On the leading edge noise and aerodynamics of thin aerofoil subjected to the straight and curved serrations

This paper presents the results of an experimental study into the effect of add-on type leading edge serrations on the aeroacoustic and aerodynamic performances of a symmetrical NACA0008 aerofoil. The aeroacoustic part of this paper studies the reduction of interaction broadband noise in the presence of elevated freestream turbulence by employing serrated leading edges. For non-dimensional frequencies f0 < 1, the resulting sound pressure level reduction (DSPL) was found to be a linear function of f0 and the DSPL depends only on the serration amplitude, serration wavelength and freestream velocity. Leading edge with a large serration amplitude was found to be very effective in the reduction of broadband noise where up to DSPL z 8 dB is achievable. It is generally more beneficial to choose a leading edge with a smaller serration wavelength, although the most effective configuration actually combines the largest serration amplitude and the largest serration wavelength. Interestingly, for a curved-serration, the most optimised configuration (with small serration wavelength, large serration amplitude, small inclination angle and large curvature radius) was found to outperform its straight-serration counterpart by a further 5 dB reduction of broadband noise at the same frequency. Concerning the aerodynamic part of the study, to effectively suppress boundary layer stall without incurring severe drag penalties for low freestream turbulence intensity, the most effective leading edge serration should possess a large serration wavelength and small serration amplitude. Hence, the serration geometry that works very well for a low noise aerofoil is usually inferior in the aerodynamic performance, and vice versa. The best compromise for the serration geometry that can still harness good performances in both the aeroacoustic and aerodynamic should possess the largest serration amplitude and the largest serration wavelength. This paper demonstrates that, when optimised properly, the add-on type leading edge serration can be very effective in both the reduction of the interaction broadband noise, and the suppression of the boundary layer separation at high angle of attack.Engineering and Physical Sciences Research Counci

Leading edge noise reduction of thin aerofoil by the straight and curved serrations of the add-on type

This paper presents the experimental results of the effect of add-on type leading edge serrations on the aeroacoustic performance of a symmetrical NACA0008 aerofoil. The focus is on the turbulence-leading edge interaction broadband noise. Tests have been conducted in an aeroacoustic open jet wind tunnel at Brunel University London. 25 serrated leading edges (straight) that can be adequately described by their serration wavelength and serration amplitude h have been investigated at Reynolds numbers between 0.2 and 0.6 millions. It was found that those with large h are very effective in reducing the broadband noise levels up to about 9 dB. However, the serration designs with smaller h can produce noticeable levels of noise increase at high frequency. The effect of the on the noise reduction depends on the corresponding h value. For example, a particular design with both the largest and h has been shown to be very effective. Another one with a similar , but the smallest h can actually degrade the performance significantly where noise increase over the baseline aerofoil becomes dominant. The curved-serration has been shown to be able to outperform the straight-serration counterpart by a further 5 dB broadband noise reduction when it is optimised properly. The mechanism is due to the increase of the “effective” serration amplitude h as a result of the curvature although its “normal” serration amplitude h actually remains the same as the straight-serration counterpart. Currently, there is no evidence to support the hypothesis that the peak of the curved-serration can prevent the interaction between the grid-generated turbulence structures and the serration troughs. Overall, the add-on type leading edge serration has been shown to be very effective in the reduction of the interaction broadband noise. The nature-inspired concept of a curvedserration at the leading edge provides an avenue for further research

Oxidative damages in tubular epithelial cells in IgA nephropathy: role of crosstalk between angiotensin II and aldosterone

<p>Abstract</p> <p>Background</p> <p>Inhibition of the renin-angiotensin-aldosterone system (RAAS) slows down the progression of chronic renal diseases (CKD) including IgA nephropathy (IgAN). Herein, we studied the pathogenetic roles of aldosterone (Aldo) in IgAN.</p> <p>Methods</p> <p>Human mesangial cells (HMC) was activated with polymeric IgA (pIgA) from IgAN patients and the effects on the expression of RAAS components and TGF-β synthesis examined. To study the roles of RAAS in the glomerulotubular communication, proximal tubular epithelial cells (PTEC) was cultured with conditioned medium from pIgA-activated HMC with eplerenone or PD123319, the associated apoptotic event was measured by the generation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and reactive oxygen species (ROS).</p> <p>Results</p> <p>Polymeric IgA up-regulated the Aldo synthesis and aldosterone synthase expression by HMC. The release of TGF-β by HMC was up-regulated synergistically by AngII and Aldo and this was inhibited by incubation of HMC with losartan plus eplerenone. Cultured PTEC express the mineralocorticoid receptor, but not synthesizing aldosterone. Apoptosis, demonstrated by cleaved PARP expression and caspase 3 activity, was induced in PTEC activated by conditioned medium prepared from HMC cultured with pIgA from IgAN patients. This apoptotic event was associated with increased generation of NADPH oxidase and ROS. Pre-incubation of PTEC with PD123319 and eplerenone achieved complete inhibition of PTEC apoptosis.</p> <p>Conclusions</p> <p>Our data suggest that AngII and Aldo, released by pIgA activated HMC, served as mediators for inducing apoptosis of PTEC in glomerulo-tubular communications. Crosstalk between AngII and Aldo could participate in determining the tubular pathology of IgAN.</p

EVS - European Values Study 1999 - Lithuania

Moral, religious, societal, political, work, and family values of Europeans. Topics: Leisure time: importance of areas of life; feeling of happiness; memberships and honorary activities in clubs, parties, organizations, citizens´ initiatives and occupation organizations; interactions in leisure time; tolerance regarding minorities, those of other beliefs and foreigners; inter-human trust; self-effectiveness (scale); general contentment with life (scale). Work: importance of selected characteristics of occupational work (scale); personal employment; general work satisfaction (scale); self-determination at work (scale); work ethic (scale); attitude to achievement-based pay and following work instructions without criticism; priority of nationals over foreigners as well as men over women with shortage of jobs; assumed priority of individual or social reasons for the situation of economic need of individuals; freedom of the unemployed to reject a job offer (scale). Politics: party preference; attitude to foreign workers in one´s country; fear of the future; assimilation and integration of immigrants; concept of a just society (more welfare state or liberalism, scale); interest in political news in the media; individualism and thinking of the community; interest in politics; political participation; self-assessment on a left-right continuum (scale); self-responsibility or governmental provision (scale); attitude to competition freedom and entrepreneur freedom (scale); satisfaction with democracy; attitude to the current political system of the country and judgment on the political system of the country ten years ago (scale); preference for a democratic political system or for strong leadership of an individual politician (scale); attitude to democracy (scale); loss of national characteristics through unification of Europe. Religion: individual or general standard for good and evil; current and perhaps earlier religious denomination; current frequency of church attendance and at the age of 12; importance of religious celebration at birth, marriage and funeral; self-assessment of religiousness; ability of the religious community in moral questions, with problems in family life, spiritual needs and current social problems of the country; belief in God, life after death, hell, heaven, sin, telepathy and reincarnation; belief in God or nihilism (scale); importance of God in one´s own life (scale); comfort and strength through belief; prayer and meditation; frequency of prayer; possession and belief in lucky charms or talisman (scale); reading and observing horoscopes; attitude to separation of church (religion) and state (scale). Family and marriage: important criteria for a successful marriage (scale); attitude to marriage and the traditional family structure (scale); attitude to one´s own children (scale); attitude to traditional understanding of one´s role of man and woman in occupation and family (scale); attitude to a traditional or liberal parent-child relation; importance of educational goals; attitude to abortion. Society: preference for individual freedom or social equality; post-materialism (scale); preferred social development (scale); attitude to technical progress; trust in institutions; observing individual human rights in the country; attitude to environmental protection (scale); closeness to family, the neighborhood, people in the region, countrymen, Europeans and humanity; closeness to older people, the unemployed, foreigners and handicapped well as readiness to make an effort for these groups; personal reasons for assistance with older people as well as foreigners; identification with the city, the region, the nation, Europe and the world; national pride. morals and sexuality: moral attitudes (tax evasion, theft, use of drugs, lying, bribe money, corruption, euthanasia, suicide, environmental pollution, alcohol at the wheel; scale); moral attitudes to partnership and sexuality (homosexuality, abortion, divorce, promiscuity; scale); assumed spreading of immoral behavior in the population of the country (scale); attitude to punishment dependent on the situation of the culprit or the victim (scale). Demography: sex; year of birth; marital status and living together with a partner; number of children; school education; age at termination of school training; employment; superior function and span of control; company size; occupation (ISCO88) and occupational position; length of unemployment; size of household; ages of children in household; head of household; characteristics of head of household; household income. Additional country specific questions included. Interviewer rating: willingness of respondent to cooperate. Also coded: city size; region; date of interview; length of interview.Moralische, religiöse, gesellschaftliche, politische, ökonomische und soziale Wertvorstellungen der Europäer. Themen: Freizeit: Wichtigkeit der Lebensbereiche; Glücksgefühl; Mitgliedschaften und ehrenamtliche Tätigkeiten in Vereinen, Parteien, Organisationen, Bürgerinitiativen und Berufsorganisationen; Verkehrskreise in der Freizeit; Toleranz gegenüber Minderheiten, Andersgläubige und Ausländer; zwischenmenschliches Vertrauen; Selbstwirksamkeit (Skalometer); allgemeine Lebenszufriedenheit (Skalometer). Arbeitswelt: Wichtigkeit ausgewählter Merkmale beruflicher Arbeit (Skala); eigene Erwerbstätigkeit; allgemeine Arbeitszufriedenheit (Skalometer); Selbstbestimmung in der Arbeit (Skalometer); Arbeitsethos (Skala); Einstellung zu einer leistungsorientierten Bezahlung und zum kritiklosen Befolgen von Arbeitsanweisungen; Priorität von Inländern gegenüber Ausländern sowie Männern gegenüber Frauen bei Arbeitsplatzknappheit; vermuteter Vorrang individueller oder gesellschaftlicher Ursachen für die wirtschaftliche Notlage Einzelner; Entscheidungsfreiheit von Arbeitslosen zur Ablehnung eines Arbeitsangebots (Skalometer). Politik: Parteipräferenz; Einstellung zu ausländischen Arbeitnehmern im eigenen Land; Zukunftsangst; Assimilation und Integration von Immigranten; Vorstellung von einer gerechten Gesellschaft (mehr Wohlfahrtsstaat oder Liberalismus, Skala); Interesse an politischen Nachrichten in den Medien; Individualismus und Gemeinschaftsdenken; Politikinteresse; politische Partizipation; Selbsteinschätzung auf einem Links-Rechts-Kontinuum (Skalometer); Selbstverantwortlichkeit oder staatliche Vorsorge (Skalometer); Einstellung zur Wettbewerbsfreiheit und Unternehmerfreiheit (Skalometer); Demokratiezufriedenheit; Einstellung zum derzeitigen politischen System des Landes und Beurteilung des politischen Systems des Landes vor zehn Jahren (Skalometer); Präferenz für ein demokratisches politisches System oder für eine starke Führerschaft eines einzelnen Politikers (Skala); Einstellung zur Demokratie (Skala); Verlust nationaler Charakteristika durch die Vereinigung Europas. Religion: individueller oder genereller Maßstab für Gut und Böse; derzeitige und gegebenenfalls frühere Konfession; derzeitige Kirchgangshäufigkeit und im Alter von 12 Jahren; Wichtigkeit religiöser Feiern bei Geburt, Hochzeit und Beerdigung; Selbsteinschätzung der Religiosität; Kompetenz der Religionsgemeinschaft in moralischen Fragen, bei Problemen im Familienleben, bei geistigen Bedürfnissen und aktuellen sozialen Problemen des Landes; Glaube an Gott, an ein Leben nach dem Tod, an die Hölle, den Himmel, die Sünde, an Telepathie und an Wiedergeburt; Gottgläubigkeit oder Nihilismus (Skala); Wichtigkeit von Gott im eigenen Leben (Skalometer); Trost und Kraft durch den Glauben; Beten und Meditation; Gebetshäufigkeit; Besitz und Glauben an Glücksbringer oder Talisman (Skalometer); Lesen und Berücksichtigen von Horoskopen; Einstellung zur Trennung von Kirche (Religion) und Staat (Skala). Familie und Ehe: wichtigste Kriterien für eine erfolgreiche Ehe (Skala); Einstellung zur Ehe und zur traditionellen Familienstruktur (Skala); Einstellung zu eigenen Kindern (Skala); Einstellung zum traditionellen Rollenverständnis von Mann und Frau in Beruf und Familie (Skala); Einstellung zu einer traditionellen oder liberalen Eltern-Kind-Beziehung; Wichtigkeit von Erziehungszielen; Einstellung zur Abtreibung. Gesellschaft: Präferenz für individuelle Freiheit oder soziale Gleichheit; Postmaterialismus (Skala); präferierte gesellschaftliche Entwicklung (Skala); Einstellung zum technischen Fortschritt; Vertrauen in Institutionen; Beachtung der individuellen Menschenrechte im Lande; Einstellung zum Umweltschutz (Skala); Nähe zur Familie, zur Nachbarschaft, den Menschen in der Region, zu den Landsleuten, den Europäern und der Menschheit; Nähe zu älteren Menschen, zu Arbeitslosen, Ausländern und Behinderten sowie Bereitschaft sich für diese Gruppen einzusetzen; persönliche Gründe für Hilfeleistungen bei älteren Menschen sowie bei Ausländern; Identifikation mit dem Ort, der Region, der Nation, Europa und der Welt; Nationalstolz. Moral und Sexualität: moralische Einstellungen (Steuerhinterziehung, Diebstahl, Drogengebrauch, Lügen, Schmiergelder, Korruption, Euthanasie, Selbstmord, Umweltverschmutzung, Alkohol am Steuer; Skala); moralische Einstellungen zu Partnerschaft und Sexualität (Homosexualität, Abtreibung, Scheidung, Promiskuität; Skala); vermutete Verbreitung unmoralischer Verhaltensweisen in der Bevölkerung des Landes (Skala); Einstellung zu einer Bestrafung in Abhängigkeit von der Situation des Täters bzw. des Geschädigten (Skala). Demographie: Geschlecht; Geburtsjahr; Familienstand und Zusammenleben mit einem Partner; Kinderzahl; Schulbildung; Alter bei Beendigung der Schulausbildung; Berufstätigkeit; Vorgesetztenfunktion und Kontrollspanne; Betriebsgröße; Beruf (ISCO88) und berufliche Stellung; Dauer der Arbeitslosigkeit; Haushaltsgröße; Alter der Kinder im Haushalt; Haushaltsvorstand; Charakteristika des Haushaltsvorstands; Haushaltseinkommen. Der Fragebogen enthält weitere länderspezifische Fragen. Interviewerrating: Kooperationsbereitschaft des Befragten. Zusätzlich kodiert: Ortsgröße; Region; Datum des Interviews; Dauer des Interviews

Long range height variations in surface growth

This paper presents novel results obtained from numerical investigation of surfaces generated by the two-dimensional isotropic Kuramoto-Sivashinsky equation with an additional nonlinear term and a single independent parameter. Surface roughness exhibits a certain dependence on the system size that indicates power-law shape of the surface spectrum for small wave numbers. This leads to a conclusion that although cellular surface patterns of definite scale dominate in the range of short distances, there are also scale-free long-range height variations present in large systems. The dependence of the spectral exponent on the equation parameter gives new insight into the influence of the additional term in the equation on the scaling behavior for large systems

Digital Design and Fabrication within Technical and Economical Limitations

Today, designing in digital environment is far less limiting than the physical reality that the product will end up in - stresses and forces, physical material properties, manufacturing possibilities, economic considerations and etc. are to a large extent not present in digital design tools. With many of these being directly computable it would make sense to introduce these restrictions from the physical world to the digital design environment. By doing this with we could take account of the inevitable restrictions from the very initial design phases and considerations, hopefully enabling us to make better informed decisions and designs. Idag, designar i digitala miljön är betydligt mindre begränsande än den fysiska verkligheten att produkten kommer att hamna i - spänningar och krafter, fysikaliska materialegenskaper, tillverkningsmöjligheter, ekonomiska överväganden och etc. är i stor utsträckning inte finns i digitala designverktyg. Med många av dessa är direkt beräkningsbar det skulle vara meningsfullt att införa dessa restriktioner från den fysiska världen till den digitala designmiljö. Genom att göra detta med vi kunde ta hänsyn till de oundvikliga begränsningar från mycket ursprungliga utformning och överväganden, förhoppningsvis gör det möjligt för oss att fatta bättre underbyggda beslut och designer

Digital Design and Fabrication within Technical and Economical Limitations

Today, designing in digital environment is far less limiting than the physical reality that the product will end up in - stresses and forces, physical material properties, manufacturing possibilities, economic considerations and etc. are to a large extent not present in digital design tools. With many of these being directly computable it would make sense to introduce these restrictions from the physical world to the digital design environment. By doing this with we could take account of the inevitable restrictions from the very initial design phases and considerations, hopefully enabling us to make better informed decisions and designs. Idag, designar i digitala miljön är betydligt mindre begränsande än den fysiska verkligheten att produkten kommer att hamna i - spänningar och krafter, fysikaliska materialegenskaper, tillverkningsmöjligheter, ekonomiska överväganden och etc. är i stor utsträckning inte finns i digitala designverktyg. Med många av dessa är direkt beräkningsbar det skulle vara meningsfullt att införa dessa restriktioner från den fysiska världen till den digitala designmiljö. Genom att göra detta med vi kunde ta hänsyn till de oundvikliga begränsningar från mycket ursprungliga utformning och överväganden, förhoppningsvis gör det möjligt för oss att fatta bättre underbyggda beslut och designer