in multiorganizational open innovation. Although Living Labs have been found to have potential for driving innovation through collaboration, more research is necessary to find tangible ways of organizing this kind of collaboration. The paper is explorative and empirically induced from an ongoing development and practical implementation of a Living Lab at Stockholm-Arlanda Airport - Sweden's largest airport situated outside Stockholm. This Airport Living Lab involves a number of large industrial and academic stakeholders aiming at ensuring multi-organizational innovation delivery. Of special interest is how the Living Lab concept should evolve to continue creating conditions for user-oriented innovations through multi-organizational collaboration which would not necessarily take place otherwise. Congruent with the explorative aim of the paper it ends up in a discussion about five propositions that should be on the agenda of research and implementation for Living Lab founders in the coming years.Living Labs, Open innovation, Electronic Collaboration Tools

Supersonic Jet Excitation using Flapping Injection

Supersonic jet noise reduction is important for high speed military aircraft. Lower acoustic levels would reduce structural fatigue leading to longer lifetime of the jet aircraft. It is not solely structural aspects which are of importance, health issues of the pilot and the airfield per- sonnel are also very important, as high acoustic levels may result in severe hearing damage. It remains a major challenge to reduce the overall noise levels of the aircraft, where the supersonic exhaust is the main noise source for near ground operation. Fluidic injection into the supersonic jet at the nozzle exhaust has been shown as a promising method for noise reduction. It has been shown to speed up the mix- ing process of the main jet, hence reducing the kinetic energy level of the jet and the power of the total acoustic radiation. Furthermore, the interaction mechanism between the fluidic injection and the shock structure in the jet exhaust plays a crucial role in the total noise radia- tion. In this study, LES is used to investigate the change in flow struc- tures of a supersonic (M=1.56) jet from a converging-diverging nozzle. Six fluidic actuators, evenly distributed around the nozzle exit, inject air in a radial direction towards the main flow axis with a total mass flow ratio of 3%. Steady injection is compared with flapping injection. With flapping injection turned on, the injection angle of each injector is varied sinusoidally in the nozzle exit plane and the variation is the same for all injectors. This fluid dynamics video is submitted to the APS DFD Gallery of Fluid Motion 2013 at the 66 the Annual Meeting of the American Physical Society, Division of Fluid Dynamics (24-26 November, Pittsburgh, PA, USA).Comment: 3 pages, 2 linked animations/video

Cat and house dust mite allergen content is stable in frozen dust over time

Background: Dust from indoor environments consists of animal allergens, pollen, endotoxins and other substances which may exacerbate symptoms in sensitive individuals. In prospective cohort studies, dust is often collected from indoor environments in order to assess allergen exposure and possible relationships to health outcomes. Typically, large numbers of samples are collected and kept frozen until further analysis, sometimes several years later. To date, there is insufficient knowledge about what happens to the dust and its contents during storage. Objectives: In the present study, our aim was to analyse allergen content over a 30 month period frozen dust collected from beds in homes in order to simulate a study design of exposure assessment commonly used in epidemiological studies. Methods: Thirty-seven dust samples from mattresses in homes were collected using a Duststream dust collector. Each dust sample was subdivided into six aliquots. One tube (baseline) was extracted and analysed for cat and HDM allergen content using ELISA, all other tubes were stored at -80°C until further handling. Approximately every six months (6, 12, 18 and 30 months), dust from one tube was thawed, extracted and analysed the same way. Data was log-transformed and analysed using linear regression. Results: No trend for decreasing or increasing cat (p=0.606) or house dust mite (p=0.928)allergen levels could be observed over time. Levels of cat allergen were considerably higher in mattresses from homes with cats compared to homes without cats (p<0.001). Conclusion: It is important to assess the allergen stability in dust before designing costly and labour-intensive studies of allergen exposure and health outcomes, commonly used in environmental epidemiology. Although the present study showed that cat and HDM allergens 3 remained stable in dust stored at -80°C during a 2.5 year period, analyses of other allergens or substances in frozen dust is desirable as well as evaluating the effect of longer storage times.VetenskapsrådetAFAManuscrip

Optimization study on periodic counter-current chromatography (PCC) integrated in a mAb downstream process

In the biopharmaceutical market, there is an increasing pressure to reduce prices. Nowadays, a big part of the manufacturing cost is due to the product purification. A big effort has been made in this matter to reduce costs, and continuous downstream processes like periodic counter-current chromatography (PCC) have gained interest in the last years due to a higher productivity and resin utilization compared to a batch process. Herein, a PCC process is integrated with a virus inactivation and two ion-exchange chromatography steps (polishing steps) for the purification of mAb at lab scale, and multi-objective optimization is used to compare several process configurations using two resins with different particle sizes. Please click Additional Files below to see the full abstract