WorldWideScience

Sample records for axis vegf-flt-1 fms-like

  1. Soluble fms-like tyrosine kinase 1 promotes angiotensin II sensitivity in preeclampsia.

    Science.gov (United States)

    Burke, Suzanne D; Zsengellér, Zsuzsanna K; Khankin, Eliyahu V; Lo, Agnes S; Rajakumar, Augustine; DuPont, Jennifer J; McCurley, Amy; Moss, Mary E; Zhang, Dongsheng; Clark, Christopher D; Wang, Alice; Seely, Ellen W; Kang, Peter M; Stillman, Isaac E; Jaffe, Iris Z; Karumanchi, S Ananth

    2016-07-01

    Preeclampsia is a hypertensive disorder of pregnancy in which patients develop profound sensitivity to vasopressors, such as angiotensin II, and is associated with substantial morbidity for the mother and fetus. Enhanced vasoconstrictor sensitivity and elevations in soluble fms-like tyrosine kinase 1 (sFLT1), a circulating antiangiogenic protein, precede clinical signs and symptoms of preeclampsia. Here, we report that overexpression of sFlt1 in pregnant mice induced angiotensin II sensitivity and hypertension by impairing endothelial nitric oxide synthase (eNOS) phosphorylation and promoting oxidative stress in the vasculature. Administration of the NOS inhibitor l-NAME to pregnant mice recapitulated the angiotensin sensitivity and oxidative stress observed with sFlt1 overexpression. Sildenafil, an FDA-approved phosphodiesterase 5 inhibitor that enhances NO signaling, reversed sFlt1-induced hypertension and angiotensin II sensitivity in the preeclampsia mouse model. Sildenafil treatment also improved uterine blood flow, decreased uterine vascular resistance, and improved fetal weights in comparison with untreated sFlt1-expressing mice. Finally, sFLT1 protein expression inversely correlated with reductions in eNOS phosphorylation in placental tissue of human preeclampsia patients. These data support the concept that endothelial dysfunction due to high circulating sFLT1 may be the primary event leading to enhanced vasoconstrictor sensitivity that is characteristic of preeclampsia and suggest that targeting sFLT1-induced pathways may be an avenue for treating preeclampsia and improving fetal outcomes. PMID:27270170

  2. FMS-like tyrosine kinase 3 ligand treatment does not ameliorate experimental rapidly progressive glomerulonephritis.

    Directory of Open Access Journals (Sweden)

    Joanna R Ghali

    Full Text Available Fms-like tyrosine kinase 3-ligand (FL is a growth factor that may expand dendritic cell and regulatory T cell populations. We hypothesised that FL-induced regulatory T cells would protect mice from experimental rapidly progressive glomerulonephritis. To determine if FL was able to enhance regulatory T cell populations, C57BL/6 mice received 10 days of daily intraperitoneal injections of either FL or phosphate buffered saline. To induce accelerated autologous-phase anti-mouse glomerular basement membrane glomerulonephritis, mice were sensitized to sheep globulin 4 days prior to the induction of glomerulonephritis with sheep anti-mouse glomerular basement membrane globulin, and experiments ended 10 days later. FL was administered before, throughout and during the sensitization phase of this glomerulonephritis model. Renal disease and systemic immunity to the nephritogenic antigen were assessed. FL increased regulatory T cell and plasmacytoid dendritic cell proportions within spleen and lymph nodes. FL administration prior to glomerulonephritis did not protect mice from renal injury. When FL was given throughout the model, FL treated mice had reduced survival, with more interstitial neutrophils and glomerular CD11c+ cells than controls. Systemic immune responses showed increased IL-17A production from splenocytes, with more CD11c+ cells, but reduced plasmacytoid dendritic cell proportions in spleen and lymph nodes, despite increased regulatory T cell proportions. Under homeostatic conditions, FL expanded regulatory T cell and plasmacytoid dendritic cell populations, but FL enhanced systemic inflammatory responses and conventional dendritic cell populations when given during experimental glomerulonephritis, suggesting selective attempts to suppress pathogenic immunity by dendritic cell manipulation may be harmful.

  3. Fms-like tyrosine kinase-3 ligand alters antigen-specific responses to infections after severe burn injury

    OpenAIRE

    Bohannon, Julia; Fang, Geping; Cui, Weihua; Sherwood, Edward; Toliver-Kinsky, Tracy

    2009-01-01

    Burn patients are susceptible to opportunistic infections due partly to decreased immune functions, especially Th1-driven antigen-specific responses, which are regulated by dendritic cells. The dendritic cell growth factor, fms-like tyrosine kinase-3 ligand (FL), has been shown to increase resistance to P. aeruginosa, in a dendritic cell-dependent manner, in a mouse model of burn wound infection. The specific mechanisms of protection are not known. This study tested the hypothesis that FL can...

  4. Glyceryl Trinitrate Inhibits Hypoxia-Induced Release of Soluble fms-Like Tyrosine Kinase-1 and Endoglin from Placental Tissues

    OpenAIRE

    BARSOUM, IVRAYM B.; Renaud, Stephen J.; Graham, Charles H.

    2011-01-01

    Preeclampsia is associated with increased circulating levels of proinflammatory molecules, such as soluble fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng). On release by an inadequately perfused placenta into the maternal circulation, these molecules cause systemic endothelial dysfunction and the associated hypertension and proteinuria that characterize preeclampsia. We previously showed that glyceryl trinitrate (GTN) inhibits hypoxia/reoxygenation-induced apoptosis in the syn...

  5. Expression of the fms-like tyrosine kinase 4 gene becomes restricted to lymphatic endothelium during development.

    OpenAIRE

    Kaipainen, A; Korhonen, J; Mustonen, T; van Hinsbergh, V W; G. H. Fang; Dumont, D,; Breitman, M; Alitalo, K

    1995-01-01

    We have recently cloned the human fms-like tyrosine kinase 4 gene FLT4, whose protein product is related to two vascular endothelial growth factor receptors FLT1 and KDR/FLK1. Here the expression of FLT4 has been analyzed by in situ hybridization during mouse embryogenesis and in adult human tissues. The FLT4 mRNA signals first became detectable in the angioblasts of head mesenchyme, the cardinal vein, and extraembryonally in the allantois of 8.5-day postcoitus (p.c.) embryos. In 12.5-day p.c...

  6. Clonal evolution of AML on novel FMS-like tyrosine kinase-3 (FLT3 inhibitor therapy with evolving actionable targets

    Directory of Open Access Journals (Sweden)

    Pashtoon M. Kasi

    2016-01-01

    Full Text Available For acute myeloid leukemia (AML, identification of activating mutations in the FMS-like tyrosine kinase-3 (FLT3 has led to the development of several FLT3-inhibitors. Here we present clinical and next generation sequencing data at the time of progression of a patient on a novel FLT3-inhibitor clinical trial (ASP2215 to show that employing therapeutic interventions with these novel targeted therapies can lead to consequences secondary to selective pressure and clonal evolution of cancer. We describe novel findings alongside data on treatment directed towards actionable aberrations acquired during the process. (Clinical Trial: NCT02014558; registered at: 〈https://clinicaltrials.gov/ct2/show/NCT02014558〉

  7. Maternal soluble fms-like tyrosine kinase-1, placental growth factor, plasminogen activator inhibitor-2, and folate concentrations and early fetal size : the Generation R study

    NARCIS (Netherlands)

    Bouwland-Both, Marieke I.; Steegers, Eric A. P.; Lindemans, Jan; Russcher, Henk; Hofman, Albert; Geurts-Moespot, Anneke J.; Sweep, Fred C. G. J.; Jaddoe, Vincent W. V.; Steegers-Theunissen, Regine P. M.

    2013-01-01

    OBJECTIVE: Fetal growth is dependent on adequate development of the placenta. Impaired angiogenesis and vasculogenesis in early pregnancy compromises placental and embryonic development. The proteins soluble fms-like tyrosine kinase (sFlt)-1, placental growth factor (PlGF), and plasminogen activator

  8. Increased serum levels of anti-angiogenic factors soluble fms-like tyrosine kinase and soluble endoglin in sickle cell disease

    NARCIS (Netherlands)

    Landburg, P P; Elsenga, H; Schnog, J B; Duits, A J

    2008-01-01

    The anti-angiogenic factors soluble fms-like tyrosine kinase (sFlt)-1 and soluble endoglin (sEng) have been shown to be of importance in angiogenesis by sequestering and inhibiting vascular endothelial growth factor, placenta-like growth factor and transforming growth factor-beta(1) signaling. Given

  9. Suppressed Production of Soluble Fms-Like Tyrosine Kinase-1 Contributes to Myocardial Remodeling and Heart Failure.

    Science.gov (United States)

    Seno, Ayako; Takeda, Yukiji; Matsui, Masaru; Okuda, Aya; Nakano, Tomoya; Nakada, Yasuki; Kumazawa, Takuya; Nakagawa, Hitoshi; Nishida, Taku; Onoue, Kenji; Somekawa, Satoshi; Watanabe, Makoto; Kawata, Hiroyuki; Kawakami, Rika; Okura, Hiroyuki; Uemura, Shiro; Saito, Yoshihiko

    2016-09-01

    Soluble fms-like tyrosine kinase-1 (sFlt-1), an endogenous inhibitor of vascular endothelial growth factor and placental growth factor, is involved in the pathogenesis of cardiovascular disease. However, the significance of sFlt-1 in heart failure has not been fully elucidated. We found that sFlt-1 is decreased in renal failure and serves as a key molecule in atherosclerosis. In this study, we aimed to investigate the role of the decreased sFlt-1 production in heart failure, using sFlt-1 knockout mice. sFlt-1 knockout mice and wild-type mice were subjected to transverse aortic constriction and evaluated after 7 days. The sFlt-1 knockout mice had significantly higher mortality (52% versus 15%; P=0.0002) attributable to heart failure and showed greater cardiac hypertrophy (heart weight to body weight ratio, 8.95±0.45 mg/g in sFlt-1 knockout mice versus 6.60±0.32 mg/g in wild-type mice; Pfailure through upregulation of monocyte chemoattractant protein-1 expression in pressure-overloaded heart. PMID:27480835

  10. In vivo evidence for an instructive role of fms-like tyrosine kinase-3 (FLT3) ligand in hematopoietic development.

    Science.gov (United States)

    Tsapogas, Panagiotis; Swee, Lee Kim; Nusser, Anja; Nuber, Natko; Kreuzaler, Matthias; Capoferri, Giuseppina; Rolink, Hannie; Ceredig, Rhodri; Rolink, Antonius

    2014-04-01

    Cytokines are essential regulators of hematopoiesis, acting in an instructive or permissive way. Fms-like tyrosine kinase 3 ligand (FLT3L) is an important cytokine for the development of several hematopoietic populations. Its receptor (FLT3) is expressed on both myeloid and lymphoid progenitors and deletion of either the receptor or its ligand leads to defective developmental potential of hematopoietic progenitors. In vivo administration of FLT3L promotes expansion of progenitors with combined myeloid and lymphoid potential. To investigate further the role of this cytokine in hematopoietic development, we generated transgenic mice expressing high levels of human FLT3L. These transgenic mice displayed a dramatic expansion of dendritic and myeloid cells, leading to splenomegaly and blood leukocytosis. Bone marrow myeloid and lymphoid progenitors were significantly increased in numbers but retained their developmental potential. Furthermore, the transgenic mice developed anemia together with a reduction in platelet numbers. FLT3L was shown to rapidly reduce the earliest erythroid progenitors when injected into wild-type mice, indicating a direct negative role of the cytokine on erythropoiesis. We conclude that FLT3L acts on multipotent progenitors in an instructive way, inducing their development into myeloid/lymphoid lineages while suppressing their megakaryocyte/erythrocyte potential. PMID:24463214

  11. Fms-like Tyrosine Kinase (FLT) 3 and FLT3 Internal Tandem Duplication in Different Types of Adult Leukemia: Analysis of 147 Patients

    OpenAIRE

    Peng, Hong-ling; Zhang, Guang-Sen; Gong, Fan-Jie; Shen, Jian-Kai; Zhang, Yang; Xu, Yun-Xiao; Zheng, Wen-Li; Dai, Chong-Wen; Pei, Min-Fei; YANG, JUN-JIE

    2008-01-01

    Aim To assess the expression level of fms-like tyrosine kinase 3 (FLT3), the incidence of FLT3/internal tandem duplications (ITD) mutation, and prognostic value of FLT3 changes in different types of adult leukemia. Methods Bone marrow mononuclear cells were isolated from 147 adult patients with leukemia. Reverse transcriptase polymerase chain reaction (PCR) was used to screen FLT3/ITD mutation and quantitative PCR was performed to evaluate the expression of the FLT3 transcri...

  12. Murine germinal center B cells require functional Fms-like tyrosine kinase 3 signaling for IgG1 class-switch recombination.

    Science.gov (United States)

    Svensson, Mattias N D; Andersson, Karin M E; Wasén, Caroline; Erlandsson, Malin C; Nurkkala-Karlsson, Merja; Jonsson, Ing-Marie; Brisslert, Mikael; Bemark, Mats; Bokarewa, Maria I

    2015-12-01

    Switched antibody classes are important for efficient immune responses. Aberrant antibody production to otherwise harmless antigens may result in autoimmunity. The protein kinase fms-like tyrosine kinase 3 receptor (Flt3) has an important role during early B-cell development, but the role of Flt3 in peripheral B cells has not been assessed before. Herein we describe a previously unappreciated role for Flt3 in IgG1 class-switch recombination (CSR) and production. We show that Flt3 is reexpressed on B-cell lymphoma 6(+) germinal center B cells in vivo and following LPS activation of peripheral B cells in vitro. Absence of Flt3 signaling in Flt3 ligand-deficient mice results in impaired IgG1 CSR and accumulation of IgM-secreting plasma cells. On activated B cells, Flt3 is coexpressed and functions in synergy with the common-gamma chain receptor family. B cells from Flt3 ligand-deficient mice have impaired IL-4R signaling, with reduced phosphorylation of signal transducer and activator of transcription (Stat) 6, and demonstrate a failure to initiate CSR to IgG1 with low expression of γ1 germ-line transcripts, resulting in impaired IgG1 production. Thus, functional synergy between Flt3 and IL-4R signaling is critical for Stat-mediated regulation of sterile γ1 germ-line transcripts and CSR to IgG1. PMID:26627255

  13. Soluble fms-like tyrosine kinase-1 and vascular endothelial growth factor:Novel markers for unexplained early recurrent pregnancy loss

    Institute of Scientific and Technical Information of China (English)

    Mahmoud Fathy; Hassan

    2014-01-01

    Objective:To evaluate the role of soluble fms-like tyrosine kinase-1(sFlt-1) and vascular endothelial growth factor(VEGF) for prediction of pregnancy loss in patients with history of unexplained early recurrent pregnancy loss(RPL).Methods:A prospective case control study was conducted in42 women with history of unexplained earlyRPL, and170 pregnant controls with history of uncomplicated pregnancy.We measured maternal serum sFlt-1 andVEGF at gestational age6-9 weeks as predictor for pregnancy loss.Results:Mean serum levels of sFlt-1 andVEGF were significantly higher inRPL group than controls(10439.7±385.4vs3304.5±104.8;P<0.0001, for sFlt-1, and1885.0±98.3 vs709.8±24.8;P<0.0001, forVEGF).Receiver operating characteristic(ROC) curves analyses established that sFlt-1 andVEGF were able to discriminate women at risk of developing pregnancy loss with area underROC curve0.970 for sFlt-1 and0.953 forVEGF.Cutoff value of5159.5 pg/mL for sFlt-1 was predictor for early pregnancy loss with 95.2% sensitivity,91.2% specificity, and odds ratio(OR)206 [95%confidence interval(CI),45.4-941].Cutoff value of915.5 pg/mL forVEGF was predictor for early pregnancy loss with92.9% sensitivity,90.6% specificity, andOR125 [95%CI:34.7-451].Conclusion:These data advocate a relationship between sFlt-1,VEGF, andRPL suggesting that the high levels of sFlt-1 andVEGF might be associated with the pathogenesis ofRPL.

  14. Soluble fms-like tyrosine kinase-1 and endothelial adhesion molecules (intercellular cell adhesion molecule-1 and vascular cell adhesion molecule-1) as predictive markers for blood pressure reduction after renal sympathetic denervation.

    Science.gov (United States)

    Dörr, Oliver; Liebetrau, Christoph; Möllmann, Helge; Gaede, Luise; Troidl, Christian; Rixe, Johannes; Hamm, Christian; Nef, Holger

    2014-05-01

    Renal sympathetic denervation (RSD) is a treatment option for patients with resistant arterial hypertension, but in some patients it is not successful. Predictive parameters on the success of RSD remain unknown. The angiogenic factors soluble fms-like tyrosine kinase-1 (sFLT-1), intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) are known to be associated with endothelial dysfunction, vascular remodeling, and hypertension. We evaluated whether sFLT-1, ICAM-1, and VCAM-1 are predictive markers for blood pressure reduction after RSD. Consecutive patients (n=55) undergoing renal denervation were included. Venous serum samples for measurement of sFlt-1, ICAM-1, and VCAM-1 were collected before and 6 months after RSD. A therapeutic response was defined as an office systolic blood pressure reduction of >10 mm Hg 6 months after RSD. A significant mean office systolic blood pressure reduction of 31.2 mm Hg was observed in 46 patients 6 months after RSD. Nine patients were classified as nonresponders, with a mean systolic blood pressure reduction of 4.6 mm Hg. At baseline, sFLT-1 levels were significantly higher in responders than in nonresponders (P<0.001) as were ICAM-1 (P<0.001) and VCAM-1 levels (P<0.01). The areas under the curve for sFLT-1, ICAM-1, and VCAM-1 were 0.82 (interquartile range, 0.718-0.921; P<0.001), 0.754 (0.654-0.854; P<0.001), and 0.684 (0.564-804; P=0.01), respectively, demonstrating prediction of an RSD response. Responders showed significantly higher serum levels of sFLT-1, ICAM-1, and VCAM-1 at baseline compared with nonresponders. Thus, this study identified for the first time potential biomarkers with a predictive value indicating a responder or nonresponder before renal denervation. PMID:24470464

  15. 补肾安胎冲剂对复发性流产患者血清血管内皮生长因子及其可溶性受体-1的影响%Effects of Granules for Tonifying Kidney and Preventing Miscarriage on Serum Levels of Vascular Endothelial Growth Factor and Soluble Fms-like Tyrosine Kinase-1 in Patients with Recurrent Spontaneous Abortion

    Institute of Scientific and Technical Information of China (English)

    李伟莉; 胡瑞华

    2013-01-01

    目的 探讨补肾安胎冲剂治疗复发性流产(recurrent spontaneous abortion,RSA)的机制.方法 采用酶联免疫吸附法检测30例RSA患者治疗前后及30例正常早孕妇女血清血管内皮生长因子(vascular endothelial growth factor,VEGF)及其受体--可溶性fms样酪氨酸激酶-1(soluble fms-like tyrosine kinase-1,sFlt-1)的水平.结果 治疗组妊娠成功率为80.0%;与对照组比较,治疗组治疗前血清VEGF显著降低(P<0.01),sFlt-1显著增高(P<0.01);治疗组治疗后与治疗前比较,VEGF显著升高(P<0.01),sFlt-1显著降低(P<0.01);保胎治疗无效者与保胎治疗成功者比较,血清VEGF水平显著降低(P<0.01),血清sFlt-1水平显著增高(P<0.05).结论 补肾安胎冲剂治疗RSA的机制可能与提高血清VEGF水平,降低血清sFlt-1水平,从而促进胎盘绒毛血管的形成有关.%Objective To investigate the mechanism by -which Granules for tonifying the kidney and preventing miscarriage exert therapeutic effect in patients with recurrent spontaneous abortion (RSA). Methods Thirty RSA patients (as treatment group) and 30 women with normal early pregnancy (as control group) were included in this study. Enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of vascular endothelial growth factor (VEGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) before and after treatment with the granules for tonifying the kidney and preventing miscarriage. Results The success rate of pregnancy was 80. 00% in the treatment group. Before treatment, the treatment group had significantly lower serum VEGF level and significantly higher serum sFlt-1 level than the control group (P

  16. Diagnosis of preeclampsia with soluble Fms-like tyrosine kinase 1/placental growth factor ratio

    DEFF Research Database (Denmark)

    Andersen, Louise Bjørkholt; Frederiksen-Møller, Britta; Work Havelund, Kathrine;

    2015-01-01

    The angiogenic factor ratio soluble Fms-kinase 1 (sFlt-1)/placental growth factor (PlGF) is a novel diagnostic tool for preeclampsia. We compared the efficacy of the KRYPTOR (BRAHMS) automated assays for sFlt-1 and PlGF with the Elecsys (Roche) assays in a routine clinical setting. Preeclamptic...... women (n = 39) were included shortly after the time of diagnosis. Normotensive control pregnancies were matched by gestational age (n = 76). The KRYPTOR assays performed comparably or superior to Elecsys (sFlt-1/PlGF area under the curve 0.746 versus 0.735; P = .09; for non-obese 0.820 versus 0.805, P...... = .047). For early-onset preeclampsia, KRYPTOR area under the curve increased to 0.929 with a 100% specificity for preeclampsia at cut-off 85 and an 88.9% sensitivity for preeclampsia at cut-off 33. For women with preeclampsia and preterm delivery or Hemolysis, Elevated Liver enzymes, Low Platelet count...

  17. Triple axis spectrometers

    International Nuclear Information System (INIS)

    Conventional triple-axis neutron spectroscopy was developed by Brockhouse over thirty years ago' and remains today a versatile and powerful tool for probing the dynamics of condensed matter. The original design of the triple axis spectrometer is technically simple and probes momentum and energy space on a point-by-point basis. This ability to systematically probe the scattering function in a way which only requires a few angles to be moved under computer control and where the observed data in general can be analysed using a pencil and graph paper or a simple fitting routine, has been essential for the success of the method. These constraints were quite reasonable at the time the technique was developed. Advances in computer based data acquisition, neutron beam optics, and position sensitive area detectors have been gradually implemented on many triple axis spectrometer spectrometers, but the full potential of this has not been fully exploited yet. Further improvement in terms of efficiency (beyond point by point inspection) and increased sensitivity (use of focusing optics whenever the problem allows it) could easily be up to a factor of 10-20 over present instruments for many problems at a cost which is negligible compared to that of increasing the flux of the source. The real cost will be in complexity - finding the optimal set-up for a given scan and interpreting the data as the they are taken. On-line transformation of the data for an appropriate display in Q, ω space and analysis tools will be equally important for this task, and the success of these new ideas will crucially depend on how well we solve these problems. (author)

  18. Preferred axis in cosmology

    CERN Document Server

    Zhao, Wen

    2016-01-01

    The foundation of modern cosmology relies on the so-called cosmological principle which states an homogeneous and isotropic distribution of matter in the universe on large scales. However, recent observations, such as the temperature anisotropy of the cosmic microwave background (CMB) radiation, the motion of galaxies in the universe, the polarization of quasars and the acceleration of the cosmic expansion, indicate preferred directions in the sky. If these directions have a cosmological origin, the cosmological principle would be violated, and modern cosmology should be reconsidered. In this paper, by considering the preferred axis in the CMB parity violation, we find that it coincides with the preferred axes in CMB quadrupole and CMB octopole, and they all align with the direction of the CMB kinematic dipole. In addition, the preferred directions in the velocity flows, quasar alignment, anisotropy of the cosmic acceleration, the handedness of spiral galaxies, and the angular distribution of the fine-structu...

  19. Three axis attitude control system

    Science.gov (United States)

    Studer, Philip A. (Inventor)

    1988-01-01

    A three-axis attitude control system for an orbiting body comprised of a motor driven flywheel supported by a torque producing active magnetic bearing is described. Free rotation of the flywheel is provided about its central axis and together with limited angular torsional deflections of the flywheel about two orthogonal axes which are perpendicular to the central axis. The motor comprises an electronically commutated DC motor, while the magnetic bearing comprises a radially servoed permanent magnet biased magnetic bearing capable of producing cross-axis torques on the flywheel. Three body attitude sensors for pitch, yaw and roll generate respective command signals along three mutually orthogonal axes (x, y, z) which are coupled to circuit means for energizing a set of control coils for producing torques about two of the axes (x and y) and speed control of the flywheel about the third (z) axis. An energy recovery system, which is operative during motor deceleration, is also included which permits the use of a high-speed motor to perform effectively as a reactive wheel suspended in the magnetic bearing.

  20. Easy axis switching in magnetite

    International Nuclear Information System (INIS)

    The easy magnetic axis switching in magnetite is investigated. Magnetization data confirmed activation character of the process with activation energy of the same order as that of the Verwey transition, suggesting common origin. On the other hand this activation energy rises with pressure (up to 1.2GPa), unlike TV. The axis switching is clearly reflected in field dependence of resistivity and the direct structural data showed that it is simultaneous with the reorganization of structure. Thus, control of the structure can be possible with the application of magnetic field, as in shape memory materials. Finally, NMR showed that all, possibly decoupled entities: lattice distortion and charge and orbital orderings, change simultaneously while the axis switching occurs.

  1. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  2. Two-axis angular effector

    International Nuclear Information System (INIS)

    A new class of coplanar two-axis angular effectors is described. These effectors combine a two-axis rotational joint analogous to a Cardan joint with linear actuators in a manner to produce a wider range of rotational motion about both axes defined by the joint. This new class of effectors also allows design of robotic manipulators having very high strength and efficiency. These effectors are particularly suited for remote operation in unknown surroundings, because of their extraordinary versatility. An immediate application is to the problems which arise in nuclear waste remediation. 11 figs

  3. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  4. Vertical axis wind turbine acoustics

    OpenAIRE

    Pearson, Charlie

    2014-01-01

    Increasing awareness of the issues of climate change and sustainable energy use has led to growing levels of interest in small-scale, decentralised power generation. Small-scale wind power has seen significant growth in the last ten years, partly due to the political support for renewable energy and the introduction of Feed In Tariffs, which pay home owners for generating their own electricity. Due to their ability to respond quickly to changing wind conditions, small-scale vertical axis...

  5. Hypothalamus-Pituitary-Thyroid Axis.

    Science.gov (United States)

    Ortiga-Carvalho, Tania M; Chiamolera, Maria I; Pazos-Moura, Carmen C; Wondisford, Fredic E

    2016-01-01

    The hypothalamus-pituitary-thyroid (HPT) axis determines the set point of thyroid hormone (TH) production. Hypothalamic thyrotropin-releasing hormone (TRH) stimulates the synthesis and secretion of pituitary thyrotropin (thyroid-stimulating hormone, TSH), which acts at the thyroid to stimulate all steps of TH biosynthesis and secretion. The THs thyroxine (T4) and triiodothyronine (T3) control the secretion of TRH and TSH by negative feedback to maintain physiological levels of the main hormones of the HPT axis. Reduction of circulating TH levels due to primary thyroid failure results in increased TRH and TSH production, whereas the opposite occurs when circulating THs are in excess. Other neural, humoral, and local factors modulate the HPT axis and, in specific situations, determine alterations in the physiological function of the axis. The roles of THs are vital to nervous system development, linear growth, energetic metabolism, and thermogenesis. THs also regulate the hepatic metabolism of nutrients, fluid balance and the cardiovascular system. In cells, TH actions are mediated mainly by nuclear TH receptors (210), which modify gene expression. T3 is the preferred ligand of THR, whereas T4, the serum concentration of which is 100-fold higher than that of T3, undergoes extra-thyroidal conversion to T3. This conversion is catalyzed by 5'-deiodinases (D1 and D2), which are TH-activating enzymes. T4 can also be inactivated by conversion to reverse T3, which has very low affinity for THR, by 5-deiodinase (D3). The regulation of deiodinases, particularly D2, and TH transporters at the cell membrane control T3 availability, which is fundamental for TH action. © 2016 American Physiological Society. Compr Physiol 6:1387-1428, 2016. PMID:27347897

  6. Introductory lecture on triple-axis spectrometer

    International Nuclear Information System (INIS)

    Triple-axis spectrometer is a multi-purpose instrument for powder neutron diffraction, single crystal neutron diffraction, powder inelastic neutron scattering, single crystal inelastic neutron scattering, and neutron polarization analysis. In this lecture how to use the triple-axis spectrometer is explained for the beginners. (author)

  7. Identification of kinematic errors of five-axis machine tool trunnion axis from finished test piece

    Science.gov (United States)

    Zhang, Ya; Fu, Jianzhong; Chen, Zichen

    2014-09-01

    Compared with the traditional non-cutting measurement, machining tests can more accurately reflect the kinematic errors of five-axis machine tools in the actual machining process for the users. However, measurement and calculation of the machining tests in the literature are quite difficult and time-consuming. A new method of the machining tests for the trunnion axis of five-axis machine tool is proposed. Firstly, a simple mathematical model of the cradle-type five-axis machine tool was established by optimizing the coordinate system settings based on robot kinematics. Then, the machining tests based on error-sensitive directions were proposed to identify the kinematic errors of the trunnion axis of cradle-type five-axis machine tool. By adopting the error-sensitive vectors in the matrix calculation, the functional relationship equations between the machining errors of the test piece in the error-sensitive directions and the kinematic errors of C-axis and A-axis of five-axis machine tool rotary table was established based on the model of the kinematic errors. According to our previous work, the kinematic errors of C-axis can be treated as the known quantities, and the kinematic errors of A-axis can be obtained from the equations. This method was tested in Mikron UCP600 vertical machining center. The machining errors in the error-sensitive directions can be obtained by CMM inspection from the finished test piece to identify the kinematic errors of five-axis machine tool trunnion axis. Experimental results demonstrated that the proposed method can reduce the complexity, cost, and the time consumed substantially, and has a wider applicability. This paper proposes a new method of the machining tests for the trunnion axis of five-axis machine tool.

  8. Axis intersection measurement of three-axis turntable with two crosshair targets

    Institute of Scientific and Technical Information of China (English)

    REN Shun-qing; MA Guang-cheng; WANG Chang-hong

    2005-01-01

    In order to measure three-axis intersection error, two crosshair targets were fixed in the inner axis frame of a three-axis turntable. Also a theodolite was used to point its telescope to the targets and to measure the horizontal angles when three axes were on equi-spaced angle positions. The calculation equations of the axis intersection were deduced from the mounting position of the theodolite, positions of two targets, angular positions of three axes, and the measured horizontal angles with the theodolite. Finally, a practical measurement is carried out on a horizontal three-axis turntable and error analysis is conducted.

  9. An Elevated Maternal Plasma Soluble fms-Like Tyrosine Kinase-1 to Placental Growth Factor Ratio at Midtrimester Is a Useful Predictor for Preeclampsia

    Directory of Open Access Journals (Sweden)

    Mahmoud Fathy Hassan

    2013-01-01

    Full Text Available Background. To assess the ability of mid-trimester sFlt-1/PlGF ratio for prediction of preeclampsia in two different Arabic populations. Methods. This study measured levels of sFlt-1, PlGF, and sFlt-1/PlGF ratio at midtrimester in 83 patients who developed preeclampsia with contemporary 250 matched controls. Results. Women subsequently developed preeclampsia had significantly lower PlGF levels and higher sFlt-1 and sFlt-1/PlGF ratio levels than women with normal pregnancies (P<0.0001 for all. Women who with preterm preeclampsia had significantly higher sFlt-1 and sFlt-1/PlGF ratio than term preeclamptic women (P=0.01, 0.003, resp.. A cutoff value of 3198 pg/mL for sFlt-1 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 88%, 83.6%, and 84.7%, respectively, with odds ratio (OR 37.2 [95% confidence interval (CI 17.7–78.1]. PIGF at cutoff value of 138 pg/mL was able to predict preeclampsia with sensitivity, specificity, and accuracy of 85.5%, 77.2%, and 79.3%, respectively, with OR 20 [95% CI, 10.2–39.5]. The sFlt-1/PIGF ratio at cutoff value of 24.5 was able to predict preeclampsia with sensitivity, specificity, and accuracy of 91.6%, 86.4%, and 87.7%, respectively with OR 67 [95% CI, 29.3–162.1]. Conclusion. Midtrimester sFlt-1/PlGF ratio displayed the highest sensitivity, specificity, accuracy, and OR for prediction of preeclampsia, demonstrating that it may stipulate more effective prediction of preeclampsia development than individual factor assay.

  10. Fms like tyrosine kinase (FLT3) and nucleophosmin 1 (NPM1) mutations in de novo normal karyotype acute myeloid leukemia (AML).

    Science.gov (United States)

    Dunna, Nageswara Rao; Rajappa, Senthil; Digumarti, Raghunadharao; Vure, Sugunakar; Kagita, Sailaja; Damineni, Surekha; Rao, V R; Yadav, Satish Kumar; Ravuri, Rajasekhara Reddy; Satti, Vishnupriya

    2010-01-01

    Mutations in FLT3 and NPM1 are important prognostic factors in AML, influencing outcome in normal karyotype cases. We here analysed incidences of FLT3/ITD, D 835 and NPM1 mutations in patients with de novo normal karyotype AML using PCR and gene sequencing, along with laboratory parameters and treatment outcomes. There were 128 patients with a median age of 45 years (range, 19-65). FLT3/ITD mutations were detected in 26 (20.3%), FLT3/D835 in 8 (6.2%) and NPM1 in 22 (17.1%). The incidence of FLT3/ITD was higher in those with elevated lactate dehydrogenase (LDH) and peripheral blasts (p=< 0.002, < 0.001) while NPM1 mutations or both NPM1 and FLT3/ITD was more common in elevated total leukocyte counts (TLC), LDH and peripheral blasts (p=<0.0001). Complete response and disease free survival were lower in those with FLT3/ITD mutations (p=0.04, 0.03). The incidence of FLT3 and NPM1 mutations was found to be low in Indian patients with normal karyotype AML. PMID:21338238

  11. Design of off-axis PIAACMC mirrors

    Science.gov (United States)

    Pluzhnik, Eugene; Guyon, Olivier; Belikov, Ruslan; Bendek, Eduardo

    2015-09-01

    The Phase-Induced Amplitude Apodization Complex Mask Coronagraph (PIAACMC) provides an efficient way to control diffraction propagation effects caused by the central obstruction/segmented mirrors of the telescope. PIAACMC can be optimized in a way that takes into account both chromatic diffraction effects caused by the telescope obstructed aperture and tip/tilt sensitivity of the coronagraph. As a result, unlike classic PIAA, the PIAACMC mirror shapes are often slightly asymmetric even for an on-axis configuration and require more care in calculating off-axis shapes when an off-axis configuration is preferred. A method to design off-axis PIAA mirror shapes given an on-axis mirror design is presented. The algorithm is based on geometrical ray tracing and is able to calculate off-axis PIAA mirror shapes for an arbitrary geometry of the input and output beams. The method is demonstrated using the third generation PIAACMC design for WFIRST-AFTA telescope. Geometrical optics design issues related to the off-axis diffraction propagation effects are also discussed.

  12. New Urban Vertical Axis Wind Turbine Design

    OpenAIRE

    Alexandru-Mihai CISMILIANU; Alexandru BOROS; Ionut-Cosmin ONCESCU; Florin FRUNZULICA

    2015-01-01

    This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT) have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades) following the rules of bi...

  13. Plasma stabilization in traps with spatial axis

    International Nuclear Information System (INIS)

    Possible methods of plasma stabilization within traps with spatial axis for both circular and triangular-elliptic magnetic surfaces, applicable to Dracon, Spitzer's Eight and Heliac, are studied theoretically. (author). 18 refs, 5 figs

  14. Axis of Zodiacal light Near Tropic Cancer

    CERN Document Server

    Nawar, S; Mikhail, J S; Morcos, A B; Ibrahim, Alhassan I

    2014-01-01

    The axis of zodiacal lights have been obtained in blue and yellow colors using photoelectric observations of zodiacal light. These observations have been carried out at Abu Simbel Site in Egypt, in October 1975. This site lies too near to the tropic of Cancer, at which the axis of the zodiacal light cone perpendiculars to the horizon. The results show that the plane of the zodiacal light is inclined to the normal by 1.59 degrees in blue color and 1.18 degrees in yellow color. This means that there is a slight variation in zodiacal light axis with wavelength, and the axis almost coincide with the ecliptic. The present results for blue color can be considered as the first one in the world near the tropic of Cancer.

  15. UMAPRM: Uniformly sampling the medial axis

    KAUST Repository

    Yeh, Hsin-Yi Cindy

    2014-05-01

    © 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of Cspace. We Theoretically analyze The distribution generated by UMAPRM and show its uniformity. Our results show That UMAPRM\\'s distribution of samples along The medial axis is not only uniform but also preferable To other medial axis samplers in certain planning problems. We demonstrate That UMAPRM has negligible computational overhead over other sampling Techniques and can solve problems The others could not, e.g., a bug Trap. Finally, we demonstrate UMAPRM successfully generates higher clearance paths in The examples.

  16. Actuator assembly including a single axis of rotation locking member

    Science.gov (United States)

    Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.

    2009-12-08

    An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.

  17. [Leptin and hypothalamus-hypophysis-thyroid axis].

    Science.gov (United States)

    Riccioni, G; Menna, V; Lambo, M S; Della Vecchia, R; Di Ilio, C; De Lorenzo, A; D'Orazio, N

    2004-01-01

    The leptin system is a major regulator of food intake and metabolic rate. The leptin, an adipose tissue hormone whose plasma levels reflect energy stores, plays an important rule in the pathogenesis of such eating disorders like bulimia and anorexia. Thyroid hormones are major regulators of energy homeostasis. It is possible that leptin and thyroid hormone exert their actions on thermogenesis and energy metabolism via the same common effector patways. Leptin influences feedback regulation of the hypotalamic TRH-secreting neurons by thyroid hormone. Low serum levels of thyroid hormones reflect a dysfunction of the hypotalamic-pituitary-thyroid (HPT) and hypotalamic-pituitary-adrenal (HPA) axis in patients with nervosa anorexia. Neuroendocrine effects of leptin include effects on the HPT and HPA axis. The aim of this work is to evaluated the interactions between leptina and HPT axis on the basis of recent published works and reviews in literature. PMID:15147079

  18. New Urban Vertical Axis Wind Turbine Design

    Directory of Open Access Journals (Sweden)

    Alexandru-Mihai CISMILIANU

    2015-12-01

    Full Text Available This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades following the rules of biplane airplanes. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally and justify the new proposed design.

  19. Diffuser Augmented Horizontal Axis Tidal Current Turbines

    Directory of Open Access Journals (Sweden)

    Nasir Mehmood

    2012-09-01

    Full Text Available The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The tidal energy industry is undergoing an increasing shift towards diffuser augmented turbines. The reason is the higher power output of diffuser augmented turbines compared to conventional open turbines. The purpose of this study is to present a comprehensive review of diffuser augmented horizontal axis tidal current turbines. The components, relative advantages, limitations and design parameters of diffuser augmented horizontal axis tidal current turbines are presented in detail. CFD simulation of NACA 0016 airfoil is carried out to explore its potential for designing a diffuser. The core issues associated with diffuser augmented horizontal axis tidal current turbines are also discussed.

  20. Modular off-axis solar concentrator

    Energy Technology Data Exchange (ETDEWEB)

    Plesniak, Adam P; Hall, John C

    2015-01-27

    A solar concentrator including a housing defining a vertical axis and including a receiving wall connected to a reflecting wall to define an internal volume and an opening into the internal volume, wherein the reflecting wall defines at least one primary optical element, and wherein at least a portion of the reflecting wall includes a layer of reflective material, the housing further including a cover connected to the receiving wall and the reflecting wall to seal the opening, and at least one receiver mounted on the receiving wall such that a vertical axis of the receiver is disposed at a non-zero angle relative to the vertical axis of the housing, the receiver including at least one photovoltaic cell.

  1. Aeroelastically coupled blades for vertical axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  2. Solar rotating magnetic dipole?. [around axis perpendicular to rotation axis of the sun

    Science.gov (United States)

    Antonucci, E.

    1974-01-01

    A magnetic dipole rotating around an axis perpendicular to the rotation axis of the sun can account for the characteristics of the surface large-scale solar magnetic fields through the solar cycle. The polarity patterns of the interplanetary magnetic field, predictable from this model, agree with the observed interplanetary magnetic sector structure.

  3. Generator design for vertical axis wind turbine

    OpenAIRE

    Schüller, Espen Samuelsen

    2010-01-01

    The optimization process for generators are often done for rated speeds and torques. This thesis will discuss and show optimization of a vertical axis wind turbine generator that has a given wind profile. Although the rated power of the turbine is at winds of about 10 m/s, the wind is mostly at 4-6 m/s, thus needing a generator that has high efficiencies also at lower speeds and torques.Vertical axis wind turbine does not use blade pitching as the horizontal ones do and the torque and speed c...

  4. Lift Augmentation for Vertical Axis Wind Turbines

    OpenAIRE

    Gerald M Angle II; Mary Ann Clarke

    2010-01-01

    The concept of harnessing wind power has been around for centuries, and is first recorded by the Persians in 900 AD. These early uses of wind power were for the processing of food, particularly grinding grains, and consisted of stationary blades around a horizontal axis, the precursor to today’s horizontal axis wind turbines (HAWT). Technology for these wind mills was essentially the same until the 1930’s when advances in aircraft propeller theories were applied to the blades of the turbine. ...

  5. Research of misalignment between dithered ring laser gyro angle rate input axis and dither axis

    Science.gov (United States)

    Li, Geng; Wu, Wenqi; FAN, Zhenfang; LU, Guangfeng; Hu, Shaomin; Luo, Hui; Long, Xingwu

    2014-12-01

    The strap-down inertial navigation system (SINS), especially the SINS composed by dithered ring laser gyroscope (DRLG) is a kind of equipment, which providing high reliability and performance for moving vehicles. However, the mechanical dither which is used to eliminate the "Lock-In" effect can cause vibration disturbance to the INS and lead to dithering coupling problem in the inertial measurement unit (IMU) gyroscope triad, so its further application is limited. Among DRLG errors between the true gyro rotation rate and the measured rotation rate, the frequently considered one is the input axis misalignment between input reference axis which is perpendicular to the mounting surface and gyro angular rate input axis. But the misalignment angle between DRLG dither axis and gyro angular rate input axis is often ignored by researchers, which is amplified by dither coupling problem and that would lead to negative effects especially in high accuracy SINS. In order to study the problem more clearly, the concept of misalignment between DRLG dither axis and gyro angle rate input axis is researched. Considering the error of misalignment is of the order of 10-3 rad. or even smaller, the best way to measure it is using DRLG itself by means of an angle exciter as an auxiliary. In this paper, the concept of dither axis misalignment is explained explicitly firstly, based on this, the frequency of angle exciter is induced as reference parameter, when DRLG is mounted on the angle exciter in a certain angle, the projections of angle exciter rotation rate and mechanical oscillation rate on the gyro input axis are both sensed by DRLG. If the dither axis has misalignment error with the gyro input axis, there will be four major frequencies detected: the frequency of angle exciter, the dither mechanical frequency, sum and difference frequencies of the former two frequencies. Then the amplitude spectrum of DRLG output signal obtained by the using LabVIEW program. if there are only angle

  6. The Trading Axis in Irkutsk Downtown

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2015-12-01

    Full Text Available The article reveals a linear concentration of the trading function in the historical center of Irkutsk. It features historical prerequisites and continuation of the tradition in the post-Soviet period, given the conversion of plants and factories. The article analyses the current state and prospects of modernization of the trading axis with its transformation into a modern public space.

  7. Resolution of a triple axis spectrometer

    DEFF Research Database (Denmark)

    Nielsen, Mourits; Bjerrum Møller, Hans

    A new method for obtaining the resolution function for a triple-axis neutron spectrometer is described, involving a combination of direct measurement and analytical calculation. All factors which contribute to the finite resolution of the instrument may be taken into account, and Gaussian or...

  8. Triple-axis spectrometer DruechaL

    International Nuclear Information System (INIS)

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs

  9. Fibrous dysplasia in axis treated with vertebroplasty

    Directory of Open Access Journals (Sweden)

    Kadir Kotil

    2010-01-01

    Full Text Available Vertebroplasty of the axis is a challenging procedure, and little is known about its therapeutic outcome. Cervical fibrous dysplasia with a distinct cyst is a rare entity and few cases have been reported in the literature. A 55-year-old man with fibrous dysplasia of axis presented with severe neck pain and left arm since six months. Computed tomography and magnetic resonance imaging revealed an expansile, destructive lesion involving the axis, and no spinal cord. He was submitted to retropharyngeal surgery and the lesion was fulled by vertebroplasty. Microscopic examination was consistent with the diagnosis of monostotic fibrous dysplasia. After the surgery no recurrence was observed. The patient had remarkable improvement in clinical relief of neck pain at 1-year follow-up. Although there are descriptions of vertebral fibrous dysplasia, this is the 13th case of monostotic fibrous dysplasia of the cervical spine, and the 3rd case of the axis described in the literature. The unique case who had treated with ope vertebroplasty.

  10. Horizontal Axis Levitron--A Physics Demonstration

    Science.gov (United States)

    Michaelis, Max M.

    2014-01-01

    After a brief history of the Levitron, the first horizontal axis Levitron is reported. Because it is easy to operate, it lends itself to educational physics experiments and analogies. Precession and nutation are visualized by reflecting the beam from a laser pointer off the "spignet". Precession is fundamental to nuclear magnetic…

  11. Thyroid axis alterations in childhood obesity.

    Science.gov (United States)

    Gertig, Anna M; Niechciał, Elżbieta; Skowrońska, Bogda

    2012-01-01

    In recent years researchers have become increasingly interested in the particular relation between the function of the thyroid gland and the body mass in the population of obese children. Numerous studies have been conducted and the literature on the related issues has been abounding. Several thereof have strived at pinpointing a significant link between the function of the thyroid axis and the body mass. Yet, it still remains to be clarified whether these subtle changes in the level of thyroid hormones and TSH observed in childhood obesity are responsible for the increased body mass or rather they represent a secondary phenomenon. The mechanism most often put forward by the researchers that links obesity to thyroid function is the increased level of leptin, which affects neurones in the hypothalamus and the thyroid axis causing TRH and TSH secretion. The body mass is positively correlated with serum leptin and elevated level of leptin is connected with an increase in TSH level. However, there is still controversy whether these inconspicuous differences observed in thyroid axis merit the treatment with thyroxine since these changes seem to constitute a consequence rather than a cause of obesity. Therefore, as most authors postulate, primary importance should be placed on lifestyle changes and body weight reduction leaving substitutive treatment as a supplementary option. The purpose of this review is to present the most current issues on child obesity and the related malfunction of the thyroid axis through an overview of international publications from the years 1996-2011. PMID:23146791

  12. Tennis Rackets and the Parallel Axis Theorem

    Science.gov (United States)

    Christie, Derek

    2014-01-01

    This simple experiment uses an unusual graph straightening exercise to confirm the parallel axis theorem for an irregular object. Along the way, it estimates experimental values for g and the moment of inertia of a tennis racket. We use Excel to find a 95% confidence interval for the true values.

  13. Triple-axis spectrometer DruechaL

    Energy Technology Data Exchange (ETDEWEB)

    Buehrer, W.; Keller, P. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    DruechaL is a triple-axis spectrometer located at a cold guide. The characteristics of guide and instrument allow the use of a broad spectral range of neutrons. The resolution in momentum and energy transfer can be tuned to match the experimental requirements by using either collimators or focusing systems (monochromator, antitrumpet, analyser). (author) figs., tabs., refs.

  14. Vortex capturing vertical axis wind turbine

    International Nuclear Information System (INIS)

    An analytical-numerical study is presented for an innovative lift vertical axis turbine whose blades are designed with vortex trapping cavities that act as passive flow control devices. The unsteady flow field past one-bladed and two-bladed turbines is described by a combined analytical and numerical method based on conformal mapping and on a blob vortex method

  15. Multi-Axis Accelerometer Calibration System

    Science.gov (United States)

    Finley, Tom; Parker, Peter

    2010-01-01

    A low-cost, portable, and simplified system has been developed that is suitable for in-situ calibration and/or evaluation of multi-axis inertial measurement instruments. This system overcomes facility restrictions and maintains or improves the calibration quality for users of accelerometer-based instruments with applications in avionics, experimental wind tunnel research, and force balance calibration applications. The apparatus quickly and easily positions a multi-axis accelerometer system into a precisely known orientation suitable for in-situ quality checks and calibration. In addition, the system incorporates powerful and sophisticated statistical methods, known as response surface methodology and statistical quality control. These methods improve calibration quality, reduce calibration time, and allow for increased calibration frequency, which enables the monitoring of instrument stability over time.

  16. Local Pancake Defeats Axis of Evil

    OpenAIRE

    Vale, Chris

    2005-01-01

    Among the biggest surprises revealed by COBE and confirmed by WMAP measurements of the temperature anisotropy of the CMB are the anomalous features in the 2-point angular correlation function on very large angular scales. In particular, the $\\ell = 2$ quadrupole and $\\ell = 3$ octopole terms are surprisingly planar and aligned with one another, which is highly unlikely for a statistically isotropic Gaussian random field, and the axis of the combined low-$\\ell$ signal is perpendicular to eclip...

  17. Parking Strategies for Vertical Axis Wind Turbines

    OpenAIRE

    2012-01-01

    Strategies for parking a vertical axis wind turbine at storm load are considered. It is proposed that if a directly driven permanent magnet synchronous generator is used, an elegant choice is to short-circuit the generator at storm, since this makes the turbine efficiently damped. Nondamped braking is found to be especially problematic for the case of two blades where torsional oscillations may imply thrust force oscillations within a range of frequencies.

  18. Turbulence in vertical axis wind turbine canopies

    OpenAIRE

    Kinzel, Matthias; Araya, Daniel B.; Dabiri, John O.

    2015-01-01

    Experimental results from three different full scale arrays of vertical-axis wind turbines (VAWTs) under natural wind conditions are presented. The wind velocities throughout the turbine arrays are measured using a portable meteorological tower with seven, vertically staggered, three-component ultrasonic anemometers. The power output of each turbine is recorded simultaneously. The comparison between the horizontal and vertical energy transport for the different turbine array sizes shows the i...

  19. Methamphetamine and the hypothalamic-pituitary-adrenal axis

    OpenAIRE

    Zuloaga, Damian G.; Jacosbskind, Jason S.; Raber, Jacob

    2015-01-01

    Psychostimulants such as methamphetamine (MA) induce significant alterations in the function of the hypothalamic-pituitary-adrenal (HPA) axis. These changes in HPA axis function are associated with altered stress-related behaviors and might contribute to addictive processes such as relapse. In this mini-review we discuss acute and chronic effects of MA (adult and developmental exposure) on the HPA axis, including effects on HPA axis associated genes/proteins, brain regions, and behaviors such...

  20. Horizontal axis Levitron—a physics demonstration

    Science.gov (United States)

    Michaelis, Max M.

    2014-01-01

    After a brief history of the Levitron, the first horizontal axis Levitron is reported. Because it is easy to operate, it lends itself to educational physics experiments and analogies. Precession and nutation are visualized by reflecting the beam from a laser pointer off the ‘spignet’. Precession is fundamental to nuclear magnetic resonance, magnetic resonance imaging, particle traps and the movement of bodies in space. Longitudinal and lateral bounce behaviour is explained via ‘the principle of gentle superposition’ of two traps: the micro-precessional and the macro-trap. Theory is initiated. Scaling experiments are mentioned. Industrial applications might follow. Patent pending.

  1. A Portable Single Axis Magnetic Gradiometer

    DEFF Research Database (Denmark)

    Merayo, José M.G.; Petersen, Jan Raagaard; Nielsen, Otto V;

    2001-01-01

    The single axis magnetic gradiometer based on two compact detector compensation (CDC) fluxgate ringcore sensors separated 20 cm is described. Despite its high stability and precision better than 1 nT, the calibration procedures are not straightforward. Firstly, the mono-axial measurement does...... not provide vector information about the magnetic field. Secondly, one of the sensors measures the ambient magnetic field and is used to compensate for the main field at both sensors. Several methods have been developed for characterization of the 2 gradiometer, and the calibration of the gradient...

  2. Pulsed 3-Axis Vector SERF Magnetometer

    Science.gov (United States)

    Hedges, Morgan; Romalis, Michael

    2016-05-01

    We demonstrate a 3-axis atomic vector magnetometer operating in the SERF regime, using a single beam path, and capable of operating in Earth's field using field feedback. It has similar sensitivity along all 3 axes that is fundamentally limited by photon and atom shot noise. The scheme uses a high intensity pump pulse to polarize Rb atoms in ~ 1 μs and a sequence of magnetic field pulses applied while the atoms are monitored during free precession. The sequence used provides minimal sensitivity to pulse errors, while also allowing unambiguous discrimination between external magnetic fields and misalignment between laser and magnetic coil axes.

  3. Optimisation of vertical axis wind turbines

    OpenAIRE

    Roynarin, Wirachai

    2004-01-01

    A practical Vertical Axis Wind Turbine (VAWTs) based on a Darrieus rotor has been designed and tested and found to be capable of self-starting at wind speeds above 4m/s. The self-start feature has been achieved by replacing the usual symmetrical aerofoil blade in the VAWT rotor and by using a concentric Savonius rotor or semi-cylinder turbine. A computer program was produced to compute the power coefficient versus tip speed ratio characteristics of a selected aerofoil profile employed in a VA...

  4. Equilibrium calculations for helical axis stellarators

    International Nuclear Information System (INIS)

    An average method based on a vacuum flux coordinate system is presented. This average method permits the study of helical axis stellarators with toroidally dominated shifts. An ordering is introduced, and to lowest order the toroidally averaged equilibrium equations are reduced to a Grad-Shafranov equation. Also, to lowest order, a Poisson-type equation is obtained for the toroidally varying corrections to the equilibium. By including these corrections, systems that are toroidally dominated, but with significant helical distortion to the equilibrium, may be studied. Numerical solutions of the average method equations are shown to agree well with three-dimensional calculations

  5. Single-axis gyroscopic motion with uncertain angular velocity about spin axis

    Science.gov (United States)

    Singh, S. N.

    1977-01-01

    A differential game approach is presented for studying the response of a gyro by treating the controlled angular velocity about the input axis as the evader, and the bounded but uncertain angular velocity about the spin axis as the pursuer. When the uncertain angular velocity about the spin axis desires to force the gyro to saturation a differential game problem with two terminal surfaces results, whereas when the evader desires to attain the equilibrium state the usual game with single terminal manifold arises. A barrier, delineating the capture zone (CZ) in which the gyro can attain saturation and the escape zone (EZ) in which the evader avoids saturation is obtained. The CZ is further delineated into two subregions such that the states in each subregion can be forced on a definite target manifold. The application of the game theoretic approach to Control Moment Gyro is briefly discussed.

  6. VERITAS: Versatile Triple-Axis Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Il

    2006-04-15

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, {approx} 5 m Curved Guide, {approx} 26 m w/ R 1500 m Straight Guide before the Instrument, {approx} 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world.

  7. VERITAS: Versatile Triple-Axis Spectrometer

    International Nuclear Information System (INIS)

    Korea Atomic Energy Research Institute is planning to build a cold neutron triple-axis spectrometer at HANARO, the 30 MW research reactor. The spectrometer is expected to be completed in 2008 with the following configuration from the upstream to the downstream. Guide Supermirror m = 2, In-pile Straight Section, ∼ 5 m Curved Guide, ∼ 26 m w/ R 1500 m Straight Guide before the Instrument, ∼ 40 m Filters PG and Be Neutron Velocity Selector (Future) Monochromators Vertically Focusing Monochromators PG(002) and Heusler(111) Doubly Focusing Monochromators (Future) Monochromator-Sample Distance 2 m Collimation C1 Soller Collimators, 20', 40' 80'Beam Height at the Sample Table 1.5 m Sample-Analyzer Distance 1.0 m Collimation C2 Soller Collimators, 20', 40', 80' Radial Collimator Analyzers Horizontally Focusing Analyzers w/ Fixed Vertical Focusing PG(002) and Heusler(111) Analyzer-Detector Distance 0.5 m Detectors 5 cm Tube Detector 25 cm wide Position Sensitive Detector Once completed, the neutron flux at sample is expected to surpass that of SPINS at NCNR, making this instrument one of the most powerful 2nd generation cold neutron triple-axis spectrometers in the world

  8. Computer Assisted Mechanical Axis and Kinematic TKA

    Science.gov (United States)

    McEwen, Peter; Mahoharan, Varaguna

    2016-01-01

    Introduction: Total knee arthroplasty (TKA) has traditionally been and largely continues to be aligned mechanically, that being with a neutral coronal plane mechanical tibiofemoral axis and a joint line orientated at 900 to this axis. Femoral component rotation is set by gap balancing or by externally rotating 30 from any of a number femoral reference lines. This produces a rectangular flexion gap and relaxes patellar tracking. Kinematic alignment (KA) is an alternative technique that aims to restore premorbid alignment, joint orientation and ligament tension. The basic premise for this technique is based on evidence that the medial and lateral femoral condyles consistently equate to cylinders of equal or near equal size and that therefore with a fixed radius, cruciate retaining implant, matched distal femoral, posterior femoral and proximal tibial resections, accounting for bone and cartilage already lost will reproduce the premorbid joint line and restore native premorbid kinematics. Femoral rotation is therefore referenced off the prearthritic posterior condylar axis (PCA) that is on average internally rotated to the AP axis. Kinematic alignment therefore has the potential to challenge patellar tracking, increase patellar load and potentially increase patellar complications. Method: Case control study – level of evidence III-2. Between November 2012 and June 2013 the senior author completed 104 consecutive computer assisted (CAS) kinematically aligned total knee arthroplasties (TKA) with a cruciate retaining, fixed bearing, single radius implant. The results of these surgeries were compared with the results of 91 consecutive CAS mechanically aligned TKA done between November 2011 and October 2012 using the same navigation system and implant Implant sizing and positioning as well as gap measurement and ligament balance was done with computer assistance in all cases. Data was collected prospectively and analysed retrospectively. Results: The Oxford Knee Score

  9. Lift Augmentation for Vertical Axis Wind Turbines

    Directory of Open Access Journals (Sweden)

    Gerald M Angle II

    2010-12-01

    Full Text Available The concept of harnessing wind power has been around for centuries, and is first recorded by the Persians in 900 AD. These early uses of wind power were for the processing of food, particularly grinding grains, and consisted of stationary blades around a horizontal axis, the precursor to today’s horizontal axis wind turbines (HAWT. Technology for these wind mills was essentially the same until the 1930’s when advances in aircraft propeller theories were applied to the blades of the turbine. During this development period, which has since remained basically unchanged, the design push was for increasingly larger propellers requiring heavy and costly transmissions, generators, and support towers to be installed. An alternative concept to the HAWT was developed by Georges Darrieus [5], which utilized a vertical shaft and is known as a vertical axis wind turbine (VAWT. The scientific development of the concept did not gain strong attention until the 1970’s due to the perceived low efficiency of this style. This perception was due in part to the portion of the blade’s rotary path that is adverse to the generation of power. This efficiency loss can be minimized by the mechanical movement of the blade, relative to the airflow during the upwind portion of the blades’ rotational path. Since, circulation control can alter the forces generated by an airfoil, it could be used to increase the efficiency of a VAWT by increasing the torque produced on the downwind portion of the path, while removing the need for a physical change in angle of attack. With the recent upturn in petroleum costs and global warming concerns, interest in renewable energy technologies have been reinvigorated, in particular the desire for advanced wind energy technologies, including the application of lift augmentation techniques. One of these techniques is to utilize circulation control to enhance the lifting capacity of the blades based on the location of the blade in the

  10. Model for performance prediction in multi-axis machining

    CERN Document Server

    Lavernhe, Sylvain; Lartigue, Claire; 10.1007/s00170-007-1001-4

    2009-01-01

    This paper deals with a predictive model of kinematical performance in 5-axis milling within the context of High Speed Machining. Indeed, 5-axis high speed milling makes it possible to improve quality and productivity thanks to the degrees of freedom brought by the tool axis orientation. The tool axis orientation can be set efficiently in terms of productivity by considering kinematical constraints resulting from the set machine-tool/NC unit. Capacities of each axis as well as some NC unit functions can be expressed as limiting constraints. The proposed model relies on each axis displacement in the joint space of the machine-tool and predicts the most limiting axis for each trajectory segment. Thus, the calculation of the tool feedrate can be performed highlighting zones for which the programmed feedrate is not reached. This constitutes an indicator for trajectory optimization. The efficiency of the model is illustrated through examples. Finally, the model could be used for optimizing process planning.

  11. Five-axis rough machining for impellers

    Institute of Scientific and Technical Information of China (English)

    Ruolong QI; Weijun LIU; Hongyou BIAN; Lun LI

    2009-01-01

    The most important components used in aero-space, ships, and automobiles are designed with free form surfaces. An impeller is one of the most important components that is difficult to machine because of its twisted blades. Rough machining is recognized as the most crucial procedure influencing machining efficiency and is critical for the finishing process. An integrated rough machining course with detailed algorithms is presented in this paper. An algorithm for determining the minimum distance between two surfaces is applied to estimate the tool size. The space between two blades that will be cleared from the roughcast is divided to generate CC points. The tool axis vector is confirmed based on flank milling using a simple method that could eliminate global interference between the tool and the blades. The result proves that the machining methodology presented in this paper is useful and successful.

  12. Polarized triple-axis spectrometer TASP

    Energy Technology Data Exchange (ETDEWEB)

    Boeni, P.; Keller, P. [Lab. for Neutron Scattering ETH Zurich, Zurich (Switzerland) and Paul Scherrer Institute, Villigen (Switzerland)

    1996-11-01

    The polarized triple-axis spectrometer TASP at SINQ has been optimized for measuring magnetic cross sections in condensed matter. The neutrons are polarized or analyzed either by means of benders or Heusler monochromators. The beam divergence, i.e. the intensity, and the spectral range of the neutrons is rather large because of the supermirror coatings of the feeding neutron guide. The intensity can be further increased at the sample position by means of a focussing monochromator and a focussing anti-trumpet. The end position of TASP allows the tailoring of the neutron beam already before the monochromator and to scatter neutrons over very wide ranges of angles. (author) 6 figs., 1 tab., 8 refs.

  13. H3837 DARHT's first dual-axis shot

    International Nuclear Information System (INIS)

    Test H3837 was the first explosive shot performed in front of both flash x-ray axes at the Los Alamos Dual Axis Radiographic HydroTest (DARHT) facility. Executed in November 2009, the shot was an explosively-driven metal flyer plate in a series of experiments designed to explore equation-of-state properties of shocked materials. With high-strength steel walls over half an inch thick, the boom box confined the shot completely without taxing the penetrating capability of the DARHT x-ray beams; in addition, over three inches of tungsten attenuation in the beamlines prevented saturation of the camera systems. The boombox was staged within the DACS (Dual Axis Confinement system) with a source-to-object distance of 1.33 m for each Axis; radiographic magnifications were 4 and 4.5 for Axes I and II respectively. The first Axis provided a pulse of 60 ns width and dose 450 R at 1 m, while the second Axis provided four pulses of the following widths and doses: 20 ns, 85 R; 45 ns, 169 R; 65 ns, 233 R; 65 ns, 225 R; beam spot sizes were measured (50% MTF LANL definition) as < 1.7 mm (Axis I) and 1.9-2.8 mm (Axis II), with less than 1.5 mm beam motion between Axis II pulses. The Bucky Grid camera system was used for Axis I, while Axis II had a unique four-frame camera developed jointly by MIT Lincoln Laboratory. Imaging the initial shock wave traveling through the flyer plate, DARHT Axis II captured the range of motion from the shock front emergence in the flyer to breakout at the free surface; the Axis I pulse provided a perpendicular perspective of the shot at a time coinciding with the third pulse of Axis II. Shock speed in the material and other time-dependent properties such as material damage progression are measured using the time-evolved data from Axis II, while density reconstructions are made from the views of Axes I and II. The radiographs from Axis I and Axis II pulse 3 are compared in order to generate a three-dimensional image of the shocked material, enabling

  14. A comparison of on-axis and off-axis heliostat alignment strategies

    Energy Technology Data Exchange (ETDEWEB)

    Jones, S.A.

    1996-03-01

    Heliostat installation and alignment costs will be an important element in future solar power tower projects. The predicted annual performances of on- and-off axis strategies are compared for 95 m{sup 2} flat-glass heliostats and an external, molten-salt receiver. Actual approaches to heliostat alignment that have been used in the past are briefly discussed, and relative strengths and limitations are noted. The optimal approach can vary with the application.

  15. Suicidal events among pathological gamblers: the role of comorbidity of axis I and axis II disorders.

    Science.gov (United States)

    Bischof, Anja; Meyer, Christian; Bischof, Gallus; John, Ulrich; Wurst, Friedrich Martin; Thon, Natasha; Lucht, Michael; Grabe, Hans Joergen; Rumpf, Hans-Juergen

    2015-02-28

    The risk for suicidal ideation and suicide attempts among pathological gamblers is high compared to the general population. Little is known about the interplay of Axis I and Axis II disorders, severity of gambling disorder, and suicidal ideation and suicide attempts. The study aims to address this linkage. The sampling design of the study "Pathological Gambling and Epidemiology" (PAGE) included four recruitment channels: general population, gambling locations, project telephone hotline, and in-patient treatment for pathological gambling. A total of 442 study participants with lifetime pathological gambling received a clinical interview. The multivariate analysis showed mood disorders (Relative Risk Ratio, RRR=5.14, 95%-Confidence Interval, CI=2.91-9.07), substance use disorders (RRR=1.73, CI=1.02-2.94), and early onset of gambling disorder (RRR=0.96, CI=0.93-0.99) to be associated with suicidal ideation. Suicidal attempts were associated with female sex (RRR=3.58, CI=1.56-8.19), mood disorders (RRR=11.92, CI=4.70-30.26), and Cluster B personality disorders (RRR=2.40, CI=1.13-5.10). Among study participants with suicide attempts, more had a Cluster B personality disorder than among participants with ideation solely (RRR=3.08, CI=1.48-6.40). Among this large mixed sample of pathological gamblers, high proportions of individuals with suicidal events, multi-morbidity on Axis I, and a strong linkage to Cluster B personality disorders were found. PMID:25537488

  16. Iklan pada Provider AXIS dan TELKOMSEL di Televisi

    OpenAIRE

    Simatupang, Perdana Tua

    2015-01-01

    Perdana Tua Simatupang. Communication Science. The title of the study is “AXIS and TELKOMSEL provider Television Commercial”. The goal of this study is to see the communication advertisement by AXIS and TELKOMSEL provider through television commercial. This study is using communication advertising theory and television commercial theory. Analysis used is single table data analysis and analytic hierarchy process(AHP). The object of the study is AXIS provider television commercial “Group Hug” v...

  17. Analysis and design of a vertical axis wind turbine

    OpenAIRE

    Goyena Iriso, Joseba

    2011-01-01

    The main objective of this project is to design a new vertical axis wind turbine, specifically one Giromill wind turbine. The project development requires performing a previous study of the vertical axis wind turbines currently development. This study has to be performed before starting to design the wind turbine. Other very important aim is the development of a new vertical axis wind turbine. The after analyses that will result in the final design of the wind turbine will b...

  18. Energy Efficient Hybrid Dual Axis Solar Tracking System

    OpenAIRE

    Rashid Ahammed Ferdaus; Mahir Asif Mohammed; Sanzidur Rahman; Sayedus Salehin; Mohammad Abdul Mannan

    2014-01-01

    This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanical single axis to a hybrid dual axis. For optimizing the solar tracking mechanism electromechanical systems were evolved through implementation of different evolutional algorithms and methodologies. To present the tracker, a hybrid dual-axis solar tracking system is designed, built, and tested based on both the solar map and light sensor based continuous tracking mechanism. Th...

  19. Semiactive Vibration Control for Horizontal Axis Washing Machine

    OpenAIRE

    Barış Can Yalçın; Haluk Erol

    2015-01-01

    A semiactive vibration control method is developed to cope with the dynamic stability problem of a horizontal axis washing machine. This method is based on adjusting the maximum force values produced by the semiactive suspension elements considering a washing machine’s vibration data (three axis angular position and three axis angular acceleration values in time). Before actuation signals are received by the step motors of the friction dampers, vibration data are evaluated, and then, the step...

  20. The multi-axis vibration environment and man.

    Science.gov (United States)

    Lovesey, E J

    1970-12-01

    Many investigations into the effects of vibration on man have been performed since Mallock's first study of London Underground vibrations in 1902. The vibration research has tended to be confined to the vertical (heave) axis, yet recent experiments have indicated that low frequency vibration along the lateral (sway) axis has a greater adverse effect upon comfort and performance. Measurements of the vibration environments in current forms of transport including motor vehicles, hovercraft and aircraft etc have shown that appreciable quantities of vibration along all three axes exist. Further vibration research should consider the effects of multi-axis vibrations upon man rather than limit tests to single axis vibration. PMID:15676336

  1. Neuroactive steroids and stress axis regulation: Pregnancy and beyond.

    Science.gov (United States)

    Brunton, Paula J

    2016-06-01

    The hypothalamo-pituitary-adrenal (HPA) axis plays a critical role in regulating responses to stress and long term dysregulation of the HPA axis is associated with higher rates of mood disorders. There are circumstances where the HPA axis is more or less responsive to stress. For example, during late pregnancy ACTH and corticosterone responses to stress are markedly suppressed, whereas in offspring born to mothers that experienced repeated stress during pregnancy, the HPA axis is hyper-responsive to stress. Neuroactive steroids such as allopregnanolone, tetrahydrodeoxycorticosterone (THDOC) and androstanediol can modulate HPA axis activity and concentrations of some neuroactive steroids in the brain are altered during pregnancy and following stress. Thus, here altered neurosteroidogenesis is proposed as a mechanism that could underpin the dynamic changes in HPA axis regulation typically observed in late pregnant and in prenatally stressed individuals. In support of this hypothesis, evidence in rats demonstrates that elevated levels of allopregnanolone in pregnancy induce a central inhibitory opioid mechanism that serves to minimize stress-induced HPA axis activity. Conversely, in prenatally stressed rodents, where HPA axis stress responses are enhanced, evidence indicates the capacity of the brain for neurosteroidogenesis is reduced. Understanding the mechanisms involved in adaptations in HPA axis regulation may provide insights for manipulating stress sensitivity and for developing therapies for stress-related disorders in humans. PMID:26259885

  2. Comparison of long-axis and short-axis PROPELLER-EPI for diffusion-weighted magnetic resonance imaging; Vergleich von Long-Axis- und Short-Axis-PROPELLER-EPI fuer die diffusionsgewichtete Magnetresonanztomographie

    Energy Technology Data Exchange (ETDEWEB)

    Rossbach, Matthias; Jochimsen, Thies H.; Herrmann, Karl-Heinz; Ros, Christian; Guellmar, Daniel; Reichenbach, Juergen R. [Jena Univ. Hospital (Germany). Medical Physics Group

    2011-07-01

    Echo planar imaging (EPI) in combination with PROPELLER allows high-resolution diffusion-weighted imaging. In this study, the image quality of short-axis and long-axis PROPELLER was compared and optimized using phantom and in vivo data. Furthermore, diffusion-weighted measurements using both sequences were compared with those of a reference sequence. It was found that the long-axis sequence provided better image quality, whereas the results of the diffusion weighted measurements were more accurate with the short-axis variant, and that the results of the diffusion weighted measurements of both sequences agreed well with those of the reference sequence. (orig.)

  3. Microbiota and the gut-brain axis.

    Science.gov (United States)

    Bienenstock, John; Kunze, Wolfgang; Forsythe, Paul

    2015-08-01

    Changes in gut microbiota can modulate the peripheral and central nervous systems, resulting in altered brain functioning, and suggesting the existence of a microbiota gut-brain axis. Diet can also change the profile of gut microbiota and, thereby, behavior. Effects of bacteria on the nervous system cannot be disassociated from effects on the immune system since the two are in constant bidirectional communication. While the composition of the gut microbiota varies greatly among individuals, alterations to the balance and content of common gut microbes may affect the production of molecules such as neurotransmitters, e.g., gamma amino butyric acid, and the products of fermentation, e.g., the short chain fatty acids butyrate, propionate, and acetate. Short chain fatty acids, which are pleomorphic, especially butyrate, positively influence host metabolism by promoting glucose and energy homeostasis, regulating immune responses and epithelial cell growth, and promoting the functioning of the central and peripheral nervous systems. In the future, the composition, diversity, and function of specific probiotics, coupled with similar, more detailed knowledge about gut microbiota, will potentially help in developing more effective diet- and drug-based therapies. PMID:26175487

  4. Yaw dynamics of horizontal axis wind turbines

    Science.gov (United States)

    Hansen, A. C.

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw-controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they know they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  5. Yaw dynamics of horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, A.C. (Utah Univ., Salt Lake City, UT (United States))

    1992-05-01

    Designers of a horizontal axis wind turbine yaw mechanism are faced with a difficult decision. They know that if they elect to use a yaw- controlled rotor then the system will suffer increased initial cost and increased inherent maintenance and reliability problems. On the other hand, if they elect to allow the rotor to freely yaw they known they will have to account for unknown and random, though bounded, yaw rates. They will have a higher-risk design to trade-off against the potential for cost savings and reliability improvement. The risk of a yaw-free system could be minimized if methods were available for analyzing and understanding yaw behavior. The complexity of yaw behavior has, until recently, discouraged engineers from developing a complete yaw analysis method. The objectives of this work are to (1) provide a fundamental understanding of free-yaw mechanics and the design concepts most effective at eliminating yaw problems, and (2) provide tested design tools and guidelines for use by free-yaw wind systems manufacturers. The emphasis is on developing practical and sufficiently accurate design methods.

  6. Turbulence in vertical axis wind turbine canopies

    Science.gov (United States)

    Kinzel, Matthias; Araya, Daniel B.; Dabiri, John O.

    2015-11-01

    Experimental results from three different full scale arrays of vertical-axis wind turbines (VAWTs) under natural wind conditions are presented. The wind velocities throughout the turbine arrays are measured using a portable meteorological tower with seven, vertically staggered, three-component ultrasonic anemometers. The power output of each turbine is recorded simultaneously. The comparison between the horizontal and vertical energy transport for the different turbine array sizes shows the importance of vertical transport for large array configurations. Quadrant-hole analysis is employed to gain a better understanding of the vertical energy transport at the top of the VAWT arrays. The results show a striking similarity between the flows in the VAWT arrays and the adjustment region of canopies. Namely, an increase in ejections and sweeps and decrease in inward and outward interactions occur inside the turbine array. Ejections are the strongest contributor, which is in agreement with the literature on evolving and sparse canopy flows. The influence of the turbine array size on the power output of the downstream turbines is examined by comparing a streamwise row of four single turbines with square arrays of nine turbine pairs. The results suggest that a new boundary layer forms on top of the larger turbine arrays as the flow adjusts to the new roughness length. This increases the turbulent energy transport over the whole planform area of the turbine array. By contrast, for the four single turbines, the vertical energy transport due to turbulent fluctuations is only increased in the near wake of the turbines. These findings add to the knowledge of energy transport in turbine arrays and therefore the optimization of the turbine spacing in wind farms.

  7. Gut-liver axis and sensing microbes.

    Science.gov (United States)

    Szabo, Gyongyi; Bala, Shashi; Petrasek, Jan; Gattu, Arijeet

    2010-01-01

    'Detoxification' of gut-derived toxins and microbial products from gut-derived microbes is a major role of the liver. While the full repertoire of gut-derived microbial products that reach the liver in health and disease is yet to be explored, the levels of bacterial lipopolysaccharide (LPS), a component of Gram-negative bacteria, is increased in the portal and/or systemic circulation in several types of chronic liver diseases. Increased gut permeability and LPS play a role in alcoholic liver disease where alcohol impairs the gut epithelial integrity through alterations in tight junction proteins. In addition, non-alcoholic fatty liver disease is also associated with increased serum LPS levels and activation of the pro-inflammatory cascade plays a central role in disease progression. Microbial danger signals are recognized by pattern recognition receptors such as the Toll-like receptor 4 (TLR4). Increasing evidence suggests that TLR4-mediated signaling via the MyD88-dependent or MyD88-independent pathways may play different roles in liver diseases associated with increased LPS exposure of the liver as a result of gut permeability. For example, we showed that in alcoholic liver disease, the MyD88-independent, IRF3-dependent TLR4 cascade plays a role in steatosis and inflammation. Our recent data demonstrate that chronic alcohol exposure in the liver leads to sensitization of Kupffer cells to LPS via a mechanism involving upregulation of microRNA-155 in Kupffer cells. Thus, understanding the cell-specific recognition and intracellular signaling events in sensing gut-derived microbes will help to achieve an optimal balance in the gut-liver axis and ameliorate liver diseases. PMID:21525758

  8. Distortion definition and correction in off-axis systems

    Science.gov (United States)

    Da Deppo, Vania; Simioni, Emanuele; Naletto, Giampiero; Cremonese, Gabriele

    2015-09-01

    Off-axis optical configurations are becoming more and more used in a variety of applications, in particular they are the most preferred solution for cameras devoted to Solar System planets and small bodies (i.e. asteroids and comets) study. Off-axis designs, being devoid of central obstruction, are able to guarantee better PSF and MTF performance, and thus higher contrast imaging capabilities with respect to classical on-axis designs. In particular they are suitable for observing extended targets with intrinsic low contrast features, or scenes where a high dynamical signal range is present. Classical distortion theory is able to well describe the performance of the on-axis systems, but it has to be adapted for the off-axis case. A proper way to deal with off-axis distortion definition is thus needed together with dedicated techniques to accurately measure and hence remove the distortion effects present in the acquired images. In this paper, a review of the distortion definition for off-axis systems will be given. In particular the method adopted by the authors to deal with the distortion related issues (definition, measure, removal) in some off-axis instruments will be described in detail.

  9. Angular momentum projection of tilted axis rotating states

    Energy Technology Data Exchange (ETDEWEB)

    Oi, M.; Onishi, N.; Tajima, N. [Tokyo Univ. (Japan); Horibata, T.

    1998-03-01

    We applied an exact angular momentum projection to three dimensional cranked HFB (3d-CHFB) states. Tilted axis rotating states (TAR) and principal axis rotating states (PAR) are compared. It is shown that TAR is more adequate than PAR for description of the back bending phenomena driven by tilted rotation or wobbling motion. (author)

  10. A Method for Modeling of Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Wang, Kai; Hansen, Martin Otto Laver; Moan, Torgeir

    2013-01-01

    It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper...

  11. Spin-stabilized magnetic levitation without vertical axis of rotation

    Science.gov (United States)

    Romero, Louis; Christenson, Todd; Aaronson, Gene

    2009-06-09

    The symmetry properties of a magnetic levitation arrangement are exploited to produce spin-stabilized magnetic levitation without aligning the rotational axis of the rotor with the direction of the force of gravity. The rotation of the rotor stabilizes perturbations directed parallel to the rotational axis.

  12. Fracture modes in off-axis fiber composites

    Science.gov (United States)

    Sinclair, J. H.; Chamis, C. C.

    1979-01-01

    Criteria have been developed for identifying, characterizing, and quantifying fracture modes in high-modulus graphite-fiber/resin unidirectional composites subjected to off-axis tensile loading. Procedures are described which use sensitivity analyses and off-axis data to determine the uniaxial strength of fiber composites. It was found that off-axis composites fail by three fracture modes which produce unique fracture surface characteristics. The stress that dominates each fracture mode and the load angle range of its dominance can be identified. Linear composite mechanics is adequate to describe quantitatively the mechanical behavior of off-axis composites. The uniaxial strengths predicted from off-axis data are comparable to those measured in uniaxial tests.

  13. Computational studies of horizontal axis wind turbines

    Science.gov (United States)

    Xu, Guanpeng

    A numerical technique has been developed for efficiently simulating fully three-dimensional viscous fluid flow around horizontal axis wind turbines (HAWT) using a zonal approach. The flow field is viewed as a combination of viscous regions, inviscid regions and vortices. The method solves the costly unsteady Reynolds averaged Navier-Stokes (RANS) equations only in the viscous region around the turbine blades. It solves the full potential equation in the inviscid region where flow is irrotational and isentropic. The tip vortices are simulated using a Lagrangean approach, thus removing the need to accurately resolve them on a fine grid. The hybrid method is shown to provide good results with modest CPU resources. A full Navier-Stokes based methodology has also been developed for modeling wind turbines at high wind conditions where extensive stall may occur. An overset grid based version that can model rotor-tower interactions has been developed. Finally, a blade element theory based methodology has been developed for the purpose of developing improved tip loss models and stall delay models. The effects of turbulence are simulated using a zero equation eddy viscosity model, or a one equation Spalart-Allmaras model. Two transition models, one based on the Eppler's criterion, and the other based on Michel's criterion, have been developed and tested. The hybrid method has been extensively validated for axial wind conditions for three rotors---NREL Phase II, Phase III, and Phase VI configurations. A limited set of calculations has been done for rotors operating under yaw conditions. Preliminary simulations have also been carried out to assess the effects of the tower wake on the rotor. In most of these cases, satisfactory agreement has been obtained with measurements. Using the numerical results from present methodologies as a guide, Prandtl's tip loss model and Corrigan's stall delay model were correlated with present calculations. An improved tip loss model has been

  14. Notes on Mugger Crocodile Crocodylus palustris (Lesson, 1831) hunting on Axis axis in Bardia National Park, Nepal

    OpenAIRE

    Bhattarai, Santosh

    2016-01-01

    Mugger Crocodile Crocodylus palustris is a specialized voracious predator. Hunting strategy of the Mugger on the Axis axis deer and food storing for later use behavior of Crocodylus palustris is documented in Bardia National Park, Nepal. Understanding the diet of the Mugger is of great significance in Bardia National Park for its conservation and management.

  15. Kinematic and Dynamic Analyses of the Orthoglide 5-axis

    CERN Document Server

    Ur-Rehman, Raza; Chablat, Damien; Wenger, Philippe

    2008-01-01

    This paper deals with the kinematic and dynamic analyses of the Orthoglide 5-axis, a five-degree-of-freedom manipulator. It is derived from two manipulators: i) the Orthoglide 3-axis; a three dof translational manipulator and ii) the Agile eye; a parallel spherical wrist. First, the kinematic and dynamic models of the Orthoglide 5-axis are developed. The geometric and inertial parameters of the manipulator are determined by means of a CAD software. Then, the required motors performances are evaluated for some test trajectories. Finally, the motors are selected in the catalogue from the previous results.

  16. Design characteristics to reduce inadvertent cross-axis coupling during side stick handling of aircraft pitch and roll axis control

    Science.gov (United States)

    Cote, Marie-Eve

    Integrating a manual flight control inceptor with coupled axes such as the side stick within a flight deck creates challenges for the pilot to input a one-axis command without inadvertently inducing inputs in the opposite axis. The present paper studies three design features of the side stick and armrest setup believed to help reduce inadvertent cross-axis coupling occurrences. Design features address the aimed pilot population anthropometry (1.57m woman to 1.9m male) and their variability in upper segment measurements. Seven pilots of varying anthropometric sizes were asked to perform one-axis manoeuvres in pitch and roll for each setup configuration. To compare the setups both the duration and the definite integral of the unintended cross-axis input were processed and analyzed for each manoeuvre. Findings show that a short armrest reduces the occurrences of cross-axis input for the roll manoeuvre, whereas the side stick skew reduces inadvertent cross-axis coupling for the pitch manoeuvres.

  17. Circular Interpolation Algorithms of 5-Axis Simultaneous CNC System

    Institute of Scientific and Technical Information of China (English)

    ZHENG Kuijing; SHANG Bo

    2006-01-01

    Spatial circular arc can be machined conveniently by a 5-axis NC machine tool. Based on the data sampling method, circular interpolation in two-dimensional plane is discussed briefly. The key is to solve the problem of circular center expressed in the workpiece coordinate system by means of the transformation matrix. Circular interpolation in three-dimensional space is analyzed in detail. The method of undetermined coefficient is used to solve the center of the spatial circle and the method of coordinate transformation is used to transform the spatial circle into the XY_plane. Circular arc in three-dimensional space can be machined by the positional 5-axis machining and the conical surface can be machined by the continuous 5-axis machining. The velocity control is presented to avoid the feedrate fluctuation. The interpolation algorithms are tested by a simulation example and the interpolation algorithms are proved feasible. The algorithms are applied to the 5-axis CNC system software.

  18. Determination of Elastic Twist in Horizontal Axis Wind Turbines (HAWTs)

    Energy Technology Data Exchange (ETDEWEB)

    Stoddard, F.; Nelson, V.; Starcher, K.; Andrews, B.

    2006-06-01

    This report presents the results of a project at the Alternative Energy Institute (AEI) which measured and calculated the elastic twist of three representative composite horizontal-axis blades: Carter 300, Gougeon ESI 54, and UTRC 8 kW.

  19. Gonadal steroid hormones and the hypothalamo-pituitary-adrenal axis.

    Science.gov (United States)

    Handa, Robert J; Weiser, Michael J

    2014-04-01

    The hypothalamo-pituitary-adrenal (HPA) axis represents a complex neuroendocrine feedback loop controlling the secretion of adrenal glucocorticoid hormones. Central to its function is the paraventricular nucleus of the hypothalamus (PVN) where neurons expressing corticotropin releasing factor reside. These HPA motor neurons are a primary site of integration leading to graded endocrine responses to physical and psychological stressors. An important regulatory factor that must be considered, prior to generating an appropriate response is the animal's reproductive status. Thus, PVN neurons express androgen and estrogen receptors and receive input from sites that also express these receptors. Consequently, changes in reproduction and gonadal steroid levels modulate the stress response and this underlies sex differences in HPA axis function. This review examines the make up of the HPA axis and hypothalamo-pituitary-gonadal (HPG) axis and the interactions between the two that should be considered when exploring normal and pathological responses to environmental stressors. PMID:24246855

  20. The effects of lateral head tilt on ocular astigmatic axis

    Directory of Open Access Journals (Sweden)

    Hamid Fesharaki

    2014-01-01

    Conclusion: Any minimal angle of head tilt may cause erroneous measurement of astigmatic axis and should be avoided during refraction. One cannot rely on the compensatory function of ocular counter-torsion during the refraction.

  1. Off-axis vortex breakdown in a shallow whirlpool

    Science.gov (United States)

    Herrada, Miguel A.; Shtern, Vladimir N.; López-Herrera, José María

    2013-06-01

    The off-axis emergence of vortex breakdown (VB) is revealed. The steady axisymmetric flow in a vertical sealed cylinder, which is partially filled with water and the rest is filled with air, is driven by the rotating bottom disk. The numerical simulations show that VB can emerge away from the rotation axis, interface, and walls. As the rotation intensifies, VB first develops in the water region. If the water height is less (larger) than nearly one half of the cylinder radius, VB emerges off (on) the axis. As the rotation further increases, the off-axis VB ring touches the interface and then a thin countercirculation layer develops in the air flow above the water VB domain. This two-fluid VB ring shrinks (it even disappears in a very shallow whirlpool) as the interface approaches the bottom disk.

  2. Space/Flight Operable Miniature Six Axis Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — FUTEK will fully design and manufacture a sensor capable of measuring forces in and about each axis. The unit will measure forces up to 300 Newton's in the...

  3. Proper time axis of a closed relativistic system

    International Nuclear Information System (INIS)

    The definition of a proper time axis of a closed relativistic system of colliding particles is given. The solution of the proper time axis problem is presented. If the light velocity c equals the imaginary unit i, then in the case of a plane motion of the system the problem about the proper time axis turns out to be equivalent to the known in engineering mechanics problem about the reduction of any system of forces, applied to a rigid body, to the dynamic screw. In the general case, when c=i, the problem about the proper time axis turns out to be equivalent to the problem about the reduction to the dynamic screw of a system of forces, applied to a rigid body in a four-dimensional Euclidean space

  4. Bucket-by-bucket on-axis/off-axis injection by fast kicker with variable position dependence of kick

    International Nuclear Information System (INIS)

    The bucket-by-bucket on-axis/off-axis injection system is proposed with new stripline fast kicker with variable position dependence of kick, from dipole to quadrupole, controlled by the drive voltage and its polarity. Applying the injection system to on-axis injection necessary for ultimate storage rings with narrow dynamic aperture, every bucket can be stored to achieve high average current with top-up operation. Also the minimum perturbation for stored beam can be achieved with the system by limiting the perturbations to injected bucket. Also the impurity electrons are prevented from injection with this system. (author)

  5. Vertical Axis Wind Turbines : Electrical System and Experimental Results

    OpenAIRE

    Kjellin, Jon

    2012-01-01

    The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. The experimental work presented in this thesis comprises investigation of three vertical axis wind turbines of different design and size. The electrical, control and measurement systems for the first 12 kW wind turbine have...

  6. Dynamic Compensation for Two-Axis Robot Wrist Force Sensors

    OpenAIRE

    Junqing Ma; Aiguo Song; Dongcheng Pan

    2013-01-01

    To improve the dynamic characteristic of two-axis force sensors, a dynamic compensation method is proposed. The two-axis force sensor system is assumed to be a first-order system. The operation frequency of the system is expanded by a digital filter with backward difference network. To filter high-frequency noises, a low-pass filter is added after the dynamic compensation network. To avoid overcompensation, parameters of the proposed dynamic compensation method are defined by trial and error....

  7. MAP: Medial axis based geometric routing in sensor networks

    OpenAIRE

    Bruck, Jehoshua; Gao, Jie; Jiang, Anxiao

    2007-01-01

    One of the challenging tasks in the deployment of dense wireless networks (like sensor networks) is in devising a routing scheme for node to node communication. Important consideration includes scalability, routing complexity, quality of communication paths and the load sharing of the routes. In this paper, we show that a compact and expressive abstraction of network connectivity by the medial axis enables efficient and localized routing. We propose MAP, a Medial Axis based naming and routing...

  8. The reno-pineal axis: A novel role for melatonin

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2012-01-01

    Full Text Available The pineal gland is a tiny endocrine gland whose physiologic role has been the focus of much research and much more speculation over the past century. This mini-review discusses recent findings which correlate melatonin and renal physiology, and postulates the presence of a "reno-pineal axis." Drawing lessons from comparative endocrinology, while quoting human data, it advocates the need to study the "reno-pineal axis" in greater detail.

  9. The Post Processing Developing of Five-axis CNC Machine

    OpenAIRE

    Anjiang Cai; Bin Li; Shihong Guo; Zhaoyang Dong

    2012-01-01

    In this study, we have a research of the methods of the special post processing program developing of Five-axis CNC machine DMC 70ev. On the basis of analysis about the characteristics of MILLPLUS IT V530 CNumerical control system, special post processor applied to five-axis CNC machining mode based on IMSPost was developed. Special post processing program developed was proved its accuracy and reliability by put it into practice. The research results has important significance for post proces...

  10. Axis I diagnostic comorbidity and borderline personality disorder.

    Science.gov (United States)

    Zimmerman, M; Mattia, J I

    1999-01-01

    Borderline personality disorder (PD) has been the most studied PD. Research has examined the relationship between borderline PD and most axis I diagnostic classes such as eating disorders, mood disorders, and substance use disorders. However, there is little information regarding the relationship of borderline PD and overall comorbidity with all classes of axis I disorders assessed simultaneously. In the present study, 409 patients were evaluated with semistructured diagnostic interviews for axis I and axis II disorders. Patients with a diagnosis of borderline PD versus those who did not receive the diagnosis were assigned significantly more current axis I diagnoses (3.4 v 2.0). Borderline PD patients were twice as likely to receive a diagnosis of three or more current axis I disorders (69.5% v 31.1%) and nearly four times as likely to have a diagnosis of four or more disorders 147.5% v 13.7%). In comparison to nonborderline PD patients, borderline PD patients more frequently received a diagnosis of current major depressive disorder (MDD), bipolar I and II disorder, panic disorder with agoraphobia, social and specific phobia, posttraumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), eating disorder NOS, and any somatoform disorder. Similar results were observed for lifetime diagnoses. Overall, borderline PD patients were more likely to have multiple axis I disorders than nonborderline PD patients, and the differences between the two groups were present across mood, anxiety, substance use, eating, and somatoform disorder categories. These findings highlight the importance of performing thorough evaluations of axis I pathology in patients with borderline PD in order not to overlook syndromes that are potentially treatment-responsive. PMID:10428182

  11. Application of circulation controlled blades for vertical axis wind turbines

    OpenAIRE

    Velissarios Kourkoulis; Andrew Shires

    2013-01-01

    The blades of a vertical axis wind turbine (VAWT) rotor see an inconsistent angle of attack through its rotation. Consequently, VAWT blades generally use symmetrical aerofoils with a lower lift-to-drag ratio than cambered aerofoils tailored to maximise horizontal axis wind turbine rotor performance. This paper considers the feasibility of circulation controlled (CC) VAWT blades, using a tangential air jet to provide lift and therefore power augmentation. However CC blade sections require a hi...

  12. Rotation axis demultiplexer enabling simultaneous computed tomography of multiple samples

    OpenAIRE

    Trtik, Pavel; Geiger, Fabian; Hovind, Jan; Lang, Udo; Lehmann, Eberhard; Vontobel, Peter; Peetermans, Steven

    2016-01-01

    This paper describes a device that allows for simultaneous tomographic imaging of samples on three independent rotational axes. This rotation axis demultiplexer (POLYTOM) is equipped with anti-backlash gears and placed on a standard sample rotation stage thus allowing for the transformation of the input rotation axis onto two additional parallel vertical axes. Consequently, three times the number of samples can be investigated within a given time period, thereby reducing the acquisition time ...

  13. Vertical Axis Wind Turbines : Tower Dynamics and Noise

    OpenAIRE

    Möllerström, Erik

    2015-01-01

    Vertical axis wind turbines (VAWTs) have with time been outrivaled by the today common and economically feasible horizontal axis wind turbines (HAWTs). However, VAWTs have several advantages such as the possibility to put the drive train at ground level, lower noise emissions and better scaling behavior which still make them interesting for research. The work within this thesis is made in collaboration between the Department of Construction and Energy Engineering at Halmstad University and th...

  14. Small Vertical Axis Wind Turbines: aerodynamics and starting behavior

    OpenAIRE

    Dumitrescu, Horia; Vladimir CARDOS; Radu BOGATEANU

    2013-01-01

    In urban areas the wind is very turbulent and unstable with fast changes in direction andvelocity. In these environments, the use of small vertical axis wind turbines (VAWT) becomesincreasingly attractive due to several advantages over horizontal axis wind turbines (HAWT).However, such designs have received much less attention than the more common propeller-typedesigns and the understanding of same aspects of their operation remains, to this day, incomplete.This is particularly true of their ...

  15. Experimental study of the subtalar joint axis: preliminary investigation.

    Science.gov (United States)

    Zographos, S; Chaminade, B; Hobatho, M C; Utheza, G

    2000-01-01

    An experimental study of the subtalar joint has been conducted with the aim of establishing its axis of movement as well as analysing the associated movement. For description of the axis, CT data for five positions of a single foot were reconstructed using a 3D programme, the 3D data was processed by Patran software. Measures of angular displacements were made from three amputated feet placed in a specially constructed foot frame. Four instantaneous axes of movement could be defined. Calculation of displacements showed an important rolling of the calcaneus (45 degrees). Tacking was evident in inversion, with an opposite displacement between the front and rear part of the calcaneus, whereas during eversion tacking affected only the rear part of the bone: these results were confirmed by 3D reconstructions. Henke's axis was described as that for the talonavicular joint, but acceptable for the subtalar joint. Several authors investigating the coordinates of this axis have reported large differences and described screw-like movements, the latter being incompatible with a fixed axis: instantaneous axes, however are compatible with a screw-like movement. The subtalar joint appears to work as a pivot joint during inversion and as a plane joint during eversion. Although Henke's axis has pedagogical value the subtalar joint has a series of instantaneous axes. PMID:11236321

  16. Major and minor axis kinematics of 22 ellipticals

    Science.gov (United States)

    Franx, Marijn; Illingworth, Garth; Heckman, Timothy

    1989-09-01

    Rotation curves and velocity dispersion profiles have been determined for the major and the minor axes of 22 elliptical galaxies. Rotation was detected in all but one galaxy, even though the sample was biased toward round ellipticals. Minor axis rotation larger than major axis rotation was measured in two galaxies, NGC 4406 and NGC 7507. Roughly 10 percent of ellipticals may show large minor axis velocities relative to those on the major axis. A simple model is used to derive a rotational axis from the observed minor and major axis velocities to a typical accuracy of 6 deg. The rotational and photometric minor axes aligned to better than 10 deg for 60 percent of the sample, implying that the direction of the angular momentum is related to the orientation of the figure of the galaxy. IC 1459 has a kinematically distinct core with its angular momentum opposite to the angular momentum of the outer parts, and NGC 4406 has a core with its angular momentum perpendicular to that of the outer parts.

  17. Celiac axis stenosis and lethal liver ischemia after pancreaticoduodenectomy.

    Science.gov (United States)

    Lipska, Ludmila; Visokai, Vladimir; Levy, Miroslav; Koznar, Boris; Zaruba, Pavel

    2009-01-01

    Celiac axis stenosis can lead to a fatal hepatic ischemia after pancreaticoduodenectomy unless a simultaneous revascularisation of the celiac circulation is performed. In the present study are reported three cases of celiac axis stenosis, all of which had histologically confirmed periampullary cancer. Case 1: a 50-year-old male with a history of myocardial infarction and liver steatosis; visceral arteriography prior to the surgery demonstrated a celiac axis stenosis. Whipple operation was performed. After removing the specimen, no signs of liver ischemia were found (liver was cholestatic) and pulsation of the hepatic artery was strong. The patient died on the second postoperative day after an abrupt irreversible cardiac arrest. Autopsy proved acute severe hepatic ischemia. Case 2: a 64-year-old female. Preoperative visceral angiography showed significant celiac axis stenosis. As a first step of surgery the root of the celiac trunk was exposed, a fibrotic ring around it was divided. Standard D1 pylorus preserving pancreaticoduodenectomy was performed. Case 3: a 58-year-old female without preoperative angiography, indicated for surgery. After an occlusion test of the gastroduodenal artery the liver became ischemic. Division of the fibrotic ring around celiac axis was performed together with a standard D1 pylorus preserving pancreaticoduodenectomy. No postoperative complications were reported in both case 2 and 3. PMID:19760970

  18. Off-axis angular spectrum method with variable sampling interval

    Science.gov (United States)

    Kim, Yong-Hae; Byun, Chun-Won; Oh, Himchan; Pi, Jae-Eun; Choi, Ji-Hun; Kim, Gi Heon; Lee, Myung-Lae; Ryu, Hojun; Hwang, Chi-Sun

    2015-08-01

    We proposed a novel off-axis angular spectrum method (ASM) for simulating free space wave propagation with a large shifted destination plane. The off-axis numerical simulation took wave propagation between a parallel source and a destination plane, but a destination plane was shifted from a source plane. The shifted angular spectrum method was proposed for diffraction simulation with a shifted destination plane and satisfied the Nyquist condition for sampling by limiting a bandwidth of a propagation field to avoid an aliasing error due to under sampling. However, the effective sampling number of the shifted ASM decreased when the shifted distance of the destination plane was large which caused a numerical error in the diffraction simulation. To compensate for the decrease of an effective sampling number for the large shifted destination plane, we used a variable sampling interval in a Fourier space to maintain the same effective sampling number independent of the shifted distance of the destination plane. As a result, our proposed off-axis ASM with a variable sampling interval can produce simulation results with high accuracy for nearly every shifted distance of a destination plane when an off-axis angle is less than 75°. We compared the performances of the off-axis ASM using the Chirp Z transform and non-uniform FFT for implementing a variable spatial frequency in a Fourier space.

  19. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension

    Science.gov (United States)

    Anderson, Matthew J.; Schimmang, Thomas; Lewandoski, Mark

    2016-01-01

    During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM). Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3-BMP signaling axis is

  20. An FGF3-BMP Signaling Axis Regulates Caudal Neural Tube Closure, Neural Crest Specification and Anterior-Posterior Axis Extension.

    Directory of Open Access Journals (Sweden)

    Matthew J Anderson

    2016-05-01

    Full Text Available During vertebrate axis extension, adjacent tissue layers undergo profound morphological changes: within the neuroepithelium, neural tube closure and neural crest formation are occurring, while within the paraxial mesoderm somites are segmenting from the presomitic mesoderm (PSM. Little is known about the signals between these tissues that regulate their coordinated morphogenesis. Here, we analyze the posterior axis truncation of mouse Fgf3 null homozygotes and demonstrate that the earliest role of PSM-derived FGF3 is to regulate BMP signals in the adjacent neuroepithelium. FGF3 loss causes elevated BMP signals leading to increased neuroepithelium proliferation, delay in neural tube closure and premature neural crest specification. We demonstrate that elevated BMP4 depletes PSM progenitors in vitro, phenocopying the Fgf3 mutant, suggesting that excessive BMP signals cause the Fgf3 axis defect. To test this in vivo we increased BMP signaling in Fgf3 mutants by removing one copy of Noggin, which encodes a BMP antagonist. In such mutants, all parameters of the Fgf3 phenotype were exacerbated: neural tube closure delay, premature neural crest specification, and premature axis termination. Conversely, genetically decreasing BMP signaling in Fgf3 mutants, via loss of BMP receptor activity, alleviates morphological defects. Aberrant apoptosis is observed in the Fgf3 mutant tailbud. However, we demonstrate that cell death does not cause the Fgf3 phenotype: blocking apoptosis via deletion of pro-apoptotic genes surprisingly increases all Fgf3 defects including causing spina bifida. We demonstrate that this counterintuitive consequence of blocking apoptosis is caused by the increased survival of BMP-producing cells in the neuroepithelium. Thus, we show that FGF3 in the caudal vertebrate embryo regulates BMP signaling in the neuroepithelium, which in turn regulates neural tube closure, neural crest specification and axis termination. Uncovering this FGF3

  1. 艾灸对血管性痴呆大鼠海马内VEGF、flt-1、bFGF及bFGF-r表达的影响%Effects of Moxibustion on the Expressions of Hlppocampal VEGF, fit-1, bFGF, and bFGF-r in Vascular

    Institute of Scientific and Technical Information of China (English)

    王频; 汤敬一; 杨骏; 张庆萍

    2012-01-01

    Objective To observe the expression levels of hippocampal vascular endothelial growth factor (VEGF), fms-like tyrosine kinase-1 (flt-1), basic fibroblast growth factor (bFGF), and basic fibroblast growth factor receptor (bFGF-r) in vascular dementia (VD) rats, thus studying the angiogenesis mechanism of moxi-bustion in VD. Methods Sixty male elderly Wistar rats were selected. The VD rat model was prepared by bilateral carotid artery occlusion and reperfusion of sodium nitroprusside injection. The model rats were divided into 3 groups by the random digit table, I. E., the moxibustion group, the Western medicine group, and the model group. A sham-operation control group was also set up. In the moxibustion group rats was acupunctured at Baihui (GV20), Shenting (GV14), and Dazhui (GV24). Aniracetam was given to rats in the Western medicine group by gastrogavage for 2 therapeutic courses, 15 days as one course. The learning and memory results were observed by the neuroethological score in combination of step-down avoidance test before treatment and by the end of the 2nd course respectively. The expression levels of hippocampal VEGF, flt-1, bFGF, and bFGF-r of allrats were detected using immunohistochemical assay. Results After 2 courses of treatment, statistical difference existed in the latent period, the error times, and the neuroethological score in the moxibustion group and the Western medicine group when compared with the model group (P<0.01, P<0. 05). Statistical difference existed in the latent period and the neuroethological score between the moxibustion group and the Western medicine group (P<0. 05), which indicated that moxibustion and Western medicine showed significant effects in improving the latent period, decreasing the error times and the neuroethological score. Better results were obtained in the moxibustion group than in the Western medicine group (P<0. 01, P<0. 05). Statistical difference of the average grey level (AGL) of hippocampal VEGF, flt-1, and

  2. Emergence of principal axis rotation in 110Ag

    International Nuclear Information System (INIS)

    The negative-parity yrast band of 110Ag has been extended significantly and the lifetimes of the high spin levels of this band have been measured. The experimentally observed level scheme and measured electromagnetic transition rates have been compared with the theoretical predictions of a model with two quasiparticles coupled to a triaxially deformed core. This calculation successfully reproduces the energy spectra and electromagnetic transition rates beyond Iπ=12-ℏ. These observations indicate that the principal axis of rotation is responsible for the generation of high angular momentum states along the yrast cascade in 110Ag. In all the other lighter isotopes, these states are generated through titled axis rotation. Thus, 110Ag is the first nucleus where the boundary between tilted and principal axis rotation could be established.

  3. Central configurations of four bodies with an axis of symmetry

    Science.gov (United States)

    Érdi, Bálint; Czirják, Zalán

    2016-05-01

    A complete solution is given for a symmetric case of the problem of the planar central configurations of four bodies, when two bodies are on an axis of symmetry, and the other two bodies have equal masses and are situated symmetrically with respect to the axis of symmetry. The positions of the bodies on the axis of symmetry are described by angle coordinates with respect to the outside bodies. The solution is such, that giving the angle coordinates, the masses for which the given configuration is a central configuration, can be computed from simple analytical expressions of the angles. The central configurations can be described as one-parameter families, and these are discussed in detail in one convex and two concave cases. The derived formulae represent exact analytical solutions of the four-body problem.

  4. Role of Met Axis in Head and Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Yiru, E-mail: xuyiru@umich.edu; Fisher, Gary J., E-mail: xuyiru@umich.edu [Department of Dermatology, University of Michigan, Ann Arbor, MI 48109 (United States)

    2013-11-26

    Head and neck cancer is the sixth most common type of cancer worldwide. Despite advances in aggressive multidisciplinary treatments, the 5-year survival rate for this dreadful disease is only 50%, mostly due to high rate of recurrence and early involvement of regional lymph nodes and subsequent metastasis. Understanding the molecular mechanisms responsible for invasion and metastasis is one of the most pressing goals in the field of head and neck cancer. Met, also known as hepatocyte growth factor receptor (HGFR), is a member of the receptor protein tyrosine kinase (RPTK) family. There is compelling evidence that Met axis is dysregulated and plays important roles in tumorigenesis, progression, metastasis, angiogenesis, and drug resistance in head and neck cancer. We describe in this review current understanding of Met axis in head and neck cancer biology and development of therapeutic inhibitors targeting Met axis.

  5. Microwave Bragg-scattering zone-axis-pattern analysis

    CERN Document Server

    Fraundorf, P; Garver, W; Freeman, M; Proctor, D

    2013-01-01

    Louis deBroglie's connection between momentum and spatial-frequency vectors is perhaps most viscerally-experienced via the real-time access that electron-diffraction provides to transverse slices of a crystal's reciprocal lattice. The classic introductory (and/or advanced) physics lab-experiment on microwave Bragg-scattering can with a bit of re-arrangement also give students access to "zone-axis-pattern" slices through the 3D spatial-frequency (i.e. reciprocal) lattice of a ball-bearing crystal. In this paper we show how data from the standard experimental set up can be used to generate zone-axis-patterns oriented down the crystal rotation-axis. This may be used to give students direct experience with crystal shape-transforms (which help to explain anomalous peaks), as well as to the complementary relation between non-Cartesian basis-vectors in direct and reciprocal (co-vector) space.

  6. The Minimal Model of the Hypothalamic-Pituitary-Adrenal Axis

    DEFF Research Database (Denmark)

    Vinther, Frank; Andersen, Morten; Ottesen, Johnny T.

    2011-01-01

    This paper concerns ODE modeling of the hypothalamic-pituitary-adrenalaxis (HPA axis) using an analytical and numerical approach, combined with biological knowledge regarding physiological mechanisms and parameters. The three hormones, CRH, ACTH, and cortisol, which interact in the HPA axis are...... modeled as a system of three coupled, nonlinear differential equations. Experimental data shows the circadian as well as the ultradian rhythm. This paper focuses on the ultradian rhythm. The ultradian rhythm can mathematically be explained by oscillating solutions. Oscillating solutions to an ODE emerges...... from an unstable fixed point with complex eigenvalues with a positive real parts and a non-zero imaginary parts. The first part of the paper describes the general considerations to be obeyed for a mathematical model of the HPA axis. In this paper we only include the most widely accepted mechanisms that...

  7. Small Vertical Axis Wind Turbines: aerodynamics and starting behavior

    Directory of Open Access Journals (Sweden)

    Horia DUMITRESCU

    2013-12-01

    Full Text Available In urban areas the wind is very turbulent and unstable with fast changes in direction andvelocity. In these environments, the use of small vertical axis wind turbines (VAWT becomesincreasingly attractive due to several advantages over horizontal axis wind turbines (HAWT.However, such designs have received much less attention than the more common propeller-typedesigns and the understanding of same aspects of their operation remains, to this day, incomplete.This is particularly true of their starting characteristics. Indeed, same authors heuristically maintainthat they cannot start without external assistance. This paper reviews the cause of the inability of thelow solidity fixed pitch vertical axis wind turbines to self-start, and investigates the way ofovercoming this draw back.

  8. Axis Patterning by BMPs: Cnidarian Network Reveals Evolutionary Constraints

    Directory of Open Access Journals (Sweden)

    Grigory Genikhovich

    2015-03-01

    Full Text Available BMP signaling plays a crucial role in the establishment of the dorso-ventral body axis in bilaterally symmetric animals. However, the topologies of the bone morphogenetic protein (BMP signaling networks vary drastically in different animal groups, raising questions about the evolutionary constraints and evolvability of BMP signaling systems. Using loss-of-function analysis and mathematical modeling, we show that two signaling centers expressing different BMPs and BMP antagonists maintain the secondary axis of the sea anemone Nematostella. We demonstrate that BMP signaling is required for asymmetric Hox gene expression and mesentery formation. Computational analysis reveals that network parameters related to BMP4 and Chordin are constrained both in Nematostella and Xenopus, while those describing the BMP signaling modulators can vary significantly. Notably, only chordin, but not bmp4 expression needs to be spatially restricted for robust signaling gradient formation. Our data provide an explanation of the evolvability of BMP signaling systems in axis formation throughout Eumetazoa.

  9. Observation of equilibria with a double magnetic axis in LHD

    International Nuclear Information System (INIS)

    Plasma shape control is a major knob to investigate confinement as well as MHD characteristics of magnetically confined plasmas. LHD has a large flexibility to explore a configuration effect by using 6 independent coil systems. Elongation can be controlled by a quadrupole field. Experimental observation of moderate elongation has shown that confinement is degraded gradually in both prolate (vertically elongated) and oblate (horizontally elongated) configurations. Since the rotational transform is weaker in the core region than in the periphery in LHD, a theoretical analysis suggests that excess quadrupole field results in split of the magnetic axis. Then the internal separatrix like petals emerges. Further application of quadrupole field eventually realizes a doublet configuration with a double magnetic axis bounded by this separatrix. An analytics suggests that split of the magnetic axis starts beyond elongation κ of 1.6 in the prolate case. The role of separatrix is attracting interest in effect on confinement performance as well as physics of unstable manifold, which has motivated strong shaping experiment in LHD. Both shaping of prolate and oblate directions has been explored for NBI heated plasmas. In the strongly prolate case, the doublet image has been observed by a tangential soft X-ray camera. Available profile measurements of temperature and density have not provided the 2-dimensional profile, however, assumption of concentric surfaces with a single magnetic axis seems to contradict with experimental observations in the 1-dimensional measurements in the case with strong shaping. This suggests the existence of doublet magnetic surfaces. These complex equilibria cannot be treated by the numerical code, ex. VMEC, with an assumption of nested flux surfaces with a single magnetic axis. Characteristics of these eccentric equilibria have been investigated by the HINT code which does not assume existence of nested flux surfaces. Experimental and computational

  10. Calibration of three-axis magnetometers with differential evolution algorithm

    International Nuclear Information System (INIS)

    The accuracy of three-axis magnetometers is influenced by different scale and bias of each axis and nonorthogonality between axes. One limitation of traditional iteration methods is that initial parameters influence the calibration, thus leading to the local optimal or wrong results. In this paper, a new method is proposed to calibrate three-axis magnetometers. To employ this method, a nonmagnetic rotation platform, a proton magnetometer, a DM-050 three-axis magnetometer and the differential evolution (DE) algorithm are used. The performance of this calibration method is analyzed with simulation and experiment. In simulation, the calibration results of DE, unscented Kalman filter (UKF), recursive least squares (RLS) and genetic algorithm (GA) are compared. RMS error using DE is least, which is reduced from 81.233 nT to 1.567 nT. Experimental results show that comparing with UKF, RLS and GA, the DE algorithm has not only the least calibration error but also the best robustness. After calibration, RMS error is reduced from 68.914 nT to 2.919 nT. In addition, the DE algorithm is not sensitive to initial parameters, which is an important advantage compared with traditional iteration algorithms. The proposed algorithm can avoid the troublesome procedure to select suitable initial parameters, thus it can improve the calibration performance of three-axis magnetometers. - Highlights: • The calibration results and robustness of UKF, GA, RLS and DE algorithm are analyzed. Calibration error of DE is the least in simulation and experiment. • Comparing with traditional calibration algorithms, DE is not sensitive to initial parameters. • It can improve the calibration performance of three-axis magnetometers

  11. Spin-axis pointing of a magnetically actuated spacecraft

    Science.gov (United States)

    Avanzini, G.; de Angelis, E. L.; Giulietti, F.

    2014-01-01

    Attitude regulation proves to be a challenging problem, when magnetic actuators alone are used as attitude effectors, since they do not provide three independent control torque components at each time instant. In this paper a rigorous proof of global exponential stability is derived for a magnetic control law that leads the satellite to a desired spin condition around a principal axis of inertia, pointing the spin axis toward a prescribed direction in the inertial frame. The technique is demonstrated by means of numerical simulation of a few example maneuvers. An extensive Monte Carlo simulation is performed for random initial conditions, in order to investigate the effect of changes in control law gains.

  12. Efficient Path Query and Reasoning Method Based on Rare Axis

    Institute of Scientific and Technical Information of China (English)

    姜洋; 冯志勇; 王鑫马晓宁

    2015-01-01

    A new concept of rare axis based on statistical facts is proposed, and an evaluation algorithm is designed thereafter. For the nested regular expressions containing rare axes, the proposed algorithm can reduce its evaluation complexity from polynomial time to nearly linear time. The distributed technique is also employed to construct the navigation axis indexes for resource description framework (RDF) graph data. Experiment results in DrugBank and BioGRID show that this method can improve the query efficiency significantly while ensuring the accuracy and meet the query requirements on Web-scale RDF graph data.

  13. Fluctuation of electromagnetic cascade axis in dense amorphous segmented media

    International Nuclear Information System (INIS)

    The investigation of fluctuation of the so-called energy cascade axis around the geometry cascade axis for electromagnetic cascade produced in liquid xenon by gamma quanta within the energy interval 100-3500 MeV has been performed. As a basis the previously obtained experimental data from the 180- liter Xenon Bubble Chamber of ITEP were use. Our results may be helpful for the construction and further to improve the characteristics of electromagnetic calorimeters with fine-segmented active absorbers such as PANDA (GSI, Darmstardt) and SPHERE (LHE, JINR, Dubna)

  14. Three axis vector atomic magnetometer utilizing polarimetric technique

    CERN Document Server

    Pradhan, Swarupananda

    2016-01-01

    The three axis magnetic field measurement based on the interaction of a single elliptically polarized light beam with an atomic system is described. The magnetic field direction dependent atomic responses are extracted by the polarimetric detection in combination with laser frequency modulation and magnetic field modulation techniques. The magnetometer offers additional critical requirements like compact size and large dynamic range for space application. Further, the three axis magnetic field is measured using only reflected signal from the polarimeter, thus can be easily expanded to make spatial array of detectors or / and high sensitivity field gradient measurement as required for biomedical application.

  15. HIGH-SPEED 5-AXIS MACHINING FOR TOOLING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Saxer, M.

    2012-11-01

    Full Text Available In the modern metalworking industry, production moulds often have complex geometry, with undercut regions, small corner radii, sharp edges, deep cavities, or large cores. Conventional manufacturing process chains to machine these complex features are often lengthy and inefficient due to multiple steps. This article presents current results obtained through industry projects and experimental work using 5-axis high-speed machining with high-end CAD/CAM systems to improve process efficiency. Cost optimisation and lead time shortening can be clearly shown. This is of particular importance for South African manufacturing companies, where multi-axis HSC technology although not totally unknown is significantly under-used.

  16. Single Vector Calibration System for Multi-Axis Load Cells and Method for Calibrating a Multi-Axis Load Cell

    Science.gov (United States)

    Parker, Peter A. (Inventor)

    2003-01-01

    A single vector calibration system is provided which facilitates the calibration of multi-axis load cells, including wind tunnel force balances. The single vector system provides the capability to calibrate a multi-axis load cell using a single directional load, for example loading solely in the gravitational direction. The system manipulates the load cell in three-dimensional space, while keeping the uni-directional calibration load aligned. The use of a single vector calibration load reduces the set-up time for the multi-axis load combinations needed to generate a complete calibration mathematical model. The system also reduces load application inaccuracies caused by the conventional requirement to generate multiple force vectors. The simplicity of the system reduces calibration time and cost, while simultaneously increasing calibration accuracy.

  17. An improved computer controlled triple-axis neutron spectrometer

    International Nuclear Information System (INIS)

    A description is given of the computer-controlled triple-axis neutron spectrometer installed at the PLUTO reactor at Harwell. The reasons for an nature of recent major improvements are discussed. Following a general description of the spectrometer, details are then given of the new computerised control system, including the functions of the various programs which are now available to the user. (author)

  18. Brain-gut-microbiota axis in Parkinson's disease.

    Science.gov (United States)

    Mulak, Agata; Bonaz, Bruno

    2015-10-01

    Parkinson's disease (PD) is characterized by alpha-synucleinopathy that affects all levels of the brain-gut axis including the central, autonomic, and enteric nervous systems. Recently, it has been recognized that the brain-gut axis interactions are significantly modulated by the gut microbiota via immunological, neuroendocrine, and direct neural mechanisms. Dysregulation of the brain-gut-microbiota axis in PD may be associated with gastrointestinal manifestations frequently preceding motor symptoms, as well as with the pathogenesis of PD itself, supporting the hypothesis that the pathological process is spread from the gut to the brain. Excessive stimulation of the innate immune system resulting from gut dysbiosis and/or small intestinal bacterial overgrowth and increased intestinal permeability may induce systemic inflammation, while activation of enteric neurons and enteric glial cells may contribute to the initiation of alpha-synuclein misfolding. Additionally, the adaptive immune system may be disturbed by bacterial proteins cross-reacting with human antigens. A better understanding of the brain-gut-microbiota axis interactions should bring a new insight in the pathophysiology of PD and permit an earlier diagnosis with a focus on peripheral biomarkers within the enteric nervous system. Novel therapeutic options aimed at modifying the gut microbiota composition and enhancing the intestinal epithelial barrier integrity in PD patients could influence the initial step of the following cascade of neurodegeneration in PD. PMID:26457021

  19. Cellulose and the twofold screw axis: Modeling and experimental arguments

    Science.gov (United States)

    Crystallography indicates that molecules in crystalline cellulose either have 2-fold screw-axis (21) symmetry or closely approximate it, leading to short distances between H4 and H1' across the glycosidic linkage. Therefore, modeling studies of cellobiose often show elevated energies for 21 structur...

  20. Contribution to the method for determining femoral neck axis

    Directory of Open Access Journals (Sweden)

    Anđelković Zoran

    2014-01-01

    Full Text Available Introduction. Femoral neck axis plotting is of great significance in measuring parameters that define femoral head-neck junction sphericity in the group of patients with the femoroacetabular impingement. Literature methods of femoral neck axis determination have weaknesses associated with the risk of obtaining inaccurate values of certain parameters. Objective. Method of plotting of the femoral neck axis by two parallel lines that belong to the medial quarter of the femoral neck is proposed. Method was tested on the anatomic specimens and the respective radiograms. Methods. A total of 31 anatomic specimens of the proximal femur and respective radiographs were used, on which three axes of the femoral neck were plotted; accordingly, alpha angle value was determined and tested with corresponding parametric tests, with the measurement error of less than 5% and the strength of the applied tests of 80%. Results. Alpha angle values obtained by plotting femoral neck axis using the literature and methods we have proposed were not significantly different in our series, and, in more than a half of the specimens, the two axes overlapped each other. Conclusion. The advantage of the proposed method does not depend on the position of the femoral head rotation center in relation to the femoral neck, which favors proposed method for measuring the angles of femoral head sphericity in patients with the femoral head translation. Disadvantage of the study is a small sample size for valid conclusions about the applicability of this method in clinical practice.

  1. Survey of Unsteady Computational Aerodynamics for Horizontal Axis Wind Turbines

    Science.gov (United States)

    Frunzulicǎ, F.; Dumitrescu, H.; Cardoş, V.

    2010-09-01

    We present a short review of aerodynamic computational models for horizontal axis wind turbines (HAWT). Models presented have a various level of complexity to calculate aerodynamic loads on rotor of HAWT, starting with the simplest blade element momentum (BEM) and ending with the complex model of Navier-Stokes equations. Also, we present some computational aspects of these models.

  2. Stereo PIV Experiments on Horizontal Axis Wind Turbine Rotor Model

    NARCIS (Netherlands)

    Akay, B.; Micallef, D.; Ferreira, C.S.; Van Bussel, G.J.W.

    2011-01-01

    This paper sets out to describe the measurements and computations to construct three components of velocity field around the blade. The primary aim of the measurements was to gain insight into the physics of the flow field produced by a horizontal axis wind turbine-HAWT blade. Stereo Particle Image

  3. On the Turbulent Mixing in Horizontal Axis Wind Turbine Wakes

    NARCIS (Netherlands)

    Lignarolo, L.E.M.

    2016-01-01

    The wake flow of a horizontal axis wind turbine is characterised by lower wind speed and higher turbulence than the free-stream conditions. When clustered in large wind farms, wind turbines regularly operate inside the wake of one or more upstream machines. This is a major cause of energy production

  4. Spin fluids in stationary axis-symmetric space-times

    International Nuclear Information System (INIS)

    The relations establishing the equivalence of an ordinary perfect fluid stress-energy tensor and a spin fluid stress-energy tensor are derived for stationary axis-symmetric space-times in general relativity. Spin fluid sources for the Goedel cosmology and the van Stockum metric are given

  5. Spin fluids in stationary axis-symmetric space-times

    Science.gov (United States)

    Krisch, J. P.

    1987-07-01

    The relations establishing the equivalence of an ordinary perfect fluid stress-energy tensor and a spin fluid stress-energy tensor are derived for stationary axis-symmetric space-times in general relativity. Spin fluid sources for the Gödel cosmology and the van Stockum metric are given.

  6. Tilted axis rotation in odd-odd {sup 164}Tm

    Energy Technology Data Exchange (ETDEWEB)

    Reviol, W.; Riedinger, L.L.; Wang, X.Z.; Zhang, J.Y. [Univ. of Tennessee, Knoxville, TN (United States)] [and others

    1996-12-31

    Ten band structures are observed in {sup 164}Tm, among them sets of parallel and anti-parallel couplings of the proton and neutron spins. The Tilted Axis Cranking scheme is applied for the first time to an odd-odd nucleus in a prominent region of nuclear deformation.

  7. Analytical Aerodynamic Simulation Tools for Vertical Axis Wind Turbines

    International Nuclear Information System (INIS)

    Wind power is a renewable energy source that is today the fastest growing solution to reduce CO2 emissions in the electric energy mix. Upwind horizontal axis wind turbine with three blades has been the preferred technical choice for more than two decades. This horizontal axis concept is today widely leading the market. The current PhD thesis will cover an alternative type of wind turbine with straight blades and rotating along the vertical axis. A brief overview of the main differences between the horizontal and vertical axis concept has been made. However the main focus of this thesis is the aerodynamics of the wind turbine blades. Making aerodynamically efficient turbines starts with efficient blades. Making efficient blades requires a good understanding of the physical phenomena and effective simulations tools to model them. The specific aerodynamics for straight bladed vertical axis turbine flow are reviewed together with the standard aerodynamic simulations tools that have been used in the past by blade and rotor designer. A reasonably fast (regarding computer power) and accurate (regarding comparison with experimental results) simulation method was still lacking in the field prior to the current work. This thesis aims at designing such a method. Analytical methods can be used to model complex flow if the geometry is simple. Therefore, a conformal mapping method is derived to transform any set of section into a set of standard circles. Then analytical procedures are generalized to simulate moving multibody sections in the complex vertical flows and forces experienced by the blades. Finally the fast semi analytical aerodynamic algorithm boosted by fast multipole methods to handle high number of vortices is coupled with a simple structural model of the rotor to investigate potential aeroelastic instabilities. Together with these advanced simulation tools, a standard double multiple streamtube model has been developed and used to design several straight bladed

  8. DARHT Axis-I Diode Simulations II: Geometrical Scaling

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A. Jr. [Los Alamos National Laboratory

    2012-06-14

    Flash radiography of large hydrodynamic experiments driven by high explosives is a venerable diagnostic technique in use at many laboratories. Many of the largest hydrodynamic experiments study mockups of nuclear weapons, and are often called hydrotests for short. The dual-axis radiography for hydrodynamic testing (DARHT) facility uses two electron linear-induction accelerators (LIA) to produce the radiographic source spots for perpendicular views of a hydrotest. The first of these LIAs produces a single pulse, with a fixed {approx}60-ns pulsewidth. The second axis LIA produces as many as four pulses within 1.6-{micro}s, with variable pulsewidths and separation. There are a wide variety of hydrotest geometries, each with a unique radiographic requirement, so there is a need to adjust the radiographic dose for the best images. This can be accomplished on the second axis by simply adjusting the pulsewidths, but is more problematic on the first axis. Changing the beam energy or introducing radiation attenuation also changes the spectrum, which is undesirable. Moreover, using radiation attenuation introduces significant blur, increasing the effective spot size. The dose can also be adjusted by changing the beam kinetic energy. This is a very sensitive method, because the dose scales as the {approx}2.8 power of the energy, but it would require retuning the accelerator. This leaves manipulating the beam current as the best means for adjusting the dose, and one way to do this is to change the size of the cathode. This method has been proposed, and is being tested. This article describes simulations undertaken to develop scaling laws for use as design tools in changing the Axis-1 beam current by changing the cathode size.

  9. The manufacturing and metrology of off-axis mirrors

    Science.gov (United States)

    Penzkofer, Karlheinz; Rascher, Rolf; Küpper, Lutz; Liebl, Johannes

    2015-10-01

    Especially in the area of the large mirror manufacturing only a few manufacturers are capable to produce optical surfaces of high quality. Therefore a deterministic process should be developed in the project IFasO. In the field of telescope optics off-axis optical systems are becoming increasingly important. These systems try to avoid an obstructing of the incoming light by moving the secondary mirror out of the primary mirror's optical axis. This advantage leads to an increasing market for this type of optical surface. Until now off-axis mirrors were difficult or almost impossible to produce. With the processes developed in IFasO, high quality mirrors become possible. For this reason, this paper describes the manufacturing of off-axis surfaces and its problems. The mirror production used in the project IFasO is based on the specific design of the CNC center developed by the company Optotech. This center UPG2000 is capable of grinding, polishing, sagitta measurement and interferometric measurement in one mounting of the specimen. Usually a large optics has to be transported during their manufacturing after every individual process step. There is always a risk of damage of the specimen. The exact orientation of the surface relatively to the tool position is also required. This takes a huge amount of time and makes up most of the production time. In this presentation the use of UPG2000 and the next steps within the process development are described. In the current status the manufacturing of large off-axis elements with a PV < λ/10 rms is reproducible.

  10. Velocity measurement of model vertical axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.A.; McWilliam, M. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering

    2006-07-01

    An increasingly popular solution to future energy demand is wind energy. Wind turbine designs can be grouped according to their axis of rotation, either horizontal or vertical. Horizontal axis wind turbines have higher power output in a good wind regime than vertical axis turbines and are used in most commercial class designs. Vertical axis Savonius-based wind turbine designs are still widely used in some applications because of their simplistic design and low wind speed performance. There are many design variables that must be considered in order to optimize the power output in a given wind regime in a typical wind turbine design. Using particle image velocimetry, a study of the air flow around five different model vertical axis wind turbines was conducted in a closed loop wind tunnel. A standard Savonius design with two semi-circular blades overlapping, and two variations of this design, a deep blade and a shallow blade design were among the turbine models included in this study. It also evaluated alternate designs that attempt to increase the performance of the standard design by allowing compound blade curvature. Measurements were collected at a constant phase angle and also at random rotor orientations. It was found that evaluation of the flow patterns and measured velocities revealed consistent and stable flow patterns at any given phase angle. Large scale flow structures are evident in all designs such as vortices shed from blade surfaces. An important performance parameter was considered to be the ability of the flow to remain attached to the forward blade and redirect and reorient the flow to the following blade. 6 refs., 18 figs.

  11. DESIGN NOTE: A low interaction two-axis wind tunnel force balance designed for large off-axis loads

    Science.gov (United States)

    Ostafichuk, Peter M.; Green, Sheldon I.

    2002-10-01

    A novel two-axis wind tunnel force balance using air bushings for off-axis load compensation has been developed. The design offers a compact, robust, and versatile option for precisely measuring horizontal force components irrespective of vertical and moment loads. Two independent stages of cylindrical bushings support large moments and vertical force; there is low interaction due to the minimal friction along the horizontal measurement axes. The current design measures drag and side forces up to 70 N and can safely operate in the presence of vertical loads as large as 2200 N and moment loads up to 425, 750, and 425 N m in roll, pitch, and yaw, respectively. Eleven drag axis calibration trials were conducted with a variety of applied vertical forces and pitching moments. The individual linear calibration slopes for the trials agreed to within 0.18% and the largest residual from all calibrations was 0.38% of full scale. As the residuals were found to obey a normal distribution, with 99% certainty the expected drag resolution of the device is better than 0.30% of full scale, independent of off-axis loads.

  12. Tuning the DARHT Axis-II linear induction accelerator focusing

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A. [Los Alamos National Laboratory

    2012-04-24

    Flash radiography of large hydrodynamic experiments driven by high explosives is a well-known diagnostic technique in use at many laboratories, and the Dual-Axis Radiography for Hydrodynamic Testing (DARHT) facility at Los Alamos produces flash radiographs of large hydrodynamic experiments. Two linear induction accelerators (LIAs) make the bremsstrahlung radiographic source spots for orthogonal views of each test. The 2-kA, 20-MeV Axis-I LIA creates a single 60-ns radiography pulse. The 1.7-kA, 16.5-MeV Axis-II LIA creates up to four radiography pulses by kicking them out of a longer pulse that has a 1.6-{mu}s flattop. The Axis-II injector, LIA, kicker, and downstream transport (DST) to the bremsstrahlung converter are described. Adjusting the magnetic focusing and steering elements to optimize the electron-beam transport through an LIA is often called 'tuning.' As in all high-current LIAs, the focusing field is designed to be as close to that of the ideal continuous solenoid as physically possible. In ideal continuous solenoidal transport a smoothly varying beam size can easily be found for which radial forces balance, and the beam is said to be 'matched' to the focusing field. A 'mismatched' beam exhibits unwanted oscillations in size, which are a source of free energy that contributes to emittance growth. This is undesirable, because in the absence of beam-target effects, the radiographic spot size is proportional to the emittance. Tuning the Axis-II LIA is done in two steps. First, the solenoidal focusing elements are set to values designed to provide a matched beam with little or no envelope oscillations, and little or no beam-breakup (BBU) instability growth. Then, steering elements are adjusted to minimize the motion of the centroid of a well-centered beam at the LIA exit. This article only describes the design of the tune for the focusing solenoids. The DARHT Axis-II LIA was required to be re-tuned after installing an

  13. Psychiatric Axis I Comorbidities among Patients with Gender Dysphoria

    Directory of Open Access Journals (Sweden)

    Azadeh Mazaheri Meybodi

    2014-01-01

    Full Text Available Objectives. Cooccurring psychiatric disorders influence the outcome and prognosis of gender dysphoria. The aim of this study is to assess psychiatric comorbidities in a group of patients. Methods. Eighty-three patients requesting sex reassignment surgery (SRS were recruited and assessed through the Persian Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I. Results. Fifty-seven (62.7% patients had at least one psychiatric comorbidity. Major depressive disorder (33.7%, specific phobia (20.5%, and adjustment disorder (15.7% were the three most prevalent disorders. Conclusion. Consistent with most earlier researches, the majority of patients with gender dysphoria had psychiatric Axis I comorbidity.

  14. Development of the adrenal axis in the neonatal rat

    Energy Technology Data Exchange (ETDEWEB)

    Guillet, Ronnie

    1977-01-01

    Plasma corticosterone and ACTH concentrations were determined in neonatal rats 1, 7, 14, and 21 days old, under a variety of experimental conditions, to obtain more information on the postnatal development of the rat hypothalamo-adrenal (HHA) axis. The results indicate that: (1) there is a diminution followed by an increase in responsiveness of the adrenal gland, but the pituitary response to direct hormonal stimulation is unchanged during the first three postnatal weeks; (2) continued stimulation of the adrenal by ACTH or of the central nervous system (CNS) or hypothalamus by corticosterone is necessary during early postnatal development to allow normal maturation of the HHA axis; and (3) feedback inhibition is operative by birth, at least to a moderate degree. Taken together, the studies suggest that both the adrenal and pituitary glands are potentially functional at birth, but that the hypothalamic and CNS mediators of the stress response are not mature until at least the second or third postnatal week. (ERB)

  15. A new vertical axis wind turbine design for urban areas

    Science.gov (United States)

    Frunzulica, Florin; Cismilianu, Alexandru; Boros, Alexandru; Dumitrache, Alexandru; Suatean, Bogdan

    2016-06-01

    In this paper we aim at developing the model of a Vertical Axis Wind Turbine (VAWT) with the short-term goal of physically realising this turbine to operate at a maximmum power of 5 kW. The turbine is designed for household users in the urban or rural areas and remote or isolated residential areas (hardly accsessible). The proposed model has a biplane configuration on each arm of the VAWT (3 × 2 = 6 blades), allowing for increased performance of the turbine at TSR between 2 and 2.5 (urban area operation) compared to the classic vertical axis turbines. Results that validate the proposed configuration as well as passive control methods to increase the performance of the classic VAWTs are presented.

  16. Application of one-axis sun tracking system

    International Nuclear Information System (INIS)

    This paper introduces design and application of a novel one-axis sun tracking system which follows the position of the sun and allows investigating effects of one-axis tracking system on the solar energy in Turkey. The tracking system includes a serial communication interface based on RS 485 to monitor whole processes on a computer screen and to plot data as graphic. In addition, system parameters such as the current, the voltage and the panel position have been observed by means of a microcontroller. The energy collected is measured and compared with a fixed solar system for the same solar panel. The results show that the solar energy collected on the tracking system is considerably much efficient than the fixed system. The tracking system developed in this study provides easy installation, simple mechanism and less maintenance.

  17. Design optimization and analysis of vertical axis wind turbine blade

    International Nuclear Information System (INIS)

    Wind energy is clean and renwable source of energy and is also the world's fastest growing energy resource. Keeping in view power shortages and growing cost of energy, the low cost wind energy has become a primary solution. It is imperative that economies and individuals begin to conserve energy and focus on the production of energy from renewable sources. Present study describes a wind turbine blade designed with enhanced aerodynamic properties. Vertical axis turbine is chosen because of its easy installment, less noisy and having environmental friendly characteristics. Vertical axis wind turbines are thought to be ideal for installations where wind conditions are not consistent. The presented turbine blade is best suitable for roadsides where the rated speed due to vehicles is most /sup -1/ often 8 ms .To get an optimal shape design symmetrical profile NACA0025 has been considered which is then analyzed for stability and aerodynamic characteristics at optimal conditions using analysis tools ANSYS and CFD tools. (author)

  18. A single-axis testbed for slewing control experiments

    Science.gov (United States)

    Hamilton, Jonathan; Lee, Gordon K. F.; Juang, Jer-Nan

    1990-01-01

    A simple single-axis testbed is described, and initial experimental results are presented to illustrate collocated and noncollocated control for this structure. The testbed is made up of a pair of single-axis flexible beams attached to a DC servo motor. An optical encoder and strain gauges provide hub and beam position information, respectively. The system is driven by an IBM PC system; with a motor controller, a programmable digital filter processes position error information through user-selected gains and pole-zero configurations. A 25-kHz data acquisition system provides the necessary interface between processor and motor. The control approaches currently being investigated include collocated PD control and noncollocated phase compensation.

  19. Jet maximization, axis minimization, and stable cone finding

    Science.gov (United States)

    Thaler, Jesse

    2015-10-01

    Jet finding is a type of optimization problem, where hadrons from a high-energy collision event are grouped into jets based on a clustering criterion. As three interesting examples, one can form a jet cluster that (i) optimizes the overall jet four-vector, (ii) optimizes the jet axis, or (iii) aligns the jet axis with the jet four-vector. In this paper, we show that these three approaches to jet finding, despite being philosophically quite different, can be regarded as descendants of a mother optimization problem. For the special case of finding a single cone jet of fixed opening angle, the three approaches are genuinely identical when defined appropriately, and the result is a stable cone jet with the largest value of a quantity J . This relationship is only approximate for cone jets in the rapidity-azimuth plane, as used at the Large Hadron Collider, though the differences are mild for small radius jets.

  20. Summary of tower designs for large horizontal axis wind turbines

    Science.gov (United States)

    Frederick, G. R.; Savino, J. M.

    1986-01-01

    Towers for large horizontal axis wind turbines, machines with a rotor axis height above 30 meters and rated at more than 500 kW, have varied in configuration, materials of construction, type of construction, height, and stiffness. For example, the U.S. large HAWTs have utilized steel truss type towers and free-standing steel cylindrical towers. In Europe, the trend has been to use only free-standing and guyed cylindrical towers, but both steel and reinforced concrete have been used as materials of construction. These variations in materials of construction and type of construction reflect different engineering approaches to the design of cost effective towers for large HAWTs. Tower designs are the NASA/DOE Mod-5B presently being fabricated. Design goals and requirements that influence tower configuration, height and materials are discussed. In particular, experiences with United States large wind turbine towers are elucidated. Finally, current trends in tower designs for large HAWTs are highlighted.

  1. Effects of structure flexibility on horizontal axis wind turbine performances

    Science.gov (United States)

    Coiro, D. P.; Daniele, E.; Scherillo, F.

    2013-10-01

    This work illustrates the effects of flexibility of rotor blades and turbine tower on the performances of an horizontal axis wind turbine (HAWT) designed by our ADAG research group, by means of several example applied on a recent project for a active pitch controlled upwind 60 kW HAWT. The influence of structural flexibility for blade only, tower only and blade coupled with tower configuration is investigated using an aero-elastic computer-aided engineering (CAE) tool for horizontal axis wind turbines named FAST developed at National Renewable Energy Laboratory (NREL) of USA. For unsteady inflow conditions in front of the isolated HAWT the performances in rigid and flexible operation mode are computed and compared in order to illustrate the limitation included within a classical rigid body approach to wind turbine simulation.

  2. Early programming of the IGF-I axis

    DEFF Research Database (Denmark)

    Larnkjær, Anni; Ingstrup, Helga Kristensen; Schack-Nielsen, Lene;

    2009-01-01

    -I production. Conversely, studies suggest that later in childhood, those breastfed are taller and have higher IGF-I levels. Therefore, it has been suggested that the IGF-I axis may be programmed by diet during infancy. The association between IGF-I in infancy and later life is not known. OBJECTIVE: To examine...... for gender, breastfeeding, and other covariates. Likelihood ratio test based on residual log likelihood was applied for analysis including all measurements during infancy. RESULTS: There was an inverse association between IGF-I at 9 months and 17 years (r=-0.39, P=0.014, and n=40). A 1 ng/ml higher IGF......=-0.26, P=0.043, and n=109). CONCLUSION: The results support the hypothesis that the IGF-I axis can be programmed early in life....

  3. Off-axis Fresnel numbers in laser systems

    Institute of Scientific and Technical Information of China (English)

    Yudong; Yao; Junyong; Zhang; Yanli; Zhang; Qunyu; Bi; Jianqiang; Zhu

    2014-01-01

    The physical meaning and essence of Fresnel numbers are discussed,and two definitions of these numbers for offaxis optical systems are proposed.The universal Fresnel number is found to be N =(a2/λz) * C1+ C2.The Rayleigh–Sommerfeld nonparaxial diffraction formula states that a simple analytical formula for the nonparaxial intensity distribution after a circular aperture can be obtained.Theoretical derivations and numerical calculations reveal that the first correction factor C1 is equal to cos θ and the second factor C2 is a function of the incident wavefront and the shape of the diffractive aperture.Finally,some diffraction phenomena in off-axis optical systems are explained by the off-axis Fresnel number.

  4. Electrostatic levitation under the single-axis feedback control condition

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An electrostatic levitator with a single-axis feedback control system was developed on the basis of electric field analysis and optimum design for levitation electrodes. In order to realize the stable levitation of various types of materials such as metals, inorganic materials and polymers, we made both experimental and theoretical investigations to solve the four key problems of electric field optimization, sample position detecting, sample charging control and levitation voltage minimization. Under the capacitive induction charging condition, a sample with the size of 2.6–4.5 mm usually bears positive charges amounting to 10-9 Coulomb. Because the single-axis feedback control system responds quickly, it takes the levitated sample only 0.1 s from leaving the bottom electrode until attaining a stable levitation in the upright direction. The levitated sample displays satisfactory levitation stability in both the upright and the horizontal directions owing to the constraining force produced by spherical electrodes.

  5. Psychiatric Axis I Comorbidities among Patients with Gender Dysphoria

    Science.gov (United States)

    Hajebi, Ahmad

    2014-01-01

    Objectives. Cooccurring psychiatric disorders influence the outcome and prognosis of gender dysphoria. The aim of this study is to assess psychiatric comorbidities in a group of patients. Methods. Eighty-three patients requesting sex reassignment surgery (SRS) were recruited and assessed through the Persian Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). Results. Fifty-seven (62.7%) patients had at least one psychiatric comorbidity. Major depressive disorder (33.7%), specific phobia (20.5%), and adjustment disorder (15.7%) were the three most prevalent disorders. Conclusion. Consistent with most earlier researches, the majority of patients with gender dysphoria had psychiatric Axis I comorbidity. PMID:25180172

  6. The Wake of a Single Vertical Axis Wind Turbine

    Science.gov (United States)

    Barsky, Danielle

    Vertical axis wind turbines (VAWTs) pose various advantages over traditional horizontal axis wind turbines (HAWTs), including their smaller size and footprint, quiet operation, and ability to produce power under a greater variety of wind directions and wind speeds. To determine the optimal spacing of an array of VAWTs for maximum power output, an understanding of the fundamental wake structure of a single VAWT is needed. This study is among the first attempts to experimentally visualize the wake of a VAWT using stereo particle image velocimetry (PIV). A scale VAWT is placed inside a wind tunnel and a motor rotates the scale model at a constant rotational speed. Wake data at several Reynolds numbers and tip speed ratios indicate that vortices are shed by each blade of the spinning VAWT, demonstrating significant differences between the wake of a VAWT and a spinning cylinder.

  7. Flow-blade interaction in a Vertical Axis Wind Turbine

    Science.gov (United States)

    Dominguez, Roberto; Piedra, Saul; Ramos, Eduardo

    2014-11-01

    We present an analysis of the interaction between an incoming wind and three airfoils symmetrically located, and free to rotate around a common axis. The geometrical configuration considered is a two dimensional model of Vertical Axis Wind Turbine. The model is based in the conservation equations of the fluid coupled with the Newton-Lagrange equations for the interaction with the airfoils. The presence of the rigid body in the fluid is simulated using immersed boundary conditions. The interaction of the wind with the airfoil located further upstream generates a force on the airfoil and vortices that are swept downstream and collide with the other airfoils. This effect generates a complex interplay of dynamical forces whose resultant is a torque that sets the system in motion. We describe the flow around the airfoils and examine the efficiency of the system as a function of geometric variables. Our conclusions are potentially useful for the design of VAWT's.

  8. The axis of orientation of the synlophe in the Heligmosomoidea (Nematoda, Trichostrongylina: a new approach

    Directory of Open Access Journals (Sweden)

    Durette-Desset M.C.

    2005-09-01

    Full Text Available The definition of the axis of orientation of the synlophe is modified for the Heligmosomoidea so that one or two axes may be recognized. When two axes are present, their inclinations to the sagittal axis are different on the right and left sides, and we propose to name them right axis and left axis, respectively. During the course of evolution, starting from a single oblique axis (plesiomorphic state, an independent rotation of this axis on the right and left sides may bring about a double-axis state with a different inclination on both sides (derived state. When the rotation reaches 90° for both sides, the axis becomes simple once again and is superimposed to the frontal axis (most derived state.

  9. Kinematical smoothing of rotary axis near singularity point

    OpenAIRE

    Grandguillaume, Laureen; Lavernhe, Sylvain; Tournier, Christophe

    2015-01-01

    This paper deals with singular configurations of a 5-axis machine tool in high speed milling which may lead to the appearance of large incoherent movements of rotary axes near singularity points. These movements generate slowdowns of the actual feedrate during the execution of the tool path, which affect quality and productivity. Thus, this paper proposes a method to detect these behaviors during machining simulation and correct the tool path. Unlike the literature methods, this correction co...

  10. Social Deprivation and the HPA Axis in Early Development

    OpenAIRE

    Koss, Kalsea J; Hostinar, Camelia E.; Donzella, Bonny; Gunnar, Megan R.

    2014-01-01

    Growing evidence suggests that early social deprivation impacts the activity of the hypothalamic-pituitary-adrenocortical axis. Early adverse care in the form of institutional or orphanage care provides a human model for early social deprivation. The present study examined changes in diurnal cortisol during the transition to family care in the first two years post-adoption. Children adopted between 15 and 36 months from institutional care were examined four times during thei...

  11. Dynamic behavior analysis for a six axis industrial machining robot

    OpenAIRE

    Bisu, Claudiu-Florinel; Cherif, Medhi; Gérard, Alain; K'Nevez, Jean-Yves

    2012-01-01

    The six axis robots are widely used in automotive industry for their good repeatability (as defined in the ISO92983) (painting, welding, mastic deposition, handling etc.). In the aerospace industry, robot starts to be used for complex applications such as drilling, riveting, fiber placement, NDT, etc. Given the positioning performance of serial robots, precision applications require usually external measurement device with complexes calibration procedure in order to reach the precision needed...

  12. Development of Rotary Axis for Wire Electrical Discharge Machining (WEDM)

    OpenAIRE

    M. Parthiban, C. Manigandan, G. Muthu Venkadesh, M. Ranjith Kumar

    2013-01-01

    This paper gives an overview of setting up a rotary axis to the existing WEDM machine to investigate the machining parameters in WEDG of harder materials. There are a number of hybrid machining processes (HMPs) seeking the combined advantage of EDM and other machining techniques. One such combination is wire electrical discharge grinding (WEDG), which is commonly used for micro-machining of fine and hard rods. WEDG employs a single wire guide to confine the wir...

  13. Vessel Axis Tracking Using Topology Constrained Surface Evolution

    OpenAIRE

    Manniesing, Rashindra; Viergever, M A; Niessen, Wiro

    2007-01-01

    textabstractAn approach to three-dimensional vessel axis tracking based on surface evolution is presented. The main idea is to guide the evolution of the surface by analyzing its skeleton topology during evolution, and imposing shape constraints on the topology. For example, the intermediate topology can be processed such that it represents a single vessel segment, a bifurcation, or a more complex vascular topology. The evolving surface is then re-initialized with the newly found topology. Re...

  14. Targeting the gut-liver axis in cirrhosis

    DEFF Research Database (Denmark)

    Madsen, Bjørn S; Havelund, Troels; Krag, Aleksander

    2013-01-01

    The gut-liver axis in cirrhosis and portal hypertension is gaining increasing attention as a key pathophysiological mechanism responsible for progression of liver failure and development of complications such as spontaneous infections and hepatocellular carcinoma. Antibiotics and non-selective β...... the issue of pharmacological treatment of cirrhosis and portal hypertension with antibiotics and NSBB. We discuss their mechanism of action and suggest that combining the two treatment modalities could potentially reduce the risk of complications....

  15. Resonance Shift of Single-Axis Acoustic Levitation

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Jun; WEI Bing-Bo

    2007-01-01

    @@ The resonance shift due to the presence and movement of a rigid spherical sample in a single-axis acoustic levitator is studied with the boundary element method on the basis of a two-cylinder model of the levitator.The introduction of a sample into the sound pressure nodes, where it is usually levitated, reduces the resonant interval Hn (n is the mode number) between the reflector and emitter.

  16. Dual-axis MEMS force sensors for gecko adhesion studies

    Science.gov (United States)

    Hill, Ginel Corina

    Dual-axis piezoresistive microelectromechanical systems (MEMS) force sensors were used to investigate the effects of orientation angle on the adhesion of gecko hairs, called setae. These hairs are part of a fantastic, robust dry adhesive. Their adhesion is highly angle-dependent, with both the "pitch" and "roll" orientation angles playing a role. This anisotropy in adhesion properties is critical for locomotion, as it enables detachment of the gecko's foot with limited pull-off force. Many synthetic mimics of the gecko adhesive are isotropic. This work on the anisotropy of natural setae will inform future work on synthetic dry adhesives. A dual-axis microscale force sensor was needed to study single seta adhesive forces, which are stronger parallel to a substrate than perpendicular. Piezoresistive silicon cantilevers that separately detect lateral and normal forces applied at the tip were used. The fabrication process and rigorous characterization of new devices are reported. A novel calibration method was developed that uses resonant frequency measurements in concert with finite element models to correct for the expected variability of critical dimensions. These corrected models were used to predict the stiffnesses of each cantilever, and thus improve the accuracy of force measurements made with these sensors. This calibration technique was also validated by direct measurement of the dual-axis cantilever stiffnesses using a reference cantilever. The adhesion force of a single gecko seta is dramatically enhanced by proper orientation. The dual-axis cantilevers were used to measure two components of force between a substrate and a Gekko gecko seta. Lateral adhesion was highest with the stalk oriented parallel to the surface at 0° pitch. Adhesion decreased smoothly as the pitch angle of the stalk was increased, until detachment or no adhesion occurred at approximately 30°. To display enhanced adhesion, the splayed tuft at the end of the seta needed to be only

  17. Psychiatric Axis I Comorbidities among Patients with Gender Dysphoria

    OpenAIRE

    Azadeh Mazaheri Meybodi; Ahmad Hajebi; Atefeh Ghanbari Jolfaei

    2014-01-01

    Objectives. Cooccurring psychiatric disorders influence the outcome and prognosis of gender dysphoria. The aim of this study is to assess psychiatric comorbidities in a group of patients. Methods. Eighty-three patients requesting sex reassignment surgery (SRS) were recruited and assessed through the Persian Structured Clinical Interview for DSM-IV Axis I disorders (SCID-I). Results. Fifty-seven (62.7%) patients had at least one psychiatric comorbidity. Major depressive disorder (33.7%), speci...

  18. 6-Axis Force/Moment Sensor In Humanoid Robot Foot

    Science.gov (United States)

    Ai-Faifi, Badrih; Al-Shammary, Maryam; Al-Shehry, Zinab

    2014-07-01

    The foot is the most Important part of the humanoid .Thought the sensor of the robot can understand the environment In which they live, it is important to developed an intelligent foot. In order to walk on uneven terrain safely this poster describes an intelligent foot with 6- axis force/moment sensors for humanoid robot that is one of the solution that can help the robot to walk in uneven terrain safely.

  19. Bendability optimization of flexible optical nanoelectronics via neutral axis engineering

    OpenAIRE

    Lee, Sangmin; Kwon, Jang-Yeon; Yoon, Daesung; Cho, Handong; You, Jinho; Kang, Yong Tae; Choi, Dukhyun; Hwang, Woonbong

    2012-01-01

    The enhancement of bendability of flexible nanoelectronics is critically important to realize future portable and wearable nanoelectronics for personal and military purposes. Because there is an enormous variety of materials and structures that are used for flexible nanoelectronic devices, a governing design rule for optimizing the bendability of these nanodevices is required. In this article, we suggest a design rule to optimize the bendability of flexible nanoelectronics through neutral axi...

  20. Inversion of the chordate body axis: are there alternatives?

    Science.gov (United States)

    Gerhart, J.

    2000-01-01

    One major morphological difference between chordates and annelids or arthropods is the opposite orientation of the nerve cord and heart. A long-standing proposal is that the chordate axis evolved by inverting the body of an ancestor with the annelid/arthropod orientation. However, the data can also be explained by a common ancestor with diffuse dorsoventral organization, followed by oppositely directed condensation of the nerve cord and relocation of the heart in the two lines.

  1. Inversion of the chordate body axis: Are there alternatives?

    OpenAIRE

    Gerhart, J.

    2000-01-01

    One major morphological difference between chordates and annelids or arthropods is the opposite orientation of the nerve cord and heart. A long-standing proposal is that the chordate axis evolved by inverting the body of an ancestor with the annelid/arthropod orientation. However, the data can also be explained by a common ancestor with diffuse dorsoventral organization, followed by oppositely directed condensation of the nerve cord and relocation of the heart in the t...

  2. Neuropeptides and the Microbiota-Gut-Brain Axis

    OpenAIRE

    Holzer, Peter; Farzi, Aitak

    2014-01-01

    Neuropeptides are important mediators both within the nervous system and between neurons and other cell types. Neuropeptides such as substance P, calcitonin gene-related peptide and neuropeptide Y (NPY), vasoactive intestinal polypeptide, somatostatin and corticotropin-releasing factor are also likely to play a role in the bidirectional gut-brain communication. In this capacity they may influence the activity of the gastrointestinal microbiota and its interaction with the gut-brain axis. Curr...

  3. The Parameters Affect on Power Coefficient Vertical Axis Wind Turbine

    OpenAIRE

    2012-01-01

    ABSTRACT: This study describes the design of a special type of vertical axis rotor wind turbine with moveable vertically positioned vanes. The novel design increases the torque in the left side of the wind turbine by increasing the drag coefficient. It also reduces the negative torque of the frame which rotates contrary to the wind in the other side. Two different types of models, having different vane shapes (flat vane and cavity shaped vane), were fabricated. Each type consisted of two mode...

  4. The method of isolines for the shower axis determination

    OpenAIRE

    Kirov, I. N.; Stamenov, J. N.

    2006-01-01

    The method of isolines (contours) is proposed to be used for deter- mination of core location of extensive air shower on the array plane. As variable z=f(x,y) are used flux densities of particles, registrated from ground detectors. Obtained isolines are approximated with circles, which centers show impact point of shower axis. The method was demostrated on experimental data from Tien-Shan shower array in period 1974-82. The possibilities and difficulties of the method are discussed.

  5. CFD Simulation of Twin Vertical Axis Tidal Turbines System

    OpenAIRE

    Syed Shah Khalid; Zhang Liang; Sheng Qi-hu

    2013-01-01

    As concerns about rising fossil-fuel prices, energy security and climate-change increase, renewable energy can play a vital role in producing local, clean and inexhaustible energy to supply world rising demand for electricity. In this study, hydrodynamic analysis of vertical axis tidal turbine operating side-by-side is numerically analyzed. Two-dimensional numerical modeling of the unsteady flow through the blades of the turbine is performed using ANSYS CFX, hereafter CFX; this is based on a ...

  6. Multi axis differential optical absorption spectroscopy (MAX-DOAS)

    OpenAIRE

    Hönninger, G.; Von Friedeburg, C.; U. Platt

    2004-01-01

    Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the atmosphere is a novel measurement technique that represents a significant advance on the well-established zenith scattered sunlight DOAS instruments which are mainly sensitive to stratospheric absorbers. MAX-DOAS utilizes scattered sunlight received from multiple viewing directions. The spatial distribution of various trace gases close to the instrument can be derived by combining several viewing directions. Ground...

  7. Multi axis differential optical absorption spectroscopy (MAX-DOAS)

    OpenAIRE

    Hönninger, G.; Friedeburg, C.; U. Platt

    2004-01-01

    Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) in the atmosphere is a novel measurement technique that represents a significant advance on the well-established zenith scattered sunlight DOAS instruments which are mainly sensitive to stratospheric absorbers. MAX-DOAS utilizes scattered sunlight received from multiple viewing directions. The spatial distribution of various trace gases close to the instrument can be derived by combining sev...

  8. Estimation of power in low velocity vertical axis wind turbine

    Science.gov (United States)

    Sampath, S. S.; Shetty, Sawan; Chithirai Pon Selvan, M.

    2015-06-01

    The present work involves in the construction of a vertical axis wind turbine and the determination of power. Various different types of turbine blades are considered and the optimum blade is selected. Mechanical components of the entire setup are built to obtain maximum rotation per minute. The mechanical energy is converted into the electrical energy by coupling coaxially between the shaft and the generator. This setup produces sufficient power for consumption of household purposes which is economic and easily available.

  9. The reno-pineal axis: A novel role for melatonin

    OpenAIRE

    Sanjay Kalra; Swati Agrawal; Manisha Sahay

    2012-01-01

    The pineal gland is a tiny endocrine gland whose physiologic role has been the focus of much research and much more speculation over the past century. This mini-review discusses recent findings which correlate melatonin and renal physiology, and postulates the presence of a “reno-pineal axis.” Drawing lessons from comparative endocrinology, while quoting human data, it advocates the need to study the “reno-pineal axis” in greater detail.

  10. Maternal control of the Drosophila dorsal–ventral body axis

    OpenAIRE

    Stein, David S.; Stevens, Leslie M.

    2014-01-01

    The pathway that generates the dorsal–ventral (DV) axis of the Drosophila embryo has been the subject of intense investigation over the previous three decades. The initial asymmetric signal originates during oogenesis by the movement of the oocyte nucleus to an anterior corner of the oocyte, which establishes DV polarity within the follicle through signaling between Gurken, the Drosophila Transforming Growth Factor (TGF)-α homologue secreted from the oocyte, and the Drosophila Epidermal Growt...

  11. Design, Operation and Diagnostics of a Vertical Axis Wind Turbine

    OpenAIRE

    Colley, Gareth

    2012-01-01

    The need for sustainable energy sources becomes greater each year due to the continued depletion of fossil fuels and the resulting energy crisis. Solutions to this problem are potentially in the form of wind turbines which have been receiving increased support at a micro level. At present a number of wind turbines are being developed that are of cross-flow vertical axis operation which have shown significant increases in performance compared to existing technologies. From an extensive literat...

  12. Towards the Evolution of Novel Vertical-Axis Wind Turbines

    OpenAIRE

    Preen, Richard J.; Bull, Larry

    2012-01-01

    Renewable and sustainable energy is one of the most important challenges currently facing mankind. Wind has made an increasing contribution to the world's energy supply mix, but still remains a long way from reaching its full potential. In this paper, we investigate the use of artificial evolution to design vertical-axis wind turbine prototypes that are physically instantiated and evaluated under approximated wind tunnel conditions. An artificial neural network is used as a surrogate model to...

  13. Study of axis-symmetry for judgement on nuclear parts

    International Nuclear Information System (INIS)

    In this paper, gamma-ray distributions from nuclear weapon parts of different shapes are simulated. The gamma-rays from a cylinder nuclear part have axis-symmetry distribution, while the gamma-rays from prism nuclear parts are of asymmetry distribution. The quadra- and penta-prism distributions differ obviously from that of the cylinder. However, the asymmetry of hexa-, octo- and dodeca-prism reduces gradually to approach to the symmetry distribution of the cylinder. (authors)

  14. Orthogonal Analysis Based Performance Optimization for Vertical Axis Wind Turbine

    OpenAIRE

    Lei Song; Hong-Zhao Liu; Zong-Xiao Yang

    2016-01-01

    Geometrical shape of a vertical axis wind turbine (VAWT) is composed of multiple structural parameters. Since there are interactions among the structural parameters, traditional research approaches, which usually focus on one parameter at a time, cannot obtain performance of the wind turbine accurately. In order to exploit overall effect of a novel VAWT, we firstly use a single parameter optimization method to obtain optimal values of the structural parameters, respectively, by Computational ...

  15. Aerodynamic Analysis Models for Vertical-Axis Wind Turbines

    OpenAIRE

    Brahimi, M. T.; A. Allet; I. Paraschivoiu

    1995-01-01

    This work details the progress made in the development of aerodynamic models for studying Vertical-Axis Wind Turbines (VAWT's) with particular emphasis on the prediction of aerodynamic loads and rotor performance as well as dynamic stall simulations. The paper describes current effort and some important findings using streamtube models, 3-D viscous model, stochastic wind model and numerical simulation of the flow around the turbine blades. Comparison of the analytical results with available e...

  16. Vertical axis wind turbine in a falling soap film

    OpenAIRE

    Araya, Daniel B.; Dabiri, John O.

    2015-01-01

    Vertical axis wind turbines (VAWTs) have demonstrated a potential to significantly enhance the efficiency of energy harvesting within a wind farm. One mechanism that contributes to this enhancement is a VAWT’s inherent insensitivity to wind direction coupled with blockage within an array of turbines. Much like the flow around a bluff body, turbine blockage can locally accelerate the flow near one turbine, providing faster inflow conditions for a well-placed neighboring turbine. Since the powe...

  17. Reliability of floating foundation concepts for vertical axis wind turbines

    OpenAIRE

    Athanasios J. Kolios; Collu, Maurizio; Brennan, Feargal P.

    2010-01-01

    Offshore wind turbines are developing at a rapid pace. By far the most common turbine configuration is the HAWT (Horizontal Axis Wind Turbine) and development of these machines is largely centered about drive train and blade issues with some work concerning foundations/ supporting structures. Several teams around the world are developing floating supporting structures for HAWT, mainly for deep water deployment. This paper describes the development of a floating support structure for Vertical ...

  18. MARRT: Medial Axis biased rapidly-exploring random trees

    KAUST Repository

    Denny, Jory

    2014-05-01

    © 2014 IEEE. Motion planning is a difficult and widely studied problem in robotics. Current research aims not only to find feasible paths, but to ensure paths have certain properties, e.g., shortest or safest paths. This is difficult for current state-of-the-art sampling-based techniques as they typically focus on simply finding any path. Despite this difficulty, sampling-based techniques have shown great success in planning for a wide range of applications. Among such planners, Rapidly-Exploring Random Trees (RRTs) search the planning space by biasing exploration toward unexplored regions. This paper introduces a novel RRT variant, Medial Axis RRT (MARRT), which biases tree exploration to the medial axis of free space by pushing all configurations from expansion steps towards the medial axis. We prove that this biasing increases the tree\\'s clearance from obstacles. Improving obstacle clearance is useful where path safety is important, e.g., path planning for robots performing tasks in close proximity to the elderly. Finally, we experimentally analyze MARRT, emphasizing its ability to effectively map difficult passages while increasing obstacle clearance, and compare it to contemporary RRT techniques.

  19. Vasoactive intestinal peptide signaling axis in human leukemia

    Institute of Scientific and Technical Information of China (English)

    Glenn; Paul; Dorsam; Keith; Benton; Jarrett; Failing; Sandeep; Batra

    2011-01-01

    The vasoactive intestinal peptide (VIP) signaling axis constitutes a master "communication coordinator" between cells of the nervous and immune systems.To date,VIP and its two main receptors expressed in T lymphocytes,vasoactive intestinal peptide receptor (VPAC)1 and VPAC2,mediate critical cellular functions regulating adaptive immunity,including arresting CD4 T cells in G 1 of the cell cycle,protection from apoptosis and a potent chemotactic recruiter of T cells to the mucosa associated lymphoid compartment of the gastrointestinal tissues.Since the discovery of VIP in 1970,followed by the cloning of VPAC1 and VPAC2 in the early 1990s,this signaling axis has been associated with common human cancers,including leukemia.This review highlights the present day knowledge of the VIP ligand and its receptor expression profile in T cell leukemia and cell lines.Also,there will be a discussion describing how the anti-leukemic DNA binding transcription factor,Ikaros,regulates VIP receptor expression in primary human CD4 T lymphocytes and T cell lymphoblastic cell lines (e.g.Hut-78).Lastly,future goals will be mentioned that are expected to uncover the role of how the VIP signaling axis contributes to human leukemogenesis,and to establish whether the VIP receptor signature expressed by leukemic blasts can provide therapeutic and/or diagnostic information.

  20. CMB Maximum Temperature Asymmetry Axis: Alignment with Other Cosmic Asymmetries

    CERN Document Server

    Mariano, Antonio

    2012-01-01

    We use a global pixel based estimator to identify the axis of the residual Maximum Temperature Asymmetry (MTA) (after the dipole subtraction) of the WMAP 7 year Internal Linear Combination (ILC) CMB temperature sky map. The estimator is based on considering the temperature differences between opposite pixels in the sky at various angular resolutions (4 degrees-15 degrees and selecting the axis that maximizes this difference. We consider three large scale Healpix resolutions (N_{side}=16 (3.7 degrees), N_{side}=8 (7.3 degrees) and N_{side}=4 (14.7 degrees)). We compare the direction and magnitude of this asymmetry with three other cosmic asymmetry axes (\\alpha dipole, Dark Energy Dipole and Dark Flow) and find that the four asymmetry axes are abnormally close to each other. We compare the observed MTA axis with the corresponding MTA axes of 10^4 Gaussian isotropic simulated ILC maps (based on LCDM). The fraction of simulated ILC maps that reproduces the observed magnitude of the MTA asymmetry and alignment wit...

  1. Calibration of rotary joints in multi-axis machine tools

    Science.gov (United States)

    Khan, Abdul Wahid; Liu, Fei; Chen, Wuyi

    2009-05-01

    A novel technique is developed and implemented for error quantification in a rotary joint of a multi-axis machine tool by using a calibrated double ball bar (DBB) system as a working standard. This technique greatly simplified the measurement setup requirement and accelerated the calibration of rotary joints. In addition it is highly economical by reducing the complex optics and eliminating the usage of various tooling, instrumentation and accessories. This methodology is capable of measuring the five degree of freedom (DOF) errors out of 6DOF of a rotary joint by using the calibrated DBB system and a point locating fixture. The methodology is implemented on rotary joints of a five axis CNC machine tools. Equation solvers and error modeling technique are implemented and validity of the methodology and authenticity of the results obtained are tested through simulation in UG and Matlab software. The methodology is found extremely feasible pragmatic, quite simple, efficient and easy to use for error characterization of rotary joints of multi axis machine tools.

  2. A Dual-Axis Electrostatically Driven MEMS Microgripper

    Directory of Open Access Journals (Sweden)

    Yukun Jia

    2014-11-01

    Full Text Available This paper presents the design of a new monolithic two- axis electrostatically actuated MEMS microgripper with integrated capacitive position and force sensors working at the micro-scale level. Each of the two jaws of the micro‐ gripper possesses two degrees-of-freedom (DOF and is capable of positioning in both x-and y-axes. Unlike existing works, where one gripper arm is actuated and other one is sensed, both arms of the proposed microgripper are actuated and sensed independently. A sensing scheme is constructed to provide the position and force signals in the noncontact and contact phases, respectively. By applying a 120V driving voltage, the jaw can provide 70 μm x-axis and 18 μm y-axis displacements with the force of 190 μN. By this design, the real-time position and grasping force information can be obtained in the dual sensing mode. Both analytical calculation and finite-element analysis (FEA were performed to verify the performance of the proposed design. A scaled-up prototype is designed, fabricated and tested through the experiment to verify the structure design of the microgripper.

  3. l=1 helical axis heliotron device in Kyoto university

    International Nuclear Information System (INIS)

    Helical systems are an attractive candidate for magnetic fusion reactor. Recently, there has been great progress in theoretical research of three dimensional magnetic field structures, resulting in several kinds of confinement optimization being proposed for toroidal magnetic confinement system. For example, some sophisticated ideas have appeared on stage such as quasi-helical symmetry and quasi-isodynamic system. To find experimentally which way is the best Optimisation, a new helical axis heliotron device, so called 'Heliotron J', is under construction in the Institute of Advanced Energy, Kyoto University, Japan. In this conference, the basic concept and the present status will be presented. In the conventional plane axis helical system, it was difficult to have both good particle confinement and good MHD stability simultaneously. The goal of Heliotron J project is to clarify their compatibility in the spatial axis toroidal device. The best way for Optimising the helical magnetic field configuration will be explored by investigating the plasma response to the change in the field components. The main subjects for plasma experiment are: demonstration of the existence of good magnetic flux surfaces, reduction of neoclassical transport in collisionless regime, MHD Stabilisation in high β plasma, controllability of bootstrap current, good confinement of high energy particles

  4. Finding the Orientation of the Stellar Spin Axis

    Science.gov (United States)

    Wilkinson, Tessa D.; Lesage, Anna-Lea

    2016-01-01

    The stellar position angle is defined as the projection of the stellar spin axis on the night sky, as measured from North to East. Measuring the stellar position angle gives information that can be used for stellar spin axis evolution and binary formation theories. Current methods to find this angle use imaging with long baseline interferometry for fast rotating stars. There is a lack of observational techniques to find the orientation of the stellar rotation axis for slow rotating stars, which make up the vast majority of stellar population. We developed a new method for determining the absolute stellar position angle for slow rotating stars using a spectro-astrometric analysis of high resolution long-slit spectra. We used the 2m Thueringer Landessternwarte (TLS) telescope to obtain high resolution spectra (R=60,000) with multiple slit orientations to test this method. The stellar rotation causes a tilt in the stellar lines, and the angle of this tilt depends on the stellar position angle and the orientation of the slit. We used a cross-correlation method to compare the subpixel displacements of the position of the photocenter at each slit orientation with telluric lines to obtain the tilt amplitude. We report the results of finding the position angle of the slow rotating K giant Aldebaran and fast rotating reference stars like Vega.

  5. Moving Object Detection Using Graph’s Axis Change Method

    Directory of Open Access Journals (Sweden)

    Gagandeep Kaur

    2012-03-01

    Full Text Available The detection and identify moving objects in a video sequence is very important concept. The currently available techniques for motion estimation can be broadly categorized into main classes: block matching methods and optical flow methods. But here detection of moving objects is detected by using Graph’s axis change method. Here we convert the image in to pixels and then calculate the values when the pixel change its position according to x axis and y axis. There is no problem of fixed and movable background. This paper investigates the different motion estimation algorithms used for video processing applications. Among the available motion estimation methods, the Lucas kanade Algorithm using changed axis’s method has been used in this paper for detection of moving objects in a video sequence. The algorithm produces the result of Horizontal and Vertical components velocity, u and v respectively. This velocity is measured in the form of vectors and has been used to segment the moving objects from the video sequence. The algorithm has been applied to different sets of synthetic and real video sequence.

  6. A sensitive method of determining optic axis azimuth based on laser feedback

    International Nuclear Information System (INIS)

    A sensitive method to determine the optic axis azimuth of the birefringence element is presented, which is based on laser feedback. The phase difference between the two intensities in birefringence feedback changes with the angle between the optic axis of the birefringence element and laser original polarization. The phase difference is highly sensitive to the relative position of the optic axis and the laser original polarization. This method is used to highly precisely determine the optic axis azimuth, and is able to distinguish between the fast axis and the slow axis of the birefringence element. Theoretical analysis and experimental results are both demonstrated. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  7. Variation cutting speed on the five axis milling

    Directory of Open Access Journals (Sweden)

    S. Torbaty

    2007-04-01

    Full Text Available Purpose: The aim of this research is to make a study of the effective cutting speed variation in milling with a ball end tool is studied. Then an experimental study of the effect of finishing strategies on surface texture, roughness is described. The material of a specific HB 300 pre-hardened mould steel Super Plast (SP 300.Design/methodology/approach: The methodology has consisted to dertemine cutting speed of each mode of tilt tool in five axes machining, and of proving a series of configurations and parameters combinations: cutting speed Vc, feed rate Vf, and tilt tool in multi-axis milling.Findings: This paper has investigated the effect of the tool orientation on the variation effective cutting speed, on the surface texture, while multi-axis milling. Experimental results have shown that disadvantages of three axes machining results from the existence of very low cutting speeds, even null when the tool axis is normal to the machined surface. This mode of machining generates a bad surface quality. Surfaces have a poor topography and important anisotropy. A suitable slope of the cutting tool by the means of the fifth machine tool axis, improves considerably work piece machined surface quality; Good micro-geometrical surface topography and lower surface roughness.Research limitations/implications: A possible future work would be the development of a general the phenomenal of the residual stress of the cutting on the five axis machining. The behavior is of the residual stress studies are planed in the future. Practical implications: The relationship found between the effective cutting speed and surface texture work piece has an important practical implication since it allows selecting the best cutting condition combination from the points of view both the security and the economy for the established requirements in each case. Results are of great importance in for aerospace and automotive industry.Originality/value: The paper is original since

  8. Drop Axis Ratio Distributions in Stratiform and Convective Rain

    Science.gov (United States)

    Thurai, M.; Bringi, V. N.; Petersen, W. A.; Schultz, C.

    2010-01-01

    A fully calibrated low profile 2D video disdrometer (2DVD) has been recording many different rainfall events in Northern Alabama (USA) since June 2007. An earlier publication reported drop shapes and axis ratio distributions determined for some of the events. For one of the cases examined, a noticeable shift in the 3.5 - 3.75 mm drop axis ratio distribution was noted. In this paper, we extend the earlier work by separating the 2DVD measurements into stratiform and convective rain. The separation is made possible by using the minute-by-minute drop size distribution (DSD) measured by the 2DVD. The 1-minute DSDs are fitted to a gamma distribution, and using a simple indexing technique which involves two of the fitted parameters, periods of convective and stratiform rain are separated for a given event. The output of the DSD indexing technique is qualitatively confirmed by comparing with simultaneous time series observations from a co-located UHF profiler which continuously records height profiles of reflectivity, Doppler mean and spectral width, all of which enable the identification of bright-band periods and, furthermore, periods of moderate and deep convection. Excellent consistency is found between the output of the DSD-based separation method and the profiler observations. Next, we utilize the output of DSD index-based separation method to flag the periods of severe convection for a given event. Drop axis ratios during the flagged periods are derived and compared with those during stratiform rain periods. Five cases have been considered. Axis ratio distributions do not show appreciable differences between stratiform and convective periods for four of the cases. The fifth case (the same case as reported earlier) shows a shift in the 3.5 - 3.75 mm drop axis ratios during a prolonged period of convection. The contoured shapes for these drops determined from the 2DVD camera data indicate the possibility of non-axisymmetric oscillations, compared with the contoured

  9. FAMILY HISTORY STUDY OF THE FAMILIAL COAGGREGATION OF BORDERLINE PERSONALITY DISORDER WITH AXIS I AND NON-BORDERLINE DRAMATIC CLUSTER AXIS II DISORDERS

    OpenAIRE

    Zanarini, Mary C.; Barison, Leah K.; Frankenburg, Frances R.; Reich, D. Bradford; Hudson, James I

    2009-01-01

    The purpose of this study was to assess the familial coaggregation of borderline personality disorder (BPD) with a full array of axis I disorders and four axis II disorders (antisocial personality disorder, histrionic personality disorder, narcissistic personality disorder, and sadistic personality disorder) in the first-degree relatives of borderline probands and axis II comparison subjects. Four hundred and forty-five inpatients were interviewed about familial psychopathology using the Revi...

  10. Automated segmentation of the human hippocampus along its longitudinal axis.

    Science.gov (United States)

    Lerma-Usabiaga, Garikoitz; Iglesias, Juan Eugenio; Insausti, Ricardo; Greve, Douglas N; Paz-Alonso, Pedro M

    2016-09-01

    The human hippocampal formation is a crucial brain structure for memory and cognitive function that is closely related to other subcortical and cortical brain regions. Recent neuroimaging studies have revealed differences along the hippocampal longitudinal axis in terms of structure, connectivity, and function, stressing the importance of improving the reliability of the available segmentation methods that are typically used to divide the hippocampus into its anterior and posterior parts. However, current segmentation conventions present two main sources of variability related to manual operations intended to correct in-scanner head position across subjects and the selection of dividing planes along the longitudinal axis. Here, our aim was twofold: (1) to characterize inter- and intra-rater variability associated with these manual operations and compare manual (landmark based) and automatic (percentage based) hippocampal anterior-posterior segmentation procedures; and (2) to propose and test automated rotation methods based on approximating the hippocampal longitudinal axis to a straight line (estimated with principal component analysis, PCA) or a quadratic Bézier curve (fitted with numerical methods); as well as an automated anterior-posterior hippocampal segmentation procedure based on the percentage-based method. Our results reveal that automated rotation and segmentation procedures, used in combination or independently, minimize inconsistencies generated by the accumulation of manual operations while providing higher statistical power to detect well-known effects. A Matlab-based implementation of these procedures is made publicly available to the research community. Hum Brain Mapp 37:3353-3367, 2016. © 2016 Wiley Periodicals, Inc. PMID:27159325

  11. Gaussian tunneling model of c-axis twist Josephson junctions

    International Nuclear Information System (INIS)

    We calculate the critical current density JcJ((varphi)0) for Josephson tunneling between identical high-temperature superconductors twisted an angle (varphi)0 about the c axis. Regardless of the shape of the two-dimensional Fermi surface and for very general tunneling matrix elements, an order parameter (OP) with general d-wave symmetry leads to JcJ(π/4)=0. This general result is inconsistent with the data of Li et al. [Phys. Rev. Lett. 83, 4160 (1999)] on Bi2Sr2CaCu2O8+δ (Bi2212), which showed JcJ to be independent of (varphi)0. If the momentum parallel to the barrier is conserved in the tunneling process, JcJ should vary substantially with the twist angle (varphi)0 when the tight-binding Fermi surface appropriate for Bi2212 is taken into account, even if the OP is completely isotropic. We quantify the degree of momentum nonconservation necessary to render JcJ((varphi)0) constant within experimental error for a variety of pair states by interpolating between the coherent and incoherent limits using five specific models to describe the momentum dependence of the tunneling matrix element squared. From the data of Li et al., we conclude that the c-axis tunneling in Bi2212 must be very nearly incoherent, and that the OP must have a nonvanishing Fermi-surface average for Tc. We further show that the apparent conventional sum-rule violation observed by Basov et al. [Science 283, 49 (1999)] can be consistent with such strongly incoherent c-axis tunneling.

  12. Optical diffraction tomography: accuracy of an off-axis reconstruction

    Science.gov (United States)

    Kostencka, Julianna; Kozacki, Tomasz

    2014-05-01

    Optical diffraction tomography is an increasingly popular method that allows for reconstruction of three-dimensional refractive index distribution of semi-transparent samples using multiple measurements of an optical field transmitted through the sample for various illumination directions. The process of assembly of the angular measurements is usually performed with one of two methods: filtered backprojection (FBPJ) or filtered backpropagation (FBPP) tomographic reconstruction algorithm. The former approach, although conceptually very simple, provides an accurate reconstruction for the object regions located close to the plane of focus. However, since FBPJ ignores diffraction, its use for spatially extended structures is arguable. According to the theory of scattering, more precise restoration of a 3D structure shall be achieved with the FBPP algorithm, which unlike the former approach incorporates diffraction. It is believed that with this method one is allowed to obtain a high accuracy reconstruction in a large measurement volume exceeding depth of focus of an imaging system. However, some studies have suggested that a considerable improvement of the FBPP results can be achieved with prior propagation of the transmitted fields back to the centre of the object. This, supposedly, enables reduction of errors due to approximated diffraction formulas used in FBPP. In our view this finding casts doubt on quality of the FBPP reconstruction in the regions far from the rotation axis. The objective of this paper is to investigate limitation of the FBPP algorithm in terms of an off-axis reconstruction and compare its performance with the FBPJ approach. Moreover, in this work we propose some modifications to the FBPP algorithm that allow for more precise restoration of a sample structure in off-axis locations. The research is based on extensive numerical simulations supported with wave-propagation method.

  13. Fracture surface characteristics of off-axis composites

    Science.gov (United States)

    Sinclair, J. H.; Chamis, C. C.

    1977-01-01

    The fracture surface characteristics of off-axis high-modulus graphite-fiber/epoxy composite specimens were studied using a scanning electron microscope (SEM). The specimens were subjected to tensile loading at various angles (0-90 deg) to the fiber direction. SEM photomicrographs of the fractured surfaces revealed three different load angle regions with distinct fracture characteristics. Based on these revelations, criteria were established which can be used to characterize fracture surfaces with respect to a predominant 'single-stress' fracture mode.

  14. A Generator Perspective on Vertical Axis Wind Turbines

    OpenAIRE

    Bülow, Fredrik

    2013-01-01

    The wind energy conversion system considered in this thesis is based on a vertical axis wind turbine with a cable wound direct drive PM generator. Diode rectifiers are used to connect several such units to a single DC-bus and a single inverter controls the power flow from the DC-bus to a utility grid. This work considers the described system from a generator perspective i.e. the turbine is primarily seen as a torque and the inverter is seen as a controlled load. A 12 kW VAWT prototype with a ...

  15. Error Model and Accuracy Calibration of 5-Axis Machine Tool

    Directory of Open Access Journals (Sweden)

    Fangyu Pan

    2013-08-01

    Full Text Available To improve the machining precision and reduce the geometric errors for 5-axis machinetool, error model and calibration are presented in this paper. Error model is realized by the theory of multi-body system and characteristic matrixes, which can establish the relationship between the cutting tool and the workpiece in theory. The accuracy calibration was difficult to achieve, but by a laser approach-laser interferometer and laser tracker, the errors can be displayed accurately which is benefit for later compensation.

  16. Role of the lysophosphatidylinositol/GPR55 axis in cancer.

    Science.gov (United States)

    Falasca, Marco; Ferro, Riccardo

    2016-01-01

    Lysophosphatidylinositol (LPI) is a well-known bioactive lipid that is able to activate signalling cascades relevant to cell proliferation, migration, survival and tumourigenesis. It is well-established that the G protein-coupled receptor 55 (GPR55) is the specific receptor for LPI. Several investigations have demonstrated that the signalling pathways activated by LPI through its receptor GPR55 play a pivotal role in different cancer type. This review focuses on the role of the LPI/GPR55 axis, in particular with regards to its pharmacological potential therapeutic exploitation. PMID:26588872

  17. Resonance acceptor states in single-axis deformed semiconductors

    CERN Document Server

    Odnoblyudov, M A; Yassievich, I N

    2002-01-01

    The new approach is proposed to the resonance state parameters, making it possible to determine also the probabilities of the resonance scattering and capture probability into the resonance state. It is based on the application of the Fano configuration interaction method. Two different Hamiltonians of the zero approximation are applied for the continuum states and local priming state. The wave functions are plotted by the method, accepted in the common scattering theory. The detailed consideration and concrete calculations for the acceptor resonance states in the single-axis deformed germanium by the pressure along the axes [001] and [111] are carried out

  18. Tilted axis cranking covariant density functional theory and its applications

    International Nuclear Information System (INIS)

    Recent progress on tilted axis cranking covariant density functional theory (CDFT) and its applications to nuclear magnetic and antimagnetic rotation are briefly presented. In particular, the magnetic rotation band in 198Pb and the antimagnetic rotational band in 105Cd are discussed. Without any additional parameter, the experimental relation between angular momentum and rotational frequency for the magnetic rotation band in 198Pb as well as the data of B(E2) values for the antimagnetic rotation band in 105Cd are reproduced very well

  19. The diet-microbiota-metabolite axis regulates the host physiology.

    Science.gov (United States)

    Yamada, Takahiro; Takahashi, Daisuke; Hase, Koji

    2016-07-01

    The intestinal microbiota has been implicated in a wide range of diseases, including inflammatory bowel disease, obesity and cancer. Food ingredients are considered a major determinant of gut microbial composition, as exemplified by high-fat diet-induced dysbiosis that can affect host physiology. Accumulating studies show that microbial metabolites are key regulators of the intestinal epithelial barrier and gut immunity. In particular, short-chain fatty acids produced by bacterial fermentation of indigestible polysaccharides have profound impacts on host physiology beyond the gut. In this review, we describe the influences of the diet-microbiota-metabolite axis on host physiology, and especially on the immune and metabolic systems. PMID:26970281

  20. On the off-axis tensile test for unidirectional composites

    Science.gov (United States)

    Nemeth, M. P.; Herakovich, C. T.; Post, D.

    1982-01-01

    The off axis tensile test was examined experimentally to obtain actual displacement fields over the surface of graphite polyimide coupon specimens. The experimental results were compared with approximate analytical solutions and generated finite element results. An optical method of high sensitivity moire interferometry was used to determine the actual displacements to high precision. The approximate analytical solution and the finite element results compare very favorably with the measured centerline displacements in the test section, and the finite element displacement fields provide excellent agreement with the moire displacements throughout the specimen. A 15 degree fiber orientation and coupon aspect ratios of 5 and 15 are presented.

  1. Asteroid Shape and Spin Axis Modeling Via Light Curve Inversion

    Science.gov (United States)

    Friz, Paul; Gokhale, V.

    2013-01-01

    We present light curves and shape and spin axis models for the five asteroids: 291 Alice, 281 Lucretia, 321 Florentina, 714 Ulula, and 3169 Ostro. These models were obtained using data taken from the Truman Observatory, the Asteroid Photometric Catalogue, and the Minor Planet Center. Knowledge of individual asteroids shapes and spin axes is vital to understanding the solar system. However, currently only 213 out of the 500,000 asteroids with known orbits have been modeled. By taking many light curves of asteroids over several apparitions it is possible to determine their shapes and spin axes by a process known as light curve inversion.

  2. The interleukin-20 receptor axis in early rheumatoid arthritis

    DEFF Research Database (Denmark)

    Kragstrup, Tue Wenzel; Greisen, Stinne Ravn; Nielsen, Morten Aagaard;

    2016-01-01

    BACKGROUND: Rheumatoid arthritis (RA) is often characterized by the presence of rheumatoid factor, anti-citrullinated protein antibodies, and bone erosions. Current therapies can compromise immunity, leading to risk of infection. The interleukin-20 receptor (IL-20R) axis comprising IL-19, IL-20...... RA synovial fluid compared with monocytes from both RA and healthy control peripheral blood. The plasma concentrations of IL-20 and IL-24 were increased in rheumatoid factor and anti-citrullinated protein antibody positive compared with negative early RA patients (all P < 0.0001). Immune complexes...

  3. Embedded synaptic feedback in the neuroendocrine stress axis.

    Science.gov (United States)

    Wamsteeker Cusulin, J I; Bains, J S

    2015-06-01

    Neural regulation of blood glucocorticoid levels is critical for defence of homeostasis during physiological or psychoemotional challenges. In mammals, this function is carried out by the neuroendocrine stress axis, coordinated by parvocellular neuroendocrine cells (PNCs) of the paraventricular hypothalamic nucleus. Feedback regulation of PNCs by glucocorticoids provides complex experience-dependent shaping of neuroendocrine responses. We review recent evidence for metaplastic actions of glucocorticoids as 'circuit breakers' at synapses directly regulating PNC excitability and explore how such mechanisms may serve as substrates for stress adaptation. PMID:25612538

  4. Fabrication of Dual-Axis Solar Tracking Controller Project

    OpenAIRE

    Nader Barsoum

    2011-01-01

    The recent decades have seen the increase in demand for reliable and clean form of electricity derived from renewable energy sources. One such example is solar power. The challenge remains to maximize the capture of the rays from the sun for conversion into electricity. This paper presents fabrication and installation of a solar panel mount with a dual-axis solar tracking controller. This is done so that rays from the sun fall perpendicularly unto the solar panels to maximize the capture of t...

  5. Microwave metal disk antenna with axis-symmetric excitation

    OpenAIRE

    I. Ivanchenko; A. Korolev; Karelin, S.; Laz'ko, E.; Lukyanova, N.; N. Popenko

    2003-01-01

    The paper presents a microwave metal disk antenna with axis-symmetric excitation operating in the TM010 mode. Experimental investigations of the input characteristics of the antenna, and of the near-fields and the radiation pattern, have been performed. It was shown that the antenna forms a conical radiation pattern, oriented 36° to the zenith, and has a bandwidth of 18% that can be evaluated as a record for antennas of this kind. The antenna also has a level of side radiation as well as a cr...

  6. Low Reynolds number airfoils for small horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Giguere, Philippe; Selig, Michael S. [University of Illinois at Urbana-Chanpaign (United States). Dept. of Aeronautical and Astronautical Engineering

    1997-12-31

    To facilitate the airfoil selection process for small horizontal-axis wind turbines, an extensive database of low Reynolds number airfoils has been generated. The database, which consists of lift and drag data, was obtained from experiments conducted in the same wind tunnel testing facility. Experiments with simulated leading-edge roughness were also performed to model the effect of blade erosion and the accumulation of roughness elements, such as insect debris, on airfoil performance. Based on the lift curves and drag polars, guidelines that should be useful in selecting appropriate airfoils for particular blade designs are given. Some of these guidelines are also applicable to larger HAWTs. (author)

  7. Resonances and Aerodynamic Damping of a Vertical Axis Wind Turbine

    OpenAIRE

    Ottermo, Fredric; Bernhoff, Hans

    2012-01-01

    The dynamics of a straight-bladed vertical axis wind turbine is investigated with respect to oscillations due to the elasticity of struts and shaft connecting to the hub. In particular, for the three-bladed turbine, a concept is proposed for dimensioning the turbine to maximize the size of the resonance free rpm range for operation. The effect of aerodynamic damping on the struts is also considered. The damping of these types of oscillations for a typical turbine is found to be good.

  8. IL-33/ST2 axis in inflammation and immunopathology.

    Science.gov (United States)

    Milovanovic, Marija; Volarevic, Vladislav; Radosavljevic, Gordana; Jovanovic, Ivan; Pejnovic, Nada; Arsenijevic, Nebojsa; Lukic, Miodrag L

    2012-04-01

    Interleukin-33 (IL-33), a member of the IL-1 family of cytokines, binds to its plasma membrane receptor, heterodimeric complex consisted of membrane-bound ST2L and IL-1R accessory protein, inducing NFkB and MAPK activation. IL-33 exists as a nuclear precursor and may act as an alarmin, when it is released after cell damage or as negative regulator of NFκB gene transcription, when acts in an intracrine manner. ST2L is expressed on several immune cells: Th2 lymphocytes, NK, NKT and mast cells and on cells of myeloid lineage: monocytes, dendritic cells and granulocytes. IL-33/ST2 axis can promote both Th1 and Th2 immune responses depending on the type of activated cell and microenvironment and cytokine network in damaged tissue. We previously described and discuss here the important role of IL-33/ST2 axis in experimental models of type 1 diabetes, experimental autoimmune encephalomyelitis, fulminant hepatitis and breast cancer. We found that ST2 deletion enhance the development of T cell-mediated autoimmune disorders, EAE and diabetes mellitus type I. Disease development was accompanied by dominantly Th1/Th17 immune response but also higher IL-33 production, which suggest that IL-33 in receptor independent manner could promote the development of inflammatory autoreactive T cells. IL-33/ST2 axis has protective role in Con A hepatitis. ST2-deficient mice had more severe hepatitis with higher influx of inflammatory cells in liver and dominant Th1/Th17 systemic response. Pretreatment of mice with IL-33 prevented Con A-induced liver damage through prevention of apoptosis of hepatocytes and Th2 amplification. Deletion of IL-33/ST2 axis enhances cytotoxicity of NK cells, production of IFN-γ in these cells and systemic production of IFN-γ, IL-17 and TNF-α, which leads to attenuated tumor growth. IL-33 treatment of tumor-bearing mice suppresses activity of NK cells, dendritic cell maturation and enhances alternative activation of macrophages. In conclusion, we observed

  9. A novel multi-axis force sensor for microrobotics applications

    International Nuclear Information System (INIS)

    High performance force sensors often encounter the conflicting requirements of fine sensitivity and wide bandwidth. While there is an intrinsic tradeoff between these two metrics that cannot be physically avoided for any force transducer, through proper optimization the product of these two can be maximized. Similarly, the requirements of multiple sensing axes and overall compactness are also often at odds. This paper describes a novel design, simple method of fabrication, and thorough analysis of a high performance two-axis force sensor. We conclude with an example application: measuring the lift and drag forces from a flapping-wing robotic insect

  10. The cathode test stand for the DARHT second-axis

    International Nuclear Information System (INIS)

    The injector for the DARHT second-axis injector will use an 8-in. thermionic dispenser cathode. Because the cathode is relatively large and requires a large amount of heat (5 kW) there are certain engineering issues that need to be addressed, before the DARHT injector reaches the final design stage. The Cathode Test Stand (CTS) will be used to address those concerns. The CTS is a new facility, presently under construction. The CTS will consist of a high-voltage pulse modulator, a high-vacuum diode test-chamber, and a short beam-transport section with diagnostics. This paper discusses the status of the project

  11. Experimental characterization of vertical-axis wind turbine noise.

    Science.gov (United States)

    Pearson, C E; Graham, W R

    2015-01-01

    Vertical-axis wind turbines are wind-energy generators suitable for use in urban environments. Their associated noise thus needs to be characterized and understood. As a first step, this work investigates the relative importance of harmonic and broadband contributions via model-scale wind-tunnel experiments. Cross-spectra from a pair of flush-mounted wall microphones exhibit both components, but further analysis shows that the broadband dominates at frequencies corresponding to the audible range in full-scale operation. This observation has detrimental implications for noise-prediction reliability and hence also for acoustic design optimization. PMID:25618090

  12. Wake-Assisted Windmill System with Parallel Vertical-Axis

    OpenAIRE

    YAMAGISHI, Masaki; Sato, Daisuke; MIYASHITA, Jun; Nozaki, Kentaro; 山岸, 真幸; 佐藤, 大資; 宮下, 准; 野崎, 健太郎

    2003-01-01

    For the improvement of the performance of drag-type windmills with vertical-axis, the experimental study proposed the windmill system using the wake behind a bluff body. The model windmill has two Savonius rotors that were set in parallel behind the circular cylinder. Through the wind tunnel experiment the revolution of the rotor of the windmill system was compared with that of the single rotor. The revolution of the windmill system was found higher than that of the single rotor. Also the opt...

  13. Axis-1 diode simulations I: standard 2-inch cathode

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl [Los Alamos National Laboratory

    2011-01-11

    The standard configuration of the DARHT Axis-I diode features a 5.08-cm diameter velvet emitter mounted in the flat surface of the cathode shroud. The surface of the velvet is slightly recessed {approx}2.5 mm. This configuration produces a 1.75 kA beam when a 3.8-MV pulse is applied to the anode-cathode (AK) gap. This note addresses some of the physics of this diode through the use of finite-element simulations.

  14. Design of h-Darrieus vertical axis wind turbine

    OpenAIRE

    Parra Teresa; Vega Carmen; Gallegos A.; Uzarraga N. C.; Castro F.

    2015-01-01

    Numerical simulation is used to predict the performance of a Vertical Axis Wind Turbine (VAWT) H-Darrieus. The rotor consists of three straight blades with shape of aerofoil of the NACA family attached to a rotating vertical shaft. The influence of the solidity is tested to get design tendencies. The mesh has two fluid volumes: one sliding mesh for the rotor where the rotation velocity is established while the other is the environment of the rotor. Bearing in mind the overall flow is characte...

  15. Wake Development of a Model Vertical Axis Wind Turbine

    Science.gov (United States)

    Kadum, Hawwa; Friedman, Sasha; Camp, Elizabeth; Cal, Rau'l.

    2015-11-01

    At the Portland State University wind tunnel facility, an experiment is conducted to observe the downstream development of the wake past a model vertical axis wind turbine (VAWT). The flow domain is composed of streamwise-spanwise planes at mid-height of the VAWT rotor and data is obtained via particle image velocimetry (PIV). The flow field is assessed by analyzing contours of mean velocities and the full Reynolds stress tensor. Furthermore, profiles of the aforementioned quantities and flow parameters are discussed in the context of downstream evolution/flow development.

  16. Electric power from vertical-axis wind turbines

    Science.gov (United States)

    Touryan, K. J.; Strickland, J. H.; Berg, D. E.

    1987-12-01

    Significant advancements have occurred in vertical axis wind turbine (VAWT) technology for electrical power generation over the last decade; in particular, well-proven aerodynamic and structural analysis codes have been developed for Darrieus-principle wind turbines. Machines of this type have been built by at least three companies, and about 550 units of various designs are currently in service in California wind farms. Attention is presently given to the aerodynamic characteristics, structural dynamics, systems engineering, and energy market-penetration aspects of VAWTs.

  17. Large Eddy Simulation of Vertical Axis Wind Turbine Wakes

    OpenAIRE

    Sina Shamsoddin; Fernando Porté-Agel

    2014-01-01

    In this study, large eddy simulation (LES) is combined with a turbine model to investigate the wake behind a vertical-axis wind turbine (VAWT) in a three-dimensional turbulent flow. Two methods are used to model the subgrid-scale (SGS) stresses: (a) the Smagorinsky model; and (b) the modulated gradient model. To parameterize the effects of the VAWT on the flow, two VAWT models are developed: (a) the actuator swept-surface model (ASSM), in which the time-averaged turbine-induced forces are dis...

  18. A 34-meter VAWT (Vertical Axis Wind Turbine) point design

    Science.gov (United States)

    Ashwill, T. D.; Berg, D. E.; Dodd, H. M.; Rumsey, M. A.; Sutherland, H. J.; Veers, P. S.

    The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s.

  19. Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

    Science.gov (United States)

    Graf, Eveline S.; Wright, Ian C.; Stefanyshyn, Darren J.

    2012-01-01

    The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location. PMID:22666303

  20. Research on identifying the dynamic error model of strapdown gyro on 3-axis turntable

    Institute of Scientific and Technical Information of China (English)

    WANG Hai; REN Shun-qing; WANG Chang-hong

    2005-01-01

    The dynamic errors of gyros are the important error sources of a strapdown inertial navigation system.In order to identify the dynamic error model coefficients accurately, the static erTor model coefficients which lay a foundation for compensating while identifying the dynamic error model are identified in the gravity acceleration fields by using angular position function of the three-axis turntable. The angular acceleration and angular velocity are excited on the input, output and spin axis of the gyros when the outer axis and the middle axis of a threeaxis turntable are in the uniform angular velocity state simultaneously, while the inner axis of the turntable is in different static angular positions. 8 groups of data are sampled when the inner axis is in 8 different angular positions. These data are the function of the middle axis positions and the inner axis positions. For these data, harmonic analysis method is applied two times versus the middle axis positions and inner axis positions respectively so that the dynamic error model coefficients are finally identified through the least square method. In the meantime the optimal angular velocity of the outer axis and the middle axis are selected by computing the determination value of the information matrix.

  1. Modeling the brain-pituitary-gonad axis in salmon

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jonghan; Hayton, William L.; Schultz, Irv R.

    2006-08-24

    To better understand the complexity of the brain-pituitary-gonad axis (BPG) in fish, we developed a biologically based pharmacodynamic model capable of accurately predicting the normal functioning of the BPG axis in salmon. This first-generation model consisted of a set of 13 equations whose formulation was guided by published values for plasma concentrations of pituitary- (FSH, LH) and ovary- (estradiol, 17a,20b-dihydroxy-4-pregnene-3-one) derived hormones measured in Coho salmon over an annual spawning period. In addition, the model incorporated pertinent features of previously published mammalian models and indirect response pharmacodynamic models. Model-based equations include a description of gonadotropin releasing hormone (GnRH) synthesis and release from the hypothalamus, which is controlled by environmental variables such as photoperiod and water temperature. GnRH stimulated the biosynthesis of mRNA for FSH and LH, which were also influenced by estradiol concentration in plasma. The level of estradiol in the plasma was regulated by the oocytes, which moved along a maturation progression. Estradiol was synthesized at a basal rate and as oocytes matured, stimulation of its biosynthesis occurred. The BPG model can be integrated with toxico-genomic, -proteomic data, allowing linkage between molecular based biomarkers and reproduction in fish.

  2. Stable three-axis nuclear-spin gyroscope in diamond

    Science.gov (United States)

    Ajoy, Ashok; Cappellaro, Paola

    2012-12-01

    Gyroscopes find wide applications in everyday life from navigation and inertial sensing to rotation sensors in hand-held devices and automobiles. Current devices, based on either atomic or solid-state systems, impose a choice between long-time stability and high sensitivity in a miniaturized system. Here, we introduce a quantum sensor that overcomes these limitations by providing a sensitive and stable three-axis gyroscope in the solid state. We achieve high sensitivity by exploiting the long coherence time of the 14N nuclear spin associated with the nitrogen-vacancy center in diamond, combined with the efficient polarization and measurement of its electronic spin. Although the gyroscope is based on a simple Ramsey interferometry scheme, we use coherent control of the quantum sensor to improve its coherence time and robustness against long-time drifts. Such a sensor can achieve a sensitivity of η˜0.5(mdegs-1)/Hzmm3 while offering enhanced stability in a small footprint. In addition, we exploit the four axes of delocalization of the nitrogen-vacancy center to measure not only the rate of rotation, but also its direction, thus obtaining a compact three-axis gyroscope.

  3. Related Axis: The Extension to XPath Towards Effective XML Search

    Institute of Scientific and Technical Information of China (English)

    Jun-Feng Zhou; Tok Wang Ling; Zhi-Feng Bao; Xiao-Feng Meng

    2012-01-01

    We investigate the limitations of existing XML search methods and propose a new semantics,related relationship,to effectively capture meaningful relationships of data elements from XML data in the absence of structural constraints.Then we make an extension to XPath by introducing a new axis,related axis,to specify the related relationship between query nodes so as to enhance the flexibility of XPath.We propose to reduce the cost of computing the related relationship by a new schema summary that summarizes the related relationship from the original schema without any loss.Based on this schema summary,we introduce two indices to improve the performance of query processing.Our algorithm shows that the evaluation of most queries can be equivalently transformed into just a few selection and value join operations,thus avoids the costly structural join operations.The experimental results show that our method is effective and efficient in terms of comparing the effectiveness of the related relationship with existing keyword search semantics and comparing the efficiency of our evaluation methods with existing query engines.

  4. On the spin-axis dynamics of a Moonless Earth

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gongjie; Batygin, Konstantin, E-mail: gli@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, The Institute for Theory and Computation, 60 Garden Street, Cambridge, MA 02138 (United States)

    2014-07-20

    The variation of a planet's obliquity is influenced by the existence of satellites with a high mass ratio. For instance, Earth's obliquity is stabilized by the Moon and would undergo chaotic variations in the Moon's absence. In turn, such variations can lead to large-scale changes in the atmospheric circulation, rendering spin-axis dynamics a central issue for understanding climate. The relevant quantity for dynamically forced climate change is the rate of chaotic diffusion. Accordingly, here we re-examine the spin-axis evolution of a Moonless Earth within the context of a simplified perturbative framework. We present analytical estimates of the characteristic Lyapunov coefficient as well as the chaotic diffusion rate and demonstrate that even in absence of the Moon, the stochastic change in Earth's obliquity is sufficiently slow to not preclude long-term habitability. Our calculations are consistent with published numerical experiments and illustrate the putative system's underlying dynamical structure in a simple and intuitive manner.

  5. Rotation axis demultiplexer enabling simultaneous computed tomography of multiple samples.

    Science.gov (United States)

    Trtik, Pavel; Geiger, Fabian; Hovind, Jan; Lang, Udo; Lehmann, Eberhard; Vontobel, Peter; Peetermans, Steven

    2016-01-01

    This paper describes a device that allows for simultaneous tomographic imaging of samples on three independent rotational axes. This rotation axis demultiplexer (POLYTOM) is equipped with anti-backlash gears and placed on a standard sample rotation stage thus allowing for the transformation of the input rotation axis onto two additional parallel vertical axes. Consequently, three times the number of samples can be investigated within a given time period, thereby reducing the acquisition time of multiple sample tomographic investigations by a factor of three. The results of our pilot experiments using neutron tomographic imaging are presented. We foresee that the device will be of particular use for tomographic imaging of elongated samples at low-flux (e.g. neutron) sources; however, its use for the more widespread types of imaging techniques (e.g. X-rays) is not ruled out. The highlights of this new device for the purpose of the (neutron) computed tomography are: •Anti-backlash transformation of the input rotation onto two additional rotational axes.•Reduction of the acquisition time of the multiple sample tomographic investigations by a factor of three.•Low-cost. PMID:27158597

  6. PRIGo: a new multi-axis goniometer for macromolecular crystallography

    International Nuclear Information System (INIS)

    The design and performance of the new multi-axis goniometer PRIGo developed at the Swiss Light Source at Paul Scherrer Institute is described. The Parallel Robotics Inspired Goniometer (PRIGo) is a novel compact and high-precision goniometer providing an alternative to (mini-)kappa, traditional three-circle goniometers and Eulerian cradles used for sample reorientation in macromolecular crystallography. Based on a combination of serial and parallel kinematics, PRIGo emulates an arc. It is mounted on an air-bearing stage for rotation around ω and consists of four linear positioners working synchronously to achieve x, y, z translations and χ rotation (0–90°), followed by a ϕ stage (0–360°) for rotation around the sample holder axis. Owing to the use of piezo linear positioners and active correction, PRIGo features spheres of confusion of <1 µm, <7 µm and <10 µm for ω, χ and ϕ, respectively, and is therefore very well suited for micro-crystallography. PRIGo enables optimal strategies for both native and experimental phasing crystallographic data collection. Herein, PRIGo hardware and software, its calibration, as well as applications in macromolecular crystallography are described

  7. Miniature image guided three-axis scanning and positioning system

    Science.gov (United States)

    Avirovik, Dragan; Dave, Digant; Priya, Shashank

    2012-04-01

    We have developed a high precision three axes scanning and positioning system for integration with Multifunctional Image Guided Surgical (MIGS) Platform. The stage integrates three main components: an optical coherence tomography (OCT) probe, laser scalpel and suction cup. The requirements for this stage were to provide scanning area of 400mm2, resolution of less than 10 microns and scanning velocity in the range of 10 - 40 mm/s. The stage was modeled using computer aided design software NX Unigraphics. In addition to the parameters mentioned above, additional boundary conditions for the stage were set as low volume and modularity. Optimized stage model was fabricated by using rapid prototyping technique that integrates low cost stepper motors, threaded rod drive train and a stepper motor controller. The EZ4axis stepper motor controller was able to provide 1/8th microstep resolution control over the motors, which met the criterion desired for the MIGS platform. Integration of computer controlled three-axis stage with MIGS platform provides the opportunity for conducting intricate surgical procedures using remote control or joystick. The device is image guided using the OCT probe and it is able to pin point any location requiring a laser scalpel incision. Due to the scanning capabilities, a high quality threedimensional image of the tissue topography is obtained which allows the surgeon to make a confident decision of where to apply the laser scalpel and make an incision.

  8. Microcontroller based two axis microtron beam extraction system

    International Nuclear Information System (INIS)

    Microtron is an electron accelerator which is used to accelerate the electron beam. The Microtron consists of electro magnet with two poles separated by yoke for completion of path for magnetic flux lines. A compact Microtron capable of accelerating electrons up to 12 MeV has been developed in RRCAT. The beam from the Microtron has to be extracted from various orbits depending upon the user requirement (X-Y stage is built with an accuracy of 100 μm). This paper describes the design and development of microcontroller based two axis beam extraction system for Microtron, with a resolution of 50 μm to position the extraction tube with respect to selected orbit. Two axis motion controller is developed using current controlled micro-stepping driver mechanism, which uses Bipolar Chopper Drive for driving stepper motors. Each phase has 2A continuous driving capability. The system is provided with user selectable controls like speed, steps, direction, and mode. This system is provided with RS-232 interface, to accept commands from PC. This system also has local keyboard and LCD interface to use in Stand-alone mode (local Mode). (author)

  9. Harnessing Tidal Energy Using Vertical Axis Tidal Turbine

    Directory of Open Access Journals (Sweden)

    Syed Shah Khalid

    2013-01-01

    Full Text Available An overview of the current design practices in the field of Renewable Energy (RE is presented; also paper delineates the background to the development of unique and novel techniques for power generation using the kinetic energy of tidal streams and other marine currents. Also this study focuses only on vertical axis tidal turbine. Tidal stream devices have been developed as an alternative method of extracting the energy from the tides. This form of tidal power technology poses less threat to the environment and does not face the same limiting factors associated with tidal barrage schemes, therefore making it a more feasible method of electricity production. Large companies are taking interest in this new source of power. There is a rush to research and work with this new energy source. Marine scientists are looking into how much these will affect the environment, while engineers are developing turbines that are harmless for the environment. In addition, the progression of technological advancements tracing several decades of R & D efforts on vertical axis turbines is highlighted.

  10. Three-axis positional drift correction in scanning probe microscopy

    Science.gov (United States)

    Follin, Nathan D.; Musalo, Christopher J.; Trawick, Matthew L.

    2011-03-01

    Positional drift in scanning probe microscopy can cause image distortion and metrological errors of tens of nanometers or more. It can arise from thermal drift, due to thermal expansion of materials in the sample and microscope while scanning, or from piezo creep, particularly along the z axis. We present a technique for correcting positional drift errors in all three axes. Our method works by comparing each scanned topographical image to a second, partial scan, taken immediately afterwards, on which the fast and slow scan axes have been reversed. We model the positional distortion as a low-order polynomial function in three dimensions, searching for the set of correctional coefficients that minimizes the difference between the two scans. Using this technique we have successfully reduced positional errors from 50 nm to 0.5 nm in the z axis, and from 40 nm to 2 nm (about half of a single pixel) in the xy plane. Supported by an award from Research Corporation for Science Advancement, and by the American Chemical Society Petroleum Research Fund through Grant number 46380-GB7.

  11. Thermal performance of microinverters on dual-axis trackers

    Science.gov (United States)

    Hossain, Mohammad A.; Peshek, Timothy J.; Xu, Yifan; Ji, Liang; Sun, Jiayang; Abramson, Alexis; French, Roger H.

    2014-10-01

    Time-series insolation, environmental, thermal and power data were analyzed in a statistical analytical approach to identify the thermal performance of microinverters on dual-axis trackers under real-world operating conditions. This study analyzed 24 microinverters connected to 8 different brands of photovoltaic (PV) modules from July through October 2013 at the Solar Durability and Lifetime Extension (SDLE) SunFarm at Case Western Reserve University. Exploratory data analysis shows that the microinverter's temperature is strongly correlated with ambient temperature and PV module temperature, and moderately correlated with irradiance and AC power. Noontime data analysis reveals the variations of thermal behavior across different brands of PV module. Hierarchical clustering using the Euclidean distance measure principle was applied to noontime microinverter temperature data to group the similarly behaved microinverters. A multiple regression predictive model has been developed based on ambient temperature, PV module temperature, irradiance and AC power data to predict the microinverters temperature connected with different brands PV modules on dual-axis trackers.

  12. Searching for Cosmological Preferred Axis using cosmographic approach

    CERN Document Server

    Salehi, Amin

    2016-01-01

    Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. This hints a cosmological privileged axis in our anisotropic expanding universe. This paper proceeds a modified redshift in anisotropic cosmological model as $ 1+\\tilde{z}(t,\\hat{\\textbf{p}})=\\frac{a(t_{0)}}{a(t)}(1-A(\\hat{\\textbf{n}}.\\hat{\\textbf{p}}))$ (where $A$ is the magnitude of anisotropy ,$\\hat{\\textbf{n}}$ is the direction of privileged axis, and $\\hat{\\textbf{p}}$ is the direction of each SNe Ia sample to galactic coordinates) along with anisotropic parameter $\\delta=\\frac{A(\\hat{\\textbf{n}}.\\hat{\\textbf{p}})}{1+A(\\hat{\\textbf{n}}.\\hat{\\textbf{p}})}$. The luminosity distance is expanded with model-independent cosmographic parameters as a function of modified redshift $\\tilde{z}$. As the transformation matrix $M(n\\times n)$ is obtained to convert the Taylor series coefficients of isotropic luminosity distance to corresponding anisotropic parameters. These results culminate the ma...

  13. Computational analysis of vertical axis wind turbine arrays

    Science.gov (United States)

    Bremseth, J.; Duraisamy, K.

    2016-03-01

    Canonical problems involving single, pairs, and arrays of vertical axis wind turbines (VAWTs) are investigated numerically with the objective of understanding the underlying flow structures and their implications on energy production. Experimental studies by Dabiri (J Renew Sustain Energy 3, 2011) suggest that VAWTs demand less stringent spacing requirements than their horizontal axis counterparts and additional benefits may be obtained by optimizing the placement and rotational direction of VAWTs. The flowfield of pairs of co-/counter-rotating VAWTs shows some similarities with pairs of cylinders in terms of wake structure and vortex shedding. When multiple VAWTs are placed in a column, the extent of the wake is seen to spread further downstream, irrespective of the direction of rotation of individual turbines. However, the aerodynamic interference between turbines gives rise to regions of excess momentum between the turbines which lead to significant power augmentations. Studies of VAWTs arranged in multiple columns show that the downstream columns can actually be more efficient than the leading column, a proposition that could lead to radical improvements in wind farm productivity.

  14. On the spin-axis dynamics of a Moonless Earth

    International Nuclear Information System (INIS)

    The variation of a planet's obliquity is influenced by the existence of satellites with a high mass ratio. For instance, Earth's obliquity is stabilized by the Moon and would undergo chaotic variations in the Moon's absence. In turn, such variations can lead to large-scale changes in the atmospheric circulation, rendering spin-axis dynamics a central issue for understanding climate. The relevant quantity for dynamically forced climate change is the rate of chaotic diffusion. Accordingly, here we re-examine the spin-axis evolution of a Moonless Earth within the context of a simplified perturbative framework. We present analytical estimates of the characteristic Lyapunov coefficient as well as the chaotic diffusion rate and demonstrate that even in absence of the Moon, the stochastic change in Earth's obliquity is sufficiently slow to not preclude long-term habitability. Our calculations are consistent with published numerical experiments and illustrate the putative system's underlying dynamical structure in a simple and intuitive manner.

  15. RF generation in the DARHT Axis-II beam dump

    International Nuclear Information System (INIS)

    We have occasionally observed radio-frequency (RF) electromagnetic signals in the downstream transport (DST) of the second axis linear induction accelerator (LIA) at the dual-axis radiographic hydrodynamic testing (DARHT) facility. We have identified and eliminated some of the sources by eliminating the offending cavities. However, we still observe strong RF in the range 1 GHz t0 2 GHz occurring late in the ∼2-(micro)s pulse that can be excited or prevented by varying the downstream tune. The narrow frequency width (<0.5%) and near exponential growth at the dominant frequency is indicative of a beam-cavity interaction, and electro-magnetic simulations of cavity structure show a spectrum rich in resonances in the observed frequency range. However, the source of beam produced RF in the cavity resonance frequency range has not been identified, and it has been the subject of much speculation, ranging from beam-plasma or beam-ion instabilities to unstable cavity coupling.

  16. Actuator line modeling of vertical-axis turbines

    CERN Document Server

    Bachant, Peter; Wosnik, Martin

    2016-01-01

    To bridge the gap between high and low fidelity numerical modeling tools for vertical-axis (or cross-flow) turbines (VATs or CFTs), an actuator line model (ALM) was developed and validated for both a high and a medium solidity vertical-axis turbine at rotor diameter Reynolds numbers $Re_D \\sim 10^6$. The ALM is a hybridization of classical blade element theory with Navier--Stokes based flow models, and in this study both $k$--$\\epsilon$ Reynolds-averaged Navier--Stokes (RANS) and Smagorinsky large eddy simulation (LES) turbulence models were tested. The RANS models were able to be run on coarse grids while still providing good convergence behavior in terms of the mean power coefficient, and also approximately four orders of magnitude reduction in computational expense compared with 3-D blade-resolved RANS simulations. Submodels for dynamic stall, end effects, added mass, and flow curvature were implemented, resulting in reasonable performance predictions for the high solidity rotor, more discrepancies for the...

  17. Magnetic Axis and Geometric Measurement for the LHC Cryomagnet

    CERN Document Server

    Bajko, M; García-Pérez, J; Gorskaya, E A; Koltin, G; Rijllart, A

    2003-01-01

    The LHC cryomagnets are made with several types of magnets which all need to be aligned. Both magnetic and geometric axis need to be well known before the installation in the LHC tunnel. These measurements require integrated controls for optical, magnetic and geometric measurements systems. The measurement sequence as well as the analysis should be adapted to each type of magnet. To perform the measurement, a mole, equipped with a reflector, a CCD camera and Hall probe sensors should be moved along the tubes of the 15 metres long dipole magnets and rotated around its axis. The geometrical measurements are made with an industrial Laser Tracker system. Homemade systems have been developed for the image and magnetic measurements. Each part can be driven separately and form the lower layer of the system. The control, as well as the interaction of these systems, has been integrated into a single system using UDP communication. The harmonic analysis allows verification of the quality and the orientation of the magn...

  18. CFD Simulation of Twin Vertical Axis Tidal Turbines System

    Directory of Open Access Journals (Sweden)

    Syed Shah Khalid

    2013-01-01

    Full Text Available As concerns about rising fossil-fuel prices, energy security and climate-change increase, renewable energy can play a vital role in producing local, clean and inexhaustible energy to supply world rising demand for electricity. In this study, hydrodynamic analysis of vertical axis tidal turbine operating side-by-side is numerically analyzed. Two-dimensional numerical modeling of the unsteady flow through the blades of the turbine is performed using ANSYS CFX, hereafter CFX; this is based on a Reynolds-Averaged Navier-Stokes (RANS model. The purpose is to find an optimal distance between the turbines where interaction effect is minimal and constructive, where the turbines operate more efficiently than stand alone turbine. A transient simulation is done on Vertical Axis Tidal Turbine (VATT using the Shear Stress Transport Turbulence (SST model. Main hydrodynamic parameters like torque T, coefficients of performance CP and coefficient of torque CT are investigated. The gap spacing between the turbines has an important role in performance improvement and also in vortex shedding suppression for the flows around two counters rotating systems. The simulation results are validated with Ye and Calisal data. The results of this study prove that the total power output of a twin-turbine system with an optimal layout can be about 24% higher than two times that of a stand-alone turbine. We conclude that the optimally configured counter-rotating twin turbines should be a side-by-side arrangement.

  19. A novel dual-axis optoelectronic level with refraction principle

    International Nuclear Information System (INIS)

    Levels are fundamental metrological tools for machine leveling and angle measurements. Current levels are all based on the pendulum principle and bubble vial principle. The former is precise but complicated, while the latter is not precise enough. This paper presents a novel, simple and precise optoelectronic level. It is based on the principle of light refraction in the transparent and viscous fluid. The fluid surface is always in leveling condition regardless whether the ground is level or not. Measuring the refraction angle with precise dual-axis autocollimator can directly reflect the inclined angle of the level. A leakage prevention design is also proposed to allow the level to be placed in any pose. Calibrated by an angular interferometer, the error of the dual-axis optoelectronic level is better than ±0.7 arcsec in the measuring range of ±100 arcsec, and better than ±0.4 arcsec for the range of ±30 arcsec, for both axes. Without the need of a pendulum mechanism, this is a simpler design for precision level. (paper)

  20. The methods of the LHC magnets' magnetic axis location measurement

    International Nuclear Information System (INIS)

    More than 8 thousands LHC magnets of various types will be extensively measured during series magnetic test at both room and superfluid helium temperature. The precise knowledge of the magnetic axis positioning is vital for the alignment of those magnets in the tunnel. The most efficient and cost effective method with rotating pick up coil is chosen currently as a baseline for series measurement. The position of the measuring coil axis herewith is measured with a dedicated optical system. The deflection of the light beam in the air due to temperature gradient either passing through the cold bore when the magnet excited for warm measurement or through the anti-cryostat during cold measurement can reach magnitudes significantly exceeding tolerance and therefore is a critical issue. We present studies of the light deflection in 10 m long dipole at warm and cold and propose means to reduce it. The result of the dipole centring powered in Quadrupole Configured Dipole (QCD) or 'ugly quad' configuration and correlation with centring based on high order harmonics are presented as well. (authors)

  1. Optimization of blade motion of vertical axis turbine

    Science.gov (United States)

    Ma, Yong; Zhang, Liang; Zhang, Zhi-yang; Han, Duan-feng

    2016-04-01

    In this paper, a method is proposed to improve the energy efficiency of the vertical axis turbine. First of all, a single disk multiple stream-tube model is used to calculate individual fitness. Genetic algorithm is adopted to optimize blade pitch motion of vertical axis turbine with the maximum energy efficiency being selected as the optimization objective. Then, a particular data processing method is proposed, fitting the result data into a cosine-like curve. After that, a general formula calculating the blade motion is developed. Finally, CFD simulation is used to validate the blade pitch motion formula. The results show that the turbine's energy efficiency becomes higher after the optimization of blade pitch motion; compared with the fixed pitch turbine, the efficiency of variable-pitch turbine is significantly improved by the active blade pitch control; the energy efficiency declines gradually with the growth of speed ratio; besides, compactness has lager effect on the blade motion while the number of blades has little effect on it.

  2. Preferred axis of CMB parity asymmetry in the masked maps

    Science.gov (United States)

    Cheng, Cheng; Zhao, Wen; Huang, Qing-Guo; Santos, Larissa

    2016-06-01

    Both WMAP and Planck data show a significant odd-multipole preference in the large scales of the cosmic microwave background (CMB) temperature anisotropies. If this pattern originates from cosmological effects, then it can be considered a crucial clue for a violation in the cosmological principle. By defining various direction dependent statistics in the full-sky Planck 2015 maps (see, for instance, Naselsky et al. (2012); W. Zhao (2014)), we found that the CMB parity asymmetry has a preferred direction, which is independent of the choices of the statistics. In particular, this preferred axis is strongly aligned with those in the CMB quadrupole and octopole, as well as that in the CMB kinematic dipole, which hints to their non-cosmological origin. In realistic observations, the foreground residuals are inevitable, and should be properly masked out in order to avoid possible misinterpretation of the results. In this paper, we extend our previous analyses to the masked Planck 2015 data. By defining a similar direction dependent statistic in the masked map, we find a preferred direction of the CMB parity asymmetry, in which the axis also coincides with that found in the full-sky analysis. Therefore, our conclusions on the CMB parity violation and its directional properties are confirmed.

  3. Simplified aeroelastic modeling of horizontal axis wind turbines

    Science.gov (United States)

    Wendell, J. H.

    1982-09-01

    Certain aspects of the aeroelastic modeling and behavior of the horizontal axis wind turbine (HAWT) are examined. Two simple three degree of freedom models are described in this report, and tools are developed which allow other simple models to be derived. The first simple model developed is an equivalent hinge model to study the flap-lag-torsion aeroelastic stability of an isolated rotor blade. The model includes nonlinear effects, preconing, and noncoincident elastic axis, center of gravity, and aerodynamic center. A stability study is presented which examines the influence of key parameters on aeroelastic stability. Next, two general tools are developed to study the aeroelastic stability and response of a teetering rotor coupled to a flexible tower. The first of these tools is an aeroelastic model of a two-bladed rotor on a general flexible support. The second general tool is a harmonic balance solution method for the resulting second order system with periodic coefficients. The second simple model developed is a rotor-tower model which serves to demonstrate the general tools. This model includes nacelle yawing, nacelle pitching, and rotor teetering. Transient response time histories are calculated and compared to a similar model in the literature. Agreement between the two is very good, especially considering how few harmonics are used. Finally, a stability study is presented which examines the effects of support stiffness and damping, inflow angle, and preconing.

  4. Application of Circulation Controlled Blades for Vertical Axis Wind Turbines

    Directory of Open Access Journals (Sweden)

    Velissarios Kourkoulis

    2013-07-01

    Full Text Available The blades of a vertical axis wind turbine (VAWT rotor see an inconsistent angle of attack through its rotation. Consequently, VAWT blades generally use symmetrical aerofoils with a lower lift-to-drag ratio than cambered aerofoils tailored to maximise horizontal axis wind turbine rotor performance. This paper considers the feasibility of circulation controlled (CC VAWT blades, using a tangential air jet to provide lift and therefore power augmentation. However CC blade sections require a higher trailing-edge thickness than conventional sections giving rise to additional base drag. The choice of design parameters is a compromise between lift augmentation, additional base drag as well as the power required to pump the air jet. Although CC technology has been investigated for many years, particularly for aerospace applications, few researchers have considered VAWT applications. This paper considers the feasibility of the technology, using Computational Fluid Dynamics to evaluate a baseline CC aerofoil with different trailing-edge ellipse shapes. Lift and drag increments due to CC are considered within a momentum based turbine model to determine net power production. The study found that for modest momentum coefficients significant net power augmentation can be achieved with a relatively simple aerofoil geometry if blowing is controlled through the blades rotation.

  5. Manufacturing of injection moulding tool with five axis milling machine

    Directory of Open Access Journals (Sweden)

    I. Micetic

    2013-05-01

    Full Text Available Purpose: The main intention of this paper is to show the advanced technology for production of the electrode for EDM that has a relatively complex geometry. Five axes CNC machining centre is used for production of an example ice scrapers since application of other type of machine requires a lot of auxiliary time and resources.Design/methodology/approach: Advanced manufacturing technology involves the application of various software tools and technologies, among them the tools and technology to automate the design, analysis, testing and manufacturing occupy a key position.Findings: The main outcomes are decrease of production time, better quality of surface and product geometry. Decrease of cutting time refers to decrease of number of used tools, preparation time is lower in comparison with conventional machines.Research limitations/implications: The practical part included the design of electrode in the CAD system, SolidWorks 2010, production of NC program for the operating unit Haidenhain iTNC 530 in CAM system ESPRIT 2010, and finally making the electrode on five axis machine center DMG DMU 40 Monoblock. Originality/value: Presented technology for a five-axis machining centre, ensures a great advantages in the process preparation while reduced set-up time, reduced number of required accessories and devices, reduced number of special tools is needed. This knowledge can support the development and design of technological processes.

  6. Eight Pulse Performance of DARHT Axis II - Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, Martin E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-08

    The DARHT-II accelerator produces a 1.65-kA, 17-MeV beam in a 1600-ns pulse. Standard operation of the DARHT Axis II accelerator involves extracting four short pulses from the 1.6 us long macro-pulse produced by the LIA. The four short pulses are extracted using a fast kicker in combination with a quadrupole septum magnet and then transported for several meters to a high-Z material target for conversion to x-rays for radiography. The ability of the DARHT Axis 2 kicker to produce more than the standard four pulse format has been previously demonstrated. This capability was developed to study potential risks associated with beam transport during an initial commissioning phase at low energy (8 MeV) and low current (1.0 kA).The ability of the kicker to deliver more than four pulses to the target has been realized for many years. This note describes the initial results demonstrating this capability.

  7. PRIGo: a new multi-axis goniometer for macromolecular crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Waltersperger, Sandro; Olieric, Vincent, E-mail: vincent.olieric@psi.ch; Pradervand, Claude [Paul Scherrer Institute, Villigen PSI (Switzerland); Glettig, Wayne [Centre Suisse d’Electronique et Microtechnique SA, Neuchâtel 2002 (Switzerland); Salathe, Marco; Fuchs, Martin R.; Curtin, Adrian; Wang, Xiaoqiang; Ebner, Simon; Panepucci, Ezequiel; Weinert, Tobias [Paul Scherrer Institute, Villigen PSI (Switzerland); Schulze-Briese, Clemens [Dectris Ltd, Baden 5400 (Switzerland); Wang, Meitian, E-mail: vincent.olieric@psi.ch [Paul Scherrer Institute, Villigen PSI (Switzerland)

    2015-05-09

    The design and performance of the new multi-axis goniometer PRIGo developed at the Swiss Light Source at Paul Scherrer Institute is described. The Parallel Robotics Inspired Goniometer (PRIGo) is a novel compact and high-precision goniometer providing an alternative to (mini-)kappa, traditional three-circle goniometers and Eulerian cradles used for sample reorientation in macromolecular crystallography. Based on a combination of serial and parallel kinematics, PRIGo emulates an arc. It is mounted on an air-bearing stage for rotation around ω and consists of four linear positioners working synchronously to achieve x, y, z translations and χ rotation (0–90°), followed by a ϕ stage (0–360°) for rotation around the sample holder axis. Owing to the use of piezo linear positioners and active correction, PRIGo features spheres of confusion of <1 µm, <7 µm and <10 µm for ω, χ and ϕ, respectively, and is therefore very well suited for micro-crystallography. PRIGo enables optimal strategies for both native and experimental phasing crystallographic data collection. Herein, PRIGo hardware and software, its calibration, as well as applications in macromolecular crystallography are described.

  8. Feasibility and optical performance of one axis three positions sun-tracking polar-axis aligned CPCs for photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Runsheng; Yu, Yamei [Education Ministry Key Laboratory of Advanced Technology and Preparation for Renewable Energy Materials, Yunnan Normal University, Kunming 650092 (China)

    2010-09-15

    A new design concept, called one axis three positions sun-tracking polar-axis aligned CPCs (3P-CPCs, in short), was proposed and theoretically studied in this work for photovoltaic applications. The proposed trough-like CPC is oriented in the polar-axis direction, and the aperture is daily adjusted eastward, southward, and westward in the morning, noon and afternoon, respectively, by rotating the CPC trough, to ensure efficient collection of beam radiation nearly all day. To investigate the optical performance of such CPCs, an analytical mathematical procedure is developed to estimate daily and annual solar gain captured by such CPCs based on extraterrestrial radiation and monthly horizontal radiation. Results show that the acceptance half-angle of 3P-CPCs is a unique parameter to determine their optical performance according to extraterrestrial radiation, and the annual solar gain stays constant if the acceptance half-angle, {theta}{sub a}, is less than one third of {omega}{sub 0,min}, the sunset hour angle in the winter solstice, otherwise decreases with the increase of {theta}{sub a}. For 3P-CPCs used in China, the annual solar gain, depending on the climatic conditions in site, decreased with the acceptance half-angle, but such decrease was slow for the case of {theta}{sub a}{<=}{omega}{sub 0,min}/3, indicating that the acceptance half-angle should be less than one third of {omega}{sub 0,min} for maximizing annual energy collection. Compared to fixed east-west aligned CPCs (EW-CPCs) with a yearly optimal acceptance half-angle, the fixed south-facing polar-axis aligned CPCs (1P-CPCs) with the same acceptance half-angle as the EW-CPCs annually collected about 65-74% of that EW-CPCs did, whereas 3P-CPCs annually collected 1.26-1.45 times of that EW-CPCs collected, indicating that 3P-CPCs were more efficient for concentrating solar radiation onto their coupling solar cells. (author)

  9. Fracture fixation of the Odontoid process of the axis through an osseous-axis pin in Cuba. A case report.

    Directory of Open Access Journals (Sweden)

    José Ramón Tejera del Valle

    2005-11-01

    Full Text Available The fractures of the odontoid process of the Axis has been a polemic topic for many years. The alternative technique of placing a fixation screw directly across the fracture site, reattaching the odontoid to the body of C2 had been gained defensors in the actuality in the world. The topic was reviewed, and the seventh case knowned was been operated in Cuba by this technique was presented. This intervention was realized in the Department of Neurosurgery of Cienfuegos. Current considerations are emitted.

  10. Network of off-axis melt bodies at the East Pacific Rise

    Science.gov (United States)

    Canales, J. P.; Carton, H.; Carbotte, S. M.; Mutter, J. C.; Nedimović, M. R.; Xu, M.; Aghaei, O.; Marjanović, M.; Newman, K.

    2012-04-01

    Magmatic accretion of new oceanic crust at intermediate- to fast-spreading mid-ocean ridges occurs along a narrow axial zone. This zone is characterized by molten sills in the crust that are emplaced within about 3km of the ridge axis and overlie a zone of elevated temperatures and partial melt. There are disparate indications of off-axis magmatism and lavas erupted in the near-axis region are more compositionally variable than in the axial zone. Here we present three-dimensional seismic reflection images from the fast-spreading East Pacific Rise that reveal a network of sills 4 to 8km east of the ridge axis. Our crustal model, constrained using seismic velocity and attenuation data, shows that the sills are located outside of the main axial zone of crustal accretion, and above a region containing partial melt. We infer that the sills represent sites of sustained off-axis magmatism. Pockets of melt extend from the off-axis sills to the axial zone and may represent melt migration pathways. These pathways could promote mixing between enriched off-axis melts and normal on-axis melts, contributing to the compositional variability of the near-axis lavas. We suggest that off-axis magmatism occurs preferentially, but not exclusively, where pre-existing fractures inherited from offsets of the spreading axis promote melt transport from the mantle into the crust.

  11. Optical performance of inclined south-north single-axis tracked solar panels

    International Nuclear Information System (INIS)

    To investigate optical performance of the inclined south-north single-axis (ISN-axis, in short) tracked solar panels, a mathematical procedure to estimate the annual collectible radiation on fixed and tracked panels was suggested based on solar geometry and monthly horizontal radiation. For solar panels tracking about ISN-axis, the yearly optimal tilt-angle of ISN-axis for maximizing annual solar gain was about 3o deviating from the site latitude in most of China except in areas with poor solar resources, and the maximum annual collectible radiation on ISN-axis tracked panels was about 97-98% of that on dual-axis tracked panels; whereas for ISN-axis tracked panels with the tilt-angle of ISN-axis being adjusted four times in a year at three fixed tilt-angles, the annual collectible radiation was almost close to that on dual-axis tracked panels, the optimum date of tilt-angle adjustment of ISN-axis was 23 days from the equinoxes, and the optimum tilt-angle adjustment value for each adjustment was about 22o. Compared to fixed south-facing solar panels inclined at an optimal tilt-angle, the increase in the annual solar gain due to using ISN-axis sun tracking was above 30% in the areas with abundant solar resources and less than 20% in the areas with poor solar resources.

  12. Comparison of Efficiencies of Solar Tracker systems with static panel Single- Axis Tracking System and Dual-Axis Tracking System with Fixed Mount

    Directory of Open Access Journals (Sweden)

    Dhanabal.R

    2013-04-01

    Full Text Available Electricity plays a key role now in our daily lives but the energy sources to electric power has been used in abundance and so researchers were compelled to find an alternate source of power leading to the discovery of solar energy. Solar energy is inexhaustible and eco-friendly and can be converted into electricityusing photovoltaic panels. These panels can be used in a fixed form or used in a solar tracking system for single axis as well as for dual axis. In a fixed form their efficiency is low since the panels will be tilted in a particular angle whereas in a tracking system the panel is made to move either in single axis or dual axis. In a single axis system the panel is moved in an east to west direction with respect to the sun and it has better efficiency than panels in fixed form. But in a dual axis system the panel is made to rotate in all four directions in accordance with the sun. And dual axis has proved to have more efficiency than both fixed panels and single axis system.

  13. Usefulness of the long-axis and short-axis reformatted images of multidetector-row CT in evaluating T-factor of the surgically resected pancreaticobiliary malignancies

    International Nuclear Information System (INIS)

    Purpose: To evaluate the diagnostic efficacy of curved planar reformations along the duct (long-axis CPR) and series of reformations perpendicular to the duct (short-axis MPR) in evaluating T-factors of pancreaticobiliary malignancy. Materials and methods: Twenty-five patients with surgically proven pancreaticobiliary malignancy (12 bile duct cancers and 13 pancreas cancers) were evaluated. A dynamic study was performed with multidetector-row CT with four detectors, and reconstructed with 1 mm thickness and intervals. Tracing the center of the duct system on axial images, long-axis CPR images and serial short-axis MPR images were obtained. Two radiologists interpreted the T factor of the diseases three times: session (1), axial images only; session (2), axial, coronal and sagittal multiplanar reformation images; and session (3), axial, long-axis CPR, and short-axis MPR images. Receiver operating characteristic curves were analyzed. Results: In evaluations of bile duct cancer, Az values of (3) (0.95, 0.92) were higher than those of (1) (0.89, 0.88) and (2) (0.92, 0.89), with some significant differences. In evaluations of pancreas cancer, Az values of all interpretations were almost equal. Conclusion: Long-axis CPR and short-axis MPR images were suggested to be useful as additional images to the original axial images in evaluating the local extension of bile duct carcinomas

  14. The SFD - 80 M high precision double axis facing lathe

    International Nuclear Information System (INIS)

    A high precision double axis facing lathe was designed for machining the 'final end-cup' by exterior conical lathing. The lathe is semi-automatic and includes two independent identical units. The general constructive, dimensional and functional characteristics are presented as well as the specific power consumptions. As compared to other machines able to perform the same operations this machine presents the following novel aspects: - it is dedicated from the design stage to the workpiece to be machined; - the splinting speed is quasi-constant all along the processing span (irrespective of the cutting diameter at which the tool is fixed, in its trajectory generating the exterior cone). At 100% and 80% nominal power values the yield is 240 workpiece/hour and 192 workpiece/hour, respectively

  15. Software tool for horizontal-axis wind turbine simulation

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, A.J. [Instituto Argentino de Oceanografia, Camino La Carrindanga Km. 7, 5 CC 804, B8000FWB Bahia Blanca (Argentina); Universidad Tecnologica Nacional Facultad Regional Bahia Blanca, GESE, 11 de Abril 461, B8000LMI Bahia Blanca (Argentina); Dpto. de Ing. Electrica y de Computadoras, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Rossi, A.P. [Universidad Tecnologica Nacional Facultad Regional Bahia Blanca, GESE, 11 de Abril 461, B8000LMI Bahia Blanca (Argentina); Dpto. de Ing. Electrica y de Computadoras, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2008-07-15

    The main problem of a wind turbine generator design project is the design of the right blades capable of satisfying the specific energy requirement of an electric system with optimum performance. Once the blade has been designed for optimum operation at a particular rotor angular speed, it is necessary to determine the overall performance of the rotor under the range of wind speed that it will encounter. A software tool that simulates low-power, horizontal-axis wind turbines was developed for this purpose. With this program, the user can calculate the rotor power output for any combination of wind and rotor speeds, with definite blade shape and airfoil characteristics. The software also provides information about distribution of forces along the blade span, for different operational conditions. (author)

  16. A three-axis SQUID-based absolute vector magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Schönau, T.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, H.-G. [Department of Quantum Detection, Leibniz Institute of Photonic Technology, Jena 07745 (Germany); Zakosarenko, V.; Meyer, M. [Supracon AG, An der Lehmgrube 11, Jena 07751 (Germany)

    2015-10-15

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz{sup 1/2}. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  17. A three-axis SQUID-based absolute vector magnetometer

    Science.gov (United States)

    Schönau, T.; Zakosarenko, V.; Schmelz, M.; Stolz, R.; Anders, S.; Linzen, S.; Meyer, M.; Meyer, H.-G.

    2015-10-01

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth's magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz1/2. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration.

  18. Development of Rotary Axis For Wire Electrical Discharge Machining (WEDM

    Directory of Open Access Journals (Sweden)

    M. Parthiban, C. Manigandan, G. Muthu Venkadesh, M. Ranjith Kumar

    2013-08-01

    Full Text Available This paper gives an overview of setting up a rotary axis to the existing WEDM machine to investigate the machining parameters in WEDG of harder materials. There are a number of hybrid machining processes (HMPs seeking the combined advantage of EDM and other machining techniques. One such combination is wire electrical discharge grinding (WEDG, which is commonly used for micro-machining of fine and hard rods. WEDG employs a single wire guide to confine the wire tension within the discharge area between the rod and the front edge of the wire and also to minimize the wire vibration. Other advantages of WEDG include the ability to machine hard- to- machine materials with large aspect ratio.

  19. Magnetoresistance in magnetite: Switching of the magnetic easy axis

    International Nuclear Information System (INIS)

    The influence of the external magnetic field B (B ≤ 4 T) on resistivity in magnetite single crystal was studied at few temperatures both below and above the Verwey transition temperature TV, and in two type cubic directions. We have succeeded to confirm our predictions that the magnetic axis switching affects electronic transport. It was also found that the transverse resistivity (B -perpendicular current direction) exceeds longitudinal one, but only for T > TV, with no obvious systematics below the transition temperature. This may indicate that atomic disorder, inherent and poorly defined in a material with structural domains, is the primary factor that governs transport properties below the transition temperature. Finally, and concomitant with the last statement, only very small magnetic field dependence in magnetite below TV may be inferred from our data.

  20. A Multi-axis Control Board Implemented via an FPGA

    Science.gov (United States)

    Longo, Domenico; Muscato, Giovanni

    Most of robotic applications rely on the use of DC motors with quadrature encoder feedback. Typical applications are legged robots or articulated chassis multi-wheeled robots. In these applications system designer must implement multi-axis control systems able to handle an high number of quadrature encoder signals and to generate the same number of PWM signals. Moreover the adopted CPU must be able to execute the same number of control loop algorithms in a time slot of about ten milliseconds. Very few commercial SoC (System on Chip) can handle up to six channels. In this work the implementation of a SoC on FPGA able to handle up to 20 channels within a time slot of 20 ms and up to 100 channels within a time slot of 100 ms is described. In order to demonstrate the effectiveness of the design, the board was used to control a small six wheels outdoor robot.

  1. Lightcurves and the axis of rotation of 433 Eros

    Science.gov (United States)

    Dunlap, J. L.

    1976-01-01

    Ten lightcurves and UBV photometry of 433 Eros were obtained between August 1972 and May 1975. The absolute magnitude of the lightcurve maximum is 10.75 and the phase coefficient is 0.025 mag/deg. There may be a small difference in B-V color between the northern and southern hemispheres. The pole of the axis of rotation is directed toward 16 deg, ecliptic longitude and 12 deg ecliptic latitude, respectively, and the rotation is direct with a sidereal period of 5 hr 16 min 13.4 sec. The dimensions derived from the polarimetric albedo and the lightcurve amplitudes are 12 km by 12 km by 31 km for a smooth cylinder with hemispherical ends.

  2. A three-axis SQUID-based absolute vector magnetometer

    International Nuclear Information System (INIS)

    We report on the development of a three-axis absolute vector magnetometer suited for mobile operation in the Earth’s magnetic field. It is based on low critical temperature dc superconducting quantum interference devices (LTS dc SQUIDs) with sub-micrometer sized cross-type Josephson junctions and exhibits a white noise level of about 10 fT/Hz1/2. The width of superconducting strip lines is restricted to less than 6 μm in order to avoid flux trapping during cool-down in magnetically unshielded environment. The long-term stability of the flux-to-voltage transfer coefficients of the SQUID electronics is investigated in detail and a method is presented to significantly increase their reproducibility. We further demonstrate the long-term operation of the setup in a magnetic field varying by about 200 μT amplitude without the need for recalibration

  3. K-shell ionization under zone axis electron diffraction conditions

    International Nuclear Information System (INIS)

    A comprehensive theoretical treatment for the inelastic scattering of fast electrons in a crystalline environment is applied to account for variations in characteristic x-ray emission rates from spinel and chromia under zone axis diffraction conditions for 300 keV electrons. X-ray counts as well as backscattered electron contrast are recorded as the beam is tilted by about 70 mrad on a two-dimensional scan raster. Calculated K-shell ionization and backscattering cross sections, based on a model which takes into account interaction delocalization, thermal diffuse scattering and the consequent thickness dependent channelling effects in a realistic way, are in good agreement with experiment. 43 refs., 13 figs

  4. Nonlinear characterization of a single-axis acoustic levitator

    Science.gov (United States)

    Andrade, Marco A. B.; Ramos, Tiago S.; Okina, Fábio T. A.; Adamowski, Julio C.

    2014-04-01

    The nonlinear behavior of a 20.3 kHz single-axis acoustic levitator formed by a Langevin transducer with a concave radiating surface and a concave reflector is experimentally investigated. In this study, a laser Doppler vibrometer is applied to measure the nonlinear sound field in the air gap between the transducer and the reflector. Additionally, an electronic balance is used in the measurement of the acoustic radiation force on the reflector as a function of the distance between the transducer and the reflector. The experimental results show some effects that cannot be described by the linear acoustic theory, such as the jump phenomenon, harmonic generation, and the hysteresis effect. The influence of these nonlinear effects on the acoustic levitation of small particles is discussed.

  5. Parametric study of single-axis acoustic levitation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, W. J.; Wei, B.

    2001-08-06

    Remarkable enhancement of the single-axis acoustic levitation force is achieved by properly curving the surface and enlarging the section of the reflector so as to levitate high density material like tungsten ({rho}{sub s}=18.92g/cm{sup 3}). A two-cylinder model incorporating the boundary element method simulations is presented for systematic study of the relationship between levitation capabilities and geometric parameters. The model proves to be successful in predicting resonant modes and explaining deviation of the levitated samples near the reflector and driver. The dependence of levitation force on resonant mode, reflector section radius R{sub b} and curvature radius R is revealed and summarized, which agrees with the experiment in principle and suggests that a reflector with large R{sub b} and small R (when R{sub b}/{lambda}{>=}0.982) working under mode 1 assures better levitation capabilities. {copyright} 2001 American Institute of Physics.

  6. Nonlinear characterization of a single-axis acoustic levitator

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Marco A. B. [Institute of Physics, University of São Paulo, São Paulo (Brazil); Ramos, Tiago S.; Okina, Fábio T. A.; Adamowski, Julio C. [Department of Mechatronics and Mechanical Systems Engineering, Escola Politécnica, University of São Paulo, São Paulo (Brazil)

    2014-04-15

    The nonlinear behavior of a 20.3 kHz single-axis acoustic levitator formed by a Langevin transducer with a concave radiating surface and a concave reflector is experimentally investigated. In this study, a laser Doppler vibrometer is applied to measure the nonlinear sound field in the air gap between the transducer and the reflector. Additionally, an electronic balance is used in the measurement of the acoustic radiation force on the reflector as a function of the distance between the transducer and the reflector. The experimental results show some effects that cannot be described by the linear acoustic theory, such as the jump phenomenon, harmonic generation, and the hysteresis effect. The influence of these nonlinear effects on the acoustic levitation of small particles is discussed.

  7. IDENTIFICATION OF GYRO DRIFTS UNDER THREE AXIS ATTITUDE COUPLING

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Optical gyros and star sensors are primary measurement hardware in an attitude control system with high accuracy.The drifts of the optical gyros, however, make an unfavorable impact on the accuracy of the attitude control system.In order for compensations to be provided, this paper presents a least-square method to identify the optical gyro drifts by using flight attitude data from the star sensors and the optical gyros.Equations for identification are formulated by quaternion.Integration of the identification equations and the data from the star sensors are utilized to form a least-square index, in which lower sampling frequency of the star sensors than that of the optical gyros is dealt with effectively.An iterative identification algorithm is presented to minimize the index.Identification procedure under three-axis attitude coupling is illustrated .Simulation results show the effectiveness of the method presented.Proper sample size and sampling frequency are also recommended.

  8. Dynamic behavior analysis for a six axis industrial machining robot

    CERN Document Server

    Bisu, Claudiu-Florinel; Gérard, Alain; K'Nevez, Jean-Yves

    2012-01-01

    The six axis robots are widely used in automotive industry for their good repeatability (as defined in the ISO92983) (painting, welding, mastic deposition, handling etc.). In the aerospace industry, robot starts to be used for complex applications such as drilling, riveting, fiber placement, NDT, etc. Given the positioning performance of serial robots, precision applications require usually external measurement device with complexes calibration procedure in order to reach the precision needed. New applications in the machining field of composite material (aerospace, naval, or wind turbine for example) intend to use off line programming of serial robot without the use of calibration or external measurement device. For those applications, the position, orientation and path trajectory precision of the tool center point of the robot are needed to generate the machining operation. This article presents the different conditions that currently limit the development of robots in robotic machining applications. We ana...

  9. Three axis rotational maneuver and vibration stabilization of elastic spacecraft

    Science.gov (United States)

    Singh, Sahjendra N.

    1987-01-01

    A control law for three-axis rotational maneuvers of a spacecraft beam-tip body configuration based on non-linear inversion and modal velocity feedback is presented. A decoupling attitude control law is presented such that in the closed-loop system the attitude angles of the spacecraft are independently controlled, using the control moments acting on the space vehicle. This controller asymptotically decouples the flexible dynamics from the rigid one and also allows the decomposition of the elastic dynamics into two subsystems representing the transverse deflections of the beam in two orthogonal planes. These low-order subsystems are used for the derivation of a modal velocity feedback stabilizer using the force and moment actuators at the end body. Simulation results are presented to show the capability of the controller.

  10. Optimization model for rotor blades of horizontal axis wind turbines

    Institute of Scientific and Technical Information of China (English)

    LIU Xiong; CHEN Yan; YE Zhiquan

    2007-01-01

    This paper presents an optimization model for rotor blades of horizontal axis wind turbines. The model refers to the wind speed distribution function on the specific wind site, with an objective to satisfy the maximum annual energy output. To speed up the search process and guarantee a global optimal result, the extended compact genetic algorithm (ECGA) is used to carry out the search process.Compared with the simple genetic algorithm, ECGA runs much faster and can get more accurate results with a much smaller population size and fewer function evaluations. Using the developed optimization program, blades of a 1.3 MW stall-regulated wind turbine are designed. Compared with the existing blades, the designed blades have obviously better aerodynamic performance.

  11. Role of the fibroblast growth factor receptor axis in cholangiocarcinoma.

    Science.gov (United States)

    Ang, Celina

    2015-07-01

    Advanced cholangiocarcinoma (CCA) is a highly lethal disease with limited therapeutic options beyond cytotoxic chemotherapy. Molecular profiling of CCA has provided insights into the pathogenesis of this disease and identified potential therapeutic targets. The fibroblast growth factor receptor (FGFR) axis is important for maintaining tissue homeostasis. Aberrations in FGFR activity have been implicated in the development and progression of CCA and other malignancies, which has generated significant interest in exploring FGFR's therapeutic potential. FGFR2 fusion events are present in up to 17% of intrahepatic CCAs and appear to predict sensitivity to FGFR inhibitors even after progression on chemotherapy. These observations have led to a clinical trial evaluating FGFR inhibition in patients with CCA enriched for FGFR alterations. This review summarizes current knowledge about the role of the FGFR pathway in cholangiocarcinogenesis and ongoing work in developing FGFR-directed therapies as an antineoplastic strategy for CCA. PMID:25678238

  12. Design and Analysis of Horizontal Axis Wind Turbine Rotor

    Directory of Open Access Journals (Sweden)

    Arvind Singh Rathore

    2011-11-01

    Full Text Available This paper presents an optimization model for rotor design of 750 kW horizontal axis wind turbine. The wind turbine blade is a very important part of the rotor. In this work a blade of length 21.0 m is taken and airfoil for the blade is S809. The airfoil taken is same from root to tip. The model refers to a design method based on TypeApproval Provision Scheme TAPS-2000. All the loads caused by wind and inertia on the blades are transferred to the hub. The stress and deflection were calculated on blades and hub by Finite element analysis method. Result obtained from ANSYS is compared with the existing design.

  13. Aerodynamic performance of vertical and horizontal axis wind turbines

    Science.gov (United States)

    Maydew, R. C.; Klimas, P. C.

    1981-06-01

    The aerodynamic performance of vertical and horizontal axis wind turbines is investigated, and comparison of data of the 17-m Darrieus VAWT with the 60.7-m Mod-1 HAWT and 37.8-m Mod-0A HAWT is discussed. It is concluded that the maximum average measured power coefficients of the VAWT are about 0%-15% higher than those of the HAWTs. It is suggested that vertical wind shear may have lowered the Mod-1 HAWT aerodynamic performance, but, the magnitude of this effect could not be evaluated. It is included that generalizations which refer to the Darrieus VAWT as aerodynamically less efficient than the HAWT should be used carefully.

  14. Strain measurements in ferromagnetic martensitic Heuslers and magnetization easy axis

    International Nuclear Information System (INIS)

    The temperature-dependence of strain under constant magnetic-fields is studied in Ni-Mn-X (X:Ga,In,Sn,Sb) and Ni-Mn-In-X (X:Ga,Sn,Sb) polycrystalline ferromagnetic Heusler alloys which undergo a martensitic transformation close to room-temperature. The applied magnetic-field influences the nucleation of martensite so that decreasing the temperature under a magnetic field leads to large length changes between the austenite and martensite states. The length-change within the martensitic state varies with the magnitude of the cooling-field. This is related to the variant-orientation during martensite nucleation. These strain-data provide information on the easy axis of magnetization

  15. A Multi-Fork Z-Axis Quartz Micromachined Gyroscope

    Directory of Open Access Journals (Sweden)

    Aiying Yang

    2013-09-01

    Full Text Available A novel multi-fork z-axis gyroscope is presented in this paper. Different from traditional quartz gyroscopes, the lateral electrodes of the sense beam can be arranged in simple patterns; as a result, the fabrication is simplified. High sensitivity is achieved by the multi-fork design. The working principles are introduced, while the finite element method (FEM is used to simulate the modal and sensitivity. A quartz fork is fabricated, and a prototype is assembled. Impedance testing shows that the drive frequency and sense frequency are similar to the simulations, and the quality factor is approximately 10,000 in air. The scale factor is measured to be 18.134 mV/(°/s and the nonlinearity is 0.40% in a full-scale input range of ±250 °/s.

  16. An electromagnetically levitated two-axis gimbaless pointing mechanism

    Science.gov (United States)

    Volpe, Gerald T.

    A brief description for a proposed new pointing mechanism which requires no mechanical gimbals, is virtually friction free, and is vibration isolated from a ground support system or vehicle is presented. The device uses electromagnetic forces for support levitation and pointing, both being accomplished from a ground reference thereby leaving the payload virtually free from a remotely located command center. Solid pointing angles of almost 2(pi) steradians are achievable, limited only by structural interference. A third degree-of-freedom tilt axis can be added at will, but will not be elaborated. Although the system is primarily intended for space vehicles in a micro-gravity environment, earth-ground support is possible with superconducting electromagnets.

  17. New airfoils for small horizontal axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Giguere, P.; Selig, M.S. [Univ. of Illinois, Urbana, IL (United States)

    1997-12-31

    In a continuing effort to enhance the performance of small energy systems, one root airfoil and three primary airfoils were specifically designed for small horizontal axis wind turbines. These airfoils are intended primarily for 1-10 kW variable-speed wind turbines for both conventional (tapered/twisted) or pultruded blades. The four airfoils were wind-tunnel tested at Reynolds numbers between 100,000 and 500,000. Tests with simulated leading-edge roughness were also conducted. The results indicate that small variable-speed wind turbines should benefit from the use of the new airfoils which provide enhanced lift-to-drag ratio performance as compared with previously existing airfoils.

  18. Active Circulation Control for Horizontal Axis Wind Turbine

    Science.gov (United States)

    Dumitrache, Alexandru; Dumitrescu, Horia; Preotu, Octavian

    2011-09-01

    A based method for modeling the aerodynamics of horizontal axis wind turbine has been developed. Circulation control is implemented by tangentially blowing a small high-velocity jet over a highly curved surface, such as a rounded trailing edge. This causes the boundary layer and the jet sheet to remain attached along the curved surface due to the Coanda effect and causing the jet to turn without separation. This analysis has been validated for the experimental data of a rotor tested at NASA Ames Research Center. Comparisons have been done against measurements for surface pressure distribution, force coefficients normal and tangential to the chord line, torque and root bending moments. This approach for enhancing the circulation around the airfoil sections (and hence L/D and power production) has been examined and found to produce useful increases in power at low wind speeds.

  19. Computer simulation for horizontal axis wind turbine rotor optimization

    International Nuclear Information System (INIS)

    Wind turbine design is a complex process that includes multiple and conflicting criteria like maximizing energy production and minimizing the cost incurred. Often, such problems are solved using optimization techniques. A computer simulation is essential in analyzing the performance of a wind turbine rotor and determining suitable values of various design variables. The simulation will work with a design optimizer to optimize the design. In this paper, the problem of optimal rotor design is formulated and a computer simulation presented to analyze the performance of a horizontal axis wind turbine rotor of a given airfoil over a range of rotor tip speed ratios. The MATLAB simulation takes inputs of blade twist angle and chord solidity along the rotor radius as well as wind speed distribution; it provides output in the form of plots of coefficient of performance against tip speed ratio, variation of induction factors, angle of attack and coefficients of lift and drag with blade radial positions. (author)

  20. Control of dynamic stall phenomenon for vertical axis wind turbine

    Science.gov (United States)

    Frunzulicǎ, Florin; Dumitrescu, Horia; Dumitrache, Alexandru; Suatean, Bogdan

    2013-10-01

    In the last years the wind turbine with vertical axis (VAWT) began to be more attractive due benefits in exploitation, the power range covering usually the domain 2 kW-20 kW. But, VAWTs suffer from many complicated aerodynamically problems, of which dynamic stall is an inherent phenomenon when they are operating at low values of tip speed ratio (TSR VAWTs. For this reason, in the present work we perform a computational investigation of a two-dimensional dynamic stall phenomenon around a NACA0012 airfoil in oscillating motion at relative low Reynolds number (˜105). The unsteady flow is investigated numerically using RANS approach with two turbulence models (k-ω SST and transition SST). The same analysis was performed to evaluate three flow control methods: two passive and one active.

  1. Installation of cold neutron triple-axis spectrometer at HANARO

    International Nuclear Information System (INIS)

    This paper presents a recent installation of a cold neutron triple-axis spectrometer (Cold TAS) at the 30 MW HANARO research reactor at the Korea Atomic Energy Research Institute (KAERI). Because of the importance of neutron science, a cold neutron facility construction project had been started in July 2003 and was finished in 2010. The Cold TAS was primary installed at HANARO during the project. After primary installation, some technical problems had been occurred, Cold TAS improvement was initiated in 2013. The basic design of the Cold TAS was inspired by other triple-axis spectrometers, but was modified slightly to improve reliability and efficiency of the instrument. Some features of the instrument are (a) access to a high-flux neutron beam with a neutron velocity selector (NVS) as a high order filter (HOF), which can also increase the signal-to-noise ratio by eliminating neutrons of the wrong wavelength upstream of the monochromator, (b) a custom tailored and efficient electronics control system with the SPICE interface, and (c) an in-house design and fabrication of a compact single-unit multi-analyzer and detector shielding body system that surrounds an array of pyrolytic graphite (PG) crystals. The Cold TAS was also developed to be flexible enough to facilitate different experimental resolutions and requirements. In its present setup, the instrument is capable of measuring the momentum and energy transferred to the sample in a range physically accessible by the spectrometer and is expected to help instrument users perform sophisticated experiments for future studies of the dynamic energy landscape in strongly-correlated electronic materials.

  2. Specification of anteroposterior axis by combinatorial signaling during Xenopus development.

    Science.gov (United States)

    Carron, Clémence; Shi, De-Li

    2016-01-01

    The specification of anteroposterior (AP) axis is a fundamental and complex patterning process that sets up the embryonic polarity and shapes a multicellular organism. This process involves the integration of distinct signaling pathways to coordinate temporal-spatial gene expression and morphogenetic movements. In the frog Xenopus, extensive embryological and molecular studies have provided major advance in understanding the mechanism implicated in AP patterning. Following fertilization, cortical rotation leads to the transport of maternal determinants to the dorsal region and creates the primary dorsoventral (DV) asymmetry. The activation of maternal Wnt/ß-catenin signaling and a high Nodal signal induces the formation of the Nieuwkoop center in the dorsal-vegetal cells, which then triggers the formation of the Spemann organizer in the overlying dorsal marginal zone. It is now well established that the Spemann organizer plays a central role in building the vertebrate body axes because it provides patterning information for both DV and AP polarities. The antagonistic interactions between signals secreted in the Spemann organizer and the opposite ventral region pattern the mesoderm along the DV axis, and this DV information is translated into AP positional values during gastrulation. The formation of anterior neural tissue requires simultaneous inhibition of zygotic Wnt and bone morphogenetic protein (BMP) signals, while an endogenous gradient of Wnt, fibroblast growth factors (FGFs), retinoic acid (RA) signaling, and collinearly expressed Hox genes patterns the trunk and posterior regions. Collectively, DV asymmetry is mostly coupled to AP polarity, and cell-cell interactions mediated essentially by the same regulatory networks operate in DV and AP patterning. For further resources related to this article, please visit the WIREs website. PMID:26544673

  3. Thyroid axis activity and suicidal behavior in depressed patients.

    Science.gov (United States)

    Duval, Fabrice; Mokrani, Marie-Claude; Lopera, Felix Gonzalez; Diep, Thanh Son; Rabia, Hassen; Fattah, Saïd

    2010-08-01

    The aim of this study was to investigate the relationship between suicidal behavior and hypothalamic-pituitary thyroid (HPT) axis activity in depressed patients. The serum levels of thyrotropin (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were evaluated before and after 0800 and 2300 h thyrotropin-releasing hormone (TRH) challenges, on the same day, in 95 medication-free DSM-IV euthyroid major depressed inpatients and 44 healthy hospitalized controls. Compared to controls: (1) patients with a positive suicide history (PSH; n=53) showed lower basal FT4 (at 0800 h: p<0.005; at 2300 h: p<0.03), but normal FT3 levels, while patients with a negative suicide history (NSH; n=42) showed normal FT4 and FT3 levels; (2) TSH responses to TRH (DeltaTSH) were blunted in NSHs (at 0800 h: p<0.03; at 2300 h: p<0.00001), but not in PSHs; (3) both NSHs and PSHs showed lower DeltaDeltaTSH values (differences between 2300 h-DeltaTSH and 0800 h-DeltaTSH) (p<0.000001 and p<0.003, respectively). Compared to NSHs, basal FT4 levels were reduced in PSHs (at 0800 h: p<0.002; at 2300h: p<0.006). HPT parameters were not significantly different between recent suicide attempters (n=32) and past suicide attempters (n=21). However, compared to controls, recent suicide attempters showed lower 2300 h-DeltaTSH (p<0.04) and DeltaDeltaTSH (p<0.002) values, and lower basal FT4 values (at 0800 h: p<0.006; at 2300 h: p<0.02). Our results, obtained in a large sample of depressed inpatients, indicate that various degrees of HPT axis dysregulation are associated with the history of suicide. PMID:20129737

  4. IR Spectrometer Using 90-Degree Off-Axis Parabolic Mirrors

    International Nuclear Information System (INIS)

    A gated spectrometer has been designed for real-time, pulsed infrared (IR) studies at the National Synchrotron Light Source at the Brookhaven National Laboratory. A pair of 90-degree, off-axis parabolic mirrors are used to relay the light from an entrance slit to an output recording camera. With an initial wavelength range of 1500-4500 nm required, gratings could not be used in the spectrometer because grating orders would overlap. A magnesium oxide prism, placed between these parabolic mirrors, serves as the dispersion element. The spectrometer is doubly telecentric. With proper choice of the air spacing between the prism and the second parabolic mirror, any spectral region of interest within the InSb camera array's sensitivity region can be recorded. The wavelengths leaving the second parabolic mirror are collimated, thereby relaxing the camera positioning tolerance. To set up the instrument, two different wavelength (visible) lasers are introduced at the entrance slit and made collinear with the optical axis via flip mirrors. After dispersion by the prism, these two laser beams are directed to tick marks located on the outside housing of the gated IR camera. This provides first-order wavelength calibration for the instrument. Light that is reflected off the front prism face is coupled into a high-speed detector to verify steady radiance during the gated spectral imaging. Alignment features include tick marks on the prism and parabolic mirrors. This instrument was designed to complement single-point pyrometry, which provides continuous time histories of a small collection of spots from shock-heated targets

  5. Brain-Pituitary Axis Development In The CEBAS Minimodule

    Science.gov (United States)

    Schreibman, Martin P.; Magliulo-Cepriano, Lucia

    2001-01-01

    The CEBAS minimodule system is a man-made aquatic ecological system that incorporates animals, plants, snails, and microorganisms. It has been proposed that CEBAS will lead to a multigenerational experimental facility for utilization in a space station as well as for the development of an aquatic CELSS to produce animal and plant biomass for human nutrition. In this context, research on the reproductive biology of the organisms within the system should receive the highest priority. 1bus, the goals of our proposal were to provide information on space-flight-induced changes in the brain-pituitary axis and in the organs that receive information from the environment in the vertebrate selected for the CEBAS Minimodule program, the freshwater teleost Xiphophorus helleri (the swordtail). We studied the development of the brain- pituitary axis in neonates, immature and mature swordtails using histology, cytology, immunohistochemistry, morphometry, and in situ histochemistry to evaluate the synthesis, storage, and release of neurotransmitters, neuroregulatory peptides, neurohormones, and pituitary hormones as well as the structure of the organs and cells that produce, store, or are the target organs for these substances. We flew experiments in the CEBAS-minimodule on two shuttle missions, STS-89 and STS-90. In both flights four gravid females and about 200 juvenile (7 days old) swordtails (Xiphophorus helleri) constituted the aquatic vertebrates to be studied, in addition to the plants and snails that were studied by other team members. In a sample sharing agreement developed with Dr. Volker Bluem, organizer of the CEBAS research program, we received a small number of the juveniles and shared the brains of two adult females.

  6. Large Eddy Simulation of Vertical Axis Wind Turbine Wakes

    Science.gov (United States)

    Shamsoddin, Sina; Porté-Agel, Fernando

    2014-05-01

    In this study, large-eddy simulation (LES) is combined with a turbine model to investigate the wake behind a vertical-axis wind turbine (VAWT) in a three dimensional turbulent flow. Two methods are used to model the subgrid-scale (SGS) stresses: (a) the Smagorinsky model, and (b) the modulated gradient model. To parameterize the effects of the VAWT on the flow, two VAWT models are developed: (a) the actuator surface model (ASM), in which the time-averaged turbine-induced forces are distributed on a surface swept by the turbine blades, i.e. the actuator surface, and (b) the actuator line model (ALM), in which the instantaneous blade forces are only spatially distributed on lines representing the blades, i.e. the actuator lines. This is the first time that LES is applied and validated for simulation of VAWT wakes by using either the ASM or the ALM techniques. In both models, blade-element theory is used to calculate the lift and drag forces on the blades. The results are compared with flow measurements in the wake of a model straight-bladed VAWT, carried out in the Institute de Méchanique et Statistique de la Turbulence (IMST) water channel. Different combinations of SGS models with VAWT models are studied and a fairly good overall agreement between simulation results and measurement data is observed. In general, the ALM is found to better capture the unsteady-periodic nature of the wake and shows a better agreement with the experimental data compared with the ASM. The modulated gradient model is also found to be a more reliable SGS stress modeling technique, compared with the Smagorinsky model, and it yields reasonable predictions of the mean flow and turbulence characteristics of a VAWT wake using its theoretically-determined model coefficient. Keywords: Vertical-axis wind turbines (VAWTs); VAWT wake; Large-eddy simulation; Actuator surface model; Actuator line model; Smagorinsky model; Modulated gradient model

  7. Robust adaptive spin-axis stabilization of a symmetric spacecraft using two bounded torques

    Science.gov (United States)

    Gui, Haichao; Vukovich, George

    2015-12-01

    The spin-axis stabilization of an axisymmetric spacecraft by two control torques perpendicular to the symmetry axis is addressed. Two control laws are designed to align the symmetry axis along a desired inertial direction despite the revolution around the symmetry axis. The first controller takes a saturated proportional-derivative form and can stabilize the spin-axis to the desired direction with a priori bounded torques in the absence of modeling uncertainties. In order to achieve better robustness, an adaptive controller is then designed to account for the inertia uncertainties and disturbances, in addition to actuator saturation. Numerical examples are presented to demonstrate the advantageous features of the proposed algorithm compared with conventional spin-axis stabilization methods.

  8. Deflecting Easy-axis of Fe304 Single Crystal Nanowires by Magnetic-field-induced Method

    Institute of Scientific and Technical Information of China (English)

    W. Wang; S. Y. Wang

    2012-01-01

    In order to control the orientation of easy-axis of magnetic nanowires, FesO4 single crystal nanowires with easy-axis perpendicular to wire-axis were prepared successfully by means of a magnetic-field-induced method. Analysis of X-ray diffraction and electron diffraction pattern showed that there was a wide-angle deflection of easy-axis in the prepared Fe304 nanowires. A high saturation magnetization (82 emu/g) of the FesO4 nanowires was achieved at room temperature. The benefits and mechanism of the deflection of easy-axis from its wire-axis in FesO4 single crystal nanowires were discussed. The results are expected to broaden the magnetic properties of traditional ferrite nanowires.

  9. Intracerebroventricular leptin injection affects neuroendocrine reproductive axis in ovariectomized rats

    Institute of Scientific and Technical Information of China (English)

    Yuebing Qiao; Huixian Cui

    2008-01-01

    BACKGROUND: Leptin regulates neuroendocrine function of the hypothalamus-pituitary-ovary axis in humans.OBJECTIVE: To verify effects of intracerebroventricular leptin injection on neuroendocrine function of the hypothalamus-pituitary-ovary axis in nvariectomized rats.DESIGN, TIME AND SETTING: A randomized, controlled experiment was performed at the Basic Medical Institute, Chengde Medical College between June and October 2007.MATERIALS: Thirty healthy, female, Wistar rats were included in this study. The following compounds were used: leptin; gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH) enzyme-linked immunosorbent assay kits.METHODS: Rats were randomly divided into 3 groups at 1, 2, and 4 hours after injection. Each group was subdivided into control and experimental groups (n = 5 animals per group and time point). All rats were subjected to bilateral ovariectomy and, beginning on day 7 after surgery, animals received daily subcutaneous injections of estradiol benzoate (2 μ g) for 7 consecutive days. The experimental groups were injected with 5 μ L leptin (1 g/L) into the lateral cerebral ventricle, and control groups received an equal volume of physiological saline.MAIN OUTCOME MEASURES: GnRH and LH secretion were examined 1, 2, and 4 hours after injection using GnRH and LH ELISA kits, respectively.RESULTS: In the experimental groups, GnRH secretion significantly increased (P < 0.01), followed by LH secretion (P < 0.01), compared with the control groups. GnRH secretion significantly increased l hour after leptin injection (P < 0.01). The LH increase was less pronounced, but still significant (P < 0.01); however,the most prominent LH increase occurred between 1 and 2 hours. Both GnRH and LH secretion reached peak levels at 2 hours after leptin injection. Thereafter, both GnRH and LH secretion decreased, but still maintained very high levels, compared with the control group (P < 0.01).CONCLUSION: lntracerebroventricular leptin injection

  10. Analisis Semiotika Makna Pesan pada Iklan Axis Versi “Iritologi – Menatap Masa Depan”

    OpenAIRE

    Puri Sulistiyawati

    2016-01-01

    Abstrak Tujuan dari penelitian ini adalah untuk mengetahui dan menganalisis makna pesan dalam iklan Axis versi “Iritologi – Menatap masa depan” di televisi dengan menggunakan pendekatan semiotika Roland Barthes. Dari analisis yang telah dilakukan berdasarkan makna denotasi, konotasi dan mitos dalam iklan Axis versi “iritologi – Menatap masa depan”, dapat diketahui bahwa iklan Axis memiliki konsep yang sangat sederhana, dengan mengusung tema tentang kebiasaan remaja dalam memanfaatkan media s...

  11. Electromechanical three-axis development for remote handling in the Hot Experimental Facility

    International Nuclear Information System (INIS)

    A three-axis closed-loop position control system has been designed and installed on an overhead bridge, carriage, tube hoist for automotive positioning of manipulation at a remotely maintained work site. The system provides accurate (within 3 min) and repeatable three-axis positioning of the manipulator. The position control system has been interfaced to a supervisory minicomputer system that provides teach-playback capability of manipulator positioning and color graphic display of the three-axis system position

  12. OPTIMISE - Deliverable D4.3 Report on two axis rolling, month 12

    DEFF Research Database (Denmark)

    Eriksen, Morten

    This report is one of two reports which describe de deliverables on two axis rolling in the OPTIMISE project. Most of the work in this report has also been described in the sub work package reports produced during the project. The sub work package reports are WP4.1 Two axis rolling and WP4.3 Fini...... Element Modelling of two axis rolling....

  13. Charged current disappearance measurements in the NuMI off-axis beam

    Energy Technology Data Exchange (ETDEWEB)

    R. H. Bernstein

    2003-09-25

    This article studies the potential of combining charged-current disappearance measurements of {nu}{sub {mu}} {yields} {nu}{sub {tau}} from MINOS and an off-axis beam. The author finds that the error on {Delta}m{sup 2} from a 100 kt-yr off-axis measurement is a few percent of itself. Further, the author found little improvement to an off-axis measurement by combining it with MINOS.

  14. A potential field approach for collision avoidance in 5-axis milling

    OpenAIRE

    Lacharnay, Virgile; Tournier, Christophe; Pechard, Pierre-Yves; Lartigue, Claire

    2013-01-01

    Introduction 5-axis surface machining is an essential process in the field of aerospace, molds and dies industries. 5-axis milling is required for the realization of difficult parts such as blades and impellers and is also very convenientto improve quality for the machining of deep molds in plastic injection and casting by reducing tool length. Despite the evolution of CAM software, 5-axis tool path programming requires advanced skills and collision detection remains a challenge during the to...

  15. Suppression of the HPA Axis Stress-Response: Implications for Relapse

    OpenAIRE

    Adinoff, Bryon; Junghanns, Klaus; Kiefer, Falk; Krishnan-Sarin, Suchitra

    2005-01-01

    This article presents the proceedings of a symposium held at the meeting of the International Society for Biomedical Research on Alcoholism (ISBRA) in Mannheim, Germany, in October 2004. This symposium explored the potential role of hypothalamic-pituitary-adrenal (HPA) axis dysregulation upon relapse. HPA axis stimulation induces the release of the glucocorticoid cortisol, a compound with profound effects upon behavior and emotion. Altered stress-responses of the HPA axis in abstinent alcohol...

  16. Research on pattern recognition for marine steam turbine rotor axis orbit

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; YANG Zhi-da; XIA Hong

    2003-01-01

    The structure,function and recognition method of an axis orbit auto-recognizing system are presented in this paper.In order to make the best use of information of format and dynamic characteristics of marine steam turbine axis orbit,the structure and functions or neural network are applied to this system,which can be used to auto-recognize axis orbit of the system turbine rotor using BP neural network.

  17. THE MICROBIOTA-GUT-BRAIN AXIS. A STUDY IN ZEBRAFISH (DANIO RERIO)

    OpenAIRE

    Borrelli, Luca

    2015-01-01

    The microbiota is essential in the host's physiology, development, reproduction, immune system, nutrient metabolism, in brain chemistry and behavior. The gut microbiota plays a crucial role in the bidirectional gut–brain axis, a communication that integrates the gut and central nervous system (CNS) activities, and thus, the concept of microbiota–gut–brain axis is emerging where the microbes have considered as signaling components in the gut-brain axis. Animal studies reveals, in particular, t...

  18. Modelling and dynamic analysis of a semi-submersible floating vertical axis wind turbine

    OpenAIRE

    Wang, Kai

    2015-01-01

    Wind turbines are mainly classified into horizontal axis wind turbines (HAWTs) and vertical axis wind turbines (VAWTs) based on different orientation of their axis of rotation. Ever-increasing demand for energy boosts the application of the wind turbines in the deep water. The applications of HAWTs in deep water using different floating support structures have led to an increasing and versatile research due to their commercial success. However, the application of the VAWTs in t...

  19. Rapid fabrication of miniature lens arrays by four-axis single point diamond machining

    OpenAIRE

    McCall, Brian; Tkaczyk, Tomasz S.

    2013-01-01

    A novel method for fabricating lens arrays and other non-rotationally symmetric free-form optics is presented. This is a diamond machining technique using 4 controlled axes of motion – X, Y, Z, and C. As in 3-axis diamond micro-milling, a diamond ball endmill is mounted to the work spindle of a 4-axis ultra-precision computer numerical control (CNC) machine. Unlike 3-axis micro-milling, the C-axis is used to hold the cutting edge of the tool in contact with the lens surface for the entire cut...

  20. Research on calibration method of axis-shift multi-camera for aerial photogrammetry

    Science.gov (United States)

    Wang, Xiao; Fang, Junyong; Ma, Jingyu; Zhang, Xiaohong; Zhao, Dong; Liu, Xue

    2015-12-01

    Axis-shift multi-camera has been gradually applied in the aerial photogrammetry because of its advantages on structure design. In this paper, the basic axis-shift theory is analyzed, and an improved calibration method is described. A prototype system, including two axis-shift cameras, is developed to validate the feasibility and correctness of the proposed method. With the help of a high-precision indoor control field, the parameters of single camera and the relative orientation parameters of the dual camera system are calculated respectively. Experiment result indicates that this calibration method is suitable for the axis-shift multi camera system.

  1. Research on process technology of off-axis ellipsoid aspheric mirror

    Science.gov (United States)

    Liu, Dongmei; Ma, Ke; Jia, Zonghe

    2015-02-01

    In recent years, the off-axis aspheric surface is widely used in wide coverage and high-resolution space optical systems. In this paper, research on processing technology of high precision and high efficiency off-axis ellipsoid aspheric mirror was studied deeply. With the help of CNC milling and polishing machine, off-axis ellipsoid aspheric mirror with diameter of 58mm was developed, by optimizing the concentration of polish liquid, grinding size, machining direction and other process parameters, based on the disadvantage of traditional processing that off-axis aspheric is easy to generate edge splitting and secondary surface damage, a new processing method "vertical off-axis ellipsoid aspheric surface processing method" was put forward. This method not only ensures the accuracy of work piece of optical axis, surface accuracy and accuracy of the edge, but also reduces secondary surface damage, improves processing efficiency and achieves high precision and high efficiency processing of off-axis ellipsoid aspheric surface, which is conducive to mass production. Through the detection of off-axis ellipsoid aspheric mirror by Taylor Profiler , surface accuracy (PV value) is 0.1981μm, the aspheric surface finish is level II and the optical axis accuracy is 0.01mm that it meets the requirements.

  2. Analisis Semiotika Makna Pesan pada Iklan Axis Versi “Iritologi – Menatap Masa Depan”

    Directory of Open Access Journals (Sweden)

    Puri Sulistiyawati

    2016-02-01

    Full Text Available Abstrak Tujuan dari penelitian ini adalah untuk mengetahui dan menganalisis makna pesan dalam iklan Axis versi “Iritologi – Menatap masa depan” di televisi dengan menggunakan pendekatan semiotika Roland Barthes. Dari analisis yang telah dilakukan berdasarkan makna denotasi, konotasi dan mitos dalam iklan Axis versi “iritologi – Menatap masa depan”, dapat diketahui bahwa iklan Axis memiliki konsep yang sangat sederhana, dengan mengusung tema tentang kebiasaan remaja dalam memanfaatkan media sosial. Dari visual iklan yang ditampilkan menguatkan pesan bahwa produk Axis ini menyasar remaja sebagai target audience, remaja atau pelajar adalah konsumen yang mendambakan produk dengan kalitas baik namun dengan harga yang terjangkau. Meski menyasar remaja, namun dalam target marketnya Axis tetap menyasar semua kalangan. Setting tempat atau latar pada iklan yang ditampilkan pun sebagai representasi bahwa Axis dapat dijangkau oleh semua kalangan ekonomi khususnya masyarakat menengah kebawah. Makna Mitos dalam iklan Axis ini tersirat pada scene tertentu. Secara umum iklan ini menyampaikan bahwa selfie dan media sosial sebagai bagian dari kehidupan masyaraka khususnya generasi muda, sebagai sarana untuk berinteraksi dan menunjukan eksistensinya kepada komunitas. Melalui foto yang diunggah pada media sosial, khalayak merepresentasikan perasaan maupun kegiatan yang sedang di lakukannya. Sehingga hal tersebut memicu kebutuhan akan jaringan komunikasi yang lancar dan ekonomis. Kata Kunci: iklan, axis, semiotika, mitos  Abstract The purpose of this research was to determine and analyze the meaning of message in Axis advertisement version “Iritologi – Menatap masa depan” on television using Roland Barthes semiotic approach. Analysis has been done based on the meaning of denotation, connotation and myth in Axis advertisement version “Iritologi – Menatap masa depan”, it can be seen that Axis advertisement has a simple concept, with a theme of

  3. Optimization of elliptic neutron guides for triple-axis spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Janoschek, M., E-mail: mjanoschek@physics.ucsd.ed [II. Physikalisches Institut, Universitaet zu Koeln, D-50937 Koeln (Germany); Physik Department E21, Technische Universitaet Muenchen, D-85748 Garching (Germany); Boeni, P., E-mail: peter.boeni@frm2.tum.d [Physik Department E21, Technische Universitaet Muenchen, D-85748 Garching (Germany); Braden, M., E-mail: braden@ph2.uni-koeln.d [II. Physikalisches Institut, Universitaet zu Koeln, D-50937 Koeln (Germany)

    2010-01-21

    In the last decade the performance of neutron guides for the transport of neutrons has been significantly increased. The most recent developments have shown that elliptic guide systems can be used to focus neutron beams while simultaneously reducing the number of neutron reflections, hence, leading to considerable gains in neutron flux. We have carried out Monte-Carlo simulations for a new triple-axis spectrometer that will be built at the end position of the conventional cold guide NL-1 in the neutron guide hall of the research reactor FRM-II in Munich, Germany. Our results demonstrate that an elliptic guide section at the end of a conventional guide can be used to at least maintain the total neutron flux onto the sample, while significantly improving the energy resolution of the spectrometer. The simulation further allows detailed insight how the defining parameters of an elliptic guide have to be chosen to obtain optimum results. Finally, we show that the elliptic guide limits losses in the neutron flux that generally arise at the gaps, where the monochromator system of the upstream instrument is situated.

  4. Magnetic resonance imaging of hypothalamus hypophysis axis lesions

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) using a 0.5T superconductive machine was performed to the thirty three cases with a variety of the sellar and parasellar tumors and with dysfunction of the hypothalamus-hypophysis axis. Posterior pituitary bright spot (PBS) on T1 weighted image was evaluated with the pituitary hormonal function. These cases were 12 cases of post-treated tumors including pituitary adenoma (9 patients), suprasellar germinoma (2 patients) and craniopharyngioma (one patient), and non-tumorous conditions including 15 cases of central diabetes insipidus (DI), Syndrome of inappropriate secretion of ADH (SIADH) (one patient), Sheehan's syndrome (3 patients) and anorexia nervosa (2 patients). Pituitary bright spot was not seen in all 19 cases with overt DI. On the other hand, PBS was not seen in 9 cases without overt DI. Three cases of these 9 cases showing Sheehan's syndrome with insufficient antidiuretic hormone (ADH) secretion was considered as the state of subclinical DI. Posterior bright spot was not seen in all 13 cases of empty sella including partial empty sella. The results suggested that disappearance of PBS represents abnormality or loss of posterior pituitary function and also it was considered to be closely related to the empty sella. (author)

  5. Optical axis jitter rejection for double overlapped adaptive optics systems

    Science.gov (United States)

    Luo, Qi; Luo, Xi; Li, Xinyang

    2016-04-01

    Optical axis jitters, or vibrations, which arise from wind shaking and structural oscillations of optical platforms, etc., cause a deleterious impact on the performance of adaptive optics systems. When conventional integrators are utilized to reject such high frequency and narrow-band disturbance, the benefits are quite small despite their acceptable capabilities to reject atmospheric turbulence. In our case, two suits of complete adaptive optics systems called double overlapped adaptive optics systems (DOAOS) are used to counteract both optical jitters and atmospheric turbulence. A novel algorithm aiming to remove vibrations is proposed by resorting to combine the Smith predictor and notch filer. With the help of loop shaping method, the algorithm will lead to an effective and stable controller, which makes the characteristics of error transfer function close to notch filters. On the basis of the spectral analysis of observed data, the peak frequency and bandwidth of vibrations can be identified in advance. Afterwards, the number of notch filters and their parameters will be determined using coordination descending method. The relationship between controller parameters and filtering features is discussed, and the robustness of the controller against varying parameters of the control object is investigated. Preliminary experiments are carried out to validate the proposed algorithms. The overall control performance of DOAOS is simulated. Results show that time delays are a limit of the performance, but the algorithm can be successfully implemented on our systems, which indicate that it has a great potential to reject jitters.

  6. 3D CFD Analysis of a Vertical Axis Wind Turbine

    Directory of Open Access Journals (Sweden)

    Andrea Alaimo

    2015-04-01

    Full Text Available To analyze the complex and unsteady aerodynamic flow associated with wind turbine functioning, computational fluid dynamics (CFD is an attractive and powerful method. In this work, the influence of different numerical aspects on the accuracy of simulating a rotating wind turbine is studied. In particular, the effects of mesh size and structure, time step and rotational velocity have been taken into account for simulation of different wind turbine geometries. The applicative goal of this study is the comparison of the performance between a straight blade vertical axis wind turbine and a helical blade one. Analyses are carried out through the use of computational fluid dynamic ANSYS® Fluent® software, solving the Reynolds averaged Navier–Stokes (RANS equations. At first, two-dimensional simulations are used in a preliminary setup of the numerical procedure and to compute approximated performance parameters, namely the torque, power, lift and drag coefficients. Then, three-dimensional simulations are carried out with the aim of an accurate determination of the differences in the complex aerodynamic flow associated with the straight and the helical blade turbines. Static and dynamic results are then reported for different values of rotational speed.

  7. Hydroelastic dynamic characteristics of a slender axis-symmetric body

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The slender axis-symmetric submarine body moving in the vertical plane is the object of our investigation.A coupling model is developed where displacements of a solid body as a Euler beam(consisting of rigid motions and elastic deformations) and fluid pressures are employed as basic independent variables,including the interaction between hydrodynamic forces and structure dynamic forces.Firstly the hydrodynamic forces,depending on and conversely influencing body motions,are taken into account as the governing equations.The expressions of fluid pressure are derived based on the potential theory.The characteristics of fluid pressure,including its components,distribution and effect on structure dynamics,are analyzed.Then the coupling model is solved numerically by means of a finite element method(FEM).This avoids the complicacy,combining CFD(fluid) and FEM(structure),of direct numerical simulation,and allows the body with a non-strict ideal shape so as to be more suitable for practical engineering.An illustrative example is given in which the hydroelastic dynamic characteristics,natural frequencies and modes of a submarine body are analyzed and compared with experimental results.Satisfactory agreement is observed and the model presented in this paper is shown to be valid.

  8. Multi axis differential optical absorption spectroscopy (MAX-DOAS

    Directory of Open Access Journals (Sweden)

    G. Hönninger

    2004-01-01

    Full Text Available Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS in the atmosphere is a novel measurement technique that represents a significant advance on the well-established zenith scattered sunlight DOAS instruments which are mainly sensitive to stratospheric absorbers. MAX-DOAS utilizes scattered sunlight received from multiple viewing directions. The spatial distribution of various trace gases close to the instrument can be derived by combining several viewing directions. Ground based MAX-DOAS is highly sensitive to absorbers in the lowest few kilometres of the atmosphere and vertical profile information can be retrieved by combining the measurements with Radiative Transfer Model (RTM calculations. The potential of the technique for a wide variety of studies of tropospheric trace species and its (few limitations are discussed. A Monte Carlo RTM is applied to calculate Airmass Factors (AMF for the various viewing geometries of MAX-DOAS. Airmass Factors can be used to quantify the light path length within the absorber layers. The airmass factor dependencies on the viewing direction and the influence of several parameters (trace gas profile, ground albedo, aerosol profile and type, solar zenith and azimuth angles are investigated. In addition we give a brief description of the instrumental MAX-DOAS systems realised and deployed so far. The results of the RTM studies are compared to several examples of recent MAX-DOAS field experiments and an outlook for future possible applications is given.

  9. A broadband two axis flux-gate magnetometer

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1998-06-01

    Full Text Available A broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.

  10. GAMMA-RAY BURSTS ARE OBSERVED OFF-AXIS

    International Nuclear Information System (INIS)

    We constrain the jet opening angle and, for the first time, the off-axis observer angle for gamma-ray bursts in the Swift-XRT catalog by using the ScaleFit package to fit afterglow light curves directly to hydrodynamic simulations. The ScaleFit model uses scaling relations in the hydrodynamic and radiation equations to compute synthetic light curves directly from a set of high-resolution two-dimensional relativistic blast wave simulations. The data sample consists of all Swift-XRT afterglows from 2005 to 2012 with sufficient coverage and a known redshift, 226 bursts in total. We find that the jet half-opening angle varies widely but is commonly less than 0.1 rad. The distribution of the electron spectral index is also broad, with a median at 2.30. We find the observer angle to have a median value of 0.57 of the jet opening angle over our sample, which has profound consequences for the predicted rate of observed jet breaks and affects the beaming-corrected total energies of gamma-ray bursts

  11. EUV off-axis focusing using a high harmonic source

    Science.gov (United States)

    Mills, B.; Rogers, E. T. F.; Grant-Jacob, J.; Stebbings, S. L.; Praeger, M.; de Paula, A. M.; Froud, C. A.; Chapman, R. T.; Butcher, T. J.; Brocklesby, W. S.; Frey, J. G.

    2009-05-01

    High Harmonic Generation is a well established technique for generating Extreme Ultraviolet radiation. It is a promising technique for both structure and spectroscopic imaging due to both the high flux and coherence of the source, and the existence of multiple absorption edges at the generated wavelengths. To increase the flux, a focussing device can be used. Here we present focussing results for a Mo/Si spherical mirror that has been used in an off-axis arrangement, and give extensive analysis of the resulting astigmatic focus and its consequence on diffractive imaging. The astigmatic beam exists as a vertical and horizontal focus, separated by a circle of least confusion. With the help of a theoretical model we show that the most intense part of the beam is always the second line foci and that the phase at the focus is strongly saddle-shaped. However, this phase distortion cannot explain the significant interference peak splitting that is experimentally observed in our diffraction patterns. Instead we propose that the beam quality is degraded upon reflection from the multilayer mirror and it is this asymmetric phase distortion that causes the diffraction peak splitting.

  12. Fully off-axis ECCD driven plasmas in TCV

    International Nuclear Information System (INIS)

    Fully non-inductive plasma discharges sustained by off-axis Electron Cyclotron Current Drive (ECCD) in the TCV tokamak are reported. Steady state discharges with very good confinement properties and a large bootstrap current fraction can be created in the absence of an Ohmic field. The total current density profile is hollow owing to the bootstrap current. A steady state electron Internal Transport Barrier (eITB) is observed inside the ECCD deposition radius. Once fully formed, the eITB is efficient in that the addition of 0.45 MW central EC power causes no degradation in the confinement time. Best results are obtained with a small central counter current drive component. In this plasma HRLW = 4.5 is reported (HRLW τEe/τRLW) with bootstrap current fraction IBS/Ip = 50%. The current profile can be finely tuned at zero loop voltage, allowing operation just below the MHD instability limit. Current density profile modeling is performed with a Fokker-Planck code using a model for radial transport. The bootstrap current is calculated from Thomson profiles. (authors)

  13. Miniature horizontal axis wind turbine system for multipurpose application

    International Nuclear Information System (INIS)

    A MWT (miniature wind turbine) has received great attention recently for powering WISP (Wireless Intelligent Sensor Platform). In this study, two MHAWTs (miniature horizontal axis wind turbines) with and without gear transmission were designed and fabricated. A physics-based model was proposed and the optimal load resistances of the MHAWTs were predicted. The open circuit voltages, output powers and net efficiencies were measured under various ambient winds and load resistances. The experimental results showed the optimal load resistances matched well with the predicted results; the MHAWT without gear obtained higher output power at the wind speed of 2 m/s to 6 m/s, while the geared MHAWT exhibited better performance at the wind speed higher than 6 m/s. In addition, a DCM (discontinuous conduction mode) buck-boost converter was adopted as an interface circuit to maximize the charging power from MHAWTs to rechargeable batteries, exhibiting maximum efficiencies above 85%. The charging power reached about 8 mW and 36 mW at the wind speeds of 4 m/s and 6 m/s respectively, which indicated that the MHAWTs were capable for sufficient energy harvesting for powering low-power electronics continuously. - Highlights: • Performance of the miniature wind turbines with and without gears was compared. • The physics-based model was established and proved successfully. • The interface circuit with efficiency of more than 85% was designed

  14. The Parameters Affect on Power Coefficient Vertical Axis Wind Turbine

    Directory of Open Access Journals (Sweden)

    Ahmed Y. Qasim

    2012-04-01

    Full Text Available ABSTRACT: This study describes the design of a special type of vertical axis rotor wind turbine with moveable vertically positioned vanes. The novel design increases the torque in the left side of the wind turbine by increasing the drag coefficient. It also reduces the negative torque of the frame which rotates contrary to the wind in the other side. Two different types of models, having different vane shapes (flat vane and cavity shaped vane, were fabricated. Each type consisted of two models with varying number of frames (three and four frames. The models were tested in a wind tunnel with variable wind speed in order to understand the effect of shape, weight, and number of frames on the power coefficient of the wind turbine. ABSTRAK: Di dalam kajian ini, rotor turbin angin berpaksi vertikel sebagai rangka khusus telah direkabentuk dengan lokasi vertikel mudahalih oleh bilah kipas. Rekabentuk ini meningkatkan tork di bahagian kiri turbin angin dengan meningkatkan pekali seretan dan mengurangkan tork negatif rangka yang berputar berlawanan dengan angin pada bahagian lain. Dua jenis model berbentuk berlainan telah difabrikasi (bilah kipas rata dan bilah kipas berbentuk kaviti, dengan setiap jenis mempunyai dua model dengan bilangan rangka yang berlainan (berangka tiga dan berangka empat. Model-model telah diuji di dalam terowong angin dengan kelajuan angin yang berbeza bagi mendapatkan kesan rekabentuk, berat dan bilangan rangka ke atas pekali kuasa.KEYWORDS: design; wind turbine; drag coefficient; vane

  15. On the theory of the horizontal-axis wind turbine

    Science.gov (United States)

    de Vries, O.

    The fluid mechanical theory of horizontal axis wind turbines (HAWT) in homogeneous, steady flows is presented. HAWT aerodynamic performance is governed by rotor torque and drag, the angular velocity, and power output, with governing equations for momentum, mass, and energy. The lift force and profile drag acting on the airfoil blades depend on the flow velocity, the chord length, the angle of attack, and the lift and drag coefficients. Single streamtube and multiple-stream tube and angular momentum analyses are employed to quantify the maximum wind turbine performance. Optimization studies for HAWT blades have indicated that a considerable amount of blade twist and taper enhances HAWT performance. Blade-element and vortex theory combined with panel methods are used to study optimum blade shapes. Techniques for assuring that wind tunnel studies of scale models are valid for full scale machines are defined. Sample runs have shown the accuracy of the blade element theory and the inaccuracies of two-dimensional analyses when stall is reached. The acquisition of more aerodynamic data on HAWT performance is indicated.

  16. Aeroelastic stability and response of horizontal axis wind turbine blades

    Science.gov (United States)

    Kottapalli, S. B. R.; Friedmann, P. P.; Rosen, A.

    1979-01-01

    Coupled flap-lag-torsion equations of motion of an isolated horizontal axis wind turbine (HAWT) blade have been formulated. The analysis neglects blade-tower coupling. The final nonlinear equations have periodic coefficients. A new and convenient method of generating an appropriate time-dependent equilibrium position, required for the stability analysis, has been implemented and found to be computationally efficient. Steady-state response and stability boundaries for an existing (typical) HAWT blade are presented. Such stability boundaries have never been published in the literature. The results show that the isolated blade under study is basically stable. The tower shadow (wake) has a considerable effect on the out-of-plane response but leaves blade stability unchanged. Nonlinear terms can significantly affect linearized stability boundaries; however, they have a negligible effect on response, thus implying that a time-dependent equilibrium position (or steady-state response), based completely on the linear system, is appropriate for the type of HAWT blades under study.

  17. Numerical study on small scale vertical axis wind turbine

    Science.gov (United States)

    Parra-Santos, Teresa; Gallegos, Armando; Uzarraga, Cristóbal N.; Rodriguez, Miguel A.

    2016-03-01

    The performance of a Vertical Axis Wind Turbine (VAWT) is numerically analyzed. The set-up is Hdarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft. The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s. Influence of pitch angle is tested to get design tendencies. 2D, transient, Navier Stokes equations are solved using the code Ansys-Fluent. Conservation equations were solved with a Third-Order MUSCL scheme using SIMPLE to couple pressure and velocity. More than six revolutions must be simulated to get the periodic behavior. Two models of turbulence have been contrasted Realizable k-epsilon and Transition SST concluding the last one show more realistic flow features. Pitch angles of 0º, -6º and -10º have been tested with Tip Speed Ratios ranging from 0.7 and 1.6. The no null pitch angles improve the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are showed.

  18. Off-axis electron holography of ferromagnetic multilayer nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Akhtari-Zavareh, Azadeh; Kavanagh, K. L. [Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A1S6 (Canada); Carignan, L. P. [Apollo Microwaves, 1650 Trans-Canada Highway, Dorval, Quebec H9P 1H7 (Canada); Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Quebec, H3C 3A7 Canada (Canada); Department of Electrical Engineering, École Polytechnique de Montréal, Montréal, Quebec, H3C 3A7 Canada (Canada); Yelon, A.; Ménard, D. [Department of Engineering Physics, École Polytechnique de Montréal, Montréal, Quebec, H3C 3A7 Canada (Canada); Kasama, T. [Center for Electron Nanoscopy, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Herring, R. [Department of Mechanical Engineering, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Dunin-Borkowski, R. E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Institute for Microstructure Research, D-52425 Jülich (Germany); McCartney, M. R. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States)

    2014-07-14

    We have used electron holography to investigate the local magnetic behavior of isolated ferromagnetic nanowires (NWs) in their remanent states. The NWs consisted of periodic magnetic layers of soft, high-saturation magnetization CoFeB alloys, and non-magnetic layers of Cu. All NWs were fabricated by pulsed-potential electrodeposition in nanoporous alumina membranes. The NW composition and layer thicknesses were measured using scanning transmission electron microscopy and energy dispersive spectroscopy. The magnetization of individual NWs depended upon the thicknesses of the layers and the direction of an external magnetic field, which had been applied in situ. When the CoFeB was thicker than the diameter (50 nm), magnetization was axial for all external field directions, while thinner layers could be randomized via a perpendicular field. In some cases, magnetization inside the wire was detected at an angle with respect to the axis of the wires. In thinner Cu/CoFeB (<10 nm each) multilayer, magnetic field vortices were detected, associated with opposing magnetization in neighbouring layers. The measured crystallinity, compositions, and layer thicknesses of individual NWs were found to be significantly different from those predicted from calibration growths based on uniform composition NWs. In particular, a significant fraction of Cu (up to 50 at. %) was present in the CoFeB layers such that the measured magnetic induction was lower than expected. These results will be used to better understand previously measured effective anisotropy fields of similar NW arrays.

  19. Comparison of aerodynamic models for Vertical Axis Wind Turbines

    International Nuclear Information System (INIS)

    Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models, which explicitly model the wake as a system of vorticity, show mostly differences due to the instantaneous or time averaged formulation of the loading and flow, for which further research is needed

  20. Investigation of implementation of stators on vertical axis wind turbines

    Science.gov (United States)

    Alexander, Aaron; Santhanakrishnan, Arvind

    2014-11-01

    Vertical Axis Wind Turbines (VAWT) have historically suffered from an inability to self-start and, especially on Savonius rotors, low efficiencies due to drag on the returning blade. A few VAWT studies have examined the use of stators to direct the flow onto the power producing side of the rotor thus preventing drag on the returning side, yet all of the designs studied allow the air to exit on the downstream side of the entering flow. This study investigates an alternative stator design for extracting more wind energy by trapping the incoming flow into a rising vortex within the stator enclosure. The flow is then allowed to exit above the stator. The current study compared the performance of a generic Savonius rotor in a 7 m/s free stream flow with the same rotor in two different stator designs. The first stator design allows the flow to escape in the downstream direction. The second stator design utilizes the same stator shape, but forces the air to remain trapped until it can exit above the stators. The initial evaluation of the results was conducted using Computational Fluid Dynamics (CFD) package Star-CCM + set up with an unsteady k- ɛ model at a Reynolds number of about 1,400,000. Experimental comparisons with scale models will be presented.

  1. Off-axis signal processing of cetacean biosonar

    Science.gov (United States)

    Zimmer, Walter M. X.

    2001-05-01

    Echolocation or biosonar plays a fundamental role for odontocetes to probe their environment, and their characteristics have been studied extensively for over 40 years. In summary, cetacean biosonar can be modeled as broadband transient-like signals radiating from a finite piston or aperture. The resulting sonar beam is directional, with a directivity index exceeding 25 dB for some species. The estimation of relevant sonar parameters is usually obtained from animals that are kept within a controlled and well-instrumented environment. This paper shows how measurements of opportunity from free-ranging odontocetes may be used to obtain their relevant biosonar parameters, in particular directivity index and source level. Frequently these measurements are made with a single hydrophone that is sufficiently deep so that surface-reflected echoes separate from the direct arrival of the echolocation clicks. Also, the received signal often fades in and out as the sonar beam of the scanning animal crosses the hydrophone. The presented technique exploits this scanning and the observation that broadband signals from a finite aperture will appear distorted when recorded off the acoustic axis, as the transfer function of the aperture modifies the spectrum of the transmitted signal.

  2. The Gut-Brain Axis: The Missing Link in Depression.

    Science.gov (United States)

    Evrensel, Alper; Ceylan, Mehmet Emin

    2015-12-31

    The gut microbiota is essential to human health and the immune system and plays a major role in the bidirectional communication between the gut and the brain. Based on evidence, the gut microbiota is associated with metabolic disorders such as obesity, diabetes mellitus and neuropsychiatric disorders such as schizophrenia, autistic disorders, anxiety disorders and major depressive disorders. In the past few years, neuroscientific research has shown the importance of the microbiota in the development of brain systems. Recent studies showed that the microbiota could activate the immune and central nervous systems, including commensal and pathogenic microorganisms in the gastrointestinal tract. Gut microorganisms are capable of producing and delivering neuroactive substances such as serotonin and gamma-aminobutyric acid, which act on the gut-brain axis. Preclinical research in rodents suggested that certain probiotics have antidepressant and anxiolytic activities. Effects may be mediated via the immune system or neuroendocrine systems. Herein, we present the latest literature examining the effects of the gut microbiota on depression. PMID:26598580

  3. Physiological focus on the erythropoietin-hepcidin-ferroportin axis.

    Science.gov (United States)

    D'Anna, María Cecilia; Roque, Marta Elena

    2013-05-01

    To analyze the interconnection between erythropoiesis and iron metabolism, one of the issues raised in this study was to know iron bioavailability under physiopathological conditions. Our aim was to understand the functional axis response composed of erythropoietin (Epo)-hepcidin-ferroportin (FPN), when 2 dysfunctional states coexist, using an animal model of iron overload followed by hypoxia. FPN and prohepcidin were assessed by immunohistochemistry using rabbit anti-mouse FPN polyclonal and prohepcidin monoclonal antibodies. Goat-labeled polymer - horseradish peroxidase anti-rabbit EnVision + System (DAB) was used as the secondary antibody. Epo levels were measured by ELISA. Tissue iron was studied by Prussian blue iron staining. Erythropoietic response was assessed using conventional hematological tests. Iron overload increased prohepcidin that remained high in hypoxia, coexisting with high levels of Epo in hypoxia, with or without iron overload. In hypoxia, FPN was clearly evident in reticuloendothelial macrophages, more than in hypoxia with iron overload. Interestingly, duodenal FPN was clearly identified on the basolateral membrane in hypoxia, with or without iron overload. Our data indicate that 2 signals could induce the cell-specific response as follows: (i) iron signal, induced prohepcidin, which reduced reticuloendothelial FPN and reduced iron availability; and (ii) hypoxia signal, stimulated Epo, which affected iron absorption by stabilizing duodenal FPN and allowed iron supply to erythropoiesis independently of store size. PMID:23656253

  4. MRI of the hypothalamic-pituitary axis in children

    Energy Technology Data Exchange (ETDEWEB)

    Argyropoulou, Maria I. [University of Ioannina, Department of Radiology, Medical School, Ioannina (Greece); Kiortsis, Dimitrios Nikiforos [University of Ioannina, Department of Physiology, Medical School, Ioannina (Greece)

    2005-11-01

    In childhood, the MR characteristics of the normal pituitary gland are well established. During the first 2 months of life the adenohypophysis demonstrates high signal. Pituitary gland height (PGH) decreases during the 1st year of life and then increases, reaching a plateau after puberty. The magnetization transfer ratio (MTR) increases in both sexes up to the age of 20 years. On dynamic contrast-enhanced studies, the posterior pituitary lobe enhances simultaneously with the straight sinus, and the adenohypophysis later, but within 30 s. In genetically determined dysfunctional states, the adenohypophysis may be normal, hypoplastic, or enlarged. Pituitary enlargement, observed in Prop 1 gene mutations, is characterized by a mass interposed between the anterior and posterior lobes. An ectopic posterior lobe (EPP), associated with a hypoplastic or absent pituitary stalk, may be observed in patients with hypopituitarism. Tumors of the hypothalamic-pituitary (HP) axis may be the origin of adenohypophyseal deficiencies. A small hypointense adenohypophysis is found in iron overload states and is often associated with hypogonadotrophic hypogonadism. Absence of the posterior lobe bright signal, with or without a thick pituitary stalk or a mass at any site from the median eminence to the posterior pituitary lobe, may be found in diabetes insipidus. Hydrocephalus, suprasellar arachnoid cysts, hypothalamic hamartomas and craniopharyngiomas may result in central precocious puberty (CPP). Increased PGH in girls with idiopathic CPP is useful for its differential diagnosis from premature thelarche (PT). Pituitary adenomas, observed mainly in adolescents, present the same MR characteristics as those in adults. (orig.)

  5. Design of h-Darrieus vertical axis wind turbine

    Science.gov (United States)

    Parra, Teresa; Vega, Carmen; Gallegos, A.; Uzarraga, N. C.; Castro, F.

    2015-05-01

    Numerical simulation is used to predict the performance of a Vertical Axis Wind Turbine (VAWT) H-Darrieus. The rotor consists of three straight blades with shape of aerofoil of the NACA family attached to a rotating vertical shaft. The influence of the solidity is tested to get design tendencies. The mesh has two fluid volumes: one sliding mesh for the rotor where the rotation velocity is established while the other is the environment of the rotor. Bearing in mind the overall flow is characterized by important secondary flows, the turbulence model selected was realizable k-epsilon with non-equilibrium wall functions. Conservation equations were solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. During VAWT operation, the performance depends mainly on the relative motion of the rotating blade and has a fundamental period which depends both on the rate of rotation and the number of blades. The transient study is necessary to characterise the hysteresis phenomenon. Hence, more than six revolutions get the periodic behaviour. Instantaneous flows provide insight about wake structure interaction. Time averaged parameters let obtain the characteristic curves of power coefficient.

  6. Comparison of aerodynamic models for Vertical Axis Wind Turbines

    Science.gov (United States)

    Simão Ferreira, C.; Aagaard Madsen, H.; Barone, M.; Roscher, B.; Deglaire, P.; Arduin, I.

    2014-06-01

    Multi-megawatt Vertical Axis Wind Turbines (VAWTs) are experiencing an increased interest for floating offshore applications. However, VAWT development is hindered by the lack of fast, accurate and validated simulation models. This work compares six different numerical models for VAWTS: a multiple streamtube model, a double-multiple streamtube model, the actuator cylinder model, a 2D potential flow panel model, a 3D unsteady lifting line model, and a 2D conformal mapping unsteady vortex model. The comparison covers rotor configurations with two NACA0015 blades, for several tip speed ratios, rotor solidity and fixed pitch angle, included heavily loaded rotors, in inviscid flow. The results show that the streamtube models are inaccurate, and that correct predictions of rotor power and rotor thrust are an effect of error cancellation which only occurs at specific configurations. The other four models, which explicitly model the wake as a system of vorticity, show mostly differences due to the instantaneous or time averaged formulation of the loading and flow, for which further research is needed.

  7. Design of h-Darrieus vertical axis wind turbine

    Directory of Open Access Journals (Sweden)

    Parra Teresa

    2015-01-01

    Full Text Available Numerical simulation is used to predict the performance of a Vertical Axis Wind Turbine (VAWT H-Darrieus. The rotor consists of three straight blades with shape of aerofoil of the NACA family attached to a rotating vertical shaft. The influence of the solidity is tested to get design tendencies. The mesh has two fluid volumes: one sliding mesh for the rotor where the rotation velocity is established while the other is the environment of the rotor. Bearing in mind the overall flow is characterized by important secondary flows, the turbulence model selected was realizable k-epsilon with non-equilibrium wall functions. Conservation equations were solved with a Third-Order Muscl scheme using SIMPLE to couple pressure and velocity. During VAWT operation, the performance depends mainly on the relative motion of the rotating blade and has a fundamental period which depends both on the rate of rotation and the number of blades. The transient study is necessary to characterise the hysteresis phenomenon. Hence, more than six revolutions get the periodic behaviour. Instantaneous flows provide insight about wake structure interaction. Time averaged parameters let obtain the characteristic curves of power coefficient.

  8. Morping blade design for vertical axis wind turbines

    Science.gov (United States)

    Macphee, David; Beyene, Asfaw

    2015-11-01

    Wind turbines operate at peak efficiency at a certain set of operational conditions. Away from these conditions, conversion efficiency drops significantly, requiring pitch and yaw control schemes to mitigate these losses. These efforts are an example of geometric variability, allowing for increased power production but with an unfortunate increase in investment cost to the energy conversion system. In Vertical-Axis Wind Turbines (VAWTs), the concept of pitch control is especially complicated due to a dependence of attack angle on armature azimuth. As a result, VAWT pitch control schemes, both active and passive, are as of yet unfeasible. This study investigates a low-cost, passive pitch control system, in which VAWT blades are constructed of a flexible material, allowing for continuous shape-morphing in response to local aerodynamic loading. This design is analyzed computationally using a finite-volume fluid-structure interaction routine and compared to a geometrically identical rigid rotor. The results indicate that the flexible blade increases conversion efficiency by reducing the severity of vortex shedding, allowing for greater average torque over a complete revolution.

  9. Numerical study on small scale vertical axis wind turbine

    Directory of Open Access Journals (Sweden)

    Parra-Santos Teresa

    2016-01-01

    Full Text Available The performance of a Vertical Axis Wind Turbine (VAWT is numerically analyzed. The set-up is Hdarrieus with three straight blades airfoils NACA attached to a rotating vertical shaft. The wind turbine has solidity equals to the unity operating with wind velocity of 7 m/s. Influence of pitch angle is tested to get design tendencies. 2D, transient, Navier Stokes equations are solved using the code Ansys-Fluent. Conservation equations were solved with a Third-Order MUSCL scheme using SIMPLE to couple pressure and velocity. More than six revolutions must be simulated to get the periodic behavior. Two models of turbulence have been contrasted Realizable k-epsilon and Transition SST concluding the last one show more realistic flow features. Pitch angles of 0º, -6º and -10º have been tested with Tip Speed Ratios ranging from 0.7 and 1.6. The no null pitch angles improve the performance of the wind turbine. Instantaneous and averaged power coefficients as well as detailed flow field around the airfoils are showed.

  10. Characterization of a multi-axis ion chamber array

    International Nuclear Information System (INIS)

    Purpose: The aim of this work was to characterize a multi-axis ion chamber array (IC PROFILER; Sun Nuclear Corporation, Melbourne, FL USA) that has the potential to simplify the acquisition of LINAC beam data. Methods: The IC PROFILER (or panel) measurement response was characterized with respect to radiation beam properties, including dose, dose per pulse, pulse rate frequency (PRF), and energy. Panel properties were also studied, including detector-calibration stability, power-on time, backscatter dependence, and the panel's agreement with water tank measurements [profiles, fractional depth dose (FDD), and output factors]. Results: The panel's relative deviation was typically within (±) 1% of an independent (or nominal) response for all properties that were tested. Notable results were (a) a detectable relative field shape change of ∼1% with linear accelerator PRF changes; (b) a large range in backscatter thickness had a minimal effect on the measured dose distribution (typically less than 1%); (c) the error spread in profile comparison between the panel and scanning water tank (Blue Phantom, CC13; IBA Schwarzenbruck, DE) was approximately (±) 0.75%. Conclusions: The ability of the panel to accurately reproduce water tank profiles, FDDs, and output factors is an indication of its abilities as a dosimetry system. The benefits of using the panel versus a scanning water tank are less setup time and less error susceptibility. The same measurements (including device setup and breakdown) for both systems took 180 min with the water tank versus 30 min with the panel. The time-savings increase as the measurement load is increased.

  11. Large Eddy Simulation of Vertical Axis Wind Turbine Wakes

    Directory of Open Access Journals (Sweden)

    Sina Shamsoddin

    2014-02-01

    Full Text Available In this study, large eddy simulation (LES is combined with a turbine model to investigate the wake behind a vertical-axis wind turbine (VAWT in a three-dimensional turbulent flow. Two methods are used to model the subgrid-scale (SGS stresses: (a the Smagorinsky model; and (b the modulated gradient model. To parameterize the effects of the VAWT on the flow, two VAWT models are developed: (a the actuator swept-surface model (ASSM, in which the time-averaged turbine-induced forces are distributed on a surface swept by the turbine blades, i.e., the actuator swept surface; and (b the actuator line model (ALM, in which the instantaneous blade forces are only spatially distributed on lines representing the blades, i.e., the actuator lines. This is the first time that LES has been applied and validated for the simulation of VAWT wakes by using either the ASSM or the ALM techniques. In both models, blade-element theory is used to calculate the lift and drag forces on the blades. The results are compared with flow measurements in the wake of a model straight-bladed VAWT, carried out in the Institute de Méchanique et Statistique de la Turbulence (IMST water channel. Different combinations of SGS models with VAWT models are studied, and a fairly good overall agreement between simulation results and measurement data is observed. In general, the ALM is found to better capture the unsteady-periodic nature of the wake and shows a better agreement with the experimental data compared with the ASSM. The modulated gradient model is also found to be a more reliable SGS stress modeling technique, compared with the Smagorinsky model, and it yields reasonable predictions of the mean flow and turbulence characteristics of a VAWT wake using its theoretically-determined model coefficient.

  12. 60 YEARS OF NEUROENDOCRINOLOGY: The hypothalamo-prolactin axis.

    Science.gov (United States)

    Grattan, David R

    2015-08-01

    The hypothalamic control of prolactin secretion is different from other anterior pituitary hormones, in that it is predominantly inhibitory, by means of dopamine from the tuberoinfundibular dopamine neurons. In addition, prolactin does not have an endocrine target tissue, and therefore lacks the classical feedback pathway to regulate its secretion. Instead, it is regulated by short loop feedback, whereby prolactin itself acts in the brain to stimulate production of dopamine and thereby inhibit its own secretion. Finally, despite its relatively simple name, prolactin has a broad range of functions in the body, in addition to its defining role in promoting lactation. As such, the hypothalamo-prolactin axis has many characteristics that are quite distinct from other hypothalamo-pituitary systems. This review will provide a brief overview of our current understanding of the neuroendocrine control of prolactin secretion, in particular focusing on the plasticity evident in this system, which keeps prolactin secretion at low levels most of the time, but enables extended periods of hyperprolactinemia when necessary for lactation. Key prolactin functions beyond milk production will be discussed, particularly focusing on the role of prolactin in inducing adaptive responses in multiple different systems to facilitate lactation, and the consequences if prolactin action is impaired. A feature of this pleiotropic activity is that functions that may be adaptive in the lactating state might be maladaptive if prolactin levels are elevated inappropriately. Overall, my goal is to give a flavour of both the history and current state of the field of prolactin neuroendocrinology, and identify some exciting new areas of research development. PMID:26101377

  13. Endocrine disruptors and estrogenic effects on male reproductive axis

    Institute of Scientific and Technical Information of China (English)

    Suresh C. Sikka; Run Wang

    2008-01-01

    Endocrine disruptors (e.g., polychlorinated biphenyls [PCBs], dichlorodiphenyl-trichloroethane [DDT], dioxin,and some pesticides) are estrogen-like and anti-androgenic chemicals in the environment. They mimic natural hormones,inhibit the action of hormones, or alter the normal regulatory function of the endocrine system and have potential hazardous effects on male reproductive axis causing infertility. Although testicular and prostate cancers, abnormal sexual development, undescended testis, chronic inflammation, Sertoli-cell-only pattern, hypospadias, altered pituitary and thyroid gland functions are also observed, the available data are insufficient to deduce worldwide conclusions.The development of intra-cytoplasmic sperm injection (ICSI) is beyond doubt the most important recent breakthrough in the treatment of male infertility, but it does not necessarily treat the cause and may inadvertently pass on adverse genetic consequences. Many well-controlled clinical studies and basic scientific discoveries in the physiology,biochemistry, and molecular and cellular biology of the male reproductive system have helped in the identification of greater numbers of men with male factor problems. Newer tools for the detection of Y-chromosome deletions have further strengthened the hypothesis that the decline in male reproductive health and fertility may be related to the presence of certain toxic chemicals in the environment. Thus the etiology, diagnosis, and treatment of male factor infertility remain a real challenge. Clinicians should always attempt to identify the etiology of a possible testicular toxicity, assess the degree of risk to the patient being evaluated for infertility, and initiate a plan to control and prevent exposure to others once an association between occupation/toxicant and infertility has been established.

  14. Performance testing of a small vertical-axis wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Bravo, R.; Tullis, S.; Ziada, S. [McMaster Univ., Hamilton, ON (Canada). Dept. of Mechanical Engineering

    2007-07-01

    Full-scale wind tunnel testing of a prototype 3.5 kW vertical-axis wind turbine (VAWT) was conducted in a low speed wind tunnel in Ottawa. The tests were conducted to determine nominal power curves as well as the system's structural integrity, safety and operational characteristics. Dimensionless power curves were used to assess the relation between the wind turbine's rotary speed and the produced power for various wind speeds. Tests began at the lowest wind speed and revolutions per minute (RPM) and were gradually increased. A proximity sensor was used to determine the passing frequency of spaced bolts. The aerodynamic performance of the turbine was evaluated using a servo-controlled mechanical variable load with a disc brake calliper and electro-hydraulic servo-actuator. A load cell was used to measure torque produced by the turbine. An active closed loop speed control system was used to regulate the rotary speed of the turbine. The system used a high gain proportional control law to guarantee stability. Calculated power was based on the average rotary speed measurement. Results of the study suggested that the dimensional power performance of the turbine could be predicted from the curve for all rotary speeds and for wind speeds between 8 and 16 m/s. The maximum power coefficient of 0.3 occurred at a tip speed ratio of 1.6. Test results demonstrated that the turbine reached its rated power at 14 m/s. However, the range of tip speed ratios for power production were lower than the range for most other small VAWT. 2 refs., 3 figs.

  15. Modular design and development methodology for robotic multi-axis F/M sensors

    Science.gov (United States)

    Liang, Qiao-Kang; Zhang, Dan; Coppola, Gianmarc; Wu, Wan-Neng; Zou, Kun-Lin; Wang, Yao-Nan; Sun, Wei; Ge, Yun-Jian; Ge, Yu

    2016-04-01

    Accurate Force/Moment (F/M) measurements are required in many applications, and multi-axis F/M sensors have been utilized a wide variety of robotic systems since 1970s. A multi-axis F/M sensor is capable of measuring multiple components of force terms along x-, y-, z-axis (Fx, Fy, Fz), and the moments terms about x-, y- and z-axis (Mx, My and Mz) simultaneously. In this manuscript, we describe experimental and theoretical approaches for using modular Elastic Elements (EE) to efficiently achieve multi-axis, high-performance F/M sensors. Specifically, the proposed approach employs combinations of simple modular elements (e.g. lamella and diaphragm) in monolithic constructions to develop various multi-axis F/M sensors. Models of multi-axis F/M sensors are established, and the experimental results indicate that the new approach could be widely used for development of multi-axis F/M sensors for many other different applications.

  16. Effortful Control and Parenting: Associations with HPA Axis Reactivity in Early Childhood

    Science.gov (United States)

    Kryski, Katie R.; Dougherty, Lea R.; Dyson, Margaret W.; Olino, Thomas M.; Laptook, Rebecca S.; Klein, Daniel N.; Hayden, Elizabeth P.

    2013-01-01

    While activation of the hypothalamic-pituitary-adrenal (HPA) axis is an adaptive response to stress, excessive HPA axis reactivity may be an important marker of childhood vulnerability to psychopathology. Parenting, including parent affect during parent-child interactions, may play an important role in shaping the developing HPA system; however,…

  17. Evaluation of the P Wave Axis in Patients With Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Rezzan Deniz Acar

    2015-12-01

    Conclusion: P wave axis was found significantly increased in patients with SLE and positively correlated with SELENA-SLEDAI score. As the risk score increases in patients with SLE, P wave axis changes which may predict the risk of all-cause and cardiovascular mortality.

  18. Bouncing back - trauma and the HPA-axis in healthy adults

    Directory of Open Access Journals (Sweden)

    Ellen Renée Klaassens

    2010-12-01

    Full Text Available Dysregulation of the hypothalamic–pituitary–adrenal (HPA-axis is thought to underlie stress-related psychiatric disorders such as posttraumatic stress disorder (PTSD. Some studies have reported HPA-axis dysregulation in trauma-exposed (TE adults in the absence of psychiatric morbidity. In this dissertation we set out to unravel part of the mechanism that underlies the complex relations between trauma exposure, stress regulation, and psychopathology. Mentally healthy TE subjects were compared with non-trauma-exposed (NE healthy controls. To distinguish between the potential effects of childhood trauma and adulthood trauma, we included women exposed to childhood trauma as well as men who were exposed to trauma during adulthood. Basal HPA-axis functioning was assessed with salivary cortisol samples. HPA-axis reactivity was assessed with the dexamethasone/corticotropin-releasing hormone (Dex/CRH test. The results show that childhood trauma exposure is associated with an attenuated cortisol response after the Dex/CRH challenge test in women. In contrast, trauma exposure during adulthood was not associated with alterations in HPA-axis regulation after the Dex/CRH test. Neither childhood trauma nor adulthood trauma were associated with basal HPA-axis functioning. Childhood trauma rather than adulthood trauma may chronically affect HPA-axis functioning. Since the association between adulthood trauma and resilience to psychopathology cannot be explained by HPA-axis functioning alone, other factors must play a role.

  19. Biosynthesis of intestinal microvillar proteins. Expression of aminopeptidase N along the crypt-villus axis

    DEFF Research Database (Denmark)

    Danielsen, E M

    1984-01-01

    The expression of pig small-intestinal aminopeptidase N (EC 3.4.11.2) along the crypt-villus axis was studied in tangential sections of [35S]-methionine-labelled, organ-cultured explants. The only detectable molecular forms of aminopeptidase N along the crypt-villus axis were polypeptides of Mr 140...

  20. Local Auxin Sources Orient the Apical-Basal Axis in Arabidopsis Embryos

    NARCIS (Netherlands)

    Robert, H.S.; Grones, P.; Stepanova, A.N.; Robles, L.M.; Lokerse, A.S.; Alonso, J.M.; Weijers, D.; Friml, J.

    2013-01-01

    Establishment of the embryonic axis foreshadows the main body axis of adults both in plants and in animals, but underlying mechanisms are considered distinct. Plants utilize directional, cell-to-cell transport of the growth hormone auxin [1 and 2] to generate an asymmetric auxin response that specif

  1. Kinematic equations to grind a helical drill point on a virtual axis drill sharpener

    Institute of Scientific and Technical Information of China (English)

    陈五一; 陈鼎昌

    2000-01-01

    The basic structure of a virtual axis drill grinder is presented in terms of the spatial vectors and thegrinding parameters calculated according to the geometry of a helical drill point. The kinematic equations for sharpening the drills on the virtual axis grinder are deduced using the grinding parameters via vector-matrix txansformation.

  2. An off-axis digital holographic microscope with quasimonochromatic partially spatially coherent illumination in transmission

    Science.gov (United States)

    Grebenyuk, Anton A.; Tarakanchikova, Yana V.; Ryabukho, Vladimir P.

    2014-10-01

    We propose an off-axis imaging approach for digital holographic microscopy (DHM) with quasimonochromatic partially spatially coherent illumination in transmission, which is intended to provide the advantages of off-axis partially coherent DHM imaging with a comparatively simple optical scheme. This approach does not require a diffraction grating for creating the off-axis modality and also allows for convenient control of the spatial frequency of carrier interference fringes for hologram sampling optimization. Theoretical analysis of the off-axis imaging process in this microscope is performed. An off-axis DHM based on the proposed approach is built and quantitative phase imaging of test objects is performed with suppressed coherent noise.

  3. 2002–2012: 10 Years of Research Progress in Horizontal-Axis Marine Current Turbines

    Directory of Open Access Journals (Sweden)

    Kai-Wern Ng

    2013-03-01

    Full Text Available Research in marine current energy, including tidal and ocean currents, has undergone significant growth in the past decade. The horizontal-axis marine current turbine is one of the machines used to harness marine current energy, which appears to be the most technologically and economically viable one at this stage. A number of large-scale marine current turbines rated at more than 1 MW have been deployed around the World. Parallel to the development of industry, academic research on horizontal-axis marine current turbines has also shown positive growth. This paper reviews previous research on horizontal-axis marine current turbines and provides a concise overview for future researchers who might be interested in horizontal-axis marine current turbines. The review covers several main aspects, such as: energy assessment, turbine design, wakes, generators, novel modifications and environmental impact. Future trends for research on horizontal-axis marine current turbines are also discussed.

  4. Modal Parameter Identification of New Design of Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Chougule, Prasad; Nielsen, Søren R.K.

    2013-01-01

    Vertical axis wind turbines have lower power efficiency than the horizontal axis wind turbines. However vertical axis wind turbines are proven to be economical and noise free on smaller scale. A new design of three bladed vertical axis wind turbine by using two airfoils in construction of each...... blade has been proposed to improve power efficiency. The purpose of two airfoils in blade design of vertical axis wind turbine is to create high lift which in turns gives higher power output. In such case the structural parameter identification is important to understand the system behavior due to its...... Abaqus cae software. The study is limited to evaluate lowest fundamental modal frequencies and mode shapes of proposed wind turbine....

  5. Note: A compact three-axis optical force/torque sensor using photo-interrupters

    Science.gov (United States)

    Kim, Ji-Chul; Kim, Kyung-Soo; Kim, Soohyun

    2013-12-01

    By integrating four photo-interrupters in a cross-shaped structure, we developed a compact three-axis optical force/torque (F/T) sensor. The developed sensor has a diameter of 28 mm and a thickness of 7 mm. Despite simplicity and compactness, the experiments with a prototype of the proposed sensor demonstrate notably high accuracy. The RMS errors are 0.5% ± 0.1% of the maximum vertical force in z-axis, 1.9% ± 0.2% of the maximum torque in x-axis, and 2.0% ± 0.3% of the maximum torque in y-axis. It is expected that the proposed sensor allows cost-effective integration of robot systems requiring compact and multi-axis F/T sensors such as a walking assist robot.

  6. Minimizing cross-axis sensitivity in grating-based optomechanical accelerometers.

    Science.gov (United States)

    Lu, Qianbo; Wang, Chen; Bai, Jian; Wang, Kaiwei; Lou, Shuqi; Jiao, Xufen; Han, Dandan; Yang, Guoguang; Liu, Dong; Yang, Yongying

    2016-04-18

    Cross-axis sensitivity of single-axis optomechanical accelerometers, mainly caused by the asymmetric structural design, is an essential issue primarily for high performance applications, which has not been systematically researched. This paper investigates the generating mechanism and detrimental effects of the cross-axis sensitivity of a high resoluion single-axis optomechanical accelerometer, which is composed of a grating-based cavity and an acceleration sensing chip consisting of four crab-shaped cantilevers and a proof mass. The modified design has been proposed and a prototype setup has been built based on the model of cross-axis sensitivity in optomechanical accelerometers. The characterization of the cross-axis sensitivity of a specific optomechanical accelerometer is quantitatively discussed for both mechanical and optical components by numerical simulation and theoretical analysis in this work. The analysis indicates that the cross-axis sensitivity decreases the contrast ratio of the interference signal and the acceleration sensitivity, as well as giving rise to an additional optical path difference, which would impact the accuracy of the accelerometer. The improved mechanical design is achieved by double side etching on a specific double-substrate-layer silicon-on-insulator (SOI) wafer to move the center of the proof mass to the support plane. The experimental results demonstrate that the modified design with highly symmetrical structure can suppress the cross-axis sensitivity significantly without compromising the sensitivity and resolution. The cross-axis sensitivity defined by the contrast ratio of the output signal drops to 2.19% /0.1g from 28.28%/0.1g under the premise that the acceleration sensitivity of this single-axis optomechanical accelerometer remains 1162.45V/g and the resolution remains 1.325μg. PMID:27137337

  7. Comorbidity of axis I and axis II diagnoses in a sample of Egyptian patients with neurotic disorders.

    Science.gov (United States)

    Okasha, A; Omar, A M; Lotaief, F; Ghanem, M; Seif el Dawla, A; Okasha, T

    1996-01-01

    Neurosis and personality disorder (PD) are two of the most used but least clarified and understood terms in psychiatry. The separation of PD by the American Psychiatric Association in DSM-III and -IV as a discrete axis of classification has been a major advance in psychiatric nosology. Also with the advent of DSM-III and its multiaxial system, it was recognized that both PD and clinical syndromes can coexist, and in some cases this coexistence may have implications on treatment response and prognosis. This study was performed on 200 neurotic patients in an attempt to investigate possible correlations between various neurotic subcategories and personality types. Our results confirm that PD and personality abnormality are significantly higher in neurotic patients than in controls and need to be considered in diagnostic assessment. Some comorbidity was shown between borderline PD and somatoform disorder; compulsive PD and obsessive-compulsive disorder (OCD), and generalized anxiety disorder (GAD); and avoidant PD and phobia. However, our data failed to show a correlation between the presence of an additional PD and particular neurotic symptomatology. It seems that the association between neurotic disorders and PD should not be taken to indicate a direct causative relationship. It is likely that personality is just one of the predisposing factors that influence the individual response to psychological trauma and determine the form of neurosis. The most prevalent PD was found to be PD NOS, followed by borderline, compulsive, avoidant, and finally histrionic PDs. The term, multiple PD, should be given substance to characterize the diagnosis as a disorder, rather than leaving it at its current status of what seems to be a nondistinct clinical picture. Extensive research has to be undertaken in an attempt to decide which specific PDs most deserve to be included in the official nomenclature. PMID:8654069

  8. The Role of Anti-Phase Domains in InSb-Based Structures Grown on On-Axis and Off-Axis Ge Substrates

    Energy Technology Data Exchange (ETDEWEB)

    Debnath, M. C.; Mishima, T. D.; Santos, M. B. [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, Norman, OK 73019 (United States); Hossain, K.; Holland, O. W. [Amethyst Research, Inc., 1405 4th Ave NW, Ardmore, OK 73401 (United States)

    2011-12-26

    Anti-phase domains form in InSb epilayers and InSb/Al{sub 0.20}In{sub 0.80}Sb single quantum wells when grown upon on-axis (001) Ge substrates by molecular beam epitaxy. Domain formation is partially suppressed through growth on Ge substrates with surfaces that are several degrees off the (001) or (211) axis. By using off-axis Ge substrates, room-temperature electron mobilities increased to {approx}60,000 cm{sup 2}/V-s and {approx}14,000 cm{sup 2}/V-s for a 4.0-{mu}m-thick InSb epilayer and a 25-nm InSb quantum well, respectively.

  9. The Role of Anti-Phase Domains in InSb-Based Structures Grown on On-Axis and Off-Axis Ge Substrates

    International Nuclear Information System (INIS)

    Anti-phase domains form in InSb epilayers and InSb/Al0.20In0.80Sb single quantum wells when grown upon on-axis (001) Ge substrates by molecular beam epitaxy. Domain formation is partially suppressed through growth on Ge substrates with surfaces that are several degrees off the (001) or (211) axis. By using off-axis Ge substrates, room-temperature electron mobilities increased to ∼60,000 cm2/V-s and ∼14,000 cm2/V-s for a 4.0-μm-thick InSb epilayer and a 25-nm InSb quantum well, respectively.

  10. The relationship between personality disorders and Axis I psychopathology: deconstructing comorbidity.

    Science.gov (United States)

    Links, Paul S; Eynan, Rahel

    2013-01-01

    The purpose of this review is (a) to study and systematically review the recent literature examining the co-occurrence and relationships between Axis I psychiatric disorders and Axis II personality disorders, specifically the six originally proposed for the Diagnostic and Statistical Manual of Mental Disorders (DSM)-5, and (b) to consider the clinical utility of the current Axis I and Axis II approach in the DSM-IV-TR and apply findings to state a position on the issue of collapsing together Axis I and Axis II. Community surveys or prospective cohort studies were reviewed as a priority. Our review indicates that the associations between clinical disorders and personality disorders clearly varied within each disorder and across the six personality disorders. Our understanding has advanced, particularly related to the clinical utility of comorbidity, and there may be sufficient evidence to support moving borderline personality disorder to Axis I. However, it seems premature to conclude that comorbidity is best conceptualized by having all disorders in a single category or by deleting disorders so that comorbidity is reduced. Our review suggests some priorities for future research into comorbidity, such as including personality disorders in future multivariate comorbidity models. PMID:23157449

  11. Dynamic transitions in a model of the hypothalamic-pituitary-adrenal axis

    Science.gov (United States)

    Čupić, Željko; Marković, Vladimir M.; Maćešić, Stevan; Stanojević, Ana; Damjanović, Svetozar; Vukojević, Vladana; Kolar-Anić, Ljiljana

    2016-03-01

    Dynamic properties of a nonlinear five-dimensional stoichiometric model of the hypothalamic-pituitary-adrenal (HPA) axis were systematically investigated. Conditions under which qualitative transitions between dynamic states occur are determined by independently varying the rate constants of all reactions that constitute the model. Bifurcation types were further characterized using continuation algorithms and scale factor methods. Regions of bistability and transitions through supercritical Andronov-Hopf and saddle loop bifurcations were identified. Dynamic state analysis predicts that the HPA axis operates under basal (healthy) physiological conditions close to an Andronov-Hopf bifurcation. Dynamic properties of the stress-control axis have not been characterized experimentally, but modelling suggests that the proximity to a supercritical Andronov-Hopf bifurcation can give the HPA axis both, flexibility to respond to external stimuli and adjust to new conditions and stability, i.e., the capacity to return to the original dynamic state afterwards, which is essential for maintaining homeostasis. The analysis presented here reflects the properties of a low-dimensional model that succinctly describes neurochemical transformations underlying the HPA axis. However, the model accounts correctly for a number of experimentally observed properties of the stress-response axis. We therefore regard that the presented analysis is meaningful, showing how in silico investigations can be used to guide the experimentalists in understanding how the HPA axis activity changes under chronic disease and/or specific pharmacological manipulations.

  12. Design of off-axis mirrors for the phase-induced amplitude apodization complex mask coronagraph

    Science.gov (United States)

    Pluzhnik, Eugene; Guyon, Olivier; Belikov, Ruslan; Bendek, Eduardo

    2016-01-01

    The phase-induced amplitude apodization complex mask coronagraph (PIAACMC) provides an efficient way to control diffraction propagation effects caused by the central obstruction/segmented mirrors of the telescope. PIAACMC can be optimized in a way that takes into account both chromatic diffraction effects caused by the telescope obstructed aperture and the tip-tilt sensitivity of the coronagraph. As a result, unlike classic phase-induced amplitude apodization (PIAA), the PIAACMC mirror shapes are often slightly asymmetric even for an on-axis configuration and require more care in calculating off-axis shapes when an off-axis configuration is preferred. A method to design off-axis PIAA mirror shapes given an on-axis mirror design is presented. The algorithm is based on geometrical ray tracing and is able to calculate off-axis PIAA mirror shapes for an arbitrary geometry of the input and output beams. The method is demonstrated using the third generation PIAACMC design for WFIRST-AFTA telescope. Geometrical optics design issues related to the off-axis diffraction propagation effects are also discussed.

  13. Evanescent wave scattering at off-axis incidence on multiple cylinders located near a surface

    International Nuclear Information System (INIS)

    The scattering characteristics of an infinite cylinder are strongly influenced by the incidence angle relative to its axis. If the incident wave propagates in the plane normal to the axis of the cylinder, the polarization of the scattered wave remains unchanged and the scattered wave propagates in the same plan as the incident wave. At off-axis incidence such that the incident direction makes an oblique angle with the cylinder axis, the scattered wave is depolarized, and its spatial distribution becomes three-dimensional. This paper presents the scattering solution for oblique incidence on multiple parallel cylinders located near a planar interface by an evanescent wave that is generated by total internal reflection of the source wave propagating in the higher refractive index substrate. Hertz potentials are utilized to formulate the interaction of inhomogeneous waves with the cylinders, scattering at the substrate interface, and near field scattering between the cylinders. Analytic formulas are derived for the electromagnetic fields and Poynting vector of scattered radiation in the near-field and their asymptotic forms in the far-field. Numerical examples are shown to illustrate scattering of evanescent wave by multiple cylinders at off-axis incidence. - Highlights: • Developed an exact solution for off-axis incidence on multiple cylinders. • Included depolarization, near-field scattering, and Fresnel effect in theory. • Derived analytic formulas for scattered radiation in the far field. • Illustrated evanescent scattering at off-axis incidence by numerical data

  14. Analyses of surgically induced astigmatism and axis deviation in microcoaxial phacoemulsification.

    Science.gov (United States)

    Özyol, Erhan; Özyol, Pelin

    2014-06-01

    To evaluate surgically induced astigmatism (SIA) and axis deviation after coaxial microincision superotemporal clear corneal phacoemulsification incision in eyes with differently located steep axis. This prospective, comparative study included four groups of 45 eyes with age-related cataracts; each group underwent 2.2-mm superotemporal clear corneal incision (CCI) cataract surgery. The four groups of patients were divided by location of the steep axis. Groups were matched according to symmetry of the steep axis for both right and left eyes as follows--0°-45° of steep axis for right eyes, and 136°-180° for left eyes (group 1); 46°-90° for right eyes and 91°-135° for left eyes (group 2); 91°-135° for right eyes and 46°-90° for left eyes (group 3); and 136°-180° for right eyes and 0°-45° for left eyes (group 4). Outcome measures included changes in mean total astigmatism, SIA, and axis deviation. Astigmatism was measured by manual keratometry readings before surgery and week 1, week 4, week 8, and week 12 postoperatively. SIA was calculated by the vector analysis (Holladay-Cravy-Koch method). The magnitude of mean total astigmatism was lowest in group 3 and highest in group 1 at week 12. SIA was 0.39 diopters (D), 0.22 D, 0.17 D, and 0.28 D in group 1, group 2, group 3, and group 4, respectively. The change in astigmatic axis deviation was highest in group 3 (23.6 ± 16.6) (P < 0.05). Axis deviation and SIA were stable after week 4. Planning of CCI on or near the steep axis can help decrease corneal astigmatism. PMID:24081915

  15. Inclusion of the glucocorticoid receptor in a hypothalamic pituitary adrenal axis model reveals bistability

    Directory of Open Access Journals (Sweden)

    Vernon Suzanne D

    2007-02-01

    Full Text Available Abstract Background The body's primary stress management system is the hypothalamic pituitary adrenal (HPA axis. The HPA axis responds to physical and mental challenge to maintain homeostasis in part by controlling the body's cortisol level. Dysregulation of the HPA axis is implicated in numerous stress-related diseases. Results We developed a structured model of the HPA axis that includes the glucocorticoid receptor (GR. This model incorporates nonlinear kinetics of pituitary GR synthesis. The nonlinear effect arises from the fact that GR homodimerizes after cortisol activation and induces its own synthesis in the pituitary. This homodimerization makes possible two stable steady states (low and high and one unstable state of cortisol production resulting in bistability of the HPA axis. In this model, low GR concentration represents the normal steady state, and high GR concentration represents a dysregulated steady state. A short stress in the normal steady state produces a small perturbation in the GR concentration that quickly returns to normal levels. Long, repeated stress produces persistent and high GR concentration that does not return to baseline forcing the HPA axis to an alternate steady state. One consequence of increased steady state GR is reduced steady state cortisol, which has been observed in some stress related disorders such as Chronic Fatigue Syndrome (CFS. Conclusion Inclusion of pituitary GR expression resulted in a biologically plausible model of HPA axis bistability and hypocortisolism. High GR concentration enhanced cortisol negative feedback on the hypothalamus and forced the HPA axis into an alternative, low cortisol state. This model can be used to explore mechanisms underlying disorders of the HPA axis.

  16. Comparison of Efficiencies of Solar Tracker systems with static panel Single- Axis Tracking System and Dual-Axis Tracking System with Fixed Mount

    OpenAIRE

    Dhanabal.R; Bharathi.V; Ranjitha.R; Ponni.A; Deepthi.S; Mageshkannan.P

    2013-01-01

    Electricity plays a key role now in our daily lives but the energy sources to electric power has been used in abundance and so researchers were compelled to find an alternate source of power leading to the discovery of solar energy. Solar energy is inexhaustible and eco-friendly and can be converted into electricityusing photovoltaic panels. These panels can be used in a fixed form or used in a solar tracking system for single axis as well as for dual axis. In a fixed form their efficiency is...

  17. Description of multi-quasiparticle bands by the tilted axis cranking model 21.60.-n; High K rotational bands; Tilted axis cranking; Multi-quasiparticle configurations

    CERN Document Server

    Frauendorf, S

    2000-01-01

    The selfconsistent cranking approach is extended to the case of rotation about an axis which is tilted with respect to the principal axes of the deformed potential (Tilted Axis Cranking). Expressions for the energies and the intra bands electro-magnetic transition probabilities are given. The mean field solutions are interpreted in terms of quantal rotational states. The construction of the quasiparticle configurations and the elimination of spurious states is discussed. The application of the theory to high spin data is demonstrated by analyzing the multi-quasiparticle bands in the nuclides with N=102,103 and Z=71,72,73.

  18. Off-axis reflecting telescope with axially-symmetric optical property and its applications

    Science.gov (United States)

    Chang, Seunghyuk

    2006-06-01

    The basic concept and fundamental result of a recently developed geometric aberration theory for classical off-axis reflecting telescopes and imaging systems are presented. It is shown that a classical off-axis reflecting telescope can be designed to have practically axially-symmetric optical property by eliminating the dominant aberration (linear astigmatism) caused by the asymmetric geometry. A simple closed-form equation for elimination of linear astigmatism is presented. Also, to show how the developed aberration theory can be applied to current and future telescopes, several off-axis reflecting telescopes and imaging systems are designed and analyzed.

  19. Numerical simulation in vertical wind axis turbine with pitch controlled blades

    OpenAIRE

    BAYEUL-LAINE, Annie-Claude; DOCKTER, Aurore; Bois, Gérard; Simonet, Sophie

    2012-01-01

    Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be model...

  20. NUMERICAL SIMULATION IN VERTICAL WIND AXIS TURBINE WITH PITCH CONTROLLED BLADES

    OpenAIRE

    BAYEUL-LAINE, Annie-Claude; DOCKTER, Aurore; Bois, Gérard; Simonet, Sophie

    2011-01-01

    Wind energy is more and more used as a renewable energy source character. The present wind turbine is a small one which allows to be used on roofs or in gardens to light small areas like publicity boards, parking, roads or for water pumping, heating... The present turbine has a vertical axis. Each turbine blade combines a rotating movement around its own axis and around the main rotor axis. Due to this combination of movements, flow around this turbine is highly unsteady and needs to be model...

  1. Tunable three-axis magnetoresistance sensor with a spin-polarised current

    Science.gov (United States)

    Chang, Jui-Hang; Chang, Ching-Ray

    2015-10-01

    A three-axis magnetic tunnel junction sensor with three ferromagnetic layers to achieve a linear and hysteresis-free response is proposed and studied analytically. We show that the orientation of the easy axis of the sensor and the sensitivity are tunable by changing the density of a injected spin-polarised current. Additionally, the sensors integrated in a full Wheatstone bridge can have perpendicular and transverse sensing capability in different initial magnetisation arrangements. A value of 0.35% TMR/Oe is observed in sensing the perpendicular field. These findings indicate that a three-axis sensor can be fabricated more easily on a flat substrate.

  2. Verification of optical coordinate measuring machines along the vertical measurement axis

    DEFF Research Database (Denmark)

    Morace, Renata Erica; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    This paper deals with the performance verification of optical coordinate measuring machines (CMMs) equipped with video probes along the vertical measurement axis. The aim of this work was to investigate the capability of artefacts like gauge blocks and angle blocks for calibrating, verifying and...... monitoring optical CMMs along the Z axis. The performance of an optical CMM was checked by the use of a laser interferometer, gauge blocks and angle blocks. Positioning errors and measurement errors along the Z axis and angular errors in the XZ plane were evaluated. Results have shown that the use of gauge...

  3. Effects of Temperature on Weak Principal Axis of Twisted Fiber Loop

    Institute of Scientific and Technical Information of China (English)

    XU Ling; YAO Shou-quan

    2004-01-01

    Theoretically and experimentally, the effects of temperature on the weak principal axis of twisted optical fiber loop are analyzed, and the results show that the location of the pair of weak principal axis will drift with temperature change, which will deteriorate the stability of system when applied to sensor system. In this paper, the influence of phase drift of weak principal axis on the performance of optical fiber current sensor is mainly predicted theoretically. Our research results will provide a beneficial reference for improving optical fiber sensor system.

  4. Evaluation of a Blade Force Measurement System for a Vertical Axis Wind Turbine Using Load Cells

    OpenAIRE

    Morgan Rossander; Eduard Dyachuk; Senad Apelfröjd; Kristian Trolin; Anders Goude; Hans Bernhoff; Sandra Eriksson

    2015-01-01

    Unique blade force measurements on an open site straight-bladed vertical axis wind turbine have been performed. This paper presents a method for measuring the tangential and normal forces on a 12-kW vertical axis wind turbine prototype with a three-bladed H-rotor. Four single-axis load cells were installed in-between the hub and the support arms on one of the blades. The experimental setup, the measurement principle, together with the necessary control and measurement system are described. Th...

  5. Design and realization of test system for testing parallelism and jumpiness of optical axis of photoelectric equipment

    Science.gov (United States)

    Shi, Sheng-bing; Chen, Zhen-xing; Qin, Shao-gang; Song, Chun-yan; Jiang, Yun-hong

    2014-09-01

    With the development of science and technology, photoelectric equipment comprises visible system, infrared system, laser system and so on, integration, information and complication are higher than past. Parallelism and jumpiness of optical axis are important performance of photoelectric equipment,directly affect aim, ranging, orientation and so on. Jumpiness of optical axis directly affect hit precision of accurate point damage weapon, but we lack the facility which is used for testing this performance. In this paper, test system which is used fo testing parallelism and jumpiness of optical axis is devised, accurate aim isn't necessary and data processing are digital in the course of testing parallelism, it can finish directly testing parallelism of multi-axes, aim axis and laser emission axis, parallelism of laser emission axis and laser receiving axis and first acuualizes jumpiness of optical axis of optical sighting device, it's a universal test system.

  6. Measurement of off-axis and peripheral skin dose using radiochromic film

    International Nuclear Information System (INIS)

    A radiotherapy skin dose profile can be obtained with radiochromic film. The central axis skin dose relative to Dmax for a 10x10cm2 field size was found to be 22%, 17% and 15.5% for 6 MV, 10 MV and 18 MV photon beams. Peripheral dose increased with increasing field size. At 10 MV the skin dose 2 cm outside the geometric field edge was measured as 6%, 10% and 17% for 10x10cm2, 20x20cm2 and 30x30cm2 field sizes respectively. Off-axis skin dose decreased as distance increased from central axis for fields with Perspex block trays. For a 20x20cm2 field, an approximately 5-8% drop in percentage skin dose was observed from central axis to the beam edge. (author)

  7. Indications of c-axis Charge Transport in Hole Doped Triangular Antiferromagnets

    Institute of Scientific and Technical Information of China (English)

    LIANG Ying; LIU Bin; FENG Shi-Ping

    2004-01-01

    The c-axis charge transport of the hole doped triangular antiferromagnet is investigated within the tJ model by considering the incoherent interlayer hopping.It is shown that the c-axis charge transport of the hole doped triangular antiferromagnet is essentially determined by the scattering from the in-plane fluctuation.The c-axis conductivity spectrum shows a lov-energy peak and the unusual high-energy broad band,while the c-axis resistivity is characterized by a crossover from the high temperature metallic-like behavior to the Iow temperature insulating-like behavior,which is qualitatively consistent with those of the hole doped square lattice antiferromagnet.

  8. Distribution of three microvillar enzymes along the small intestinal crypt-villus axis

    DEFF Research Database (Denmark)

    Hansen, Gert Helge; Niels-Christiansen, L L; Poulsen, M D;

    1994-01-01

    of the axis, whereas ApN is found mainly in the villar and upper crypt enterocytes. All three enzymes are detected in the basolateral membrane at all levels along the crypt-villus axis, although ApN and S-I only occurred at low intensities in the villus region. The microvillar/basolateral labelling...... ratio for the three enzymes increases to a varying degree for the three enzymes along the axis suggesting that the sorting efficiency to the apical membrane improves at least for ApN and S-I as the cells mature. These findings might indicate that the enterocytes change from a transcytotic to a direct......Aminopeptidase N (ApN), dipeptidyl peptidase IV (DPP IV) and sucrose-isomaltase (S-I) are differentially expressed along the pig jejunum crypt-villus axis. Quantitative immunoelectron microscopy and enzyme cytochemistry show that DPP IV and S-I are expressed in enterocytes along the entire length...

  9. Characterization of reactively sputtered c-axis aligned nanocrystalline InGaZnO4

    International Nuclear Information System (INIS)

    Crystallinity and texturing of RF sputtered c-axis aligned crystal InGaZnO4 (CAAC IGZO) thin films were quantified using X-ray diffraction techniques. Above 190 °C, nanocrystalline films with an X-ray peak at 2θ = 30° (009 planes) developed with increasing c-axis normal texturing up to 310 °C. Under optimal conditions (310 °C, 10% O2), films exhibited a c-axis texture full-width half-maximum of 20°. Cross-sectional high-resolution transmission electron microscopy confirmed these results, showing alignment variation of ±9° over a 15 × 15 nm field of view and indicating formation of much larger aligned domains than previously reported. At higher deposition temperatures, c-axis alignment was gradually lost as polycrystalline films developed

  10. Characterization of reactively sputtered c-axis aligned nanocrystalline InGaZnO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, David M.; Zhu, Bin; Ast, Dieter G.; Thompson, Michael O. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Levin, Barnaby D. A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Muller, David A. [School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute for Nanoscale Science, Cornell University, Ithaca, New York 14853 (United States); Greene, Raymond G. [Corning Incorporated, Corning, New York 14831 (United States)

    2014-12-29

    Crystallinity and texturing of RF sputtered c-axis aligned crystal InGaZnO{sub 4} (CAAC IGZO) thin films were quantified using X-ray diffraction techniques. Above 190 °C, nanocrystalline films with an X-ray peak at 2θ = 30° (009 planes) developed with increasing c-axis normal texturing up to 310 °C. Under optimal conditions (310 °C, 10% O{sub 2}), films exhibited a c-axis texture full-width half-maximum of 20°. Cross-sectional high-resolution transmission electron microscopy confirmed these results, showing alignment variation of ±9° over a 15 × 15 nm field of view and indicating formation of much larger aligned domains than previously reported. At higher deposition temperatures, c-axis alignment was gradually lost as polycrystalline films developed.

  11. The development and testing of a novel cross axis wind turbine

    Science.gov (United States)

    Chong, W. T.; Muzammil, W. K.; Gwani, M.; Wong, K. H.; Fazlizan, A.; Wang, C. T.; Poh, S. C.

    2016-06-01

    A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

  12. Update on stress and depression: the role of the hypothalamic-pituitary-adrenal (HPA axis

    Directory of Open Access Journals (Sweden)

    Mello Andrea de Abreu Feijó de

    2003-01-01

    Full Text Available Over the past 50 years, relationships between stress and the neurobiological changes seen in psychiatric disorders have been well-documented. A major focus of investigations in this area has been the role of the hypothalamic-pituitary-adrenal (HPA axis, both as a marker of stress response and as a mediator of additional downstream pathophysiologic changes. This review examines the emerging literature concerning the relationship between stress, HPA axis function, and depression, as well as the role of early life stress as an important risk factor for HPA axis dysregulation. The more recent studies reviewed suggest that the prominence of HPA axis hyperactivity in adults with depressive and anxiety disorders may constitute a link between the occurrence of adversity in childhood and the development of adult psychopathology

  13. Six-Axis Force-Torque Transducer for Mars 2018 Mission Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A transducer element that is hearty enough for a Mars lander mission needs to be developed so that a six-axis force and torque transducer is possible. The technical...

  14. Normalized Point Source Sensitivity for Off-Axis Optical Performance Evaluation of the Thirty Meter Telescope

    Science.gov (United States)

    Seo, Byoung-Joon; Nissly, Carl; Troy, Mitchell; Angeli, George

    2010-01-01

    The Normalized Point Source Sensitivity (PSSN) has previously been defined and analyzed as an On-Axis seeing-limited telescope performance metric. In this paper, we expand the scope of the PSSN definition to include Off-Axis field of view (FoV) points and apply this generalized metric for performance evaluation of the Thirty Meter Telescope (TMT). We first propose various possible choices for the PSSN definition and select one as our baseline. We show that our baseline metric has useful properties including the multiplicative feature even when considering Off-Axis FoV points, which has proven to be useful for optimizing the telescope error budget. Various TMT optical errors are considered for the performance evaluation including segment alignment and phasing, segment surface figures, temperature, and gravity, whose On-Axis PSSN values have previously been published by our group.

  15. Lagrangian neoclassical transport theory applied to the region near the magnetic axis

    International Nuclear Information System (INIS)

    Neoclassical transport theory around the magnetic axis of a tokamak is studied, in which relatively wide ''potato'' orbits play an important role in transport. Lagrangian formulation of transport theory, which has been investigated to reflect finiteness of guiding-center orbit widths to transport equations, is developed in order to analyze neoclassical transport near the axis for a low-collisionality plasma. The treatment of self-collision term in Lagrangian formulation is revised to retain momentum conservation property of it. With directly reflecting the orbital properties of all the types of orbits in calculation, the ion thermal conductivity around the axis is found to decrease than from that predicted by conventional neoclassical theory. This result supports recent numerical simulations which show the reduction of thermal conductivity near the magnetic axis. (author)

  16. Electron Traps in GaAs Grown by Molecular Beam Epitaxy on On-axis (100 and Off-axis Substrates

    Directory of Open Access Journals (Sweden)

    R. Sarmiento

    2003-06-01

    Full Text Available Deep level transient spectroscopy (DLTS was used to characterize the electron traps present in the bulkGaAs grown by molecular beam epitaxy (MBE on on-axis (100 and off-axis (4° towards the (111 Adirection substrates. Two electron traps were obtained for each sample having identical correspondingpeak locations in the DLTS spectra. The layer grown on the on-axis substrate has electron traps withactivation energies of EC–0.454 eV and EC–0.643 eV and capture cross-sections of 1.205 x 10-14 cm2 and3.88 x 10-15 cm2, respectively. The layer grown on the off-axis substrate has traps with activation energiesof EC–0.454 eV and EC–0.723 eV and capture cross-sections of 2.060 x 10-14 cm2 and 4.40 x 10-14 cm2.The electron traps are possibly the M4 (or EL3 and EL2 (or EB4 traps commonly found in GaAs layers.Due to the high trap concentrations obtained and to the non-uniform trap concentration profile, Asdesorption may be considerable during growth.

  17. The effects of eccentricities on the fracture of off-axis fiber composites

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    Finite element analyses were performed to investigate theoretically the effects of in-plane and out-of plane eccentricities, bending or twisting, and thickness nonuniformity on the axial stress and strain variations across the width of off-axis specimens. The results are compared with measured data and are also used to access the effects of these eccentricities on the fracture stress of off-axis fiber composites. Guidelines for detecting and minimizing the presence of eccentricities are described.

  18. Impact of Sleep and Its Disturbances on Hypothalamo-Pituitary-Adrenal Axis Activity

    OpenAIRE

    Marcella Balbo; Rachel Leproult; Eve Van Cauter

    2010-01-01

    The daily rhythm of cortisol secretion is relatively stable and primarily under the influence of the circadian clock. Nevertheless, several other factors affect hypothalamo-pituitary-adrenal (HPA) axis activity. Sleep has modest but clearly detectable modulatory effects on HPA axis activity. Sleep onset exerts an inhibitory effect on cortisol secretion while awakenings and sleep offset are accompanied by cortisol stimulation. During waking, an association between cortisol secretory bursts and...

  19. STRONG DAMPING OF THE C-AXIS PLASMON IN HIGH-T-C CUPRATE SUPERCONDUCTORS

    NARCIS (Netherlands)

    Kim, J.H; Somal, H.S; Czyzyk, M.T; der Marel, D.van; Wittlin, A.; Gerrits, A.M.; Duijn, V.H.M.; Hien, N.T.; Menovsky, A.A.

    1995-01-01

    We analyze the infrared reflectivity of La1.85Sr0.15CuO4 single crystals with E parallel to the c-axis. The plasma edge at around 6 meV (50 cm(-1)), which occurs only for T axis plasma frequ

  20. Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

    OpenAIRE

    Yan Ren; Zhenghua Liu; Le Chang; Nuan Wen

    2013-01-01

    A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mod...

  1. Design and dynamic analysis of single-axis integrated inertia measurement device

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The structure and measurement theory of a single-axis integrated inertia measurement device are discussed in this paper.The acceleration and angle velocity can be detected by the proposed sensor at the same time.The kinetic model of the device is also established.In addition,the signal generation of the single-axis integrated inertiameasurement device is analyzed and simulated.The results of the model are consistent with simulation result.

  2. Suppression of Adult Neurogenesis Leads to an Increased HPA Axis Response

    OpenAIRE

    Schloesser, Robert J.; Manji, Husseini K.; Martinowich, Keri

    2009-01-01

    Stress and glucocorticoids are among the strongest inhibitors of adult hippocampal neurogenesis. Despite the known role of the hippocampus in negative feedback regulation of the hypothalamo-pituitary adrenal axis, whether loss of hippocampal neurogenesis affects this inhibition has not been examined. Here we tested whether suppression of adult neurogenesis affected the hypothalamo-pituitary-adrenal axis response. Our results show that suppression of neurogenesis leads to a potentiated hypotha...

  3. Genetic variation and HPA axis activity: implications for diagnosis and treatment

    OpenAIRE

    Alan Schatzberg; Ned H. Kalin; Pandey, Ghanshyam N; Belanoff, Joseph K.

    2012-01-01

    Background : Hypothalamic–pituitary–adrenal (HPA) axis activity remains a major focus for the study of the pathophysiology of anxiety and depressive disorders. Recent developments in genetics allow for potential new avenues for assessing risk and for developing new treatments. We will address recent studies on genetics of HPA axis dysregulation in a preclinical model of anxiety/depression, the brains of suicide victims, and severely ill delusional and nondelusional depressives. ...

  4. Hypothalamic-pituitary-adrenal axis modulation of GABAergic neuroactive steroids influences ethanol sensitivity and drinking behavior

    OpenAIRE

    Morrow, A. Leslie; Porcu, Patrizia; Boyd, Kevin N.; Grant, Kathleen A.

    2006-01-01

    Activation of the hypothalamic-pituitary-adrenal (HPA) axis leads to élévations in γ-aminobutyric acid (GABA)-ergic neuroactive steroids that enhance GABA neurotransmission and restore homeostasis following stress. This régulation of the HPA axis maintains healthy brain function and protects against neuropsychiatrie disease. Ethanol sensitivity is influenced by élévations in neuroactive steroids that enhance the GABAergic effects of ethanol, and mayprevent excessive drinking in rodents and hu...

  5. Calculation of d- and q-axis inductances of PM brushless ac machines accounting for Skew

    OpenAIRE

    Chen, Y. S.; Zhu, Z.Q.; Howe, D.

    2005-01-01

    A hybrid two-dimensional (2-D) finite-element/analytical technique is described for predicting the d-axis and q-axis inductances of permanent magnet (PM) brushless ac machines, with due account for the influence of skew. Predicted inductances are compared with measured values for two machines having identical stators, which are skewed by one slot-pitch, but which have different rotor topologies, one having surface-mounted magnets and the other having interior magnets.

  6. The hypothalamic-pituitary-adrenal-axis in the regulation of energy balance.

    Science.gov (United States)

    Nieuwenhuizen, Arie G; Rutters, Femke

    2008-05-23

    Human (visceral) obesity is associated with alterations hypothalamus-pituitary-adrenal (HPA) axis functioning. It is however not completely clear whether the HPA axis is causally or co-incidentally related to (visceral) obesity. This review summarizes supporting data of an involvement of the HPA axis in the development of (visceral) obesity. First, several DNA polymorphisms related to HPA axis functioning are correlated to the development of obesity. Second, chronic elevation of circulatory glucocorticoid concentrations, as in Cushing's disease, results in increased abdominal adiposity. Third, (visceral) obesity is associated with a diminished capacity of cortisol to suppress its own secretion. HPA axis functioning might affect energy balance through affecting energy intake. Both CRH and cortisol influence physiological, central mechanisms involved in the regulation of food intake. Still, general activation of the HPA axis has shown to have inconsistent effects on food intake in humans. This inconsistency may partially be explained by gender differences, individual differences in the functioning of the HPA axis, as well as differences in attitude towards eating. In particular, women with high scores on dietary restraint are prone to stress-induced hyperphagia. Dietary restraint scores, in turn, are positively correlated to basal and dexamethasone-suppressed cortisol levels, indicating a complex dual relationship between stress, HPA axis functioning, attitude towards eating and the risk for stress-induced hyperphagia. In the Western society, with chronically high ambient levels of stress and the availability of high caloric foods, this relationship may imply a risk for the development of (visceral) obesity and the metabolic syndrome. PMID:18275977

  7. Process simulation for 5-axis machining using generalized milling tool geometries

    OpenAIRE

    Özkırımlı, Ömer Mehmet; Ozkirimli, Omer Mehmet; Budak, Erhan

    2010-01-01

    Multi-axis machining (especially 5-axis machining) is widely used in precision machining for automotive, aerospace and die-mold manufacturing. The goal in precision machining is to increase production while meeting high part quality needs which can be achieved through decision of appropriate process parameters considering machine tool constraints (such as power and torque), chatter-free operations and part quality. In order to predict and decide on optimal process parameters, simulation model...

  8. Experimental Study of Aerodynamic Characteristics for Horizontal Axis Wind Turbine and Performance Evaluation

    OpenAIRE

    Dai Yuanjun; Wen Caifeng

    2012-01-01

    This study using two different airfoil of horizontal axis wind turbine in order to evaluate the performance good or bad with unit area of power generation. First, under the low speed wind tunnel, two different airfoil of horizontal axis wind turbine on experimental study of the aerodynamic characteristics, got the power curve of wind turbine; Then, based on the wind resource date in 2008 from four areas in Inner Mongolia, which was provided by the China meteorological date sharing service sys...

  9. THREE-AXIS AIR-BEARING BASED PLATFORM FOR SMALL SATELLITE ATTITUDE DETERMINATION AND CONTROL SIMULATION.

    OpenAIRE

    Contreras, F.; de Vicente, E; Reyes, L.; G. Bisiacchi; Prado, J; M. Mesinas; Juárez, A

    2005-01-01

    A frictionless environment simulation platform, utilized for accomplishing three-axis attitude control tests in small satellites,is introduced. It is employed to develop, improve, and carry out objective tests of sensors, actuators, and algorithms in theexperimental framework. Different sensors (i.e. sun, earth, magnetometer, and an inertial measurement unit) are utilizedto assess three-axis deviations. A set of three inertial wheels is used as primary actuators for attitude control, together...

  10. Performance Analysis and Optimization of Sizable 6-Axis Force Sensor Based on Stewart Platform

    OpenAIRE

    Zhao, Y. Z.; Zhao, T. S.; Liu, L. H.; H. Bian; Li, N

    2008-01-01

    The paper plots the indices atlases based on the screw theory and definition of the performances indices, and summaries the law how structure parameters affect the indices. With the constructed optimization objective functions, the sizable parallel 6-axis force sensor's structure parameters are optimized in nonlinear single objective and multi-objective respectively. The corresponding optimal structure parameters are obtained. A novel sizable 6-axis force sensor with flexible joints is develo...

  11. Differential impact of chronic stress along the hippocampal dorsal–ventral axis

    OpenAIRE

    Pinto, Vítor; Costa, João Carlos Cardoso; Morgado, Pedro; Mota, Cristina de Fátima Sousa da; Miranda, A.; Bravo, Ana Francisca Rodrigues Vaz; Oliveira, Tiago Gil; Cerqueira, João; Sousa, Nuno

    2015-01-01

    Stress impacts differently in distinct brain regions. However, so far few studies have focused on the differential responses triggered by stressful stimuli on the intrinsic functional heterogeneity of the hippocampal axis. In this study, we assessed the functional and structural alterations caused by exposure to a chronic unpredictable stress (CUS) paradigm on the dorsal-ventral axis of the hippocampus. The morphological analysis demonstrated that CUS had opposite outcomes in the structure of...

  12. Chronic stress suppresses the expression of cutaneous hypothalamic-pituitary-adrenocortical axis elements and melanogenesis.

    Directory of Open Access Journals (Sweden)

    Silin Pang

    Full Text Available Chronic stress can affect skin function, and some skin diseases might be triggered or aggravated by stress. Stress can activate the central hypothalamic-pituitary-adrenocortical (HPA axis, which causes glucocorticoid levels to increase. The skin has HPA axis elements that react to environmental stressors to regulate skin functions, such as melanogenesis. This study explores the mechanism whereby chronic stress affects skin pigmentation, focusing on the HPA axis, and investigates the role of glucocorticoids in this pathway. We exposed C57BL/6 male mice to two types of chronic stress, chronic restraint stress (CRS and chronic unpredictable mild stress (CUMS. Mice subjected to either stress condition showed reduced melanogenesis. Interestingly, CRS and CUMS triggered reductions in the mRNA expression levels of key factors involved in the HPA axis in the skin. In mice administered corticosterone, decreased melanin synthesis and reduced expression of HPA axis elements were observed. The reduced expression of HPA axis elements and melanogenesis in the skin of stressed mice were reversed by RU486 (a glucocorticoid receptor antagonist treatment. Glucocorticoids had no significant inhibitory effect on melanogenesis in vitro. These results suggest that, high levels of serum corticosterone induced by chronic stress can reduce the expression of elements of the skin HPA axis by glucocorticoid-dependent negative feedback. These activities can eventually result in decreased skin pigmentation. Our findings raise the possibility that chronic stress could be a risk factor for depigmentation by disrupting the cutaneous HPA axis and should prompt dermatologists to exercise more caution when using glucocorticoids for treatment.

  13. Secondary embryonic axis formation by transplantation of D quadrant micromeres in an oligochaete annelid.

    Science.gov (United States)

    Nakamoto, Ayaki; Nagy, Lisa M; Shimizu, Takashi

    2011-01-01

    Among spiral cleaving embryos (e.g. mollusks and annelids), it has long been known that one blastomere at the four-cell stage, the D cell, and its direct descendants play an important role in axial pattern formation. Various studies have suggested that the D quadrant acts as the organizer of the embryonic axes in annelids, although this has never been demonstrated directly. Here we show that D quadrant micromeres (2d and 4d) of the oligochaete annelid Tubifex tubifex are essential for embryonic axis formation. When 2d and 4d were ablated the embryo developed into a rounded cell mass covered with an epithelial cell sheet. To examine whether 2d and 4d are sufficient for axis formation they were transplanted to an ectopic position in an otherwise intact embryo. The reconstituted embryo formed a secondary embryonic axis with a duplicated head and/or tail. Cell lineage analyses showed that neuroectoderm and mesoderm along the secondary axis were derived from the transplanted D quadrant micromeres and not from the host embryo. However, endodermal tissue along the secondary axis originated from the host embryo. Interestingly, when either 2d or 4d was transplanted separately to host embryos, the reconstituted embryos failed to form a secondary axis, suggesting that both 2d and 4d are required for secondary axis formation. Thus, the Tubifex D quadrant micromeres have the ability to organize axis formation, but they lack the ability to induce neuroectodermal tissues, a characteristic common to chordate primary embryonic organizers. PMID:21148182

  14. Traveling theta waves along the entire septo-temporal axis of the hippocampus

    OpenAIRE

    Patel, Jagdish; Fujisawa, Shigeyoshi; Berényi, Antal; Royer, Sébastien; Buzsáki, György

    2012-01-01

    A topographical relationship exists between the hippocampus-entorhinal cortex and the neocortex. However, it is not known how these anatomical connections are utilized during information exchange and behavior. We recorded theta oscillations along the entire extent of the septo-temporal axis of the hippocampal CA1 pyramidal layer. While the frequency of theta oscillation remained same along the entire long axis, the amplitude and coherence between recording sites decreased from dorsal to ventr...

  15. Non-axis-symmetrical punching shear around internal columns of RC slabs without transverse reinforcement

    OpenAIRE

    Sagaseta, Juan; Muttoni, Aurelio; Fernández Ruiz, Miguel; TASSINARI, Luca

    2011-01-01

    Most analytical approaches and available test data for punching shear in flat slabs assume axis-symmetrical conditions, which seems realistic for representing slabs supported on columns equally spaced in both orthogonal directions. However, in practice, there are many instances where loading, geometry and reinforcement around internal columns differ significantly from ideal axis-symmetrical conditions. Typical examples include slab bridges, flat slabs with unequal spans and footings with uneq...

  16. Bouncing back - trauma and the HPA-axis in healthy adults

    OpenAIRE

    Ellen Renée Klaassens

    2010-01-01

    Background Dysregulation of the hypothalamic–pituitary–adrenal (HPA)-axis is thought to underlie stress-related psychiatric disorders such as posttraumatic stress disorder (PTSD). Some studies have reported HPA-axis dysregulation in trauma-exposed (TE) adults in the absence of psychiatric morbidity. In this dissertation we set out to unravel part of the mechanism that underlies the complex relations between trauma exposure, stress regulation, and psychopathology. Method Mentally healthy TE su...

  17. 如何用Axis2开发Web Service服务

    Institute of Scientific and Technical Information of China (English)

    唐青

    2007-01-01

    Web Service是一种新的web应用程序分支.Apache Axis是较受欢迎的web service开发平台之一.主要介绍如果利用Axis2.1.0开发Web服务以及如何利用Axis2所提供的客户端API进行Web服务的调用.

  18. Stress and serial adult metamorphosis: multiple roles for the stress axis in socially regulated sex change

    OpenAIRE

    Solomon-Lane, Tessa K.; Crespi, Erica J.; Matthew Scott Grober

    2013-01-01

    Socially regulated sex change in teleost fishes is a striking example of social status information regulating biological function in the service of reproductive success. The establishment of social dominance in sex changing species is translated into a cascade of changes in behavior, physiology, neuroendocrine function, and morphology that transforms a female into a male, or vice versa. The hypothalamic-pituitary-interrenal axis (HPI, homologous to HP-adrenal axis in mammals and birds) has ...

  19. Fish schooling as a basis for vertical axis wind turbine farm design

    OpenAIRE

    Whittlesey, Robert W.; Liska, Sebastian; Dabiri, John O.

    2010-01-01

    Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases...

  20. Vertical axis wind turbine performance prediction: a new approach to the double multiple streamtube model

    OpenAIRE

    Melício, Rui; Batista, N.C.; Matias, J. C. O.; Catalão, J.P.S.

    2012-01-01

    The vertical axis wind turbines (VAWT) have been suffering an increased acceptance for urban wind turbines integration in the future smart grid for decentralized generation (DG). The VAWT have several advantages over the more conventional horizontal axis wind turbines (HAWT): the smaller number of components; low sound emissions; their insensitivity to fast changes in wind flow direction; a lower architectural visual impact; the ability to operate closer to the ground;...

  1. Three-Dimensional Velocity Measurements Around and Downstream of a Rotating Vertical Axis Wind Turbine

    OpenAIRE

    Ryan, Kevin J.; Coletti, Filippo; Dabiri, John O.; Eaton, John K.

    2014-01-01

    Modern designs for straight-bladed vertical axis wind turbines (VAWTs) feature smaller individual footprints than conventional horizontal axis wind turbines (HAWTs), allowing closer spacing of turbines and potentially greater power extraction for the same wind farm footprint. However, the wakes of upstream turbines could persist far enough to affect the performance of closely-spaced downstream turbines. In order to optimize the inter-turbine spacing and to investigate the potential for constr...

  2. Propagation evolution of an off-axis high-order cylindrical vector beam.

    Science.gov (United States)

    Li, Yang; Zhu, Zhuqing; Wang, Xiaolei; Gong, Liping; Wang, Ming; Nie, Shouping

    2014-11-01

    The propagation characteristics of an off-axis high-order cylindrical vector beam (OHCVB) are studied in this paper. The analytic expressions for the electric field and intensity distribution of the OHCVB propagating in free space are presented, to our knowledge for the first time. The transverse intensity of the OHCVB, different from that of the input Gaussian beam, does not have an axially symmetric distribution, owing to a slight dislocation between the polarization singularity located in the vector field generator and the center point of the Gaussian beam. Numerical results show that the intensity distribution during propagation strongly depends on the propagation distance, dislocation displacement, and topological charge. Accompanied by beam expansion, the intensity distribution of the OHCVB tends to eventually become steady, and the dark core of the vector beam will disappear gradually during the process of propagation. Moreover, with the increase of the topological charge, more energy will be transferred from the x axis to the y axis, and the annular intensity is split into two parts along the y-axis direction. The results help us to investigate the dynamic propagation behaviors of the HCVB under the off-axis condition and also guide the calibration of the off-axis high-order cylindrical vector field in practice. PMID:25401345

  3. Compensation method for the alignment angle error of a gear axis in profile deviation measurement

    International Nuclear Information System (INIS)

    In the precision measurement of involute helical gears, the alignment angle error of a gear axis, which was caused by the assembly error of a gear measuring machine, will affect the measurement accuracy of profile deviation. A model of the involute helical gear is established under the condition that the alignment angle error of the gear axis exists. Based on the measurement theory of profile deviation, without changing the initial measurement method and data process of the gear measuring machine, a compensation method is proposed for the alignment angle error of the gear axis that is included in profile deviation measurement results. Using this method, the alignment angle error of the gear axis can be compensated for precisely. Some experiments that compare the residual alignment angle error of a gear axis after compensation for the initial alignment angle error were performed to verify the accuracy and feasibility of this method. Experimental results show that the residual alignment angle error of a gear axis included in the profile deviation measurement results is decreased by more than 85% after compensation, and this compensation method significantly improves the measurement accuracy of the profile deviation of involute helical gear. (paper)

  4. The A/P axis in echinoderm ontogeny and evolution: evidence from fossils and molecules

    Science.gov (United States)

    Peterson, K. J.; Arenas-Mena, C.; Davidson, E. H.

    2000-01-01

    Even though echinoderms are members of the Bilateria, the location of their anterior/posterior axis has remained enigmatic. Here we propose a novel solution to the problem employing three lines of evidence: the expression of a posterior class Hox gene in the coeloms of the nascent adult body plan within the larva; the anatomy of certain early fossil echinoderms; and finally the relation between endoskeletal plate morphology and the associated coelomic tissues. All three lines of evidence converge on the same answer, namely that the location of the adult mouth is anterior, and the anterior/posterior axis runs from the mouth through the adult coelomic compartments. This axis then orients the animal such that there is but a single plane of symmetry dividing the animal into left and right halves. We tentatively hypothesize that this plane of symmetry is positioned along the dorsal/ventral axis. These axis identifications lead to the conclusion that the five ambulacra are not primary body axes, but instead are outgrowths from the central anterior/posterior axis. These identifications also shed insight into several other evolutionary mysteries of various echinoderm clades such as the independent evolution of bilateral symmetry in irregular echinoids, but do not elucidate the underlying mechanisms of the adult coelomic architecture.

  5. Proto-Model of an Infrared Wide-Field Off-Axis Telescope

    CERN Document Server

    Kim, Sanghyuk; Chang, Seunghyuk; Kim, Geon Hee; Yang, Sun Choel; Kim, Myung Sang; Lee, Sungho; Lee, Hanshin; 10.5303/JKAS.2010.43.5.169

    2010-01-01

    We develop a proto-model of an off-axis reflective telescope for infrared wide-field observations based on the design of Schwarzschild-Chang type telescope. With only two mirrors, this design achieves an entrance pupil diameter of 50 mm and an effective focal length of 100 mm. We can apply this design to a mid-infrared telescope with a field of view of 8 deg X 8 deg. In spite of the substantial advantages of off-axis telescopes in the infrared compared to refractive or on-axis reflective telescopes, it is known to be difficult to align the mirrors in off-axis systems because of their asymmetric structures. Off-axis mirrors of our telescope are manufactured at the Korea Basic Science Institute (KBSI). We analyze the fabricated mirror surfaces by fitting polynomial functions to the measured data. We accomplish alignment of this two-mirror off-axis system using a ray tracing method. A simple imaging test is performed to compare a pinhole image with a simulated prediction.

  6. A survey report for the biped locomotion robot compensating three-axis moment

    International Nuclear Information System (INIS)

    A dynamic walking simulation of biped locomotion robots based on the Zero Moment Point (ZMP) criterion is being conducted at JAERI. The ZMP criterion to obtain the stable walking patterns is that respective sums of moments around pitch-axis and roll-axis which act on the robot are equal to zero. So far, as for the rest moment around yaw-axis, the moment is balanced to frictional force, assuming that the frictional force between robot's sole and floor is sufficiently large in our study. According to a recent paper, however, slipping around yaw-axis between robot's sole and floor has occurred as the walking speed becomes faster, and the slipping has made the walking unstable. So influence of this moment can not be ignored for the fast walking. A survey has been performed for collecting relevant information from already existing biped locomotion robots. This is a survey report for the biped locomotion robot compensating three-axis moment by a trunk motion: the WL-12RV designed and developed at Waseda University. The WL-12RV has been realized 1.5 times as fast as dynamic walking compared with a biped locomotion robot compensating two-axis moment (e.g. WL-12RIV). This report includes the machine model, control method and results of walking experiments of the WL-12RV. (author)

  7. GRB off-axis afterglows and the emission from the accompanying supernovae

    CERN Document Server

    Kathirgamaraju, Adithan; Giannios, Dimitrios

    2016-01-01

    Gamma-Ray Burst (GRB) afterglows are likely produced in the shock that is driven as the GRB jet interacts with the external medium. Long duration GRBs are also associated with powerful supernovae (SN). We consider the optical and radio afterglows of long GRBs for both blasts viewed along the jet axis ("on-axis" afterglows) and misaligned observes ("off-axis" afterglows). Comparing the optical emission from the afterglow with that of the accompanying SN, using SN 1998bw as an archetype, we find that only a few percent of afterglows viewed off-axis are brighter than the SN. For observable optical off-axis afterglows the viewing angle is at most twice the half-opening angle of the GRB jet. Radio off-axis afterglows should be detected with upcoming radio surveys within a few hundred Mpc. We propose that these surveys will act as "radio triggers," and that dedicated radio facilities should follow-up these sources. Follow-ups can unveil the presence of the radio supernova remnant, if present. In addition, they can ...

  8. Design and implementation of five-axis transformation function in CNC system

    Directory of Open Access Journals (Sweden)

    Wang Feng

    2014-04-01

    Full Text Available To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle-tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP (rotation tool center point control and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software structure, the instructions with respect to the cutter’s position and orientation can be directly carried out in the CNC system.

  9. Nanoscratch Characterization of GaN Epilayers on c- and a-Axis Sapphire Substrates

    Directory of Open Access Journals (Sweden)

    Wen Hua-Chiang

    2010-01-01

    Full Text Available Abstract In this study, we used metal organic chemical vapor deposition to form gallium nitride (GaN epilayers on c- and a-axis sapphire substrates and then used the nanoscratch technique and atomic force microscopy (AFM to determine the nanotribological behavior and deformation characteristics of the GaN epilayers, respectively. The AFM morphological studies revealed that pile-up phenomena occurred on both sides of the scratches formed on the GaN epilayers. It is suggested that cracking dominates in the case of GaN epilayers while ploughing during the process of scratching; the appearances of the scratched surfaces were significantly different for the GaN epilayers on the c- and a-axis sapphire substrates. In addition, compared to the c-axis substrate, we obtained higher values of the coefficient of friction (μ and deeper penetration of the scratches on the GaN a-axis sapphire sample when we set the ramped force at 4,000 μN. This discrepancy suggests that GaN epilayers grown on c-axis sapphire have higher shear resistances than those formed on a-axis sapphire. The occurrence of pile-up events indicates that the generation and motion of individual dislocation, which we measured under the sites of critical brittle transitions of the scratch track, resulted in ductile and/or brittle properties as a result of the deformed and strain-hardened lattice structure.

  10. Evolution of hypothalamus-pituitary growth axis among fish, amphibian, birds and mammals

    Directory of Open Access Journals (Sweden)

    Moaeen-Ud-Din M.

    2015-01-01

    Full Text Available Hypothalamus-pituitary growth axis (HP growth axis regulates animal growth and development in pre-natal and post natal life governed by many factors. However, until recently, the evolutionary history of this axis among lineages is not understood. Aim of the present study was to understand the major events in evolution and evolutionary history and trend of HP growth axis. The diversity among Homo sapience, Mus musculus, Rattus norvegicus, Gallus gallus, Danio rerio and Xenopus laevis was determined for genes involved in HP growth axis in current study. Sequences of HP growth axis genes were retrieved from NCBI (http://www.ncbi.nlm.nih.gov/. Nucleotide diversity using Kimura’s two-parameter method; codon-based test of positive selection using the Nei-Gojobori; equality of evolutionary rate with Tajima's relative rate test and phylogenetic history using the RelTime method were estimated in MEGA6. Estimates of the coefficients of evolutionary differentiation based on nucleotides and amino acids substitution patterns of HP growth axis genes showed contrasting evolutionary patterns among the lineages. The results demonstrated that although these genes might have crucial functional roles in each of the species, however, their sequence divergence did not necessarily reflect similar molecular evolution among the species. Codon-based test of positive selection revealed that Human vs Mouse, Chicken vs Rat, Human vs Rat and Mouse vs Rat had similar and higher non synonymous substitutions (P > 0.05. Higher rate of non-synonymous substitutions at similar orthologs level among species indicated a similar positive selection pressure in these species. Results for relative rate test assessed with the chi-squared test showed difference on unique mutations among lineages at synonymous and non synonymous sites except Chicken vs Mouse, Human vs Mouse, Chicken vs Rat, Human vs Rat and Mouse vs Rat. This indicated that the mutagenic process that generates

  11. The different roles of glucocorticoids in the hippocampus and hypothalamus in chronic stress-induced HPA axis hyperactivity.

    Directory of Open Access Journals (Sweden)

    Li-Juan Zhu

    Full Text Available Hypothalamus-pituitary-adrenal (HPA hyperactivity is observed in many patients suffering from depression and the mechanism underling the dysfunction of HPA axis is not well understood. Chronic stress has a causal relationship with the hyperactivity of HPA axis. Stress induces the over-synthesis of glucocorticoids, which will arrive at all the body containing the brain. It is still complicated whether glucocorticoids account for chronic stress-induced HPA axis hyperactivity and in which part of the brain the glucocorticoids account for chronic stress-induced HPA axis hyperactivity. Here, we demonstrated that glucocorticoids were indispensable and sufficient for chronic stress-induced hyperactivity of HPA axis. Although acute glucocorticoids elevation in the hippocampus and hypothalamus exerted a negative regulation of HPA axis, we found that chronic glucocorticoids elevation in the hippocampus but not in the hypothalamus accounted for chronic stress-induced hyperactivity of HPA axis. Chronic glucocorticoids exposure in the hypothalamus still exerted a negative regulation of HPA axis activity. More importantly, we found mineralocorticoid receptor (MR - neuronal nitric oxide synthesis enzyme (nNOS - nitric oxide (NO pathway mediated the different roles of glucocorticoids in the hippocampus and hypothalamus in regulating HPA axis activity. This study suggests that the glucocorticoids in the hippocampus play an important role in the development of HPA axis hyperactivity and the glucocorticoids in the hypothalamus can't induce hyperactivity of HPA axis, revealing new insights into understanding the mechanism of depression.

  12. The use of a beryllium Hopkinson bar to characterize in-axis and cross-axis accelerometer response in shock environments

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, V.I.; Brown, F.A.

    1997-05-01

    The characteristics of a piezoresistive accelerometer in shock environments are being studied at Sandia National Laboratories in the Mechanical Shock Testing Laboratory. A beryllium Hopkinson bar capability has been developed to extend the understanding of the piezoresistive accelerometer, in two mechanical configurations and with and without mechanical isolation, in the high frequency, high shock environments where measurements are being made. In this paper, recent measurements with beryllium single and split-Hopkinson bar configurations are described. The in axis performance of the piezoresistive accelerometer in mechanical isolation for frequencies of dc-30 kHz and shock magnitudes of up to 6,000 g as determined from measurements with a beryllium Hopkinson bar with a certified laser doppler vibrometer as the reference measurement are presented. Results of characterizations of the accelerometers subjected to cross axis shocks in a split beryllium Hopkinson bar configuration are also presented.

  13. Dosimetric analysis of intact breast irradiation in off-axis planes

    International Nuclear Information System (INIS)

    Purpose/Objective: The purpose of this investigation is to quantify dose inhomogeneity of intact breast irradiation in off-axis planes, and determine how dose inhomogeneity varies according to patient breast size and anatomical region of the breast. Methods and Materials: Eleven patients treated with intact breast radiation underwent a treatment-planning computer tomography (CT) scan with 1-cm slices through the entire breast. The area of breast tissue was defined on each CT slice. Treatment planning with lung correction factors was performed using a two-dimensional treatment-planning system that calculates off-axis dose distributions on a slice-by-slice basis. Each plan utilized tangential beams with matched non divergent posterior borders and with collimator rotation to match the chest wall slope. Dose inhomogeneity within the central plane was minimized during treatment planning by the use of a wedge on the lateral tangent field and by the differential weighting of fields. Dose was normalized at the breast and pectoralis major interface at mid separation in the central plane. Off-axis dose inhomogeneity was not considered in the optimization of the treatment plan. Dose distributions were plotted for each 1-cm slice, and the area of each isodose curve within the breast on each CT slice was calculated. The results of each slice were summed to give an approximation of dose-volume relationships. Results: For the entire population, an average of 10% of the breast volume (range 1-40%) received 110% or greater of the prescribed dose. Increasing dose inhomogeneity was positively correlated with increasing breast sizes (r 0.72, p = 0.01--Spearmen rank test). Analysis of dose as a function of location within the breast, revealed that the greatest dose inhomogeneity occurred in the lower anatomical quadrants of the breast (p 0.003--Kruskal-Wallis test). For the group, the mean breast volume that received a 110% or greater dose was: 30% at 6 cm below central axis, 14% at 4

  14. Determination of Flux-Gate Magnetometer Spin Axis Offsets with the Electron Drift Instrument

    Science.gov (United States)

    Plaschke, Ferdinand; Nakamura, Rumi; Giner, Lukas; Teubenbacher, Robert; Chutter, Mark; Leinweber, Hannes K.; Magnes, Werner

    2014-05-01

    Spin-stabilization of spacecraft enormously supports the in-flight calibration of onboard flux-gate magnetometers (FGMs): eight out of twelve calibration parameters can be determined by minimization of spin tone and harmonics in the calibrated magnetic field measurements. From the remaining four parameters, the spin axis offset is usually obtained by analyzing observations of Alfvénic fluctuations in the solar wind. If solar wind measurements are unavailable, other methods for spin axis offset determination need to be used. We present two alternative methods that are based on the comparison of FGM and electron drift instrument (EDI) data: (1) EDI measures the gyration periods of instrument-emitted electrons in the ambient magnetic field. They are inversely proportional to the magnetic field strength. Differences between FGM and EDI measured field strengths can be attributed to inaccuracies in spin axis offset, if the other calibration parameters are accurately known. (2) For EDI electrons to return to the spacecraft, they have to be sent out in perpendicular direction to the ambient magnetic field. Minimization of the variance of electron beam directions with respect to the FGM-determined magnetic field direction also yields an estimate of the spin axis offset. Prior to spin axis offset determination, systematic inaccuracies in EDI gyration period measurements and in the transformation of EDI beam directions into the FGM spin-aligned reference coordinate system have to be corrected. We show how this can be done by FGM/EDI data comparison, as well.

  15. AXIS: an instrument for imaging Compton radiographs using the Advanced Radiography Capability on the NIF.

    Science.gov (United States)

    Hall, G N; Izumi, N; Tommasini, R; Carpenter, A C; Palmer, N E; Zacharias, R; Felker, B; Holder, J P; Allen, F V; Bell, P M; Bradley, D; Montesanti, R; Landen, O L

    2014-11-01

    Compton radiography is an important diagnostic for Inertial Confinement Fusion (ICF), as it provides a means to measure the density and asymmetries of the DT fuel in an ICF capsule near the time of peak compression. The AXIS instrument (ARC (Advanced Radiography Capability) X-ray Imaging System) is a gated detector in development for the National Ignition Facility (NIF), and will initially be capable of recording two Compton radiographs during a single NIF shot. The principal reason for the development of AXIS is the requirement for significantly improved detection quantum efficiency (DQE) at high x-ray energies. AXIS will be the detector for Compton radiography driven by the ARC laser, which will be used to produce Bremsstrahlung X-ray backlighter sources over the range of 50 keV-200 keV for this purpose. It is expected that AXIS will be capable of recording these high-energy x-rays with a DQE several times greater than other X-ray cameras at NIF, as well as providing a much larger field of view of the imploded capsule. AXIS will therefore provide an image with larger signal-to-noise that will allow the density and distribution of the compressed DT fuel to be measured with significantly greater accuracy as ICF experiments are tuned for ignition. PMID:25430200

  16. Influence of Off-axis Neutral Beam Injection on Resistive Wall Mode Stability

    International Nuclear Information System (INIS)

    Full text: The stabilization of the resistive wall mode (RWM) is an essential issue for future magnetic fusion reactors (e.g., ITER) aiming at long-duration steady discharges over the no-wall beta limit. The RWM has been extensively investigated during recent years, both theoretically and experimentally. However, so far the physical mechanism of the passive control of the RWM has not been investigated fully, particularly the mechanism for the interaction between the RWM and energetic particles (EPs). Recent experiments in DIII-D indicate that the increase of the off-axis neutral beam injection (NBI) power can lead to the enhancement of RWM stability, which is opposite to expectation from consideration of the trapped particles fraction reduced by off-axis NBI. In this work, we apply our previous theory model to investigate the deposition effect of trapped EPs from off-axis NBI on the RWM instability. The results show that the spatial deposition effect of trapped EPs indeed significantly affects the RWM stability, and, compared with the on-axis case, off-axis deposition of EPs can contribute more stabilization to the RWM. (author)

  17. Programming of the hypothalamic-pituitary-interrenal axis by maternal social status in zebrafish (Danio rerio).

    Science.gov (United States)

    Jeffrey, Jennifer D; Gilmour, Kathleen M

    2016-06-01

    The present study examined the effects of maternal social status, with subordinate status being a chronic stressor, on development and activity of the stress axis in zebrafish embryos and larvae. Female zebrafish were confined in pairs for 48 h to establish dominant/subordinate hierarchies; their offspring were reared to 144 h post-fertilization (hpf) and sampled at five time points over development. No differences were detected in maternal cortisol contribution, which is thought to be an important programmer of offspring phenotype. However, once zebrafish offspring began to synthesize cortisol de novo (48 hpf), larvae of dominant females exhibited significantly lower baseline cortisol levels than offspring of subordinate females. These lower cortisol levels may reflect reduced hypothalamic-pituitary-interrenal (HPI) axis activity, because corticotropin-releasing factor (crf) and cytochrome p450 side chain cleavage enzyme (p450scc) mRNA levels also were lower in larvae from dominant females. Moreover, baseline mRNA levels of HPI axis genes continued to be affected by maternal social status beyond 48 hpf. At 144 hpf, stress-induced cortisol levels were significantly lower in offspring of subordinate females. These results suggest programming of stress axis function in zebrafish offspring by maternal social status, emphasizing the importance of maternal environment and experience on offspring stress axis activity. PMID:27045091

  18. Analysis of wind turbine blade behavior under static dual axis loads

    Energy Technology Data Exchange (ETDEWEB)

    Son, Byung Jik [Korea Univ., Seoul (Korea, Republic of); Huh, Yong Hak; Kim, Dong Jin; Kim, Jong Il [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2012-03-15

    For the assessment of the performance of a wind turbine blade, a simulated loading test may be required. In this study, the blade behavior was investigated through numerical analysis using a dual axis loading test, closely simulating the real operation conditions. The blade structure for the 100 kw class wind turbine system was modeled using the finite element (FE) program ANSYS. The failure criteria and buckling analysis under dual axis loading were examined. The failure analysis, including fiber failure and inter fiber failure, was performed with Puck's failure criterion. As the dual axis load ratio increases, the relatively increased stress occurs at the trailing edge and skin surface 3300-3600mm away from the root. Furthermore, it is revealed that increasing the dual axis load ratio makes the location that is weakest against buckling move toward the root part. Thus, it is seen that the dual axis load test may be an essential requirement for the verification of blade performance.

  19. Adaptive sliding mode control of the A-axis used for blisk manufacturing

    Directory of Open Access Journals (Sweden)

    Zhao Pengbing

    2014-06-01

    Full Text Available As a key assembly in the 5-axis CNC machine tools, positioning precision of the A-axis directly affects the machining accuracy and surface quality of the parts. First of all, mechanical structure and control system of the A-axis are designed. Then, considering the influence of nonlinear friction, backlash, unmodeled dynamics, uncertain cutting force and other external disturbance on the control precision of the A-axis, an adaptive sliding mode control (ASMC based on extended state observer (ESO is proposed. ESO is employed to estimate the state variables of the unknown system and an adaptive law is adopted to compensate for the input dead-zone caused by friction, backlash and other nonlinear characteristics. Finally, stability of the closed-loop system is guaranteed by the Lyapunov theory. Positioning experiments illustrate the perfect estimation of ESO and the stronger anti-interference and robustness of ASMC, which can improve the control precision of the A-axis by about 40 times. Processing experiments show that the ASMC can reduce the waviness, average error and roughness of the processed surface by 35.63%, 31.31% and 30.35%, respectively.

  20. Adaptive sliding mode control of the A-axis used for blisk manufacturing

    Institute of Scientific and Technical Information of China (English)

    Zhao Pengbing; Shi Yaoyao

    2014-01-01

    As a key assembly in the 5-axis CNC machine tools, positioning precision of the A-axis directly affects the machining accuracy and surface quality of the parts. First of all, mechanical structure and control system of the A-axis are designed. Then, considering the influence of nonlin-ear friction, backlash, unmodeled dynamics, uncertain cutting force and other external disturbance on the control precision of the A-axis, an adaptive sliding mode control (ASMC) based on extended state observer (ESO) is proposed. ESO is employed to estimate the state variables of the unknown system and an adaptive law is adopted to compensate for the input dead-zone caused by friction, backlash and other nonlinear characteristics. Finally, stability of the closed-loop system is guaran-teed by the Lyapunov theory. Positioning experiments illustrate the perfect estimation of ESO and the stronger anti-interference and robustness of ASMC, which can improve the control precision of the A-axis by about 40 times. Processing experiments show that the ASMC can reduce the waviness, average error and roughness of the processed surface by 35.63%, 31.31%and 30.35%, respectively.

  1. Broadband quantitative phase microscopy with extended field of view using off-axis interferometric multiplexing.

    Science.gov (United States)

    Girshovitz, Pinhas; Frenklach, Irena; Shaked, Natan T

    2015-11-01

    We propose a new portable imaging configuration that can double the field of view (FOV) of existing off-axis interferometric imaging setups, including broadband off-axis interferometers. This configuration is attached at the output port of the off-axis interferometer and optically creates a multiplexed interferogram on the digital camera, which is composed of two off-axis interferograms with straight fringes at orthogonal directions. Each of these interferograms contains a different FOV of the imaged sample. Due to the separation of these two FOVs in the spatial-frequency domain, they can be fully reconstructed separately, while obtaining two complex wavefronts from the sample at once. Since the optically multiplexed off-axis interferogram is recorded by the camera in a single exposure, fast dynamics can be recorded with a doubled imaging area. We used this technique for quantitative phase microscopy of biological samples with extended FOV. We demonstrate attaching the proposed module to a diffractive phase microscopy interferometer, illuminated by a broadband light source. The biological samples used for the experimental demonstrations include microscopic diatom shells, cancer cells, and flowing blood cells. PMID:26440914

  2. Simulation and experimental verification of nanoscale motion in a 2-axis quasi-passive platform

    Science.gov (United States)

    Li, Biao; Zhu, Yu; Sharon, Andre

    2007-08-01

    As leading edge technology pursues a common trend of working on smaller and smaller scales, there is increasing demand on motion management at the nanometer range. We previously reported a 1-axis quasi-passive platform with nanoscale alignment tolerance (Li et al 2005 J. Microelectromech. Syst. 14 1339-46). This paper presents our research on a 2-axis positioning platform capable of four degrees-of-freedom in-plane motion. The concept comprises a platform suspended by tensile stressed flexure elements on either side. Finite-element simulation shows that translation is achieved by cutting pairs of stress elements that are symmetrical to the x- or y-axis (axis-symmetrically cut), while angular motion is achieved by cutting pairs of stress elements that are symmetrical to the center point of the platform (center-point-symmetrically cut). Focused ion beam experiments demonstrate that such a platform enables positioning accuracy in the order of tens of nanometers. Variable-temperature scanning electron microscopy demonstrates that temperature variation modifies the platform position at a rate of 0.81 nm °C-1 for a platform with only three support stress elements at each side. Finally, we have performed fiber coupling experiments using an automated control program, and have demonstrated optimized coupling efficiency using the 2-axis device. A portion of the paper appeared at Hiltonhead 2006.

  3. A Wavelet Bicoherence-Based Quadratic Nonlinearity Feature for Translational Axis Condition Monitoring

    Directory of Open Access Journals (Sweden)

    Yong Li

    2014-01-01

    Full Text Available The translational axis is one of the most important subsystems in modern machine tools, as its degradation may result in the loss of the product qualification and lower the control precision. Condition-based maintenance (CBM has been considered as one of the advanced maintenance schemes to achieve effective, reliable and cost-effective operation of machine systems, however, current vibration-based maintenance schemes cannot be employed directly in the translational axis system, due to its complex structure and the inefficiency of commonly used condition monitoring features. In this paper, a wavelet bicoherence-based quadratic nonlinearity feature is proposed for translational axis condition monitoring by using the torque signature of the drive servomotor. Firstly, the quadratic nonlinearity of the servomotor torque signature is discussed, and then, a biphase randomization wavelet bicoherence is introduced for its quadratic nonlinear detection. On this basis, a quadratic nonlinearity feature is proposed for condition monitoring of the translational axis. The properties of the proposed quadratic nonlinearity feature are investigated by simulations. Subsequently, this feature is applied to the real-world servomotor torque data collected from the X-axis on a high precision vertical machining centre. All the results show that the performance of the proposed feature is much better than that of original condition monitoring features.

  4. The technical method of geometric error measurement for multi-axis NC machine tool by laser tracker

    International Nuclear Information System (INIS)

    The machining accuracy is an important index to evaluate the machine tool characteristics, and error measurement and compensation are effective methods to improve the machining accuracy with low cost. Error measurement is a prerequisite and basis for error compensation, so how to quickly and accurately measure the machine error is particularly important. To quickly and accurately detect the geometric error of multi-axis NC machine tool, a new method with laser tracker based on the sequential multi-lateration measurement principle is proposed in the paper. The laser tracker is used to measure the same motion trajectory of the linear axis and rotary axis of machine tool at different base stations. Based on the GPS principle, the space coordinates of each measuring point can be determined by large amount of measured data. Then according to the error model of the linear axis and rotary axis, each error can be separated. In the paper, the principles of sequential multi-lateration measurement are analyzed in depth. By establishing the mathematical model of sequential multi-lateration measurement for the linear axis and rotary axis, the algorithms for linear axis measurement and rotary axis measurement are derived and proved feasible by simulations, respectively. Meanwhile, the error separation algorithm is also deduced. The results of experiments show that this method can achieve quick and accurate detection of errors in multi-axis NC machine tool. (paper)

  5. Analytical Modeling of Squeeze Film Damping in Dual Axis Torsion Microactuators

    Science.gov (United States)

    Moeenfard, Hamid

    2015-10-01

    In this paper, problem of squeeze film damping in dual axis torsion microactuators is modeled and closed form expressions are provided for damping torques around tilting axes of the actuator. The Reynolds equation which governs the pressure distribution underneath the actuator is linearized. The resulting equation is then solved analytically. The obtained pressure distribution is used to calculate the normalized damping torques around tilting axes of the actuator. Dependence of the damping torques on the design parameters of the dual axis torsion actuator is studied. It is observed that with proper selection of the actuator's aspect ratio, damping torque along one of the tilting directions can be eliminated. It is shown that when the tilting angles of the actuator are small, squeeze film damping would act like a linear viscous damping. The results of this paper can be used for accurate dynamical modeling and control of torsion dual axis microactuators.

  6. A new robust gradient-based method for detection of symmetry axis

    Science.gov (United States)

    Hu, Jing; Wan, Qinqi; Hu, Yongli

    2015-12-01

    Symmetry axis extraction is an important part of the image feature detection. So far, various classical symmetry axes extraction algorithms have been proposed, such as the minimum-inertia-axis-based method, the SIFT-based method. If the input image is blurry, or it's difficult to extract feature points or corner points from input images, however, the above algorithms are difficult to obtain satisfied results. This paper presents a gradient-based method that can robustly extract symmetry axis from visual pattern. The key points of our methods are gradient calculation, symmetric weight calculation, and Hough Transform. Our method was evaluated on several datasets, including both blurred and smooth-edged cases. Experimental results demonstrated that our method achieves a more robust performance than previous methods.

  7. Inter-relation between autonomic and HPA axis activity in children and adolescents.

    Science.gov (United States)

    Rotenberg, Sivan; McGrath, Jennifer J

    2016-05-01

    Stress research in youth typically considers either the autonomic nervous system or HPA axis. However, these systems are highly coordinated and physically interconnected. We examined whether the inter-relation between cardio-autonomic and HPA axis measures was better associated with perceived stress than their singular associations. Children and adolescents (N=201) collected saliva samples to measure cortisol (AUCAG, AUCI, maximum), wore an electrocardiogram monitor for 24h to derive heart rate variability (HRV; LF, HF, LF/HF ratio), and completed the Perceived Stress Scale. The interaction between sympathovagal modulation (LF, LF/HF ratio) and cortisol awakening response (AUCAG, AUCI, maximum) explained significantly greater variance in perceived stress than either stress system alone. Higher sympathovagal modulation combined with higher cortisol awakening response was associated with greater perceived stress. Findings suggest that the inter-relation between cardio-autonomic and HPA axis activity may advance our understanding of how stress impacts health. PMID:26835595

  8. Research on the 2-axis cup-wheel dressing technology of arc-diamond grinding wheel

    Science.gov (United States)

    Chang, X. L.; Wu, H. Y.; Peng, Y. F.

    2014-08-01

    The precision dressing of arc-diamond wheel is very hard, expensive and time-consuming because of the super-hard diamond particles and complicated geometrical shape. This paper aims to investigate the cup-wheel dressing technology to realize the high-efficiency regeneration of the arc-diamond wheel. A two-axis cup-wheel dressing technique for precision dressing arc-diamond wheel was suggested and tested. The dressing mechanism of 2-axis cup-wheel was studied. The dressing algorithm and error compensation method were further investigated to improve the dressing precision and efficiency. The experimental results show that the 2-axis cup-wheel dressing technique is valid and applicable to realize the precision dressing of arc-diamond wheel. The machined optical surface condition was apparently improved with the cup-wheel dressed diamond wheel and even became much better when the error compensation algorithm was performed on the arc-diamond wheel.

  9. Tooth brushing pattern classification using three-axis accelerometer and magnetic sensor for smart toothbrush.

    Science.gov (United States)

    Lee, Kang-Hwi; Lee, Jeong-Whan; Kim, Kyeong-Seop; Kim, Dong-Jun; Kim, Kyungho; Yang, Heui-Kyung; Jeong, Keesam; Lee, Byungchae

    2007-01-01

    The concept of intelligent toothbrush, capable of monitoring brushing motion, orientation through the grip axis, during toothbrushing was suggested in our previous study. In this study, we describe a tooth brushing pattern classification algorithm using three-axis accelerometer and three-axis magnetic sensor. We have found that inappropriate tooth brushing pattern showed specific moving patterns. In order to trace the position and orientation of toothbrush in a mouth, we need to know absolute coordinate information of toothbrush. By applying tilt-compensated azimuth (heading) calculation algorithm, which is generally used in small telematics devices, we could find the inclination and orientation information of toothbrush. To assess the feasibility of the proposed algorithm, 8 brushing patterns were preformed by 6 individual healthy subjects. The proposed algorithm showed the detection ratio of 98%. This study showed that the proposed monitoring system was conceived to aid dental care personnel in patient education and instruction in oral hygiene regarding brushing style. PMID:18002931

  10. Towards automatic alignment of a crystalline sample in an electron microscope along a zone axis

    International Nuclear Information System (INIS)

    A method is presented to use an electron microscope in transmission mode to determine the mis-tilt from a zone axis of a crystalline material. The method involves recording a number of additional diffraction patterns with incident beams tilted over 2 to 3 degrees. It is shown that an accuracy of 0.02 degree can be achieved, which is far better than that of the specimen-stage tilt axes, which is about 0.1 degree for the β-tilt. - Highlights: ► Beam tilt can be used to determine accurate mis-orientation from the zone-axis. ► The accuracy of the determined tilt is tunable according need down to 0.02 degrees. ► The presented method may lead the way to automatic zone-axis orientation

  11. Dynamic Analysis of a Floating Vertical Axis Wind Turbine Under Emergency Shutdown Using Hydrodynamic Brake

    DEFF Research Database (Denmark)

    Wang, K.; Hansen, Martin Otto Laver; Moan, T.

    2014-01-01

    Emergency shutdown is always a challenge for an operating vertical axis wind turbine. A 5-MW vertical axis wind turbine with a Darrieus rotor mounted on a semi-submersible support structure was examined in this study. Coupled non-linear aero-hydro-servo-elastic simulations of the floating vertical...... axis wind turbine were carried out for emergency shutdown cases over a range of environmental conditions based on correlated wind and wave data. When generator failure happens, a brake should be applied to stop the acceleration of the rotor to prevent the rotor from overspeeding and subsequent disaster....... In addition to the traditional mechanical brake, a novel hydrodynamic brake was presented to apply to the shutdown case. The effects of the hydrodynamic brake on the platform motions and structural loads under normal operating conditions and during the emergency shutdown events were evaluated. The...

  12. Nonparaxial propagation of a vectorial apertured off-axis Lorentz beam

    Institute of Scientific and Technical Information of China (English)

    Zhou Guo-Quan

    2009-01-01

    Based on the vectorial Rayleigh-Sommerfeld integral formula and the complex Gaussian expansion of the hard-edge aperture function, an analytical propagation expression for a nonparaxial vectorial off-axis Lorentz beam passing through a rectangular aperture is derived. The unapertured case, the far field expression and the scalar paraxial result are also presented as special cases of the general formulae, respectively. Some numerical examples are also given to show the propagation characteristics of a nonparaxial vectorial off-axis Lorentz beam through a rectangular aperture. It is indicated that the f parameter, the off-axis displacement and the truncation parameter all play an important role in determining nonparaxial propagation behaviour.

  13. Adaptive Monte Carlo applied to uncertainty estimation in a five axis machine tool link errors identification

    CERN Document Server

    Andolfatto, Loïc; Lavernhe, Sylvain; 10.1016/j.ijmachtools.2011.03.006

    2011-01-01

    Knowledge of a machine tool axis to axis location errors allows compensation and correcting actions to be taken to enhance its volumetric accuracy. Several procedures exist, involving either lengthy individual test for each geometric error or faster single tests to identify all errors at once. This study focuses on the closed kinematic Cartesian chain method which uses a single setup test to identify the eight link errors of a five axis machine tool. The identification is based on volumetric error measurements for different poses with a non-contact measuring instrument called CapBall, developed in house. In order to evaluate the uncertainty on each identified error, a multi-output Monte Carlo approach is implemented. Uncertainty sources in the measurement and identification chain - such as sensors output, machine drift and frame transformation uncertainties - can be included in the model and propagated to the identified errors. The estimated uncertainties are finally compared to experimental results to assess...

  14. Neuromedins U and S involvement in the regulation of the hypothalamo - pituitary - adrenal axis.

    Directory of Open Access Journals (Sweden)

    Ludwik K. Malendowicz

    2012-12-01

    Full Text Available Abstract: We reviewed neuromedin U (NMU and neuromedin S (NMS involvement in the regulation of the hypothalamo - pituitary - adrenal (HPA axis function. NMU and NMS are structurally related and highly conserved neuropeptides. They exert biological effects via two GPCR receptors designated as NMUR1 and NMUR2 which show differential expression. NMUR1 is expressed predominantly at the periphery, while NMUR2 in the central nervous system. Elements of the NMU/NMS and their receptors network are also expressed in the HPA axis and progress in molecular biology techniques provided new information on their actions within this system. Several lines of evidence suggest that within the HPA axis NMU and NMS act at both hypothalamic and adrenal levels. Moreover, new data suggest that NMU and NMS are involved in central and peripheral control of the stress response.

  15. [Study on the bias axis stress-strain relationship of the human mandible].

    Science.gov (United States)

    Chen, X; Zhao, Y

    1991-06-01

    This paper presents our study on the bias axis elastic properties of the human mandible. The elastic coefficients were determined by the composite materials mechanical testing methods. From these values the "technical constants" were calculated to be: EL = 18.823GPa, ET = 12.777GPa, GLT = 5.564GPa, vLT = 0.302, vTL = 0.205. Variation of elastic constants of the human mandible with the orientation to its long axis was investigated. A brief description of the variation law is given. The bias axis stress-strain relationship of the human mandible is established. The data indicate that the human mandible is a living, anisotropic and nonhomogeneous composite biomaterial. Its mechanical properties have a close relation to its location, orientation and structure. PMID:1786953

  16. [Age-related changes of the hypothalamic-pituitary-adrenal axis: experimental studies in primates].

    Science.gov (United States)

    Goncharova, N D

    2014-01-01

    The article presents a review of the results of the author's works that examine the character of age-related changes of the hypothalamic-pituitary-adrenal (HPA) axis in primates during aging in basal conditions, including disturbances of its circadian rhythms and in conditions of its inhibition and activation by specific stimuli. In addition, the original data are presented on the peculiarities of the HPA axis functioning under acute psycho-emotional stress taking into account the time of day and individual features of the adaptive behavior of animals, severe chronic stress caused by hemoblastosis process and repeated mild psycho-emotional stress impact. Age disturbances in the HPA axis functioning are of pathophysiological significance for the development of stress- and age-related pathologies and progression of the aging process. Individuals with depression adaptive behavior are most vulnerable to stress and pathological aging. PMID:25306658

  17. Forced vibration analysis of rotating structures with application to vertical axis wind turbines

    Science.gov (United States)

    Lobitz, D. W.

    Predictive methods for the dynamic analysis of wind turbine systems are important for assessing overall structural integrity and fatigue life. For the former, the identification of resonance points (spectral analysis) is of primary concern. For the latter forced vibration analysis is necessary. These analyses are complicated by the fact that, for a spinning turbine, the stress-producing deformations take place in both fixed and rotating reference systems simultaneously. As an example, the tower of a horizontal axis wind turbine (HAWT) must be analyzed in a fixed frame, and the rotor in a rotating one. Forced vibration analysis is further complicated in that accurate models need to be developed for aeroload prediction. Methods which are available for forced vibration analysis of both horizontal and vertical axis machines are identified and the method which was developed for vertical axis wind turbines is emphasized, with some comparisons of the predictions to experimental data.

  18. Collective modes and implications for c-axis optical experiments in layered cuprates

    International Nuclear Information System (INIS)

    We address recent experiments in the cuprates which demonstrate a coupling of the c-axis plasma excitation to the superconducting order parameter within a matrix Green's-function formulation. An essential motivation of this work is the premise that a complete unraveling of the order-parameter symmetry cannot be limited to studies of the ab-plane electromagnetic properties; it must also involve the behavior along the c axis. Our gauge-invariant formalism for the electromagnetic response of a superconductor is reviewed and the coupling between collective modes and impurity scattering emphasized. The effects on the behavior of the real component of the dielectric function are found to be relatively more sensitive to the presence of inelastic scattering than to the details of the order-parameter symmetry. Future experiments are suggested which probe the (c-axis) order-parameter collective-mode structure through measurements of the finite wave-vector longitudinal dielectric function

  19. Design of a dual-axis optoelectronic level for precision angle measurements

    International Nuclear Information System (INIS)

    The accuracy of machine tools is mainly determined by angular errors during linear motion according to the well-known Abbe principle. Precision angle measurement is important to precision machines. This paper presents the theory and experiments of a new dual-axis optoelectronic level with low cost and high precision. The system adopts a commercial DVD pickup head as the angle sensor in association with the double-layer pendulum mechanism for two-axis swings, respectively. In data processing with a microprocessor, the measured angles of both axes can be displayed on an LCD or exported to an external PC. Calibrated by a triple-beam laser angular interferometer, the error of the dual-axis optoelectronic level is better than ±0.7 arcsec in the measuring range of ±30 arcsec, and the settling time is within 0.5 s. Experiments show the applicability to the inspection of precision machines

  20. Development of five axis robotic system for an industrial neutron tomography imaging system

    International Nuclear Information System (INIS)

    Tomography is one of the latest techniques in the field of nondestructive testing. X-rays, gamma rays or neutrons are used as an energy source whereas five axis manipulator is designed to move the specimen across the beam. The 5 axis robotic system has been indigenously developed, designed, manufactured and tested to move up to 10 kg payload. Computer is necessary to process and store data and retrieve it for processing. The same computer is used for control of manipulator. Computer aided tomography is carried out for research and industrial use. Neutron beam will be used either for evaluation of organic materials in attenuation based measurements or for evaluation on the basis of neutron activation of materials like nuclear fuels. The paper describes the indigenously developed 5-axis robotic system as a part of a facility built around Kamini reactor at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam. (author). 4 figs

  1. Active Blade Pitch Control for Straight Bladed Darrieus Vertical Axis Wind Turbine of New Design

    DEFF Research Database (Denmark)

    Chougule, Prasad; Nielsen, Søren R.K.; Basu, Biswajit

    As Development of small vertical axis wind turbines (VAWT) for urban use is becoming an interesting topic both within industry and academia. However, there are few new designs of vertical axis turbines which are customized for building integration. These are getting importance because they operate...... at low rotational speed producing very less noise during operation, although these are less efficient than Horizontal Axis Wind Turbines (HAWT). The efficiency of a VAWT has been significantly improved by H-Darrieus VAWT design based on double airfoil technology as demonstrated by the authors in a...... multiple stream tube method is used to determine the performance of the H-Darrieus VAWT. The power coefficient is compared with that of a fixed pitch and a variable pitch double airfoil blade VAWT. It is demonstrated that an improvement in power coefficient by 20% is achieved and the turbine could start at...

  2. Vertical-axis rotations determined from paleomagnetism of Mesozoic and Cenozoic strata of the Bolivian Andes

    Science.gov (United States)

    Richards, David R.; Butler, Robert F.; Sempere, Thierry

    2004-07-01

    Thermal demagnetization and principal component analysis allowed determination of characteristic remanent magnetization (ChRM) directions from 256 sites at 22 localities in Mesozoic and Cenozoic sedimentary strata of the Bolivian Altiplano and Eastern Cordillera. An inclination-only fold test of site-mean ChRM directions from Cenozoic units (principally the Santa Lucía Formation) indicates optimum unfolding at 97.1% unfolding, consistent with a primary origin for the ChRM. For Mesozoic strata, optimum unfolding occurred at 89.2%, perhaps indicating secondary remagnetization at some locations. For Cenozoic units, comparison of locality-mean directions with expected paleomagnetic directions indicates vertical-axis rotations from 33° counterclockwise to 24° clockwise. Euler pole analysis of along-strike variation in crustal shortening within the Subandean and Interandean zones indicates 18° clockwise rotation south of the axis of curvature of the Bolivian Andes and 6° counterclockwise rotation northwest of the axis during the past 10 m.y. Along-strike variation of shortening within the Eastern Cordillera indicates 8° clockwise rotation south of the axis and 8° counterclockwise rotation northwest of the axis from 35 to 10 Ma. These vertical-axis rotations produced by along-strike variations in crustal shortening during development of the Bolivian fold-thrust belt agree well with observed rotations determined from paleomagnetism of Cenozoic rocks in the Eastern Cordillera and in the Subandean and Interandean zones. However, local rotations are required to account for complex rotations in the Cochabamba Basin and within the Altiplano. The curvature of the Bolivian Andes has been progressively enhanced during Cenozoic fold-thrust belt deformation.

  3. Neuromedin B stimulates the hypothalamic-pituitary-gonadal axis in male rats.

    Science.gov (United States)

    Boughton, C K; Patel, S A; Thompson, E L; Patterson, M; Curtis, A E; Amin, A; Chen, K; Ghatei, M A; Bloom, S R; Murphy, K G

    2013-11-10

    Neuromedin B (NMB) is a highly conserved bombesin-related peptide found in mammals. NMB mRNA is detected in the central nervous system (CNS) and is highly expressed in the rat hypothalamus, in particular the medial preoptic area and the arcuate nucleus. The mammalian bombesin family of receptors consists of three closely related G protein coupled receptors, BB1, BB2 and BB3. The BB1 receptor subtype has the highest affinity for NMB. NMB has well documented roles in the regulation of the thyroid axis and the stress axis in rats. However, there is little available data regarding the role of NMB in the regulation of the hypothalamic-pituitary-gonadal (HPG) axis. It is known that the NMB receptor is expressed in immortalised gonadotrophin releasing hormone (GnRH) releasing GT1-7 cells and murine forebrain GnRH neurons, and that anterior pituitary NMB-immunoreactivity is altered by changes in the sex steroid environment. The objective of these studies was thus to further investigate the effects of NMB on the HPG axis. Intracerebroventricular (ICV) administration of NMB (10 nmol) to adult male rats significantly increased plasma luteinising hormone (LH) levels 30 min after injection (plasma LH ng/ml; saline 0.69±0.07, 10 nmol NMB 1.33±0.17, P<0.01). In vitro, NMB stimulated GnRH release from hypothalamic explants from male rats and from hypothalamic GT1-7 cells. NMB had no significant effect on LH release from anterior pituitary explants from male rats, or from pituitary LβT2 cells in vitro. These results suggest a previously unreported role for NMB in the stimulation of the HPG axis via hypothalamic GnRH. Further work is now required to determine the receptor mediating the effects of NMB on the reproductive axis and the physiological role of NMB in reproduction. PMID:24120470

  4. Induction of secondary axis in hydra revisited: New insights into pattern formation

    Science.gov (United States)

    Kadu, Vishal; S. Ghaskadbi, Saroj; Ghaskadbi, Surendra

    2012-01-01

    In 1909, several years before the famous `Organizer’ experiments of Spemann and Mangold, Ethel Browne demonstrated induction of a secondary axis in hydra by grafting a hypostome. Based on this and subsequent work, in the late sixties, Lewis Wolpert proposed the theory of morphogen gradients and positional information. We have studied secondary axis induction by hypostome and foot tissue using three species of hydra as well as transgenic, GFP-expressing lines of hydra. We have found that pieces of hypostome and complete foot of a donor hydra can induce a secondary axis all along (in upper, middle or lower parts of) the body column of a host hydra, both within and across species with comparable rates. Thus, contrary to the available literature, our results show that the host hypostome does not completely inhibit the induction of a secondary axis. The length of the induced axis though is determined by the position of the graft. By using GFP-expressing lines of hydra we have demonstrated that host ectodermal and endodermal cells actively contribute to the secondary axis. On comparison, the hypostome was found to be a stronger and dominant Organizer than the foot. Foot grafting experiments show a transient increase in the host length as well as the distance between the two Organizers. The length becomes normal once the grafted foot reaches the budding zone. Our work brings out several new aspects of the role of positional cues in pattern formation in hydra that can be now be explored at cellular and molecular levels. PMID:24551754

  5. Use of the Humphrey Lens Analyzer for off-axis measurements of spectacle lenses.

    Science.gov (United States)

    Atchison, D A; Kris, M; Sheedy, J E; Bailey, I L

    1991-04-01

    Automated focimeters can be used to make quick, precise measurements of off-axis power and prismatic effects corresponding to an eye rotating behind a spectacle lens. An automated focimeter, the Humphrey Lens Analyzer, was assessed in this regard. The Humphrey Lens Analyzer can be used to give a valid measure of off-axis power of lenses with low power, but not of lenses with moderate to higher power (greater than 3 D). For 3 D spherical lenses discrepancies of the order of 0.1 D occur at 30 degrees rotation, and 6 D spheres give discrepancies of 0.5 D at the same rotation. Small discrepancies were found for measurements of prism. The Humphrey Lens Analyzer was also used in a mode where the lens being tested is rotated about the center of curvature of its back surface. This is the mode often used to assess aberrations and prism of progressive-addition lenses. In this mode, the instrument provides reasonable accuracy in estimating off-axis power corresponding to eye rotation for lenses with low power, but not for lenses with moderate to higher power (greater than 3 D). However, it provides accurate values of the variation in off-axis surface power for low powered lenses with aspheric front surfaces. There were considerable systematic errors associated with the measurement of prism. A simple raytracing method was developed to predict the results of measurements with the Humphrey Lens Analyzer. Predictions of off-axis power were good when lenses were rotated about a position corresponding to the center-of-rotation of an eye, but were poorer when lenses were rotated about the center of curvature of their back surfaces. Predictions of primatic efforts were good in both situations. A method by which the Humphrey Lens Analyzer should provide an accurate measurement of off-axis powers corresponding to eye rotation behind a spectacle lens is described, but has not been tested. PMID:2052286

  6. Flexible Piezoelectric Tactile Sensor Array for Dynamic Three-Axis Force Measurement

    Science.gov (United States)

    Yu, Ping; Liu, Weiting; Gu, Chunxin; Cheng, Xiaoying; Fu, Xin

    2016-01-01

    A new flexible piezoelectric tactile sensor array based on polyvinylidene fluoride (PVDF) film is proposed for measuring three-axis dynamic contact force distribution. The array consists of six tactile units arranged as a 3 × 2 matrix with spacing 8 mm between neighbor units. In each unit, a PVDF film is sandwiched between four square-shaped upper electrodes and one square-shaped lower electrode, forming four piezoelectric capacitors. A truncated pyramid bump is located above the four piezoelectric capacitors to improve force transmission. A three-axis contact force transmitted from the top of the bump will lead to the four piezoelectric capacitors underneath undergoing different charge changes, from which the normal and shear components of the force can be calculated. A series of dynamic tests have been carried out by exerting sinusoidal forces with amplitudes ranging from 0 to 0.5 N in the x-axis, 0 to 0.5 N in the y-axis, and 0 to 1.5 N in the z-axis, separately. The tactile units show good sensitivities with 14.93, 14.92, and 6.62 pC/N in the x-, y-, and z-axes, respectively. They can work with good linearity, relatively low coupling effect, high repeatability, and acceptable frequency response in the range of 5–400 Hz to both normal and shear load. In addition, dynamic three-axis force measurement has been conducted for all of the tactile units. The average errors between the applied and calculated forces are 10.68% ± 6.84%. Furthermore, the sensor array can be easily integrated onto a curved surface, such as robotic and prosthetic hands, due to its excellent flexibility. PMID:27271631

  7. Design and implementation of a multi-axis precision movement machine based on MAS theory

    Institute of Scientific and Technical Information of China (English)

    Li MA; Linlin CI; Genyan GE

    2009-01-01

    A model construction of a multi-agent system (MAS) and the basic function of the agent are described.The precision control method using the multi-CPU of a programmable logic controller (PLC) is introduced,and a distributed method using multiple CPUs to control different motion machines is given.The test results indicate that in industrial control fields,the combination of using the credible PLC to control the motion machine and multi-CPU task distributing methods can solve multi-axis machine linkage and implication,providing a more credible method for multi-axis motion units.

  8. Six-axis force–torque sensor with a large range for biomechanical applications

    International Nuclear Information System (INIS)

    A silicon six-axis force–torque sensor is designed and realized to be used for measurement of the power transfer between the human body and the environment. Capacitive read-out is used to detect all axial force components and all torque components simultaneously. Small electrode gaps in combination with mechanical amplification by the sensor structure result in a high sensitivity. The miniature sensor has a wide force range of up to 50 N in normal direction, 10 N in shear direction and 25 N mm of maximum torque around each axis. (paper)

  9. Gravity-related transport in reactive off-axis sputtering deposition?

    International Nuclear Information System (INIS)

    An experiment was performed to investigate the transport characterization of reactive off-axis sputtering deposition. Due to the collision and/or thermalization process between the sputtered species and background gases, three transport regions were observed when the growth pressures were varied from 5 to 150 mTorr. A gravity-related phenomenon was revealed in film growth at relatively high growth pressures by measuring film growth rate at two depositing orientations, which was either parallel or perpendicular to the gravity vector. In this study, possible design for the substrate holder orientation in the off-axis sputtering system was also suggested

  10. Postoperative Astigmatic Outcomes Based on the Haptic Axis of Intraocular Lenses Inserted in Cataract Surgery

    OpenAIRE

    Kim, In-Tae; Park, Hae-Young Lopilly; Kim, Hyun-Seung

    2011-01-01

    Purpose This study was conducted to compare post-operative astigmatic outcomes of two groups, with-the-rule (WTR) and against-the-rule (ATR) astigmatism patients, according to the haptic axis of intraocular lenses (IOLs) inserted in cataract surgery. Methods Seventy-two eyes with WTR astigmatism and 79 eyes with ATR astigmatism had cataract surgery through a clear corneal temporal incision. These two groups of eyes were then each divided into 2 groups based on whether the haptic axis of the i...

  11. Mathematical modeling of the hypothalamic–pituitary–adrenal gland (HPA) axis, including hippocampal mechanisms

    DEFF Research Database (Denmark)

    Andersen, Morten; Vinther, Frank; Ottesen, Johnny T.

    2013-01-01

    curves stay non-negative and bounded, which can be interpreted as a mathematical formulation of homeostasis. No oscillating solutions are present when using physiologically reasonable parameter values. This indicates that the ultradian rhythm originate from different mechanisms.Using physiologically......This paper presents a mathematical model of the HPA axis. The HPA axis consists of the hypothalamus, the pituitary and the adrenal glands in which the three hormones CRH, ACTH and cortisol interact through receptor dynamics. Furthermore, it has been suggested that receptors in the hippocampus have...

  12. On-axis Gaussian beam scattering by an eccentrically coated conducting cylinder

    Science.gov (United States)

    Zhai, Yuman; Sun, Yufa; Zhang, Huayong

    2012-08-01

    Based on the generalized Lorenz-Mie theory (GLMT) framework, an exact analytic solution to electromagnetic scattering by an eccentrically coated conducting cylinder is constructed, for oblique incidence of an on-axis Gaussian beam described by a localized beam model. The solution is found by the classical separation of variables technique and the translational addition theorem. For a tightly focused Gaussian beam propagating perpendicularly to the cylinder axis, numerical results of the normalized differential scattering cross section are presented, and the scattering characteristics are discussed concisely.

  13. Nondispersion polaritons on symmetrically oriented surfaces of two-axis crystals

    International Nuclear Information System (INIS)

    One derived system of dispersion equations describing surface polaritons in optic two-axis crystals on surfaces parallel to symmetry planes of ε permittivity tensor. One analyzes ranges of occurrence, value and orientation of sectors of propagation directions of nondispersion surface polaritons occurring at positive values of ε tensor components. For slightly anisotropic crystals one determined three noncrossing values of dielectric anisotropy parameters where nondispersion polariton may occur. One traced evolution of configuration of optic axis at variation of anisotropy parameters within ranges of occurrence of polaritons

  14. A two-dimensional matrix correction for off-axis portal dose prediction errors

    International Nuclear Information System (INIS)

    Purpose: This study presents a follow-up to a modified calibration procedure for portal dosimetry published by Bailey et al. [“An effective correction algorithm for off-axis portal dosimetry errors,” Med. Phys. 36, 4089–4094 (2009)]. A commercial portal dose prediction system exhibits disagreement of up to 15% (calibrated units) between measured and predicted images as off-axis distance increases. The previous modified calibration procedure accounts for these off-axis effects in most regions of the detecting surface, but is limited by the simplistic assumption of radial symmetry. Methods: We find that a two-dimensional (2D) matrix correction, applied to each calibrated image, accounts for off-axis prediction errors in all regions of the detecting surface, including those still problematic after the radial correction is performed. The correction matrix is calculated by quantitative comparison of predicted and measured images that span the entire detecting surface. The correction matrix was verified for dose-linearity, and its effectiveness was verified on a number of test fields. The 2D correction was employed to retrospectively examine 22 off-axis, asymmetric electronic-compensation breast fields, five intensity-modulated brain fields (moderate-high modulation) manipulated for far off-axis delivery, and 29 intensity-modulated clinical fields of varying complexity in the central portion of the detecting surface. Results: Employing the matrix correction to the off-axis test fields and clinical fields, predicted vs measured portal dose agreement improves by up to 15%, producing up to 10% better agreement than the radial correction in some areas of the detecting surface. Gamma evaluation analyses (3 mm, 3% global, 10% dose threshold) of predicted vs measured portal dose images demonstrate pass rate improvement of up to 75% with the matrix correction, producing pass rates that are up to 30% higher than those resulting from the radial correction technique alone. As

  15. A simplified version of the "Axis of Evil Theorem" for distinct points

    OpenAIRE

    Ceria, Michela

    2012-01-01

    Given a finite set $\\mathbf{X}$ of distinct points, Marinari-Mora's 'Axis of Evil Theorem' states that a combinatorial algorithm and interpolation enable to find a 'linear' factorization for a lexicographical minimal Groebner basis $\\mathcal{G}(I(\\mathbf{X}))$ of the zerodimensional radical ideal $I(\\mathbf{X})$. In this work we provide such algorithm, showing that it ends in a finite number of steps and that it actually provides the correct result. The 'Axis of Evil' algorithm takes as input...

  16. Electron gun with off-axis beam injection for a race-track microtron

    International Nuclear Information System (INIS)

    A miniature 12 MeV race-track microtron for medical applications is under construction at the Technical University of Catalonia in collaboration with several Spanish centers and companies and the Skobeltsyn Institute of Nuclear Physics of the Moscow State University. As a source of electrons a compact 3D on-axis electron gun with an off-axis cathode has been designed to allow a direct and efficient injection into the accelerating structure. Its prototype has been built and successfully tested. Results of the electron gun design simulations and of the prototype performance are herein described.

  17. On the estimation of the magnetic easy axis in pipeline steels using magnetic Barkhausen noise

    Science.gov (United States)

    Martínez-Ortiz, P.; Pérez-Benitez, J. A.; Espina-Hernández, J. H.; Caleyo, F.; Hallen, J. M.

    2015-01-01

    A method for determination of the magnetic easy axis of the Roll Magnetic Anisotropy in API-5L steels is proposed. The method is based on the fact that the angular dependence of the energy corresponding to the main peak of the Magnetic Barkhausen signal presents uniaxial anisotropy with its easy axis parallel to the rolling direction, independently of the angular dependence of the magnetocrystalline energy in the materials. The proposal is also justified based on the analysis of the influence of microstructural changes, produced by hot-rolling on the domain wall dynamics.

  18. FSH and TSH in the Regulation of Bone Mass: The Pituitary/Immune/Bone Axis

    OpenAIRE

    Graziana Colaianni; Concetta Cuscito; Silvia Colucci

    2013-01-01

    Recent evidences have highlighted that the pituitary hormones have profound effects on bone, so that the pituitary-bone axis is now becoming an important issue in the skeletal biology. Here, we discuss the topical evidence about the dysfunction of the pituitary-bone axis that leads to osteoporotic bone loss. We will explore the context of FSH and TSH hormones arguing their direct or indirect role in bone loss. In addition, we will focus on the knowledge that both FSH and TSH have influence on...

  19. Off-Axis Astigmatic Gaussian Beam Combination Beyond the Paraxial Approximation

    Institute of Scientific and Technical Information of China (English)

    GAO Zeng-Hui; L(U) Bai-Da

    2007-01-01

    Taking the off-axis astigmatic Gaussian beam combination as an example, the beam-combination concept is extended to the nonparaxial regime. The closed-form propagation expressions for coherent and incoherent combinations of nonparaxial off-axis astigmatic Gaussian beams with rectangular geometry are derived and illustrated with numerical examples. It is shown that the intensity distributions of the resulting beam depend on the combination scheme and beam parameters in general, and in the paraxial approximation (i.e., for the small f-parameter)our results reduce to the paraxial ones.

  20. New one-axis one-sensor magnetic attitude control theoretical and in-flight performance

    Science.gov (United States)

    Ovchinnikov, M. Yu.; Roldugin, D. S.; Tkachev, S. S.; Karpenko, S. O.

    2014-12-01

    New one-axis magnetic attitude control is proposed. Only one attitude sensor providing any inertial direction measurements is necessary, magnetometer is not used. The control may be used as a backup capability in case main actuators or some attitude sensors fail. Sun pointing is achievable using only three-axis Sun sensor, so the control may be used to lower the power consumption during battery charging. Asymptotic stability of different equilibria depending on the satellite inertia tensor is summarized. In-flight results from "Chibis-M" microsatellite are provided proving general control performance.

  1. Platform for Attitude Control Experiment (PACE): An Experimental Three-Axis Stabilized CubeSat

    OpenAIRE

    Tu, Jung-Kuo; Wu, Shi-Hua; Chu, Chen-Chi

    2004-01-01

    Owing to their low cost, fast development time, and multi-discipline educational purpose, CubeSats have been widely advocated by universities in recent years. However, few have employed three-axis stabilization schemes due mainly to the limitation of power and mass. The PACE, Platform for Attitude Control Experiment for short, is a three-axis stabilizing CubeSat developed at the National Cheng Kung University. It is a 20x10x10 cm3 double cube satellite weight less than 2-kg. A miniature momen...

  2. Bubble and skyrmion crystals in frustrated magnets with easy-axis anisotropy

    Science.gov (United States)

    Hayami, Satoru; Lin, Shi-Zeng; Batista, Cristian D.

    2016-05-01

    We clarify the conditions for the emergence of multiple-Q structures out of lattice and easy-axis spin anisotropy in frustrated magnets. By considering magnets whose exchange interaction has multiple global minima in momentum space, we find that both types of anisotropy stabilize triple-Q orderings. Moderate anisotropy leads to a magnetic-field-induced skyrmion crystal, which evolves into a bubble crystal for increasing spatial and spin anisotropy. The bubble crystal exhibits a quasicontinuous (devil's staircase) temperature-dependent ordering wave vector, characteristic of the competition between frustrated exchange and strong easy-axis anisotropy.

  3. Optical Design for the Off-axis Reflective Optics with Wide Field

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Reflective optics with wide field of view has been applied more and more widely in EUVL or space optics, and also plays an important role in promoting scientific and technological research. Among the reflective optics, the off-axis reflective optics is the most hopeful solution to the ever-highest demands of these applications. This paper gives the requirements of both the above mentioned applications and the similarities and differences between these two kinds of optical systems. Finally, a design example of off-axis reflective optics with wide field of view is presented and described.

  4. Orbital Angular Momentum in Noncollinear Second Harmonic Generation by off-axis vortex beams

    CERN Document Server

    Bovino, Fabio Antonio; Giardina, Maurizio; Sibilia, Concita

    2011-01-01

    We experimentally study the behavior of orbital angular momentum (OAM) of light in a noncollinear second harmonic generation (SHG) process. The experiment is performed by using a type I BBO crystal under phase matching conditions with femtosecond pumping fields at 830 nm. Two specular off-axis vortex beams carrying fractional orbital angular momentum at the fundamental frequency (FF) are used. We analyze the behavior of the OAM of the SH signal when the optical vortex of each input field at the FF is displaced from the beam's axis. We obtain different spatial configurations of the SH field, always carrying the same zero angular momentum.

  5. Innovative Design of Vertical Axis Wind Turbine:a poster presented at DAMAS 2013 conference

    OpenAIRE

    Chougule, Prasad

    2013-01-01

    The wind turbines can be classified as: i) Horizontal axis windturbines (HAWT), and ii) Vertical axis wind turbines (VAWT). TheHAWT is fully developed and the size is growing higher. Whereas,the VAWT is not developed because of the less efficiency andvibration issues of big structure. However, it is well known that theVAWT is advantages over a HAWT in terms of a cost and thesimplicity (Paraschivoiu 2002). In this PhD project a simple bladedesign is incorporated by using the two-element airofo...

  6. Atomic resolution electrostatic potential mapping of graphene sheets by off-axis electron holography

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, David, E-mail: david.cooper@cea.fr [University Grenoble Alpes, F-38000 Grenoble (France); CEA, LETI, MINATEC Campus, F-38054, Grenoble (France); Pan, Cheng-Ta; Haigh, Sarah [School of Materials, The University of Manchester, Manchester M13 9PL (United Kingdom)

    2014-06-21

    Off-axis electron holography has been performed at atomic resolution with the microscope operated at 80 kV to provide electrostatic potential maps from single, double, and triple layer graphene. These electron holograms have been reconstructed in order to obtain information about atomically resolved and mean inner potentials. We propose that off-axis electron holography can now be used to measure the electrical properties in a range of two-dimensional semiconductor materials and three dimensional devices comprising stacked layers of films to provide important information about their electrical properties.

  7. A Singular Limit Problem for Rotating Capillary Fluids with Variable Rotation Axis

    Science.gov (United States)

    Fanelli, Francesco

    2016-04-01

    In the present paper we study a singular perturbation problem for a Navier-Stokes-Korteweg model with Coriolis force. Namely, we perform the incompressible and fast rotation asymptotics simultaneously, while we keep the capillarity coefficient constant in order to capture surface tension effects in the limit. We consider here the case of variable rotation axis: we prove the convergence to a linear parabolic-type equation with variable coefficients. The proof of the result relies on compensated compactness arguments. Besides, we look for minimal regularity assumptions on the variations of the axis.

  8. Micromagnetic simulation on effect of oersted field and hard axis field in spin transfer torque switching

    International Nuclear Information System (INIS)

    The effects of the current-induced Oersted field and of a hard axis applied field on spin transfer torque (STT) switching have been investigated by performing LLG micromagnetic simulations including a STT term and Gaussian thermal fluctuations. In parallel to anti-parallel switching at large currents, the C-like micromagnetic configuration induced by the Oersted field plays an important role in STT switching. In anti-parallel to parallel switching at large currents, the Oersted field induces a complicated micromagnetic configuration with several vortices. In both cases, the magnetization deviates considerably from macrospin behaviour. However, a macrospin-like behaviour is restored when a hard axis field is present

  9. Precision Attitude Determination System (PADS) system design and analysis: Single-axis gimbal star tracker

    Science.gov (United States)

    1974-01-01

    The feasibility is evaluated of an evolutionary development for use of a single-axis gimbal star tracker from prior two-axis gimbal star tracker based system applications. Detailed evaluation of the star tracker gimbal encoder is considered. A brief system description is given including the aspects of tracker evolution and encoder evaluation. System analysis includes evaluation of star availability and mounting constraints for the geosynchronous orbit application, and a covariance simulation analysis to evaluate performance potential. Star availability and covariance analysis digital computer programs are included.

  10. Response to centrifugal and axi-vane blowers to large pressure transients

    International Nuclear Information System (INIS)

    The effect of large pressure pulses on the operation of centrifugal and axi-vane blowers of the types found in ventilation systems used in the mining and nuclear industries was investigated using the Los Alamos National Laboratory/New Mexico State University fluid dynamics test facility. Three blowers were tested for both quasi-steady and transient pressures: a 24-in. and a 12-in. centrifugal blower and a 33-in. axi-vane blower were subjected to pressure pulses at their exhaust and inlet, which caused backflow and outrunning flow, respectively. Performance curves were obtained for the first, second, and fourth quadrants

  11. A Simplified Model for Fatigue Load Calculations of Small Wind- Turbines with Vertical Axis of Rotation

    OpenAIRE

    Schaffarczyk, A. P.; Kemena, Tronje

    2008-01-01

    Wind Turbines with a vertical axis of rotation (VAWT) recently regained new interest. In this paper we summarize results from [2] in which our new aerodynamic model [1] was applied to an existing 50 kW machine. The presentation is organized as follows: First we present our simplified model which was formulated in closest analogy along the rules from IEC 61400-2 used for horizontal axis wind-turbines including some rigid-body extensions. Second we shortly discuss the only to us known aeroelast...

  12. 3Dwheel: 3-axis low-noise, high-bandwidth attitude actuation from a single momentum wheel using magnetic bearings.

    OpenAIRE

    Seddon, Jon; Pechev, Alexandre

    2009-01-01

    This paper proposes a new concept for attitude actuation for small satellites that uses active magnetic bearings to support and tilt a spinning rotor to provide 3-axis attitude control of the satellite using a single actuator. A controlled 3D motion in the spinning rotor provides a conventional torque output about the momentum axis and a gyroscopic torque output about any direction in the plane normal to the spinning axis. Therefore, a single tilting momentum-wheel can generate torque along t...

  13. Using a double-frequency RF system to facilitate on-axis beam accumulation in a storage ring

    CERN Document Server

    Jiang, B C; Tian, S Q; Zhang, M Z; Zhang, Q L

    2016-01-01

    An on-axis injection scheme using a double-frequency RF system in a storage ring with small dynamic aperture is proposed. By altering RF voltages, empty RF buckets can be created which will be used for on-axis injection. After bunches are injected, a reverse RF voltage altering process is performed and the injected bunches can be longitudinally dumped to the main RF buckets. The scheme allows reaping the advantages of the on-axis injection while still performing accumulation.

  14. Small vertical axis-wind turbines. Also adaptable for owner-occupied homes; Kleine vertikalachsige Windturbinen. Auch fuer Eigenheime geeignet

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Sigmund

    2013-02-01

    So-called vertical axis-wind turbines are becoming more and more accepted because these wind turbines operate independently from the wind direction, have a low noise level, require a lower mast height in comparison to horizontal axis-wind turbines and are perceived by birds as a complete object. Vertical axis-wind turbines can be utilized in built-up areas. The author of the contribution under consideration considers the differences of the various technologies and levels of development of vertical axis wind turbines.

  15. Acute iron overload leads to hypothalamic-pituitary-gonadal axis abnormalities in female rats.

    Science.gov (United States)

    Rossi, Emilly M; Marques, Vinicius B; Nunes, Dieli de O; Carneiro, Maria T W D; Podratz, Priscila L; Merlo, Eduardo; dos Santos, Leonardo; Graceli, Jones B

    2016-01-01

    Iron plays a critical role in a mammal's physiological processes. However, iron tissue deposits have been shown to act as endocrine disrupters. Studies that evaluate the effect of acute iron overload on hypothalamic-pituitary-gonadal (HPG) axis health are particularly sparse. This study demonstrates that acute iron overload leads to HPG axis abnormalities, including iron accumulation and impairment in reproductive tract morphology. Female rats were treated with iron-dextran (Fe rats) to assess their HPG morphophysiology. The increasing serum iron levels due to iron-dextran treatment were positively correlated with higher iron accumulation in the HPG axis and uterus of Fe rats than in control rats. An increase in the production of superoxide anions was observed in the pituitary, uterus and ovary of Fe rats. Morphophysiological reproductive tract abnormalities, such as abnormal ovarian follicular development and the reduction of serum estrogen levels, were observed in Fe rats. In addition, a significant negative correlation was obtained between ovary superoxide anion and serum estrogen levels. Together, these data provide in vivo evidence that acute iron overload is toxic for the HPG axis, a finding that may be associated with the subsequent development of the risk of reproductive dysfunction. PMID:26536400

  16. Impact of Sleep and Its Disturbances on Hypothalamo-Pituitary-Adrenal Axis Activity

    Directory of Open Access Journals (Sweden)

    Eve Van Cauter

    2010-01-01

    Full Text Available The daily rhythm of cortisol secretion is relatively stable and primarily under the influence of the circadian clock. Nevertheless, several other factors affect hypothalamo-pituitary-adrenal (HPA axis activity. Sleep has modest but clearly detectable modulatory effects on HPA axis activity. Sleep onset exerts an inhibitory effect on cortisol secretion while awakenings and sleep offset are accompanied by cortisol stimulation. During waking, an association between cortisol secretory bursts and indices of central arousal has also been detected. Abrupt shifts of the sleep period induce a profound disruption in the daily cortisol rhythm, while sleep deprivation and/or reduced sleep quality seem to result in a modest but functionally important activation of the axis. HPA hyperactivity is clearly associated with metabolic, cognitive and psychiatric disorders and could be involved in the well-documented associations between sleep disturbances and the risk of obesity, diabetes and cognitive dysfunction. Several clinical syndromes, such as insomnia, depression, Cushing's syndrome, sleep disordered breathing (SDB display HPA hyperactivity, disturbed sleep, psychiatric and metabolic impairments. Further research to delineate the functional links between sleep and HPA axis activity is needed to fully understand the pathophysiology of these syndromes and to develop adequate strategies of prevention and treatment.

  17. Prenatal undernutrition and postnatal overnutrition alter thyroid hormone axis function in sheep

    DEFF Research Database (Denmark)

    Johnsen, Lærke; Kongsted, Anna Hauntoft; Nielsen, Mette Olaf

    2013-01-01

    adipose tissues. EL-ON increased TH levels in adolescent lambs, but this was reversed after diet correction, and not evident in adulthood. We conclude that LG-UN programmed TH-axis function at the secretory level and differentially in target tissues, which was increasingly manifested with age...

  18. A quantitative adverse outcome pathway model for thyroid axis disruption in Xenopus laevis tadpoles

    Science.gov (United States)

    The development of Xenopus laevis tadpoles is tightly controlled by the thyroid hormones tetraiodothyronine (T4) and triiodothyronine (T3). Toxicity testing efforts have shown that several compounds interfere with development in X. laevis tadpoles by disrupting the thyroid axis a...

  19. CT analysis of the axis for transarticular screw fixation of rheumatoid atlantoaxial instability

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Sung Soo; Lee, Chong Suh; Kang, Chang Seok [Sungkyunkwan University School of Medicine, Department of Orthopedic Surgery, Samsung Medical Center, Seoul (Korea); Chung, Hye Won [Sungkyunkwan University School of Medicine, Department of Radiology, Samsung Medical Center, Seoul (Korea)

    2006-09-15

    To investigate the morphological characteristics of the axis of rheumatoid arthritis (RA) patients with atlantoaxial instability and to determine, by means of sagittal reconstructed computed tomography (CT), the suitability for atlantoaxial transarticular screw fixation. Twenty-seven patients, who had undergone reconstructed cervical spine CT scanning preoperatively and posterior atlantoaxial arthrodesis for atlantoaxial instability, were identified from a database for inclusion in this study. The isthmus height and internal height of the lateral mass of the axis were measured using digital imaging software. The mean isthmus height and internal height of the lateral mass of the axis in RA patients (n=14) were significantly lower than in non-RA patients (n=13) (P<0.01). A high-riding vertebral artery (VA) was present in 54% (15 joints, 9 patients) of the 28 atlantoaxial joints in the RA group and in 12% (3 joints, 2 patients) of the 26 atlantoaxial joints in the non-RA group (P<0.01). In RA patients, the axis showed more extensive thinning of the isthmus and lateral mass than in non-RA patients. A precise preoperative evaluation of screw trajectory using reconstruction CT imaging may be useful in atlantoaxial transarticular fixation, particularly for RA patients with atlantoaxial instability. (orig.)

  20. Hybrid version of the tilted axis cranking model and its application to 128Ba

    International Nuclear Information System (INIS)

    A hybrid version the deformed nuclear potential is suggested, which combines a spherical Woods-Saxon potential with a deformed Nilsson potential. It removes the problems of the conventional Nilsson potential in the mass 130 region. Based on the hybrid potential, tilted axis cranking calculations are carried out for the magnetic dipole band in 128Ba. (c) 2000 The American Physical Society