Characteristics of Control Laws Tested on the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

The Semi-Span Supersonic Transport (S4T) is an aeroelastically scaled wind-tunnel model built to test active controls concepts for large flexible supersonic aircraft in the transonic flight regime. It is one of several models constructed in the 1990's as part of the High Speed Research (HSR) Program. Control laws were developed for the S4T by M4 Engineering, Inc. and by Zona Technologies, Inc. under NASA Research Announcement (NRA) contracts. The model was tested in the NASA-Langley Transonic Dynamics Tunnel (TDT) four times from 2007 to 2010. The first two tests were primarily for plant identification. The third entry was used for testing control laws for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression. Whereas the third entry only tested FS subcritically, the fourth test demonstrated closed-loop operation above the open-loop flutter boundary. The results of the third entry are reported elsewhere. This paper reports on flutter suppression results from the fourth wind-tunnel test. Flutter suppression is seen as a way to provide stability margins while flying at transonic flight conditions without penalizing the primary supersonic cruise design condition. An account is given for how Controller Performance Evaluation (CPE) singular value plots were interpreted with regard to progressing open- or closed-loop to higher dynamic pressures during testing

Forestomach pH in hunted roe deer ( Capreolus capreolus ) in relation to forestomach region, time of measurement and supplemental feeding and comparison among wild ruminant species

There is a debate whether supplemental feeding of deer bears the risk of inducing health problems, in particular acidosis. Here, the pH values of forestomach contents of free-ranging roe deer (Capreolus capreolus) shot in areas with and without supplemental winter feeding were compared. pH was similar in the dorsal and ventral rumen, but lower at these sites than in the Atrium ruminis, where it was again lower than in the reticulum; this pattern corresponds to expectations based on differences in the presence of saliva at the different sites of the forestomach. pH was lower with increasing time that elapsed between death of the animal and measuring pH in unsupplemented animals and was lower in unsupplemented animals in May/June than later in the year. Animals with supplemental winter feeding had significantly lower rumen pH (5.5) than animals without food supplementation (5.7). These data suggest that supplemental feeding of roe deer has the potential to lower forestomach pH. Although pH values measured in supplemented animals in this study would be considered indicative of rumen acidosis in domestic cattle, they are within the range previously measured in various free-ranging Odocoilid species, including roe deer; were of a similar magnitude as the May/June values of unsupplemented roe deer in this study; and must be considered with respect to potentially rapid declines in pH between death of the animal and pH measurement. Given methodological problems, analyses of literature data from free-ranging wild ruminants provide little evidence for a systematic variation of rumen pH with feeding type and body mass, but lead to the hypothesis that some New World cervids, including the roe deer, might either naturally have lower pH values than other ruminants or rumen contents whose pH drops rapidly after deat

Prediction of Psilocybin Response in Healthy Volunteers

Responses to hallucinogenic drugs, such as psilocybin, are believed to be critically dependent on the user's personality, current mood state, drug pre-experiences, expectancies, and social and environmental variables. However, little is known about the order of importance of these variables and their effect sizes in comparison to drug dose. Hence, this study investigated the effects of 24 predictor variables, including age, sex, education, personality traits, drug pre-experience, mental state before drug intake, experimental setting, and drug dose on the acute response to psilocybin. The analysis was based on the pooled data of 23 controlled experimental studies involving 409 psilocybin administrations to 261 healthy volunteers. Multiple linear mixed effects models were fitted for each of 15 response variables. Although drug dose was clearly the most important predictor for all measured response variables, several non-pharmacological variables significantly contributed to the effects of psilocybin. Specifically, having a high score in the personality trait of Absorption, being in an emotionally excitable and active state immediately before drug intake, and having experienced few psychological problems in past weeks were most strongly associated with pleasant and mystical-type experiences, whereas high Emotional Excitability, low age, and an experimental setting involving positron emission tomography most strongly predicted unpleasant and/or anxious reactions to psilocybin. The results confirm that non-pharmacological variables play an important role in the effects of psilocybin

Association of eGFR-Related Loci Identified by GWAS with Incident CKD and ESRD

Family studies suggest a genetic component to the etiology of chronic kidney disease (CKD) and end stage renal disease (ESRD). Previously, we identified 16 loci for eGFR in genome-wide association studies, but the associations of these single nucleotide polymorphisms (SNPs) for incident CKD or ESRD are unknown. We thus investigated the association of these loci with incident CKD in 26,308 individuals of European ancestry free of CKD at baseline drawn from eight population-based cohorts followed for a median of 7.2 years (including 2,122 incident CKD cases defined as eGFR <60ml/min/1.73m2 at follow-up) and with ESRD in four case-control studies in subjects of European ancestry (3,775 cases, 4,577 controls). SNPs at 11 of the 16 loci (UMOD, PRKAG2, ANXA9, DAB2, SHROOM3, DACH1, STC1, SLC34A1, ALMS1/NAT8, UBE2Q2, and GCKR) were associated with incident CKD; p-values ranged from p = 4.1e-9 in UMOD to p = 0.03 in GCKR. After adjusting for baseline eGFR, six of these loci remained significantly associated with incident CKD (UMOD, PRKAG2, ANXA9, DAB2, DACH1, and STC1). SNPs in UMOD (OR = 0.92, p = 0.04) and GCKR (OR = 0.93, p = 0.03) were nominally associated with ESRD. In summary, the majority of eGFR-related loci are either associated or show a strong trend towards association with incident CKD, but have modest associations with ESRD in individuals of European descent. Additional work is required to characterize the association of genetic determinants of CKD and ESRD at different stages of disease progression

Vision Based Flexible Beam Tip Point Control

Because of the light weight and less wear and tear on components, the flexible beam has been and will continue to be an appealing option for civil and military applications. However, flexibility brings with it unwanted oscillations and severe chattering which may even lead to an unstable system. To tackle these challenges, a two-time scale controller is presented to track a desired tip point signal and at the same time mitigate the tip point vibration. To obtain more precise information of the tip point location and facilitate the easy extension to multiple-flexible-link problems, a camera is used to provide vision feedback in which the delayed vision signal is compensated by the state estimator and predictor. The controller is experimentally verified, and shown to exceed the performance of other tested controllers. © 2009 AACC

Vision Based Flexible Beam Tip Point Control

Because of the light weight and less wear and tear on components, the flexible beam/arm has been and will continue to be an appealing option for civil and military applications, such as space-based flexible manipulators. However, flexibility brings with it unwanted oscillations and severe chattering which may even lead to an unstable system. To tackle these challenges, a two-time scale controller is presented to track a desired tip point signal and at the same time mitigate the tip point vibration using direct vision feedback. In particular, an linear quadratic regulator (LQR) controller in the fast mode stabilizes the oscillations of the beam, and a boundary layer augmented sliding mode controller is proposed to track the desired position. To obtain more precise information of the tip point location and facilitate the easy extension to multiple-flexible-link problems, a camera is used to provide vision feedback in which the delayed vision signal is compensated by the state estimator and predictor. The vision data, which provides a direct measurement of the tip point, proves to be a better substitute for the more traditional strain gauge, which can only provide indirect measurements based on the mathematically derived mode shapes of the beam. The controller is experimentally verified, and shown to exceed the performance of other tested controllers. © 2009 IEEE

Antibacterial polyethylene/clay nanocomposites using chlorhexidine as organic modifier

The set of low density polyethylene/clay nanocomposites with increasing amount of organoclay nanofiller (3, 6 and 10 wt %) was prepared by melt compounding procedure without additives. An antimicrobial drug, chlorhexidine diacetate (CA), was loaded into Zn2+ form of clay mineral vermiculite (ZnVer) at very low concentration and then organoclay nanofiller CA/ZnVer was incorporated into polymeric matrix. The structural characteristics of all prepared samples were studied by XRD and FTIR techniques. The nanocomposites were tested for antibacterial activity against Staphylococcus aureus and Escherichia coli. Prepared samples showed a very good antibacterial activity with long lasting effect against S. aureus and slightly worse effect against E. coli.Web of Science2125224

Antibacterial LDPE nanocomposites based on zinc oxide nanoparticles/vermiculite nanofiller

Polyethylene (PE) nanocomposites with the zinc oxide-nanoparticles/vermiculite nanofiller were prepared in two-steps. In first step, the ZnO-np/V nanofiller were prepared by the mechanochemical method followed by a heat treatment at 650 A degrees C for 90 min. In second step, this nanofiller was used in concentration 3, 6, 10 and 15 wt% for PE nanocomposites preparation via melt compounding technique, the nanocomposites plates were pressed. The particles morphology of the ZnO-np/V nanofiller, arrangement of the ZnO-np/V nanofiller and surface of the PE plates were studied using scanning electron microscopy, optical light microscopy and atomic force microscopy. The surface roughness of the PE plates was evaluated from AFM measurements. Structural changes of the ZnO-np/V nanofiller in PE nanocomposites were monitored using X-ray diffraction analysis and Fourier transform infrared analysis. The gradual and long-term antibacterial effect of PE nanocomposites was tested on the Gram positive bacteria E. faecalis by counting the colony forming units number.Web of Science27499598