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Sample records for level npc inverter

  1. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    NASA Astrophysics Data System (ADS)

    Gheraia, H.; Berkouk, E. M.; Manesse, G.

    2001-08-01

    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction.

  2. Analysis and carrier-based modulation of Z-source NPC inverters

    NASA Astrophysics Data System (ADS)

    Dehghan, Seyed Mohammad; Mohamadian, Mustafa; Gharekhani, Reza

    2012-08-01

    Multi-level neutral-point-clamped (NPC) inverters are widely used in high and medium voltage applications. However, these inverters are only buck-type converters. Recently z-source NPC inverters have been proposed as the buck-boost three-level inverter. New inverters use a z-source network as the input stage. This article analyses the features and limitations of two main topologies of z-source NPC inverters (dual z-source network NPC inverter and single z-source network NPC inverter). The low-frequency ripple of the inductor current and the capacitor voltage of the z-source networks in the z-source NPC inverters are surveyed. This article also proposes two novel PWM methods for the z-source NPC inverters, which can be easily implemented experimentally. In the proposed methods, generated switching signals for the conventional NPC inverter are modified for the z-source NPC inverter using a simple logic circuit considering the boost factors and the power sharing ratio. The performance of the proposed simple PWM methods is verified by simulation and experimental results.

  3. Fault-tolerant three-level inverter

    DOEpatents

    Edwards, John; Xu, Longya; Bhargava, Brij B.

    2006-12-05

    A method for driving a neutral point clamped three-level inverter is provided. In one exemplary embodiment, DC current is received at a neutral point-clamped three-level inverter. The inverter has a plurality of nodes including first, second and third output nodes. The inverter also has a plurality of switches. Faults are checked for in the inverter and predetermined switches are automatically activated responsive to a detected fault such that three-phase electrical power is provided at the output nodes.

  4. Genetic demonstration of intestinal NPC1L1 as a major determinant of hepatic cholesterol and blood atherogenic lipoprotein levels

    PubMed Central

    Xie, Ping; Zhu, Hongling; Jia, Lin; Ma, Yinyan; Tang, Weiqing; Wang, Youlin; Xue, Bingzhong; Shi, Hang; Yu, Liqing

    2014-01-01

    Objective The correlation between intestinal cholesterol absorption values and plasma low-density lipoprotein-cholesterol (LDL-C) levels remains controversial. Niemann-Pick-C1-Like 1 (NPC1L1) is essential for intestinal cholesterol absorption, and is the target of ezetimibe, a cholesterol absorption inhibitor. However, studies with NPC1L1 knockout mice or ezetimibe cannot definitively clarify this correlation because NPC1L1 expression is not restricted to intestine in humans and mice. In this study we sought to genetically address this issue. Methods and results We developed a mouse model that lacks endogenous (NPC1L1) and LDL receptor (LDLR) (DKO), but transgenically expresses human NPC1L1 in gastrointestinal tract only (DKO/L1IntOnly mice). Our novel model eliminated potential effects of non-intestinal NPC1L1 on cholesterol homeostasis. We found that human NPC1L1 was localized at the intestinal brush border membrane of DKO/L1IntOnly mice. Cholesterol feeding induced formation of NPC1L1-positive vesicles beneath this membrane in an ezetimibe-sensitive manner. Compared to DKO mice, DKO/L1IntOnly mice showed significant increases in cholesterol absorption and blood/hepatic/biliary cholesterol. Increased blood cholesterol was restricted to very low-density lipoprotein (VLDL) and LDL fractions, which was associated with increased secretion and plasma levels of apolipoproteins B100 and B48. Additionally, DKO/L1IntOnly mice displayed decreased fecal cholesterol excretion and hepatic/intestinal expression of cholesterologenic genes. Ezetimibe treatment virtually reversed all of the transgene-related phenotypes in DKO/L1IntOnly mice. Conclusion Our findings from DKO/L1IntOnly mice clearly demonstrate that NPC1L1-mediated cholesterol absorption is a major determinant of blood levels of apolipoprotein B-containing atherogenic lipoproteins, at least in mice. PMID:25463095

  5. Reduced VLDL clearance in Apoe(-/-)Npc1(-/-) mice is associated with increased Pcsk9 and Idol expression and decreased hepatic LDL-receptor levels.

    PubMed

    Ishibashi, Minako; Masson, David; Westerterp, Marit; Wang, Nan; Sayers, Scott; Li, Rong; Welch, Carrie L; Tall, Alan R

    2010-09-01

    Niemann-Pick type C1 (NPC1) promotes the transport of LDL receptor (LDL-R)-derived cholesterol from late endosomes/lysosomes to other cellular compartments. NPC1-deficient cells showed impaired regulation of liver_X receptor (LXR) and sterol regulatory element-binding protein (SREBP) target genes. We observed that Apoe(-/-)Npc1(-/-) mice displayed a marked increase in total plasma cholesterol mainly due to increased VLDL, reflecting decreased clearance. Although nuclear SREBP-2 and Ldlr mRNA levels were increased in Apoe(-/-)Npc1(-/-) liver, LDL-R protein levels were decreased in association with marked induction of proprotein convertase subtilisin/kexin type 9 (Pcsk9) and inducible degrader of the LDL-R (Idol), both known to promote proteolytic degradation of LDL-R. While Pcsk9 is known to be an SREBP-2 target, marked upregulation of IDOL in Apoe(-/-)Npc1(-/-) liver was unexpected. However, several other LXR target genes also increased in Apoe(-/-)Npc1(-/-) liver, suggesting increased synthesis of endogenous LXR ligands secondary to activation of sterol biosynthesis. In conclusion, we demonstrate that NPC1 deficiency has a major impact on VLDL metabolism in Apoe(-/-) mice through modulation of hepatic LDL-R protein levels. In contrast to modest induction of hepatic IDOL with synthetic LXR ligands, a striking upregulation of IDOL in Apoe(-/-)Npc1(-/-) mice could indicate a role of endogenous LXR ligands in regulation of hepatic IDOL. PMID:20562239

  6. Identification of lysosomal Npc1-binding proteins: Cathepsin D activity is regulated by NPC1.

    PubMed

    Macías-Vidal, Judit; Guerrero-Hernández, Martina; Estanyol, Josep Maria; Aguado, Carmen; Knecht, Erwin; Coll, Maria Josep; Bachs, Oriol

    2016-01-01

    Niemann-Pick type C (NPC) disease is an inherited lysosomal storage disorder, characterized by severe neurodegeneration. It is mostly produced by mutations in the NPC1 gene, encoding for a protein of the late endosomes/lysosomes membrane, involved in cholesterol metabolism. However, the specific role of this protein in NPC disease still remains unknown. We aimed to identify Npc1-binding proteins in order to define new putative NPC1 lysosomal functions. By affinity chromatography using an Npc1 peptide (amino acids 1032-1066 of loop I), as bait, we fished 31 lysosomal proteins subsequently identified by LC-MS/MS. Most of them were involved in proteolysis and lipid catabolism and included the protease cathepsin D. Cathepsin D and NPC1 interaction was validated by immunoprecipitation and the functional relevance of this interaction was studied. We found that fibroblasts from NPC patients with low levels of NPC1 protein have high amounts of procathepsin D but reduced quantities of the mature protein, thus showing a diminished cathepsin D activity. The increase of NPC1 protein levels in NPC cells by treatment with the proteasome inhibitor bortezomib, induced an elevation of cathepsin D activity. All these results suggest a new lysosomal function of NPC1 as a regulator of cathepsin D processing and activity. PMID:26507101

  7. Prediction of 2-level PWM inverter efficiency using MATLAB/Simulink

    NASA Astrophysics Data System (ADS)

    Kim, Yoon-Ho; Kim, Seong-Je

    2015-10-01

    This article proposes a direct approach for the prediction of inverter efficiency using MATLAB/Simulink, instead of an indirect loss calculation approach based on analytical models. In analytical approach, efficiency is obtained by calculating individual losses separately, such as switching losses, conduction losses and harmonic losses using analytical models. However, this approach requires accurate analytical models and complicated calculations, due to the variation in the switching frequency, switching transient and modulation techniques. In the proposed approach, the actual waveform of the inverter system is directly generated using MATLAB/Simulink. The instantaneous voltage and current waveform including switching transients are generated. Thus, the proposed approach is very simple and convenient for efficiency prediction. The proposed approach also works for any system parameters or control methods, such as various pulse-width modulation (PWM) techniques, different switching frequencies, switching devices and load types. The proposed approach can be adopted for the efficiency prediction of any switching strategies and any types of inverters such as neutral-point-clamped (NPC) inverters, H bridge inverters and H5 topology, since the topologies are modelled as circuits in the MATLAB/Simulink program and no analytical model is required for the proposed approach. Furthermore, the proposed approach can provide operation techniques and conditions such as PWM techniques and switching frequency that offer high efficiency. In this article, inverter performance is evaluated for various PWM techniques and switching frequencies. The PWM technique and switching frequency that offer high efficiency is obtained. Finally, the proposed approach is verified by experimental results.

  8. Advanced Inverter Functions to Support High Levels of Distributed Solar: Policy and Regulatory Considerations (Brochure)

    SciTech Connect

    Not Available

    2014-11-01

    This paper explains how advanced inverter functions (sometimes called 'smart inverters') contribute to the integration of high levels of solar PV generation onto the electrical grid and covers the contributions of advanced functions to maintaining grid stability. Policy and regulatory considerations associated with the deployment of advanced inverter functions are also introduced.

  9. Pulmonary Abnormalities in Animal Models Due to Niemann-Pick Type C1 (NPC1) or C2 (NPC2) Disease

    PubMed Central

    Roszell, Blair R.; Tao, Jian-Qin; Yu, Kevin J.; Gao, Ling; Huang, Shaohui; Ning, Yue; Feinstein, Sheldon I.; Vite, Charles H.; Bates, Sandra R.

    2013-01-01

    Niemann-Pick C (NPC) disease is due to loss of NPC1 or NPC2 protein function that is required for unesterified cholesterol transport from the endosomal/lysosomal compartment. Though lung involvement is a recognized characteristic of Niemann-Pick type C disease, the pathological features are not well understood. We investigated components of the surfactant system in both NPC1 mutant mice and felines and in NPC2 mutant mice near the end of their expected life span. Histological analysis of the NPC mutant mice demonstrated thickened septae and foamy macrophages/leukocytes. At the level of electron microscopy, NPC1-mutant type II cells had uncharacteristically larger lamellar bodies (LB, mean area 2-fold larger), while NPC2-mutant cells had predominantly smaller lamellar bodies (mean area 50% of normal) than wild type. Bronchoalveolar lavage from NPC1 and NPC2 mutant mice had an approx. 4-fold and 2.5-fold enrichment in phospholipid, respectively, and an approx. 9-fold and 35-fold enrichment in cholesterol, consistent with alveolar lipidosis. Phospholipid and cholesterol also were elevated in type II cell LBs and lung tissue while phospholipid degradation was reduced. Enrichment of surfactant protein-A in the lung and surfactant of the mutant mice was found. Immunocytochemical results showed that cholesterol accumulated in the LBs of the type II cells isolated from the affected mice. Alveolar macrophages from the NPC1 and NPC2 mutant mice were enlarged compared to those from wild type mice and were enriched in phospholipid and cholesterol. Pulmonary features of NPC1 mutant felines reflected the disease described in NPC1 mutant mice. Thus, with the exception of lamellar body size, the lung phenotype seen in the NPC1 and NPC2 mutant mice were similar. The lack of NPC1 and NPC2 proteins resulted in a disruption of the type II cell surfactant system contributing to pulmonary abnormalities. PMID:23843985

  10. Photodynamic effect of curcumin on NPC/CNE2 cells.

    PubMed

    Koon, H; Leung, Albert W N; Yue, Kevin K M; Mak, Naiki K

    2006-01-01

    Nasopharyngeal carcinoma (NPC) is highly prevalent in Southern China. Radiotherapy is the primary treatment of NPC, but the rate of tumor recurrence is significant. Photodynamic therapy (PDT) and the use of natural compounds become one of the new approaches in the investigation of NPC treatment. PDT is an alternate method of cancer treatment while curcumin (CUR) is a compound derived from the traditional Chinese medicinal (TCM) herbs. The purpose of the study focuses on the photodynamic effect of CUR on one of the NPC cell lines, NPC/CNE2. Cytotoxicity and photocytotoxicity of CUR were evaluated by 3-(4,5-dimthyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. Uptake kinetics of CUR in NPC/CNE2 was examined by flow cytometry. The mode of cell death induced by CUR was studied by fluorescence microscopy. Summarizing the results, CUR showed dark cytotoxicity as well as photocytotoxic effects on NPC/CNE2 cells. LC50 of CUR in the dark was about 16 microM. The cytotoxicity of CUR was enhanced by the irradiation of visible light and blue filtered light (maximum transmittance at 300 approximately 400 nm) with light doses of 300 kJ/m2 and 60 kJ/m2 respectively. NPC/CNE2 was found to rapidly take up CUR in the first hour of incubation, and the uptake kinetics steadily increased to a plateau level after 20 hr of incubation. Cell shrinkage and membrane bledding appeared under the observation of fluorescence microscopy. Such evidences proved that CUR might induce apoptosis on NPC/CNE2 cells. The preliminary study confirmed that CUR demonstrated dark cytotoxicity and photocytotoxicty to NPC/CNE2. The mode of action is likely to be induced by apoptotic pathway. CUR may be developed as a potential photosensitizer as well as a chemotherapeutic agent in clinical application. PMID:16566718

  11. The metamorphosis in the emission angular profile from an inverted two-level atoms system

    NASA Astrophysics Data System (ADS)

    Friedberg, Richard; Manassah, Jamal T.

    2009-08-01

    A rich variety of angular distributions in the cooperative emission from a sphere of inverted N two-level atoms are shown to result from the eigenstructure of the complex kernel of scalar photon theory exp( ik0R)/( ik0R). This angular distribution is sensitive both to the size of the sphere and to the instant of observation of the emission.

  12. Fundamental Frequency Switching Control of Seven-Level Hybrid Cascaded H-bridge Multilevel Inverter

    SciTech Connect

    Du, Zhong; Chiasson, John N; Ozpineci, Burak; Tolbert, Leon M

    2009-01-01

    This paper presents a cascaded H-bridge multilevel inverter that can be implemented using only a single dc power source and capacitors. Standard cascaded multilevel inverters require n dc sources for 2n + 1 levels. Without requiring transformers, the scheme proposed here allows the use of a single dc power source (e.g., a battery or a fuel cell stack) with the remaining n-1 dc sources being capacitors, which is referred to as hybrid cascaded H-bridge multilevel inverter (HCMLI) in this paper. It is shown that the inverter can simultaneously maintain the dc voltage level of the capacitors and choose a fundamental frequency switching pattern to produce a nearly sinusoidal output. HCMLI using only a single dc source for each phase is promising for high-power motor drive applications as it significantly decreases the number of required dc power supplies, provides high-quality output power due to its high number of output levels, and results in high conversion efficiency and low thermal stress as it uses a fundamental frequency switching scheme. This paper mainly discusses control of seven-level HCMLI with fundamental frequency switching control and how its modulation index range can be extended using triplen harmonic compensation.

  13. High performance control of a three-level IGBT inverter fed AC drive

    SciTech Connect

    Zhang, J.

    1995-12-31

    Three-level PWM inverters have been increasingly employed in industry and traction applications where high power and efficiency energy conversions are required. This paper presents a high performance control of a cage induction motor drive fed by a 100 Hp three-level IGBT inverter operating at a low switching frequency. A practical math model of the drive control system is established to aid in the control design to improve the system stability, dynamic performance and robustness over a wide speed range. The modeling and the simulation in Matlab/Simulink facilitate the self-tuning of the regulators in the multi-loop systems. The field oriented control and three-level space-vector modulation together with the drive protection and diagnostics are implemented in software based on a DSP TMS320C31. Experimental results based on the IGBT inverter prototype are given to verify the design and performance. Test results in motor common-mode voltage reduction and inverter neutral-point potential control re also briefly presented.

  14. A new balancing three level three dimensional space vector modulation strategy for three level neutral point clamped four leg inverter based shunt active power filter controlling by nonlinear back stepping controllers.

    PubMed

    Chebabhi, Ali; Fellah, Mohammed Karim; Kessal, Abdelhalim; Benkhoris, Mohamed F

    2016-07-01

    In this paper is proposed a new balancing three-level three dimensional space vector modulation (B3L-3DSVM) strategy which uses a redundant voltage vectors to realize precise control and high-performance for a three phase three-level four-leg neutral point clamped (NPC) inverter based Shunt Active Power Filter (SAPF) for eliminate the source currents harmonics, reduce the magnitude of neutral wire current (eliminate the zero-sequence current produced by single-phase nonlinear loads), and to compensate the reactive power in the three-phase four-wire electrical networks. This strategy is proposed in order to gate switching pulses generation, dc bus voltage capacitors balancing (conserve equal voltage of the two dc bus capacitors), and to switching frequency reduced and fixed of inverter switches in same times. A Nonlinear Back Stepping Controllers (NBSC) are used for regulated the dc bus voltage capacitors and the SAPF injected currents to robustness, stabilizing the system and to improve the response and to eliminate the overshoot and undershoot of traditional PI (Proportional-Integral). Conventional three-level three dimensional space vector modulation (C3L-3DSVM) and B3L-3DSVM are calculated and compared in terms of error between the two dc bus voltage capacitors, SAPF output voltages and THDv, THDi of source currents, magnitude of source neutral wire current, and the reactive power compensation under unbalanced single phase nonlinear loads. The success, robustness, and the effectiveness of the proposed control strategies are demonstrated through simulation using Sim Power Systems and S-Function of MATLAB/SIMULINK. PMID:27018144

  15. A Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source

    SciTech Connect

    Chiasson, J. N.

    2006-10-01

    A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

  16. Advanced Inverter Technology for High Penetration Levels of PV Generation in Distribution Systems

    SciTech Connect

    Schauder, C.

    2014-03-01

    This subcontract report was completed under the auspices of the NREL/SCE High-Penetration Photovoltaic (PV) Integration Project, which is co-funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and the California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) program funded by the California Public Utility Commission (CPUC) and managed by Itron. This project is focused on modeling, quantifying, and mitigating the impacts of large utility-scale PV systems (generally 1-5 MW in size) that are interconnected to the distribution system. This report discusses the concerns utilities have when interconnecting large PV systems that interconnect using PV inverters (a specific application of frequency converters). Additionally, a number of capabilities of PV inverters are described that could be implemented to mitigate the distribution system-level impacts of high-penetration PV integration. Finally, the main issues that need to be addressed to ease the interconnection of large PV systems to the distribution system are presented.

  17. A Five-Level Three-Phase Cascade Multilevel Inverter Using a Single DC Source for a PM Synchronous Motor Drive

    SciTech Connect

    Ozpineci, Burak; Chiasson, John N; Tolbert, Leon M

    2007-01-01

    The interest here is in using a single DC power source to construct a 3-phase 5-level cascade multilevel inverter to be used as a drive for a PM traction motor. The 5-level inverter consists of a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg, which use a capacitor as a DC source. It is shown that one can simultaneously maintain the regulation of the capacitor voltage while achieving an output voltage waveform which is 25% higher than that obtained using a standard 3-leg inverter by itself.

  18. Inverted barometer contributions to recent sea level changes along the northeast coast of North America

    NASA Astrophysics Data System (ADS)

    Piecuch, Christopher G.; Ponte, Rui M.

    2015-07-01

    Regional sea level (SL) changes reflect dynamic and isostatic ocean effects. Recent works have interpreted accelerated and extreme SL changes along the northeast coast of North America primarily in terms of dynamic changes; however, dedicated study of isostatic changes related to surface atmospheric pressure loading—the inverted barometer (IB) effect—has been lacking. This investigation uses five different atmospheric pressure products to analyze the influence of the IB effect on annual mean SL from tide gauge records. The IB effect explains ˜25% of interannual SL variance and accounts for ˜50% of the magnitude of a recent extreme event of SL rise along Atlantic Canada and New England. Estimated IB effects also amount to ˜10-30% of recent multidecadal SL accelerations over the Mid-Atlantic Bight and Southern New England. These findings reiterate the need for careful estimation and removal of isostatic effects for studies of dynamic SL.

  19. A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources

    NASA Astrophysics Data System (ADS)

    Sotoodeh, Pedram

    This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10-20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

  20. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles

    PubMed Central

    Ndungo, Esther; Herbert, Andrew S.; Raaben, Matthijs; Obernosterer, Gregor; Biswas, Rohan; Miller, Emily Happy; Wirchnianski, Ariel S.; Carette, Jan E.; Brummelkamp, Thijn R.; Whelan, Sean P.

    2016-01-01

    ABSTRACT Filoviruses are the causative agents of an increasing number of disease outbreaks in human populations, including the current unprecedented Ebola virus disease (EVD) outbreak in western Africa. One obstacle to controlling these epidemics is our poor understanding of the host range of filoviruses and their natural reservoirs. Here, we investigated the role of the intracellular filovirus receptor, Niemann-Pick C1 (NPC1) as a molecular determinant of Ebola virus (EBOV) host range at the cellular level. Whereas human cells can be infected by EBOV, a cell line derived from a Russell’s viper (Daboia russellii) (VH-2) is resistant to infection in an NPC1-dependent manner. We found that VH-2 cells are resistant to EBOV infection because the Russell’s viper NPC1 ortholog bound poorly to the EBOV spike glycoprotein (GP). Analysis of panels of viper-human NPC1 chimeras and point mutants allowed us to identify a single amino acid residue in NPC1, at position 503, that bidirectionally influenced both its binding to EBOV GP and its viral receptor activity in cells. Significantly, this single residue change perturbed neither NPC1’s endosomal localization nor its housekeeping role in cellular cholesterol trafficking. Together with other recent work, these findings identify sequences in NPC1 that are important for viral receptor activity by virtue of their direct interaction with EBOV GP and suggest that they may influence filovirus host range in nature. Broader surveys of NPC1 orthologs from vertebrates may delineate additional sequence polymorphisms in this gene that control susceptibility to filovirus infection. IMPORTANCE Identifying cellular factors that determine susceptibility to infection can help us understand how Ebola virus is transmitted. We asked if the EBOV receptor Niemann-Pick C1 (NPC1) could explain why reptiles are resistant to EBOV infection. We demonstrate that cells derived from the Russell’s viper are not susceptible to infection because EBOV

  1. A Single Residue in Ebola Virus Receptor NPC1 Influences Cellular Host Range in Reptiles.

    PubMed

    Ndungo, Esther; Herbert, Andrew S; Raaben, Matthijs; Obernosterer, Gregor; Biswas, Rohan; Miller, Emily Happy; Wirchnianski, Ariel S; Carette, Jan E; Brummelkamp, Thijn R; Whelan, Sean P; Dye, John M; Chandran, Kartik

    2016-01-01

    Filoviruses are the causative agents of an increasing number of disease outbreaks in human populations, including the current unprecedented Ebola virus disease (EVD) outbreak in western Africa. One obstacle to controlling these epidemics is our poor understanding of the host range of filoviruses and their natural reservoirs. Here, we investigated the role of the intracellular filovirus receptor, Niemann-Pick C1 (NPC1) as a molecular determinant of Ebola virus (EBOV) host range at the cellular level. Whereas human cells can be infected by EBOV, a cell line derived from a Russell's viper (Daboia russellii) (VH-2) is resistant to infection in an NPC1-dependent manner. We found that VH-2 cells are resistant to EBOV infection because the Russell's viper NPC1 ortholog bound poorly to the EBOV spike glycoprotein (GP). Analysis of panels of viper-human NPC1 chimeras and point mutants allowed us to identify a single amino acid residue in NPC1, at position 503, that bidirectionally influenced both its binding to EBOV GP and its viral receptor activity in cells. Significantly, this single residue change perturbed neither NPC1's endosomal localization nor its housekeeping role in cellular cholesterol trafficking. Together with other recent work, these findings identify sequences in NPC1 that are important for viral receptor activity by virtue of their direct interaction with EBOV GP and suggest that they may influence filovirus host range in nature. Broader surveys of NPC1 orthologs from vertebrates may delineate additional sequence polymorphisms in this gene that control susceptibility to filovirus infection. IMPORTANCE Identifying cellular factors that determine susceptibility to infection can help us understand how Ebola virus is transmitted. We asked if the EBOV receptor Niemann-Pick C1 (NPC1) could explain why reptiles are resistant to EBOV infection. We demonstrate that cells derived from the Russell's viper are not susceptible to infection because EBOV cannot bind to

  2. Clues to the mechanism of cholesterol transfer from the structure of NPC1 middle lumenal domain bound to NPC2.

    PubMed

    Li, Xiaochun; Saha, Piyali; Li, Jian; Blobel, Günter; Pfeffer, Suzanne R

    2016-09-01

    Export of LDL-derived cholesterol from lysosomes requires the cooperation of the integral membrane protein Niemann-Pick C1 (NPC1) and a soluble protein, Niemann-Pick C2 (NPC2). Mutations in the genes encoding these proteins lead to Niemann-Pick disease type C (NPC). NPC2 binds to NPC1's second (middle), lumenally oriented domain (MLD) and transfers cholesterol to NPC1's N-terminal domain (NTD). Here, we report the 2.4-Å resolution crystal structure of a complex of human NPC1-MLD and NPC2 bearing bound cholesterol-3-O-sulfate. NPC1-MLD uses two protruding loops to bind NPC2, analogous to its interaction with the primed Ebola virus glycoprotein. Docking of the NPC1-NPC2 complex onto the full-length NPC1 structure reveals a direct cholesterol transfer tunnel between NPC2 and NTD cholesterol binding pockets, supporting the "hydrophobic hand-off" cholesterol transfer model. PMID:27551080

  3. Cholesterol Accumulation Is Associated with Lysosomal Dysfunction and Autophagic Stress in Npc1−/− Mouse Brain

    PubMed Central

    Liao, Guanghong; Yao, Yueqin; Liu, Jihua; Yu, Zhang; Cheung, Simon; Xie, Ang; Liang, Xiaoli; Bi, Xiaoning

    2007-01-01

    Niemann-Pick type C (NPC) disease is an autosomal recessive disorder caused by mutations of NPC1 and NPC2 genes. Progressive neurodegeneration that accompanies NPC is fatal, but the underlying mechanisms are still poorly understood. In the present study, we characterized the association of autophagic-lysosomal dysfunction with cholesterol accumulation in Npc1−/− mice during postnatal development. Brain levels of lysosomal cathepsin D were significantly higher in mutant than in wild-type mice. Increases in cathepsin D occurred first in neurons and later in astrocytes and microglia and were both spatially and temporally associated with intracellular cholesterol accumulation and neurodegeneration. Furthermore, levels of ubiquitinated proteins were higher in endosomal/lysosomal fractions of brains from Npc1−/− mice than from wild-type mice. Immunoblotting results showed that levels of LC3-II were significantly higher in brains of mutant than wild-type mice. Combined LC3 immunofluorescence and filipin staining showed that LC3 accumulated within filipin-labeled cholesterol clusters inside Purkinje cells. Electron microscopic examination revealed the existence of autophagic vacuole-like structures and multivesicles in brains from Npc1−/− mice. These results provide strong evidence that cholesterol accumulation-induced changes in autophagy-lysosome function are closely associated with neurodegeneration in NPC. PMID:17631520

  4. The clathrin adaptor Numb regulates intestinal cholesterol absorption through dynamic interaction with NPC1L1.

    PubMed

    Li, Pei-Shan; Fu, Zhen-Yan; Zhang, Ying-Yu; Zhang, Jin-Hui; Xu, Chen-Qi; Ma, Yi-Tong; Li, Bo-Liang; Song, Bao-Liang

    2014-01-01

    Hypercholesterolemia, typically due to excessive cholesterol uptake, is a major risk factor for cardiovascular disease, which is responsible for ∼50% of all deaths in developed societies. Although it has been shown that intestinal cholesterol absorption is mediated by vesicular endocytosis of the Niemann-Pick C1-like 1 (NPC1L1) protein, the mechanism of sterol-stimulated NPC1L1 internalization is still mysterious. Here, we identified an endocytic peptide signal, YVNXXF (where X stands for any amino acid), in the cytoplasmic C-terminal tail of NPC1L1. Cholesterol binding on the N-terminal domain of NPC1L1 released the YVNXXF-containing region of NPC1L1 from association with the plasma membrane and enabled Numb binding. We also found that Numb, a clathrin adaptor, specifically recognized this motif and recruited clathrin for internalization. Disrupting the NPC1L1-Numb interaction decreased cholesterol uptake. Ablation of Numb in mouse intestine significantly reduced dietary cholesterol absorption and plasma cholesterol level. Together, these data show that Numb is a pivotal protein for intestinal cholesterol absorption and may provide a therapeutic target for hypercholesterolemia. PMID:24336247

  5. Inverting Glacial Isostatic Adjustment with Paleo Sea Level Records using Bayesian Framework and Burgers Rheology

    NASA Astrophysics Data System (ADS)

    Caron, L.; Metivier, L.; Greff-Lefftz, M.; Fleitout, L.; Rouby, H.

    2015-12-01

    Glacial Isostatic Adjustment models most often assume a mantle with a viscoelastic Maxwell rheology and a given ice history model. Here we use a Bayesian Monte Carlo with Markov Chains formalism to invert the global GIA signal simultaneously for the mechanical properties of the mantle and for the volume of the various ice-sheets using as starting ice models two distinct previously published ice histories. Burgers as well as Maxwell rheologies are considered.The fitted data consist of 5720 paleo sea level records from the last 35kyrs, with a world-wide distribution. Our ambition is to present not only the best fitting model, but also the range of possible solutions (within the explored space of parameters) with their respective probability of explaining the data, and thus reveal the trade-off effects and range of uncertainty affecting the parameters. Our a posteriori probality maps exhibit in all cases two distinct peaks: both are characterized by an upper mantle viscosity around 5.1020Pa.s but one of the peaks features a lower mantle viscosity around 3.1021Pa.s while the other indicates lower mantle viscosity of more than 1.1022Pa.s. The global maximum depends upon the starting ice history and the chosen rheology: the first peak (P1) has the highest probability only in the case with a Maxwell rheology and ice history based on ICE-5G, while the second peak (P2) is favored when using ANU-based ice history or Burgers rheology, and is our preferred solution as it is also consistent with long-term geodynamics and gravity gradients anomalies over Laurentide. P2 is associated with larger volumes for the Laurentian and Fennoscandian ice-sheets and as a consequence of total ice volume balance, smaller volumes for the Antactic ice-sheet. This last point interfers with the estimate of present-day ice-melting in Antarctica from GRACE data. Finally, we find that P2 with Burgers rheology favors the existence of a tectosphere, i.e. a viscous sublithospheric layer.

  6. Improved PWM control for GTO inverters with pulse number modulation

    SciTech Connect

    Tadakuma, Susuma; Tanaka, Shigeru; Miura, Kazutoshi; Ofosu-Amaah, W.

    1996-05-01

    This paper proposes pulse number modulation (PNM)-assisted pulse-width modulation (PWM) control to improve the modulation factor of bridge inverters and to solve voltage uncontrollability in neutral point clamped (NPC) inverters. The basic idea is to enlarge the linear region of PWM control via PNM technology. The authors will show the following through simulation and experimental results: (1) conventional bridge inverters can utilize at most 80% of the nominal inverter capacity because of the limit of the modulation factor. The PWM and PNM combined control is able to improve the modulation factor up to approximately 1.0; (2) the PWM and PNM control enables linear voltage control in the NPC inverter even for an extremely small reference. The PNM technology also contributes to a reduction in switching losses.

  7. Phase-dependent high refractive index without absorption in a four-level inverted-Y atomic system

    SciTech Connect

    Zhi-Qiang Zeng; Fu-Ti Liu; Yu-Ping Wang; Zeng-Hui Gao

    2015-01-31

    We consider a closed four-level inverted-Y system in the presence and the absence of a microwave field. It is found that due to the quantum coherence between the two lower levels, either induced by the spontaneous decay or by the microwave field, the refraction – absorption properties of the system can be modulated by controlling the relative phase of the applied fields in both driven ways. In particular, by properly setting the values of the relative phase, the desirable high index of refraction without absorption can be achieved. (nonlinear optical phenomena)

  8. Neuronal loss of Drosophila NPC1a causes cholesterol aggregation and age-progressive neurodegeneration.

    PubMed

    Phillips, Scott E; Woodruff, E A; Liang, Ping; Patten, Meaghan; Broadie, Kendal

    2008-06-25

    The mistrafficking and consequent cytoplasmic accumulation of cholesterol and sphingolipids is linked to multiple neurodegenerative diseases. One class of disease, the sphingolipid storage diseases, includes Niemann-Pick disease type C (NPC), caused predominantly (95%) by mutation of the NPC1 gene. A disease model has been established through mutation of Drosophila NPC1a (dnpc1a). Null mutants display early lethality attributable to loss of cholesterol-dependent ecdysone steroid hormone production. Null mutants rescued to adults by restoring ecdysone production mimic human NPC patients with progressive motor defects and reduced life spans. Analysis of dnpc1a null brains shows elevated overall cholesterol levels and progressive accumulation of filipin-positive cholesterol aggregates within brain and retina, as well as isolated cultured brain neurons. Ultrastructural imaging of dnpc1a mutant brains reveals age-progressive accumulation of striking multilamellar and multivesicular organelles, preceding the onset of neurodegeneration. Consistently, electroretinogram recordings show age-progressive loss of phototransduction and photoreceptor synaptic transmission. Early lethality, movement impairments, neuronal cholesterol deposits, accumulation of multilamellar bodies, and age-dependent neurodegeneration are all rescued by targeted neuronal expression of a wild-type dnpc1a transgene. Interestingly, targeted expression of dnpc1a in glia also provides limited rescue of adult lethality. Generation of dnpc1a null mutant neuron clones in the brain reveals cell-autonomous requirements for dNPC1a in cholesterol and membrane trafficking. These data demonstrate a requirement for dNPC1a in the maintenance of neuronal function and viability and show that loss of dNPC1a in neurons mimics the human neurodegenerative condition. PMID:18579730

  9. Neuronal Loss of Drosophila NPC1a Causes Cholesterol Aggregation and Age-Progressive Neurodegeneration

    PubMed Central

    Phillips, Scott E.; Woodruff, E. A.; Liang, Ping; Patten, Meaghan; Broadie, Kendal

    2009-01-01

    The mistrafficking and consequent cytoplasmic accumulation of cholesterol and sphingolipids is linked to multiple neurodegenerative diseases. One class of disease, the sphingolipid storage diseases, includes Niemann-Pick Disease Type C (NPC) caused predominantly (95%) by mutation of the NPC1 gene. A disease model has been established through mutation of Drosophila NPC1a (dnpc1a). Null mutants display early lethality due to loss of cholesterol-dependent ecdysone steroid hormone production. Null mutants rescued to adults by restoring ecdysone production mimic human NPC patients with progressive motor defects and reduced life spans. Analysis of dnpc1a null brains shows elevated overall cholesterol levels and progressive accumulation of filipin-positive cholesterol aggregates within brain and retina, as well as isolated cultured brain neurons. Ultrastructural imaging of dnpc1a mutant brains reveals age-progressive accumulation of striking multilamellar and multivesicular organelles, preceding the onset of neurodegeneration. Consistently, electroretinogram (ERG) recordings show age-progressive loss of phototransduction and photoreceptor synaptic transmission. Early lethality, movement impairments, neuronal cholesterol deposits, accumulation of multilamellar bodies and age-dependent neurodegeneration are all rescued by targeted neuronal expression of a wildtype dnpc1a transgene. Interestingly, targeted expression of dnpc1a in glia also provides limited rescue of adult lethality. Generation of dnpc1a null mutant neuron clones in the brain reveals cell autonomous requirements for dNPC1a in cholesterol and membrane trafficking. These data demonstrate a requirement for dNPC1a in the maintenance of neuronal function and viability, and show that loss of dNPC1a in neurons mimics the human neurodegenerative condition. PMID:18579730

  10. Diagnostic tests for Niemann-Pick disease type C (NP-C): A critical review.

    PubMed

    Vanier, Marie T; Gissen, Paul; Bauer, Peter; Coll, Maria J; Burlina, Alberto; Hendriksz, Christian J; Latour, Philippe; Goizet, Cyril; Welford, Richard W D; Marquardt, Thorsten; Kolb, Stefan A

    2016-08-01

    Niemann-Pick disease type C (NP-C) is a neurovisceral lysosomal cholesterol trafficking and lipid storage disorder caused by mutations in one of the two genes, NPC1 or NPC2. Diagnosis has often been a difficult task, due to the wide range in age of onset of NP-C and clinical presentation of the disease, combined with the complexity of the cell biology (filipin) laboratory testing, even in combination with genetic testing. This has led to substantial delays in diagnosis, largely depending on the access to specialist centres and the level of knowledge about NP-C of the physician in the area. In recent years, advances in mass spectrometry has allowed identification of several sensitive plasma biomarkers elevated in NP-C (e.g. cholestane-3β,5α,6β-triol, lysosphingomyelin isoforms and bile acid metabolites), which, together with the concomitant progress in molecular genetic technology, have greatly impacted the strategy of laboratory testing. Specificity of the biomarkers is currently under investigation and other pathologies are being found to also result in elevations. Molecular genetic testing also has its limitations, notably with unidentified mutations and the classification of new variants. This review is intended to increase awareness on the currently available approaches to laboratory diagnosis of NP-C, to provide an up to date, comprehensive and critical evaluation of the various techniques (cell biology, biochemical biomarkers and molecular genetics), and to briefly discuss ongoing/future developments. The use of current tests in proper combination enables a rapid and correct diagnosis in a large majority of cases. However, even with recent progress, definitive diagnosis remains challenging in some patients, for whom combined genetic/biochemical/cytochemical markers do not provide a clear answer. Expertise and reference laboratories thus remain essential, and further work is still required to fulfill unmet needs. PMID:27339554

  11. Modes competition in superradiant emission from an inverted sub-wavelength thick slab of two-level atoms

    NASA Astrophysics Data System (ADS)

    Manassah, Jamal T.

    2016-08-01

    Using the expansion in the eigenmodes of 1-D Lienard-Wiechert kernel, the temporal and spectral profiles of the radiation emitted by a fully inverted collection of two-level atoms in a sub-wavelength slab geometry are computed. The initial number of amplifying modes determine the specific regime of radiation. In particular, the temporal profile of the field intensity is oscillatory and the spectral profile is non-Lorentzian with two unequal height peaks in a narrow band centered at the slab thickness value at which the real parts of the lowest order odd and even eigenvalues are equal.

  12. An advanced static var compensator based on a three level IGBT inverter modelling analysis and active power filtering

    NASA Astrophysics Data System (ADS)

    Draou, Azeddine

    2012-12-01

    This paper presents the dynamic performance analysis of an Advanced Static Var Compensator (ASVC) using three-level neutral point-clamped voltage source inverter. The paper presents the principles of operating and the method of reference currents generation. The dynamic behaviour of the system is further analysed using Matlab/Simulink with SimPower Systems toolbox through a set of simulation tests. The results obtained have been applied to an active power filter which might lead to the design of a robust controller for current harmonics and reactive power applications

  13. RNA Export through the NPC in Eukaryotes.

    PubMed

    Okamura, Masumi; Inose, Haruko; Masuda, Seiji

    2015-01-01

    In eukaryotic cells, RNAs are transcribed in the nucleus and exported to the cytoplasm through the nuclear pore complex. The RNA molecules that are exported from the nucleus into the cytoplasm include messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), micro RNAs (miRNAs), and viral mRNAs. Each RNA is transported by a specific nuclear export receptor. It is believed that most of the mRNAs are exported by Nxf1 (Mex67 in yeast), whereas rRNAs, snRNAs, and a certain subset of mRNAs are exported in a Crm1/Xpo1-dependent manner. tRNAs and miRNAs are exported by Xpot and Xpo5. However, multiple export receptors are involved in the export of some RNAs, such as 60S ribosomal subunit. In addition to these export receptors, some adapter proteins are required to export RNAs. The RNA export system of eukaryotic cells is also used by several types of RNA virus that depend on the machineries of the host cell in the nucleus for replication of their genome, therefore this review describes the RNA export system of two representative viruses. We also discuss the NPC anchoring-dependent mRNA export factors that directly recruit specific genes to the NPC. PMID:25802992

  14. RNA Export through the NPC in Eukaryotes

    PubMed Central

    Okamura, Masumi; Inose, Haruko; Masuda, Seiji

    2015-01-01

    In eukaryotic cells, RNAs are transcribed in the nucleus and exported to the cytoplasm through the nuclear pore complex. The RNA molecules that are exported from the nucleus into the cytoplasm include messenger RNAs (mRNAs), ribosomal RNAs (rRNAs), transfer RNAs (tRNAs), small nuclear RNAs (snRNAs), micro RNAs (miRNAs), and viral mRNAs. Each RNA is transported by a specific nuclear export receptor. It is believed that most of the mRNAs are exported by Nxf1 (Mex67 in yeast), whereas rRNAs, snRNAs, and a certain subset of mRNAs are exported in a Crm1/Xpo1-dependent manner. tRNAs and miRNAs are exported by Xpot and Xpo5. However, multiple export receptors are involved in the export of some RNAs, such as 60S ribosomal subunit. In addition to these export receptors, some adapter proteins are required to export RNAs. The RNA export system of eukaryotic cells is also used by several types of RNA virus that depend on the machineries of the host cell in the nucleus for replication of their genome, therefore this review describes the RNA export system of two representative viruses. We also discuss the NPC anchoring-dependent mRNA export factors that directly recruit specific genes to the NPC. PMID:25802992

  15. Milliwatt dc/dc Inverter

    NASA Technical Reports Server (NTRS)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  16. Inverting the Linear Algebra Classroom

    ERIC Educational Resources Information Center

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  17. Genetic variation at the NPC1L1 gene locus, plasma lipoproteins, and heart disease risk in the elderly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Niemann-Pick C1-like 1 protein (NPC1L1) plays a critical role in intestinal cholesterol absorption. Our objective was to examine whether five variants (-133A>G, -18A>C, L272L, V1296V, and U3_28650A>G) at the NPC1L1 gene have effects on lipid levels, prevalence, and incidence of coronary heart diseas...

  18. Niemann-Pick C1-Like 1 (NPC1L1) Inhibition and Cardiovascular Diseases.

    PubMed

    Pirillo, A; Catapano, A L; Norata, G D

    2016-01-01

    Circulating levels of cholesterol are derived from either endogenous production or intestinal absorption of dietary and biliary cholesterol. Niemann-Pick C1-Like 1 (NPC1L1) is a transmembrane protein that plays a key role in the intestinal absorption of cholesterol by facilitating its uptake through vesicular endocytosis. NPC1L1 is the molecular target of ezetimibe which binds its extracellular loop and inhibits sterol absorption without affecting the absorption of other molecules. Ezetimibe significantly reduces plasma levels of total and low density lipoprotein cholesterol (LDL-C) as monotherapy or when added to statins, the association with a low dose of statin is of particular interest for patients experiencing statin-related side effects. The recent results of the IMPROVE-IT study, which evaluated the cardiovascular effect of ezetimibe added to simvastatin therapy in subjects who had had an acute coronary syndrome and with LDL-C levels within the recommended range, showed that a further LDL-C lowering reduced the incidence of cardiovascular events. To date, ezetimibe represents the only inhibitor of NPC1L1 available for clinical use, however, novel aminoß- lactam ezetimibe derivatives have been synthesized and their efficacy to inhibit NPC1L1 protein and decrease plasma cholesterol levels is under evaluation. PMID:26923679

  19. Pulmonary function and pathology in hydroxypropyl-beta-cyclodextin-treated and untreated Npc1⁻/⁻ mice.

    PubMed

    Muralidhar, Akshay; Borbon, Ivan A; Esharif, Dyadin M; Ke, Wangjing; Manacheril, Rinu; Daines, Michael; Erickson, Robert P

    2011-06-01

    Lung dysfunction is an important part of the pathology of the neurodegenerative disorder, Niemann-Pick C1 (NPC1). We have studied the pulmonary disease in the Npc1(NIH/NIH) mouse model. On histology, we find large numbers of alveolar foamy macrophages but no alveolar proteinosis. Lung weight as percent of body weight was markedly increased; using the flexiVent small animal ventilator (SCIREQ, Inc.), we find inspiratory capacity, elastance and hysterisivity to be increased while resistance was not changed. Cholesterol measurements show a doubling of lung cholesterol levels. Collagen is also increased. Treatment of Npc1(-/-) mice with hydroxypropyl-β-cyclodextrin (HPBCD), despite efficacious effects in brain and liver, results in little difference from age-matched controls (using a CNS-expressed transgene to extend the life expectancy of the Npc1(-/-) mice) for these variables. PMID:21459030

  20. A DC-Voltage-Balancing Circuit for a Five-Level Diode-Clamped PWM Inverter Intended for Motor Drives

    NASA Astrophysics Data System (ADS)

    Hasegawa, Kazunori; Akagi, Hirofumi

    This paper proposes a new dc-voltage-balancing circuit for a five-level diode-clamped inverter intended for a medium-voltage motor drive. This circuit consists of two unidirectional choppers and a single coupled inductor with two galvanically-isolated windings. The dc magnetic fluxes in the magnetic core, which are generated by the two windings, cancel out each other. Therefore, the inductor does not generate any dc-magnetic flux in the magnetic core. This makes the inductor compact by a factor of six compared to previously used balancing circuits containing two non-coupled inductors. Experimental results obtained from a 200-V 5.5-kW downscaled model verify that the dc mean voltages of the four split dc capacitors are balanced well under all operating conditions.

  1. The NPC: A Higher Priority for Networking Policy

    ERIC Educational Resources Information Center

    Kuhns, Jeff C.

    2006-01-01

    This article discusses the scope of activities of the Network Policy Council (NPC), which has been designed to provide a more direct channel of communications within EDUCAUSE and to provide policy formulation more visibility. The NPC is an advisory council to EDUCAUSE whose members are selected from those who have interest in this area and are…

  2. Cholesterol signaling at the endoplasmic reticulum occurs in npc1(-/-) but not in npc1(-/-), LDLR(-/-) mice.

    PubMed

    Erickson, R P; Kiela, M; Garver, W S; Krishnan, K; Heidenreich, R A

    2001-06-01

    It remains controversial whether deficiency of the Niemann-Pick C1 (npc1) protein results in altered cholesterol signaling at the endoplasmic reticulum (ER). In this report, we have measured the processed, nuclear form of sterol regulatory element binding protein (SREBP)-1 in livers of npc1 wild-type, heterozygous, and homozygous deficient mice, alone, and in combination with deficiencies of the low density lipoprotein receptor (LDLR) or the multiple drug resistant (mdr)1a, P-glycoprotein. Cleavage of SREBPs to activated forms normally occurs when the ER is deficient in cholesterol. A large decrease in processed SREBP-1 was evident in fasted npc1(-/-) mice and npc1(-/-), mdr1a(-/-) mice, with no decrease evident in npc1(-/-), LDLR(-/-) mice. These results suggest that the increase in cellular cholesterol which occurs in npc1(-/-) and in npc1(-/-), mdr1a(-/-) mice includes the sites responsible for cholesterol signaling, while the similar increase in cholesterol found in npc1(-/-), LDLR(-/-) mice does not. PMID:11394880

  3. Epigenetic modulation of intestinal cholesterol transporter Niemann-Pick C1-like 1 (NPC1L1) gene expression by DNA methylation.

    PubMed

    Malhotra, Pooja; Soni, Vinay; Kumar, Anoop; Anbazhagan, Arivarasu N; Dudeja, Amish; Saksena, Seema; Gill, Ravinder K; Dudeja, Pradeep K; Alrefai, Waddah A

    2014-08-15

    Intestinal NPC1L1 transporter is essential for cholesterol absorption and the maintenance of cholesterol homeostasis in the body. NPC1L1 is differentially expressed along the gastrointestinal tract with very low levels in the colon as compared with the small intestine. This study was undertaken to examine whether DNA methylation was responsible for segment-specific expression of NPC1L1. Treatment of mice with 5-azacytidine (i.p.) resulted in a significant dose-dependent increase in NPC1L1 mRNA expression in the colon. The lack of expression of NPC1L1 in the normal colon was associated with high levels of methylation in the area flanking the 3-kb fragment upstream of the initiation site of the mouse NPC1L1 gene in mouse colon as analyzed by EpiTYPER® MassARRAY®. The high level of methylation in the colon was observed in specific CpG dinucleotides and was significantly decreased in response to 5-azacytidine. Similar to mouse NPC1L1, 5-azacytidine treatment also increased the level of human NPC1L1 mRNA expression in the intestinal HuTu-80 cell line in a dose- and time-dependent manner. Silencing the expression of DNA methyltransferase DNMT1, -2, -3A, and -3B alone by siRNA did not affect NPC1L1 expression in HuTu-80 cells. However, the simultaneous attenuation of DNMT1 and -3B expression caused a significant increase in NPC1L1 mRNA expression as compared with control. Also, in vitro methylation of the human NPC1L1 promoter significantly decreased NPC1L1 promoter activity in human intestinal Caco2 cells. In conclusion, our data demonstrated for the first time that DNA methylation in the promoter region of the NPC1L1 gene appears to be a major mechanism underlying differential expression of NPC1L1 along the length of the gastrointestinal tract. PMID:24904062

  4. A low-power inverter-based CMOS level-crossing analog-to-digital converter for low-frequency biosignal sensing

    NASA Astrophysics Data System (ADS)

    Tanaka, Suiki; Niitsu, Kiichi; Nakazato, Kazuo

    2016-03-01

    Low-power analog-to-digital conversion is a key technique for power-limited biomedical applications such as power-limited continuous glucose monitoring. However, a conventional uniform-sampling analog-to-digital converter (ADC) is not suitable for nonuniform biosignals. A level-crossing ADC (LC-ADC) is a promising candidate for low-power biosignal processing because of its event-driven properties. The LC-ADC acquires data by level-crossing sampling. When an input signal crosses the threshold level, the LC-ADC samples the signal. The conventional LC-ADC employs a power-hungry comparator. In this paper, we present a low-power inverter-based LC-ADC. By adjusting the threshold level of the inverter, it can be used as a threshold-fixed window comparator. By using the inverter as an alternative to a comparator, power consumption can be markedly reduced. As a result, the total power consumption is successfully reduced by 90% of that of previous LC-ADC. The inverter-based LC-ADC was found to be very suitable for use in power-limited biomedical devices.

  5. Multilevel DC link inverter

    DOEpatents

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  6. A method for predicting the noise levels of coannular jets with inverted velocity profiles

    NASA Technical Reports Server (NTRS)

    Russell, J. W.

    1979-01-01

    A coannular jet was equated with a single stream equivalent jet with the same mass flow, energy, and thrust. The acoustic characteristics of the coannular jet were then related to the acoustic characteristics of the single jet. Forward flight effects were included by incorporating a forward exponent, a Doppler amplification factor, and a Strouhal frequency shift. Model test data, including 48 static cases and 22 wind tunnel cases, were used to evaluate the prediction method. For the static cases and the low forward velocity wind tunnel cases, the spectral mean square pressure correlation coefficients were generally greater than 90 percent, and the spectral sound pressure level standard deviation were generally less than 3 decibels. The correlation coefficient and the standard deviation were not affected by changes in equivalent jet velocity. Limitations of the prediction method are also presented.

  7. Inverted Barometer Contributions to Accelerated and Extreme Annual Mean Sea Level Changes Along the East Coast of North America

    NASA Astrophysics Data System (ADS)

    Piecuch, C. G.; Ponte, R. M.

    2015-12-01

    Recent works have interpreted accelerated and extreme sea level (SL) changes along the northeast coast of North America primarily in terms of dynamic changes related to the meridional overturning or coastal circulations. Isostatic changes related to surface atmospheric pressure loading —the inverted barometer (IB) effect— have been deemed relatively unimportant, but a comprehensive analysis of the IB effect has been lacking. In this work, we use five different atmospheric pressure products to analyze the influence of the IB effect on annual mean SL from tide gauge records. Consistently across all products, the IB effect accounts for about 50% of the magnitude of a recent extreme event of SL rise in 2009 along Atlantic Canada and New England. In fact, the unique nature of the event was largely a result of the extreme IB signal. Estimated IB effects also amount to about 10-30% of recent multidecadal SL accelerations over the Mid-Atlantic Bight and Southern New England. These findings reiterate the need for careful estimation of IB effects for studies that want to interpret observed SL in terms of dynamic ocean circulation changes.

  8. Structure of glycosylated NPC1 luminal domain C reveals insights into NPC2 and Ebola virus interactions.

    PubMed

    Zhao, Yuguang; Ren, Jingshan; Harlos, Karl; Stuart, David I

    2016-03-01

    Niemann-pick type C1 (NPC1) is an endo/lysosomal membrane protein involved in intracellular cholesterol trafficking, and its luminal domain C is an essential endosomal receptor for Ebola and Marburg viruses. We have determined the crystal structure of glycosylated NPC1 luminal domain C and find all seven possible sites are glycosylated. Mapping the disease mutations onto the glycosylated structure reveals a potential binding face for NPC2. Knowledge-based docking of NPC1 onto Ebola viral glycoprotein and sequence analysis of filovirus susceptible and refractory species reveals four critical residues, H418, Q421, F502 and F504, some or all of which are likely responsible for the species-specific susceptibility to the virus infection. PMID:26846330

  9. Capsaicin mediates apoptosis in human nasopharyngeal carcinoma NPC-TW 039 cells through mitochondrial depolarization and endoplasmic reticulum stress.

    PubMed

    Ip, S-W; Lan, S-H; Lu, H-F; Huang, A-C; Yang, J-S; Lin, J-P; Huang, H-Y; Lien, J-C; Ho, C-C; Chiu, C-F; Wood, Wg; Chung, J-G

    2012-06-01

    Capsaicin, a pungent compound found in hot chili peppers, has been reported to have antitumor activities in many human cancer cell lines, but the induction of precise apoptosis signaling pathway in human nasopharyngeal carcinoma (NPC) cells is unclear. Here, we investigated the molecular mechanisms of capsaicin-induced apoptosis in human NPC, NPC-TW 039, cells. Effects of capsaicin involved endoplasmic reticulum (ER) stress, caspase-3 activation and mitochondrial depolarization. Capsaicin-induced cytotoxic effects (cell death) through G0/G1 phase arrest and induction of apoptosis of NPC-TW 039 cells in a dose-dependent manner. Capsaicin treatment triggered ER stress by promoting the production of reactive oxygen species (ROS), increasing levels of inositol-requiring 1 enzyme (IRE1), growth arrest and DNA-damage-inducible 153 (GADD153) and glucose-regulated protein 78 (GRP78). Other effects included an increase in cytosolic Ca(2+), loss of the mitochondrial transmembrane potential (ΔΨ(m)), releases of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9 and -3. Furthermore, capsaicin induced increases in the ratio of Bax/Bcl-2 and abundance of apoptosis-related protein levels. These results suggest that ER stress- and mitochondria-mediated cell death is involved in capsaicin-induced apoptosis in NPC-TW 039 cells. PMID:21859781

  10. Simplified High-Power Inverter

    NASA Technical Reports Server (NTRS)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  11. Applications of cascade multilevel inverters.

    PubMed

    Peng, Fang-zen; Qian, Zhao-ming

    2003-01-01

    Cascade multilevel inverters have been developed for electric utility applications. A cascade M-level inverter consists of (M-1)/2 H-bridges in which each bridge's dc voltage is supported by its own dc capacitor. The new inverter can: (1) generate almost sinusoidal waveform voltage while only switching one time per fundamental cycle; (2) dispense with multi-pulse inverters' transformers used in conventional utility interfaces and static var compensators; (3) enables direct parallel or series transformer-less connection to medium- and high-voltage power systems. In short, the cascade inverter is much more efficient and suitable for utility applications than traditional multi-pulse and pulse width modulation (PWM) inverters. The authors have experimentally demonstrated the superiority of the new inverter for power supply, (hybrid) electric vehicle (EV) motor drive, reactive power (var) and harmonic compensation. This paper summarizes the features, feasibility, and control schemes of the cascade inverter for utility applications including utility interface of renewable energy, voltage regulation, var compensation, and harmonic filtering in power systems. Analytical, simulated, and experimental results demonstrated the superiority of the new inverters. PMID:14566981

  12. Over-expression of miR-10b in NPC patients: correlation with LMP1 and Twist1.

    PubMed

    Allaya, Nesrine; Khabir, Abdelmajid; Sallemi-Boudawara, Tahia; Sellami, Noura; Daoud, Jamel; Ghorbel, Abdelmonem; Frikha, Mounir; Gargouri, Ali; Mokdad-Gargouri, Raja; Ayadi, Wajdi

    2015-05-01

    Aberrant expression of miR-10b has been described in many cancers but remains unexplored in nasopharyngeal carcinoma (NPC). Therefore, we aimed to study the miR-10b expression level in 43 NPC biopsies collected from Tunisian patients and three NPC xenografts. Then, we investigated the correlation between miR-10b expression and its upstream regulators LMP1/Twist1 as well as its adjacent gene HoxD4. We showed that miR-10b was significantly up-regulated in NPC biopsies compared to non-tumor nasopharyngeal tissues (fold change 153; p = 0.004) and associated with advanced clinical stage and young age at diagnosis (p = 0.005 and p = 0.011, respectively). In addition, over-expression of miR-10b was positively associated with the transcription factor Twist1 as well as the EBV oncoprotein LMP1 (fold change 6.32; p = 0.014, fold change 6.58; p = 0.01 respectively). Furthermore, higher level of miR-10b was observed in tumors with simultaneous expression of LMP1 and Twist1, compared to those expressing only Twist1 (fold change 2.49; p = 0.033). Meanwhile, the analysis of the link between miR-10b and its neighbor gene HoxD4 did not show any significant correlation (Fisher test p = 0.205; Mann-Whitney test p = 0.676). This study reports the first evidence of miR-10b over-expression in NPC patients. Furthermore, our findings can support hsa-miR-10b gene regulation through LMP1/Twist1 in NPC malignancy. PMID:25597482

  13. Ebolavirus Glycoprotein Directs Fusion through NPC1+ Endolysosomes

    PubMed Central

    Simmons, James A.; D'Souza, Ryan S.; Ruas, Margarida; Galione, Antony; Casanova, James E.

    2015-01-01

    Ebolavirus, a deadly hemorrhagic fever virus, was thought to enter cells through endolysosomes harboring its glycoprotein receptor, Niemann-Pick C1. However, an alternate model was recently proposed in which ebolavirus enters through a later NPC1-negative endosome that contains two-pore Ca2+ channel 2 (TPC2), a newly identified ebolavirus entry factor. Here, using live cell imaging, we obtained evidence that in contrast to the new model, ebolavirus enters cells through endolysosomes that contain both NPC1 and TPC2. PMID:26468524

  14. Segmentation of nasopharyngeal carcinoma (NPC) lesions in MR images

    SciTech Connect

    Lee, Francis K.H. . E-mail: fkhlee@cuhk.edu.hk; Yeung, David K.W.; King, Ann D.; Leung, S.F.; Ahuja, Anil

    2005-02-01

    Purpose: An accurate and reproducible method to delineate tumor margins from uninvolved tissues is of vital importance in guiding radiation therapy (RT). In nasopharyngeal carcinoma (NPC), tumor margin may be difficult to identify in magnetic resonance (MR) images, making the task of optimizing RT treatment more difficult. Our aim in this study is to develop a semiautomatic image segmentation method for NPC that requires minimal human intervention and is capable of delineating tumor margins with good accuracy and reproducibility. Methods and materials: The segmentation algorithm includes 5 stages: masking, Bayesian probability calculation, smoothing, thresholding and seed growing, and finally dilation and overlaying of results with different thresholds. The algorithm is based on information obtained from the contrast enhancement ratio of T1-weighted images and signal intensity of T2-weighted images. The algorithm is initiated by the selection of a valid anatomical seed point within the tumor by the user. The algorithm was evaluated on MR images from 7 NPC patients and was compared against the radiologist's reference outline. Results: The algorithm was successfully implemented on all 7 subjects. With a threshold of 1, the average percent match is 78.5 {+-} 3.86 (standard deviation) %, and the correspondence ratio is 66.5 {+-} 7%. Discussion: The segmentation algorithm presented here may be useful for diagnosing NPC and may guide RT treatment planning. Further improvement will be desirable to improve the accuracy and versatility of the method.

  15. Quantitative Proteomics of Human Fibroblasts with I1061T Mutation in Niemann–Pick C1 (NPC1) Protein Provides Insights into the Disease Pathogenesis*

    PubMed Central

    Rauniyar, Navin; Subramanian, Kanagaraj; Lavallée-Adam, Mathieu; Martínez-Bartolomé, Salvador; Balch, William E.; Yates, John R.

    2015-01-01

    Niemann-Pick type C (NPC) disease is a fatal neurodegenerative disorder characterized by the accumulation of unesterified cholesterol in the late endosomal/lysosomal compartments. Mutations in the NPC1 protein are implicated in 95% of patients with NPC disease. The most prevalent mutation is the missense mutation I1061T that occurs in ∼15–20% of the disease alleles. In our study, an isobaric labeling-based quantitative analysis of proteome of NPC1I1061T primary fibroblasts when compared with wild-type cells identified 281 differentially expressed proteins based on stringent data analysis criteria. Gene ontology enrichment analysis revealed that these proteins play important roles in diverse cellular processes such as protein maturation, energy metabolism, metabolism of reactive oxygen species, antioxidant activity, steroid metabolism, lipid localization, and apoptosis. The relative expression level of a subset of differentially expressed proteins (TOR4A, DHCR24, CLGN, SOD2, CHORDC1, HSPB7, and GAA) was independently and successfully substantiated by Western blotting. We observed that treating NPC1I1061T cells with four classes of seven different compounds that are potential NPC drugs increased the expression level of SOD2 and DHCR24. We have also shown an abnormal accumulation of glycogen in NPC1I1061T fibroblasts possibly triggered by defective processing of lysosomal alpha-glucosidase. Our study provides a starting point for future more focused investigations to better understand the mechanisms by which the reported dysregulated proteins triggers the pathological cascade in NPC, and furthermore, their effect upon therapeutic interventions. PMID:25873482

  16. Overload protection system for power inverter

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1977-01-01

    An overload protection system for a power inverter utilized a first circuit for monitoring current to the load from the power inverter to detect an overload and a control circuit to shut off the power inverter, when an overload condition was detected. At the same time, a monitoring current inverter was turned on to deliver current to the load at a very low power level. A second circuit monitored current to the load, from the monitoring current inverter, to hold the power inverter off through the control circuit, until the overload condition was cleared so that the control circuit may be deactivated in order for the power inverter to be restored after the monitoring current inverter is turned off completely.

  17. Stream, Inverted

    NASA Technical Reports Server (NTRS)

    2006-01-01

    27 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the inverted, eroded remains of a channel -- now standing as a complex ridge that runs across the middle of this scene -- in dust-mantled terrain west of Sinus Meridiani, Mars. The original channel might have been carved by running water, but too little detail remains today to provide any certainty as to whether water was the culprit.

    Location near: 5.6oN, 7.6oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Northern Spring

  18. Power inverters

    SciTech Connect

    Miller, David H.; Korich, Mark D.; Smith, Gregory S.

    2011-11-15

    Power inverters include a frame and a power module. The frame has a sidewall including an opening and defining a fluid passageway. The power module is coupled to the frame over the opening and includes a substrate, die, and an encasement. The substrate includes a first side, a second side, a center, an outer periphery, and an outer edge, and the first side of the substrate comprises a first outer layer including a metal material. The die are positioned in the substrate center and are coupled to the substrate first side. The encasement is molded over the outer periphery on the substrate first side, the substrate second side, and the substrate outer edge and around the die. The encasement, coupled to the substrate, forms a seal with the metal material. The second side of the substrate is positioned to directly contact a fluid flowing through the fluid passageway.

  19. Ryanodine receptor antagonists adapt NPC1 proteostasis to ameliorate lipid storage in Niemann-Pick type C disease fibroblasts.

    PubMed

    Yu, Ting; Chung, Chan; Shen, Dongbiao; Xu, Haoxing; Lieberman, Andrew P

    2012-07-15

    Niemann-Pick type C disease is a lysosomal storage disorder most often caused by loss-of-function mutations in the NPC1 gene. The encoded multipass transmembrane protein is required for cholesterol efflux from late endosomes and lysosomes. Numerous missense mutations in the NPC1 gene cause disease, including the prevalent I1061T mutation that leads to protein misfolding and degradation. Here, we sought to modulate the cellular proteostasis machinery to achieve functional recovery in primary patient fibroblasts. We demonstrate that targeting endoplasmic reticulum (ER) calcium levels using ryanodine receptor (RyR) antagonists increased steady-state levels of the NPC1 I1061T protein. These compounds also promoted trafficking of mutant NPC1 to late endosomes and lysosomes and rescued the aberrant storage of cholesterol and sphingolipids that is characteristic of disease. Similar rescue was obtained using three distinct RyR antagonists in cells with missense alleles, but not with null alleles, or by over-expressing calnexin, a calcium-dependent ER chaperone. Our work highlights the utility of proteostasis regulators to remodel the protein-folding environment in the ER to recover function in the setting of disease-causing missense alleles. PMID:22505584

  20. The c.-133A > G polymorphism in NPC1L1 gene influences the efficacy of ezetimibe monotherapy on apolipoprotein A1 in hyperlipidemic patients.

    PubMed

    Zsíros, N; Bodor, M; Varga, V; Berta, E; Balogh, I; Seres, I; Paragh, G; Harangi, M

    2014-06-01

    Niemann-Pick C1-like 1 protein (NPC1L1) plays a critical role in intestinal cholesterol absorption. Previous studies found that the NPC1L1 c.-133A > G SNP, but not other NPC1L1 SNPs, was associated with response to statin treatment and statin-ezetimibe combinations. To date effect of NPC1L1 c.-133A > G SNP on ezetimibe monotherapy has not been studied. Our objective was to examine whether SNP c.-133A > G at the NPC1L1 gene has effects on lipid levels and on the efficacy of 3, 6 and 12 months of 10 mg daily ezetimibe monotherapy in hyperlipidemic patients with statin induced adverse effects. One hundred and one type IIa and IIb hyperlipidemic patients (72 females, 29 males; age: 61.23 +/- 9.87 ys; BMI: 28.18 +/- 4.29 kg/m2) were enrolled. The genotype frequencies were conformed to Hardy-Weinberg equilibrium. We could not find significant differences in initial lipid levels between AA and AG + GG patients. While plasma levels of apolipoprotein A1 (ApoA1) did not significantly decrease after ezetimibe treatment (1.96; 3.39 and 2.74%) in AA patients, a significant elevation in ApoA1 levels has been found after treatment in AG + GG patients (9.15; 8.54 and 13.58%). The effect of NPC1L1 c.-133A > G on the ApoA1 levels was found significant (p < 0.05). Efficacy of treatment with ezetimibe on other plasma lipid parameters after 3, 6 or 12 months did not differ significantly. NPC1L1-133A > G SNP influences the ApoA1 response to ezetimibe monotherapy, therefore, may alter the effect of ezetimibe on the structure and function of the high-density lipoprotein particles. PMID:24974575

  1. NPC1L1 is a key regulator of intestinal vitamin K absorption and a modulator of warfarin therapy.

    PubMed

    Takada, Tappei; Yamanashi, Yoshihide; Konishi, Kentaro; Yamamoto, Takehito; Toyoda, Yu; Masuo, Yusuke; Yamamoto, Hideaki; Suzuki, Hiroshi

    2015-02-18

    Vitamin K (VK) is a micronutrient that facilitates blood coagulation. VK antagonists, such as warfarin, are used in the clinic to prevent thromboembolism. Because VK is not synthesized in the body, its intestinal absorption is crucial for maintaining whole-body VK levels. However, the molecular mechanism of this absorption is unclear. We demonstrate that Niemann-Pick C1-like 1 (NPC1L1) protein, a cholesterol transporter, plays a central role in intestinal VK uptake and modulates the anticoagulant effect of warfarin. In vitro studies using NPC1L1-overexpressing intestinal cells and in vivo studies with Npc1l1-knockout mice revealed that intestinal VK absorption is NPC1L1-dependent and inhibited by ezetimibe, an NPC1L1-selective inhibitor clinically used for dyslipidemia. In addition, in vivo pharmacological studies demonstrated that the coadministration of ezetimibe and warfarin caused a reduction in hepatic VK levels and enhanced the pharmacological effect of warfarin. Adverse events caused by the coadministration of ezetimibe and warfarin were rescued by oral VK supplementation, suggesting that the drug-drug interaction effects observed were the consequence of ezetimibe-mediated VK malabsorption. This mechanism was supported by a retrospective evaluation of clinical data showing that, in more than 85% of warfarin-treated patients, the anticoagulant activity was enhanced by cotreatment with ezetimibe. Our findings provide insight into the molecular mechanism of VK absorption. This new drug-drug interaction mechanism between ezetimibe (a cholesterol transport inhibitor) and warfarin (a VK antagonist and anticoagulant) could inform clinical care of patients on these medications, such as by altering the kinetics of essential, fat-soluble vitamins. PMID:25696002

  2. c-Src activation promotes nasopharyngeal carcinoma metastasis by inducing the epithelial-mesenchymal transition via PI3K/Akt signaling pathway: a new and promising target for NPC.

    PubMed

    Ke, Liangru; Xiang, Yanqun; Guo, Xiang; Lu, Jinping; Xia, Weixiong; Yu, Yahui; Peng, Yongjian; Wang, Li; Wang, Gang; Ye, Yanfang; Yang, Jing; Liang, Hu; Kang, Tiebang; Lv, Xing

    2016-05-10

    Aberrant activation of cellular Src (c-Src), a non-receptor tyrosine kinase, could promote cancer progression through activating its downstream signaling pathways. However, the roles of c-Src and phosphorylated-Src (p-Src) in nasopharyngeal carcinoma (NPC) progression are rarely investigated. Herein, we have identified high c-Src concentrations in the serum of NPC patients with distant metastasis using high-throughput protein microarrays. Levels of c-Src in serum and p-Src in human primary NPC samples were unfavorable independent prognostic factors for cancer-specific survival, disease-free survival, and distant metastasis-free survival. Depletion or inactivation of c-Src in NPC cells using sgRNA with CRISPR/Cas9 system or PP2 decreased cell viability, colony formation, migration and invasion in vitro and metastasis in vivo. In contrast, these malignancies could be up-regulated by overexpressed c-Src in a NPC cell line with low-metastasis potential. Furthermore, p-Src was involved in promoting NPC cell metastasis by inducing the epithelial-mesenchymal transition (EMT) process via activating the PI3K/Akt pathway and cytoskeleton remodeling. The p-Src-induced EMT process could be retarded by PP2, which mediated by down-regulating the PI3K/Akt pathway. In conclusion, elevated levels of c-Src in serum and p-Src in primary NPC tissue correlated with poor outcomes of NPC patients. And aberrant activation of c-Src facilitated NPC cells with malignant potential, especially metastasis ability, which mediated by the PI3K/Akt pathway activation and sequentially induced the EMT process. These findings unveiled a promising approach for targeted therapy of advanced NPC. PMID:27078847

  3. Ezetimibe-sensitive cholesterol uptake by NPC1L1 protein does not require endocytosis

    PubMed Central

    Johnson, Tory A.; Pfeffer, Suzanne R.

    2016-01-01

    Human NPC1L1 protein mediates cholesterol absorption in the intestine and liver and is the target of the drug ezetimibe, which is used to treat hypercholesterolemia. Previous studies concluded that NPC1L1-GFP protein trafficking is regulated by cholesterol binding and that ezetimibe blocks NPC1L1-GFP function by inhibiting its endocytosis. We used cell surface biotinylation to monitor NPC1L1-GFP endocytosis and show that ezetimibe does not alter the rate of NPC1L1-GFP endocytosis in cultured rat hepatocytes grown under normal growth conditions. As expected, NPC1L1-GFP endocytosis depends in part on C-terminal, cytoplasmically oriented sequences, but endocytosis does not require cholesterol binding to NPC1L1’s N-terminal domain. In addition, two small- molecule inhibitors of general (and NPC1L1-GFP) endocytosis failed to inhibit the ezetimibe-sensitive uptake of [3H]cholesterol from taurocholate micelles. These experiments demonstrate that cholesterol uptake by NPC1L1 does not require endocytosis; moreover, ezetimibe interferes with NPC1L1’s cholesterol adsorption activity without blocking NPC1L1 internalization in RH7777 cells. PMID:27075173

  4. Ezetimibe-sensitive cholesterol uptake by NPC1L1 protein does not require endocytosis.

    PubMed

    Johnson, Tory A; Pfeffer, Suzanne R

    2016-06-01

    Human NPC1L1 protein mediates cholesterol absorption in the intestine and liver and is the target of the drug ezetimibe, which is used to treat hypercholesterolemia. Previous studies concluded that NPC1L1-GFP protein trafficking is regulated by cholesterol binding and that ezetimibe blocks NPC1L1-GFP function by inhibiting its endocytosis. We used cell surface biotinylation to monitor NPC1L1-GFP endocytosis and show that ezetimibe does not alter the rate of NPC1L1-GFP endocytosis in cultured rat hepatocytes grown under normal growth conditions. As expected, NPC1L1-GFP endocytosis depends in part on C-terminal, cytoplasmically oriented sequences, but endocytosis does not require cholesterol binding to NPC1L1's N-terminal domain. In addition, two small- molecule inhibitors of general (and NPC1L1-GFP) endocytosis failed to inhibit the ezetimibe-sensitive uptake of [(3)H]cholesterol from taurocholate micelles. These experiments demonstrate that cholesterol uptake by NPC1L1 does not require endocytosis; moreover, ezetimibe interferes with NPC1L1's cholesterol adsorption activity without blocking NPC1L1 internalization in RH7777 cells. PMID:27075173

  5. 2.3-MW Medium-Voltage, Three-Level Wind Energy Inverter Applying a Unique Bus Structure and 4.5-kV Si/SiC Hybrid Isolated Power Modules: Preprint

    SciTech Connect

    Erdman, W.; Keller, J.; Grider, D.; VanBrunt, E.

    2014-11-01

    A high-efficiency, 2.3-MW, medium-voltage, three-level inverter utilizing 4.5-kV Si/SiC (silicon carbide) hybrid modules for wind energy applications is discussed. The inverter addresses recent trends in siting the inverter within the base of multimegawatt turbine towers. A simplified split, three-layer laminated bus structure that maintains low parasitic inductances is introduced along with a low-voltage, high-current test method for determining these inductances. Feed-thru bushings, edge fill methods, and other design features of the laminated bus structure provide voltage isolation that is consistent with the 10.4-kV module isolation levels. Inverter efficiency improvement is a result of the (essential) elimination of the reverse recovery charge present in 4.5-kV Si PIN diodes, which can produce a significant reduction in diode turn-off losses as well as insulated-gate bipolar transistor (IGBT) turn-on losses. The hybrid modules are supplied in industry-standard 140 mm x 130 mm and 190 mm x 130 mm packages to demonstrate direct module substitution into existing inverter designs. A focus on laminated bus/capacitor-bank/module subassembly level switching performance is presented.

  6. NREL Pyrheliometer Comparisons: September 22-26, 2014 (NPC-2014)

    SciTech Connect

    Reda, I.; Dooraghi, M.; Habte, A.

    2014-10-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for developing and deploying solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations that are traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a select group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR), and uses these reference instruments to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process. National Renewable Energy Laboratory (NREL) pyrheliometer comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners and operators, each NPC provides an opportunity to determine the unique WRR transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the WRR. NPC-2014 was held September 22-26, 2014. Participants operated 36 absolute cavity radiometers and 22 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal solar irradiance during this period, and this report documents the findings.

  7. Potential effects of NPC1L1 polymorphisms in protecting against clinical disease in a chinese family with sitosterolaemia.

    PubMed

    Hu, Miao; Yuen, Yuet-Ping; Kwok, Jeffrey Ss; Griffith, James F; Tomlinson, Brian

    2014-01-01

    Sitosterolaemia is caused by mutations in either ABCG5 or ABCG8. Chinese and Japanese individuals usually have mutations in ABCG5. We herein report a known and a novel mutation in ABCG8 and their potential interaction with NPC1L1 polymorphisms in a Chinese family with sitosterolaemia. We sequenced ABCG5 and ABCG8 and measured the levels of plasma plant sterols in a 15-year-old Chinese girl with clinical sitosterolaemia (xanthomas with elevated low-density lipoprotein cholesterol (LDL-C) and plant sterols) and her apparently healthy family members. NPC1L1 was sequenced in the genetically affected sibling and other family members. A known mutation, c.490C>T (p. Arg164(*)), in exon 4 and a novel mutation, c.1949T>G (p.Leu650Arg), in exon 13 of ABCG8 were detected in the proband and her sister, who had elevated sterols but low LDL-C levels and no xanthomas. The genetically affected sister, but not the proband, carried two additional heterozygous changes in NPC1L1 (rs2072183 C>G, rs2301935 A>C), which were inherited from the mother, who also had a low LDL-C level. In this study, we detected a known and a novel mutation in ABCG8 in a Chinese patient with sitosterolaemia. The same mutations were found in her clinically normal sister, suggesting that the contrasting features with the proband may be related to different variants in NPC1L1 and/or some other undetermined lipid-related genetic factors. PMID:25056759

  8. Structure of N-Terminal Domain of NPC1 Reveals Distinct Subdomains for Binding and Transfer of Cholesterol

    SciTech Connect

    Kwon, Hyock Joo; Abi-Mosleh, Lina; Wang, Michael L.; Deisenhofer, Johann; Goldstein, Joseph L.; Brown, Michael S.; Infante, Rodney E.

    2010-09-21

    LDL delivers cholesterol to lysosomes by receptor-mediated endocytosis. Exit of cholesterol from lysosomes requires two proteins, membrane-bound Niemann-Pick C1 (NPC1) and soluble NPC2. NPC2 binds cholesterol with its isooctyl side chain buried and its 3{beta}-hydroxyl exposed. Here, we describe high-resolution structures of the N-terminal domain (NTD) of NPC1 and complexes with cholesterol and 25-hydroxycholesterol. NPC1(NTD) binds cholesterol in an orientation opposite to NPC2: 3{beta}-hydroxyl buried and isooctyl side chain exposed. Cholesterol transfer from NPC2 to NPC1(NTD) requires reorientation of a helical subdomain in NPC1(NTD), enlarging the opening for cholesterol entry. NPC1 with point mutations in this subdomain (distinct from the binding subdomain) cannot accept cholesterol from NPC2 and cannot restore cholesterol exit from lysosomes in NPC1-deficient cells. We propose a working model wherein after lysosomal hydrolysis of LDL-cholesteryl esters, cholesterol binds NPC2, which transfers it to NPC1(NTD), reversing its orientation and allowing insertion of its isooctyl side chain into the outer lysosomal membranes.

  9. Npc1 is involved in sterol trafficking in the filamentous fungus Fusarium graminearum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ortholog of the human gene NPC1 was identified in the plant pathogenic, filamentous fungus Fusarium graminearum by shared amino acid sequence, protein domain structure and cellular localization of the mature fungal protein. The Fusarium Npc1 gene shares 34% amino acid sequence identity and 51% s...

  10. Filovirus receptor NPC1 contributes to species-specific patterns of ebolavirus susceptibility in bats.

    PubMed

    Ng, Melinda; Ndungo, Esther; Kaczmarek, Maria E; Herbert, Andrew S; Binger, Tabea; Kuehne, Ana I; Jangra, Rohit K; Hawkins, John A; Gifford, Robert J; Biswas, Rohan; Demogines, Ann; James, Rebekah M; Yu, Meng; Brummelkamp, Thijn R; Drosten, Christian; Wang, Lin-Fa; Kuhn, Jens H; Müller, Marcel A; Dye, John M; Sawyer, Sara L; Chandran, Kartik

    2015-01-01

    Biological factors that influence the host range and spillover of Ebola virus (EBOV) and other filoviruses remain enigmatic. While filoviruses infect diverse mammalian cell lines, we report that cells from African straw-colored fruit bats (Eidolon helvum) are refractory to EBOV infection. This could be explained by a single amino acid change in the filovirus receptor, NPC1, which greatly reduces the affinity of EBOV-NPC1 interaction. We found signatures of positive selection in bat NPC1 concentrated at the virus-receptor interface, with the strongest signal at the same residue that controls EBOV infection in Eidolon helvum cells. Our work identifies NPC1 as a genetic determinant of filovirus susceptibility in bats, and suggests that some NPC1 variations reflect host adaptations to reduce filovirus replication and virulence. A single viral mutation afforded escape from receptor control, revealing a pathway for compensatory viral evolution and a potential avenue for expansion of filovirus host range in nature. PMID:26698106

  11. PHIL Inverter Test Report: Analysis of High-Penetration Levels of PV into the Distribution Grid in California, March 12 - March 16, 2012

    SciTech Connect

    Kromer, M.

    2013-06-01

    This report describes power hardware-in-the-loop simulation testing of a 500 kW Satcon photovoltaic inverter, conducted at the Center for Advanced Power Systems at Florida State University from March 12th through March 16th, 2012. Testing was led by a team from the National Renewable Energy Laboratory. The report reviews the results of data captured during the course of testing. The tests were used to demonstrate operation of and gather data from the inverter in a simulated operational environment. Testing demonstrated the ability of the inverter to operate in either a Power Factor Control Mode or a Reactive Power Command Mode, and to respond to real power limits.

  12. Experimental identification and characterization of 97 novel npcRNA candidates in Salmonella enterica serovar Typhi

    PubMed Central

    Chinni, Suresh V.; Raabe, Carsten A.; Zakaria, Robaiza; Randau, Gerrit; Hoe, Chee Hock; Zemann, Anja; Brosius, Juergen; Tang, Thean-Hock; Rozhdestvensky, Timofey S.

    2010-01-01

    We experimentally identified and characterized 97 novel, non-protein-coding RNA candidates (npcRNAs) from the human pathogen Salmonella enterica serovar Typhi (hereafter referred to as S. typhi). Three were specific to S. typhi, 22 were restricted to Salmonella species and 33 were differentially expressed during S. typhi growth. We also identified Salmonella Pathogenicity Island-derived npcRNAs that might be involved in regulatory mechanisms of virulence, antibiotic resistance and pathogenic specificity of S. typhi. An in-depth characterization of S. typhi StyR-3 npcRNA showed that it specifically interacts with RamR, the transcriptional repressor of the ramA gene, which is involved in the multidrug resistance (MDR) of Salmonella. StyR-3 interfered with RamR–DNA binding activity and thus potentially plays a role in regulating ramA gene expression, resulting in the MDR phenotype. Our study also revealed a large number of cis-encoded antisense npcRNA candidates, supporting previous observations of global sense–antisense regulatory networks in bacteria. Finally, at least six of the npcRNA candidates interacted with the S. typhi Hfq protein, supporting an important role of Hfq in npcRNA networks. This study points to novel functional npcRNA candidates potentially involved in various regulatory roles including the pathogenicity of S. typhi. PMID:20460466

  13. EBV reactivation as a target of luteolin to repress NPC tumorigenesis

    PubMed Central

    Wu, Chung-Chun; Fang, Chih-Yeu; Hsu, Hui-Yu; Chuang, Hsin-Ying; Cheng, Yu-Jhen; Chen, Yen-Ju; Chou, Sheng-Ping; Huang, Sheng-Yen; Lin, Su-Fang; Chang, Yao; Tsai, Ching-Hwa; Chen, Jen-Yang

    2016-01-01

    Nasopharyngeal carcinoma (NPC) is a malignancy derived from the epithelial cells of the nasopharynx. Although a combination of radiotherapy with chemotherapy is effective for therapy, relapse and metastasis after remission remain major causes of mortality. Epstein-Barr virus (EBV) is believed to be one of causes of NPC development. We demonstrated previously that EBV reactivation is important for the carcinogenesis of NPC. We sought, therefore, to determine whether EBV reactivation can be a target for retardation of relapse of NPC. After screening, we found luteolin is able to inhibit EBV reactivation. It inhibited EBV lytic protein expression and repressed the promoter activities of two major immediate-early genes, Zta and Rta. Furthermore, luteolin was shown to reduce genomic instability induced by recurrent EBV reactivation in NPC cells. EBV reactivation-induced NPC cell proliferation and migration, as well as matrigel invasiveness, were also repressed by luteolin treatment. Tumorigenicity in mice, induced by EBV reactivation, was decreased profoundly following luteolin administration. Together, these results suggest that inhibition of EBV reactivation is a novel approach to prevent the relapse of NPC. PMID:26967558

  14. NREL Pyrheliometer Comparison: September 16 to 27, 2013 (NPC-2013)

    SciTech Connect

    Reda, I.; Dooraghi, M.; Habte, A.

    2013-11-01

    Accurate measurements of direct normal (beam) solar irradiance from pyrheliometers are important for the development and deployment of solar energy conversion systems, improving our understanding of the Earth's energy budget for climate change studies, and for other science and technology applications involving solar flux. Providing these measurements places many demands on the quality system used by the operator of commercially available radiometers. Maintaining accurate radiometer calibrations traceable to an international standard is the first step in producing research-quality solar irradiance measurements. As with all measurement systems, absolute cavity radiometers and other types of pyrheliometers are subject to performance changes over time. NREL has developed and maintained a group of absolute cavity radiometers with direct calibration traceability to the World Radiometric Reference (WRR). These reference instruments are used by NREL to calibrate pyrheliometers and pyranometers using the ISO 17025 accredited Broadband Outdoor Radiometer Calibration (BORCAL) process (Reda et al. 2008). NPCs are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owners/operators, e.g. NREL, NASA, NIST, NOAA, USA industry and academia, USA-DOE and other national laboratories, and national and international organizations. Each NPC provides an opportunity to determine the unique World Radiometric Reference (WRR) transfer factor (WRR-TF) for each participating pyrheliometer. By adjusting all subsequent pyrheliometer measurements by the appropriate WRR-TF, the solar irradiance data are traceable to the International System of Units through WRR.

  15. Understanding the interplay between host immunity and Epstein-Barr virus in NPC patients

    PubMed Central

    Shen, Yong; Zhang, Suzhan; Sun, Ren; Wu, Tingting; Qian, Jing

    2015-01-01

    Epstein-Barr virus (EBV) has been used as a paradigm for studying host–virus interactions, not only because of its importance as a human oncogenic virus associated with several malignancies including nasopharyngeal carcinoma (NPC) but also owing to its sophisticated strategies to subvert the host antiviral responses. An understanding of the interplay between EBV and NPC is critical for the development of EBV-targeted immunotherapy. Here, we summarize the current knowledge regarding the host immune responses and EBV immune evasion mechanisms in the context of NPC. PMID:26038769

  16. Switching Characteristics of Ferroelectric Transistor Inverters

    NASA Technical Reports Server (NTRS)

    Laws, Crystal; Mitchell, Coey; MacLeod, Todd C.; Ho, Fat D.

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  17. Integrated Inverter And Battery Charger

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.

    1988-01-01

    Circuit combines functions of dc-to-ac inversion (for driving ac motor in battery-powered vehicle) and ac-to-dc conversion (for charging battery from ac line when vehicle not in use). Automatically adapts to either mode. Design of integrated inverter/charger eliminates need for duplicate components, saves space, reduces weight and cost of vehicle. Advantages in other applications : load-leveling systems, standby ac power systems, and uninterruptible power supplies.

  18. NREL Pyrheliometer Comparisons (NPC-2001), September 24 - October 5, 2001, Golden, Colorado

    SciTech Connect

    Reda, I.; Stoffel, T.; Wilcox, S.

    2003-09-01

    NREL Pyrheliometer Comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owner/operators, the NPC provides an opportunity to determine the unique WRR transfer factor for each participating pyrheliometer.

  19. NREL Pyrheliometer Comparisons (NPC-2003), September 22 - October 3, 2003, Golden, Colorado

    SciTech Connect

    Stoffel, T.; Reda, I.; Wilcox, S.

    2004-07-01

    NREL Pyrheliometer Comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owner/operators, the NPC provides an opportunity to determine the unique WRR transfer factor for each participating pyrheliometer.

  20. Results of NREL Pyrheliometer Comparisons (NPC1999), October 4-10, 1999, Golden, Colorado

    SciTech Connect

    Reda, I.; Stoffel, T.; Wilcox, S.

    2000-09-01

    NREL Pyrheliometer Comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owner/operators, the NPC provides an opportunity to determine the unique WRR transfer factor for each participating pyrheliometer.

  1. NREL Pyrheliometer Comparisons (NPC-2002), September 23 - October 4, 2002, Golden, Colorado

    SciTech Connect

    Reda, I.; Stoffel, T.; Wilcox, S.

    2003-09-01

    NREL Pyrheliometer Comparisons (NPCs) are held annually at the Solar Radiation Research Laboratory (SRRL) in Golden, Colorado. Open to all pyrheliometer owner/operators, the NPC provides an opportunity to determine the unique WRR transfer factor for each participating pyrheliometer.

  2. Stepped sinewave inverter

    NASA Astrophysics Data System (ADS)

    Appelbaum, J.; Gabbay, D.

    1984-11-01

    A stepped sinewave dc/ac inverter was analyzed for an inductive load with respect to load current and voltage, harmonics, power factor, and efficiency. This special inverter of high efficiency and low harmonic content is constructed by synthesizing the sinusoidal output by discrete voltage sources, such as storage batteries, solar cell, etc., with electronic switching of the sources at specific time intervals. The switching times are determined for the condition of minimum distortion of the synthesized wave. A 50 W inverter was built and tested to demonstrate this approach.

  3. Subversion of NPC1 pathway of cholesterol transport by Anaplasma phagocytophilum

    PubMed Central

    Xiong, Qingming; Rikihisa, Yasuko

    2013-01-01

    Summary Intracellular cholesterol amounts, distribution, and traffic are tightly regulated to maintain the healthy eukaryotic cell function. However, how intracellular pathogens that require cholesterol, interact with the host cholesterol homeostasis and traffic is not well understood. Anaplasma phagocytophilum is an obligatory intracellular and cholesterol-robbing bacterium, which causes human granulocytic anaplasmosis. Here we found that a subset of cholesterol-binding membrane protein, Niemann–Pick type C1 (NPC1)-bearing vesicles devoid of lysosomal markers were upregulated in HL-60 cells infected with A. phagocytophilum, and trafficked to live bacterial inclusions. The NPC1 localization to A. phagocytophilum inclusions was abolished by low-density lipoprotein (LDL)-derived cholesterol traffic inhibitor U18666A. Studies using NPC1 siRNA and the cell line with cholesterol traffic defect demonstrated that the NPC1 function is required for bacterial cholesterol acquisition and infection. Furthermore, trans-Golgi network-specific soluble N-ethylmaleimide-sensitive factor attachment protein receptors, vesicle-associated membrane protein (VAMP4) and syntaxin 16, which are associated with NPC1 and LDL-derived cholesterol vesicular transport were recruited to A. phagocytophilum inclusions, and VAMP4 was required for bacteria infection. Taken together, A. phagocytophilum is the first example of a pathogen that subverts the NPC1 pathway of intracellular cholesterol transport and homeostasis for bacterial inclusion membrane biogenesis and cholesterol capture. PMID:22212234

  4. Inhibiting intestinal NPC1L1 activity prevents diet-induced increase in biliary cholesterol in Golden Syrian hamsters.

    PubMed

    Valasek, Mark A; Repa, Joyce J; Quan, Gang; Dietschy, John M; Turley, Stephen D

    2008-10-01

    Niemann-Pick C1-like 1 (NPC1L1) facilitates the uptake of sterols into the enterocyte and is the target of the novel cholesterol absorption inhibitor, ezetimibe. These studies used the Golden Syrian hamster as a model to delineate the changes in the relative mRNA expression of NPC1L1 and other proteins that regulate sterol homeostasis in the enterocyte during and following cessation of ezetimibe treatment and also to address the clinically important question of whether the marked inhibition of cholesterol absorption alters biliary lipid composition. In hamsters fed a low-cholesterol, low-fat basal diet, the abundance of mRNA for NPC1L1 in the small intestine far exceeded that in other regions of the gastrointestinal tract, liver, and gallbladder. In the first study, female hamsters were fed the basal diet containing ezetimibe at doses up to 2.0 mg.day(-1).kg body wt(-1). At this dose, cholesterol absorption fell by 82%, fecal neutral sterol excretion increased by 5.3-fold, and hepatic and intestinal cholesterol synthesis increased more than twofold, but there were no significant changes in either fecal bile acid excretion or biliary lipid composition. The ezetimibe-induced changes in intestinal cholesterol handling were reversed when treatment was withdrawn. In a second study, male hamsters were given a diet enriched in cholesterol and safflower oil without or with ezetimibe. The lipid-rich diet raised the absolute and relative cholesterol levels in bile more than fourfold. This increase was largely prevented by ezetimibe. These data are consistent with the recent finding that ezetimibe treatment significantly reduced biliary cholesterol saturation in patients with gallstones. PMID:18718997

  5. Reliable inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  6. Adenovirus RIDα uncovers a novel pathway requiring ORP1L for lipid droplet formation independent of NPC1

    PubMed Central

    Cianciola, Nicholas L.; Greene, Diane J.; Morton, Richard E.; Carlin, Cathleen R.

    2013-01-01

    Niemann–Pick disease type C (NPC) is caused by mutations in NPC1 or NPC2, which coordinate egress of low-density-lipoprotein (LDL)-cholesterol from late endosomes. We previously reported that the adenovirus-encoded protein RIDα rescues the cholesterol storage phenotype in NPC1-mutant fibroblasts. We show here that RIDα reconstitutes deficient endosome-to-endoplasmic reticulum (ER) transport, allowing excess LDL-cholesterol to be esterified by acyl-CoA:cholesterol acyltransferase and stored in lipid droplets (LDs) in NPC1-deficient cells. Furthermore, the RIDα pathway is regulated by the oxysterol-binding protein ORP1L. Studies have classified ORP1L as a sterol sensor involved in LE positioning downstream of GTP-Rab7. Our data, however, suggest that ORP1L may play a role in transport of LDL-cholesterol to a specific ER pool designated for LD formation. In contrast to NPC1, which is dispensable, the RIDα/ORP1L-dependent route requires functional NPC2. Although NPC1/NPC2 constitutes the major pathway, therapies that amplify minor egress routes for LDL-cholesterol could significantly improve clinical management of patients with loss-of-function NPC1 mutations. The molecular identity of putative alternative pathways, however, is poorly characterized. We propose RIDα as a model system for understanding physiological egress routes that use ORP1L to activate ER feedback responses involved in LD formation. PMID:24025716

  7. Characterisation of two deletions involving NPC1 and flanking genes in Niemann-Pick type C disease patients.

    PubMed

    Rodríguez-Pascau, Laura; Toma, Claudio; Macías-Vidal, Judit; Cozar, Mónica; Cormand, Bru; Lykopoulou, Lilia; Coll, Maria Josep; Grinberg, Daniel; Vilageliu, Lluïsa

    2012-12-01

    Niemann-Pick type C (NPC) disease is an autosomal recessive lysosomal disorder characterised by the accumulation of a complex pattern of lipids in the lysosomal-late endosomal system. More than 300 disease-causing mutations have been identified so far in the NPC1 and NPC2 genes, including indel, missense, nonsense and splicing mutations. Only one genomic deletion, of more than 23 kb, has been previously reported. We describe two larger structural variants, encompassing NPC1 and flanking genes, as a cause of the disease. QMPSF, SNP inheritance and CytoScan® HD Array were used to confirm and further characterise the presence of hemizygous deletions in two patients. One of the patients (NPC-57) bore a previously described missense mutation (p.T1066N) and an inherited deletion that included NPC1, C18orf8 and part of ANKRD29 gene. The second patient (NPC-G1) had a 1-bp deletion (c.852delT; p.F284Lfs*26) and a deletion encompassing the promoter region and exons 1-10 of NPC1 and the adjacent ANKRD29 and LAMA3. This study characterised two novel chromosomal microdeletions at 18q11-q12 that cause NPC disease and provide insight into missing NPC1 mutant alleles. PMID:23142039

  8. Novel multilevel inverter carrier-based PWM method

    SciTech Connect

    Tolbert, L.M.; Habetler, T.G.

    1999-10-01

    The advent of the transformerless multilevel inverter topology has brought forth various pulsewidth modulation (PWM) schemes as a means to control the switching of the active devices in each of the multiple voltage levels in the inverter. An analysis of how existing multilevel carrier-based PWM affects switch utilization for the different levels of a diode-clamped inverter is conducted. Two novel carrier-based multilevel PWM schemes are presented which help to optimize or balance the switch utilization in multilevel inverters. A 10-kW prototype six-level diode-clamped inverter has been built and controlled with the novel PWM strategies proposed in this paper to act as a voltage-source inverter for a motor drive.

  9. Filovirus receptor NPC1 contributes to species-specific patterns of ebolavirus susceptibility in bats

    PubMed Central

    Ng, Melinda; Ndungo, Esther; Kaczmarek, Maria E; Herbert, Andrew S; Binger, Tabea; Kuehne, Ana I; Jangra, Rohit K; Hawkins, John A; Gifford, Robert J; Biswas, Rohan; Demogines, Ann; James, Rebekah M; Yu, Meng; Brummelkamp, Thijn R; Drosten, Christian; Wang, Lin-Fa; Kuhn, Jens H; Müller, Marcel A; Dye, John M; Sawyer, Sara L; Chandran, Kartik

    2015-01-01

    Biological factors that influence the host range and spillover of Ebola virus (EBOV) and other filoviruses remain enigmatic. While filoviruses infect diverse mammalian cell lines, we report that cells from African straw-colored fruit bats (Eidolon helvum) are refractory to EBOV infection. This could be explained by a single amino acid change in the filovirus receptor, NPC1, which greatly reduces the affinity of EBOV-NPC1 interaction. We found signatures of positive selection in bat NPC1 concentrated at the virus-receptor interface, with the strongest signal at the same residue that controls EBOV infection in Eidolon helvum cells. Our work identifies NPC1 as a genetic determinant of filovirus susceptibility in bats, and suggests that some NPC1 variations reflect host adaptations to reduce filovirus replication and virulence. A single viral mutation afforded escape from receptor control, revealing a pathway for compensatory viral evolution and a potential avenue for expansion of filovirus host range in nature. DOI: http://dx.doi.org/10.7554/eLife.11785.001 PMID:26698106

  10. Photodynamic effects on nasopharyngeal carcinoma (NPC) cells with 5-aminolevulinic acid or its hexyl ester.

    PubMed

    Wu, R W K; Chu, E S M; Yow, C M N; Chen, J Y

    2006-10-01

    Nasopharyngeal carcinoma (NPC) is a prevalent cancer in Hong Kong and southern China. To explore a new modality of NPC treatment, 5-aminolevulinic acid (ALA) or its hexyl ester (ALA-H) mediated photodynamic therapy (PDT) was studied in vitro. The results show that NPC cells are sensitive to both ALA and ALA-H mediated PDT. However, ALA-H PDT is much more effective at cell inactivation than ALA-PDT, due to a higher efficiency of ALA-H on producing endogenous protoporphyrin (PpIX) in cells. Both apoptosis and necrosis are involved in cell death, but apoptosis plays a major role under the short time incubation of drugs. ALA and ALA-H mediated PDT not only destroy the cells directly, but also inhibit the expression of matrix metalloproteinase-2 (MMP2) in cells, a maker for tumor metastasis. The ALA-H shows promising PDT results on NPC in vitro; therefore it is worth investigating further in vivo for NPC treatment. PMID:16442708

  11. Resonant snubber inverter

    DOEpatents

    Lai, J.S.; Young, R.W. Sr.; Chen, D.; Scudiere, M.B.; Ott, G.W. Jr.; White, C.P.; McKeever, J.W.

    1997-06-24

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter. 14 figs.

  12. Resonant snubber inverter

    DOEpatents

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  13. Ebola Virus and Severe Acute Respiratory Syndrome Coronavirus Display Late Cell Entry Kinetics: Evidence that Transport to NPC1+ Endolysosomes Is a Rate-Defining Step

    PubMed Central

    Mingo, Rebecca M.; Simmons, James A.; Shoemaker, Charles J.; Nelson, Elizabeth A.; Schornberg, Kathryn L.; D'Souza, Ryan S.; Casanova, James E.

    2014-01-01

    occurred in West Africa in 2014, and there was a significant outbreak of SARS in 2003. No effective vaccine or treatment has yet been approved for either virus. We present evidence that both viruses traffic late into the endocytic pathway, to NPC1+ LE/Lys, in order to enter host cells, and that they do so to access high levels of cathepsin activity, which both viruses use in their fusion-triggering mechanisms. This unexpected similarity suggests an unexplored vulnerability, trafficking to NPC1+ LE/Lys, as a therapeutic target for SARS and EBOV. PMID:25552710

  14. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2002-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  15. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    1997-01-01

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  16. Multilevel cascade voltage source inverter with separate DC sources

    DOEpatents

    Peng, F.Z.; Lai, J.S.

    1997-06-24

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

  17. Multilevel cascade voltage source inverter with seperate DC sources

    DOEpatents

    Peng, Fang Zheng; Lai, Jih-Sheng

    2001-04-03

    A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

  18. Structural Insights into the Niemann-Pick C1 (NPC1)-Mediated Cholesterol Transfer and Ebola Infection.

    PubMed

    Gong, Xin; Qian, Hongwu; Zhou, Xinhui; Wu, Jianping; Wan, Tao; Cao, Pingping; Huang, Weiyun; Zhao, Xin; Wang, Xudong; Wang, Peiyi; Shi, Yi; Gao, George F; Zhou, Qiang; Yan, Nieng

    2016-06-01

    Niemann-Pick disease type C (NPC) is associated with mutations in NPC1 and NPC2, whose gene products are key players in the endosomal/lysosomal egress of low-density lipoprotein-derived cholesterol. NPC1 is also the intracellular receptor for Ebola virus (EBOV). Here, we present a 4.4 Å structure of full-length human NPC1 and a low-resolution reconstruction of NPC1 in complex with the cleaved glycoprotein (GPcl) of EBOV, both determined by single-particle electron cryomicroscopy. NPC1 contains 13 transmembrane segments (TMs) and three distinct lumenal domains A (also designated NTD), C, and I. TMs 2-13 exhibit a typical resistance-nodulation-cell division fold, among which TMs 3-7 constitute the sterol-sensing domain conserved in several proteins involved in cholesterol metabolism and signaling. A trimeric EBOV-GPcl binds to one NPC1 monomer through the domain C. Our structural and biochemical characterizations provide an important framework for mechanistic understanding of NPC1-mediated intracellular cholesterol trafficking and Ebola virus infection. PMID:27238017

  19. All-trans retinoic acid triggered antimicrobial activity against Mycobacterium tuberculosis is dependent on NPC2

    PubMed Central

    Inkeles, Megan S.; De Leon, Avelino; Pellegrini, Matteo; Krutzik, Stephan R.; Liu, Philip T.

    2014-01-01

    A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the mechanism is unclear. Here, we demonstrate that vitamin A-triggered antimicrobial activity against M. tuberculosis requires expression of Niemann-Pick disease type C2 (NPC2). Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3 (1,25D3), the biologically active forms of vitamin A and vitamin D, respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Stimulation of primary human monocytes with ATRA did not result in expression of the antimicrobial peptide cathelicidin, which is required for 1,25D3 antimicrobial activity. In contrast, ATRA triggers a reduction in the total cellular cholesterol concentration, whereas 1,25D3 did not. Blocking ATRA-induced cellular cholesterol reduction inhibits antimicrobial activity as well. Bioinformatic analysis of ATRA and 1,25D3 induced gene profiles suggests Niemann-Pick disease type C2 (NPC2) is a key gene in ATRA-induced cholesterol regulation. Knockdown experiments demonstrate that ATRA-mediated decrease of total cellular cholesterol content and increase in lysosomal acidification are both dependent upon expression of NPC2. Expression of NPC2 was lower in caseous tuberculosis granulomas and M. tuberculosis-infected monocytes compared to normal lung and uninfected cells, respectively. Loss of NPC2 expression ablated ATRA-induced antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated antimicrobial mechanism against M. tuberculosis requires NPC2-dependent expression and function, indicating a key role for cellular cholesterol regulation in the innate immune response. PMID:24501203

  20. Inverting the Achievement Pyramid

    ERIC Educational Resources Information Center

    White-Hood, Marian; Shindel, Melissa

    2006-01-01

    Attempting to invert the pyramid to improve student achievement and increase all students' chances for success is not a new endeavor. For decades, educators have strategized, formed think tanks, and developed school improvement teams to find better ways to improve the achievement of all students. Currently, the No Child Left Behind Act (NCLB) is…

  1. Energy-Saving Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  2. Program Predicts Nonlinear Inverter Performance

    NASA Technical Reports Server (NTRS)

    Al-Ayoubi, R. R.; Oepomo, T. S.

    1985-01-01

    Program developed for ac power distribution system on Shuttle orbiter predicts total load on inverters and node voltages at each of line replaceable units (LRU's). Mathematical model simulates inverter performance at each change of state in power distribution system.

  3. Structural Basis of Sterol Binding by NPC2, a Lysosomal Protein Deficient in Niemann-Pick Type C2 Disease

    SciTech Connect

    Xu,S.; Benoff, B.; Liou, H.; Lobel, P.; Stock, A.

    2007-01-01

    NPC2 is a small lysosomal glycoprotein that binds cholesterol with submicromolar affinity. Deficiency in NPC2 is the cause of Niemann-Pick type C2 disease, a fatal neurovisceral disorder characterized by accumulation of cholesterol in lysosomes. Here we report the crystal structure of bovine NPC2 bound to cholesterol-3-O-sulfate, an analog that binds with greater apparent affinity than cholesterol. Structures of both apo-bound and sterol-bound NPC2 were observed within the same crystal lattice, with an asymmetric unit containing one molecule of apoNPC2 and two molecules of sterol-bound NPC2. As predicted from a previously determined structure of apoNPC2, the sterol binds in a deep hydrophobic pocket sandwiched between the two {beta}-sheets of NPC2, with only the sulfate substituent of the ligand exposed to solvent. In the two available structures of apoNPC2, the incipient ligand-binding pocket, which ranges from a loosely packed hydrophobic core to a small tunnel, is too small to accommodate cholesterol. In the presence of sterol, the pocket expands, facilitated by a slight separation of the {beta}-strands and substantial reorientation of some side chains, resulting in a perfect molding of the pocket around the hydrocarbon portion of cholesterol. A notable feature is the repositioning of two aromatic residues at the tunnel entrance that are essential for NPC2 function. The NPC2 structures provide evidence of a malleable binding site, consistent with the previously documented broad range of sterol ligand specificity.

  4. Loss of NPC1 function in a patient with a co-inherited novel insulin receptor mutation does not grossly modify the severity of the associated insulin resistance.

    PubMed

    Kirk, J; Porter, K M; Parker, V; Barroso, I; O'Rahilly, S; Hendriksz, C; Semple, R K

    2010-12-01

    In Npc1 null mice, a model for Niemann Pick Disease Type C1, it has been reported that hepatocyte insulin receptor function is significantly impaired, consistent with growing evidence that membrane fluidity and microdomain structure have an important role in insulin signal transduction. However, whether insulin receptor function is also compromised in human Niemann Pick disease Type C1 is unclear. We now report a girl who developed progressive dementia, ataxia and opthalmoplegia from 9 years old, followed by severe acanthosis nigricans, hirsutism and acne at 11 years old. She was diagnosed with Niemann Pick Disease type C1 (OMIM#257220) based on positive filipin staining and reduced cholesterol-esterifying activity in dermal fibroblasts, and homozygosity for the p.Ile1061Thr NPC1 mutation. Further analysis revealed her also to be heterozygous for a novel trinucleotide deletion (c.3659 + 1_3659 + 3delGTG) at the end of exon 20 of INSR, encoding the insulin receptor, leading to deletion of Trp1193 in the intracellular tyrosine kinase domain. INSR mRNA and protein levels were normal in dermal fibroblasts, consistent with a primary signal transduction defect in the mutant receptor. Although the proband was significantly more insulin resistant than her father, who carried the INSR mutation but was only heterozygous for the NPC1 variant, their respective degrees of IR were very similar to those previously reported in a father-daughter pair with the closely related p.Trp1193Leu INSR mutation. This suggests that loss of NPC1 function, with attendant changes in membrane cholesterol composition, does not significantly modify the IR phenotype, even in the context of severely impaired INSR function. PMID:20521171

  5. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Osullivan, G.; Merrill, W. C.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. Optimization of the inverter/controller design is discussed as part of an overall photovoltaic power system designed for maximum energy extraction from the solar array. The special design requirements for the inverter/ controller include: a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy.

  6. HNF1α and SREBP2 are important regulators of NPC1L1 in human liver

    PubMed Central

    Pramfalk, Camilla; Jiang, Zhao-Yan; Cai, Qu; Hu, Hai; Zhang, Sheng-Dao; Han, Tian-Quan; Eriksson, Mats; Parini, Paolo

    2010-01-01

    Niemann-Pick C1-like 1 (NPC1L1), a key regulator of intestinal cholesterol absorption, is highly expressed in human liver. Here, we aimed to gain more insight into mechanisms participating in its hepatic regulation in humans. Correlation analysis in livers from Chinese patients with and without gallstone disease revealed strong positive correlations between NPC1L1 and sterol regulatory element binding protein 2 (SREBP2) (r = 0.74, P < 0.05) and between NPC1L1 and hepatic nuclear factor α (HNF4α) (r = 0.53, P < 0.05) mRNA expression. HNF4α is an upstream regulator of HNF1α; thus, we also tested whether HNF1α participates in the regulation of NPC1L1. We showed a dose-dependent regulation by SREBP2 on the NPC1L1 promoter activity and mRNA expression in HuH7 cells. Chromatin immunoprecipitation assay confirmed the binding of SREBP2 to the promoter in vivo. Surprisingly, HNF4α slightly decreased the NPC1L1 promoter activity but had no effect on its gene expression. By contrast, HNF1α increased the promoter activity and the gene expression, and an important HNF1 binding site was identified within the human NPC1L1 promoter. ChIP assays confirmed that HNF1α can bind to the NPC1L1 promoter in vivo. PMID:20460578

  7. Cholesterol accumulation in Niemann Pick type C (NPC) model cells causes a shift in APP localization to lipid rafts

    SciTech Connect

    Kosicek, Marko; Malnar, Martina; Goate, Alison; Hecimovic, Silva

    2010-03-12

    It has been suggested that cholesterol may modulate amyloid-{beta} (A{beta}) formation, a causative factor of Alzheimer's disease (AD), by regulating distribution of the three key proteins in the pathogenesis of AD ({beta}-amyloid precursor protein (APP), {beta}-secretase (BACE1) and/or presenilin 1 (PS1)) within lipid rafts. In this work we tested whether cholesterol accumulation upon NPC1 dysfunction, which causes Niemann Pick type C disease (NPC), causes increased partitioning of APP into lipid rafts leading to increased CTF/A{beta} formation in these cholesterol-rich membrane microdomains. To test this we used CHO NPC1{sup -/-} cells (NPC cells) and parental CHOwt cells. By sucrose density gradient centrifugation we observed a shift in fl-APP/CTF compartmentalization into lipid raft fractions upon cholesterol accumulation in NPC vs. wt cells. Furthermore, {gamma}-secretase inhibitor treatment significantly increased fl-APP/CTF distribution in raft fractions in NPC vs. wt cells, suggesting that upon cholesterol accumulation in NPC1-null cells increased formation of APP-CTF and its increased processing towards A{beta} occurs in lipid rafts. Our results support that cholesterol overload, such as in NPC disease, leads to increased partitioning of APP/CTF into lipid rafts resulting in increased amyloidogenic processing of APP in these cholesterol-rich membranes. This work adds to the mechanism of the cholesterol-effect on APP processing and the pathogenesis of Alzheimer's disease and supports the role of lipid rafts in these processes.

  8. National Renewable Energy Laboratory Pyrheliometer Comparisons: 24 September - 5 October 2012 (NPC-2012)

    SciTech Connect

    Stoffel, T.; Reda, I.

    2013-05-01

    The NREL Pyrheliometer Comparisons for 2012 (NPC-2012) were held at the Solar Radiation Research Laboratory in Golden, Colorado, from September 24 through October 5 for the purpose of transferring the World Radiometric Reference (WRR) to participating instrument. Twenty scientists and engineers operated 32 absolute cavity radiometers and 18 conventional thermopile-based pyrheliometers to simultaneously measure clear-sky direct normal irradiance during the comparisons. The transfer standard group of reference radiometers for NPC-2012 consisted of four NREL radiometers with direct traceability to the WRR, having participated in the Eleventh International Pyrheliometer Comparisons (IPC-XI) hosted by the World Radiation Center in the fall of 2010. As the result of NPC-2012, each participating absolute cavity radiometer was assigned a new WRR transfer factor, computed as the reference irradiance computed by the transfer standard group divided by the observed irradiance from the participating radiometer. The performance of the transfer standard group during NPC-2012 was consistent with previous comparisons, including IPC-XI. The measurement performance of the transfer standard group allowed the transfer of the WRR to each participating radiometer with an estimated uncertainty of +/- 0.33% with respect to the International System of Units.

  9. Acid sphingomyelinase activity is regulated by membrane lipids and facilitates cholesterol transfer by NPC2[S

    PubMed Central

    Oninla, Vincent O.; Breiden, Bernadette; Babalola, Jonathan O.; Sandhoff, Konrad

    2014-01-01

    During endocytosis, membrane components move to intraluminal vesicles of the endolysosomal compartment for digestion. At the late endosomes, cholesterol is sorted out mainly by two sterol-binding proteins, Niemann-Pick protein type C (NPC)1 and NPC2. To study the NPC2-mediated intervesicular cholesterol transfer, we developed a liposomal assay system. (Abdul-Hammed, M., B. Breiden, M. A. Adebayo, J. O. Babalola, G. Schwarzmann, and K. Sandhoff. 2010. Role of endosomal membrane lipids and NPC2 in cholesterol transfer and membrane fusion. J. Lipid Res. 51: 1747–1760.) Anionic lipids stimulate cholesterol transfer between liposomes while SM inhibits it, even in the presence of anionic bis(monoacylglycero)phosphate (BMP). Preincubation of vesicles containing SM with acid sphingomyelinase (ASM) (SM phosphodiesterase, EC 3.1.4.12) results in hydrolysis of SM to ceramide (Cer), which enhances cholesterol transfer. Besides SM, ASM also cleaves liposomal phosphatidylcholine. Anionic phospholipids derived from the plasma membrane (phosphatidylglycerol and phosphatidic acid) stimulate SM and phosphatidylcholine hydrolysis by ASM more effectively than BMP, which is generated during endocytosis. ASM-mediated hydrolysis of liposomal SM was also stimulated by incorporation of diacylglycerol (DAG), Cer, and free fatty acids into the liposomal membranes. Conversely, phosphatidylcholine hydrolysis was inhibited by incorporation of cholesterol, Cer, DAG, monoacylglycerol, and fatty acids. Our data suggest that SM degradation by ASM is required for physiological secretion of cholesterol from the late endosomal compartment, and is a key regulator of endolysosomal lipid digestion. PMID:25339683

  10. Inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  11. Inverted organic photovoltaic cells.

    PubMed

    Wang, Kai; Liu, Chang; Meng, Tianyu; Yi, Chao; Gong, Xiong

    2016-05-21

    The advance in lifestyle, modern industrialization and future technological revolution are always at high expense of energy consumption. Unfortunately, there exist serious issues such as limited storage, high cost and toxic contamination in conventional fossil fuel energy sources. Instead, solar energy represents a renewable, economic and green alternative in the future energy market. Among the photovoltaic technologies, organic photovoltaics (OPVs) demonstrate a cheap, flexible, clean and easy-processing way to convert solar energy into electricity. However, OPVs with a conventional device structure are still far away from industrialization mainly because of their short lifetime and the energy-intensive deposition of top metal electrode. To address the stability and cost issue simultaneously, an inverted device structure has been introduced into OPVs, bridging laboratory research with practical application. In this review, recent progress in device structures, working mechanisms, functions and advances of each component layer as well their correlations with the efficiency and stability of inverted OPVs are reviewed and illustrated. PMID:27087582

  12. Inverted organic photosensitive device

    SciTech Connect

    Forrest, Stephen R.; Tong, Xiaoran; Lee, Jun Yeob; Cho, Yong Joo

    2015-09-08

    There is disclosed a method for preparing the surface of a metal substrate. The present disclosure also relates to an organic photovoltaic device including a metal substrate made by such method. Also disclosed herein is an inverted photosensitive device including a stainless steel foil reflective electrode, an organic donor-acceptor heterojunction over the reflective electrode, and a transparent electrode over the donor-acceptor heterojunction.

  13. Sterol transfer between cyclodextrin and membranes: similar but not identical mechanism to NPC2-mediated cholesterol transfer.

    PubMed

    McCauliff, Leslie A; Xu, Zhi; Storch, Judith

    2011-08-30

    Niemann--Pick C disease is an inherited disorder in which cholesterol and other lipids accumulate in the late endosomal/lysosomal compartment. Recently, cyclodextrins (CD) have been shown to reduce symptoms and extend lifespan in animal models of the disease. In the present studies we examined the mechanism of sterol transport by CD using in vitro model systems and fluorescence spectroscopy and NPC2-deficient fibroblasts. We demonstrate that cholesterol transport from the lysosomal cholesterol-binding protein NPC2 to CD occurs via aqueous diffusional transfer and is very slow; the rate-limiting step appears to be dissociation of cholesterol from NPC2, suggesting that specific interactions between NPC2 and CD do not occur. In contrast, the transfer rate of the fluorescent cholesterol analogue dehydroergosterol (DHE) from CD to phospholipid membranes is very rapid and is directly proportional to the acceptor membrane concentration, as is DHE transfer from membranes to CD. Moreover, CD dramatically increases the rate of sterol transfer between membranes, with rates that can approach those mediated by NPC2. The results suggest that sterol transfer from CD to membranes occurs by a collisional transfer mechanism involving direct interaction of CD with membranes, similar to that shown previously for NPC2. For CD, however, absolute rates are slower compared to NPC2 for a given concentration, and the lysosomal phospholipid lysobisphosphatidic acid (LBPA) does not stimulate rates of sterol transfer between membranes and CD. As expected from the apparent absence of interaction between CD and NPC2, the addition of CD to NPC2-deficient fibroblasts rapidly rescued the cholesterol accumulation phenotype. Thus, the recent observations of CD efficacy in mouse models of NPC disease are likely the result of CD enhancement of cholesterol transport between membranes, with rapid sterol transfer occurring during CD--membrane interactions. PMID:21740003

  14. Antinociceptive profile of the pseudopeptide B2 bradykinin receptor antagonist NPC 18688 in mice.

    PubMed Central

    Corrêa, C. R.; Kyle, D. J.; Chakraverty, S.; Calixto, J. B.

    1996-01-01

    1. The purpose of this study was to investigate the topical and systemic anti-hyperalgesic effect of the newly-developed pseudopeptide B2 receptor antagonist, NPC 18688, in different models of nociception in mice. 2. Given systemically 30 min beforehand, NPC 18688 (10-300 nmol kg-1, i.p.) caused no agonist effect, but produced a dose-related and significant inhibition of abdominal constrictions caused by intraperitoneal injection of acetic acid (0.6%), acetylcholine (ACh, 4.5 mg kg-1) or kaolin (50 mg kg-1). The calculated mean ID50s and the percentages of maximal inhibitions (MI) for these effects were: 77, 34 and > 300 nmol kg-1 and 65 +/- 6, 70 +/- 5 and 40 +/- 3%, respectively. The anti-hyperalgesic effect of NPC 18688 (100 nmol kg-1, i.p.) occurred rapidly (30 min) and lasted for at least 150 min. Hoe 140 (3-30 nmol kg-1, i.p.) given 30 min beforehand also inhibited, in a graded manner, acetic acid and ACh-induced writhing, with mean ID50s and MI of 6 and 9 nmol kg-1 and 56 +/- 7 and 62 +/- 6%, respectively. 3. NPC 18688 (10-300 nmol kg-1, i.p.) caused a graded inhibition of both phases of formalin (2.5%)-induced pain, its effects being more potent in relation to the second phase of the formalin test. The calculated mean ID50s and the MI were > 300 and 60 nmol kg-1 and 20 +/- 3 and 60 +/- 5% against the first and second phases of formalin-induced nociception, respectively. NPC 18688 at the same doses also inhibited, in a dose-related manner, formalin-induced paw oedema (MI of 35 +/- 3%). 4. When injected locally in the mouse paw, NPC 18688 (2, 10 and 20 nmol/paw) had no agonist activity. However, when co-injected with formalin NPC 18688 (2-20 nmol/paw), it produced significant inhibition of both phases of formalin response, with MI of 40 +/- 3 and 33 +/- 2%, respectively. NPC 18688 at 10 nmol/paw also significantly inhibited formalin-induced paw oedema (25 +/- 2%). 5. Given intraperitoneally, NPC 18688 (30-300 nmol kg-1) determined a graded inhibition of the

  15. Integral inverter/battery charger for use in electric vehicles

    NASA Technical Reports Server (NTRS)

    Thimmesch, D.

    1983-01-01

    The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

  16. The implementation in-house dose verification for IMRT and VMAT on breast cancer and NPC cases

    NASA Astrophysics Data System (ADS)

    Azzi, A.; Dimitri, F. Y.; Pawiro, S. A.

    2016-03-01

    IMRT and VMAT have been widely implemented on breast cancer and NPC cases. Dose verification was conducted to ensure the comparison between dose delivered and prescribe dose in TPS to obtain optimal results and the dose delivered. The gafchromic films measurement was done for breast and NPC simulation on RANDO Phantom, irradiating film by 6 MV photon with 200 cGy and scanned with EPSON V700 using 72 dpi. Dose distribution was calculated using the MATLAB-based in-house algorithm. In order to evaluate the gamma index, gafchromic films and MatriXX 2D array were placed in the Multi Cube and irradiated with EPID in same position. Dose distribution differences for IMRT and VMAT with modalities to TPS on film was 5.34% and 6.68% for NPC PTV70; 12.81% and 6.15% for NPC PTV50; 11.14% and 10.80% for breast cancer. Gamma index differences on IMRT with modalities to MatriXX 2D array and EPID was -0.09% and 5.13% for NPC; 0.51% and 2.28% for breast cancer. On the other hand, gamma index difference on VMAT was -1.65% and 1.43% for NPC; 0.19% and 4.38% for breast cancer. This measurement method can be used to verify dose for breast cancer and NPC cases in IMRT and VMAT.

  17. Inverted glass harp.

    PubMed

    Quinn, Daniel B; Rosenberg, Brian J

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions. PMID:26382336

  18. Inverted glass harp

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel B.; Rosenberg, Brian J.

    2015-08-01

    We present an analytical treatment of the acoustics of liquid-filled wine glasses, or "glass harps." The solution is generalized such that under certain assumptions it reduces to previous glass harp models, but also leads to a proposed musical instrument, the "inverted glass harp," in which an empty glass is submerged in a liquid-filled basin. The versatility of the solution demonstrates that all glass harps are governed by a family of solutions to Laplace's equation around a vibrating disk. Tonal analyses of recordings for a sample glass are offered as confirmation of the scaling predictions.

  19. A multilevel voltage-source inverter with separate dc sources for static var generation

    SciTech Connect

    Peng, Fang Zheng |; Lai, Jih-Sheng; McKeever, J.; VanCoevering, J.

    1995-09-01

    A new multilevel voltage-source inverter with a separate dc sources is proposed for high-voltage, high-power applications, such as flexible ac transmission systems (FACTS) including static var generation (SVG), power line conditioning, series compensation, phase shifting, voltage balancing, fuel cell and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the problems of conventional transformer-based multipulse inverters and the problems of the multilevel diode-clamped inverter and the multilevel flying capacitor inverter. To demonstrate the superiority of the new inverter, a SVG system using the new inverter topology is discussed through analysis, simulation and experiment.

  20. Gas cooled traction drive inverter

    SciTech Connect

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  1. Gas cooled traction drive inverter

    DOEpatents

    Chinthavali, Madhu Sudhan

    2016-04-19

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  2. Inverter Modeling For Accurate Energy Predictions Of Tracking HCPV Installations

    NASA Astrophysics Data System (ADS)

    Bowman, J.; Jensen, S.; McDonald, Mark

    2010-10-01

    High efficiency high concentration photovoltaic (HCPV) solar plants of megawatt scale are now operational, and opportunities for expanded adoption are plentiful. However, effective bidding for sites requires reliable prediction of energy production. HCPV module nameplate power is rated for specific test conditions; however, instantaneous HCPV power varies due to site specific irradiance and operating temperature, and is degraded by soiling, protective stowing, shading, and electrical connectivity. These factors interact with the selection of equipment typically supplied by third parties, e.g., wire gauge and inverters. We describe a time sequence model accurately accounting for these effects that predicts annual energy production, with specific reference to the impact of the inverter on energy output and interactions between system-level design decisions and the inverter. We will also show two examples, based on an actual field design, of inverter efficiency calculations and the interaction between string arrangements and inverter selection.

  3. Alternative algebras admitting derivations with invertible values and invertible derivations

    NASA Astrophysics Data System (ADS)

    Kaygorodov, I. B.; Popov, Yu S.

    2014-10-01

    We prove an analogue of the Bergen-Herstein-Lanski theorem for alternative algebras: describe all alternative algebras that admit derivations with invertible values. We also prove an analogue of Moens' theorem for alternative algebras (a finite-dimensional alternative algebra over a field of characteristic zero is nilpotent if and only if it admits an invertible Leibniz derivation).

  4. Miglustat Reverts the Impairment of Synaptic Plasticity in a Mouse Model of NPC Disease

    PubMed Central

    D'Arcangelo, G.; Grossi, D.; Racaniello, M.; Cardinale, A.; Zaratti, A.; Rufini, S.; Cutarelli, A.; Tancredi, V.; Merlo, D.; Frank, C.

    2016-01-01

    Niemann-Pick type C disease is an autosomal recessive storage disorder, characterized by abnormal sequestration of unesterified cholesterol within the late endolysosomal compartment of cells and accumulation of gangliosides and other sphingolipids. Progressive neurological deterioration and insurgence of symptoms like ataxia, seizure, and cognitive decline until severe dementia are pathognomonic features of the disease. Here, we studied synaptic plasticity phenomena and evaluated ERKs activation in the hippocampus of BALB/c NPC1−/− mice, a well described animal model of the disease. Our results demonstrated an impairment of both induction and maintenance of long term synaptic potentiation in NPC1−/− mouse slices, associated with the lack of ERKs phosphorylation. We then investigated the effects of Miglustat, a recent approved drug for the treatment of NPCD. We found that in vivo Miglustat administration in NPC1−/− mice was able to rescue synaptic plasticity deficits, to restore ERKs activation and to counteract hyperexcitability. Overall, these data indicate that Miglustat may be effective for treating the neurological deficits associated with NPCD, such as seizures and dementia. PMID:26885401

  5. Niemann-Pick C1-Like 1 (NPC1L1) Protein in Intestinal and Hepatic Cholesterol Transport

    PubMed Central

    Jia, Lin; Betters, Jenna L.; Yu, Liqing

    2014-01-01

    Increased blood cholesterol is an independent risk factor for atherosclerotic cardiovascular disease. Cholesterol homeostasis in the body is controlled mainly by endogenous synthesis, intestinal absorption, and hepatic excretion. Niemann-Pick C1-Like 1 (NPC1L1) is a polytopic transmembrane protein localized at the apical membrane of enterocytes and the canalicular membrane of hepatocytes. It functions as a sterol transporter to mediate intestinal cholesterol absorption and counterbalances hepatobiliary cholesterol excretion. NPC1L1 is the molecular target of ezetimibe, a potent cholesterol absorption inhibitor that is widely used in treating hypercholesterolemia. Recent findings suggest that NPC1L1 deficiency or ezetimibe treatment also prevents diet-induced hepatic steatosis and obesity in addition to reducing blood cholesterol. Future studies should focus on molecular mechanisms underlying NPC1L1-dependent cholesterol transport and elucidation of how a cholesterol transporter modulates the pathogenesis of metabolic diseases. PMID:20809793

  6. Dynamic performance and control of a static var generator using cascade multilevel inverters

    SciTech Connect

    Peng, Fang Zheng; Lai, Jih-Sheng

    1996-10-01

    A cascade multilevel inverter is proposed for static VAR shifting, compensation/generation applications. The new cascade M-level inverter consists of (M-1)/2 single-phase full bridges in which each bridge has its own separate dc source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle. It can eliminate the need for transformers in multipulse inverters. A prototype static VAR generator (SVG) system using 11- level cascade inverter (21-level line-to-line voltage waveform) has been built. The output voltage waveform is equivalent to that of a 60- pulse inverter. This paper focuses on dynamic performance of the cascade inverter based SVG system. Control schemes are proposed to achieve a fast response which is impossible for a conventional static VAR compensator (SVC). Analytical, simulated and experimental results show the superiority of the proposed SVG system.

  7. The NPC1L1 Polymorphism 1679C>G Is Associated with Gallstone Disease in Chinese Patients

    PubMed Central

    Fei, Jian; Zhang, Sheng-Dao; Han, Tian-Quan; Hu, Hai; Jiang, Zhao-Yan

    2016-01-01

    Niemann Pick Type C1 Like 1 (NPC1L1) protein plays a key role in intestinal and hepatic cholesterol metabolism in humans. Genetic variation in NPC1L1 has been widely studied in recent years. We analyzed NPC1L1 single nucleotide polymorphisms in Chinese gallstone disease patients to investigate their association with gallstone disease. NPC1L1 mRNA expression was also measured in liver biopsies from patients with cholesterol gallstone disease and compared between genotypes. The G allele of the g1679C>G (rs2072183) polymorphism was significantly more prevalent in patients with gallstones compared with gallstone-free subjects. Moreover, patients carrying the G allele had lower hepatic NPC1L1 mRNA expression and higher biliary cholesterol (molar percentages) and cholesterol saturation index. Our study suggests that the G allele of the NPC1L1 polymorphism g1679C>G may be a positive marker of gallstone formation risk. PMID:26800364

  8. The NPC1L1 Polymorphism 1679C>G Is Associated with Gallstone Disease in Chinese Patients.

    PubMed

    Wu, Jian; Cui, Wei; Cai, Qu; Fei, Jian; Zhang, Sheng-Dao; Han, Tian-Quan; Hu, Hai; Jiang, Zhao-Yan

    2016-01-01

    Niemann Pick Type C1 Like 1 (NPC1L1) protein plays a key role in intestinal and hepatic cholesterol metabolism in humans. Genetic variation in NPC1L1 has been widely studied in recent years. We analyzed NPC1L1 single nucleotide polymorphisms in Chinese gallstone disease patients to investigate their association with gallstone disease. NPC1L1 mRNA expression was also measured in liver biopsies from patients with cholesterol gallstone disease and compared between genotypes. The G allele of the g1679C>G (rs2072183) polymorphism was significantly more prevalent in patients with gallstones compared with gallstone-free subjects. Moreover, patients carrying the G allele had lower hepatic NPC1L1 mRNA expression and higher biliary cholesterol (molar percentages) and cholesterol saturation index. Our study suggests that the G allele of the NPC1L1 polymorphism g1679C>G may be a positive marker of gallstone formation risk. PMID:26800364

  9. Cholesterol homeostatic responses provide biomarkers for monitoring treatment for the neurodegenerative disease Niemann–Pick C1 (NPC1)

    PubMed Central

    Tortelli, Brett; Fujiwara, Hideji; Bagel, Jessica H.; Zhang, Jessie; Sidhu, Rohini; Jiang, Xuntian; Yanjanin, Nicole M.; Shankar, Roopa Kanakatti; Carillo-Carasco, Nuria; Heiss, John; Ottinger, Elizabeth; Porter, Forbes D.; Schaffer, Jean E.; Vite, Charles H.; Ory, Daniel S.

    2014-01-01

    Niemann–Pick C1 (NPC1) disease is a rare, neurodegenerative lysosomal cholesterol storage disorder, typified by progressive cognitive and motor function impairment. Affected individuals usually succumb to the disease in adolescence. 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) has emerged as a promising intervention that reduces lipid storage and prolongs survival in NPC1 disease animal models. A barrier to the development of HP-β-CD and other treatments for NPC disease has been the lack of validated biochemical measures to evaluate efficacy. Here we explored whether cholesterol homeostatic responses resulting from HP-β-CD-mediated redistribution of sequestered lysosomal cholesterol could provide biomarkers to monitor treatment. Upon direct CNS delivery of HP-β-CD, we found increases in plasma 24(S)-HC in two independent NPC1 disease animal models, findings that were confirmed in human NPC1 subjects receiving HP-β-CD. Since circulating 24(S)-HC is almost exclusively CNS-derived, the increase in plasma 24(S)-HC provides a peripheral, non-invasive measure of the CNS effect of HP-β-CD. Our findings suggest that plasma 24(S)-HC, along with the other cholesterol-derived markers examined in this study, can serve as biomarkers that will accelerate development of therapeutics for NPC1 disease. PMID:24964810

  10. Intelligent Control of an Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Rekdalsbakken, Webjorn

    An inverted pendulum represents an unstable system which is excellent for demonstrating the use of feedback control with different kinds of control strategies. In this work state feedback of the inverted pendulum is examined. First a pole placement algorithm is explored. After that artificial intelligence (AI) methods are investigated to better cope with the nonlinearities of the physical model. The technique used is based on a hybrid system combining a neural network (NN) with a genetic algorithm (GA). The NN controller is trained by the GA against the behaviour of the physical model. The results of the training process show that the chromosome population tends to station at a suboptimal level, and that changes in the environmental parameters have to take place to reach a new optimal level. By systematically changing these parameters the NN controller will gradually adapt to the pendulum behaviour.

  11. Coaxial inverted geometry transistor having buried emitter

    NASA Technical Reports Server (NTRS)

    Hruby, R. J.; Cress, S. B.; Dunn, W. R. (Inventor)

    1973-01-01

    The invention relates to an inverted geometry transistor wherein the emitter is buried within the substrate. The transistor can be fabricated as a part of a monolithic integrated circuit and is particularly suited for use in applications where it is desired to employ low actuating voltages. The transistor may employ the same doping levels in the collector and emitter, so these connections can be reversed.

  12. A study on the impact of high penetration distributed generation inverters on grid operation and stability

    NASA Astrophysics Data System (ADS)

    Gu, Fei; Brouwer, Jack; Samuelsen, Scott

    2013-09-01

    Recent advances in inverter technology have enabled ancillary services such as volt/VAR regulation, SCADA communications, and active power filtering. Smart inverters can not only provide real power, but can be controlled to use excess capacity to provide reactive power compensation, power flow control, and active power filtering without supplementary inverter hardware. A transient level inverter model based on the Solectria 7700 inverter is developed and used to assess these control strategies using field data from an existing branch circuit containing two Amonix 68kW CPV-7700 systems installed at the University of California, Irvine.

  13. An inverter/controller subsystem optimized for photovoltaic applications

    NASA Technical Reports Server (NTRS)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  14. Nanowire NMOS Logic Inverter Characterization.

    PubMed

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly. PMID:27427653

  15. Inverter Ground Fault Overvoltage Testing

    SciTech Connect

    Hoke, Andy; Nelson, Austin; Chakraborty, Sudipta; Chebahtah, Justin; Wang, Trudie; McCarty, Michael

    2015-08-12

    This report describes testing conducted at NREL to determine the duration and magnitude of transient overvoltages created by several commercial PV inverters during ground fault conditions. For this work, a test plan developed by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Load rejection overvoltage test results were reported previously in a separate technical report.

  16. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) DIRECT FOOD....1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an aqueous solution of inverted...

  17. Orlistat limits cholesterol intestinal absorption by Niemann-pick C1-like 1 (NPC1L1) inhibition.

    PubMed

    Alqahtani, Saeed; Qosa, Hisham; Primeaux, Brian; Kaddoumi, Amal

    2015-09-01

    The known mechanism by which orlistat decreases the absorption of dietary cholesterol is by inhibition of intestinal lipases. The aim of this study was to investigate the ability of orlistat to limit cholesterol absorption by inhibition of the cholesterol transport protein Niemann-Pick C1-like 1 (NPC1L1) as another mechanism of action. In situ rat intestinal perfusion studies were conducted to study the effect of orlistat on jejunal cholesterol absorption. Inhibition kinetic parameters were calculated from in vitro inhibition studies using Caco2 and NPC1L1 transfected cell lines. The in situ studies demonstrated that intestinal perfusion of orlistat (100µM) was able to reduce cholesterol absorption by three-fold when compared to control (i.e. in the absence of orlistat, P<0.01). In vitro studies using Caco2 cells demonstrated orlistat to reduce the cellular uptake of cholesterol by 30%. Additionally, orlistat reduced the cellular uptake of cholesterol in dose dependent manner in NPC1L1 transfected cell line with an IC50=1.2µM. Lineweaver-Burk plot indicated a noncompetitive inhibition of NPC1L1 by orlistat. Beside the already established mechanism by which orlistat reduces the absorption of cholesterol, we demonstrated for the first time that orlistat limits cholesterol absorption by the inhibition of NPC1L1 transport protein. PMID:26048312

  18. A Nup133-dependent NPC-anchored network tethers centrosomes to the nuclear envelope in prophase

    PubMed Central

    Bolhy, Stéphanie; Bouhlel, Imène; Dultz, Elisa; Nayak, Tania; Zuccolo, Michela; Gatti, Xavier; Vallee, Richard; Ellenberg, Jan

    2011-01-01

    Centrosomes are closely associated with the nuclear envelope (NE) throughout the cell cycle and this association is maintained in prophase when they separate to establish the future mitotic spindle. At this stage, the kinetochore constituents CENP-F, NudE, NudEL, dynein, and dynactin accumulate at the NE. We demonstrate here that the N-terminal domain of the nuclear pore complex (NPC) protein Nup133, although largely dispensable for NPC assembly, is required for efficient anchoring of the dynein/dynactin complex to the NE in prophase. Nup133 exerts this function through an interaction network via CENP-F and NudE/EL. We show that this molecular chain is critical for maintaining centrosome association with the NE at mitotic entry and contributes to this process without interfering with the previously described RanBP2–BICD2-dependent pathway of centrosome anchoring. Finally, our study reveals that tethering of centrosomes to the nuclear surface at the G2/M transition contributes, along with other cellular mechanisms, to early stages of bipolar spindle assembly. PMID:21383080

  19. Npc1 deficiency in the C57BL/6J genetic background enhances Niemann-Pick disease type C spleen pathology.

    PubMed

    Parra, Julio; Klein, Andrés D; Castro, Juan; Morales, María Gabriela; Mosqueira, Matías; Valencia, Ilse; Cortés, Victor; Rigotti, Attilio; Zanlungo, Silvana

    2011-09-30

    Niemann-Pick type C (NPC) disease is an autosomal recessive neurovisceral lipid storage disorder. The affected genes are NPC1 and NPC2. Mutations in either gene lead to intracellular cholesterol accumulation. There are three forms of the disease, which are categorized based on the onset and severity of the disease: the infantile form, in which the liver and spleen are severely affected, the juvenile form, in which the liver and brain are affected, and the adult form, which affects the brain. In mice, a spontaneous mutation in the Npc1 gene originated in the BALB/c inbred strain mimics the juvenile form of the disease. To study the influence of genetic background on the expression of NPC disease in mice, we transferred the Npc1 mutation from the BALB/c to C57BL/6J inbred background. We found that C57BL/6J-Npc1(-/-) mice present with a much more aggressive form of the disease, including a shorter lifespan than BALB/c-Npc1(-/-) mice. Surprisingly, there was no difference in the amount of cholesterol in the brains of Npc1(-/-) mice of either mouse strain. However, Npc1(-/-) mice with the C57BL/6J genetic background showed striking spleen damage with a marked buildup of cholesterol and phospholipids at an early age, which correlated with large foamy cell clusters. In addition, C57BL/6J Npc1(-/-) mice presented red cell abnormalities and abundant ghost erythrocytes that correlated with a lower hemoglobin concentration. We also found abnormalities in white cells, such as cytoplasmic granulation and neutrophil hypersegmentation that included lymphopenia and atypias. In conclusion, Npc1 deficiency in the C57BL6/J background is associated with spleen, erythrocyte, and immune system abnormalities that lead to a reduced lifespan. PMID:21910975

  20. All-trans retinoic acid-triggered antimicrobial activity against Mycobacterium tuberculosis is dependent on NPC2.

    PubMed

    Wheelwright, Matthew; Kim, Elliot W; Inkeles, Megan S; De Leon, Avelino; Pellegrini, Matteo; Krutzik, Stephan R; Liu, Philip T

    2014-03-01

    A role for vitamin A in host defense against Mycobacterium tuberculosis has been suggested through epidemiological and in vitro studies; however, the mechanism is unclear. In this study, we demonstrate that vitamin A-triggered antimicrobial activity against M. tuberculosis requires expression of NPC2. Comparison of monocytes stimulated with all-trans retinoic acid (ATRA) or 1,25-dihydroxyvitamin D3 (1,25D3), the biologically active forms of vitamin A and vitamin D, respectively, indicates that ATRA and 1,25D3 induce mechanistically distinct antimicrobial activities. Stimulation of primary human monocytes with ATRA did not result in expression of the antimicrobial peptide cathelicidin, which is required for 1,25D3 antimicrobial activity. In contrast, ATRA triggered a reduction in the total cellular cholesterol concentration, whereas 1,25D3 did not. Blocking ATRA-induced cellular cholesterol reduction inhibits antimicrobial activity as well. Bioinformatic analysis of ATRA- and 1,25D3-induced gene profiles suggests that NPC2 is a key gene in ATRA-induced cholesterol regulation. Knockdown experiments demonstrate that ATRA-mediated decrease in total cellular cholesterol content and increase in lysosomal acidification are both dependent upon expression of NPC2. Expression of NPC2 was lower in caseous tuberculosis granulomas and M. tuberculosis-infected monocytes compared with normal lung and uninfected cells, respectively. Loss of NPC2 expression ablated ATRA-induced antimicrobial activity. Taken together, these results suggest that the vitamin A-mediated antimicrobial mechanism against M. tuberculosis requires NPC2-dependent expression and function, indicating a key role for cellular cholesterol regulation in the innate immune response. PMID:24501203

  1. Level IIb CTV delineation based on cervical fascia anatomy in nasopharyngeal cancer.

    PubMed

    Zhang, Jun; Pan, Li; Ren, Jing; Lang, Jinyi; Wen, Hao; Wang, Jie; Zhang, Shichuan

    2015-04-01

    We carefully reviewed magnetic resonance (MR) images from 100 consecutive NPC patients and analyzed the lymph node distribution status at level IIb. We proposed several modifications of the existing consensus guidelines for determining the level IIb clinical target volume (CTV) in NPC patients. PMID:25770873

  2. Characterization of a Spontaneous Novel Mutation in the NPC2 Gene in a Cat Affected by Niemann Pick Type C Disease

    PubMed Central

    Zampieri, Stefania; Bianchi, Ezio; Cantile, Carlo; Saleri, Roberta; Bembi, Bruno; Dardis, Andrea

    2014-01-01

    Niemann-Pick C disease (NPC) is an autosomal recessive lysosomal storage disorder characterized by accumulation of unesterified cholesterol and other lipids within the lysosomes due to mutation in NPC1 or NPC2 genes. A feline model of NPC carrying a mutation in NPC1 gene has been previously described. We have identified two kittens affected by NPC disease due to a mutation in NPC2 gene. They manifested with tremors at the age of 3 months, which progressed to dystonia and severe ataxia. At 6 months of age cat 2 was unable to stand without assistance and had bilaterally reduced menace response. It died at the age of 10 months. Post-mortem histological analysis of the brain showed the presence of neurons with cytoplasmic swelling and vacuoles, gliosis of the substantia nigra and degeneration of the white matter. Spheroids with accumulation of ubiquitinated aggregates were prominent in the cerebellar cortex. Purkinje cells were markedly reduced in number and they showed prominent intracytoplasmic storage. Scattered perivascular aggregates of lymphocytes and microglial cells proliferation were present in the thalamus and midbrain. Proliferation of Bergmann glia was also observed. In the liver, hepatocytes were swollen because of accumulation of small vacuoles and foamy Kupffer cells were also detected. Foamy macrophages were observed within the pulmonary interstitium and alveoli as well. At 9 months cat 1 was unable to walk, developed seizures and it was euthanized at 21 months. Filipin staining of cultured fibroblasts showed massive storage of unesterified cholesterol. Molecular analysis of NPC1 and NPC2 genes showed the presence of a homozygous intronic mutation (c.82+5G>A) in the NPC2 gene. The subsequent analysis of the mRNA showed that the mutation causes the retention of 105 bp in the mature mRNA, which leads to the in frame insertion of 35 amino acids between residues 28 and 29 of NPC2 protein (p.G28_S29ins35). PMID:25396745

  3. Inverter design for high frequency power distribution

    NASA Technical Reports Server (NTRS)

    King, R. J.

    1985-01-01

    A class of simple resonantly commutated inverters are investigated for use in a high power (100 KW - 1000 KW) high frequency (10 KHz - 20 KHz) AC power distribution system. The Mapham inverter is found to provide a unique combination of large thyristor turn-off angle and good utilization factor, much better than an alternate 'current-fed' inverter. The effects of loading the Mapham inverter entirely with rectifier loads are investigated by simulation and with an experimental 3 KW 20 KHz inverter. This inverter is found to be well suited to a power system with heavy rectifier loading.

  4. Microgrid and Inverter Control and Simulator Software

    SciTech Connect

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than the simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.

  5. Advanced Modular Inverter Technology Development

    SciTech Connect

    Adam Szczepanek

    2006-02-04

    Electric and hybrid-electric vehicle systems require an inverter to convert the direct current (DC) output of the energy generation/storage system (engine, fuel cells, or batteries) to the alternating current (AC) that vehicle propulsion motors use. Vehicle support systems, such as lights and air conditioning, also use the inverter AC output. Distributed energy systems require an inverter to provide the high quality AC output that energy system customers demand. Today's inverters are expensive due to the cost of the power electronics components, and system designers must also tailor the inverter for individual applications. Thus, the benefits of mass production are not available, resulting in high initial procurement costs as well as high inverter maintenance and repair costs. Electricore, Inc. (www.electricore.org) a public good 501 (c) (3) not-for-profit advanced technology development consortium assembled a highly qualified team consisting of AeroVironment Inc. (www.aerovironment.com) and Delphi Automotive Systems LLC (Delphi), (www.delphi.com), as equal tiered technical leads, to develop an advanced, modular construction, inverter packaging technology that will offer a 30% cost reduction over conventional designs adding to the development of energy conversion technologies for crosscutting applications in the building, industry, transportation, and utility sectors. The proposed inverter allows for a reduction of weight and size of power electronics in the above-mentioned sectors and is scalable over the range of 15 to 500kW. The main objective of this program was to optimize existing AeroVironment inverter technology to improve power density, reliability and producibility as well as develop new topology to reduce line filter size. The newly developed inverter design will be used in automotive and distribution generation applications. In the first part of this program the high-density power stages were redesigned, optimized and fabricated. One of the main tasks

  6. Inverting an Introductory Statistics Classroom

    ERIC Educational Resources Information Center

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  7. Update on SIC-Based Inverter Technology

    SciTech Connect

    Chinthavali, Madhu Sudhan; Zhang, Hui; Tolbert, Leon M; Ozpineci, Burak

    2009-01-01

    This paper presents a study of silicon carbide (SiC) technology which includes device characterization and modeling, inverter simulation, and test results for several prototype inverters. The static and dynamic characteristics of discrete devices and half bridge modules are presented. Test results of a 55 kW hybrid inverter with SiC Schottky diodes and an 18 kW all-SiC inverter using SiC JFETs and Schottky diodes are demonstrated.

  8. Effect of NPC-14686 (Fmoc-l-Homophenylalanine) on Ca²⁺ Homeostasis and Viability in OC2 Human Oral Cancer Cells.

    PubMed

    Li, Yih-Do; Chou, Chiang-Ting; Liang, Wei-Zhe; Tseng, Hui-Wen; Fang, Yi-Chien; Hung, Tzu-Yi; Chang, Hong-Tai; Kuo, Daih-Huang; Kuo, Chun-Chi; Ho, Chin-Man; Shieh, Pochuen; Chen, Fu-An; Jan, Chung-Ren

    2015-10-31

    The effect of the anti-inflammatory compound NPC-14686 on intracellular Ca²⁺ concentration ([Ca²⁺](i)) and viability in OC2 human oral cancer cells was investigated. The Ca²⁺-sensitive fluorescent probe fura-2 was used to examine [Ca²⁺](i). NPC-14686 induced [Ca²⁺](i) rises in a concentration-dependent fashion. The effect was reduced approximately by 10% by removing extracellular Ca²⁺. NPC-14686- elicited Ca²⁺ signal was decreased by nifedipine, econazole, SKF96365, and GF109203X. In Ca²⁺-free medium, incubation with the endoplasmic reticulum Ca²⁺ pump inhibitor thapsigargin or 2,5-di-tert-butylhydroquinone (BHQ) abolished NPC-14686-induced [Ca²⁺](i) rises. Conversely, pretreatment with NPC-14686 abolished thapsigargin or BHQ-induced [Ca²⁺](i) rises. Inhibition of phospholipase C with U73122 abolished NPC-14686-induced [Ca²⁺](i) rises. At 20-100 μM, NPC-14686 inhibited cell viability, which was not reversed by chelating cytosolic Ca²⁺ with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'- tetraacetic acid-acetoxymethyl ester (BAPTA/AM). NPC-14686 between 20 μM and 40 μM also induced apoptosis. Collectively, in OC2 cells, NPC-14686 induced [Ca²⁺](i) rises by evoking phospholipase C-dependent Ca²⁺ release from the endoplasmic reticulum and Ca²⁺ entry via protein kinase C-regulated store-operated Ca²⁺ channels. NPC-14686 also caused Ca²⁺-independent apoptosis. PMID:26387652

  9. Improved Performance via the Inverted Classroom

    ERIC Educational Resources Information Center

    Weinstein, Randy D.

    2015-01-01

    This study examined student performance in an inverted thermodynamics course (lectures provided by video outside of class) compared to a traditional lecture class. Students in the inverted class performed better on their exams. Students in the bottom third of the inverted course showed the greatest improvement. These bottom third students had a C…

  10. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  11. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  12. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  13. 21 CFR 184.1859 - Invert sugar.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Invert sugar. 184.1859 Section 184.1859 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1859 Invert sugar. (a) Invert sugar (CAS Reg. No. 8013-17-0) is an...

  14. Thermal Study of Inverter Components: Preprint

    SciTech Connect

    Sorensen, N. R.; Thomas, E. V.; Quintana, M. A.; Barkaszi, S.; Rosenthal, A.; Zhang, Z.; Kurtz, S.

    2012-06-01

    Thermal histories of inverter components were collected from operating inverters from several manufacturers and three locations. The data were analyzed to determine thermal profiles, the dependence on local conditions, and to assess the effect on inverter reliability. Inverter temperatures were shown to increase with the power dissipation of the inverters, follow diurnal and annual cycles, and have a dependence on wind speed. An accumulated damage model was applied to the temperature profiles and an example of using these data to predict reliability was explored.

  15. Evaluation of recent residential inverters

    SciTech Connect

    Nichols, B.E.

    1982-06-01

    Seven residential utility-interactive inverters for photovoltaic power systems have been evaluated at MIT Laboratory and at the Northeast Residential Experiment Station (NE RES). Two, a Windworks Gemini and an Abacus Sunverter, have been reported on previously. Reviewed here are five other inverters: Windworks Gemini 8-kW (dc) model with an ac filter to improve the output current waveform and power factor; Acheval Wind Electronics 10-kW (ac) model, Helionetics 6-kW (dc) model; and American Power Conversion 2-kW and 4-kW (ac) models. Input and output power, power factor, current waveform distortion, audio noise and radio frequency interference measurements were made at the NE RES and the results are presented.

  16. Effective switching frequency multiplier inverter

    SciTech Connect

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  17. The Inverted Snow Globe Shadow

    NASA Astrophysics Data System (ADS)

    Ribeiro, Jair Lúcio Prados

    2015-01-01

    Our high school optics course finishes with an assignment that students usually appreciate. They must take pictures of everyday situations representing optical phenomena such as reflection, refraction, or dispersion, and post them on Instagram.1 When the photos were presented to the class, one student revealed an intriguing photo, similar to Fig. 1, showing a snow globe exposed to sunlight and its inverted shadow. This paper offers an explanation of the problem, which occurs due to light refraction from the globe.

  18. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, Richard L.; Killian, Mark A.

    1993-01-01

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  19. Gripper deploying and inverting linkage

    DOEpatents

    Minichan, R.L.; Killian, M.A.

    1993-03-02

    An end effector deploying and inverting linkage. The linkage comprises an air cylinder mounted in a frame or tube, a sliding bracket next to the air cylinder, a stopping bracket depending from the frame and three, pivotally-attached links that are attached to the end effector and to each other in such a way as to be capable of inverting the end effector and translating it laterally. The first of the three links is a straight element that is moved up and down by the shaft of the air cylinder. The second link is attached at one end to the stopping bracket and to the side of the end effector at the other end. The first link is attached near the middle of the second, sharply angled link so that, as the shaft of the air cylinder moves up and down, the second link rotates about an axis perpendicular to the frame and inverts and translates the end effector. The rotation of the second link is stopped at both ends when the link engages stops on the stopping bracket. The third link, slightly angled, is attached to the sliding bracket at one end and to the end of the end effector at the other. The third helps to control the end effector in its motion.

  20. Three-phase multilevel solar inverter for motor drive system

    NASA Astrophysics Data System (ADS)

    Bhasagare, Mayuresh P.

    This thesis deals with three phase inverters and the different control strategies that can be associated with an inverter being used together. The first part of this thesis discusses the present research in the fields of PV panels, motor drive systems and three phase inverters along with their control. This control includes various strategies like MPPT, Volts-Hertz and modulation index compensation. Incorporating these techniques together is the goal of this thesis. A new topology for operating an open end motor drive system has also been discusses, where a boost converter and a flyback converter have been used in cascade to run a three phase motor. The main advantage of this is increasing the number of levels and improving the quality of the output voltage, not to mention a few other benefits of having the proposed circuit. A new algorithm has also been designed for starting and stopping the motor, which controls the current drawn from the power source during starting.

  1. Suspended Patch Antenna Array With Electromagnetically Coupled Inverted Microstrip Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2000-01-01

    The paper demonstrates a four-element suspended patch antenna array, with a parasitic patch layer and an electromagnetically coupled inverted microstrip feed, for linear polarization at K-Band frequencies. This antenna has the following advantages over conventional microstrip antennas: First, the inverted microstrip has lower attenuation than conventional microstrip; hence, conductor loss associated with the antenna corporate feed is lower resulting in higher gain and efficiency. Second, conventional proximity coupled patch antennas require a substrate for the feed and a superstrate for the patch. However, the inverted microstrip fed patch antenna makes use of a single substrate, and hence, is lightweight and low cost. Third, electromagnetic coupling results in wider bandwidth. Details regarding the design and fabrication will be presented as well as measured results including return loss, radiation patterns and cross-polarization levels.

  2. Normalization of Cholesterol Homeostasis by 2-Hydroxypropyl-β-cyclodextrin in Neurons and Glia from Niemann-Pick C1 (NPC1)-deficient Mice*

    PubMed Central

    Peake, Kyle B.; Vance, Jean E.

    2012-01-01

    Niemann-Pick C (NPC) disease is an inherited, progressive neurodegenerative disorder caused by mutations in the NPC1 or NPC2 gene that result in an accumulation of unesterified cholesterol in late endosomes/lysosomes (LE/L) and impaired export of cholesterol from LE/L to the endoplasmic reticulum (ER). Recent studies demonstrate that administration of cyclodextrin (CD) to Npc1−/− mice eliminates cholesterol sequestration in LE/L of many tissues, including the brain, delays neurodegeneration, and increases lifespan of the mice. We have now investigated cholesterol homeostasis in NPC1-deficient cells of the brain in response to CD. Primary cultures of neurons and glial cells from Npc1−/− mice were incubated for 24 h with 0.1 to 10 mm CD after which survival and cholesterol homeostasis were monitored. Although 10 mm CD was profoundly neurotoxic, and altered astrocyte morphology, 0.1 and 1 mm CD were not toxic but effectively mobilized stored cholesterol from the LE/L as indicated by filipin staining. However, 0.1 and 1 mm CD altered cholesterol homeostasis in opposite directions. The data suggest that 0.1 mm CD releases cholesterol trapped in LE/L of neurons and astrocytes and increases cholesterol availability at the ER, whereas 1 mm CD primarily extracts cholesterol from the plasma membrane and reduces ER cholesterol. These studies in Npc1−/− neurons and astrocytes establish a dose of CD (0.1 mm) that would likely be beneficial in NPC disease. The findings are timely because treatment of NPC disease patients with CD is currently being initiated. PMID:22277650

  3. Identification of NPC1 as the target of U18666A, an inhibitor of lysosomal cholesterol export and Ebola infection

    PubMed Central

    Lu, Feiran; Liang, Qiren; Abi-Mosleh, Lina; Das, Akash; De Brabander, Jef K; Goldstein, Joseph L; Brown, Michael S

    2015-01-01

    Niemann-Pick C1 (NPC1) is a lysosomal membrane protein that exports cholesterol derived from receptor-mediated uptake of LDL, and it also mediates cellular entry of Ebola virus. Cholesterol export is inhibited by nanomolar concentrations of U18666A, a cationic sterol. To identify the target of U18666A, we synthesized U-X, a U18666A derivative with a benzophenone that permits ultraviolet-induced crosslinking. When added to CHO cells, U-X crosslinked to NPC1. Crosslinking was blocked by U18666A derivatives that block cholesterol export, but not derivatives lacking blocking activity. Crosslinking was prevented by point mutation in the sterol-sensing domain (SSD) of NPC1, but not by point mutation in the N-terminal domain (NTD). These data suggest that the SSD contains a U18666A-inhibitable site required for cholesterol export distinct from the cholesterol-binding site in the NTD. Inasmuch as inhibition of Ebola requires 100-fold higher concentrations of U18666A, the high affinity U16888A-binding site is likely not required for virus entry. DOI: http://dx.doi.org/10.7554/eLife.12177.001 PMID:26646182

  4. Identification of NPC1 as the target of U18666A, an inhibitor of lysosomal cholesterol export and Ebola infection.

    PubMed

    Lu, Feiran; Liang, Qiren; Abi-Mosleh, Lina; Das, Akash; De Brabander, Jef K; Goldstein, Joseph L; Brown, Michael S

    2015-01-01

    Niemann-Pick C1 (NPC1) is a lysosomal membrane protein that exports cholesterol derived from receptor-mediated uptake of LDL, and it also mediates cellular entry of Ebola virus. Cholesterol export is inhibited by nanomolar concentrations of U18666A, a cationic sterol. To identify the target of U18666A, we synthesized U-X, a U18666A derivative with a benzophenone that permits ultraviolet-induced crosslinking. When added to CHO cells, U-X crosslinked to NPC1. Crosslinking was blocked by U18666A derivatives that block cholesterol export, but not derivatives lacking blocking activity. Crosslinking was prevented by point mutation in the sterol-sensing domain (SSD) of NPC1, but not by point mutation in the N-terminal domain (NTD). These data suggest that the SSD contains a U18666A-inhibitable site required for cholesterol export distinct from the cholesterol-binding site in the NTD. Inasmuch as inhibition of Ebola requires 100-fold higher concentrations of U18666A, the high affinity U16888A-binding site is likely not required for virus entry. PMID:26646182

  5. Repetition probability effects for inverted faces.

    PubMed

    Grotheer, Mareike; Hermann, Petra; Vidnyánszky, Zoltán; Kovács, Gyula

    2014-11-15

    It has been shown, that the repetition related reduction of the blood-oxygen level dependent (BOLD) signal is modulated by the probability of repetitions (P(rep)) for faces (Summerfield et al., 2008), providing support for the predictive coding (PC) model of visual perception (Rao and Ballard, 1999). However, the stage of face processing where repetition suppression (RS) is modulated by P(rep) is still unclear. Face inversion is known to interrupt higher level configural/holistic face processing steps and if modulation of RS by P(rep) takes place at these stages of face processing, P(rep) effects are expected to be reduced for inverted when compared to upright faces. Therefore, here we aimed at investigating whether P(rep) effects on RS observed for face stimuli originate at the higher-level configural/holistic stages of face processing by comparing these effects for upright and inverted faces. Similarly to previous studies, we manipulated P(rep) for pairs of stimuli in individual blocks of fMRI recordings. This manipulation significantly influenced repetition suppression in the posterior FFA, the OFA and the LO, independently of stimulus orientation. Our results thus reveal that RS in the ventral visual stream is modulated by P(rep) even in the case of face inversion and hence strongly compromised configural/holistic face processing. An additional whole-brain analysis could not identify any areas where the modulatory effect of probability was orientation specific either. These findings imply that P(rep) effects on RS might originate from the earlier stages of face processing. PMID:25123974

  6. Familial inverted duplication 7p

    SciTech Connect

    Schaefer, G.B.; Novak, K.; Steele, D.

    1995-03-27

    A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2{r_arrow}p13 portion of chromosome 7(46,XX,dup(7)(p13p12.2)). The proposita`s older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication. 5 refs., 3 figs., 1 tab.

  7. System and method for regulating resonant inverters

    DOEpatents

    Stevanovic, Ljubisa Dragoljub; Zane, Regan Andrew

    2007-08-28

    A technique is provided for direct digital phase control of resonant inverters based on sensing of one or more parameters of the resonant inverter. The resonant inverter control system includes a switching circuit for applying power signals to the resonant inverter and a sensor for sensing one or more parameters of the resonant inverter. The one or more parameters are representative of a phase angle. The resonant inverter control system also includes a comparator for comparing the one or more parameters to a reference value and a digital controller for determining timing of the one or more parameters and for regulating operation of the switching circuit based upon the timing of the one or more parameters.

  8. Microgrid and Inverter Control and Simulator Software

    Energy Science and Technology Software Center (ESTSC)

    2012-09-13

    A collection of software that can simulate the operation of an inverter on a microgrid or control a real inverter. In addition, it can simulate the control of multiple nodes on a microgrid." Application: Simulation of inverters and microgrids; control of inverters on microgrids." The MMI submodule is designed to control custom inverter hardware, and to simulate that hardware. The INVERTER submodule is only the simulator code, and is of an earlier generation than themore » simulator in MMI. The MICROGRID submodule is an agent-based simulator of multiple nodes on a microgrid which presents a web interface. The WIND submodule produces movies of wind data with a web interface.« less

  9. Multilevel Inverters for Electric Vehicle Applications

    SciTech Connect

    Habetler, T.G.; Peng, F.Z.; Tolbert, L.M.

    1998-10-22

    This paper presents multilevel inverters as an application for all-electric vehicle (EV) and hybrid-electric vehicle (HEV) motor drives. Diode-clamped inverters and cascaded H-bridge inverters, (1) can generate near-sinusoidal voltages with only fundamental frequency switching; (2) have almost no electromagnetic interference (EMI) and common-mode voltage; and (3) make an EV more accessible/safer and open wiring possible for most of an EV'S power system. This paper explores the benefits and discusses control schemes of the cascade inverter for use as an EV motor drive or a parallel HEV drive and the diode-clamped inverter as a series HEV motor drive. Analytical, simulated, and experimental results show the superiority of these multilevel inverters for this new niche.

  10. Cascaded H-bridge multilevel inverter for renewable energy generation

    NASA Astrophysics Data System (ADS)

    Pandey, Ravikant; Nath Tripathi, Ravi; Hanamoto, Tsuyoshi

    2016-04-01

    In this paper cascaded H-bridge multilevel inverter (CHBMLI) has been investigated for the application of renewable energy generation. Energy sources like solar, wind, hydro, biomass or combination of these can be manipulated to obtain alternative sources for renewable energy generation. These renewable energy sources have different electrical characteristics like DC or AC level so it is challenging to use generated power by connecting to grid or load directly. The renewable energy source require specific power electronics converter as an interface for conditioning generated power .The multilevel inverter can be utilized for renewable energy sources in two different modes, the power generation mode (stand-alone mode), and compensator mode (statcom). The performance of the multilevel inverter has been compared with two level inverter. In power generation mode CHBMLI supplies the active and reactive power required by the different loads. For operation in compensator mode the indirect current control based on synchronous reference frame theory (SRFT) ensures the grid operating in unity power factor and compensate harmonics and reactive power.

  11. Structure-activity relationship study of non-steroidal NPC1L1 ligands identified through cell-based assay using pharmacological chaperone effect as a readout.

    PubMed

    Karaki, Fumika; Ohgane, Kenji; Fukuda, Hiromitsu; Nakamura, Masahiko; Dodo, Kosuke; Hashimoto, Yuichi

    2014-07-15

    Niemann-Pick type C1-like 1 (NPC1L1) is an intestinal cholesterol transporter that is known to be the target of the cholesterol absorption inhibitor ezetimibe. We previously discovered steroidal NPC1L1 ligands by using a novel cell-based assay that employs pharmacological chaperone effect as a readout. Those steroid derivatives bound to a site different from both the sterol-binding domain and the ezetimibe-binding site, implying that they may be a novel class of NPC1L1 inhibitors with a distinct mode of action. As an extension of that work, we aimed here to find non-steroidal NPC1L1 ligands, which may be better candidates for clinical application than steroidal ligands, by using the same assay to screen our focused library of ligands for liver X receptor (LXR), a nuclear receptor that recognizes oxysterols as endogenous ligands. Here we describe identification of a novel class of NPC1L1 ligands with a ring-fused quinolinone scaffold, and an analysis of the structure-activity relationships of their derivatives as NPC1L1 ligands. PMID:24906511

  12. A single-phase embedded Z-source DC-AC inverter.

    PubMed

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  13. A Single-Phase Embedded Z-Source DC-AC Inverter

    PubMed Central

    Kim, Se-Jin; Lim, Young-Cheol

    2014-01-01

    In the conventional DC-AC inverter consisting of two DC-DC converters with unipolar output capacitors, the output capacitor voltages of the DC-DC converters must be higher than the DC input voltage. To overcome this weakness, this paper proposes a single-phase DC-AC inverter consisting of two embedded Z-source converters with bipolar output capacitors. The proposed inverter is composed of two embedded Z-source converters with a common DC source and output AC load. Though the output capacitor voltages of the converters are relatively low compared to those of a conventional inverter, an equivalent level of AC output voltages can be obtained. Moreover, by controlling the output capacitor voltages asymmetrically, the AC output voltage of the proposed inverter can be higher than the DC input voltage. To verify the validity of the proposed inverter, experiments were performed with a DC source voltage of 38 V. By controlling the output capacitor voltages of the converters symmetrically or asymmetrically, the proposed inverter can produce sinusoidal AC output voltages. The experiments show that efficiencies of up to 95% and 97% can be achieved with the proposed inverter using symmetric and asymmetric control, respectively. PMID:25133241

  14. Review of PV Inverter Technology Cost and Performance Projections

    SciTech Connect

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  15. Inverted File Compression through Document Identifier Reassignment.

    ERIC Educational Resources Information Center

    Shieh, Wann-Yun; Chen, Tien-Fu; Shann, Jean Jyh-Jiun; Chung, Chung-Ping

    2003-01-01

    Discusses the use of inverted files in information retrieval systems and proposes a document identifier reassignment method to reduce the average gap values in an inverted file. Highlights include the d-gap technique; document similarity; heuristic algorithms; file compression; and performance evaluation from a simulation environment. (LRW)

  16. Inverted follicular keratosis successfully treated with imiquimod.

    PubMed

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  17. Inverted follicular keratosis successfully treated with imiquimod

    PubMed Central

    Karadag, Ayse Serap; Ozlu, Emin; Uzuncakmak, Tugba Kevser; Akdeniz, Necmettin; Cobanoglu, Bengu; Oman, Berkant

    2016-01-01

    Inverted follicular keratosis is a rare benign tumor of the follicular infundibulum characterized by exo-endophytic growing. It is thought to be a rare variant of the seborrheic keratosis. The diagnosis of inverted follicular keratosis is generally established histopathologically because clinical differentiation from other lesions is difficult. Herein, we present one such rare case, successfully treated with topical 5% imiquimod cream. PMID:27294052

  18. Circuit controls transients in SCR inverters

    NASA Technical Reports Server (NTRS)

    Moore, E. T.; Wilson, T. G.

    1964-01-01

    Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load.

  19. Nanostructured Inverted Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Thomas, Michael

    Organic photovoltaic cells (OPVs)are promising devices for inexpensive power generation from sunlight. Organic semiconductors, the basic materials for OPVs, can be fabricated using a broad range of fabrication technologies from vapor deposition to solution processing. Upon light absorption, a strongly bound exciton is generated which can diffuse to a donor-acceptor heterojunction. At this interface it can be dissociated into free charge carriers which can be collected by the device electrodes. A major challenge for OPVs are short exciton diffusion lengths of up to 20 nm. Morphology engineering is required in order to harvest the exciton before it recombines and improve OPV performance. This work focuses on the study of nanostructured morphologies for use in inverted architecture OPVs. Glancing angle deposition (GLAD)is employed to fabricate nanocolumnar acceptor films. Through combining these nanostructured C60 films with a conjugated polymer donor P3CBT and a small molecule 3-Q, inverted OPVs are fabricated with the goal to analyze effect of morphology engineering on device performance. A major challenge was that C60 were found to be soluble in most commonly used organic solvents such as dichlorobenzene or chloroform. Although this challenge has limited the donor choice and therefore has limited device performance, a significant effect of morphology engineering could be observed. All GLAD structured C60 OPVs outperformed state of the art architectures such as planar films and bulk heterojunctions fabricated with the same materials. For P3CBT in particular the GLAD structured devices exhibited a twofold increase in power conversion efficiency compared with bulk heterojunctions and a fourfold increase compared with planar devices. In a further study, the acceptor materials PTCDA and C60 were co-evaporated into a single film. PTCDA is stable against non-polar organic solvents while C60 provides a high electron mobility. Nanocolumnar acceptor blended PTCDA:C60 films

  20. Development of a surface micro-machined binary logic inverter for ultra-low frequency MEMS sensor applications

    NASA Astrophysics Data System (ADS)

    Chakraborty, S.; Bhattacharyya, T. K.

    2010-10-01

    This paper presents the development of surface micro-machined binary logic inverter for implementation in low-frequency signal processing applications in MEMS-based sensors. The micro-cantilever switch, which is the fundamental building block of the design, has been designed and optimized with an analytical method and validated with simulation. The working principle of the inverter has been comprehensively worked out. A thorough detail of the design and performance analysis of the inverter has been carried out and it has been verified using system level simulation. The PolyMUMPs surface micro-machining process has been used for implementing and fabricating the MEMS-based digital inverter. The mechanical response and the switching response of the beams used in the inverter have been extensively investigated. Thorough static and dynamic functional characterizations have been carried out on the inverter.

  1. Improved current control makes inverters the power sources of choice

    SciTech Connect

    Yamamoto, H.; Harada, S.; Ueyama, T.

    1997-02-01

    It is now generally understood that by increasing the operating or switching frequency of a power source the size of the main transformer and main reactor can be shrunk. Thus, a 300-A DC welding power source weighing well under 100 lb can be produced. This makes the inverter power source an ideal choice for applications requiring equipment maneuverability. It is also generally understood that due to higher switching frequencies, a smoother output is obtained from inverter power sources. In the late 1980s, the company developed a new double-inverter power source by which inverted DC weld output is inverted back to AC weld output. This product was the first of its kind in the world. Again, the small compact size of this product was of great interest. Utilizing current waveform control, it was realized that fast response switching from electrode negative to electrode positive could be accurately controlled, offering benefits such as AC GTA welding with high-frequency start only, even at a low welding current. The primary benefit is the ability to limit the electrode positive half cycle to less than 5%. The electrode positive half cycle is responsible for tungsten erosion, which also creates the balling effect of a tungsten electrode. By limiting the electrode positive portion of the AC cycle to a very low level, a rather sharp point can be maintained on the tungsten, which creates a very concentrated, focused arc column. This ability provides excellent joint penetration in fillet welding of aluminum alloys, especially on thick plate. It also reduces the heat-affected zone in AC GTA welding of aluminum.

  2. Advances in series resonant inverter technology and its effect on spacecraft employing electric propulsion

    NASA Technical Reports Server (NTRS)

    Robson, R. R.

    1982-01-01

    The efficiency of transistorized Series Resonant Inverters (SRIs), which is higher than that of silicon-controlled rectifier alternatives, reduces spacecraft radiator requirements by 40% and may eliminate the need for heat pipes on 30-cm ion thruster systems. Recently developed 10- and 25-kW inverters have potential applications in gas thrusters, and represent the first spaceborne SRI designs for such power levels. Attention is given to the design and control system approaches employed in these inverter designs to improve efficiency and reduce weight, along with the impact of such improved parameters on electric propulsion systems.

  3. Static Characteristics of the Ferroelectric Transistor Inverter

    NASA Technical Reports Server (NTRS)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  4. Inverted spectra of SWCNT films

    NASA Astrophysics Data System (ADS)

    Lehman, John; Hurst, Katherine; Roberson, Lara; Nield, Kathryn; Hamlin, John

    2008-03-01

    Diffuse Reflectance for purified single wall carbon nanotube (SWCNT) films and its relation to absorptance in the wavelength range 0.6 μm to 2 μm are inverted when compared to absorptivity data in the literature. This surprising behavior has been corroborated by diffuse reflectance measurements and shows that the reflectance is a substantial part of the unique optical behavior. Typically, the absorptance is fairly assumed to be complementary to the transmittance, while the reflectivity is insignificant. Only in certain instances (see for example, Barnes, et. al[1], Wang, et. al[2]), is the small reflectance explicitly accounted for. In the present work, we present diffuse reflectance and specular absorptance at normal incidence of SWCNT films. [1] T. M. Barnes, J. van de Lagemaat, D. Levi,1 G. Rumbles, T. J. Coutts, C. L. Weeks, D. A. Britz, I. Levitsky, J. Peltola, P. Glatkowski, Phys. Rev. B 75, 235410 (2007). [2] F. Wang, M. Y. Sfeir, L. Huang, X. M. H. Huang, Wu, J. Kim, J. Hone, S. O'Brien, L. E. Brus, T. F. Heinz, PRL 96, 167401 (2006).

  5. A SiC MOSFET Based Inverter for Wireless Power Transfer Applications

    SciTech Connect

    Onar, Omer C; Chinthavali, Madhu Sudhan; Campbell, Steven L; Ning, Puqi; White, Cliff P; Miller , John M.

    2014-01-01

    In a wireless power transfer (WPT) system, efficiency of the power conversion stages is crucial so that the WPT technology can compete with the conventional conductive charging systems. Since there are 5 or 6 power conversion stages, each stage needs to be as efficient as possible. SiC inverters are crucial in this case; they can handle high frequency operation and they can operate at relatively higher temperatures resulting in reduces cost and size for the cooling components. This study presents the detailed power module design, development, and fabrication of a SiC inverter. The proposed inverter has been tested at three center frequencies that are considered for the WPT standardization. Performance of the inverter at the same target power transfer level is analyzed along with the other system components. In addition, another SiC inverter has been built in authors laboratory by using the ORNL designed and developed SiC modules. It is shown that the inverter with ORNL packaged SiC modules performs simular to that of the inverter having commercially available SiC modules.

  6. Integrated Inverter For Driving Multiple Electric Machines

    DOEpatents

    Su, Gui-Jia [Knoxville, TN; Hsu, John S [Oak Ridge, TN

    2006-04-04

    An electric machine drive (50) has a plurality of inverters (50a, 50b) for controlling respective electric machines (57, 62), which may include a three-phase main traction machine (57) and two-phase accessory machines (62) in a hybrid or electric vehicle. The drive (50) has a common control section (53, 54) for controlling the plurality of inverters (50a, 50b) with only one microelectronic processor (54) for controlling the plurality of inverters (50a, 50b), only one gate driver circuit (53) for controlling conduction of semiconductor switches (S1-S10) in the plurality of inverters (50a, 50b), and also includes a common dc bus (70), a common dc bus filtering capacitor (C1) and a common dc bus voltage sensor (67). The electric machines (57, 62) may be synchronous machines, induction machines, or PM machines and may be operated in a motoring mode or a generating mode.

  7. Removing Barriers to Utility Interconnected Photovoltaic Inverters

    SciTech Connect

    Gonzalez, S.; Bonn, R.H.; Ginn, J.W.

    2000-10-03

    The Million Solar Roofs Initiative has motivated a renewed interest in the development of utility interconnected photovoltaic (UIPV) inverters. Government-sponsored programs (PVMaT, PVBONUS) and competition among utility interconnected inverter manufacturers have stimulated innovations and improved the performance of existing technologies. With this resurgence, Sandia National Laboratories (SNL) has developed a program to assist industry initiatives to overcome barriers to UIPV inverters. In accordance with newly adopted IEEE 929-2000, the utility interconnected PV inverters are required to cease energizing the utility grid when either a significant disturbance occurs or the utility experiences an interruption in service. Compliance with IEEE 929-2000 is being widely adopted by utilities as a minimum requirement for utility interconnection. This report summarizes work done at the SNL balance-of-systems laboratory to support the development of IEEE 929-2000 and to assist manufacturers in meeting its requirements.

  8. Base drive for paralleled inverter systems

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  9. Automatic load sharing in inverter modules

    NASA Technical Reports Server (NTRS)

    Nagano, S.

    1979-01-01

    Active feedback loads transistor equally with little power loss. Circuit is suitable for balancing modular inverters in spacecraft, computer power supplies, solar-electric power generators, and electric vehicles. Current-balancing circuit senses differences between collector current for power transistor and average value of load currents for all power transistors. Principle is effective not only in fixed duty-cycle inverters but also in converters operating at variable duty cycles.

  10. Inverted liver with suprahepatic, anteriorly displaced gallbladder.

    PubMed

    Hibbs, Harold; Ahmad, Usman

    2010-01-01

    A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

  11. Work Station For Inverting Solar Cells

    NASA Technical Reports Server (NTRS)

    Feder, H.; Frasch, W.

    1982-01-01

    Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

  12. Theoretical investigation of the oceanic inverted barometer response

    NASA Technical Reports Server (NTRS)

    Dickman, S. R.

    1988-01-01

    Dynamic tidal theory is generalized in order to predict the oceanic response to atmospheric pressure variations. The oceans are found to exhibit distinct dynamic behavior when forced at periods less than one week; depending on the harmonic type of forcing, the amplitude of the response can differ by about 20 percent or more from the static response. Even at roughly two months the traditional 'inverted barometer' may not be sufficiently accurate for applications in which detection of long-term sea level trends or vertical crustal motion is the goal. For forcing at periods of order one year the oceanic response differs by at most a few percent from the static (not the inverted barometer) response; thus calculations of meteorological excitation of the annual and Chandler wobbles can employ the static approximation without reservation.

  13. Are Archean lithospheric keels inverted?

    NASA Astrophysics Data System (ADS)

    Percival, J. A.; Pysklywec, R. N.

    2007-02-01

    Post-tectonic granite "blooms" in many Archean cratons manifest widespread crustal melting that cannot be explained by lithosphere removal, considering the long-term buoyancy of Archean cratonic keels and low mantle geotherms indicated by Archean diamondiferous lithosphere. Rather, heat may have been transferred from the mantle through a process of lithosphere inversion, driven by basal tractive forces acting on gravitationally unstable lithosphere. The top-heavy cell comprises eclogitic lower crust ( ρ = 3500 kg/m 3) lying above depleted mantle lithosphere ( ρ = 3300 kg/m 3), whose aggregate density remained less than that of surrounding asthenosphere ( ρ = 3340 kg/m 3). Parameterized numerical models of the inversion process show a > 40 m.y. pulse of maximum 1060 °C temperatures in the lower crust, sufficient to drive anhydrous melting, when overturned basal lithosphere reaches the Moho. In equilibrating to lower lithosphere conditions, the eclogitic cap may have yielded siliceous melts that infiltrated overlying, previously depleted mantle, producing the high Si/Mg characteristic of some cratonic peridotites. P-T paths calculated for the central part of the inverting cell criss-cross the graphite-diamond boundary, explaining development of large diamond crystals through numerous growth increments. The craton stabilization process follows terminal tectonism by about 50 m.y. as a result of initial cooling, eclogite formation and lithosphere stiffening. Related consequences in the crust include low-pressure regional metamorphism and widespread hydrothermal effects including some gold mineralization. Craton stability is attributed to the high strength of the depleted mantle lithosphere, its rectified density profile, and the presence of refractory compositions at the lithosphere-asthenosphere boundary.

  14. Analysis of Niemann-Pick C1-like 1 (NPC1L1) genetic polymorphisms and haplotypes in Chinese Han population.

    PubMed

    Lou, Xiao-Ya; Qin, Chong-Zhen; Bao, Mei-Hua; Hu, Dong-Li; Chen, Feng; Sun, Hong; Chen, Yao; Guo, Dong; Zhang, Wei; Cheng, Yu; Zhou, Hong-Hao

    2015-09-01

    Niemann-Pick C1-like 1 (NPC1L1i) protein is the key transporter responsible for dietary cholesterol absorption. Recent studies indicated that several functional polymorphisms of NPC1L1 were associated with coronary heart disease (CHD) and response to ezetimibe therapy. The aim of the present study was to analyze the allele frequency and haplotype distribution of NPC1L1 polymorphisms in Chinese Hans and to compare them with those of other ethnic populations reported before. Blood samples were collected from 424 unrelated Chinese Hans (246 males and 178 females). Ten NPC1L1 polymorphisms (-762T > C, -133A > G, -18C > A, 1721C > T, 1735C > G, 1764T > C, 1767G > A, 27677T > C, 25342A > C and 28650A > G) were genotyped by direct sequencing or polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Among the variants, the minor allele frequency of -762T > C and 1735C > G were 35.0% and 37.0%, respectively. Furthermore, these two polymorphisms were highly linked with a D' value of 0.80. The observed frequencies of two major haplotypes were 59.1% for T-762/C1735 and 30.1% for C-762/G1735, respectively. The frequencies of the rest variants were extremely low (1.8% for - 133G, 1.5% for -18A, 0.9% for 1721T and only 0.2% for 27677C allele, respectively) or even not detected (1764T > C, 1767G > A, 25342A > C and 28650A > G) in our study population. Comparison with other ethnic populations revealed a remarkable genetic variability in the incidences of NPC1L1 polymorphisms. The frequencies of NPC1L1 polymorphisms in Chinese Hans are comparable to Japanese population but totally different from Caucasians, African-Americans and Hispanic individuals. This is the first study to report the ethnic difference in the frequencies of NPC1L1 functional polymorphisms in detail. -762T > C and 1735C > G are two prevalent NPC1L1 variants which need further studies to explore their clinical impact on CHD prevalence and response to ezetimibe therapy in Chinese Hans

  15. Noise from Supersonic Coaxial Jets. Part 3; Inverted Velocity Profile

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.; Morris, Philip J.

    1997-01-01

    The instability wave noise generation model is used to study the instability waves in the two shear layers of an inverted velocity profile, supersonic, coaxial jet and the noise radiated from the dominant wave. The inverted velocity profile jet has a high speed outer stream surrounding a low speed inner stream and the outer shear layer is always larger than the inner shear layer. The jet mean flows are calculated numerically. The operating conditions are chosen to exemplify the effect of the coaxial jet outer shear layer initial spreading rates. Calculations are made for the stability characteristics in the coaxial jet shear layers and the noise radiated from the instability waves for different operating conditions with the same total thrust, mass flow and exit area as a single reference jet. Results for inverted velocity profile jets indicate that relative maximum instability wave amplitudes and far field peak noise levels can be reduced from that of the reference jet by having higher spreading rates for the outer shear layer, low velocity ratios, and outer streams hotter than the inner stream.

  16. EMPLACEMENT DRIFT INVERT-LOW STEEL EVALUATION

    SciTech Connect

    M. E. Taylor and D. H. Tang

    2000-09-29

    This technical report evaluates and develops options for reducing the amount of steel in the emplacement drift invert. Concepts developed in the ''Invert Configuration and Drip Shield Interface'' were evaluated to determine material properties required for the proposed invert concepts. Project requirements documents prescribe the use of a carbon steel frame for the invert with a granular material of crushed tuff as ballast. The ''Invert Configuration and Drip Shield Interface'' developed three concepts: (1) All-Ballast Invert; (2) Modified Steel Invert with Ballast; and (3) Steel Tie with Ballast Invert. Analysis of the steel frame members, runway beams, and guide beams, for the modified steel invert with ballast, decreased the quantity of steel in the emplacement drift invert, however a substantial steel support frame for the gantry and waste package/pallet assembly is still required. Use of one of the other two concepts appears to be an alternative to the steel frame and each of the concepts uses considerably less steel materials. Analysis of the steel tie with ballast invert shows that the bearing pressure on the ballast under the single steel tie, C 9 x 20, loaded with the waste package/pallet assembly, drip shield, and backfill exceeds the upper bound of the allowable bearing capacity for tuff used in this study. The single tie, C 10 x 20, will also fail for the same loading condition except for the tie length of 4.2 meters and longer. Analysis also shows that with two ties, C 9 or 10 x 20's, the average ballast pressure is less than the allowable bearing capacity. Distributing the waste package/pallet, drip shield, and backfill loads to two steel ties reduces the contact bearing pressure. Modifying the emplacement pallet end beams to a greater width, reducing the tie spacing, and increasing the width of the ties would ensure that the pallet beams are always supported by two steel ties. Further analysis is required to determine compatible tie size and spacing

  17. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification

    PubMed Central

    Brewer, Bonita J.; Payen, Celia; Di Rienzi, Sara C.; Higgins, Megan M.; Ong, Giang; Dunham, Maitreya J.; Raghuraman, M. K.

    2015-01-01

    DNA replication errors are a major driver of evolution—from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model—Origin-Dependent Inverted-Repeat Amplification (ODIRA)—proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error—the ligation of leading and lagging nascent strands to create “closed” forks—can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent—a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of

  18. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold vltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  19. Addressable inverter matrix for process and device characterization

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Sayah, H. R.

    1985-01-01

    The addressable inverter matrix consists of 222 inverters each accessible with the aid of a shift register. The structure has proven useful in characterizing the variability of inverter transfer curves and in diagnosing processing faults. For good 3-micron CMOS bulk inverters investigated in this study, the percent standard deviation of the inverter threshold voltage was less than one percent and the inverter gain (the slope of the inverter transfer curve at the inverter threshold voltage) was less than 3 percent. The average noise margin for the inverters was near 2 volts for a power supply voltage of 5 volts. The specific faults studied included undersize pull-down transistor widths and various open contacts in the matrix.

  20. An SCR inverter for electric vehicles

    NASA Technical Reports Server (NTRS)

    Latos, T.; Bosack, D.; Ehrlich, R.; Jahns, T.; Mezera, J.; Thimmesch, D.

    1980-01-01

    An inverter for an electric vehicle propulsion application has been designed and constructed to excite a polyphase induction motor from a fixed propulsion battery source. The inverter, rated at 35kW peak power, is fully regenerative and permits vehicle operation in both the forward and reverse directions. Thyristors are employed as the power switching devices arranged in a dc bus commutated topology. This paper describes the major role the controller plays in generating the motor excitation voltage and frequency to deliver performance similar to dc systems. Motoring efficiency test data for the controller are presented. It is concluded that an SCR inverter in conjunction with an ac induction motor is a viable alternative to present dc vehicle propulsion systems on the basis of performance and size criteria.

  1. DC-AC Cascaded H-Bridge Multilevel Boost Inverter With No Inductors for Electric/Hybrid Electric Vehicle Applications

    SciTech Connect

    Tolbert, Leon M; Ozpineci, Burak; Du, Zhong; Chiasson, John N

    2009-01-01

    This paper presents a cascaded H-bridge multilevel boost inverter for electric vehicle (EV) and hybrid EV (HEV) applications implemented without the use of inductors. Currently available power inverter systems for HEVs use a dc-dc boost converter to boost the battery voltage for a traditional three-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. A cascaded H-bridge multilevel boost inverter design for EV and HEV applications implemented without the use of inductors is proposed in this paper. Traditionally, each H-bridge needs a dc power supply. The proposed design uses a standard three-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the dc power source. A fundamental switching scheme is used to do modulation control and to produce a five-level phase voltage. Experiments show that the proposed dc-ac cascaded H-bridge multilevel boost inverter can output a boosted ac voltage without the use of inductors.

  2. A diagonally inverted LU implicit multigrid scheme

    NASA Technical Reports Server (NTRS)

    Yokota, Jeffrey W.; Caughey, David A.; Chima, Rodrick V.

    1988-01-01

    A new Diagonally Inverted LU Implicit scheme is developed within the framework of the multigrid method for the 3-D unsteady Euler equations. The matrix systems that are to be inverted in the LU scheme are treated by local diagonalizing transformations that decouple them into systems of scalar equations. Unlike the Diagonalized ADI method, the time accuracy of the LU scheme is not reduced since the diagonalization procedure does not destroy time conservation. Even more importantly, this diagonalization significantly reduces the computational effort required to solve the LU approximation and therefore transforms it into a more efficient method of numerically solving the 3-D Euler equations.

  3. Vigilance and task load - In search of the inverted U

    NASA Technical Reports Server (NTRS)

    Wiener, E. L.; Curry, R. E.; Faustina, M. L.

    1984-01-01

    The 'Inverted-U Hypothesis' states that for a given task, there is an optimal level of workload or demand that yields the highest level of performance. A departure in either direction will result in a monotonically lower performance level, hence an inverted-U-shaped relationship between task demand and quality of performance. Most studies to date have failed to demonstrate the left-hand branch of the curve, that is, the regime in which performance presumably rises as load increases. The purpose of this study was to explore whether low-level additional demand on the monitor would result in improved performance. Four groups of subjects performed a visual monitoring task for 48 min, then two of the four groups were given additional tasks, and a third had potentially distracting information on its display. Results indicated that the two groups with additional demand detected more signals than did the control group or the control-plus-distraction group. There were no significant differences in false alarms.

  4. High voltage series resonant inverter ion engine screen supply. [SCR series resonant inverter for space applications

    NASA Technical Reports Server (NTRS)

    Biess, J. J.; Inouye, L. Y.; Shank, J. H.

    1974-01-01

    A high-voltage, high-power LC series resonant inverter using SCRs has been developed for an Ion Engine Power Processor. The inverter operates within 200-400Vdc with a maximum output power of 2.5kW. The inverter control logic, the screen supply electrical and mechanical characteristics, the efficiency and losses in power components, regulation on the dual feedback principle, the SCR waveforms and the component weight are analyzed. Efficiency of 90.5% and weight density of 4.1kg/kW are obtained.

  5. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    1990-01-01

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  6. Inverters for interfacing of solar cells with the power grid

    NASA Astrophysics Data System (ADS)

    Karamanzanis, G. N.; Jackson, R. D.

    In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

  7. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Astrophysics Data System (ADS)

    Baumann, E. D.; Myers, I. T.; Hammoud, A. N.

    The use of a multiple pulse testing technique to determine the electrical characteristics of large megawatt-level power systems for aerospace missions is proposed. An innovative test method based on the multiple pulse technique is demonstrated on a 2-kW Mapham inverter. The concept of this technique shows that characterization of large power systems under electrical equilibrium at rated power can be accomplished without large costly power supplies. The heat generation that occurs in systems when tested in a continuous mode is eliminated. The results indicate that there is a good agreement between this testing technique and that of steady state testing.

  8. Dynamic maneuvers with a mobile inverted pendulum

    NASA Astrophysics Data System (ADS)

    Pogue, Edward

    A mobile inverted pendulum (MIP) type robot was constructed to test the feasibility of performing high speed, dynamic maneuvers. Techniques were developed for line following and to achieve high speed motion with a MIP. The results indicate that the speeds necessary for the maneuver can be achieved, and the groundwork is laid for further experimentation.

  9. Two-Stage Series-Resonant Inverter

    NASA Technical Reports Server (NTRS)

    Stuart, Thomas A.

    1994-01-01

    Two-stage inverter includes variable-frequency, voltage-regulating first stage and fixed-frequency second stage. Lightweight circuit provides regulated power and is invulnerable to output short circuits. Does not require large capacitor across ac bus, like parallel resonant designs. Particularly suitable for use in ac-power-distribution system of aircraft.

  10. Inverter Matrix for the Clementine Mission

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Tardio, G.; Soli, G. A.

    1994-01-01

    An inverter matrix test circuit was designed for the Clementine space mission and is built into the RRELAX (Radiation and Reliability Assurance Experiment). The objective is to develop a circuit that will allow the evaluation of the CMOS FETs using a lean data set in the noisy spacecraft environment.

  11. Pulse width modulation inverter with battery charger

    NASA Technical Reports Server (NTRS)

    Slicker, James M. (Inventor)

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a flyback DC-DC converter circuit for recharging the battery.

  12. A Prefix Trie Index for Inverted Files.

    ERIC Educational Resources Information Center

    Nelson, Michael J.

    1997-01-01

    Applies a prefix trie index, or trie hashing, to the problem of providing fast search times, fast load times, and fast update properties in a bibliographic or full-text retrieval system with inverted files. Statistics are given for a test database consisting of an online catalog at the University of Western Ontario. (Author/LRW)

  13. Pulse width modulation inverter with battery charger

    DOEpatents

    Slicker, James M.

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  14. The Internet and the Inverted Classroom.

    ERIC Educational Resources Information Center

    Lage, Maureen J.; Platt, Glenn

    2000-01-01

    Describes a Web site that is for an undergraduate principles of microeconomics course and a main component of "The Inverted Classroom" in which lectures take place outside of class. Explains that the Web site is divided into four sections: (1) the classroom; (2) the desk; (3) the coffee shop; and (4) the library. (CMK)

  15. APP overexpression in the absence of NPC1 exacerbates metabolism of amyloidogenic proteins of Alzheimer's disease.

    PubMed

    Maulik, Mahua; Peake, Kyle; Chung, JiYun; Wang, Yanlin; Vance, Jean E; Kar, Satyabrata

    2015-12-15

    Amyloid-β (Aβ) peptides originating from β-amyloid precursor protein (APP) are critical in Alzheimer's disease (AD). Cellular cholesterol levels/distribution can regulate production and clearance of Aβ peptides, albeit with contradictory outcomes. To better understand the relationship between cholesterol homeostasis and APP/Aβ metabolism, we have recently generated a bigenic ANPC mouse line overexpressing mutant human APP in the absence of Niemann-Pick type C-1 protein required for intracellular cholesterol transport. Using this unique bigenic ANPC mice and complementary stable N2a cells, we have examined the functional consequences of cellular cholesterol sequestration in the endosomal-lysosomal system, a major site of Aβ production, on APP/Aβ metabolism and its relation to neuronal viability. Levels of APP C-terminal fragments (α-CTF/β-CTF) and Aβ peptides, but not APP mRNA/protein or soluble APPα/APPβ, were increased in ANPC mouse brains and N2a-ANPC cells. These changes were accompanied by reduced clearance of peptides and an increased level/activity of γ-secretase, suggesting that accumulation of APP-CTFs is due to decreased turnover, whereas increased Aβ levels may result from a combination of increased production and decreased turnover. APP-CTFs and Aβ peptides were localized primarily in early-/late-endosomes and to some extent in lysosomes/autophagosomes. Cholesterol sequestration impaired endocytic-autophagic-lysosomal, but not proteasomal, clearance of APP-CTFs/Aβ peptides. Moreover, markers of oxidative stress were increased in vulnerable brain regions of ANPC mice and enhanced β-CTF/Aβ levels increased susceptibility of N2a-ANPC cells to H2O2-induced toxicity. Collectively, our results show that cellular cholesterol sequestration plays a key role in APP/Aβ metabolism and increasing neuronal vulnerability to oxidative stress in AD-related pathology. PMID:26433932

  16. View of Inverted Siphon crossing Hot Water (or White) Canyon. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Inverted Siphon crossing Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  17. Electrical characterization of a Mapham inverter using pulse testing techniques

    NASA Technical Reports Server (NTRS)

    Baumann, E. D.; Myers, I. T.; Hammond, A. N.

    1990-01-01

    Electric power requirements for aerospace missions have reached megawatt power levels. Within the next few decades, it is anticipated that a manned lunar base, interplanetary travel, and surface exploration of the Martian surface will become reality. Several research and development projects aimed at demonstrating megawatt power level converters for space applications are currently underway at the NASA Lewis Research Center. Innovative testing techniques will be required to evaluate the components and converters, when developed, at their rated power in the absence of costly power sources, loads, and cooling systems. Facilities capable of testing these components and systems at full power are available, but their use may be cost prohibitive. The use of a multiple pulse testing technique is proposed to determine the electrical characteristics of large megawatt level power systems. Characterization of a Mapham inverter is made using the proposed technique and conclusions are drawn concerning its suitability as an experimental tool to evaluate megawatt level power systems.

  18. Japanese power electronics inverter technology and its impact on the American air conditioning industry

    NASA Astrophysics Data System (ADS)

    Ushimaru, Kenji

    1990-08-01

    Since 1983, technological advances and market growth of inverter-driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries, microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices, were able to direct the development and market success of inverter-driven heat pumps. As a result, leading U.S. variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales.

  19. Japanese power electronics inverter technology and its impact on the American air conditioning industry

    SciTech Connect

    Ushimaru, Kenji.

    1990-08-01

    Since 1983, technological advances and market growth of inverter- driven variable-speed heat pumps in Japan have been dramatic. The high level of market penetration was promoted by a combination of political, economic, and trade policies in Japan. A unique environment was created in which the leading domestic industries-- microprocessor manufacturing, compressors for air conditioning and refrigerators, and power electronic devices--were able to direct the development and market success of inverter-driven heat pumps. As a result, leading US variable-speed heat pump manufacturers should expect a challenge from the Japanese producers of power devices and microprocessors. Because of the vertically-integrated production structure in Japan, in contrast to the out-sourcing culture of the United States, price competition at the component level (such as inverters, sensors, and controls) may impact the structure of the industry more severely than final product sales. 54 refs., 47 figs., 1 tab.

  20. A Soft-Switching Inverter for High-Temperature Advanced Hybrid Electric Vehicle Traction Motor Drives

    SciTech Connect

    Lai, Jason; Yu, Wensong; Sun, Pengwei; Leslie, Scott; Prusia, Duane; Arnet, Beat; Smith, Chris; Cogan, Art

    2012-03-31

    The state-of-the-art hybrid electric vehicles (HEVs) require the inverter cooling system to have a separate loop to avoid power semiconductor junction over temperatures because the engine coolant temperature of 105°C does not allow for much temperature rise in silicon devices. The proposed work is to develop an advanced soft-switching inverter that will eliminate the device switching loss and cut down the power loss so that the inverter can operate at high-temperature conditions while operating at high switching frequencies with small current ripple in low inductance based permanent magnet motors. The proposed tasks also include high-temperature packaging and thermal modeling and simulation to ensure the packaged module can operate at the desired temperature. The developed module will be integrated with the motor and vehicle controller for dynamometer and in-vehicle testing to prove its superiority. This report will describe the detailed technical design of the soft-switching inverters and their test results. The experiments were conducted both in module level for the module conduction and switching characteristics and in inverter level for its efficiency under inductive and dynamometer load conditions. The performance will be compared with the DOE original specification.

  1. Niemann-Pick disease type C1(NPC1) is involved in resistance against imatinib in the imatinib-resistant Ph+ acute lymphoblastic leukemia cell line SUP-B15/RI.

    PubMed

    Naren, Duolan; Wu, Jiahui; Gong, Yuping; Yan, Tianyou; Wang, Ke; Xu, Wenming; Yang, Xi; Shi, Fangfang; Shi, Rui

    2016-03-01

    Niemann-Pick disease type C1 (NPC1) is involved in cholesterol trafficking and may normally function as a transmembrane efflux pump. Previous studies showed that its dysfunction can lead to cholesterol and daunorubicin accumulation in the cytoplasmic endosomal/lysosomal system, lead to Niemann-Pick disease and resistance to anticancer drugs. In the present study, NPC1 was shown by microarray analysis to be more highly expressed in the Ph+ acute lymphoblastic leukemia cell line SUP-B15/RI, an imatinib-resistant variant of SUP-B15/S cells without bcr-abl gene mutation established in our lab. Further investigation revealed a defect in the functional capacity of the NPC1 protein demonstrated by filipin staining accompanied by a lower intracellular imatinib mesylate(IM) concentration by high-performance liquid chromatography in SUP-B15/RI compared with SUP-B15/S cells. Furthermore, U18666A, an inhibitor of NPC1 function, was used to block cholesterol trafficking to imitate the NPC1 defect in SUP-B15/S cells, leading to higher NPC1 expression, stronger filipin fluorescence, lower intracellular IM concentrations and greater resistance against IM. Samples from non-mutated relapsed Ph+ ALL patients also showed higher NPC1 expression compared with IM-sensitive patients. Our experiment may reveal a new mechanism of IM resistance in Ph+ ALL. PMID:26818574

  2. DC-to-AC inverter ratio failure detector

    NASA Technical Reports Server (NTRS)

    Ebersole, T. J.; Andrews, R. E.

    1975-01-01

    Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.

  3. Efficient/reliable dc-to-dc inverter circuit

    NASA Technical Reports Server (NTRS)

    Pasciutti, E. R.

    1970-01-01

    Feedback loop, which contains an inductor in series with a saturable reactor, is added to a standard inverter circuit to permit the inverter power transistors to be switched in a controlled and efficient manner. This inverter is applicable where the power source has either high or low impedance properties.

  4. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    ERIC Educational Resources Information Center

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  5. Solution-processed amorphous niobium oxide as a novel electron collection layer for inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Hamada, Keisuke; Murakami, Naoya; Tsubota, Toshiki; Ohno, Teruhisa

    2013-10-01

    Amorphous niobium oxide (NbOx) as an electron collection layer in inverted polymer solar cells was prepared by a solution process. The power conversion efficiency of inverted polymer solar cells based on a blend of poly(3-hexylthiophene) and [6,6]-phenyl C61 butyric acid methyl ester was improved to 2.22% by inserting an NbOx layer between the active layer and indium tin oxide electrode. An energy level diagram of component materials in the inverted polymer solar cell indicated that the NbOx layer works as both an electron collection layer and hole blocking layer in polymer solar cells.

  6. High-power, null-type, inverted pendulum thrust stand.

    PubMed

    Xu, Kunning G; Walker, Mitchell L R

    2009-05-01

    This article presents the theory and operation of a null-type, inverted pendulum thrust stand. The thrust stand design supports thrusters having a total mass up to 250 kg and measures thrust over a range of 1 mN to 5 N. The design uses a conventional inverted pendulum to increase sensitivity, coupled with a null-type feature to eliminate thrust alignment error due to deflection of thrust. The thrust stand position serves as the input to the null-circuit feedback control system and the output is the current to an electromagnetic actuator. Mechanical oscillations are actively damped with an electromagnetic damper. A closed-loop inclination system levels the stand while an active cooling system minimizes thermal effects. The thrust stand incorporates an in situ calibration rig. The thrust of a 3.4 kW Hall thruster is measured for thrust levels up to 230 mN. The uncertainty of the thrust measurements in this experiment is +/-0.6%, determined by examination of the hysteresis, drift of the zero offset and calibration slope variation. PMID:19485530

  7. Electronic Document Management Using Inverted Files System

    NASA Astrophysics Data System (ADS)

    Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon

    2014-03-01

    The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  8. On the uncontrollable damped triple inverted pendulum

    NASA Astrophysics Data System (ADS)

    Su, H.; Woodham, C. A.

    2003-02-01

    In this paper, the controllability of the damped triple inverted pendulum is investigated. The work is concerned with the form of the cancelling pole and zero which appear in the transfer functions of an uncontrollable system, and follows on from earlier work on the damped double inverted pendulum. The investigation considers first the cases where only one of the three arm frictions is non-zero, and then explores the cases when two of the three arm frictions are non-zero. Due to the complexity of this problem, and the difficulties with the symbolic manipulation software, exploratory numerical investigations have been carried out to facilitate the symbolic investigations, all of which are reported here.

  9. Micro-inverter solar panel mounting

    DOEpatents

    Morris, John; Gilchrist, Phillip Charles

    2016-02-02

    Processes, systems, devices, and articles of manufacture are provided. Each may include adapting micro-inverters initially configured for frame-mounting to mounting on a frameless solar panel. This securement may include using an adaptive clamp or several adaptive clamps secured to a micro-inverter or its components, and using compressive forces applied directly to the solar panel to secure the adaptive clamp and the components to the solar panel. The clamps can also include compressive spacers and safeties for managing the compressive forces exerted on the solar panels. Friction zones may also be used for managing slipping between the clamp and the solar panel during or after installation. Adjustments to the clamps may be carried out through various means and by changing the physical size of the clamps themselves.

  10. The Invertible Double of Elliptic Operators

    NASA Astrophysics Data System (ADS)

    Booss-Bavnbek, Bernhelm; Lesch, Matthias

    2009-02-01

    First, we review the Dirac operator folklore about basic analytic and geometrical properties of operators of Dirac type on compact manifolds with smooth boundary and on closed partitioned manifolds and show how these properties depend on the construction of a canonical invertible double and are related to the concept of the Calderón projection. Then we summarize a recent construction of a canonical invertible double for general first order elliptic differential operators over smooth compact manifolds with boundary. We derive a natural formula for the Calderón projection which yields a generalization of the famous Cobordism Theorem. We provide a list of assumptions to obtain a continuous variation of the Calderón projection under smooth variation of the coefficients. That yields various new spectral flow theorems. Finally, we sketch a research program for confining, respectively closing, the last remaining gaps between the geometric Dirac operator type situation and the general linear elliptic case.

  11. Maskless inverted pyramid texturization of silicon.

    PubMed

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  12. Invertible linear transformations and the Lie algebras

    NASA Astrophysics Data System (ADS)

    Zhang, Yufeng; Tam, Honwah; Guo, Fukui

    2008-07-01

    With the help of invertible linear transformations and the known Lie algebras, a way to generate new Lie algebras is given. These Lie algebras obtained have a common feature, i.e. integrable couplings of solitary hierarchies could be obtained by using them, specially, the Hamiltonian structures of them could be worked out. Some ways to construct the loop algebras of the Lie algebras are presented. It follows that some various loop algebras are given. In addition, a few new Lie algebras are explicitly constructed in terms of the classification of Lie algebras proposed by Ma Wen-Xiu, which are bases for obtaining new Lie algebras by using invertible linear transformations. Finally, some solutions of a (2 + 1)-dimensional partial-differential equation hierarchy are obtained, whose Hamiltonian form-expressions are manifested by using the quadratic-form identity.

  13. Maskless inverted pyramid texturization of silicon

    PubMed Central

    Wang, Yan; Yang, Lixia; Liu, Yaoping; Mei, Zengxia; Chen, Wei; Li, Junqiang; Liang, Huili; Kuznetsov, Andrej; Xiaolong, Du

    2015-01-01

    We discovered a technical solution of such outstanding importance that it can trigger new approaches in silicon wet etching processing and, in particular, photovoltaic cell manufacturing. The so called inverted pyramid arrays, outperforming conventional pyramid textures and black silicon because of their superior light-trapping and structure characteristics, can currently only be achieved using more complex techniques involving lithography, laser processing, etc. Importantly, our data demonstrate a feasibility of inverted pyramidal texturization of silicon by maskless Cu-nanoparticles assisted etching in Cu(NO3)2 / HF / H2O2 / H2O solutions and as such may have significant impacts on communities of fellow researchers and industrialists. PMID:26035520

  14. Cholesterol Accumulation Sequesters Rab9 and Disrupts Late Endosome Function in NPC1-deficient Cells*

    PubMed Central

    Ganley, Ian G.; Pfeffer, Suzanne R.

    2013-01-01

    Niemann-Pick type C disease is an autosomal recessive disorder that leads to massive accumulation of cholesterol and glycosphingolipids in late endosomes and lysosomes. To understand how cholesterol accumulation influences late endosome function, we investigated the effect of elevated cholesterol on Rab9-dependent export of mannose 6-phosphate receptors from this compartment. Endogenous Rab9 levels were elevated 1.8-fold in Niemann-Pick type C cells relative to wild type cells, and its half-life increased 1.6-fold, suggesting that Rab9 accumulation is caused by impaired protein turnover. Reduced Rab9 degradation was accompaniedby stabilization on endosome membranes, as shown by a reduction in the capacity of Rab9 for guanine nucleotide dissociation inhibitor-mediated extraction from Niemann-Pick type C membranes. Cholesterol appeared to stabilize Rab9 directly, as liposomes loaded with prenylated Rab9 showed decreased extractability with increasing cholesterol content. Rab9 is likely sequestered in an inactive form on Niemann-Pick type C membranes, as cation-dependent man-nose 6-phosphate receptorswere missorted to the lysosome for degradation, a process that was reversed by overexpression of GFP-tagged Rab9. In addition to using primary fibroblasts isolated from Niemann-Pick type C patients, RNA interference was utilized to recapitulate the disease phenotype in cultured cells, greatly facilitating the analysis of cholesterol accumulation and late endosome function. We conclude that cholesterol contributes directly to the sequestration of Rab9 on Niemann-Pick type C cell membranes, which in turn, disrupts mannose 6-phosphate receptor trafficking. PMID:16644737

  15. Inverter testing at Sandia National Laboratories

    SciTech Connect

    Ginn, J.W.; Bonn, R.H.; Sittler, G.

    1997-04-01

    Inverters are key building blocks of photovoltaic (PV) systems that produce ac power. The balance of systems (BOS) portion of a PV system can account for up to 50% of the system cost, and its reliable operation is essential for a successful PV system. As part of its BOS program, Sandia National Laboratories (SNL) maintains a laboratory wherein accurate electrical measurements of power systems can be made under a variety of conditions. This paper outlines the work that is done in that laboratory.

  16. Inverted colloidal quantum dot solar cells.

    PubMed

    Kim, Gi-Hwan; Walker, Bright; Kim, Hak-Beom; Kim, Jin Young; Sargent, Edward H; Park, Jongnam; Kim, Jin Young

    2014-05-28

    An inverted architecture of quantum dot solar cells is demonstrated by introducing a novel ZnO method on top of the PbS CQD film. Improvements in device characteristics stem from constructive optical interference from the ZnO layer that enhances absorption in the PbS CQD layer. Outstanding diode characteristics arising from a superior PbS/ZnO junction provide a further electronic advantage. PMID:24677118

  17. Rhenium Disulfide Depletion-Load Inverter

    NASA Astrophysics Data System (ADS)

    McClellan, Connor; Corbet, Chris; Rai, Amritesh; Movva, Hema C. P.; Tutuc, Emanuel; Banerjee, Sanjay K.

    2015-03-01

    Many semiconducting Transition Metal Dichalcogenide (TMD) materials have been effectively used to create Field-Effect Transistor (FET) devices but have yet to be used in logic designs. We constructed a depletion-load voltage inverter using ultrathin layers of Rhenium Disulfide (ReS2) as the semiconducting channel. This ReS2 inverter was fabricated on a single micromechanically-exfoliated flake of ReS2. Electron beam lithography and physical vapor deposition were used to construct Cr/Au electrical contacts, an Alumina top-gate dielectric, and metal top-gate electrodes. By using both low (Aluminum) and high (Palladium) work-function metals as two separate top-gates on a single ReS2 flake, we create a dual-gated depletion mode (D-mode) and enhancement mode (E-mode) FETs in series. Both FETs displayed current saturation in the output characteristics as a result of the FET ``pinch-off'' mechanism and On/Off current ratios of 105. Field-effect mobilities of 23 and 17 cm2V-1s-1 and subthreshold swings of 97 and 551 mV/decade were calculated for the E-mode and D-mode FETs, respectively. With a supply voltage of 1V, at low/negative input voltages the inverter output was at a high logic state of 900 mV. Conversely with high/positive input voltages, the inverter output was at a low logic state of 500 mV. The inversion of the input signal demonstrates the potential for using ReS2 in future integrated circuit designs and the versatility of depletion-load logic devices for TMD research. NRI SWAN Center and ARL STTR Program.

  18. The cholesterol-binding protein NPC2 restrains recruitment of stromal macrophage-lineage cells to early-stage lung tumours.

    PubMed

    Kamata, Tamihiro; Jin, Hong; Giblett, Susan; Patel, Bipin; Patel, Falguni; Foster, Charles; Pritchard, Catrin

    2015-09-01

    The tumour microenvironment is known to play an integral role in facilitating cancer progression at advanced stages, but its function in some pre-cancerous lesions remains elusive. We have used the (V600) (E)BRAF-driven mouse lung model that develop premalignant lesions to understand stroma-tumour interactions during pre-cancerous development. In this model, we have found that immature macrophage-lineage cells (IMCs) producing PDGFA, TGFβ and CC chemokines are recruited to the stroma of premalignant lung adenomas through CC chemokine receptor 1 (CCR1)-dependent mechanisms. Stromal IMCs promote proliferation and transcriptional alterations suggestive of epithelial-mesenchymal transition in isolated premalignant lung tumour cells ex vivo, and are required for the maintenance of early-stage lung tumours in vivo. Furthermore, we have found that IMC recruitment to the microenvironment is restrained by the cholesterol-binding protein, Niemann-Pick type C2 (NPC2). Studies on isolated cells ex vivo confirm that NPC2 is secreted from tumour cells and is taken up by IMCs wherein it suppresses secretion of the CCR1 ligand CC chemokine 6 (CCL6), at least in part by facilitating its lysosomal degradation. Together, these findings show that NPC2 secreted by premalignant lung tumours suppresses IMC recruitment to the microenvironment in a paracrine manner, thus identifying a novel target for the development of chemopreventive strategies in lung cancer. PMID:26183450

  19. FET commutated current-FED inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

    1983-01-01

    A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

  20. Sizing SiC Storage Inverters for Fast Grid Frequency Support

    SciTech Connect

    Hoke, Anderson; Bennion, Kevin; Gevorgian, Vahan; Chakraborty, Sudipta; Muljadi, Eduard

    2015-11-02

    As wind and solar displace synchronous generators whose inertia stabilizes the AC grid frequency on fast time scales, it has been proposed to use energy storage systems (ESSs) to mitigate frequency transient events. Such events require a rapid surge of power from the ESS, but they occur only rarely. The high temperature tolerance of SiC MOSFETs and diodes presents an opportunity for innovative ESS inverter designs. Herein we investigate a SiC ESS inverter design such that the SiC device ratings are obeyed during mild frequency events but are exceeded during rare, major events, for a potentially more economical inverter design. In support of this proposal we present: 1. An analysis of four years of grid frequency events in the U.S. Western Interconnection. 2. A switch-level ESS inverter simulation using SiC devices with detailed loss estimates. 3. Thermal analysis of the SiC power modules during a worst-case frequency event, showing that the modules can likely withstand the brief overcurrent. This analysis supports the conclusion that it may be advantageous for economical designs (acknowledging the increased risks) to undersize the SiC switches when designing inverters to perform active power control for grid frequency support. Such a strategy may result in SiC-based designs being more competitive with less costly silicon IGBT-based designs.

  1. An integrated technique for eliminating harmonics of multilevel inverter with unequal DC sources

    NASA Astrophysics Data System (ADS)

    Malarvizhi, M.; Gnanambal, I.

    2015-02-01

    For improving the alteration performance of multilevel inverter, selective harmonics elimination methods play a significant role. In this document, an incorporated method is suggested for removing the harmonics of multilevel inverter with uneven DC sources. The suggested incorporated method is the mixture of fuzzy logic intelligent system and particle swarm optimisation (PSO) algorithm. For generating the training information set in terms of switching angle, Fuzzy is one of the synthetic intelligent methods which apply harmonic voltage and harmonic distortion. PSO is one of the swarm intelligence-based optimisation algorithms which is employed for choosing optimal switching angle from the training data set. The suggested hybrid method is executed in MATLAB/Simulink platform. At dissimilar unequal input voltage levels, the performance of the suggested method is checked by cascade H-bridge multilevel inverter. The production of the suggested method is compared with the theoretical effects.

  2. A Novel Inductor-less DC-AC Cascaded H-bridge Multilevel Boost Inverter for Electric/Hybrid Electric Vehicle Applications

    SciTech Connect

    Du, Zhong; Ozpineci, Burak; Tolbert, Leon M; Chiasson, John N

    2007-01-01

    This paper presents an inductorless cascaded H- bridge multilevel boost inverter for EV and HEV applications. Currently available power inverter systems for HEVs use a DC- DC boost converter to boost the battery voltage for a traditional 3-phase inverter. The present HEV traction drive inverters have low power density, are expensive, and have low efficiency because they need a bulky inductor. An inductorless cascaded H-bridge multilevel boost inverter for EV and HEV applications is proposed in this paper. Traditionally, each H-bridge needs a DC power supply. The proposed inductorless cascaded H-bridge multilevel boost inverter uses a standard 3-leg inverter (one leg for each phase) and an H-bridge in series with each inverter leg which uses a capacitor as the DC power source. Fundamental switching scheme is used to do modulation control and to produce a 5-level phase voltage. Experiments show that the proposed inductorless DC-AC cascaded H-bridge multilevel boost inverter can output a boosted AC voltage.

  3. High Power Factor Control Regulating Inverter Output Power in IPM Motor Driven by Inverter System without Electrolytic Capacitor

    NASA Astrophysics Data System (ADS)

    Inazuma, Kazuya; Ohishi, Kiyoshi; Haga, Hitoshi; Sazawa, Mataki; Kondo, Seiji

    This paper presents a new high power factor control method for a single-to-three-phase power converter without an electrolytic capacitor. The circuit used in the method consists of a single-phase rectifier, a small film capacitor at DC-link, a voltage-source three-phase inverter, and an IPM motor. The inverter regulates both the velocity of the IPM motor and input current waveform. In order to obtain a power factor of unity, we propose a new control method that regulates the inverter output power. The inverter output power controller is placed between the speed controller and the q-axis current controller. The inverter power is regulated by a PI and repetitive controller. When repetitive control is applied to the inverter power controller, the phase delay of the inverter power controller is quite small. The superior performance of the proposed method is demonstrated by experimental results.

  4. Inverted (hobnail) high-grade prostatic intraepithelial neoplasia and invasive inverted pattern

    PubMed Central

    ÖZNUR, MELTEM; KOCA, SEVIM BAYKAL; YILDIZ, PELIN; BAHADIR, BURAK; BEHZATOĞLU, KEMAL

    2015-01-01

    High-grade prostatic intraepithelial neoplasia (HGPIN) is considered to be an important precursor for prostatic adenocarcinoma. The present study aimed to investigate the histological features of the uncommon inverted (hobnail) pattern of HGPIN in transrectal ultrasonographic (TRUS) prostatic needle biopsies from 13 cases. These 13 diagnosed cases of inverted HGPIN were identified out of a total of 2,034 TRUS biopsies (0.63%), obtained from patients suspected to have prostate cancer. The hobnail pattern is comprised of secretory cell nuclei, which are histologically localized at the luminal surface of the prostate gland, rather than the periphery, and exhibit reverse polarity. Histological examinations were performed and the results demonstrated that 5 of the 13 cases exhibited pure inverted histology, while HGPIN was observed to be histologically associated with other patterns in the remaining 8 patients. In addition, an association with adenocarcinoma was identified in 7 of the 13 cases. All 7 carcinomas accompanied by inverted HGPIN were conventional acinar adenocarcinoma cases; of note, for these 7 cases, the Gleason score was 7 for each. One acinar adenocarcinoma case accompanying inverted HGPIN demonstrated hobnail characteristics in large areas of the invasive component. It was observed that nuclei were proliferated in the invasive cribriform glands, which was comparable to that of inverted HGPIN, and were located on the cytoplasmic luminal surface; a similar morphology was also observed in individual glands. In conclusion, the results of the present study suggested that the hobnail HGPIN pattern may be of diagnostic importance due to its high association with adenocarcinoma and the high Gleason scores in the accompanying carcinomas. PMID:26622858

  5. Influence of the inverter characteristics on the iron losses in PWM inverter fed induction motors

    SciTech Connect

    Boglietti, A.; Ferraris, P.; Lazzari, M.; Pastorelli, M.

    1995-12-31

    In this paper the authors deal with the effects of the inverter characteristics on the iron losses increment in induction motors fed by PWM controlled converters. Laboratory tests based on no-load input power measurement were carried out and in order to avoid the influence of mechanical losses and rotor copper losses, difficult to be measured or computed, a special test bench with an unconventional test device was employed. In particular the influence of the following inverter parameters are considered: modulation index; modulation waveform; switching frequency. Complete experimental results are presented and discussed.

  6. Advanced Photovoltaic Inverter Functionality using 500 kW Power Hardware-in-Loop Complete System Laboratory Testing: Preprint

    SciTech Connect

    Mather, B. A.; Kromer, M. A.; Casey, L.

    2013-01-01

    With the increasing penetration of distribution connected photovoltaic (PV) systems, more and more PV developers and utilities are interested in easing future PV interconnection concerns by mitigating some of the impacts of PV integration using advanced PV inverter controls and functions. This paper describes the testing of a 500 kW PV inverter using Power Hardware-in-Loop (PHIL) testing techniques. The test setup is described and the results from testing the inverter in advanced functionality modes, not commonly used in currently interconnected PV systems, are presented. PV inverter operation under PHIL evaluation that emulated both the DC PV array connection and the AC distribution level grid connection are shown for constant power factor (PF) and constant reactive power (VAr) control modes. The evaluation of these modes was completed under varying degrees of modeled PV variability.

  7. Dynamics of quiet human stance: computer simulations of a triple inverted pendulum model.

    PubMed

    Günther, Michael; Wagner, Heiko

    2016-01-01

    For decades, the biomechanical description of quiet human stance has been dominated by the single inverted pendulum (SIP) paradigm. However, in the past few years, the SIP model family has been falsified as an explanatory approach. Double inverted pendulum models have recently proven to be inappropriate. Human topology with three major leg joints suggests in a natural way to examine triple inverted pendulum (TIP) models as an appropriate approach. In this study, we focused on formulating a TIP model that can synthesise stable balancing attractors based on minimalistic sensor information and actuation complexity. The simulated TIP oscillation amplitudes are realistic in vertical direction. Along with the horizontal ankle, knee and hip positions, though, all simulated joint angle amplitudes still exceed the measured ones about threefold. It is likely that they could be eventually brought down to the physiological range by using more sensor information. The TIP systems' eigenfrequency spectra come out as another major result. The eigenfrequencies spread across about 0.1 Hz...20 Hz. Our main result is that joint stiffnesses can be reduced even below statically required values by using an active hip torque balancing strategy. When reducing mono- and bi-articular stiffnesses further down to levels threatening dynamic stability, the spectra indicate a change from torus-like (stable) to strange (chaotic) attractors. Spectra of measured ground reaction forces appear to be strange-attractor-like. We would conclude that TIP models are a suitable starting point to examine more deeply the dynamic character of and the essential structural properties behind quiet human stance. Abbreviations and technical terms Inverted pendulum body exposed to gravity and pivoting in a joint around position of unstable equilibrium (operating point) SIP single inverted pendulum: one rigid body pivoting around fixation to the ground (external joint) DIP double inverted pendulum: two bodies

  8. Semi-transparent inverted organic solar cells

    NASA Astrophysics Data System (ADS)

    Schmidt, H.; Winkler, T.; Tilgner, M.; Flügge, H.; Schmale, S.; Bülow, T.; Meyer, J.; Johannes, H.-H.; Riedl, T.; Kowalsky, W.

    2009-08-01

    We will present efficient semi-transparent bulk-heterojunction [regioregular of poly(3-hexylthiophene): (6,6)-phenyl C61 butyric acid methyl ester] solar cells with an inverted device architecture. Highly transparent ZnO and TiO2 films prepared by Atomic Layer Deposition are used as cathode interlayers on top of ITO. The topanode consists of a RF-sputtered ITO layer. To avoid damage due to the plasma deposition of this layer, a sputtering buffer layer of MoO3 is used as protection. This concept allows for devices with a transmissivity higher than 60 % for wavelengths 650 nm. The thickness of the MoO3 buffer has been varied in order to study its effect on the electrical properties of the solar cell and its ability to prevent possible damage to the organic active layers upon ITO deposition. Without this buffer or for thin buffers it has been found that device performance is very poor concerning the leakage current, the fill factor, the short circuit current and the power conversion efficiencies. As a reference inverted solar cells with a metal electrode (Al) instead of the ITO-top contact are used. The variation between the PCE of top versus conventional illumination of the semi-transparent cells was also examined and will be interpreted in view of the results of the optical simulation of the dielectric device stack with and without reflection top electrode. Power conversion efficiencies of 2-3 % for the opaque inverted solar cells and 1.5-2.5 % for the semi-transparent devices were obtained under an AM1.5G illumination.

  9. Volunteer Losing Balance Wearing Inverted Glasses

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Brad McLain for the Space Biology Museum Network puts a volunteer back on balance as he tries to adjust to a world inverted by a special pair of glasses. This helps illustrate how dependent the human vestibular system is on visual cues. A volunteer is The activity was part of the Space Research and You education event held by NASA's Office of Biological and Physical Research on June 25, 2002, in Arlington, VA, to highlight the research that will be conducted on STS-107.

  10. Soft Switching SEPP High Frequency Inverter for Induction Heating

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain soft switching operation of a high frequency inverter. Its output power is regulated over a wide range using a PWM control technique by connecting an auxiliary resonant circuit to the conventional single ended push pull (SEPP) high frequency inverter for induction heating. All switching devices in the proposed inverter are operated soft switching mode. This paper describes its circuit constitution and obtained experimental results from a practical point of view.

  11. Apollo 14 inverted pigeonites - Possible samples of lunar plutonic rocks.

    NASA Technical Reports Server (NTRS)

    Papike, J. J.; Bence, A. E.

    1972-01-01

    Analysis of 'inverted pigeonites' found in Apollo 14 samples 14082 and 14083 (a polymict breccia, the 'white rock') by a combination of optical, electron probe, and single-crystal X-ray diffraction techniques. These 'inverted pigeonites' are regarded as samples of plutonic rocks that have been blasted out of the Imbrium Basin. It is also concluded that lunar pigeonites will invert to orthopyroxenes, given sufficiently slow cooling histories even in very anhydrous environments.

  12. Magnetic properties of superconductors with an inverted distribution

    SciTech Connect

    Idlis, B.G.; Kopaev, Y.V.

    1980-12-01

    A study is made of a semiconductor with an inverted distribution of quasiparticles created by external pumping. For pumping rates above a threshold value, a superconducting state may be created due to the electron--electron repulsion and such a state exhibits ideal paramagnetism rather than the Meissner effect. The fluctuation correction to the magnetic susceptibility is calculated for pumping levels below the threshold and it is shown that this correction is also paramagnetic and diverges as (..mu../sub c/-..mu..)/sup -1/2/ at the threshold (..mu.. is the chemical potential of nonequilibrium particles). The possibility of insulating pairing of nonequilibrium electrons and holes in such systems is also taken into account (for congruent Fermi surfaces) and it is shown that it does not affect the magnetic susceptibility of either the normal or superconducting phases. The transport properties of such systems are also briefly discussed.

  13. Quantum spin Hall effect in inverted type-II semiconductors.

    PubMed

    Liu, Chaoxing; Hughes, Taylor L; Qi, Xiao-Liang; Wang, Kang; Zhang, Shou-Cheng

    2008-06-13

    The quantum spin Hall (QSH) state is a topologically nontrivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells and in this Letter we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. The quantum well exhibits an "inverted" phase similar to HgTe/CdTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking are essential. Remarkably, the topological quantum phase transition between the conventional insulating state and the quantum spin Hall state can be continuously tuned by the gate voltage, enabling quantitative investigation of this novel phase transition. PMID:18643529

  14. An inverted crossover resonance aiding laser cooling of ^171Yb

    NASA Astrophysics Data System (ADS)

    McFerran, J. J.

    2016-06-01

    We observe an inverted crossover resonance in $\\pi$-driven four-level systems, where $F'-F=0,+1$. The signal is observed through saturated absorption spectroscopy of the $(6s^{2})$ $^{1}S_{0}$ $-$ $(6s6p)$ $^{3}P_{1}$ transition in $^{171}$Yb, where the nuclear spin $I=1/2$. The enhanced absorption signal is used to generate a dispersive curve for 556 nm laser frequency stabilisation and the stabilised light cools $^{171}$Yb atoms in a two-stage magneto-optical trap, achieving temperatures of 20 $\\mu$K. The Doppler-free spectroscopy scheme is further used to measure isotopic frequency shifts and hyperfine separations for the intercombination line in ytterbium.

  15. CMOS inverter design-hardened to the total dose effect

    SciTech Connect

    Roche, F.M.; Salager, L.

    1996-12-01

    This paper reports and discusses the experimental behavior of two inverter structures Rad-Hardened by Design to {sup 60}Co irradiation. The authors use the results on a set of basic circuits and transistors exposed to the same total doses as these structures to establish the effective formation conditions of the parasitic channel. Then this leakage evolution is related to the gate voltage history under irradiation. Finally, they take advantage of this intrinsic degradation property to propose a new Design Rad Hardened (DRH) cell. This structure considerably limits the Low Noise Margin degradation, helps to maintain the logic functionality with a High Output level and improves both the rad-tolerance and the static power consumption.

  16. Inverted Face Processing in Body Dysmorphic Disorder

    PubMed Central

    Feusner, Jamie D.; Moller, Hayley; Altstein, Lily; Sugar, Catherine; Bookheimer, Susan; Yoon, Joanne; Hembacher, Emily

    2010-01-01

    Individuals with body dysmorphic disorder (BDD) are preoccupied with perceived defects in appearance. Preliminary evidence suggests abnormalities in global and local visual information processing. The objective of this study was to compare global and local processing in BDD subjects and healthy controls by testing the face inversion effect, in which inverted (upside-down) faces are recognized more slowly and less accurately relative to upright faces. Eighteen medication-free subjects with BDD and 17 matched, healthy controls performed a recognition task with sets of upright and inverted faces on a computer screen that were either presented for short duration (500 msec) or long duration (5000 msec). Response time and accuracy rates were analyzed using linear and logistic mixed effects models, respectively. Results indicated that the inversion effect for response time was smaller in BDD subjects than controls during the long duration stimuli, but was not significantly different during the short duration stimuli. Inversion effect on accuracy rates did not differ significantly between groups during either of the two durations. Lesser inversion effect in BDD subjects may be due to greater detail-oriented and piecemeal processing for long duration stimuli. Similar results between groups for short duration stimuli suggest that they may be normally engaging configural and holistic processing for brief presentations. Abnormal visual information processing in BDD may contribute to distorted perception of appearance; this may not be limited to their own faces, but to others’ faces as well. PMID:20434170

  17. Dual Mode Inverter Control Test Verification

    SciTech Connect

    Bailey, J.M.

    2001-04-25

    Permanent Magnet Motors with either sinusoidal back emf (permanent magnet synchronous motor [PMSM]) or trapezoidal back emf (brushless dc motor [BDCM]) do not have the ability to alter the air gap flux density (field weakening). Since the back emf increases with speed, the system must be designed to operate with the voltage obtained at its highest speed. Oak Ridge National Laboratory's (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) has developed a dual mode inverter controller (DMIC) that overcomes this disadvantage. This report summarizes the results of tests to verify its operation. The standard PEEMRC 75 kW hard-switched inverter was modified to implement the field weakening procedure (silicon controlled rectifier enabled phase advance). A 49.5 hp motor rated at 2800 rpm was derated to a base of 400 rpm and 7.5 hp. The load developed by a Kahn Industries hydraulic dynamometer, was measured with a MCRT9-02TS Himmelstein and Company torque meter. At the base conditions a current of 212 amperes produced the 7.5 hp. Tests were run at 400, 1215, and 2424 rpm. In each run, the current was no greater than 214 amperes. The horsepower obtained in the three runs were 7.5, 9.3, and 8.12. These results verified the basic operation of the DMIC in producing a Constant Power Speed Ratios (CPSR) of six.

  18. Inverting dedevelopment: geometric singularity theory in embryology

    NASA Astrophysics Data System (ADS)

    Bookstein, Fred L.; Smith, Bradley R.

    2000-10-01

    The diffeomorphism model so useful in the biomathematics of normal morphological variability and disease is inappropriate for applications in embryogenesis, where whole coordinate patches are created out of single points. For this application we need a suitable algebra for the creation of something from nothing in a carefully organized geometry: a formalism for parameterizing discrete nondifferentiabilities of invertible functions on Rk, k $GTR 1. One easy way to begin is via the inverse of the development map - call it the dedevelopment map, the deformation backwards in time. Extrapolated, this map will inevitably have singularities at which its derivative is zero. When the dedevelopment map is inverted to face forward in time, the singularities become appropriately isolated infinities of derivative. We have recently introduced growth visualizations via extrapolations to the isolated singularities at which only one directional derivative is zero. Maps inverse to these create new coordinate patches directionally rather than radically. The most generic singularity that suits this purpose is the crease f(x,y) equals (x,x2y+y3), which has already been applied in morphometrics for the description of focal morphogenetic phenomena. We apply it to embryogenesis in the form of its analytic inverse, and demonstrate its power using a priceless new data set of mouse embryos imaged in 3D by micro-MR with voxels smaller than 100micrometers 3.

  19. Series resonance inverter with triggered vacuum gaps

    NASA Astrophysics Data System (ADS)

    Damstra, Geert C.; Zhang, X.

    1994-05-01

    Series resonance inverters based on semi-conductor switching elements are well-known and have a wide range of application, mainly for lower voltages. For high voltage application many switching elements have to be put in series to obtain sufficient blocking voltage. Voltage grinding and multiple gate control elements are needed. There is much experience with the triggered vacuum gaps as high voltage/high current single shot elements, for example in reignition circuits for synthetic circuit breaker tests. These elements have a blocking voltage of 50 - 100 kV and are triggerable by a light fiber control device. A prototype inverter has been developed that generates 0.1 Hz, 30 kV AC voltages with a flat top for tests on cables and capacitors of many micro farads fed from a low voltage supply of about 600 V. Only two TVG elements are needed to switch the resonant circuit alternatively on the positive or negative supply. The resonant circuit itself consists of the capacitance of the testobject and a high quality inductor that determines the frequency and the peak current of the voltage reversing process.

  20. Lightweight PV Inverters: Dual Bi-Directional IGBTs Modules Enables Breakthrough PV Inverter Using Current Modulation Topology

    SciTech Connect

    2012-01-30

    Solar ADEPT Project: PV inverters convert DC power generated by modules into usable AC power. IPC’s initial 30kW 94lb. PV inverter reduces the weight of comparable 30kW PV inverters by 90%—reducing the cost of materials, manufacturing, shipping, and installation. With ARPA-E support, new bi-directional silicon power switches will be developed, commercialized, and utilized in IPC’s next-generation PV inverter. With these components, IPC will produce 100kW inverters that weight less than 100lb., reducing the weight of conventional 3,000lb. 100kW inverters by more than 95%. The new power switches will cut IPC’s $/W manufacturing cost in half, as well as further reduce indirect shipping and installation costs.

  1. Performance analysis of cascaded h-bridge multilevel inverter using mixed switching frequency with various dc-link voltages

    NASA Astrophysics Data System (ADS)

    Citarsa, I. B. F.; Satiawan, I. N. W.; Wiryajati, I. K.; Supriono

    2016-01-01

    Multilevel inverters have been widely used in many applications since the technology is advantageous to increase the converter capability as well as to improve the output voltage quality. According to the applied switching frequency, multilevel modulations can be subdivided into three classes, i.e: fundamental switching frequency, high switching frequency and mixed switching frequency. This paper investigates the performance of cascaded H-bridge (CHB) multilevel inverter that is modulated using mixed switching frequency (MSF) PWM with various dc-link voltage ratios. The simulation results show the nearly sinusoidal load output voltages are successfully achieved. It is revealed that there is improvement in output voltages quality in terms of THD and low-order harmonics content. The CHB inverter that is modulated using MSF PWM with equal dc-link voltage ratio (½ Vdc: ½ Vdc) produces output voltage with the lowest low-order harmonics (less than 1% of fundamental) while the CHB inverter that is modulated using MSF PWM with un-equal dc-link voltage ratio (2/3 Vdc: 1/3 Vdc) produces a 7-level output voltage with the lowest THD (16.31%) compared to the other PWM methods. Improvement of the output voltage quality here is also in line with improvement of the number of available levels provided in the output voltage. Here only 2 cells H-bridge inverter (contain 8 switches) are needed to produce a 7- level output voltage, while in the conventional CHB inverter at least 3 cells of H-bridge inverter (contain 12 switches) are needed to produce a 7-level output voltage. Hence it is valuable in term of saving number of component.

  2. Expression levels of JNK associated with polymorphic lactotransferrin haplotypes in human nasopharyngeal carcinoma

    PubMed Central

    Luo, Gengqiu; Zhou, Yanhong; Yi, Wei; Yi, Hong

    2016-01-01

    Lactotransferrin (LTF), a member of the transferrin family, serves a role in the innate immune response and is involved in anti-inflammatory, anti-microbial and anti-tumor activity. Alterations in the LTF gene are associated with an increased incidence of cancer. The LTF gene is polymorphic, and several common alleles may be observed in the general population. Our previous study identified a lower rate of occurrence of the ‘A-G-G-T’ haplotype (constructed with rs1126477, rs1126478, rs2073495 and rs9110) in nasopharyngeal carcinoma (NPC) patients compared with controls. In the present study, in order to elucidate a possible mechanism of LTF-mediated anti-tumor activity in NPC, the protein profiles of NPC and non-tumorous nasopharyngeal epithelium tissues with/without the ‘A-G-G-T’ haplotype were constructed using LTQ Orbitrap technology. The results revealed that c-Jun N-terminal kinase 2 (JNK2) was highly expressed in NPC tissues and non-tumor nasopharyngeal epithelium tissues without the ‘A-G-G-T’ haplotype. These results were confirmed by western blot analysis. Furthermore, microRNA (miRNA) microarray analysis was conducted to investigate the differential miRNA profiles of NPC and non-tumor nasopharyngeal epithelium tissues with/without the ‘A-G-G-T’ haplotype. It was observed that hsa-miR-1256 and hsa-miR-659, which are potentially targeted to the JNK2 gene, were downregulated in NPC tissues without the ‘A-G-G-T’ haplotype. Hsa-miR-298, another miRNA potentially targeted to the JNK2 gene, was downregulated in non-tumor nasopharyngeal epithelium tissues without the ‘A-G-G-T’ haplotype. In summary, these results suggested that the expression levels of JNK2 may be associated with polymorphic LTF haplotypes in human NPC. PMID:27446399

  3. Inverter Load Rejection Over-Voltage Testing: SolarCity CRADA Task 1a Final Report

    SciTech Connect

    Nelson, A.; Hoke, A.; Chakraborty, S.; Chebahtah, J.; Wang, T.; Zimmerly, B.

    2015-02-01

    Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of electric power systems. One of the urgent areas for additional research - as identified by inverter manufacturers, installers, and utilities - is the potential for transient over-voltage from PV inverters. In one stage of a cooperative tests were repeated a total of seven times. The maximum over-voltage measured in any test did not exceed 200% of nominal, and typical over-voltage levels were significantly lower. The total voltage duration and the maximum continuous time above each threshold are presented here, as well as the time to disconnect for each test. Finally, we present a brief investigation into the effect of DC input voltage as well as a series of no-load tests. This report describes testing conducted at NREL to determine the duration and magnitude of transient over-voltages created by several commercial PV inverters during load-rejection conditions. For this work, a test plan that is currently under development by the Forum on Inverter Grid Integration Issues (FIGII) has been implemented in a custom test setup at NREL. Through a cooperative research and development agreement, NREL is working with SolarCity to address two specific types of transient overvoltage: load rejection overvoltage (LRO) and ground fault overvoltage (GFO). Additional partners in this effort include the Hawaiian Electric Companies, Northern Plains Power Technologies, and the Electric Power Research Institute.

  4. Comprehensive Evaluation of Plasma 7-Ketocholesterol and Cholestan-3β,5α,6β-Triol in an Italian Cohort of Patients Affected by Niemann-Pick Disease due to NPC1 and SMPD1 Mutations.

    PubMed

    Romanello, Milena; Zampieri, Stefania; Bortolotti, Nadia; Deroma, Laura; Sechi, Annalisa; Fiumara, Agata; Parini, Rossella; Borroni, Barbara; Brancati, Francesco; Bruni, Amalia; Russo, Cinzia V; Bordugo, Andrea; Bembi, Bruno; Dardis, Andrea

    2016-04-01

    Niemann-Pick C disease (NPCD) is a rare autosomal recessive neurovisceral disorder with a heterogeneous clinical presentation. Cholestan-3β,5α,6β-triol and 7-ketocholesterol have been proposed as biomarkers for the screening of NPCD. In this work, we assessed oxysterols levels in a cohort of Italian patients affected by NPCD and analyzed the obtained results in the context of the clinical, biochemical and molecular data. In addition, a group of patients affected by Niemann-Pick B disease (NPBD) were also analyzed. NPC patients presented levels of both oxysterols way above the cut off value, except for 5 siblings presenting the variant biochemical phenotype who displayed levels of 3β,5α,6β-triol below or just above the cut-off value; 2 of them presented also normal levels of 7-KC. Both oxysterols were extremely high in a patient presenting the neonatal systemic lethal phenotype. All NPB patients showed increased oxysterols levels. In conclusion, the reported LC-MS/MS assay provides a robust non-invasive screening tool for NPCD. However, false negative results can be obtained in patients expressing the variant biochemical phenotype. These data strengthen the concept that the results should always be interpreted in the context of the patients' clinical picture and filipin staining and/or genetic studies might still be undertaken in patients with normal levels of oxysterols if symptoms are highly suggestive of NPCD. Both oxysterols are significantly elevated in NPB patients; thus a differential diagnosis should always be performed in patients presenting isolated hepatosplenomegaly, a common clinical sign of both NPCD and NPBD. PMID:26790753

  5. View of the upper part of the Inverted Siphon showing ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of the upper part of the Inverted Siphon showing sandbox at the top of the slope before dropping into the Hot Water (or White) Canyon. Looking northeast - Childs-Irving Hydroelectric Project, Irving System, Inverted Siphon, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  6. Three-phase inverter for small high speed motors

    NASA Astrophysics Data System (ADS)

    McCormick, John A.; Valenzuela, Javier A.

    1991-07-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  7. Three-phase inverter for small high speed motors

    NASA Technical Reports Server (NTRS)

    Mccormick, John A.; Valenzuela, Javier A.

    1991-01-01

    A high-frequency three-phase inverter is being developed to drive a miniature centrifugal compressor which is a key component in a long-life space-borne cryocooler. The inverter is a unique transformer-coupled design, tailored to the low-voltage high-current characteristic of the compressor's induction motor. The design and performance demonstration of a breadboard model of the inverter are described. The cryocooler uses a reverse-Brayton cycle with turbomachines to provide 5 watt of cooling at 70 K. The design target for input power to the compressor motor is 175 watts. Line-to-neutral phase voltage waveforms to be supplied by the inverter have an amplitude of 15 volt-rms at a frequency of 8 kHz. DC power at 28 volt is supplied to the inverter. The breadboard inverter was tested with a preliminary development model of the compressor. It drove the compressor over a range of operating conditions encompassing frequencies of 5 to 9 kHz at powers of 56 to 437 watt. Inverter efficiencies, calculated from experimentally verified loss models, ranged from 89 to 95 percent over the tests. The design target on efficiency is 90 percent. The inverter was demonstrated to supply starting current adequate to overcome the starting friction of the compressor's self-acting gas bearings by a safe margin.

  8. Results of Sandia National Laboratories grid-tied inverter testing

    SciTech Connect

    Kern, G.A.; Bonn, R.H.; Ginn, J.; Gonzalez, S.

    1998-07-01

    This paper proposes a definition for a Non-Islanding Inverter. This paper also presents methods that can be used to implement such an inverter, along with references to prior work on the subject. Justification for the definition is provided on both a theoretical basis and results from tests conducted at Sandia National Laboratories and Ascension Technology, Inc.

  9. Linear control of the flywheel inverted pendulum.

    PubMed

    Olivares, Manuel; Albertos, Pedro

    2014-09-01

    The flywheel inverted pendulum is an underactuated mechanical system with a nonlinear model but admitting a linear approximation around the unstable equilibrium point in the upper position. Although underactuated systems usually require nonlinear controllers, the easy tuning and understanding of linear controllers make them more attractive for designers and final users. In a recent paper, a simple PID controller was proposed by the authors, leading to an internally unstable controlled plant. To achieve global stability, two options are developed here: first by introducing an internal stabilizing controller and second by replacing the PID controller by an observer-based state feedback control. Simulation and experimental results show the effectiveness of the design. PMID:24480638

  10. HOLLOTRON switch for megawatt lightweight space inverters

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.; Goebel, D. M.; Schumacher, R. W.

    1991-01-01

    The feasibility of satisfying the switching requirements for a megawatt ultralight inverter system using HOLLOTRON switch technology was determined. The existing experimental switch hardware was modified to investigate a coaxial HOLLOTRON switch configuration and the results were compared with those obtained for a modified linear HOLLOTRON configuration. It was concluded that scaling the HOLLOTRON switch to the current and voltage specifications required for a megawatt converter system is indeed feasible using a modified linear configuration. The experimental HOLLOTRON switch operated at parameters comparable to the scaled coaxial HOLLOTRON. However, the linear HOLLOTRON data verified the capability for meeting all the design objectives simultaneously including current density (greater than 2 A/sq cm), voltage (5 kV), switching frequency (20 kHz), switching time (300 ns), and forward voltage drop (less than or equal to 20 V). Scaling relations were determined and a preliminary design was completed for an engineering model linear HOLLOTRON switch to meet the megawatt converter system specifications.

  11. Scalar field cosmologies with inverted potentials

    NASA Astrophysics Data System (ADS)

    Boisseau, B.; Giacomini, H.; Polarski, D.

    2015-10-01

    Regular bouncing solutions in the framework of a scalar-tensor gravity model were found in a recent work. We reconsider the problem in the Einstein frame (EF) in the present work. Singularities arising at the limit of physical viability of the model in the Jordan frame (JF) are either of the Big Bang or of the Big Crunch type in the EF. As a result we obtain integrable scalar field cosmological models in general relativity (GR) with inverted double-well potentials unbounded from below which possess solutions regular in the future, tending to a de Sitter space, and starting with a Big Bang. The existence of the two fixed points for the field dynamics at late times found earlier in the JF becomes transparent in the EF.

  12. A high performance current source inverter

    SciTech Connect

    Joos, G.; Moschopoulos, G.; Ziogas, P.D.

    1993-10-01

    A recent innovation in current source inverter (CSI) drives has been the introduction of pulsewidth modulation (PWM) for the purpose of improving the quality of the load currents and voltages. However, the typical six switch CSI circuit is not compatible with all standard PWM techniques thus limiting the number of schemes that can be used. The modified CSI circuit discussed in this paper removes most of the restrictions at the ``cost`` of an extra switch. Additional advantages include faster response times through modulation index control and higher efficiency. This paper includes a detailed steady-state analysis and design procedure. The feasibility and performance of the modified CSI are verified by simulation and experimental implementation on a 5 kVA converter.

  13. Alkaline degradation of invert sugar from molasses.

    PubMed

    Yang, Byung Y; Montgomery, Rex

    2007-11-01

    Sugar beet and sugar cane molasses have been shown to be suitable starting materials for producing de-icer preparations. The sucrose in the molasses is hydrolyzed to glucose and fructose by invertase. The reducing sugars are then degraded by NaOH, the alkali being neutralized by the sugar acids produced, resulting in an increase of the ionic strength and consequently depression of the freezing point of the resulting solution. For the preparation of de-icers, the desired freezing point depression to a temperature of less than about -20 degrees C can be achieved by adjusting the amount and concentration of the alkali metal hydroxide used. The resulting products are biodegradable and eliminate the corrosive effects associated with the use of conventional chloride salts. Degradation of invert sugar by NaOH has been achieved without an external heat source. The reaction products showed the same freezing point depression as seen in the degradation products from pure glucose. PMID:17222551

  14. Highly efficient fully transparent inverted OLEDs

    NASA Astrophysics Data System (ADS)

    Meyer, J.; Winkler, T.; Hamwi, S.; Schmale, S.; Kröger, M.; Görrn, P.; Johannes, H.-H.; Riedl, T.; Lang, E.; Becker, D.; Dobbertin, T.; Kowalsky, W.

    2007-09-01

    One of the unique selling propositions of OLEDs is their potential to realize highly transparent devices over the visible spectrum. This is because organic semiconductors provide a large Stokes-Shift and low intrinsic absorption losses. Hence, new areas of applications for displays and ambient lighting become accessible, for instance, the integration of OLEDs into the windshield or the ceiling of automobiles. The main challenge in the realization of fully transparent devices is the deposition of the top electrode. ITO is commonly used as transparent bottom anode in a conventional OLED. To obtain uniform light emission over the entire viewing angle and a low series resistance, a TCO such as ITO is desirable as top contact as well. However, sputter deposition of ITO on top of organic layers causes damage induced by high energetic particles and UV radiation. We have found an efficient process to protect the organic layers against the ITO rf magnetron deposition process of ITO for an inverted OLED (IOLED). The inverted structure allows the integration of OLEDs in more powerful n-channel transistors used in active matrix backplanes. Employing the green electrophosphorescent material Ir(ppy) 3 lead to IOLED with a current efficiency of 50 cd/A and power efficiency of 24 lm/W at 100 cd/m2. The average transmittance exceeds 80 % in the visible region. The on-set voltage for light emission is lower than 3 V. In addition, by vertical stacking we achieved a very high current efficiency of more than 70 cd/A for transparent IOLED.

  15. Inverting Magnetic Data Using Parallel Processing

    NASA Astrophysics Data System (ADS)

    Connor, L. M.; Connor, C. B.

    2002-12-01

    We have collaborated to develop an innovative method for inverting magnetic data from high-resolution geomagnetic maps. Our method uses parallel computations and asynchronous communication among multiple nodes of a Beowulf cluster to produce geologically constrained 3-D models of magnetic anomalies. This modeling effort comes in response to the current revolution in gathering geophysical data. Interfacing kinematic differential GPS to magnetometers has presented geo-scientists with the daunting task of interpreting very high-resolution geomagnetic maps. Traditional methods of data interpretation, such as forward modeling, are sorely taxed. Our method manipulates a set of geologically constrained parameters to eventually build a geometric model that accurately represents the magnetic anomaly. Iterations of the code execute in parallel on multiple networked nodes via MPI, a message passing interface. Each node computes a magnetic solution at different geographical field locations based on a modeled set of geological parameters, using various forward calculations. The parameter sets are continually adjusted by the downhill simplex method. Calculated values are continually compared to the observed data using a goodness-of-fit test until all parameter sets generate the same result within a specified tolerance. A set of parameters producing an anomaly mimicking the observed anomaly is the result. By changing bounds on input parameters it is practical to quickly identify equivalent solutions. These techniques are applied to a high resolution geomagnetic data set consisting of 30,000 data points and four discrete magnetic anomalies. Data were smoothed and inverted using the parallel code. The subsurface was discretized and the depth to each unit, magnetization, and depth to the base of the entire structure were allowed to vary as independent parameters. Inversion clearly highlights volcanic features of the source rocks, including the truncated cone, crater, lava flows, and

  16. Transistorized PWM inverter-induction motor drive system

    NASA Technical Reports Server (NTRS)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  17. Evaluation of a high power inverter for potential space applications

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Lanier, J. R., Jr.

    1976-01-01

    The ADM-006 inverter discussed utilizes a unique method of using power switching circuits to produce three-phase low harmonic content voltages without any significant filtering. This method is referred to as the power center approach to inverter design and is explained briefly. The results are presented of tests performed by MSFC to evaluate inverter performance, especially when required to provide power to nonlinear loads such as half or full wave rectified loads with capacitive filtering. Test preocedures and results are described. These tests show that the power center inverter essentially met or exceeded all of claims excluding voltage regulation (3.9 percent versus specified 3.3 percent) and would be a good candidate for high power inverter applications such as may be found on Space Station, Spacelab, etc.

  18. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induced P-450 mediated arachidonic acid (AA) metabolism in chick embryo liver (CEL) occurs in parenchymal cells (PC) rather than in non-parenchymal cells (NPC)

    SciTech Connect

    Paroli, L.; Rifkind, A.B. )

    1992-02-26

    TCDD induces cytochrome P-450 mediated AA metabolism in CEL and changes the dominant metabolite(s) from {omega}-OH AA to AA epoxygenase products (EETs and EET-diols). PC and NPC from CEL were separated by differential centrifugation and characterized by morphology, immunohistochemistry and P-450 mediated xenobiotic metabolism; purities were >95%. PC and NPC, from 16 day old chick embryos treated for 5 days with TCDD or vehicle alone, were cultured for 48 hr, homogenized and incubated with ({sup 14}C)-AA {plus minus} NADPH. AA products were resolved by reverse phase HPLC. The major product in control PC, {omega}-OH AA was not significantly affected by TCDD. All of the AA metabolism was NADPH dependent. Control and TCDD treated PC had the same metabolite patterns as whole liver microsomes. Neither control nor TCDD treated NPC generated P-450 AA metabolites. Also co-culturing NPC with PC did not affect AA metabolism of either cell type. The findings indicate that TCDD-induced changes in AA metabolism are retained in culture and that hepatocytes rather than NPC effect P-450 mediated AA metabolism in both control and TCDD-induced CEL.

  19. Cholestane-3β,5α,6β-triol: high levels in Niemann-Pick type C, cerebrotendinous xanthomatosis, and lysosomal acid lipase deficiency.

    PubMed

    Pajares, Sonia; Arias, Angela; García-Villoria, Judit; Macías-Vidal, Judit; Ros, Emilio; de las Heras, Javier; Girós, Marisa; Coll, Maria J; Ribes, Antonia

    2015-10-01

    Niemann-Pick type C (NPC) is a progressive neurodegenerative disease characterized by lysosomal/endosomal accumulation of unesterified cholesterol and glycolipids. Recent studies have shown that plasma cholestane-3β,5α,6β-triol (CT) and 7-ketocholesterol (7-KC) could be potential biomarkers for the diagnosis of NPC patients. We aimed to know the sensitivity and specificity of these biomarkers for the diagnosis of NPC compared with other diseases that can potentially lead to oxysterol alterations. We studied 107 controls and 122 patients including 16 with NPC, 3 with lysosomal acid lipase (LAL) deficiency, 8 with other lysosomal diseases, 5 with galactosemia, 11 with cerebrotendinous xanthomatosis (CTX), 3 with Smith-Lemli-Opitz, 14 with peroxisomal biogenesis disorders, 19 with unspecific hepatic diseases, 13 with familial hypercholesterolemia, and 30 with neurological involvement and no evidence of an inherited metabolic disease. CT and 7-KC were analyzed by HPLC-ESI-MS/MS as mono-dimethylglycine derivatives. Levels of 7-KC were high in most of the studied diseases, whereas those of CT were only high in NPC, LAL, and CTX patients. Consequently, although CT is a sensitive biomarker of NPC disease, including those cases with doubtful filipin staining, it is not specific. 7-KC is a very unspecific biomarker. PMID:26239048

  20. Recovery from adaptation to facial identity is larger for upright than inverted faces in the human occipito-temporal cortex.

    PubMed

    Mazard, Angelique; Schiltz, Christine; Rossion, Bruno

    2006-01-01

    Human faces look more similar to each other when they are presented upside-down, leading to an increase of error rates and response times during individual face discrimination tasks. Here we used functional magnetic resonance imaging (fMRI) to test the hypothesis that this perceived similarity leads to a lower recovery from identity adaptation for inverted faces than for upright faces in face-sensitive areas of the occipito-temporal cortex. Ten subjects were presented with blocks of upright and inverted faces, with the same face identity repeated consecutively in half of the blocks, and different facial identities repeated in the other blocks. When face stimuli were presented upright, the percent signal change in the bilateral middle fusiform gyrus (MFG) was larger for different faces as compared to same faces, replicating previous observations of a recovery from facial identity adaptation in this region. However, there was no significant recovery from adaptation when different inverted faces were presented. Most interestingly, the difference in activation between upright and inverted faces increased progressively during a block when different facial identities were presented. A similar pattern of activation was found in the left middle fusiform gyrus, but was less clear-cut in bilateral face-sensitive areas of the inferior occipital cortex. These findings show that the differential level of activation to upright and inverted faces in the fusiform gyrus is mainly due to a difference in recovery from adaptation, and they explain the discrepancies in the results reported in previous fMRI studies which compared the processing of upright and inverted faces. The lack of recovery from adaptation for inverted faces in the fusiform gyrus may underlie the face inversion effect (FIE), which takes place during perceptual encoding of individual face representations. PMID:16229867

  1. A PWM transistor inverter for an ac electric vehicle drive

    NASA Technical Reports Server (NTRS)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  2. One-Cycle Controlled Single Phase UPS Inverter

    NASA Astrophysics Data System (ADS)

    Xiangli, Li; Hanhong, Qi

    A one-cycle controlled single-phase full-bridge DC-AC inverter is proposed. One-cycle control is a nonlinear control method which has fast transient response and good tracking performance. The one-cycle control immunizes the inverter against the perturbation of input dc bus and provides well system dynamic regulation with hybrid sinusoidal PWM control. The basic operational theory and control method are discussed in this paper. Finally, simulation waveforms and experimental results are given. The simulation and experimental results demonstrate the effectiveness of this control technique for inverters in UPS applications, especially when nonlinear loads must to be supplied and line has large undesirable harmonic components.

  3. Electric machine and current source inverter drive system

    DOEpatents

    Hsu, John S

    2014-06-24

    A drive system includes an electric machine and a current source inverter (CSI). This integration of an electric machine and an inverter uses the machine's field excitation coil for not only flux generation in the machine but also for the CSI inductor. This integration of the two technologies, namely the U machine motor and the CSI, opens a new chapter for the component function integration instead of the traditional integration by simply placing separate machine and inverter components in the same housing. Elimination of the CSI inductor adds to the CSI volumetric reduction of the capacitors and the elimination of PMs for the motor further improve the drive system cost, weight, and volume.

  4. An iterative method to invert the LTSn matrix

    SciTech Connect

    Cardona, A.V.; Vilhena, M.T. de

    1996-12-31

    Recently Vilhena and Barichello proposed the LTSn method to solve, analytically, the Discrete Ordinates Problem (Sn problem) in transport theory. The main feature of this method consist in the application of the Laplace transform to the set of Sn equations and solve the resulting algebraic system for the transport flux. Barichello solve the linear system containing the parameter s applying the definition of matrix invertion exploiting the structure of the LTSn matrix. In this work, it is proposed a new scheme to invert the LTSn matrix, decomposing it in blocks and recursively inverting this blocks.

  5. Skull Base Inverted Papilloma: A Comprehensive Review

    PubMed Central

    Wassef, Shafik N.; Batra, Pete S.; Barnett, Samuel

    2012-01-01

    Skull base inverted papilloma (IP) is an unusual entity for many neurosurgeons. IP is renowned for its high rate of recurrence, its ability to cause local destruction, and its association with malignancy. This paper is a comprehensive review of the reports, studies, and reviews published in the current biomedical literature from 1947 to September 2010 and synthesize this information to focus on its potential invasion to the base of the skull and possible intradural extension. The objective is to familiarize the clinician with the different aspects of this unusual disease. The role of modern diagnostic tools in medical imaging in order to assess clearly the limits of the tumors and to enhance the efficiency and the safety in the choice of a surgical approach is pointed out. The treatment guidelines for IP have undergone a complex evolution that continues today. Radical excision of the tumour is technically difficult and often incomplete. Successful management of IP requires resection of the affected mucosa which could be achieved with open surgery, endoscopic, or combined approach. Radio and chemotherapy were used for certain indications. More optimally research would be a multicenter randomized trials with large size cohorts. PMID:23346418

  6. Inverted Metamorphic Multijunction (IMM) Cell Processing Instructions

    SciTech Connect

    Duda, A.; Ward, S.; Young, M.

    2012-02-01

    This technical report details the processing schedule used to fabricate Inverted Metamorphic Multijunction (IMM) concentrator solar cells at The National Renewable Energy Laboratory (NREL). These devices are used as experimental test structures to support the research at NREL that is focused on increasing the efficiency of photovoltaic power conversion. They are not intended to be devices suitable for deployment in working concentrator systems primarily because of heat sinking issues. The process schedule was developed to be compatible with small sample sizes and to afford relatively rapid turn-around times, in support of research efforts. The report describes the use of electro deposition of gold for both the back and front contacts. Electro-deposition is used because of its rapid turn around time and because it is a benign metallization technique that is seldom responsible for damage to the semiconductors. The layer transfer technique is detailed including the use of a commercially available adhesive and the etching away of the parent gallium arsenide substrate. Photolithography is used to define front contact grids as well as the mesa area of the cell. Finally, the selective wet chemical etchant system is introduced and its use to reveal the back contact is described.

  7. Faster Processing for Inverting GPS Occultation Data

    NASA Technical Reports Server (NTRS)

    Ao, Chi

    2004-01-01

    A document outlines a computational method that can be incorporated into two prior methods used to invert Global Positioning System (GPS) occultation data [signal data acquired by a low-Earth-orbiting satellite as either this or the GPS satellite rises above or falls below the horizon] to obtain information on altitude-dependent properties of the atmosphere. The two prior inversion methods, known as back propagation and canonical transform, are computationally expensive because for each occultation, they involve numerical evaluation of a large number of diffraction-like spatial integrals. The present method involves an angular-spectrum-based phase-extrapolation approximation in which each data point is associated with a plane-wave component that propagates in a unique direction from the orbit of the receiving satellite to intersect a straight line tangent to the orbit at a nearby point. This approximation enables the use of fast Fourier transforms (FFTs), which apply only to data collected along a straight-line trajectory. The computation of the diffraction-like integrals in the angular-spectrum domain by use of FFTs takes only seconds, whereas previously, it took minutes.

  8. Inverted Leidenfrost-like Effect during Condensation.

    PubMed

    Narhe, Ramchandra; Anand, Sushant; Rykaczewski, Konrad; Medici, Marie-Gabrielle; González-Viñas, Wenceslao; Varanasi, Kripa K; Beysens, Daniel

    2015-05-19

    Water droplets condensing on solidified phase change materials such as benzene and cyclohexane near their melting point show in-plane jumping and continuous "crawling" motion. The jumping drop motion has been tentatively explained as an outcome of melting and refreezing of the materials surface beneath the droplets and can be thus considered as an inverted Leidenfrost-like effect (in the classical case vapor is generated from a droplet on a hot substrate). We present here a detailed investigation of jumping movements using high-speed imaging and static cross-sectional cryogenic focused ion beam scanning electron microscope imaging. Our results show that drop motion is induced by a thermocapillary (Marangoni) effect. The in-plane jumping motion can be delineated to occur in two stages. The first stage occurs on a millisecond time scale and comprises melting the substrate due to drop condensation. This results in droplet depinning, partial spreading, and thermocapillary movement until freezing of the cyclohexane film. The second stage occurs on a second time scale and comprises relaxation motion of the drop contact line (change in drop contact radius and contact angle) after substrate freezing. When the cyclohexane film cannot freeze, the droplet continuously glides on the surface, resulting in the crawling motion. PMID:25807004

  9. Performance of an inverted ion source

    SciTech Connect

    Salvadori, M. C.; Teixeira, F. S.; Sgubin, L. G.; Araujo, W. W. R.; Spirin, R. E.; Oks, E. M.; Brown, I. G.

    2013-02-15

    Whereas energetic ion beams are conventionally produced by extracting ions (say, positive ions) from a plasma that is held at high (positive) potential, with ion energy determined by the potential drop through which the ions fall in the beam formation electrode system, in the device described here the plasma and its electronics are held at ground potential and the ion beam is formed and injected energetically into a space maintained at high (negative) potential. We refer to this configuration as an 'inverted ion source.' This approach allows considerable savings both technologically and economically, rendering feasible some ion beam applications, in particular small-scale ion implantation, that might otherwise not be possible for many researchers and laboratories. We have developed a device of this kind utilizing a metal vapor vacuum arc plasma source, and explored its operation and beam characteristics over a range of parameter variation. The downstream beam current has been measured as a function of extraction voltage (5-35 kV), arc current (50-230 A), metal ion species (Ti, Nb, Au), and extractor grid spacing and beamlet aperture size (3, 4, and 5 mm). The downstream ion beam current as measured by a magnetically-suppressed Faraday cup was up to as high as 600 mA, and with parametric variation quite similar to that found for the more conventional metal vapor vacuum arc ion source.

  10. Direct Comparison of Inverted and Non-Inverted Growths of GaInP Solar Cells: Preprint

    SciTech Connect

    Steiner, M. A.; Geisz, J. F.; Reedy Jr, R.C.; Kurtz, S.

    2008-05-01

    The inverted growth of III-V solar cells presents some specific challenges that are not present in regular, non-inverted growths. Because the highly doped top contact layer is grown first, followed by the lengthy high-temperature growth of the remainder of the structure, there is ample time for the dopants in the contact layer to diffuse away. This leads to an increase in the contact resistance to the top layer, and a corresponding drop in voltage. The diffusion of dopants in other layers is similarly altered with respect to the non-inverted configuration because of the change in growth sequence. We compare the dopant profiles of inverted and non-inverted structures by using secondary ion mass spectroscopy and correlate the results with the observed performance of the devices. We also describe a technique for growing a GaInAsN contact layer in the inverted configuration and show that it achieves a specific contact resistance comparable to what is normally observed in non-inverted cells.

  11. Lysobisphosphatidic acid controls endosomal cholesterol levels.

    PubMed

    Chevallier, Julien; Chamoun, Zeina; Jiang, Guowei; Prestwich, Glenn; Sakai, Naomi; Matile, Stefan; Parton, Robert G; Gruenberg, Jean

    2008-10-10

    Most cell types acquire cholesterol by endocytosis of circulating low density lipoprotein, but little is known about the mechanisms of intra-endosomal cholesterol transport and about the primary cause of its aberrant accumulation in the cholesterol storage disorder Niemann-Pick type C (NPC). Here we report that lysobisphosphatidic acid (LBPA), an unconventional phospholipid that is only detected in late endosomes, regulates endosomal cholesterol levels under the control of Alix/AlP1, which is an LBPA-interacting protein involved in sorting into multivesicular endosomes. We find that Alix down-expression decreases both LBPA levels and the lumenal vesicle content of late endosomes. Cellular cholesterol levels are also decreased, presumably because the storage capacity of endosomes is affected and thus cholesterol clearance accelerated. Both lumenal membranes and cholesterol can be restored in Alix knockdown cells by exogenously added LBPA. Conversely, we also find that LBPA becomes limiting upon pathological cholesterol accumulation in NPC cells, because the addition of exogenous LBPA, but not of LBPA isoforms or analogues, partially reverts the NPC phenotype. We conclude that LBPA controls the cholesterol capacity of endosomes. PMID:18644787

  12. The mobile nucleoporin Nup2p and chromatin-bound Prp20p function in endogenous NPC-mediated transcriptional control

    PubMed Central

    Dilworth, David J.; Tackett, Alan J.; Rogers, Richard S.; Yi, Eugene C.; Christmas, Rowan H.; Smith, Jennifer J.; Siegel, Andrew F.; Chait, Brian T.; Wozniak, Richard W.; Aitchison, John D.

    2005-01-01

    Nuclear pore complexes (NPCs) govern macromolecular transport between the nucleus and cytoplasm and serve as key positional markers within the nucleus. Several protein components of yeast NPCs have been implicated in the epigenetic control of gene expression. Among these, Nup2p is unique as it transiently associates with NPCs and, when artificially tethered to DNA, can prevent the spread of transcriptional activation or repression between flanking genes, a function termed boundary activity. To understand this function of Nup2p, we investigated the interactions of Nup2p with other proteins and with DNA using immunopurifications coupled with mass spectrometry and microarray analyses. These data combined with functional assays of boundary activity and epigenetic variegation suggest that Nup2p and the Ran guanylyl-nucleotide exchange factor, Prp20p, interact at specific chromatin regions and enable the NPC to play an active role in chromatin organization by facilitating the transition of chromatin between activity states. PMID:16365162

  13. Visualization of lipid metabolism in the larval zebrafish intestine reveals a relationship between NPC1L1 mediated cholesterol uptake and dietary fatty acids

    PubMed Central

    Walters, James W.; Anderson, Jennifer L.; Bittman, Robert; Pack, Michael; Farber, Steven A.

    2012-01-01

    SUMMARY The small intestine is the primary site of dietary lipid absorption in mammals. The balance of nutrients, microorganisms, bile, and mucus that determine intestinal luminal environment cannot be recapitulated ex vivo, thus complicating studies of lipid absorption. We show that fluorescently labeled lipids can be used to visualize and study lipid absorption in live zebrafish larvae. We demonstrate that the addition of BODIPY-fatty acid to a diet high in atherogenic lipids enables imaging of enterocyte lipid droplet dynamics in real time. We find that a lipid-rich meal promotes BODIPY-cholesterol absorption into an endosomal compartment distinguishable from lipid droplets. We also show that dietary fatty acids promote intestinal cholesterol absorption by rapid relocalization of NPC1L1 to intestinal brush border. These data illustrate the power of the zebrafish system to address longstanding questions in vertebrate digestive physiology. PMID:22749558

  14. Triple inverter pierce oscillator circuit suitable for CMOS

    DOEpatents

    Wessendorf; Kurt O.

    2007-02-27

    An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a "standard" triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10 50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

  15. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    NASA Astrophysics Data System (ADS)

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Hoff, B. W.; Gilgenbach, R. M.

    2015-08-01

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  16. 8. Inverted siphon structure carrying ditch flow under Willow Creek, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. Inverted siphon structure carrying ditch flow under Willow Creek, looking southwest - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

  17. 7. Inverted siphon structure carrying ditch flow under Willow Creek, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Inverted siphon structure carrying ditch flow under Willow Creek, looking east - Natomas Ditch System, Blue Ravine Segment, Juncture of Blue Ravine & Green Valley Roads, Folsom, Sacramento County, CA

  18. 145. Credit JE. Steel section of Coleman Canal inverted siphon ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    145. Credit JE. Steel section of Coleman Canal inverted siphon #2, crossing Baldwin Creek. (JE, v. 27 1911 p. 413). - Battle Creek Hydroelectric System, Battle Creek & Tributaries, Red Bluff, Tehama County, CA

  19. Stability of Brillouin flow in planar, conventional, and inverted magnetrons

    SciTech Connect

    Simon, D. H.; Lau, Y. Y.; Greening, G.; Wong, P.; Gilgenbach, R. M.; Hoff, B. W.

    2015-08-15

    The Brillouin flow is the prevalent flow in crossed-field devices. We systematically study its stability in the conventional, planar, and inverted magnetron geometry. To investigate the intrinsic negative mass effect in Brillouin flow, we consider electrostatic modes in a nonrelativistic, smooth bore magnetron. We found that the Brillouin flow in the inverted magnetron is more unstable than that in a planar magnetron, which in turn is more unstable than that in the conventional magnetron. Thus, oscillations in the inverted magnetron may startup faster than the conventional magnetron. This result is consistent with simulations, and with the negative mass property in the inverted magnetron configuration. Inclusion of relativistic effects and electromagnetic effects does not qualitatively change these conclusions.

  20. 13. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ON THE OPERATING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  1. 15. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 2 ON THE GROUND FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  2. 14. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 1 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. WESTERN VIEW OF INVERTED BASIC OXYGEN FURNACE No. 1 ON THE OPERATING FLOOR OF THE FURNACE AISLE IN THE BOP SHOP. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  3. The Generation of an Organic Inverted Chemical Garden.

    PubMed

    Pampalakis, Georgios

    2016-05-10

    A chemical garden based on iron salt that grows in organic solvents and ions is demonstrated for the first time. This prototype chemical garden develops in an inverted orientation, thus providing evidence that downward growth is feasible. PMID:26995656

  4. Performance model for grid-connected photovoltaic inverters.

    SciTech Connect

    Boyson, William Earl; Galbraith, Gary M.; King, David L.; Gonzalez, Sigifredo

    2007-09-01

    This document provides an empirically based performance model for grid-connected photovoltaic inverters used for system performance (energy) modeling and for continuous monitoring of inverter performance during system operation. The versatility and accuracy of the model were validated for a variety of both residential and commercial size inverters. Default parameters for the model can be obtained from manufacturers specification sheets, and the accuracy of the model can be further refined using measurements from either well-instrumented field measurements in operational systems or using detailed measurements from a recognized testing laboratory. An initial database of inverter performance parameters was developed based on measurements conducted at Sandia National Laboratories and at laboratories supporting the solar programs of the California Energy Commission.

  5. Studies of the Inverted Meniscus Deposition of Silicon on Ceramic

    NASA Technical Reports Server (NTRS)

    Zook, J. D.; Grung, B.; Schuldt, S. B.; Schmit, F. M.; Heaps, J. D.

    1983-01-01

    Controlled temperature profiles essential to production of solar cells. Studies of inverted meniscus process for depositing silicon coatings on ceramic substrates described in new report. When fully developed, processed used to manufacture low-cost solar photovoltaic cells.

  6. 2. DETAIL OF INVERTED MINE CARS, LOOKING SOUTHWEST; NOTE SHORT ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. DETAIL OF INVERTED MINE CARS, LOOKING SOUTHWEST; NOTE SHORT WHEEL BASE NEEDED FOR DUMPING CONTENTS - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  7. Applying the min-projection strategy to improve the transient performance of the three-phase grid-connected inverter.

    PubMed

    Baygi, Mahdi Oloumi; Ghazi, Reza; Monfared, Mohammad

    2014-07-01

    Applying the min-projection strategy (MPS) to a three-phase grid-connected inverter to improve its transient performance is the main objective of this paper. For this purpose, the inverter is first modeled as a switched linear system. Then, the feasibility of the MPS technique is investigated and the stability criterion is derived. Hereafter, the fundamental equations of the MPS for the control of the inverter are obtained. The proposed scheme is simulated in PSCAD/EMTDC environment. The validity of the MPS approach is confirmed by comparing the obtained results with those of VOC method. The results demonstrate that the proposed method despite its simplicity provides an excellent transient performance, fully decoupled control of active and reactive powers, acceptable THD level and a reasonable switching frequency. PMID:24929629

  8. Transient effects in application of PWM inverters to induction motors

    SciTech Connect

    Persson, E. )

    1992-10-01

    Standard squirrel cage induction (SCI) motors are subjected to nonsinusoidal waveshapes when supplied form adjustable-frequency inverters. In addition to causing increased heating, these wave patterns can be destructive to the insulation. In particular, pulse width modulated (PWM) inverter output amplitudes and rise times are investigated. Motor insulation capabilities are discussed. In this paper, voltage reflections are simulated for various cable lengths and rise times and are presented graphically. Simulations confirm potential problems with long cables and short rise times.

  9. SEPP-ZVS High Frequency Inverter Incorporating Auxiliary Switch

    NASA Astrophysics Data System (ADS)

    Ogiwara, Hiroyuki; Itoi, Misao; Nakaoka, Mutsuo

    This paper presents a novel circuit topology to attain ZVS operation of a high frequency inverter over a wide range output power regulation using a PWM control technique by connecting an auxiliary switch to the conventional single ended push-pull (SEPP) ZVS high frequency inverter. A switching current is injected into the main switches via the auxiliary switch only during the short period between its turn-on and off times to supply a current required for its ZVS operation.

  10. High-performance inverters for grid-connected PV applications

    SciTech Connect

    Heide, F.J. ter; Wanner, J.

    1994-12-31

    In a few years time Mastervolt has become one of the leading European manufacturers of stand-alone inverters for marine and mobile applications. The application of photovoltaics in this area is well on its way. Based on this experience the development of grid-connected inverters evolved naturally within the context of the effort for development of grid-connected photovoltaic systems in the Netherlands. Technical description and applications are given for the Sunmaster 1800 and 300.

  11. Adaptive Selective Harmonic Minimization Based on ANNs for Cascade Multilevel Inverters With Varying DC Sources

    SciTech Connect

    Filho, Faete; Maia, Helder Z; Mateus, Tiago Henrique D; Ozpineci, Burak; Tolbert, Leon M; Pinto, Joao Onofre P

    2013-01-01

    A new approach for modulation of an 11-level cascade multilevel inverter using selective harmonic elimination is presented in this paper. The dc sources feeding the multilevel inverter are considered to be varying in time, and the switching angles are adapted to the dc source variation. This method uses genetic algorithms to obtain switching angles offline for different dc source values. Then, artificial neural networks are used to determine the switching angles that correspond to the real-time values of the dc sources for each phase. This implies that each one of the dc sources of this topology can have different values at any time, but the output fundamental voltage will stay constant and the harmonic content will still meet the specifications. The modulating switching angles are updated at each cycle of the output fundamental voltage. This paper gives details on the method in addition to simulation and experimental results.

  12. The discrete model of the power stage of the voltage source inverter for UPS

    NASA Astrophysics Data System (ADS)

    Rymarski, Zbigniew

    2011-10-01

    This article presents a new generalised discrete model of the power stage of single- and three-phase inverters including the calculations of the output filter parameters that provide an acceptable level of output voltage harmonics. The presented model can be used with the pole placement control methods such as the coefficient diagram method or the deadbeat one sampling ahead preview control. Discrete modelling of the power stage including properties of the PWM modulator makes an easy description of the chosen control law that can be directly implemented in the control software possible. The final simulation and the experimental verification of the poles placement methods in the voltage source inventer control confirm the usefulness of the presented model but some differences between the control theory and the inverter measurements are expected.

  13. Development of a rotary power transformer and inverter drive for spacecraft

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.; Bridgeforth, A. O.

    1983-01-01

    Many future satellites and spacecraft with spun and despun configurations will require the transfer of power across rotating interfaces in lieu of slip-rings and/or flexures. This is particularly true of spacecraft that have to demonstrate a long life expectancy. The rotary transformer has the desirable characteristics of high reliability and low noise, which qualify it as a potential replacement for slip rings. Development of a rotary power transformer follows the successful completion of a task to develop rotary signal-level transformers for the Galileo Spacecraft Project. The physical configuration of a rotary power transformer has a significant effect on its magnetic and electrical characteristics and therefore impacts the design of the dc/ac inverter driver. Important characteristics addressed during this development effort include: operating frequency, efficiency, transformer gap size, leakage inductance, and leakage flux. A breadboard inverter and rotary transformer were designed, fabricated and tested.

  14. Module failure isolation circuit for paralleled inverters. [preventing system failure during power conditioning for spacecraft applications

    NASA Technical Reports Server (NTRS)

    Nagano, S. (Inventor)

    1979-01-01

    A module failure isolation circuit is described which senses and averages the collector current of each paralled inverter power transistor and compares the collector current of each power transistor the average collector current of all power transistors to determine when the sensed collector current of a power transistor in any one inverter falls below a predetermined ratio of the average collector current. The module associated with any transistor that fails to maintain a current level above the predetermined radio of the average collector current is then shut off. A separate circuit detects when there is no load, or a light load, to inhibit operation of the isolation circuit during no load or light load conditions.

  15. Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint

    SciTech Connect

    Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.

    2013-03-01

    Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

  16. A novel double gate metal source/drain Schottky MOSFET as an inverter

    NASA Astrophysics Data System (ADS)

    Loan, Sajad A.; Kumar, Sunil; Alamoud, Abdulrahman M.

    2016-03-01

    In this work, we propose and simulate a novel structure of a double gate metal source/drain (MSD) Schottky MOSFET. The novelty of the proposed device is that it realizes a complete CMOS inverter action, which is actually being realized by the combination of two n and p type MOS transistors in the conventional CMOS technology. Therefore, the use of this device will significantly reduce the transistor count in implementing combinational and sequential circuits. Further, there is a significant reduction in the number of junctions and regions in the proposed device in comparison to the conventional CMOS inverter. Therefore, the proposed device is compact and can consume less power. The proposed device has been named as Sajad-Sunil-Schottky (SSS) device. The mixed mode circuit analysis of the proposed SSS device has shown that a CMOS inverter action with high logic level (VOH) and low logic level (VOL) as ∼VDD and ∼ground respectively. A two dimensional calibrated simulation study using the experimental data has revealed that the proposed SSS device in n and p type modes have subthreshold slopes (S) of 130 mV/decade and 85 mV/decade respectively and have reasonable high ION and ION/IOFF ratio's. Furthermore, it has been proved that such a device action cannot be realised by folding the conventional doped n and p MOS transistors.

  17. ConfChem Conference on Flipped Classroom: Improving Student Engagement in Organic Chemistry Using the Inverted Classroom Model

    ERIC Educational Resources Information Center

    Rossi, Robert D.

    2015-01-01

    Improving student engagement in STEM (science, technology, engineering, and mathematics) courses generally, and organic chemistry specifically, has long been a goal for educators. Recently educators at all academic levels have been exploring the "inverted classroom" or "flipped classroom" pedagogical model for improving student…

  18. Distortion and regulation characterization of a Mapham inverter

    NASA Technical Reports Server (NTRS)

    Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

    1989-01-01

    Output-voltage total harmonic distortion (THD) of a 20-kHz, 6-kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f(s)/f(r), using the EASY5 Engineering Analysis System. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f(s)/f(r) is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output-voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different from the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

  19. Distortion and regulation characterization of a Mapham inverter

    NASA Technical Reports Server (NTRS)

    Sundberg, Richard C.; Brush, Andrew S.; Button, Robert M.; Patterson, Alexander G.

    1989-01-01

    Output voltage Total Harmonic Distortion (THD) of a 20kHz, 6kVA Mapham resonant inverter is characterized as a function of its switching-to-resonant frequency ratio, f sub s/f sub r, using the EASY5 engineering analysis system. EASY5 circuit simulation results are compared with hardware test results to verify the accuracy of the simulations. The effects of load on the THD versus f sub s/f sub r ratio is investigated for resistive, leading, and lagging power factor load impedances. The effect of the series output capacitor on the Mapham inverter output voltage distortion and inherent load regulation is characterized under loads of various power factors and magnitudes. An optimum series capacitor value which improves the inherent load regulation to better than 3 percent is identified. The optimum series capacitor value is different than the value predicted from a modeled frequency domain analysis. An explanation is proposed which takes into account the conduction overlap in the inductor pairs during steady-state inverter operation, which decreases the effective inductance of a Mapham inverter. A fault protection and current limit method is discussed which allows the Mapham inverter to operate into a short circuit, even when the inverter resonant circuit becomes overdamped.

  20. Management and treatment of sinonasal inverted papilloma

    PubMed Central

    Ungari, Claudio; Riccardi, Emiliano; Reale, Gabriele; Agrillo, Alessandro; Rinna, Claudio; Mitro, Valeria; Filiaci, Fabio

    2015-01-01

    Summary Aims The aim of this paper is to describe the surgical experience of 35 patients with Inverted Papilloma (IP) of paranasal sinuses and its recurrence rate after a year of follow-up. Materials A retrospective chart review was performed on patients presenting with IP of paranasal sinuses. Thirty-five patients comprised the focus of this study. For all patients was performed a pre-surgery TC, and for more 5 patients it was necessary to perform a Magnetic Resonance (MR) with gadolinium. Results Among 35 patients selected, 18 patients underwent to open surgery, 4 patients had a combined approach with endoscopy and open surgery, while 13 patients were managed only with an endoscopic approach, with a minimum of 1 year of follow-up. Our results highlighted that the global percentage of success 12 months after the treatment was 93% and it not vary according to the tipology of the approach used if a radical excision of the lesion is achieved. More in depth, among 35 cases, only 2 patients were found to have recurrences and were treated with coronal and endoscopic approach. Conclusion It is fundamental to underline that surgery must be carried on in a radical manner to treat these tend to recur. A complete removal of the lesion and bone peripheral border filing are essential to perform a correct and definitive treatment. Also, endoscopic approach can be taken into account when tumors are localized median to a sagittal plan crossing the orbit median wall and when they did not massively compromised paranasal sinus walls. PMID:26941894

  1. Quantum Spin Hall Effect in Inverted Type II Semiconductors

    SciTech Connect

    Liu, Chaoxing; Hughes, Taylor L.; Qi, Xiao-Liang; Wang, Kang; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    The quantum spin Hall (QSH) state is a topologically non-trivial state of quantum matter which preserves time-reversal symmetry; it has an energy gap in the bulk, but topologically robust gapless states at the edge. Recently, this novel effect has been predicted and observed in HgTe quantum wells. In this work we predict a similar effect arising in Type-II semiconductor quantum wells made from InAs/GaSb/AlSb. Because of a rare band alignment the quantum well band structure exhibits an 'inverted' phase similar to CdTe/HgTe quantum wells, which is a QSH state when the Fermi level lies inside the gap. Due to the asymmetric structure of this quantum well, the effects of inversion symmetry breaking and inter-layer charge transfer are essential. By standard self-consistent calculations, we show that the QSH state persists when these corrections are included, and a quantum phase transition between the normal insulator and the QSH phase can be electrically tuned by the gate voltage.

  2. Frequency domain model for analysis of paralleled, series-output-connected Mapham inverters

    NASA Technical Reports Server (NTRS)

    Brush, Andrew S.; Sundberg, Richard C.; Button, Robert M.

    1989-01-01

    The Mapham resonant inverter is characterized as a two-port network driven by a selected periodic voltage. The two-port model is then used to model a pair of Mapham inverters connected in series and employing phasor voltage regulation. It is shown that the model is useful for predicting power output in paralleled inverter units, and for predicting harmonic current output of inverter pairs, using standard power flow techniques. Some sample results are compared to data obtained from testing hardware inverters.

  3. Frequency domain model for analysis of paralleled, series-output-connected Mapham inverters

    NASA Technical Reports Server (NTRS)

    Brush, Andrew S.; Sundberg, Richard C.; Button, Robert M.

    1989-01-01

    The Mapham resonant inverter is characterized as a two-port network driven by a selected periodic voltage. The two-port model is then used to model a pair of Mapham inverters connected in series and employing phasor voltage regulation. It is shown that the model is useful for predicting power output in paralleled inverter units, and for predicting harmonic current output of inverter pairs, using standard power flow techniques. Some examples are compared to data obtained from testing hardware inverters.

  4. Breaking Barriers to Low-Cost Modular Inverter Production & Use

    SciTech Connect

    Bogdan Borowy; Leo Casey; Jerry Foshage; Steve Nichols; Jim Perkinson

    2005-05-31

    The goal of this cost share contract is to advance key technologies to reduce size, weight and cost while enhancing performance and reliability of Modular Inverter Product for Distributed Energy Resources (DER). Efforts address technology development to meet technical needs of DER market protection, isolation, reliability, and quality. Program activities build on SatCon Technology Corporation inverter experience (e.g., AIPM, Starsine, PowerGate) for Photovoltaic, Fuel Cell, Energy Storage applications. Efforts focused four technical areas, Capacitors, Cooling, Voltage Sensing and Control of Parallel Inverters. Capacitor efforts developed a hybrid capacitor approach for conditioning SatCon's AIPM unit supply voltages by incorporating several types and sizes to store energy and filter at high, medium and low frequencies while minimizing parasitics (ESR and ESL). Cooling efforts converted the liquid cooled AIPM module to an air-cooled unit using augmented fin, impingement flow cooling. Voltage sensing efforts successfully modified the existing AIPM sensor board to allow several, application dependent configurations and enabling voltage sensor galvanic isolation. Parallel inverter control efforts realized a reliable technique to control individual inverters, connected in a parallel configuration, without a communication link. Individual inverter currents, AC and DC, were balanced in the paralleled modules by introducing a delay to the individual PWM gate pulses. The load current sharing is robust and independent of load types (i.e., linear and nonlinear, resistive and/or inductive). It is a simple yet powerful method for paralleling both individual devices dramatically improves reliability and fault tolerance of parallel inverter power systems. A patent application has been made based on this control technology.

  5. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    SciTech Connect

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is also proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.

  6. Cryogenic temperature dependence of the voltage transfer characteristics of CMOS inverters

    NASA Astrophysics Data System (ADS)

    Deen, M. J.

    1988-08-01

    The voltage transfer characteristics of CMOS inverters have been studied in detail as a function of temperature between 77 and 300 K and supply voltages between 2 and 20 V. The logic levels, maximum gain, unity gain points, noise margins and other parameters, such as ( VH - VL), all showed a marked improvement as the temperature was lowered. In particular, for one inverter with a supply of 5 V, the maximum gain increased from 57 to 105, ( VIH - VIL) decreased from 0.50 to 0.28 V and ( VH - VL) increased from 4.46 to 4.75 V on decreasing the temperature from 300 to 77 K. For all the inverters, these and other parameters showed a smooth monotonic improvement as the temperature was lowered. These and the other results obtained can be qualitatively explained as due to an increase in the absolute values in the threshold voltages of the PMOS and NMOS transistors and to an increase in the carrier mobility as the temperature was lowered.

  7. Modular Cascaded H-Bridge Multilevel PV Inverter with Distributed MPPT for Grid-Connected Applications

    DOE PAGESBeta

    Xiao, Bailu; Hang, Lijun; Mei, Jun; Riley, Cameron; Tolbert, Leon M.; Ozpineci, Burak

    2014-09-04

    This paper presents a modular cascaded H-bridge multilevel photovoltaic (PV) inverter for single- or three-phase grid-connected applications. The modular cascaded multilevel topology helps to improve the efficiency and flexibility of PV systems. To realize better utilization of PV modules and maximize the solar energy extraction, a distributed maximum power point tracking (MPPT) control scheme is applied to both single-phase and three-phase multilevel inverters, which allows the independent control of each dc-link voltage. For three-phase grid-connected applications, PV mismatches may introduce unbalanced supplied power, leading to unbalanced grid current. To solve this issue, a control scheme with modulation compensation is alsomore » proposed. An experimental three-phase 7-level cascaded H-bridge inverter has been built utilizing 9 H-bridge modules (3 modules per phase). Each H-bridge module is connected to a 185 W solar panel. Simulation and experimental results are presented to verify the feasibility of the proposed approach.« less

  8. Determination of the number of cells in a stepped sine wave inverter for equal charge transfer

    NASA Astrophysics Data System (ADS)

    Appelbaum, J.; Gabbay, D.

    1985-07-01

    The synthesis of an inverter sine wave output voltage by a staircase wave shape of low level voltage sources (cells) is accomplished by combining the cells in series at specific time intervals. Different cells of the inverter are then connected to the load for different time durations which results in unequal discharging of the cells. In order for the cells to transfer equal charge during the system operation, each voltage step should consist of a different number of cells in a parallel combination (module), the number of which depends on the time along the wave shape. The number of cells in each module is determined from the circuit current analysis and the appropriate switching time intervals, and is performed for a resistive and an inductive load. This number depends on the number of inverter voltage steps, the cell internal resistance, and the type of the load. The proper number of cells in the modules ensures identical state of charge of the cells, and equal cell recharging, and simplifies cell inspection, maintenance, and replacement.

  9. Transfer zones and fault reactivation in inverted rift basins: Insights from physical modelling

    NASA Astrophysics Data System (ADS)

    Konstantinovskaya, Elena A.; Harris, Lyal B.; Poulin, Jimmy; Ivanov, Gennady M.

    2007-08-01

    Lateral transfer zones of deformation and fault reactivation were investigated in multilayered silicone-sand models during extension and subsequent co-axial shortening. Model materials were selected to meet similarity criteria and to be distinguished on CT scans; this approach permitted non-destructive visualisation of the progressive evolution of structures. Transfer zones were initiated by an orthogonal offset in the geometry of a basal mobile aluminium sheet and/or by variations of layer thickness or material rheology in basal layers. Transfer zones affected rift propagation and fault kinematics in models. Propagation and overlapping rift culminations occurred in transfer zones during extension. During shortening, deviation in the orientation of frontal thrusts and fold axes occurred within transfer zones in brittle and ductile layers, respectively. CT scans showed that steep (58-67°) rift-margin normal faults were reactivated as reverse faults. The reactivated faults rotated to shallower dips (19-38°) with continuing shortening after 100% inversion. Rotation of rift phase faults appears to be due to deep level folding and uplift during the inversion phase. New thrust faults with shallow dips (20-34°) formed outside the inverted graben at late stages of shortening. Frontal ramps propagated laterally past the transfer structure during shortening. During inversion, the layers filling the rift structures underwent lateral compression at the depth, the graben fill was pushed up and outwards creating local extension near the surface. Sand marker layers in inverted graben have showed fold-like structures or rotation and tilting in the rifts and on the rift margins. The results of our experiments conform well to natural examples of inverted graben. Inverted rift basins are structurally complex and often difficult to interpret in seismic data. The models may help to unravel the structure and evolution of these systems, leading to improved hydrocarbon exploration

  10. From Widely Accepted Concepts in Coordination Chemistry to Inverted Ligand Fields.

    PubMed

    Hoffmann, Roald; Alvarez, Santiago; Mealli, Carlo; Falceto, Andrés; Cahill, Thomas J; Zeng, Tao; Manca, Gabriele

    2016-07-27

    We begin with a brief historical review of the development of our understanding of the normal ordering of nd orbitals of a transition metal interacting with ligands, the most common cases being three below two in an octahedral environment, two below three in tetrahedral coordination, and four below one in a square-planar environment. From the molecular orbital construction of these ligand field splittings evolves a strategy for inverting the normal order: the obvious way to achieve this is to raise the ligand levels above the metal d's; that is, make the ligands better Lewis bases. However, things are not so simple, for such metal/ligand level placement may lead to redox processes. For 18-electron octahedral complexes one can create the inverted situation, but it manifests itself in the makeup of valence orbitals (are they mainly on metal or ligands?) rather than energy. One can also see the effect, in small ways, in tetrahedral Zn(II) complexes. We construct several examples of inverted ligand field systems with a hypothetical but not unrealistic AlCH3 ligand and sketch the consequences of inversion on reactivity. Special attention is paid to the square-planar case, exemplified by [Cu(CF3)4](-), in which Snyder had the foresight to see a case of an inverted field, with the empty valence orbital being primarily ligand centered, the dx2-y2 orbital heavily occupied, in what would normally be called a Cu(III) complex. For [Cu(CF3)4](-) we provide theoretical evidence from electron distributions, geometry of the ligands, thermochemistry of molecule formation, and the energetics of abstraction of a CF3 ligand by a base, all consistent with oxidation of the ligands in this molecule. In [Cu(CF3)4](-), and perhaps more complexes on the right side of the transition series than one has imagined, some ligands are σ-noninnocent. Exploration of inverted ligand fields helps us see the continuous, borderless transition from transition metal to main group bonding. We also give

  11. Single junction inverted polymer solar cell reaching power conversion efficiency 10.31% by employing dual-doped zinc oxide nano-film as cathode interlayer.

    PubMed

    Liao, Sih-Hao; Jhuo, Hong-Jyun; Yeh, Po-Nan; Cheng, Yu-Shan; Li, Yi-Lun; Lee, Yu-Hsuan; Sharma, Sunil; Chen, Show-An

    2014-01-01

    We present high efficiency and stable inverted PSCs (i-PSC) by employing sol-gel processed simultaneously doped ZnO by Indium and fullerene derivative (BisNPC60-OH) (denoted as InZnO-BisC60) film as cathode interlayer and PTB7-Th:PC71BM as the active layer (where PTB7-Th is a low bandgap polymer we proposed previously). This dual-doped ZnO, InZnO-BisC60, film shows dual and opposite gradient dopant concentration profiles, being rich in fullerene derivative at the cathode surface in contact with active layer and rich in In at the cathode surface in contact with the ITO surface. Such doping in ZnO not only gives improved surface conductivity by a factor of 270 (from 0.015 to 4.06 S cm(-1)) but also provides enhanced electron mobility by a factor of 132 (from 8.25*10(-5) to 1.09*10(-2) cm(2) V(-1) s(-1)). The resulting i-PSC exhibits the improved PCE 10.31% relative to that with ZnO without doping 8.25%. This PCE 10.31% is the best result among the reported values so far for single junction PSC. PMID:25351472

  12. Single Junction Inverted Polymer Solar Cell Reaching Power Conversion Efficiency 10.31% by Employing Dual-Doped Zinc Oxide Nano-Film as Cathode Interlayer

    NASA Astrophysics Data System (ADS)

    Liao, Sih-Hao; Jhuo, Hong-Jyun; Yeh, Po-Nan; Cheng, Yu-Shan; Li, Yi-Lun; Lee, Yu-Hsuan; Sharma, Sunil; Chen, Show-An

    2014-10-01

    We present high efficiency and stable inverted PSCs (i-PSC) by employing sol-gel processed simultaneously doped ZnO by Indium and fullerene derivative (BisNPC60-OH) (denoted as InZnO-BisC60) film as cathode interlayer and PTB7-Th:PC71BM as the active layer (where PTB7-Th is a low bandgap polymer we proposed previously). This dual-doped ZnO, InZnO-BisC60, film shows dual and opposite gradient dopant concentration profiles, being rich in fullerene derivative at the cathode surface in contact with active layer and rich in In at the cathode surface in contact with the ITO surface. Such doping in ZnO not only gives improved surface conductivity by a factor of 270 (from 0.015 to 4.06 S cm-1) but also provides enhanced electron mobility by a factor of 132 (from 8.25*10-5 to 1.09*10-2 cm2 V-1 s-1). The resulting i-PSC exhibits the improved PCE 10.31% relative to that with ZnO without doping 8.25%. This PCE 10.31% is the best result among the reported values so far for single junction PSC.

  13. Single Junction Inverted Polymer Solar Cell Reaching Power Conversion Efficiency 10.31% by Employing Dual-Doped Zinc Oxide Nano-Film as Cathode Interlayer

    PubMed Central

    Liao, Sih-Hao; Jhuo, Hong-Jyun; Yeh, Po-Nan; Cheng, Yu-Shan; Li, Yi-Lun; Lee, Yu-Hsuan; Sharma, Sunil; Chen, Show-An

    2014-01-01

    We present high efficiency and stable inverted PSCs (i-PSC) by employing sol-gel processed simultaneously doped ZnO by Indium and fullerene derivative (BisNPC60-OH) (denoted as InZnO-BisC60) film as cathode interlayer and PTB7-Th:PC71BM as the active layer (where PTB7-Th is a low bandgap polymer we proposed previously). This dual-doped ZnO, InZnO-BisC60, film shows dual and opposite gradient dopant concentration profiles, being rich in fullerene derivative at the cathode surface in contact with active layer and rich in In at the cathode surface in contact with the ITO surface. Such doping in ZnO not only gives improved surface conductivity by a factor of 270 (from 0.015 to 4.06 S cm−1) but also provides enhanced electron mobility by a factor of 132 (from 8.25*10−5 to 1.09*10−2 cm2 V−1 s−1). The resulting i-PSC exhibits the improved PCE 10.31% relative to that with ZnO without doping 8.25%. This PCE 10.31% is the best result among the reported values so far for single junction PSC. PMID:25351472

  14. Efficiency consideration of DC link soft-switching inverters for motor drive applications

    SciTech Connect

    Lai, J.S.; Young, R.W.; McKeever, J.W.

    1994-12-31

    This paper critically evaluates efficiency of soft switching inverters including an actively clamped resonant dc link inverter and a clamped-mode resonant pole inverter. An analytical approach to evaluating efficiency of the clamped-mode soft switching inverter has been developed. The evaluation results are compared with that of the standard pulse-width-modulation (PWM) inverter. A 50-kW induction motor is used as the variable load, and the inverter efficiency is evaluated under different speed and torque conditions. The clamped-mode soft-switching inverter, although eliminating the switching loss, shows poor efficiency over the entire load range. Under low load conditions, the efficiency profile is even worse. The actively clamped resonant dc link inverter shows highest efficiency over the entire speed and torque range. However, its energy saving over the standard PWM inverter is marginal under full load or high speed conditions.

  15. The pathology of urinary bladder lesions with an inverted growth pattern.

    PubMed

    Guo, Aitao; Liu, Aijun; Teng, Xiaodong

    2016-02-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn's nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade. PMID:27041933

  16. The pathology of urinary bladder lesions with an inverted growth pattern

    PubMed Central

    Liu, Aijun; Teng, Xiaodong

    2016-01-01

    Inverted lesions in the urinary bladder have been the source of some difficulty in urological pathology. The two common ones are von Brunn’s nests and cystitis cystic/cystitis glandularis, which are considered normal variants of urothelium. Apart from them, a number of other rare urothelial lesions with inverted growth pattern occur in the urinary bladder. Some of them are only reactive conditions, just as pseudocarcinomatous hyperplasia. Some are benign tumors, namely inverted papilloma. Whereas others are malignant neoplasms, including inverted papillary urothelial neoplasm of low malignant potential (PUNLMP), non-invasive inverted papillary urothelial carcinoma (low-grade and high-grade), and invasive urothelial carcinoma (inverted, nested and big nested variants). Because of the overlapping morphological features of all the inverted lesions mentioned above, even between high-grade invasive carcinoma and pseudocarcinomatous hyperplasia which are only a kind of reactive conditions, it is very important for the surgical pathologist to recognize and be familiar with these inverted lesions in urinary bladder. In this article, we review these spectrums of inverted lesions of the urinary bladder. Emphasis is placed on histogenesis, morphology, differential diagnosis of these lesions, and the pathologic grading of the non-invasive inverted neoplasms, such as inverted papilloma, inverted PUNLMP, non-invasive inverted papillary urothelial carcinoma with low-grade, and non-invasive inverted papillary urothelial carcinoma with high-grade. PMID:27041933

  17. Dynamics of liquid sloshing in upright and inverted bladdered tanks

    NASA Astrophysics Data System (ADS)

    Dodge, F. T.; Kana, D. D.

    A system identification methodology was used to examine the dynamics of liquid sloshing in the upright and inverted bladdered hydrazine tanks of the Tracking and Data Relay Satellite, (TDRS) and to evaluate the effects of bladder stiffness on the sloshing parameters. Mechanical models of the two systems were developed using the numerical values derived from static stability tests and from slosh frequency response tests of a full-size model tank fitted with a prototype bladder. For the upright tank (liquid below the bladder) a modified conventional pendulum was used. In the inverted tank (liquid above the bladder) where sloshing is unconventional due to the highly nonsymmetrical orientation of the liquid held by the bladder, a mechanical model using an inverted pendulum which is able to undergo small oscillations as well as large reorientations was necessary. Both thrusting and low-gravity conditions are considered.

  18. Dynamics of liquid sloshing in upright and inverted bladdered tanks

    NASA Technical Reports Server (NTRS)

    Dodge, F. T.; Kana, D. D.

    1985-01-01

    A system identification methodology was used to examine the dynamics of liquid sloshing in the upright and inverted bladdered hydrazine tanks of the Tracking and Data Relay Satellite, (TDRS) and to evaluate the effects of bladder stiffness on the sloshing parameters. Mechanical models of the two systems were developed using the numerical values derived from static stability tests and from slosh frequency response tests of a full-size model tank fitted with a prototype bladder. For the upright tank (liquid below the bladder) a modified conventional pendulum was used. In the inverted tank (liquid above the bladder) where sloshing is unconventional due to the highly nonsymmetrical orientation of the liquid held by the bladder, a mechanical model using an inverted pendulum which is able to undergo small oscillations as well as large reorientations was necessary. Both thrusting and low-gravity conditions are considered.

  19. Transparent film with inverted conical microholes array for reflection enhancement

    NASA Astrophysics Data System (ADS)

    Lei, Biao; Liu, Hongzhong; Jiang, Weitao; Chen, Bangdao; Shi, Yongsheng; Yin, Lei; Liu, Xiaokang

    2016-04-01

    PDMS has been widely utilized for microfluidic chips and microchannel detections, as its good optical properties are the prerequisite to achieve accurate and efficient detection. However, it is difficult to obtain effective information for opaque liquids. With the development of microchannel detection for wider fields, it is imperative to obtain more comprehensive information of the observed objects by integrating high transmission with enhanced reflection. This article investigates reflection enhancement by Polydimethylsiloxane (PDMS) film with inverted conical microholes array. PDMS film with inverted conical microholes array is fabricated by replication from the silicon mold with inverted microcones array which is prepared by Inductively Coupled Plasma (ICP) etch tool. The monolayer PDMS film with inverted conical microholes array shows a two-fold effectively increase in reflection, approximately up to 15%, at a broad wavelength range of 637-1131 nm and 1214-1350 nm, compared with bare PDMS film. In addition, the reflection can be further enhanced by multilayered lamination of PDMS film with inverted conical microholes array, and the enhancement is also dependent on the lamination way, i.e., for bilayer laminations, the maximum reflection enhancement occurs when with face-to-back lamination, and 32.79% larger than that with back-to-face lamination. From the experiments, the maximum reflectivity of 8-layered PDMS films can obtain 64.4% while the maximum reflectivity of monolayer PDMS film barely has 17.5%. The transparent film with inverted conical microholes array for reflection enhancement may find a variety of applications in optical devices, microchips, and energy conservation technologies etc.

  20. Inverted organic photovoltaic device with a new electron transport layer

    PubMed Central

    2014-01-01

    We demonstrate that there is a new solution-processed electron transport layer, lithium-doped zinc oxide (LZO), with high-performance inverted organic photovoltaic device. The device exhibits a fill factor of 68.58%, an open circuit voltage of 0.86 V, a short-circuit current density of −9.35 cm/mA2 along with 5.49% power conversion efficiency. In addition, we studied the performance of blend ratio dependence on inverted organic photovoltaics. Our device also demonstrates a long stability shelf life over 4 weeks in air. PMID:24674457

  1. Toroidal transformer design program with application to inverter circuitry

    NASA Technical Reports Server (NTRS)

    Dayton, J. A., Jr.

    1972-01-01

    Estimates of temperature, weight, efficiency, regulation, and final dimensions are included in the output of the computer program for the design of transformers for use in the basic parallel inverter. The program, written in FORTRAN 4, selects a tape wound toroidal magnetic core and, taking temperature, materials, core geometry, skin depth, and ohmic losses into account, chooses the appropriate wire sizes and number of turns for the center tapped primary and single secondary coils. Using the program, 2- and 4-kilovolt-ampere transformers are designed for frequencies from 200 to 3200 Hz and the efficiency of a basic transistor inverter is estimated.

  2. Design and field performance of the KENETECH photovoltaic inverter system

    SciTech Connect

    Behnke, M.R.

    1995-11-01

    KENETECH Windpower has recently adapted the power conversion technology developed for the company`s variable speed wind turbine to grid-connected photovoltaic applications. KENETECH PV inverter systems are now in successful operation at the Sacramento Municipal Utility District`s (SMUD) Hedge Substation and the PVUSA-Davis site, with additional systems scheduled to be placed into service by the end of 1995 at SMUD, the New York Power Authority, Xerox Corporation`s Clean Air Now project, and the Georgia Tech Aquatic Center. The features of the inverter are described.

  3. Interaction between two side-by-side inverted flags

    NASA Astrophysics Data System (ADS)

    Huertas-Cerdeira, Cecilia; Fan, Boyu; Barizien, Antoine; Gharib, Morteza

    2015-11-01

    The inverted flag instability occurs when an elastic plate that is free at its leading edge and clamped at its trailing edge is subjected to an axial wind. The oscillating motion that follows has received recent attention. However, previous studies have focused on the dynamics of a single flag even though these are rarely found isolated in natural phenomena, such as the fluttering of leaves in the wind. The interaction between two side-by-side inverted flags has been investigated, analyzing the effects of the distance between flags and the wind speed. Both in-phase and anti-phase coupling have been observed for different ranges of these parameters.

  4. Inverter power module with distributed support for direct substrate cooling

    DOEpatents

    Miller, David Harold; Korich, Mark D.; Ward, Terence G.; Mann, Brooks S.

    2012-08-21

    Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

  5. Addressable Inverter Matrix Tests Integrated-Circuit Wafer

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G.

    1988-01-01

    Addressing elements indirectly through shift register reduces number of test probes. With aid of new technique, complex test structure on silicon wafer tested with relatively small number of test probes. Conserves silicon area by reduction of area devoted to pads. Allows thorough evaluation of test structure characteristics and of manufacturing process parameters. Test structure consists of shift register and matrix of inverter/transmission-gate cells connected to two-by-ten array of probe pads. Entire pattern contained in square area having only 1.6-millimeter sides. Shift register is conventional static CMOS device using inverters and transmission gates in master/slave D flip-flop configuration.

  6. Inverting hydrolases and their use in enantioconvergent biotransformations

    PubMed Central

    Schober, Markus; Faber, Kurt

    2013-01-01

    Owing to the more abundant occurrence of racemic compounds compared to prochiral or meso forms, most enantiomerically pure products are obtained via racemate resolution. This review summarizes (chemo)enzymatic enantioconvergent processes based on the use of hydrolytic enzymes, which are able to invert a stereocenter during catalysis that can overcome the 50%-yield limitation of kinetic resolution. Recent developments are presented in the fields of inverting or retaining sulfatases, epoxide hydrolases and dehalogenases, which allow the production of secondary alcohols or vicinal diols at a 100% theoretical yield from a racemate via enantioconvergent processes. PMID:23809848

  7. Geospeedometry in the inverted metamorphic gradient of the Nestos Thrust Zone in central Rhodope (Northern Greece)

    NASA Astrophysics Data System (ADS)

    Cioldi, Stefania; Moulas, Evangelos; Burg, Jean-Pierre

    2015-04-01

    Thrust tectonics and inverted metamorphic gradients are major consequences of large and likely fast movements of crustal segments in compressional environments. The purpose of this study is to investigate the tectonic setting and the timescale of inverted metamorphic zonations related to crustal-scale thrusting. The aim is to contribute understanding the link between mechanical and thermal evolution of major thrust zones and to clarify the nature and the origin of orogenic heat. The Rhodope metamorphic complex (Northern Greece) is interpreted as a part of the Alpine-Himalaya orogenic belt and represents a collisional system with an association of both large-scale thrusting and pervasive exhumation tectonics. The Nestos Shear Zone overprints the suture boundary with a NNE-dipping pile of schists displaying inverted isograds. The inverted metamorphic zones start from chlorite-muscovite grade at the bottom and reach kyanite-sillimanite grades with migmatites in the upper structural levels. In order to reconstruct the thermo-tectonic evolution of inverted metamorphic zonation, reliable geochronological data are essential. 40Ar/39Ar geochronology with step-heating technique on white mica from micaschists provided a temporal resolution with the potential to characterize shearing. 40Ar/39Ar dating across the Nestos Shear Zone yields Late Eocene-Early Oligocene (40-30 Ma) cooling (~400-350° C) ages, which correspond to local thermo-deformation episodes linked to late and post-orogenic intrusions. U-Pb Sensitive High Resolution Ion Microprobe (SHRIMP) zircon geochronology on leucosomes from migmatitic orthogneisses were considered to estimate the age of peak metamorphic conditions, contemporaneous with anatexis. U-Pb ages of zircon rims specify regional partial melting during the Early Cretaceous (160-120 Ma). This is in disagreement with previous assertions, which argued that the formation of leucosomes in this region is Late Eocene (42-35 Ma) and implied multiple

  8. Static inverter with synchronous output waveform synthesized by time-optimal-response feedback

    NASA Technical Reports Server (NTRS)

    Kernick, A.; Stechschulte, D. L.; Shireman, D. W.

    1976-01-01

    Time-optimal-response 'bang-bang' or 'bang-hang' technique, using four feedback control loops, synthesizes static-inverter sinusoidal output waveform by self-oscillatory but yet synchronous pulse-frequency-modulation (SPFM). A single modular power stage per phase of ac output entails the minimum of circuit complexity while providing by feedback synthesis individual phase voltage regulation, phase position control and inherent compensation simultaneously for line and load disturbances. Clipped sinewave performance is described under off-limit load or input voltage conditions. Also, approaches to high power levels, 3-phase arraying and parallel modular connection are given.

  9. Effect of simulated forward speed on the jet noise of inverted velocity profile coannular nozzles

    NASA Technical Reports Server (NTRS)

    Packman, A. B.; Ng, K. W.; Chen, C. Y.

    1977-01-01

    Tests were conducted of inverted velocity profile coannular nozzles and a conical nozzle in an acoustic wind tunnel facility to simulate flight effects on jet noise generation. Coannular model nozzles were tested at fan to core nozzle exit area ratios of .75 and 1.2. Fan stream jet velocity ranged up to 2000 fps at a variety of fan exhaust pressure ratios and temperatures for a core stream of 1000 fps. The wind tunnel airflow was varied from static to 425 fps. The acoustic results indicated that the noise level differences seen previously under static conditions are retained in the flight environment.

  10. Transparency in a Pediatric Quality Improvement Collaborative: A Passionate Journey by NPC-QIC Clinicians and Parents.

    PubMed

    Lihn, Stacey L; Kugler, John D; Peterson, Laura E; Lannon, Carole M; Pickles, Diane; Beekman, Robert H

    2015-01-01

    Transparency-sharing data or information about outcomes, processes, protocols, and practices-may be the most powerful driver of health care improvement. In this special article, the development and growth of transparency within the National Pediatric Cardiology Quality Improvement Collaborative is described. The National Pediatric Cardiology Quality Improvement Collaborative transparency journey is guided by equal numbers of clinicians and parents of children with congenital heart disease working together in a Transparency Work Group. Activities are organized around four interrelated levels of transparency (individual, organizational, collaborative, and system), each with a specified purpose and aim. A number of Transparency Work Group recommendations have been operationalized. Aggregate collaborative performance is now reported on the public-facing web site. Specific information that the Transparency Work Group recommends centers provide to parents has been developed and published. Almost half of National Pediatric Cardiology Quality Improvement Collaborative centers participated in a pilot of transparently sharing their outcomes achieved with one another. Individual centers have also begun successfully implementing recommended transparency activities. Despite progress, barriers to full transparency persist, including health care organization concerns about potential negative effects of disclosure on reputation and finances, and lack of reliable definitions, data, and reporting standards for fair comparisons of centers. The National Pediatric Cardiology Quality Improvement Collaborative's transparency efforts have been a journey that continues, not a single goal or destination. Balanced participation of clinicians and parents has been a critical element of the collaborative's success on this issue. Plans are in place to guide implementation of additional transparency recommendations across all four levels, including extension of the activities beyond the

  11. 8. TEST STAND 15, INVERTED ENGINE FIRING TEST, CIRCA 1963. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. TEST STAND 1-5, INVERTED ENGINE FIRING TEST, CIRCA 1963. Original is a color print. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

  12. Controlling An Inverter-Driven Three-Phase Motor

    NASA Technical Reports Server (NTRS)

    Dolland, C.

    1984-01-01

    Control system for three-phase permanent-magnet motor driven by linecommutated inverter uses signals generated by integrating back emf of each phase of motor. High-pass filter network eliminates low-frequency components from control loop while maintaining desired power factor.

  13. Learning Under Stress: The Inverted-U-Shape Function Revisited

    ERIC Educational Resources Information Center

    Salehi, Basira; Cordero, M. Isabel; Sandi, Carmen

    2010-01-01

    Although the relationship between stress intensity and memory function is generally believed to follow an inverted-U-shaped curve, strikingly this phenomenon has not been demonstrated under the same experimental conditions. We investigated this phenomenon for rats' performance in a hippocampus-dependent learning task, the radial arm water maze…

  14. Design and material selection for inverter transformer cores

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    Report is announced which studied magnetic properties of candidate materials for use in spacecraft transformers, static inverters, converters, and transformer-rectifier power supplies. Included are material characteristics for available alloy compositions in tabular form, including: trade names, saturated flux density, dc coercive force, loop squareness, material density, and watts per pound at 3 KHz.

  15. Processing of Inverted Files in Magnetic Bubble Memories.

    ERIC Educational Resources Information Center

    Zaki, M.; Elboraey, F.

    1985-01-01

    Investigates applicability of inverted file processing in magnetic bubble memories by presenting four magnetic bubble memory models as storage mediums: one based on a major-minor loop configuration; one utilizing a decoder design on a magnetic bubble memory chip; and two based on different structural configurations of the first two. (MBR)

  16. Can Holistic Processing Be Learned for Inverted Faces?

    ERIC Educational Resources Information Center

    Robbins, Rachel; McKone, Elinor

    2003-01-01

    The origin of "special" processing for upright faces has been a matter of ongoing debate. If it is due to generic expertise, as opposed to having some innate component, holistic processing should be learnable for stimuli other than upright faces. Here we assess inverted faces. We trained subjects to discriminate identical twins using up to 1100…

  17. Treatment of inverted nipples using a disposable syringe.

    PubMed

    Kesaree, N; Banapurmath, C R; Banapurmath, S; Shamanur, K

    1993-03-01

    Seven mothers who had inverted nipples were helped to breastfeed their infants with the assistance of a simple device made from a 10 ml disposable syringe. These women were able to successfully breastfeed within one week. On follow-up, these mothers were able to sustain adequate breastfeeding. PMID:8489719

  18. Inverted Meckel's diverticulum preoperatively diagnosed using double-balloon enteroscopy.

    PubMed

    Takagaki, Kosuke; Osawa, Satoshi; Ito, Tatsuhiro; Iwaizumi, Moriya; Hamaya, Yasushi; Tsukui, Hiroe; Furuta, Takahisa; Wada, Hidetoshi; Baba, Satoshi; Sugimoto, Ken

    2016-05-01

    An inverted Meckel's diverticulum is a rare gastrointestinal congenital anomaly that is difficult to diagnose prior to surgery and presents with anemia, abdominal pain, or intussusception. Here, we report the case of 57-year-old men with an inverted Meckel's diverticulum, who was preoperatively diagnosed using double-balloon enteroscopy. He had repeatedly experienced epigastric pain for 2 mo. Ultrasonography and computed tomography showed intestinal wall thickening in the pelvis. Double-balloon enteroscopy via the anal route was performed for further examination, which demonstrated an approximately 8-cm, sausage-shaped, submucosal tumor located approximately 80 cm proximal to the ileocecal valve. A small depressed erosion was observed at the tip of this lesion. Forceps biopsy revealed heterotopic gastric mucosa. Thus, the patient was diagnosed with an inverted Meckel's diverticulum, and single-incision laparoscopic surgery was performed. This case suggests that an inverted Meckel's diverticulum should be considered as a differential diagnosis for a submucosal tumor in the ileum. Balloon-assisted enteroscopy with forceps biopsy facilitate a precise diagnosis of this condition. PMID:27158212

  19. Regenerative Snubber For GTO-Commutated SCR Inverter

    NASA Technical Reports Server (NTRS)

    Rippel, Wally E.; Edwards, Dean B.

    1992-01-01

    Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.

  20. High voltage power supply with modular series resonant inverters

    DOEpatents

    Dreifuerst, Gary R.; Merritt, Bernard T.

    1995-01-01

    A relatively small and compact high voltage, high current power supply for a laser utilizes a plurality of modules containing series resonant half bridge inverters. A pair of reverse conducting thyristors are incorporated in each series resonant inverter module such that the series resonant inverter modules are sequentially activated in phases 360.degree./n apart, where n=number of modules for n>2. Selective activation of the modules allows precise output control reducing ripple and improving efficiency. Each series resonant half bridge inverter module includes a transformer which has a cooling manifold for actively circulating a coolant such as water, to cool the transformer core as well as selected circuit elements. Conductors connecting and forming various circuit components comprise hollow, electrically conductive tubes such as copper. Coolant circulates through the tubes to remove heat. The conductive tubes act as electrically conductive lines for connecting various components of the power supply. Where it is desired to make electrical isolation breaks, tubes comprised of insulating material such as nylon are used to provide insulation and continue the fluid circuit.

  1. High voltage power supply with modular series resonant inverters

    DOEpatents

    Dreifuerst, G.R.; Merritt, B.T.

    1995-07-18

    A relatively small and compact high voltage, high current power supply for a laser utilizes a plurality of modules containing series resonant half bridge inverters. A pair of reverse conducting thyristors are incorporated in each series resonant inverter module such that the series resonant inverter modules are sequentially activated in phases 360{degree}/n apart, where n=number of modules for n>2. Selective activation of the modules allows precise output control reducing ripple and improving efficiency. Each series resonant half bridge inverter module includes a transformer which has a cooling manifold for actively circulating a coolant such as water, to cool the transformer core as well as selected circuit elements. Conductors connecting and forming various circuit components comprise hollow, electrically conductive tubes such as copper. Coolant circulates through the tubes to remove heat. The conductive tubes act as electrically conductive lines for connecting various components of the power supply. Where it is desired to make electrical isolation breaks, tubes comprised of insulating material such as nylon are used to provide insulation and continue the fluid circuit. 11 figs.

  2. Invertible apparatus for the reflection of solar radiation

    SciTech Connect

    Urruela, J.R.

    1981-04-28

    Apparatus for reflecting light including a head carrying a reflecting panel and mounted for rotation on a column, said head including a mechanism for rotating said panel about a horizontal axis between a first range of positions for following the sun and an inverted position, said mechanism including an articulated quadrilateral controlled by a linear actuator.

  3. Malicious attacks on media authentication schemes based on invertible watermarks

    NASA Astrophysics Data System (ADS)

    Katzenbeisser, Stefan; Dittmann, Jana

    2004-06-01

    The increasing availability and distribution of multimedia technology has made the manipulation of digital images, videos or audio files easy. While this enables numerous new applications, a certain loss of trust in digital media can be observed. In general, there is no guarantee that a digital image "does not lie", i.e., that the image content was not altered. To counteract this risk, fragile watermarks were proposed to protect the integrity of digital multimedia objects. In high security applications, it is necessary to be able to reconstruct the original object out of the watermarked version. This can be achieved by the use of invertible watermarks. While traditional watermarking schemes introduce some small non-invertible distortion in the digital content, invertible watermarks can be completely removed from a watermarked work. In the past, the security of proposed image authentication schemes based on invertible watermarks was only analyzed using ad-hoc methods and neglected the possibility of malicious attacks, which aim at engineering a fake mark so that the attacked object appears to be genuine. In this paper, we characterize and analyze possible malicious attacks against watermark-based image authentication systems and explore the theoretical limits of previous constructions with respect to their security.

  4. Effects of morphology on the flapping dynamics of inverted flags

    NASA Astrophysics Data System (ADS)

    Fan, Boyu; Cosse, Julia; Sader, John; Gharib, Morteza

    2014-11-01

    The behavior of inverted flags has received recent attention in the study of the interaction of flexible bodies with fluid flows. It has implications in a variety of natural phenomena, such as the fluttering of leaves in the wind. As opposed to a conventional flag, defined by a fixed leading edge and a free trailing edge, an inverted flag has a free leading edge and a fixed trailing edge. The reversed flow orientation of inverted flags has led to a surprising observation. Over a narrow range of wind speeds, they exhibit a large-amplitude flapping motion that is not present in their conventional counterparts. Our study experimentally investigates the effects of flag morphology on the flapping behavior of inverted flags. Different flags ranging from rectangles to triangles are studied in a wind tunnel to assess the underlying parameters that govern their dynamics. We observe a significant shift in the limit-cycle flapping mode that is a function of flag shape parameters. This research is supported by the Lester Lees Aeronautics Summer Undergraduate Research Fellowship and the Gordon and Betty Moore Foundation.

  5. 3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR SURFACE HAULAGE OF MINE CARS, LOOKING SOUTHWEST; NOTE GEARING - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  6. A modified split-supply switched-reluctance drive inverter

    SciTech Connect

    Chan, S.; Omar, A.M.

    1995-12-31

    This paper describes the application of a new simple voltage-boosting feature to split-supply SR (switched-reluctance) inverter. As its name implies, the SR motor always operates in switching mode and has distinct motoring and generating rotor angular regions. The effectiveness of the energy conversion process of SR motor depends basically on the ability of its inverter to inject adequate current during the positive-torque angular region and to reduce the current to negligible value during negative-torque angular region. The modified inverter effectively generates boost voltages for accelerating current build-up and decay and hence enhances the performance of SR drives. Benefits of the added boosting include: higher average current, better energy recovery during commutation and a wider feasible speed range. This paper will assess the implications of the boost feature on inverter cost and performance. A time-stepping simulation procedure which includes the modelling of current overlapping between phases will be presented together with simulation results.

  7. Quenching mechanism of exciplex fluorescence by inverted micelles

    SciTech Connect

    Sato, Chika; Kikuchi, Koichi

    1992-06-25

    Using an emission-absorption laser photolysis method, the quenching mechanism of the pyrene-N,N-dimethylaniline exciplex fluorscence by inverted micelles is studied. The rate of enhanced intersystem crossing depends upon water pool size and is reduced by external magnetic fields. 15 refs., 3 figs., 2 tabs.

  8. Efficiency modeling and evaluation of a resonant snubber based soft- switching inverter for motor drive applications

    SciTech Connect

    Lai, J.S.; Young, R.W.; Ott, G.W.

    1995-12-31

    This paper establishes an analytical model for a resonant snubber based soft-switching inverter. The model adopts loss separation method to evaluate losses in individual components. Because of symmetry of the inverter circuit, the developed model is suitable for both single-phase and three-phase inverters. A single-phase inverter was built and tested with a single-phase induction motor driving a fan load to verify the developed model. The equivalent single-phase induction motor model was curve-fitted from experiment. Analytical results showed reasonable agreement with experiment. The same efficiency evaluation method was then applied to the conventional hard-switching inverter, and the results were compared with that of the soft-switching inverter. The resonant snubber base soft-switching inverter shows substantial efficiency improvement over the hard switching PWM (pulse-width-modulation) inverter, especially in low speed operation.

  9. Dosimetric difference amongst 3 techniques: TomoTherapy, sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC)

    SciTech Connect

    Lee, Francis Kar-ho Yip, Celia Wai-yi; Cheung, Frankie Chun-hung; Leung, Alex Kwok-cheung; Chau, Ricky Ming-chun; Ngan, Roger Kai-cheong

    2014-04-01

    To investigate the dosimetric difference amongst TomoTherapy, sliding-window intensity-modulated radiotherapy (IMRT), and RapidArc radiotherapy in the treatment of late-stage nasopharyngeal carcinoma (NPC). Ten patients with late-stage (Stage III or IV) NPC treated with TomoTherapy or IMRT were selected for the study. Treatment plans with these 3 techniques were devised according to departmental protocol. Dosimetric parameters for organ at risk and treatment targets were compared between TomoTherapy and IMRT, TomoTherapy and RapidArc, and IMRT and RapidArc. Comparison amongst the techniques was done by statistical tests on the dosimetric parameters, total monitor unit (MU), and expected delivery time. All 3 techniques achieved similar target dose coverage. TomoTherapy achieved significantly lower doses in lens and mandible amongst the techniques. It also achieved significantly better dose conformity to the treatment targets. RapidArc achieved significantly lower dose to the eye and normal tissue, lower total MU, and less delivery time. The dosimetric advantages of the 3 techniques were identified in the treatment of late-stage NPC. This may serve as a guideline for selection of the proper technique for different clinical cases.

  10. Bypass ZVS-PWM High-Frequency Inverter for Induction Heating

    NASA Astrophysics Data System (ADS)

    Shoji, Hiroyuki; Uruno, Junpei; Isogai, Masayuki

    In this paper, we present a novel circuit topology for achieving thezero-voltage switching (ZVS) operation in a high-frequency inverter. The output power of the inverter is regulated over a wide range using a pulse widthmodulation (PWM) technique and by connecting a bypass circuit to a conventional single-ended push-pull (SEPP) high-frequency inverter for induction heating. All the switching devices of the proposed inverter are operated in the ZVS mode.

  11. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, I.J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

  12. Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module

    DOEpatents

    Pitel, Ira J.

    1987-02-03

    The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

  13. The appearance of Ti3+ states in solution-processed TiOx buffer layers in inverted organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Zhidkov, Ivan S.; McLeod, John A.; Kurmaev, Ernst Z.; Korotin, Michael A.; Kukharenko, Andrey I.; Savva, Achilleas; Choulis, Stelios A.; Korotin, Danila M.; Cholakh, Seif O.

    2016-07-01

    We study the low-temperature solution processed TiOx films and device structures using core level and valence X-ray photoelectron spectroscopy (XPS) and electronic structure calculations. We are able to correlate the fraction of Ti3+ present as obtained from Ti 2p core level XPS with the intensity of the defect states that appear within the band gap as observed with our valence XPS. Constructing an operating inverted organic photovoltaic (OPV) using the TiOx film as an electron selective contact may increase the fraction of Ti3+ present. We provide evidence that the number of charge carriers in TiOx can be significantly varied and this might influence the performance of inverted OPVs.

  14. Variable-frequency inverter controls torque, speed, and braking in ac induction motors

    NASA Technical Reports Server (NTRS)

    Nola, F. J.

    1974-01-01

    Dc to ac inverter provides optimum frequency and voltage to ac induction motor, in response to different motor-load and speed requirements. Inverter varies slip frequency of motor in proportion to required torque. Inverter protects motor from high current surges, controls negative slip to apply braking, and returns energy stored in momentum of load to dc power source.

  15. The research of multilevel transistor inverter for converting energy of solar panels

    NASA Astrophysics Data System (ADS)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  16. Preliminary results of a randomized study (NPC-9902 Trial) on therapeutic gain by concurrent chemotherapy and/or accelerated fractionation for locally advanced nasopharyngeal carcinoma

    SciTech Connect

    Lee, Anne W.M. . E-mail: awmlee@ha.org.hk; Tung, Stewart Y.; Chan, Anthony T.C.; Chappell, Rick; Fu, Y.-T.; Lu, Tai-Xiang; Tan, Terence; Chua, Daniel T.T.; O'Sullivan, Brian; Xu, Shirley L.; Pang, Ellie S.Y.; Sze, W.-M.; Leung, T.-W.; Kwan, W.-H.; Chan, Paddy; Liu, X.-F.; Tan, E.-H.; Sham, Jonathan; Siu, Lillian; Lau, W.-H.

    2006-09-01

    Purpose: To compare the benefit achieved by concurrent chemoradiotherapy (CRT) and/or accelerated fractionation (AF) vs. radiotherapy (RT) alone with conventional fractionation (CF) for patients with T3-4N0-1M0 nasopharyngeal carcinoma (NPC). Methods and Materials: All patients were irradiated with the same RT technique to {>=}66 Gy at 2 Gy per fraction, conventional five fractions/week in the CF and CF+C (chemotherapy) arms, and accelerated six fractions/week in the AF and AF+C arms. The CF+C and AF+C patients were given the Intergroup 0099 regimen (concurrent cisplatin plus adjuvant cisplatin and 5-fluorouracil). Results: Between 1999 and April 2004, 189 patients were randomly assigned; the trial was terminated early because of slow accrual. The median follow-up was 2.9 years. When compared with the CF arm, significant improvement in failure-free survival (FFS) was achieved by the AF+C arm (94% vs. 70% at 3 years, p = 0.008), but both the AF arm and the CF+C arm were insignificant (p {>=} 0.38). Multivariate analyses showed that CRT was a significant factor: hazard ratio (HR) = 0.52 (0.28-0.97), AF per se was insignificant: HR = 0.68 (0.37-1.25); the interaction of CRT by AF was strongly significant (p = 0.006). Both CRT arms had significant increase in acute toxicities (p < 0.005), and the AF+C arm also incurred borderline increase in late toxicities (34% vs. 14% at 3 years, p = 0.05). Conclusions: Preliminary results suggest that concurrent chemoradiotherapy with accelerated fractionation could significantly improve tumor control when compared with conventional RT alone; further confirmation of therapeutic ratio is warranted.

  17. Geosat observations of sea level response to barometric pressure forcing

    NASA Technical Reports Server (NTRS)

    Hoar, Timothy J.; Wilson, Clark R.

    1994-01-01

    Altimeter and sea level pressure data from the Geosat mission are analyzed for evidence of inverted barometer responses of sea level to atmospheric pressure forcing. Estimates of the inverted barometer coefficient are given for a variety of geographic regions and time scales using various orbit error removal strategies. There is some sensitivity to the orbit error removal method, but the estimated coefficients show a clear latitudinal dependence and are generally between -0.5 cm/mbar and -0.9 cm/mbar. The southern oceans respond slightly more like an inverted barometer than the northern oceans for similar latitudes. The regression exhibits significant geographic variability, particularly near major circulation features and in the northern hemisphere. The results suggest that the inverted barometer approximation is resonable over much of the oceans, but that some sea level variability may be correlated with barometric pressure by means other than the inverted barometer effect.

  18. Solvent-responsive self-assembly of amphiphilic invertible polymers determined with SANS.

    PubMed

    Kudina, Olena; Kohut, Ananiy; Tarnavchyk, Ihor; Hevus, Ivan; Voronov, Andriy

    2014-04-01

    Amphiphilic invertible polymers (AIPs) are a new class of macromolecules that self-assemble into micellar structures and rapidly change structure in response to changes in solvent polarity. Using small-angle neutron scattering (SANS) data, we obtained a quantitative description of the invertible micellar assemblies (IMAs). The detailed composition and size of the assemblies (including the effect of temperature) were measured in aqueous and toluene polymer solutions. The results show that the invertible macromolecules self-assemble into cylindrical core-shell micellar structures. The composition of the IMAs in aqueous and toluene solutions was used to reveal the inversion mechanism by changing the polarity of the medium. Our experiments demonstrate that AIP unimers self-assemble into IMAs in aqueous solution, predominantly through interactions between the hydrophobic moieties of macromolecules. The hydrophobic effect (or solvophobic interaction) is the major driving force for self-assembly. When the polarity of the environment is changed from polar to nonpolar, poly(ethylene glycol) (PEG) and aliphatic dicarboxylic acid fragments of AIP macromolecules tend to replace each other in the core and the shell of the IMAs. However, neither the interior nor the exterior of the IMAs consists of fragments of a single component of the macromolecule. In aqueous solution, with the temperature increasing from 15 to 35 °C, the IMAs' mixed core from aliphatic dicarboxylic acid and PEG moieties and PEG-based shell change the structure. As a result of the progressive dehydration of the macromolecules, the hydration level (water content) in the micellar core decreases at 25 °C, followed by dehydrated PEG fragments entering the interior of the IMAs when the temperature increases to 35 °C. PMID:24606021

  19. Treatment of the benign inverted nipple: A systematic review and recommendations for future therapy.

    PubMed

    Hernandez Yenty, Q M; Jurgens, W J F M; van Zuijlen, P P M; de Vet, H C W; Verhaegen, P D H M

    2016-10-01

    The inverted nipple is a frequently encountered problem which can cause difficulties with breastfeeding, sexuality, and aesthetic dissatisfaction. Up to now, no consensus exists on a preferred treatment method. We performed a systematic review to identify the best treatment method for correction of benign inverted nipples. Treatment techniques were subdivided in the categories lactiferous duct preserving and lactiferous duct damaging. A systematic review was performed using the PRISMA statement. Inclusion criteria were: female patients with congenital or acquired inverted nipples, a minimum sample size of 10 nipples, and studies reporting recurrence of inversion with a minimum follow-up of six months. Exclusion criteria were nipple inversion caused by malignancy. Thirteen studies met the inclusion criteria which all had a level of evidence IV. No non-invasive treatment techniques were identified. In the duct preserving category eight studies were included with a recurrence rate of 0.6% (2/350) versus 9.9% (16/161) in the duct damaging category (n = 5). Other outcome parameters were not systematically reported in all studies. Because of a small number of low quality studies with heterogeneous interventions and outcomes a meta-analysis could not be performed and no preferred treatment method was identified. Based on the available data there is no statistical evidence that duct damaging treatment is superior to duct preserving treatment. We recommend that the first method of choice should be a duct preserving treatment method. In the future, more studies of better methodological quality are required and recommendations were made on how these could be conducted. PMID:27476082

  20. Epigenetics of eu- and heterochromatin in inverted and conventional nuclei from mouse retina.

    PubMed

    Eberhart, Anja; Feodorova, Yana; Song, Congdi; Wanner, Gerhard; Kiseleva, Elena; Furukawa, Takahisa; Kimura, Hiroshi; Schotta, Gunnar; Leonhardt, Heinrich; Joffe, Boris; Solovei, Irina

    2013-08-01

    To improve light propagation through the retina, the rod nuclei of nocturnal mammals are uniquely changed compared to the nuclei of other cells. In particular, the main classes of chromatin are segregated in them and form regular concentric shells in order; inverted in comparison to conventional nuclei. A broad study of the epigenetic landscape of the inverted and conventional mouse retinal nuclei indicated several differences between them and several features of general interest for the organization of the mammalian nuclei. In difference to nuclei with conventional architecture, the packing density of pericentromeric satellites and LINE-rich chromatin is similar in inverted rod nuclei; euchromatin has a lower packing density in both cases. A high global chromatin condensation in rod nuclei minimizes the structural difference between active and inactive X chromosome homologues. DNA methylation is observed primarily in the chromocenter, Dnmt1 is primarily associated with the euchromatic shell. Heterochromatin proteins HP1-alpha and HP1-beta localize in heterochromatic shells, whereas HP1-gamma is associated with euchromatin. For most of the 25 studied histone modifications, we observed predominant colocalization with a certain main chromatin class. Both inversions in rod nuclei and maintenance of peripheral heterochromatin in conventional nuclei are not affected by a loss or depletion of the major silencing core histone modifications in respective knock-out mice, but for different reasons. Maintenance of peripheral heterochromatin appears to be ensured by redundancy both at the level of enzymes setting the epigenetic code (writers) and the code itself, whereas inversion in rods rely on the absence of the peripheral heterochromatin tethers (absence of code readers). PMID:23996328

  1. Statistics of a noise-driven elastic inverted pendulum

    NASA Astrophysics Data System (ADS)

    Halvorsen, Einar; Litak, Grzegorz

    2015-04-01

    Recently an elastic inverted pendulum structure was proposed as a means to make nonlinear energy harvesters. An effective dynamical model of this bi-stable system has an effective lumped mass that is dependent on the displacement, hence preventing direct application of previous analyses for nonlinear harvesters driven by random vibrations. We have set up a stationary Fokker-Planck equation for the inverted pendulum and solved it to obtain explicit expressions for the stationary probability densities of the system. We found that the marginal distribution of velocity is non-Gaussian, but numerically it differs little from a Gaussian when parameters for a recently published device are used. The conditional probability of position given velocity, has two peaks for low velocities. These merge into one upon increase of velocity.

  2. Adaptive control system for line-commutated inverters

    NASA Technical Reports Server (NTRS)

    Dolland, C. R.; Bailey, D. A. (Inventor)

    1983-01-01

    A control system for a permanent magnet motor driven by a multiphase line commutated inverter is provided with integration for integrating the back EMF of each phase of the motor. This is used in generating system control signals for an inverter gate logic using a sync and firing angle (alpha) control generator connected to the outputs of the integrators. A precision full wave rectifier provides a speed control feedback signal to a phase delay rectifier via a gain and loop compensation circuit and to the integrators for adaptive control of the attenuation of low frequencies by the integrators as a function of motor speed. As the motor speed increases, the attenuation of low frequency components by the integrators is increased to offset the gain of the integrators to spurious low frequencies.

  3. Amphoteric water-in-oil self-inverting polymer emulsion

    SciTech Connect

    Lipowski, S. A.

    1985-11-12

    An amphoteric water-in-oil self-inverting polymer emulsion is prepared which contains a copolymer of a nonionic vinyl monomer and an amphoteric vinyl monomer or a terpolymer of a nonionic vinyl monomer, an anionic vinyl monomer and a cationic vinyl monomer in the aqueous phase, a hydrocarbon oil for the oil phase, a water-in-oil emulsifying agent and an inverting surfactant. An example of a copolymer is a copolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide and an amphoteric vinyl monomer such as a reaction product of dimethylaminoethyl methacrylate and monochloracetic acid. An example of a terpolymer is a terpolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide, an anionic vinyl monomer such as sodium acrylate and a cationic vinyl monomer such as triethyl ammonium ethyl methacrylate methosulfate salt. The emulsion is useful in papermaking, treatment of sewage and industrial wastes, drilling muds and secondary and tertiary recovery of petroleum by water flooding.

  4. Tripless control method for general-purpose inverters

    SciTech Connect

    Mutoh, N.; Ueda, A. . Hitachi Research Lab.); Nandoh, K.; Ibori, S. )

    1992-09-01

    In this paper a new control method is described. This method prevents general-purpose inverters without current regulators from tripping easily, i.e., to be tripless no matter how their load is varied, and enables motors to rotate stably at high frequencies. This control is performed using only current sensors and is a combination of PWM control and torque control. This approach for PWM control changes an asynchronized mode to a synchronized mode when the modulation ratio becomes more than one. This enables the carrier wave frequency to be continuously varied with the inverter frequency. As a result, motors can rotate stably over a wide frequency range. The torque control uses a real and reactive component detector, magnetic flux compensator, slip compensator, and current limit controller.

  5. PWM Inverter control and the application thereof within electric vehicles

    DOEpatents

    Geppert, Steven

    1982-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

  6. Inverter-based GTA welding machines improve fabrication

    SciTech Connect

    Sammons, M.

    2000-05-01

    While known as precision process, many fabricators using the gas tungsten arc welding (GTAW) process fight several common problems that hinder quality, slow production, frustrate the operator and otherwise prevent the process from achieving its full potential. These include a limited ability to tailor the weld bead profile, poor control of the arc direction and arc wandering, poor arc starting, unstable or inconsistent arcs in the AC mode, high-frequency interference with electronics and tungsten contamination. Fortunately, new GTA welding technology--made possible by advances with inverter-based power sources and micro-processor controls--can eliminate common productivity gremlins. Further, new AC/DC inverter-based GTA power sources provide advanced arc shaping capabilities. As a result, many fabricators adopting this new technology have experienced phenomenal production increases, taken on new types of projects and reduced costs. Most importantly, the operators enjoy welding more.

  7. Modular synthetic inverters from zinc finger proteins and small RNAs

    DOE PAGESBeta

    Hsia, Justin; Holtz, William J.; Maharbiz, Michel M.; Arcak, Murat; Keasling, Jay D.; Rao, Christopher V.

    2016-02-17

    Synthetic zinc finger proteins (ZFPs) can be created to target promoter DNA sequences, repressing transcription. The binding of small RNA (sRNA) to ZFP mRNA creates an ultrasensitive response to generate higher effective Hill coefficients. Here we combined three “off the shelf” ZFPs and three sRNAs to create new modular inverters in E. coli and quantify their behavior using induction fold. We found a general ordering of the effects of the ZFPs and sRNAs on induction fold that mostly held true when combining these parts. We then attempted to construct a ring oscillator using our new inverters. In conclusion, our chosenmore » parts performed insufficiently to create oscillations, but we include future directions for improvement upon our work presented here.« less

  8. Nonlinear analysis of a family of LC tuned inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1975-01-01

    Four widely used self-oscillating dc-to-square-wave parallel inverters which employ an inductor-capacitor tuned network to determine the oscillation frequency are reduced to a common equivalent RLC network, The techniques of singular-point analysis and state-plane interpretations are employed to describe the steady-state and transient behavior of these circuits and to elucidate the three possible modes of operation: quasi-harmonic, relaxation, and discontinuous. Design guidelines are provided through a study of the influence of circuit parameter variations on the characteristics of oscillation and on frequency stability. Several examples are provided to illustrate the usefulness of this analysis when studying such problems as transistor emitter-to-base junction breakdown during oscillations and the design of starting circuits to insure self-excited oscillations in these inverters.

  9. Completely inverted hysteresis loops: Inhomogeneity effects or experimental artifacts

    SciTech Connect

    Song, C. Cui, B.; Pan, F.; Yu, H. Y.

    2013-11-14

    Completely inverted hysteresis loops (IHL) are obtained by the superconducting quantum interference device with large cooling fields (>10 kOe) in (La,Sr)MnO{sub 3} films with self-assembled LaSrMnO{sub 4}, an antiferromagnetic interface. Although the behaviours of measured loops show many features characteristic to the IHL, its origin, however, is not due to the exchange coupling between (La,Sr)MnO{sub 3}/LaSrMnO{sub 4}, an often accepted view on IHL. Instead, we demonstrate that the negative remanence arises from the hysteresis of superconducting coils, which drops abruptly when lower cooling fields are utilized. Hence the completely inverted hysteresis loops are experimental artifacts rather than previously proposed inhomogeneity effects in complicated materials.

  10. Modular Synthetic Inverters from Zinc Finger Proteins and Small RNAs

    PubMed Central

    Hsia, Justin; Holtz, William J.; Maharbiz, Michel M.; Arcak, Murat; Keasling, Jay D.

    2016-01-01

    Synthetic zinc finger proteins (ZFPs) can be created to target promoter DNA sequences, repressing transcription. The binding of small RNA (sRNA) to ZFP mRNA creates an ultrasensitive response to generate higher effective Hill coefficients. Here we combined three “off the shelf” ZFPs and three sRNAs to create new modular inverters in E. coli and quantify their behavior using induction fold. We found a general ordering of the effects of the ZFPs and sRNAs on induction fold that mostly held true when combining these parts. We then attempted to construct a ring oscillator using our new inverters. Our chosen parts performed insufficiently to create oscillations, but we include future directions for improvement upon our work presented here. PMID:26886888

  11. Current control loop of 3-phase grid-connected inverter

    NASA Astrophysics Data System (ADS)

    Jabbar, A. F.; Mansor, M.

    2013-06-01

    This paper presents a comparative study of current control loop in 3-phase inverter which is used to control the active and reactive output power. Generally, current control loop, power control loop and phase lock-loop are the conventional parameters that can be found in an inverter system controlled by the conventional linear control type, for instance proportional (P), integral (I) and derivative (D). If the grid remains stable throughout the day, PID control can be use. However variation of magnitude, frequency, voltage dips, transient, and other related power quality issues occur in a 3-phase grid often affects the control loop. This paper aims to provide an overall review on the available current control techniques used in grid connected system.

  12. Equilibrium and Stability of the Brillouin Flow in Inverted Magnetron

    NASA Astrophysics Data System (ADS)

    Simon, David; Lau, Yue Ying; Franzi, Matt; Greening, Geoff; Gilgenbach, Ronald; Marhdahl, Peter; Hoff, Brad; Luginsland, John

    2012-10-01

    One embodiment of the novel recirculating planar magnetron, RPM [1] utilizes an inverted configuration for fast startup. While the negative mass behavior on the thin electron layer model [2] is well-known for the inverted magnetron, the corresponding behavior for the equilibrium Brillouin flow [3] is an open question. Simulations using the particle-in-cell codes ICEPIC and/or MAGIC will be performed and compared to the solution to the eigenvalue problem that governs the stability of Brillouin flow, leading to a fundamental study of the flow's negative, positive, and infinite mass properties. Research supported by AFOSR (grant#: FA9550-10-1-0104), AFRL, and L-3 Communications Electron Devices. [4pt] [1] R. M. Gilgenbach, et.al., IEEE Trans. Plasma Sci. 39, 980 (2011); Also patent pending.[0pt] [2] D. M. French, et al., Appl. Phys. Lett. 97, 111501 (2010).[0pt] [3] D. Simon, et al., Phys. Plasmas 19, 043103 (2012).

  13. A state observer for the Virgo inverted pendulum

    NASA Astrophysics Data System (ADS)

    Accadia, T.; Acernese, F.; Astone, P.; Ballardin, G.; Barone, F.; Barsuglia, M.; Basti, A.; Bauer, Th. S.; Bebronne, M.; Beker, M. G.; Belletoile, A.; Bitossi, M.; Bizouard, M. A.; Blom, M.; Bondu, F.; Bonelli, L.; Bonnand, R.; Boschi, V.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Branchesi, M.; Briant, T.; Brillet, A.; Brisson, V.; Bulik, T.; Bulten, H. J.; Buskulic, D.; Buy, C.; Cagnoli, G.; Calloni, E.; Canuel, B.; Carbognani, F.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cesarini, E.; Chaibi, O.; Chassande-Mottin, E.; Chincarini, A.; Chiummo, A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Corsi, A.; Coulon, J.-P.; Cuoco, E.; D'Antonio, S.; Dattilo, V.; Davier, M.; Day, R.; De Rosa, R.; Debreczeni, G.; Del Pozzo, W.; del Prete, M.; Di Fiore, L.; Di Lieto, A.; Emilio, M. Di Paolo; Virgilio, A. Di; Dietz, A.; Drago, M.; Endrőczi, G.; Fafone, V.; Ferrante, I.; Fidecaro, F.; Fiori, I.; Flaminio, R.; Forte, L. A.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Galimberti, M.; Gammaitoni, L.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Genin, E.; Gennai, A.; Giazotto, A.; Gouaty, R.; Granata, M.; Greverie, C.; Guidi, G. M.; Hayau, J.-F.; Heidmann, A.; Heitmann, H.; Hello, P.; Jaranowski, P.; Kowalska, I.; Królak, A.; Leroy, N.; Letendre, N.; Li, T. G. F.; Liguori, N.; Lorenzini, M.; Loriette, V.; Losurdo, G.; Majorana, E.; Maksimovic, I.; Man, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marque, J.; Martelli, F.; Masserot, A.; Michel, C.; Milano, L.; Minenkov, Y.; Mohan, M.; Morgado, N.; Morgia, A.; Mours, B.; Naticchioni, L.; Nocera, F.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Paoletti, F.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Persichetti, G.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Poggiani, R.; Prato, M.; Prodi, G. A.; Punturo, M.; Puppo, P.; Rabeling, D. S.; Rácz, I.; Rapagnani, P.; Re, V.; Regimbau, T.; Ricci, F.; Robinet, F.; Rocchi, A.; Rolland, L.; Romano, R.; Rosińska, D.; Ruggi, P.; Sassolas, B.; Sentenac, D.; Sperandio, L.; Sturani, R.; Swinkels, B.; Tacca, M.; Taffarello, L.; Toncelli, A.; Tonelli, M.; Torre, O.; Tournefier, E.; Travasso, F.; Vajente, G.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; Vasuth, M.; Vavoulidis, M.; Vedovato, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinet, J.-Y.; Vitale, S.; Vocca, H.; Ward, R. L.; Was, M.; Yvert, M.; Zadroźny, A.; Zendri, J.-P.

    2011-09-01

    We report an application of Kalman filtering to the inverted pendulum (IP) of the Virgo gravitational wave interferometer. Using subspace method system identification techniques, we calculated a linear mechanical model of Virgo IP from experimental transfer functions. We then developed a Kalman filter, based on the obtained state space representation, that estimates from open loop time domain data, the state variables of the system. This allows the observation (and eventually control) of every resonance mode of the IP mechanical structure independently.

  14. Optimization of Nanowire-Resistance Load Logic Inverter.

    PubMed

    Hashim, Yasir; Sidek, Othman

    2015-09-01

    This study is the first to demonstrate characteristics optimization of nanowire resistance load inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. Results indicate that optimization depends on resistance value. Increasing of load resistor tends to increasing in noise margins until saturation point, increasing load resistor after this point will not improve noise margins significantly. PMID:26716253

  15. Turning water into rock: The inverted waves effect.

    PubMed

    Häkkinen, Jukka; Gröhn, Lauri

    2016-01-01

    Humans perceive shape in two-dimensional shaded images, and turning such an image upside down can result in inversion of the relief of this image. Previous research indicates that this inversion is caused by assumptions related to overhead illumination, global convexity and viewpoint above the surface. In our article, we describe the inverted waves effect, in which turning an image of waves upside down changes its relief and also its perceived material properties. PMID:27482371

  16. Lyapunov optimal feedback control of a nonlinear inverted pendulum

    NASA Technical Reports Server (NTRS)

    Grantham, W. J.; Anderson, M. J.

    1989-01-01

    Liapunov optimal feedback control is applied to a nonlinear inverted pendulum in which the control torque was constrained to be less than the nonlinear gravity torque in the model. This necessitates a control algorithm which 'rocks' the pendulum out of its potential wells, in order to stabilize it at a unique vertical position. Simulation results indicate that a preliminary Liapunov feedback controller can successfully overcome the nonlinearity and bring almost all trajectories to the target.

  17. Control of the constrained planar simple inverted pendulum

    NASA Technical Reports Server (NTRS)

    Bavarian, B.; Wyman, B. F.; Hemami, H.

    1983-01-01

    Control of a constrained planar inverted pendulum by eigenstructure assignment is considered. Linear feedback is used to stabilize and decouple the system in such a way that specified subspaces of the state space are invariant for the closed-loop system. The effectiveness of the feedback law is tested by digital computer simulation. Pre-compensation by an inverse plant is used to improve performance.

  18. Turning water into rock: The inverted waves effect

    PubMed Central

    Gröhn, Lauri

    2016-01-01

    Humans perceive shape in two-dimensional shaded images, and turning such an image upside down can result in inversion of the relief of this image. Previous research indicates that this inversion is caused by assumptions related to overhead illumination, global convexity and viewpoint above the surface. In our article, we describe the inverted waves effect, in which turning an image of waves upside down changes its relief and also its perceived material properties. PMID:27482371

  19. High Peak Power Gyroklystron with an Inverted Magnetron Injection Gun

    NASA Astrophysics Data System (ADS)

    Read, Michael; Neilson, Jeff; Borchard, Philipp; Ives, Lawrence; Lawson, Wes

    2006-01-01

    This paper describes the design of a 25 MW, 30 GHz gyroklystron amplifier based on a coaxial RF structure. The design includes an inverted magnetron injection gun (MIG) for positioning and cooling the inner conductor. The gun produces a very low spread beam that contributes to a device efficiency of 54%. Details are given of the gun, RF structure, input and output couplers and collector.

  20. GAP analysis towards a design qualification standard development for grid-connected photovoltaic inverters.

    SciTech Connect

    Tamizhmani, Govindasamy; Granata, Jennifer E.; Maracas, George; Ayyanar, Raja; Marinella, Matthew; Venkataramanan, Sai Balasubramanian Alampoondi

    2011-06-01

    A dedicated design qualification standard for PV inverters does not exist. Development of a well-accepted design qualification standard, specifically for PV inverters will significantly improve the reliability and performance of inverters. The existing standards for PV inverters such as ANSI/UL 1741 and IEC 62109-1 primarily focus on safety of PV inverters. The IEC 62093 discusses inverter qualification but it includes all the BOS components. There are other general standards for distributed generators including the IEEE 1547 series of standards which cover major concerns like utility integration but they are not dedicated to PV inverters and are not written from a design qualification point of view. In this paper some of the potential requirements for a design qualification standard for PV inverters are addressed. The missing links in existing PV inverter related standards are identified and with the IEC 62093 as a guideline, the possible inclusions in the framework for a dedicated design qualification standard of PV inverter are discussed. Some of the key missing links are related to electric stress tests. Hence, a method to adapt the existing surge withstand test standards for use in design qualification standard of PV inverter is presented.

  1. An SCR inverter with an integral battery charger for electric vehicles

    NASA Technical Reports Server (NTRS)

    Thimmeach, D.

    1983-01-01

    The feasibility of incorporating an onboard battery charger into the inverter previously developed under a NASA contract is successfully demonstrated. The rated output power of the resulting isolated battery charger is 3.6 kW at 220 Vac with an 86 percent efficiency and a 95 percent power factor. Also achieved are improved inverter efficiency (from 90 to 93 percent at 15 kW motor shaft power), inverter peak power capability (from 26 to 34 kW), and reduced weight and volume of the combined inverter/charger package (47 kg, 49 x 44 x 24 cm). Some major conclusions are that using the inverter commutation circuitry to perform the battery charging function is advantageous, and that the input-commutated thyristor inverter has the potential to be an excellent inverter and battery charger for use in electric vehicle applications.

  2. Inverted channel deposits on the floor of Miyamoto crater, Mars

    USGS Publications Warehouse

    Newsom, Horton E.; Lanza, N.L.; Ollila, A.M.; Wiseman, S.M.; Roush, T.L.; Marzo, G.A.; Tornabene, L.L.; Okubo, C.H.; Osterloo, M.M.; Hamilton, V.E.; Crumpler, L.S.

    2010-01-01

    Morphological features on the western floor of Miyamoto crater in southwestern Meridiani Planum, Mars, are suggestive of past fluvial activity. Imagery from the High Resolution Imaging Science Experiment (HiRISE) gives a detailed view of raised curvilinear features that appear to represent inverted paleochannel deposits. The inverted terrain appears to be capped with a resistant, dark-toned deposit that is partially covered by unconsolidated surficial materials. Subsequent to deposition of the capping layer, erosion of the surrounding material has left the capping materials perched on pedestals of uneroded basal unit material. Neither the capping material nor the surrounding terrains show any unambiguous morphological evidence of volcanism or glaciation. The capping deposit may include unconsolidated or cemented stream deposits analogous to terrestrial inverted channels in the Cedar Mountain Formation near Green River, Utah. In addition to this morphological evidence for fluvial activity, phyllosilicates have been identified in the basal material on the floor of Miyamoto crater by orbital spectroscopy, providing mineralogical evidence of past aqueous activity. Based on both the morphological and mineralogical evidence, Miyamoto crater represents an excellent site for in situ examination and sampling of a potentially habitable environment. ?? 2009 Elsevier Inc.

  3. Orbifold E-functions of dual invertible polynomials

    NASA Astrophysics Data System (ADS)

    Ebeling, Wolfgang; Gusein-Zade, Sabir M.; Takahashi, Atsushi

    2016-08-01

    An invertible polynomial is a weighted homogeneous polynomial with the number of monomials coinciding with the number of variables and such that the weights of the variables and the quasi-degree are well defined. In the framework of the search for mirror symmetric orbifold Landau-Ginzburg models, P. Berglund and M. Henningson considered a pair (f , G) consisting of an invertible polynomial f and an abelian group G of its symmetries together with a dual pair (f ˜ , G ˜) . We consider the so-called orbifold E-function of such a pair (f , G) which is a generating function for the exponents of the monodromy action on an orbifold version of the mixed Hodge structure on the Milnor fibre of f. We prove that the orbifold E-functions of Berglund-Henningson dual pairs coincide up to a sign depending on the number of variables and a simple change of variables. The proof is based on a relation between monomials (say, elements of a monomial basis of the Milnor algebra of an invertible polynomial) and elements of the whole symmetry group of the dual polynomial.

  4. Inverted rank distributions: Macroscopic statistics, universality classes, and critical exponents

    NASA Astrophysics Data System (ADS)

    Eliazar, Iddo; Cohen, Morrel H.

    2014-01-01

    An inverted rank distribution is an infinite sequence of positive sizes ordered in a monotone increasing fashion. Interlacing together Lorenzian and oligarchic asymptotic analyses, we establish a macroscopic classification of inverted rank distributions into five “socioeconomic” universality classes: communism, socialism, criticality, feudalism, and absolute monarchy. We further establish that: (i) communism and socialism are analogous to a “disordered phase”, feudalism and absolute monarchy are analogous to an “ordered phase”, and criticality is the “phase transition” between order and disorder; (ii) the universality classes are characterized by two critical exponents, one governing the ordered phase, and the other governing the disordered phase; (iii) communism, criticality, and absolute monarchy are characterized by sharp exponent values, and are inherently deterministic; (iv) socialism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by continuous power-law statistics; (v) feudalism is characterized by a continuous exponent range, is inherently stochastic, and is universally governed by discrete exponential statistics. The results presented in this paper yield a universal macroscopic socioeconophysical perspective of inverted rank distributions.

  5. Fabrication and characterization of inverted organic solar cells using shuttle cock-type metal phthalocyanine and PCBM:P3HT

    SciTech Connect

    Suzuki, Atsushi Furukawa, Ryo Akiyama, Tsuyoshi Oku, Takeo

    2015-02-27

    Inverted organic solar cells using shuttle cock-type phthalocyanine, semiconducting polymer and fullerenes were fabricated and characterized. Photovoltaic and optical properties of the solar cells with inverted structures were investigated by optical absorption, current density-voltage characteristics. The photovoltaic properties of the tandem organic solar cell using titanyl phthalocyanine, vanadyl phthalocyanine, poly(3-hexylthiophene) (P3HT) and [6, 6]-phenyl C{sub 61}-butyric acid methyl ester (PCBM) were improved. Effect of annealing and solvent treatment on surface morphologies of the active layer was investigated. The photovoltaic mechanisms, energy levels and band gap of active layers were discussed for improvement of the photovoltaic performance.

  6. Air-stable n-type organic thin-film transistor array and high gain complementary inverter on flexible substrate

    NASA Astrophysics Data System (ADS)

    Fujisaki, Yoshihide; Nakajima, Yoshiki; Kumaki, Daisuke; Yamamoto, Toshihiro; Tokito, Shizuo; Kono, Takahiro; Nishida, Jun-ichi; Yamashita, Yoshiro

    2010-09-01

    Air-stable n-type organic thin-film transistor (TFT) arrays and a complementary inverter circuit were fabricated on a flexible substrate. A benzobis(thiadiazole) (BBT) derivative-based TFT showed excellent air- stability and performances such as an electron mobility of over 0.1 cm2/V s, a large ON/OFF ratio over 108 when combined with a cross-linkable olefin-type polymer gate dielectric. In addition, an organic complementary inverter that combined the BBT derivative and a pentacene TFT demonstrated a sharp switching behavior and a high gain of over 150. We attribute these excellent characteristics to a combination of the low-lying lowest unoccupied molecular orbital level of n-type semiconductor material and the low interface trap of the gate dielectric.

  7. Lithosphere thickness and mantle viscosity inverted from GPS-derived deformation rates in Fennoscandia

    NASA Astrophysics Data System (ADS)

    Zhao, S.; Lambeck, K.; Lidberg, M.

    2012-07-01

    Crustal deformation in Fennoscandia is associated with the glacial isostatic adjustment (GIA) process that is caused by ongoing stress release of the mantle after removal of the Late Pleistocene ice sheet by ˜10 cal ka BP. With an earth model of defined structure and rheology and an ice-sheet model of known melting history, the GIA process can be simulated by geophysical models, and the surface deformation rates can be calculated and used to compare with global positioning system (GPS) observations. Therefore, the crustal deformation rates observed by GPS in Fennoscandia provide constraints on the geophysical models. On the basis of two ice sheet models (ANU-ICE and ICE-5G) reconstructed independently by the Australian National University (ANU) and University of Toronto, we use the GPS-derived deformation rates to invert for lithosphere thickness and mantle viscosity in Fennoscandia. The results show that only a three-layer earth model can be resolved from current GPS data, providing robust estimates of effective lithosphere thickness, upper and lower mantle viscosity. The earth models estimated from inversion of GPS data with two different ice sheet models define a narrow range of parameter space: the lithosphere thickness between 93 and 110 km, upper mantle viscosity between 3.4 and 5.0 × 1020 Pa s, and lower mantle viscosity between 7 × 1021 and 13 × 1021 Pa s. The estimates are consistent with those inverted from relative sea-level indicators.

  8. Effective g-factors of carriers in inverted InAs/GaSb bilayers

    NASA Astrophysics Data System (ADS)

    Mu, Xiaoyang; Sullivan, Gerard; Du, Rui-Rui

    2016-01-01

    We perform tilt-field transport experiment on inverted InAs/GaSb, which hosts quantum spin Hall insulator. By means of coincidence method, Landau level (LL) spectra of electron and hole carriers are systematically studied at different carrier densities tuned by gate voltages. When Fermi level stays in the conduction band, we observe LL crossing and anti-crossing behaviors at odd and even filling factors, respectively, with a corresponding g-factor of 11.5. It remains nearly constant for varying filling factors and electron densities. On the contrary, for GaSb holes, only a small Zeeman splitting is observed even at large tilt angles, indicating a g-factor of less than 3.

  9. Too Much of a Good Thing: The Challenge and Opportunity of the Inverted U.

    PubMed

    Grant, Adam M; Schwartz, Barry

    2011-01-01

    Aristotle proposed that to achieve happiness and success, people should cultivate virtues at mean or intermediate levels between deficiencies and excesses. In stark contrast to this assertion that virtues have costs at high levels, a wealth of psychological research has focused on demonstrating the well-being and performance benefits of positive traits, states, and experiences. This focus has obscured the prevalence and importance of nonmonotonic inverted-U-shaped effects, whereby positive phenomena reach inflection points at which their effects turn negative. We trace the evidence for nonmonotonic effects in psychology and provide recommendations for conceptual and empirical progress. We conclude that for psychology in general and positive psychology in particular, Aristotle's idea of the mean may serve as a useful guide for developing both a descriptive and a prescriptive account of happiness and success. PMID:26162116

  10. Al-doping effects on the photovoltaic performance of inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Yu, Xuan; Shi, Ya-feng; Yu, Xiao-ming; Zhang, Jian-jun; Ge, Ya-ming; Chen, Li-qiao; Pan, Hong-jun

    2016-03-01

    The properties of Al-doped ZnO (AZO) play an important role in the photovoltaic performance of inverted polymer solar cells (PSCs), which is used as electron transport and hole blocking buffer layers. In this work, we study the effects of Al-doping level in AZO on device performance in detail. Results indicate that the device performance intensely depends on the Al-doping level. The AZO thin films with Al-doping atomic percentage of 1.0% possess the best conductivity. The resulting solar cells show the enhanced short current density and the fill factor ( FF) simultaneously, and the power conversion efficiency ( PCE) is improved by 74%, which are attributed to the reduced carrier recombination and the optimized charge transport and extraction between AZO and the active layer.

  11. New Switches for Utility-Scale Inverters: First In-Class Demonstration of a Completely New Type of SiC Bipolar Switch (15kV-20kV) for Utility-Scale Inverters

    SciTech Connect

    2011-12-31

    Solar ADEPT Project: The SiCLAB is developing a new power switch for utility-scale PV inverters that would improve the performance and significantly reduce the size, weight, and energy loss of PV systems. A power switch controls the electrical energy flowing through an inverter, which takes the electrical current from a PV solar panel and converts it into the type and amount of electricity that is compatible with the electric grid. SiCLAB is using silicon carbide (SiC) semiconductors in its new power switches, which are more efficient than the silicon semiconductors used to conduct electricity in most conventional power switches today. Switches with SiC semiconductors can operate at much higher temperatures, as well as higher voltage and power levels than silicon switches. SiC-based power switches are also smaller than those made with silicon alone, so they result in much smaller and lighter electrical devices. In addition to their use in utility-scale PV inverters, SiCLAB’s new power switches can also be used in wind turbines, railways, and other smart grid applications.

  12. Correlation between pretreatment serum LDL-cholesterol levels and prognosis in nasopharyngeal carcinoma patients

    PubMed Central

    Tang, Qiu; Hu, Qiao-Ying; Piao, Yong-feng; Hua, Yong-Hong

    2016-01-01

    Purpose To investigate the correlations between long-term survival outcomes in patients with nasopharyngeal carcinoma (NPC) and pretreatment serum low-density lipoprotein cholesterol (LDL-C) levels. Patients and methods Between January 2008 and December 2011, 935 patients with newly diagnosed NPC who were treated with intensity-modulated radiation therapy were included in this retrospective clinical analysis. Patients were divided into two groups based on pretreatment LDL-C levels: normal LDL-C (≤3.64 mmol/L; n=816) and elevated LDL-C (>3.64 mmol/L; n=119). Associations between pretreatment LDL-C levels and treatment outcome were analyzed by univariate and multivariate analyses. Results The overall patient follow-up rate was 95.1%, and 726 patients received more than 5 years of follow-up. Five-year overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) rates of the entire patient population were 87.1%, 91.1%, and 87.2%, respectively. Rates of 5-year OS, LC, and DMFS for the elevated versus normal LDL-C groups were 77.0% vs 89.1% (P<0.001), 85.8% vs 91.9% (P=0.041), and 81.1% vs 88.1% (P=0.038), respectively. Compared with normal LDL-C levels, elevated LDL-C levels were identified as an independent prognostic factor of a poorer OS (hazard ratio [HR] =2.171; 95% confidence interval [CI] =1.424–3.309), LC rate (HR =1.762; 95% CI =1.021–3.942), and DMFS (HR =1.594; 95% CI =1.003–2.532). Conclusion This study found that elevated pretreatment LDL-C levels are negative prognostic indicators of NPC. Elevated LDL-C levels may be useful indicators of locoregional control and distant metastasis in NPC patients. PMID:27217776

  13. Motor/Generator and Inverter Characterization for Flywheel System Applications

    NASA Technical Reports Server (NTRS)

    Tamarcus, Jeffries L.

    2004-01-01

    The Advanced Electrical Systems Development Branch at NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheels systems for satellite energy storage and attitude applications. These flywheels will serve as replacement for chemical nickel hydrogen, nickel cadmium batteries and gyroscopic wheels. The advantages of using flywheel systems for energy storage on satellites are high energy density, high power density, long life, deep depth of discharge, and broad operating temperature ranges. A flywheel system for space applications consist of a number of flywheel modules, the motor/generator and magnetic bearing, and an electronics package. The motor/generator electronics package includes a pulse-width modulated inverter that drives the flywheel permanent magnet motor/generator located at one end of the shaft. This summer, I worked under the direct supervision of my mentor, Walter Santiago, and the goal for this summer was to characterize motor generator and inverter attributes in order to increase their viability as a more efficient energy storage source for space applications. To achieve this goal, magnetic field measurements around the motor/generator permanent magnet and the impedance of the motor/generator three phase windings were characterized, and a recreation of the inverter pulse width modulated control system was constructed. The Flywheel modules for space use are designed to maximize energy density and minimize loss, and attaining these values will aid in locating and reducing losses within the flywheel system as a whole, making flywheel technology more attractive for use as energy storage in future space applications.

  14. Himalayan inverted metamorphism constrained by oxygen isotope thermometry

    NASA Astrophysics Data System (ADS)

    Vannay, Jean-Claude; Sharp, Zachary D.; Grasemann, Bernhard

    Inverted metamorphic field gradients are preserved in two amphibolite facies metapelitic sequences forming the crystalline core zone of the Himalayan orogen in the Sutlej valley (NW India). In the High Himalayan Crystalline Sequence (HHCS), metamorphic conditions increase upwards from the staurolite zone at the base, through the kyanite-in and sillimanite-in isograds, finally to reach partial melting conditions at the top. The structurally lower Lesser Himalayan Crystalline Sequence (LHCS) shows a gradual superposition of garnet-in, staurolite-in and kyanite+sillimanite-in isograds. Although phase equilibria constraints imply inverted temperature field gradients in both units, garnet-biotite (GARB) rim thermometry indicates final equilibration at a nearly uniform temperature around T 600°C across these sequences. The P-T path and garnet zoning data show that this apparent lack of thermal field gradient is mainly the consequence of a resetting of the GARB equilibria during cooling. In order to constrain peak temperature conditions, 20 samples along the studied section have been analysed for oxygen isotope thermometry. The isotopic fractionations recorded by quartz-garnet and quartz-aluminosilicate mineral pairs indicate temperatures consistent with phase equilibria and P-T path constraints for metamorphic peak conditions. Together with barometry results, based on net transfer continuous reactions, the oxygen isotope thermometry indicates peak conditions characterized by: (1) a temperature increase from T 570 to 750°C at a nearly constant pressure around P 800MPa, from the base to the top of the HHCS unit; (2) a temperature increase from T 610 to 700°C and a pressure decrease from P 900 to 700MPa, from the base to the top of the LHCS metapelites. Oxygen isotope thermometry thus provides the first quantitative data demonstrating that the Himalayan inverted metamorphism can be associated with a complete inversion of the thermal field gradient across the crystalline

  15. Daily Full-Disk SOLIS Inverted Vector Magnetic Field Data

    NASA Astrophysics Data System (ADS)

    Streander, Kim; Norton, A. A.; SOLIS Team

    2009-05-01

    Inverted vector magnetic field data from the SOLIS VSM (Synoptic Optical Long-term Investigations of the Sun Vector Spectromagnetograph) instrument are now available at:http://solis.nso.edu/. Both full-disk and smaller field-of-view data containing active regions are available. The inversion is based on the least-squares minimization FORTRAN code developed by the HAO group, initially used with Advanced Stokes Polarimeter data (Skumanich and Lites, 1987; Auer, Heasley and House, 1977). The main code modification is that a scattered light, or quiet-Sun profile, is simulated for every center-to-limb position on the disk. This simulated profile is used as the scattered light profile, instead of an observed profile averaged from pixels with low polarization within a small field of view. The data are inversions of Stokes I, Q, U and V profiles of the Fe I 630.1 and 630.2 nm lines using a Milne-Eddington (ME) model atmosphere. Stokes I, Q, U and V profile weights are 0.01, 1.0, 1.0 and 0.1, respectively. All the Milne-Eddington inverted data are corrected for the 180º ambiguity using the Non-Potential Field Calculation (NPFC) method developed by Manolis Georgoulis (Johns Hopkins). Note that data are only inverted if the observed polarization signal is above a certain threshold.Data are available daily (weather permitting) beginning April 1, 2009 onwards. Also available is a sample of data from March 2008 containing several active regions near the equator.

  16. Diagnostic agreement of conventional and inverted scanned panoramic radiographs in the detection of the mandibular canal and the mental foramen.

    PubMed

    Sakakura, Celso Eduardo; Loffredo, Leonor de Castro Monteiro; Scaf, Gulnara

    2004-01-01

    The aim of this study was to evaluate the diagnostic agreement of conventional panoramic radiographs and their inverted scanned images in the detection of the mandibular canal and mental foramen. A total of 77 panoramic radiographs obtained from the files of totally edentulous patients were used. Digitization was done by means of a scanner with brightness and contrast adjustment, as well as image inversion. The extension of mandibular canal was divided into anterior, middle, and posterior regions, and the presence of a radiopaque line that characterized the mandibular canal was classified according to a 5-point confidence scale. The mental foramen was classified in 4 types: continuous, separated, diffuse, and unidentified. Both conventional and inverted scanned panoramic radiographs were evaluated by 3 calibrated implantologists at 2 distinct moments with a minimum interval of 10 days between them. Intraexaminer agreement was evaluated by Kappa statistics by point and by 95% confidence interval. Because the intraexaminer level of agreement was low, interexaminer agreements could not be carried out. The results showed a substantial (in 2 situations), moderate (in 16 situations), and fair (in 18 situations) intraexaminer agreement for mandibular canal and a substantial (in 1 situation), fair (in 1 situation), and moderate (in 10 situations) intraeaminer agreement for mental foramen. There were no statistically significant differences in most instances. In conclusion, the diagnostic agreement of conventional and inverted scanned panoramic radiographs for detection of mandibular canal and mental foramen was low. PMID:15008448

  17. Mineralogy and petrology of lunar meteorite Northwest Africa 2977 consisting of olivine cumulate gabbro including inverted pigeonite

    NASA Astrophysics Data System (ADS)

    Nagaoka, Hiroshi; Karouji, Yuzuru; Takeda, Hiroshi; Fagan, Timothy J.; Ebihara, Mitsuru; Hasebe, Nobuyuki

    2015-12-01

    Lunar meteorite Northwest Africa (NWA) 2977 is identified as an olivine cumulate gabbro (OC), consisting of coarse cumulate olivine crystals up to 1 mm with low-Ca and high-Ca pyroxenes, plagioclase, and interstitial incompatible element-rich pockets of K-feldspar, Ca-phosphates, ilmenite, and troilite. These minerals and textures are similar to those of the OC clasts of the NWA 773 clan of meteorites. NWA 2977 contains a variety of pyroxene textures and compositions including augite, pigeonite, and rare orthopyroxene, all having exsolution lamellae. Some of the orthopyroxene has abundant augite lamellae with compositions indicating formation by inversion of pigeonite. This pigeonite was inverted at 1140 °C according to the pigeonite eutectoid reaction (PER) temperatures. Inverted pigeonite has not been found previously in the NWA 773 clan of meteorites. The presence of inverted pigeonite indicates that NWA 2977 cooled more slowly than most other OC clasts of the NWA 773 clan. The relatively slow cooling of NWA 2977 can be explained by formation in a deeper level of the original igneous body of the NWA 773 clan OC lithology.

  18. Extreme Cost Reductions with Multi-Megawatt Centralized Inverter Systems

    SciTech Connect

    Schwabe, Ulrich; Fishman, Oleg

    2015-03-20

    The objective of this project was to fully develop, demonstrate, and commercialize a new type of utility scale PV system. Based on patented technology, this includes the development of a truly centralized inverter system with capacities up to 100MW, and a high voltage, distributed harvesting approach. This system promises to greatly impact both the energy yield from large scale PV systems by reducing losses and increasing yield from mismatched arrays, as well as reduce overall system costs through very cost effective conversion and BOS cost reductions enabled by higher voltage operation.

  19. Separation of simple sugars by selectivity inverted parametric pumping

    SciTech Connect

    Sheng, P.; Costa, C.A.V.

    1998-12-01

    An alternative process to separate the isomeric mixture of fructose and glucose is presented. A laboratory study of a two-column, selectivity inverted, direct-mode parametric pump is reported. An anionic resin in carbonate form and a cationic resin in calcium form are used as adsorbents for the columns. The experimental results show that it is possible to simultaneously obtain separation and concentration with this system. A kinetic model assuming linear equilibrium, intraparticle pore diffusion, and axial dispersion is proposed and solved. The model solutions are compared with experimental results, and the comparisons indicate good prediction capabilities.

  20. Inverted Takotsubo cardiomyopathy after attempted suicidal hanging--two cases.

    PubMed

    Sengupta, Shantanu; Mungulmare, Kunda; Wadaskar, Nitin; Pande, Abhishek

    2016-04-01

    We report two cases of "Inverted Takotsubo cardiomyopathy" following attempted suicidal hanging. Both the patients presented with heart failure and had desaturation 8-12h after the suicidal attempt. Electrocardiography (ECG) showed ischemic changes. On echocardiography, the left ventricle (LV) showed ballooning and hypokinesia of the basal segments with apical sparing. Both patients underwent coronary angiograms considering the possibility of acute coronary syndrome. However, their coronary angiograms were normal. After 3-4 days of hospitalization, both recovered; their ECG had reversed and the LV contractility was normal on echocardiography. PMID:27056654

  1. Molecular solid-state inverter-converter system

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1973-01-01

    A modular approach for aerospace electrical systems has been developed, using lightweight high efficiency pulse width modulation techniques. With the modular approach, a required system is obtained by paralleling modules. The modular system includes the inverters and converters, a paralleling system, and an automatic control and fault-sensing protection system with a visual annunciator. The output is 150 V dc, or a low distortion three phase sine wave at 120 V, 400 Hz. Input power is unregulated 56 V dc. Each module is rated 2.5 kW or 3.6 kVA at 0.7 power factor.

  2. Displacement measurement system for inverters using computer micro-vision

    NASA Astrophysics Data System (ADS)

    Wu, Heng; Zhang, Xianmin; Gan, Jinqiang; Li, Hai; Ge, Peng

    2016-06-01

    We propose a practical system for noncontact displacement measurement of inverters using computer micro-vision at the sub-micron scale. The measuring method of the proposed system is based on a fast template matching algorithm with an optical microscopy. A laser interferometer measurement (LIM) system is built up for comparison. Experimental results demonstrate that the proposed system can achieve the same performance as the LIM system but shows a higher operability and stability. The measuring accuracy is 0.283 μm.

  3. Naturally Inspired Firefly Controller For Stabilization Of Double Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Srikanth, Kavirayani; Nagesh, Gundavarapu

    2015-12-01

    A double inverted pendulum plant as an established model that is analyzed as part of this work was tested under the influence of time delay, where the controller was fine tuned using a firefly algorithm taking into considering the fitness function of variation of the cart position and to minimize the cart position displacement and still stabilize it effectively. The naturally inspired algorithm which imitates the fireflies definitely is an energy efficient method owing to the inherent logic of the way the fireflies respond collectively and has shown that critical time delays makes the system healthy.

  4. Design and analysis of controllers for a double inverted pendulum.

    PubMed

    Niemann, Henrik; Poulsen, Jesper Kildegaard

    2005-01-01

    A physical control problem is studied with the Hinfinity, and the micro methodology. The issues of modeling, uncertainty modeling, performance specification, controller design, and laboratory implementation are discussed. The laboratory experiment is a double inverted pendulum placed on a cart. The limitations in the system with respect to performance are the limitation in the control signal and the limitation of the movement of the cart. It is shown how these performance limitations will effect the design of Hinfinity and micro controllers for the system. PMID:15682623

  5. Characterization of the Ecosole HCPV tracker and single module inverter

    NASA Astrophysics Data System (ADS)

    Carpanelli, Maurizio; Borelli, Gianni; Verdilio, Daniele; De Nardis, Davide; Migali, Fabrizio; Cancro, Carmine; Graditi, Giorgio

    2015-09-01

    BECAR, the Beghelli group's R&D company, is leading ECOSOLE (Elevated COncentration SOlar Energy), one of the largest European Demonstration projects in solar photovoltaic. ECOSOLE, started in 2012, is focused on the study, design, and realization of new HCPV generator made of high efficiency PV modules equipped with SoG (Silicone on Glass) fresnel lenses and III-V solar cells, and a low cost matched solar tracker with distributed inverters approach. The project also regards the study and demonstration of new high throughput methods for the industrial large scale productions, at very low manufacturing costs. This work reports the description of the characterization of the tracker and single module.

  6. Robust sliding mode control applied to double Inverted pendulum system

    SciTech Connect

    Mahjoub, Sonia; Derbel, Nabil; Mnif, Faical

    2009-03-05

    A three hierarchical sliding mode control is presented for a class of an underactuated system which can overcome the mismatched perturbations. The considered underactuated system is a double inverted pendulum (DIP), can be modeled by three subsystems. Such structure allows the construction of several designs of hierarchies for the controller. For all hierarchical designs, the asymptotic stability of every layer sliding mode surface and the sliding mode surface of subsystems are proved theoretically by Barbalat's lemma. Simulation results show the validity of these methods.

  7. Utility-scale grid-tied PV inverter reliability workshop summary report.

    SciTech Connect

    Granata, Jennifer E.; Quintana, Michael A.; Tasca, Coryne Adelle; Atcitty, Stanley

    2011-07-01

    A key to the long-term success of the photovoltaic (PV) industry is confidence in the reliability of PV systems. Inverters are the most commonly noted cause of PV system incidents triggered in the field. While not all of these incidents are reliability-related or even necessarily failures, they still result in a loss of generated power. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a Utility-Scale Grid-Tied Inverter Reliability Workshop in Albuquerque, New Mexico, January 27-28, 2011. The workshop addressed the reliability of large (100-kilowatt+) grid-tied inverters and the implications when such inverters fail, evaluated inverter codes and standards, and provided discussion about opportunities to enhance inverter reliability. This report summarizes discussions and presentations from the workshop and identifies opportunities for future efforts.

  8. High-speed all-optical logic inverter based on stimulated Raman scattering in silicon nanocrystal.

    PubMed

    Sen, Mrinal; Das, Mukul K

    2015-11-01

    In this paper, we propose a new device architecture for an all-optical logic inverter (NOT gate), which is cascadable with a similar device. The inverter is based on stimulated Raman scattering in silicon nanocrystal waveguides, which are embedded in a silicon photonic crystal structure. The Raman response function of silicon nanocrystal is evaluated to explore the transfer characteristic of the inverter. A maximum product criterion for the noise margin is taken to analyze the cascadability of the inverter. The time domain response of the inverter, which explores successful inversion operation at 100 Gb/s, is analyzed. Propagation delay of the inverter is on the order of 5 ps, which is less than the delay in most of the electronic logic families as of today. Overall dimension of the device is around 755  μm ×15  μm, which ensures integration compatibility with the matured silicon industry. PMID:26560565

  9. Evaluation of quasi-square wave inverter as a power source for induction motors

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Haggard, R. L.; Lanier, J. R., Jr.

    1977-01-01

    The relative merits of quasi-square wave inverter-motor technology versus a sine wave inverter-motor system were investigated. The empirical results of several tests on various sizes of wye-wound induction motors are presented with mathematical analysis to support the conclusions of the study. It was concluded that, within the limitations presented, the quasi-square wave inverter-motor system is superior to the more complex sine wave system for most induction motor applications in space.

  10. Examining cemented inverted channel deposits in Green River, Utah as an analog for inverted terrain on Mars

    NASA Astrophysics Data System (ADS)

    Lanza, N.; Okubo, C. H.; Rampe, E. B.; Ollila, A. M.; Newsom, H. E.; Yurchyk, S.

    2009-12-01

    There have been numerous observations of long, relatively sinuous, positive relief landforms on Mars that appear morphologically similar to inverted channel deposits (ICDs) on Earth that represent exhumed fluvial sediments. ICDs initially form as bed sediments within active stream channels that subsequently become cemented, commonly by carbonates, iron oxides, or amorphous silica precipitated during evaporation. Subsequent deflation by aeolian processes reveals these sediments as positive relief features. Features such as the putative delta system in Eberswalde crater and the sinuous ridge in Miyamoto crater appear morphologically similar to terrestrial ICDs. The goal of this study is to better understand how terrestrial ICDs appear to remote sensing instruments that are similar to the ones currently orbiting Mars, and whether they have morphologic or spectroscopic characteristics that could help to identify them from orbit as paleofluvial deposits. Specifically, the presence of cement materials in conjunction with inverted terrain may help to identify potential ICDs on Mars. While carbonate is an unlikely cementing agent on Mars, both iron oxide and amorphous silica have been observed there. A terrestrial analog may be found in ICDs in the Cedar Mountain formation in Green River, Utah. Preliminary electron microprobe results indicate that the cement in these ICDs is primarily an amorphous silica (chalcedony) rather than a carbonate. If some martian inverted features are similarly cemented, they may not initially appear to be sedimentary features in infrared (IR) spectroscopy remote sensing data, especially if their constituent sediments are basaltic. We will show results from our initial laboratory examination of terrestrial ICD samples in mid-IR emission spectroscopy and compare these with remote sensing data of these ICDs in a similar band range from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to identify features characteristic of

  11. CUORE and Beyond: Bolometric Techniques to Explore Inverted Neutrino Mass Hierarchy

    NASA Astrophysics Data System (ADS)

    Artusa, D. R.; Avignone, F. T.; Azzolini, O.; Balata, M.; Banks, T. I.; Bari, G.; Beeman, J.; Bellini, F.; Bersani, A.; Biassoni, M.; Brofferio, C.; Bucci, C.; Cai, X. Z.; Camacho, A.; Canonica, L.; Cao, X. G.; Capelli, S.; Carbone, L.; Cardani, L.; Carrettoni, M.; Casali, N.; Chiesa, D.; Chott, N.; Clemenza, M.; Copello, S.; Cosmelli, C.; Cremonesi, O.; Creswick, R. J.; Dafinei, I.; Dally, A.; Datskov, V.; De Biasi, A.; Deninno, M. M.; Di Domizio, S.; di Vacri, M. L.; Ejzak, L.; Fang, D. Q.; Farach, H. A.; Faverzani, M.; Fernandes, G.; Ferri, E.; Ferroni, F.; Fiorini, E.; Franceschi, M. A.; Freedman, S. J.; Fujikawa, B. K.; Giachero, A.; Gironi, L.; Giuliani, A.; Goett, J.; Gorla, P.; Gotti, C.; Gutierrez, T. D.; Haller, E. E.; Han, K.; Heeger, K. M.; Hennings-Yeomans, R.; Huang, H. Z.; Kadel, R.; Kazkaz, K.; Keppel, G.; Kolomensky, Yu. G.; Li, Y. L.; Ligi, C.; Liu, X.; Ma, Y. G.; Maiano, C.; Maino, M.; Martinez, M.; Maruyama, R. H.; Mei, Y.; Moggi, N.; Morganti, S.; Napolitano, T.; Nisi, S.; Nones, C.; Norman, E. B.; Nucciotti, A.; O'Donnell, T.; Orio, F.; Orlandi, D.; Ouellet, J. L.; Pallavicini, M.; Palmieri, V.; Pattavina, L.; Pavan, M.; Pedretti, M.; Pessina, G.; Pettinacci, V.; Piperno, G.; Pira, C.; Pirro, S.; Previtali, E.; Rampazzo, V.; Rosenfeld, C.; Rusconi, C.; Sala, E.; Sangiorgio, S.; Scielzo, N. D.; Sisti, M.; Smith, A. R.; Taffarello, L.; Tenconi, M.; Terranova, F.; Tian, W. D.; Tomei, C.; Trentalange, S.; Ventura, G.; Vignati, M.; Wang, B. S.; Wang, H. W.; Wielgus, L.; Wilson, J.; Winslow, L. A.; Wise, T.; Woodcraft, A.; Zanotti, L.; Zarra, C.; Zhu, B. X.; Zucchelli, S.

    The CUORE (Cryogenic Underground Observatory for Rare Events) experiment will search for neutrinoless double beta decay of 130Te. With 741 kg of TeO2 crystals and an excellent energy resolution of 5 keV (0.2%) at the region of interest, CUORE will be one of the most competitive neutrinoless double beta decay experiments on the horizon. With five years of live time, CUORE projected neutrinoless double beta decay half-life sensitivity is 1.6 × 1026 y at 1σ (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40-100 meV (50-130 meV). Further background rejection with auxiliary light detector can significantly improve the search sensitivity and competitiveness of bolometric detectors to fully explore the inverted neutrino mass hierarchy with 130Te and possibly other double beta decay candidate nuclei.

  12. Double dark resonance in inverted Y system and its application in attenuating the optical switching action

    NASA Astrophysics Data System (ADS)

    Ali, Sabir; Ray, Ayan; Chakrabarti, Alok

    2016-02-01

    Electromagnetically Induced Transparency as a novel type optical memory has gained enough attention in the field of research related to optical communication. This kind of transparency is an artificially created spectral window used to slow and spatially compress light pulses. Hence controlling and manipulation of such transparency window in a multilevel atom-photon system will, in turn, help in opening newer avenues of applications. In the present work an inverted Y linkage (established in the 5S1/2 → 5P3/2 → 5D5/2 hyperfine levels of 87Rb atom) is used for this purpose. The formation of matched double dark resonance in the system has been studied in details. On the application front we have demonstrated using the system as an attenuator of optical switch. This type of necessity may arise for futuristic optical communication system. Overall the system response resembles the performance of a combination logic gate.

  13. Multiple output power supply circuit for an ion engine with shared upper inverter

    NASA Technical Reports Server (NTRS)

    Cardwell, Jr., Gilbert I. (Inventor); Phelps, Thomas K. (Inventor)

    2001-01-01

    A power supply circuit for an ion engine suitable for a spacecraft is coupled to a bus having a bus input and a bus return. The power supply circuit has a first primary winding of a first transformer. An upper inverter circuit is coupled to the bus input and the first primary winding. The power supply circuit further includes a first lower inverter circuit coupled to the bus return and the first primary winding. The second primary winding of a second transformer is coupled to the upper inverter circuit. A second lower inverter circuit is coupled to the bus return and the second primary winding.

  14. [Effect of the interphase surface charge on the structure and activity of trypsin in inverted micelles].

    PubMed

    Valiullina, Iu A; Stupishina, E A; Vylegzhanina, N N; Idiiatullin, B Z; Zuev, Iu F

    2008-01-01

    The effect of the sign and value of the charge of the interphase surface on the catalytic activity of trypsin in systems of inverted mycelles was investigated. n-Butanol was used for the modification of the phase interface in dispersions of inverted mycelles based on anionic sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and cationic cetyltrimethylammonium bromide (CTAB). A direct correlation between changes in the state of inverted mycelles and the structure of solubilized enzyme under the action of butanol was obtained. It was shown that the enzyme activity is determined by the quantity of butanol solubilized by the inverted mycelles. PMID:18672691

  15. Amphoteric water-in-oil self-inverting polymer emulsion

    SciTech Connect

    Lipowski, S. A.; Miskel Jr., J. J.

    1985-03-19

    An amphoteric water-in-oil self-inverting polymer emulsion is prepared which contains a copolymer of a nonionic vinyl monomer and an amphoteric vinyl monomer or a terpolymer of (1) a nonionic vinyl monomer, an anionic vinyl monomer and a cationic vinyl monomer in the aqueous phase, a hydrocarbon oil for the oil phase, a water-in-oil emulsifying agent and an inverting surfactant. An example of a copolymer is a copolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide and an amphoteric vinyl monomer such as a reaction product of dimethylaminoethyl methacrylate and monochloroacetic acid. An example of a terpolymer is a terpolymer of a nonionic vinyl monomer such as acrylamide or methacrylamide, an anionic vinyl monomer such as sodium acrylate and a cationic vinyl monomer such as a triethyl ammonium ethyl methacrylate methosulfate salt. The emulsion is useful in papermaking, treatment of sewage and industrial wastes, drilling muds and secondary and tertiary recovery of petroleum by water flooding.

  16. Liking versus Complexity: Decomposing the Inverted U-curve

    PubMed Central

    Güçlütürk, Yağmur; Jacobs, Richard H. A. H.; van Lier, Rob

    2016-01-01

    The relationship between liking and stimulus complexity is commonly reported to follow an inverted U-curve. However, large individual differences among complexity preferences of participants have frequently been observed since the earliest studies on the topic. The common use of across-participant analysis methods that ignore these large individual differences in aesthetic preferences gives an impression of high agreement between individuals. In this study, we collected ratings of liking and perceived complexity from 30 participants for a set of digitally generated grayscale images. In addition, we calculated an objective measure of complexity for each image. Our results reveal that the inverted U-curve relationship between liking and stimulus complexity comes about as the combination of different individual liking functions. Specifically, after automatically clustering the participants based on their liking ratings, we determined that one group of participants in our sample had increasingly lower liking ratings for increasingly more complex stimuli, while a second group of participants had increasingly higher liking ratings for increasingly more complex stimuli. Based on our findings, we call for a focus on the individual differences in aesthetic preferences, adoption of alternative analysis methods that would account for these differences and a re-evaluation of established rules of human aesthetic preferences. PMID:27047359

  17. Unstable high molecular weight inverted repetitive DNA in human lymphocytes.

    PubMed Central

    Rogers, J C; Rucinsky, T E

    1982-01-01

    About 1% of newly synthesized DNA from PHA-stimulated human lymphocytes can be isolated as large (up to 90 kilobase pairs) double stranded fragments that resist sequential alkali and heat denaturation steps but are not closed circular. By electron microscopy about 1% have single-strand hairpin loops at one end and therefore present inverted repetitive sequences (IR-DNA). Most of the remainder have a blunt-appearing double-strand terminus at both ends (78%) or one end (18%). Indirect evidence indicates that these also are inverted complementary structures with terminal hairpin loops too small to be visualized: (1) Treatment with either a 5' or 3' single-strand exonuclease generates essentially only fragments with a single strand at one end; (2) with partial denaturation, the number of fragments with identifiable single-strand hairpin loops increases (to about 20%); (3) after S1 nuclease digestion, greater than 95% can be fully heat denatured. Cot analysis indicates that these fragments are derived from dispersed sites throughout the genome. Up to 25% of DNA released from lymphocytes during growth similarly resists denaturation, and released DNA and IR-DNA are both enriched in the same set of repetitive sequences. Thus at least a portion of IR-DNA appears to be unstable. Images PMID:7145706

  18. The management of sinonasal inverted papilloma: our experience.

    PubMed

    Terzakis, Georgios; Vlachou, Stamatia; Kyrmizakis, Dionysios; Helidonis, Emmanuel

    2002-03-01

    The inverted papilloma of the nose and paranasal sinuses is a controversial disease. It invades surrounded structures, shows a high recurrence rate after surgical excision and may coexist with squamous cell carcinoma. The use of the optimal surgical approach and technique is of the utmost importance, as it is related to the possibility of recurrence. In cases of tumors of limited size a conservative local excision is sufficient, while, in larger tumors filling the nasal cavity and the paranasal sinuses a more aggressive strategy is needed, such as a medial maxillectomy after lateral rhinotomy. In this paper we present our experience from treating 42 sinonasal inverted papillomas, using a surgical technique which is based on the conservation of as much part of the healthy lateral nasal wall as possible. This modified medial maxillectomy allows us to create a limited in size and normally functioning nasal cavity, thus minimizing the disadvantages of the classical medial maxillectomy without jeopardizing the safety of the operation. PMID:12012951

  19. Fast face recognition by using an inverted index

    NASA Astrophysics Data System (ADS)

    Herrmann, Christian; Beyerer, Jürgen

    2015-02-01

    This contribution addresses the task of searching for faces in large video datasets. Despite vast progress in the field, face recognition remains a challenge for uncontrolled large scale applications like searching for persons in surveillance footage or internet videos. While current productive systems focus on the best shot approach, where only one representative frame from a given face track is selected, thus sacrificing recognition performance, systems achieving state-of-the-art recognition performance, like the recently published DeepFace, ignore recognition speed, which makes them impractical for large scale applications. We suggest a set of measures to address the problem. First, considering the feature location allows collecting the extracted features in according sets. Secondly, the inverted index approach, which became popular in the area of image retrieval, is applied to these feature sets. A face track is thus described by a set of local indexed visual words which enables a fast search. This way, all information from a face track is collected which allows better recognition performance than best shot approaches and the inverted index permits constantly high recognition speeds. Evaluation on a dataset of several thousand videos shows the validity of the proposed approach.

  20. On the wake dynamics of flapping inverted flags

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Sotiropoulos, Fotis; Cosse, Julia; Gharib, Mory

    2014-11-01

    As recently shown experimentally by Kim et al. (JFM, 2013), when a flexible flag with a fixed trailing edge (an inverted flag) is exposed to a uniform inflow it can exhibit complex structural response and rich fluid-structure interaction (FSI) dynamics. We employ a new FSI numerical method to carry out large-eddy simulation (LES) of inverted flags in the range where large-amplitude flapping instabilities have been found experimentally. The numerical method integrates the curvilinear immersed boundary (CURVIB) FSI method of Borazjani et al. (JCP, 2008) with the thin-shell, rotation-free, finite-element (FE) formulation of Stolarski et al. (Int. JNME, 2013) and is able to simulate FSI of flexible thin bodies undergoing oscillations of arbitrarily large amplitude. The dynamic Smagorinsky model is employed for subgrid scale closure and a wall model is employed for reconstructing velocity boundary conditions. Comparisons with the experimental data show that the simulations are able to capture the structural response of the flag with very good accuracy. The computed results are analyzed to elucidate the structure and dynamics of the massively separated, unsteady flow shed off the flag edges. This work is supported by the US Department of Energy and the Minnesota Supercomputing Institute.

  1. Improved Tunnel-FET inverter performance with SiGe/Si heterostructure nanowire TFETs by reduction of ambipolarity

    NASA Astrophysics Data System (ADS)

    Richter, S.; Trellenkamp, S.; Schäfer, A.; Hartmann, J. M.; Bourdelle, K. K.; Zhao, Q. T.; Mantl, S.

    2015-06-01

    Complementary MOSFET and Tunnel-FET inverters based on tri-gated strained Si nanowire arrays are demonstrated. The voltage transfer characteristics as well as the inverter supply currents of both inverter types are analyzed and compared. A degradation of the inverter output voltage is observed due to the ambipolar transfer characteristics of the symmetric homostructure TFET devices. Emulated TFET inverters based on the measured transfer characteristics of SiGe/Si heterostructure nanowire array n-channel TFETs with reduced ambipolarity demonstrate improved inverter switching for supply voltages down to VDD = 0.2 V.

  2. An investigation of positive and inverted hemodynamic response functions across multiple visual areas

    PubMed Central

    Puckett, Alexander M.; Mathis, Jedidiah R.; DeYoe, Edgar A.

    2014-01-01

    Recent studies have demonstrated significant regional variability in the hemodynamic response function (HRF), highlighting the difficulty of correctly interpreting functional MRI (fMRI) data without proper modeling of the HRF. The focus of this study was to investigate the HRF variability within visual cortex. The HRF was estimated for a number of cortical visual areas by deconvolution of fMRI blood oxygenation level dependent (BOLD) responses to brief, large-field visual stimulation. Significant HRF variation was found across visual areas V1, V2, V3, V4, VO-1,2, V3AB, IPS-0,1,2,3, LO-1,2, and TO-1,2. Additionally, a subpopulation of voxels was identified that exhibited an impulse response waveform that was similar, but not identical, to an inverted version of the commonly described and modeled positive HRF. These voxels were found within the retinotopic confines of the stimulus and were intermixed with those showing positive responses. The spatial distribution and variability of these HRFs suggest a vascular origin for the inverted waveforms. We suggest that the polarity of the HRF is a separate factor that is independent of the suppressive or activating nature of the underlying neuronal activity. Correctly modeling the polarity of the HRF allows one to recover an estimate of the underlying neuronal activity rather than discard the responses from these voxels on the assumption that they are artifactual. We demonstrate this approach on phase-encoded retinotopic mapping data as an example of the benefits of accurately modeling the HRF during the analysis of fMRI data. PMID:25044672

  3. Single phase inverter for a three phase power generation and distribution system

    NASA Technical Reports Server (NTRS)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  4. Evaluation tests of Abacus 6 kVA utility-interactive inverter

    NASA Astrophysics Data System (ADS)

    Landsman, E. E.

    1981-08-01

    The voltage pattern spectra were analyzed for 100% and 50% pattern ratios and harmonics analyses are provided for the Abacus inverter. The harmonics are compared with those calculated for a simple model with no agreement. AC waveforms and inverter current spectra are given as well as basic electrical data.

  5. Evaluation tests of Abacus 6 kVA utility-interactive inverter

    SciTech Connect

    Landsman, E.E.

    1981-08-01

    The voltage pattern spectra were analyzed for 100% and 50% pattern ratios and harmonics analyses are provided for the Abacus inverter. The harmonics are compared with those calculated for a simple model with no agreement. AC waveforms and inverter current spectra are given as well as basic electrical data. (LEW)

  6. Vortex dynamics and flapping patterns of the inverted flag with a bluff body

    NASA Astrophysics Data System (ADS)

    Kim, Hyeonseong; Kim, Junyoung; Kim, Daegyoum

    2015-11-01

    Flow-induced vibration of flexible structures for energy harvesting has drawn attention recently. The inverted flag whose trailing edge is clamped and leading edge is free to move was known to self-excite in a uniform flow of both water and air. In this study, we investigated the effect of an upstream bluff body, a flat plate, on the dynamics of the downstream inverted flag. Periodic vortical structures created by an upstream bluff body make the dynamics of the inverted flag quite different from those of the inverted flag without the bluff body. We examined the motion of the inverted flag by varying the relative displacement of the inverted flag from the bluff body and their relative size. Our results show that the inverted flag can flap with higher frequency and larger amplitude with the upstream bluff body. We also compared the dynamics of the inverted flag with those of the general flag with the upstream bluff body. In order to better understand the dynamics of the flag, the analysis of the flow patterns using particle image velocimetry was also conducted.

  7. Inverting Instruction in Literacy Methods Courses: Making Learning More Active and Personalized

    ERIC Educational Resources Information Center

    Zawilinski, Lisa M.; Richard, Kimberly A.; Henry, Laurie A.

    2016-01-01

    Three teacher educators who inverted/flipped instruction in their literacy courses describe their experience in this article. Inverted, or flipped, instruction is a blended learning approach that increases opportunities for active engagement in class by moving basic instructor demonstration and presentation outside of class. The authors provide a…

  8. Inverting the Classroom: A Gateway to Creating an Inclusive Learning Environment.

    ERIC Educational Resources Information Center

    Lage, Maureen J.; Platt, Glenn J.; Treglia, Michael

    2000-01-01

    Describes a teaching strategy called the inverted classroom that enables instructors of introductory economics courses to address students' different learning styles within the time constraints of the class. Explains that in the inverted classroom the events that traditionally take place during class time now take place outside the classroom and…

  9. Design of An Inverted Magnetron Gun for a High Power Gyroklystron

    NASA Astrophysics Data System (ADS)

    Read, Michael E.; Nusinovich, Gregory; Ives, R. Lawrence

    2003-12-01

    A magnetron injection gun (MIG) with an inverted geometry is described. Use of an inverted geometry with the inner electrode at ground potential provides support for the inner coax portion of the cavities of a high power gyroklystron, and results in improved optics. The geometry of the gun is described and results of trajectory simulations are presented.

  10. Status and Needs of Power Electronics for Photovoltaic Inverters: Summary Document

    SciTech Connect

    WEST, RICK; MAUCH, KONRAD; QIN,YU CHIN; MOHAN,NED; BONN, RUSSELL H.

    2002-04-01

    Photovoltaic inverters are the most mature of any DER inverter, and their mean time to first failure (MTFF) is about five years. This is an unacceptable MTFF and will inhibit the rapid expansion of PV. With all DER technologies, (solar, wind, fuel cells, and microturbines) the inverter is still an immature product that will result in reliability problems in fielded systems. The increasing need for all of these technologies to have a reliable inverter provides a unique opportunity to address these needs with focused R&D development projects. The requirements for these inverters are so similar that modular designs with universal features are obviously the best solution for a ''next generation'' inverter. A ''next generation'' inverter will have improved performance, higher reliability, and improved profitability. Sandia National Laboratories has estimated that the development of a ''next generation'' inverter could require approximately 20 man-years of work over an 18- to 24-month time frame, and that a government-industry partnership will greatly improve the chances of success.

  11. Inverted Teaching: Applying a New Pedagogy to a University Organic Chemistry Class

    ERIC Educational Resources Information Center

    Christiansen, Michael A.

    2014-01-01

    Inverted teaching, not to be confused with hybrid learning, is a relatively new pedagogy in which lecture is shifted outside of class and traditional homework is done in class. Though some inverted teaching (IT) designs have been published in different fields, peer-reviewed reports in university chemistry remain quite rare. To that end, herein is…

  12. Expression analysis for inverted effects of serotonin transporter inactivation

    SciTech Connect

    Ichikawa, Manabu |; Okamura-Oho, Yuko Shimokawa, Kazuro; Kondo, Shinji; Nakamura, Sakiko; Yokota, Hideo |; Himeno, Ryutaro; Lesch, Klaus-Peter; Hayashizaki, Yoshihide |

    2008-03-28

    Inactivation of serotonin transporter (HTT) by pharmacologically in the neonate or genetically increases risk for depression in adulthood, whereas pharmacological inhibition of HTT ameliorates symptoms in depressed patients. The differing role of HTT function during early development and in adult brain plasticity in causing or reversing depression remains an unexplained paradox. To address this we profiled the gene expression of adult Htt knockout (Htt KO) mice and HTT inhibitor-treated mice. Inverted profile changes between the two experimental conditions were seen in 30 genes. Consistent results of the upstream regulatory element search and the co-localization search of these genes indicated that the regulation may be executed by Pax5, Pax7 and Gata3, known to be involved in the survival, proliferation, and migration of serotonergic neurons in the developing brain, and these factors are supposed to keep functioning to regulate downstream genes related to serotonin system in the adult brain.

  13. Position and Orientation Control of a Wheeled Inverted Pendulum

    NASA Astrophysics Data System (ADS)

    Ozaki, Hiroaki; Ohgushi, Takahiro; Shimogawa, Tetsuji; Lin, Chang-Jun

    A wheeled inverted pendulum (WIP), which is unstable, nonholonomic, and has two servo-driven wheels, is fabricated and used to confirm the proposed method for controlling its position and orientation. First, a WIP control system equipped with sensors such as a piezoelectric gyro to detect the tilt angle and two semiconductor photosensing devices to detect the position and orientation, is constructed. By using a distance variable, the system dynamics is decoupled and an optimal regulator with integral action is constructed to reduce the influence of disturbances. Algorithms are proposed to cope with the singularity problem included in the feedback control. Finally, the WIP is effectively controlled starting from various initial positions and orientations to a specified final state.

  14. Alpha detection in pipes using an inverting membrane scintillator

    SciTech Connect

    Kendrick, D.T.; Cremer, C.D.; Lowry, W.

    1995-10-01

    Characterization of surface alpha emitting contamination inside enclosed spaces such as piping systems presents an interesting radiological measurement challenge. Detection of these alpha particles from the exterior of the pipe is impossible since the alpha particles are completely absorbed by the pipe wall. Traditional survey techniques, using hand-held instruments, simply can not be used effectively inside pipes. Science and Engineering Associates, Inc. is currently developing an enhancement to its Pipe Explorer{trademark} system that will address this challenge. The Pipe Explorer{trademark} uses a unique sensor deployment method where an inverted tubular membrane is propagated through complex pipe runs via air pressure. The inversion process causes the membrane to fold out against the pipe wall, such that no part of the membrane drags along the pipe wall. This deployment methodology has been successfully demonstrated at several DOE sites to transport specially designed beta and gamma, scintillation detectors into pipes ranging in length up to 250 ft.

  15. Integrated Ring Oscillators based on high-performance Graphene Inverters

    PubMed Central

    Schall, Daniel; Otto, Martin; Neumaier, Daniel; Kurz, Heinrich

    2013-01-01

    The road to the realization of complex integrated circuits based on graphene remains an open issue so far. Current graphene based integrated circuits are limited by low integration depth and significant doping variations, representing major road blocks for the success of graphene in future electronic devices. Here we report on the realization of graphene based integrated inverters and ring oscillators. By using an optimized process technology for high-performance graphene transistors with local back-gate electrodes we demonstrate that complex graphene based integrated circuits can be manufactured reproducibly, circumventing problems associated with doping variations. The fabrication process developed here is scalable and fully compatible with conventional silicon technology. Therefore, our results pave the way towards applications based on graphene transistors in future electronic devices. PMID:24005257

  16. Complexity of regular invertible p-adic motions.

    PubMed

    Pettigrew, J.; Roberts, J. A. G.; Vivaldi, F.

    2001-12-01

    We consider issues of computational complexity that arise in the study of quasi-periodic motions (Siegel discs) over the p-adic integers, where p is a prime number. These systems generate regular invertible dynamics over the integers modulo p(k), for all k, and the main questions concern the computation of periods and orbit structure. For a specific family of polynomial maps, we identify conditions under which the cycle structure is determined solely by the number of Siegel discs and two integer parameters for each disc. We conjecture the minimal parametrization needed to achieve-for every odd prime p-a two-disc tessellation with maximal cycle length. We discuss the relevance of Cebotarev's density theorem to the probabilistic description of these dynamical systems. (c) 2001 American Institute of Physics. PMID:12779524

  17. Phase synchronized quasiperiodicity in power electronic inverter systems

    NASA Astrophysics Data System (ADS)

    Zhusubaliyev, Zhanybai T.; Mosekilde, Erik; Andriyanov, Alexey I.; Shein, Vladimir V.

    2014-02-01

    The development of switch-mode operated power electronic converter systems has provided a broad range of new effective approaches to the conversion of electric power. In this paper we describe the transitions from regular periodic operation to quasiperiodicity and high-periodic resonance behavior that can be observed in a pulse-width modulated DC/AC converter operating with high feedback gain. We demonstrate the occurrence of two different types of torus birth bifurcations and present a series of phase portraits illustrating the appearance of phase-synchronized quasiperiodicity. Our numerical findings are verified through comparison with an experimental inverter system. The results shed light on the transitions to quasiperiodicity and to various forms of three-frequency dynamics in non-smooth systems.

  18. Low voltage drop plasma switch for inverter and modulator applications

    NASA Astrophysics Data System (ADS)

    Goebel, D. M.; Poeschel, R. L.; Schumacher, R. W.

    1993-08-01

    A low forward voltage drop plasma switch has been developed for high-efficiency inverter and modulator applications. The switch, called the HOLLOTRON, is based on a grid-controlled, thermionic hollow-cathode discharge. A low forward voltage drop (10-20 V) is achieved by operating the hollow-cathode discharge in a static gas pressure of xenon. The dense plasma generated in the Ba-oxide dispenser hollow cathode is spread over a relatively large control grid area by a diverging magnetic field superimposed on the discharge. Interruption of the discharge current at high current densities (≳4 A/cm2) over the grid area is achieved by biasing the control grid sufficiently negative with respect to the plasma. The HOLLOTRON switch has demonstrated voltage stand-off of up to 20 kV, switching times of ≤0.3 μs, and pulse repetition frequencies of 20 kHz at 50% duty.

  19. An Inverted Co-Flow Diffusion Flame for Producing Soot

    SciTech Connect

    Stipe, Christopher B.; Higgins, Brian S.; Lucas, Donald; Koshland, Catherine P.; Sawyer, Robert F.

    2005-06-21

    We developed an inverted, co-flow, methane/air/nitrogen burner that generates a wide range of soot particles sizes and concentrations. By adjusting the flow rates of air, methane, and nitrogen in the fuel, the mean electric mobility diameter and number concentration are varied. Additional dilution downstream of the flame allows us to generate particle concentrations spanning those produced by spark-ignited and diesel engines: particles with mean diameters between 50 and 250 nm and number concentrations from 4.7 {center_dot} 10{sup 4} to 10{sup 7} cm{sup -3}. The range of achievable number concentrations, and therefore volume concentrations, can be increased by a factor of 30 by reducing the dilution ratio. These operating conditions make this burner valuable for developing and calibrating diagnostics as well as for other studies involving soot particles.

  20. EV drivetrain inverter with V/HZ optimization

    DOEpatents

    Gritter, David J.; O'Neil, Walter K.

    1986-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer which calculates optimized machine control data signals from various parametric inputs and during steady state load conditions, seeks a best V/HZ ratio to minimize battery current drawn (system losses) from a D.C. power source (32). In the preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack and a three-phase induction motor (18).

  1. Upgrade of the inverted source of polarized electrons at ELSA

    NASA Astrophysics Data System (ADS)

    Heiliger, D.; Hillert, W.; Neff, B.

    2011-05-01

    Since 2000 an inverted source of polarized electrons at the electron stretcher accelerator ELSA routinely provides a pulsed beam with a polarization degree of about 80%. One micro-second long pulses with 100 nC charge are produced by irradiating a strained-layer superlattice photocathode with laser light from a flashlamp-pumped Ti:Sa laser. A rectangular pulse shape is achieved by operating the source in space charge limitation. The proposed hadron physics program requires an intensity upgrade to 200 mA which can be achieved by enlarging the emission area or by improving the quantum efficiency (QE). The resulting changes of the beam parameters (like emittance and space charge) and of the optics of the transfer line were investigated in numerical simulations. In order to enhance the source performance a new load lock system with crystal storage and atomic hydrogen cleaning will be installed in the near future.

  2. ELECTROSTATIC MODELING OF THE JEFFERSON LABORATORY INVERTED CERAMIC GUN

    SciTech Connect

    P. Evtushenko ,F.E. Hannon, C. Hernandez-Garcia

    2010-05-01

    Jefferson Laboratory (JLab) is currently developing a new 500kV DC electron gun for future use with the FEL. The design consists of two inverted ceramics which support a central cathode electrode. This layout allows for a load-lock system to be located behind the gun chamber. The electrostatic geometry of the gun has been designed to minimize surface electric field gradients and also to provide some transverse focusing to the electron beam during transit between the cathode and anode. This paper discusses the electrode design philosophy and presents the results of electrostatic simulations. The electric field information obtained through modeling was used with particle tracking codes to predict the effects on the electron beam.

  3. A case of gastric hamartomatous inverted polyp resected endoscopically

    PubMed Central

    Dohi, Moyu; Gen, Yasuyuki; Yoshioka, Mika

    2016-01-01

    We report the case of a 55-year-old woman with a tumor in the greater curvature of the upper gastric body. The tumor was incidentally found on an upper gastrointestinal X-ray series performed during a routine medical examination. Whereas endoscopy revealed a gastric submucosal tumor (SMT), endoscopic ultrasonography demonstrated a heterogeneous tumor with small, cystic, hypoechoic spots originating from the second layer. The patient was clinically asymptomatic, with no contributory family history or abnormal laboratory data. The results of a physical examination, abdominal computed tomography, and plain chest radiography were all unremarkable. Although the endoscopic tumor type was determined to be SMT, the tumor was successfully resected by endoscopic submucosal dissection (ESD) and subsequently diagnosed as a gastric hamartomatous inverted polyp (GHIP). The findings of the present case highlight the importance of considering GHIP as a diagnosis and indicate the utility of en bloc resection of GHIP with ESD. PMID:27556064

  4. Suspended-Patch Antenna With Inverted, EM-Coupled Feed

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    An improved suspended-patch antenna has been designed to operate at a frequency of about 23 GHz with linear polarization and to be one of four identical antennas in a rectangular array. The antenna includes a parasitic patch on top of a suspended dielectric superstrate, an active patch on top of a suspended dielectric substrate, a microstrip on the bottom of the dielectric substrate, and a ground plane. The microstrip, the ground plane, the airgap between them, and the dielectric substrate together constitute a transmission line that has an impedance of 50 Ohm and is electromagnetically (EM) coupled to the active patch. The parasitic patch is, in turn, excited by the active patch. The microstrip feed is characterized as inverted because the microstrip is on the bottom of the substrate, whereas microstrips are usually placed on the tops of dielectric substrates

  5. Inverted Internal Limiting Membrane Flap For Large Traumatic Macular Holes.

    PubMed

    Abou Shousha, Mohsen Ahmed

    2016-01-01

    The aim of the study was to assess the role of inverted internal limiting membrane flap as a treatment option for large traumatic macular holes.This is a prospective noncomparative study in which 12 eyes with large traumatic macular holes (basal diameter of 1300-2800 μm) since 3 to 6 months were subjected to standard 23-gauge vitrectomy with removal of the posterior hyaloid, brilliant blue G (BBG)-assisted internal limiting membrane peeling in a circular fashion keeping it attached to the edge of the hole to create a flap. At the end of the surgery, air fluid exchange was done with inversion of the internal limiting membrane flap inside the macular hole using the soft tipped cannula and sulfur hexafluoride 20% as tamponade. The main follow-up measures are the best corrected visual acuity and the optical coherence tomography for 6 to 9 months.All the included eyes had a closed hole from the first week postoperative and along the follow-up period (6-9 months). The best corrected visual acuity improved from 20/2000 to 20/200 with a median of 20/400 preoperatively to 20/400 to 20/50 with a median of 20/100 at the end of follow-up period.Inverted internal limiting membrane flap is a good adjuvant to standard vitrectomy in the management of large traumatic macular holes that led to the 100% closure rate and improvement of best corrected visual acuity. PMID:26817894

  6. Analysis and modeling of a family of two-transistor parallel inverters

    NASA Technical Reports Server (NTRS)

    Lee, F. C. Y.; Wilson, T. G.

    1973-01-01

    A family of five static dc-to-square-wave inverters, each employing a square-loop magnetic core in conjunction with two switching transistors, is analyzed using piecewise-linear models for the nonlinear characteristics of the transistors, diodes, and saturable-core devices. Four of the inverters are analyzed in detail for the first time. These analyses show that, by proper choice of a frame of reference, each of the five quite differently appearing inverter circuits can be described by a common equivalent circuit. This equivalent circuit consists of a five-segment nonlinear resistor, a nonlinear saturable reactor, and a linear capacitor. Thus, by proper interpretation and identification of the parameters in the different circuits, the results of a detailed solution for one of the inverter circuits provide similar information and insight into the local and global behavior of each inverter in the family.

  7. Research on inverter test system of synchronous motor using modbus communication

    NASA Astrophysics Data System (ADS)

    Cao, Wenlun; Chen, Bei; He, Yuyao

    2013-03-01

    In this paper, the hardware architecture of the servo system composed by self-made inverter and permanent magnet synchronous motor is introduced as well as its measurement and control system software features. Basing on the Modbus-RTU protocols which contain the CRC data verification between IPC and the inverter, we have built a communication system. The measurement and control software of servo system are realized, which consists of self-made inverter and PMSM. Compared with the servo system which consists of Schindler's ATV31 inverter and SIMO's asynchronous motor, the results are given. The experiment parameters include harmonic content which is contained by phase current and voltage, and also the motor speed. The results show that the measurement and control system are stable and reliable. Both the harmonic content of the Inverter output and the motor speed meet the requirements.

  8. A current-source inverter fed induction motor drive system with reduced losses

    SciTech Connect

    Espinoza, J.R.; Joos, G.

    1995-12-31

    Standard low and medium induction power motor drives are based on the PWM voltage source inverter (VSI) fed from a diode rectifier. The dual topology, based on the current source inverter/rectifier structure is used in medium and high power applications. This paper addresses some of the drawbacks of this approach compared to the voltage source approach. The proposed drive features: (a) an on-line operated PWM inverter, using instantaneous output capacitor voltage control based on space vector modulation; (b) a line-synchronized PWM rectifier, with dc bus current control; (c) an additional inverter modulation index control loop, ensuring a constant inverter modulation index. The resulting advantages include: (a) ruggedness and inherent continuous regeneration capability; (b) near unity global input power factor; (c) reduced motor voltage distortion; (d) reduced dc bus inductor and switch conduction losses; (e) fast motor dynamic response; (f) elimination of motor circuit resonances. Simulated and experimental results based on a DSP implementation are given.

  9. Intracranial extension of Schneiderian inverted papilloma: a case report and literature review

    PubMed Central

    Pitak-Arnnop, Poramate; Bertolini, Julia; Dhanuthai, Kittipong; Hendricks, Jörg; Hemprich, Alexander; Pausch, Niels Christian

    2012-01-01

    Inverted papilloma is an uncommon primary nasal tumor. Despite its benign nature, this tumor represents three typical characteristics: a high propensity of recurrence, local aggressiveness and association with malignancy. Inverted papilloma can reduce the patient’s quality of life due to compromised nasal function, extension to the orbit and brain. The authors reported the unusual case of a 72-year-old male patient with inverted papilloma, which fatally extended to the intracranial temporal fossa after multiple recurrences. To the authors’ knowledge, this is the twelfth case in the literature of inverted papilla extending into the temporal fossa. The current and pertinent literature in English, French and German was reviewed, and an algorithm for managing inverted papilloma was also proposed. PMID:22737105

  10. Evaluation of Multiple Inverter Volt-VAR Control Interactions with Realistic Grid Impedances

    SciTech Connect

    Chakraborty, Sudipta; Hoke, Anderson; Lundstrom, Blake

    2015-07-03

    Integration of large numbers of distributed photovoltaic (PV) systems in electric distribution circuits often requires advanced functions (e.g. volt-VAR, frequency-Watt etc.). However, significant concerns have been raised about potential for PV inverters with such controls to interact with one another in a way that could cause grid instability. The lack of standardized inverter models makes it hard to simulate such transient interactions in software. Similarly it is very hard to test these dynamic inverter interactions in the laboratory. In this paper, unique Power Hardware-in-the-Loop (PHIL) techniques are presented to experimentally test for interactions of multiple PV inverters connected to multiple points-of-common-coupling (PCCs) with grid impedances between them. Sample test results are provided from simulation-only scenarios and PHIL testing. Though simulation results indicated possible harmful interactions between inverters' volt-VAR controllers; no such interactions were found in the limited hardware testing.

  11. Improvement on an inverted decoupling technique for a class of stable linear multivariable processes.

    PubMed

    Chen, Peiying; Zhang, Weidong

    2007-04-01

    This paper improves an inverted decoupling technique for a class of stable linear multivariable processes with multiple time delays and nonminimum-phase zeros. Two decoupling schemes are proposed based on the inverted decoupling technique. One is a developed inverted decoupling scheme. In this scheme, the decoupler is designed such that the inverted decoupling technique accommodates a wider field than the one introduced in the published literature. However, due to the stability issue, some multivariable processes still cannot be decoupled by the inverted decoupling structure. To solve this problem, another modified decoupling scheme with unity feedback structure is suggested for implementation. The Internal Model Control (IMC) theory is applied here to design PI/PID controllers for the decoupled processes. Furthermore, in the presence of multiplicative input uncertainty, low bounds of the control parameters are derived quantitatively for guaranteeing robust stability of the system. Simulations are illustrated for demonstrating the validity of the proposed control schemes. PMID:17343860

  12. Assumption or Fact? Line-to-Neutral Voltage Expression in an Unbalanced 3-Phase Circuit during Inverter Switching

    ERIC Educational Resources Information Center

    Masrur, M. A.

    2009-01-01

    This paper discusses the situation in a 3-phase motor or any other 3-phase system operating under unbalanced operating conditions caused by an open fault in an inverter switch. A dc voltage source is assumed as the input to the inverter, and under faulty conditions of the inverter switch, the actual voltage applied between the line to neutral…

  13. A Preliminary Cost Study of the Dual Mode Inverter Controller

    SciTech Connect

    McKeever, J.W.

    2005-01-28

    In 1998, the Power Electronics and Electric Machinery Research Center (PEEMRC) at the Oak Ridge National Laboratory (ORNL) started a program to investigate alternate field weakening schemes for permanent magnet (PM) motors. The adjective ''alternate'' was used because at that time, outside research emphasis was on motors with interior-mounted PMs (IPMs). The PEEMRC emphasis was placed on motors with surface-mounted PMs (SPMs) because of the relative ease of manufacturing SPM motors compared with the IPM motors. Today the PEEMRC is continuing research on SPMs while examining the IPMs that have been developed by industry. Out of this task--the goal of which was to find ways to drive PM motors that inherently have low inductance at high speeds where their back-emf exceeds the supply voltage--ORNL developed and demonstrated the dual mode inverter control (DMIC) [1,2] method of field weakening for SPM motors. The predecessor of DMIC is conventional phase advance (CPA), which was developed by UQM Technologies, Inc. [3]. Fig. 1 shows the three sets of anti-parallel thyristors in the dashed box that comprise the DMIC. If one removes the dashed box by shorting each set of anti-parallel thyristors, the configuration becomes a conventional full bridge inverter on the left driving a three phase motor on the right. CPA may be used to drive this configuration ORNL's initial analyses of CPA and DMIC were based on driving motors with trapezoidal back-emfs [4-6], obtained using double layer lapped stator windings with one slot per pole per phase. A PM motor with a sinusoidal back-emf obtained with two poles per slot per phase has been analyzed under DMIC operation as a University of Tennessee-Knoxville (UTK) doctoral dissertation [7]. In the process of this research, ORNL has completed an analysis that explains and quantifies the role of inductance in these methods of control. The Appendix includes information on the equations for the three components of phase inductance, L{sub gap

  14. Comparison of Vertical and Inverted-T Mammaplasties Using Photographic Measurements

    PubMed Central

    2013-01-01

    Background: Surgeons have long debated the relative merits of vertical and inverted-T mammaplasties. These debates have centered on surgeons’ opinions. Without measurements, this controversy is unlikely to be resolved. This study compares these common techniques using a recently published measurement system. Such a study using measurements on photographs matched for size and orientation has not been previously published. Methods: A prospective group of women undergoing primary vertical mastopexies, augmentation/mastopexies, and reductions (n = 78) was compared with a retrospective group of women treated with inverted-T mastopexies, augmentation/mastopexies, and reductions (n = 35). Consecutive patients with photographs at least 3 months after surgery and no subsequent procedures were evaluated. Results: All patient groups demonstrated a significant elevation (P < 0.001) of the breast mound. Vertical mastopexy, but not inverted-T mastopexy, increased breast projection and upper pole projection (P < 0.008). Neither vertical nor inverted-T breast reduction significantly increased breast projection. Vertical breast reduction better preserved breast projection (P < 0.017) than the inverted-T technique. Vertical reduction significantly increased upper pole projection (P < 0.008), but inverted-T reduction did not. The inverted-T breast reduction caused greater breast constriction (reduced lower pole distance) than the vertical technique. Lower pole ratios were significantly higher for inverted-T patients (P < 0.01), indicating boxier lower poles. Conclusions: Photographic measurements of relevant breast parameters favor the vertical technique over the inverted-T technique and are consistent with anatomical considerations and clinical experience. PMID:25289283

  15. Influence of doping on charge carrier collection in normal and inverted geometry polymer:fullerene solar cells

    NASA Astrophysics Data System (ADS)

    Dibb, George F. A.; Muth, Mathis-Andreas; Kirchartz, Thomas; Engmann, Sebastian; Hoppe, Harald; Gobsch, Gerhard; Thelakkat, Mukundan; Blouin, Nicolas; Tierney, Steve; Carrasco-Orozco, Miguel; Durrant, James R.; Nelson, Jenny

    2013-11-01

    While organic semiconductors used in polymer:fullerene photovoltaics are generally not intentionally doped, significant levels of unintentional doping have previously been reported in the literature. Here, we explain the differences in photocurrent collection between standard (transparent anode) and inverted (transparent cathode) low band-gap polymer:fullerene solar cells in terms of unintentional p-type doping. Using capacitance/voltage measurements, we find that the devices exhibit doping levels of order 1016 cm-3, resulting in space-charge regions ~100 nm thick at short circuit. As a result, low field regions form in devices thicker than 100 nm. Because more of the light is absorbed in the low field region in standard than in inverted architectures, the losses due to inefficient charge collection are greater in standard architectures. Using optical modelling, we show that the observed trends in photocurrent with device architecture and thickness can be explained if only charge carriers photogenerated in the depletion region contribute to the photocurrent.

  16. Baseline Serum Lactate Dehydrogenase Levels for Patients Treated With Intensity-Modulated Radiotherapy for Nasopharyngeal Carcinoma: A Predictor of Poor Prognosis and Subsequent Liver Metastasis

    SciTech Connect

    Zhou Guanqun; Tang Linglong; Mao Yanping; Chen Lei; Li Wenfei; Sun Ying; Liu Lizhi; Li Li; Lin Aihua; Ma Jun

    2012-03-01

    Purpose: To evaluate the prognostic value of baseline serum lactate dehydrogenase (LDH) levels in patients with nasopharyngeal carcinoma (NPC) treated with intensity-modulated radiotherapy (IMRT). Methods and Materials: Cases of NPC (n = 465) that involved treatment with IMRT with or without chemotherapy were retrospectively analyzed. Results: The mean ({+-}SD) and median baseline serum LDH levels for this cohort were 172.77 {+-} 2.28 and 164.00 IU/L, respectively. Levels of LDH were significantly elevated in patients with locoregionally advanced disease (p = 0.016). Elevated LDH levels were identified as a prognostic factor for rates of overall survival (OS), disease-free survival (DFS), and distant metastasis-free survival (DMFS), with p values <0.001 in the univariate analysis and p < 0.001, p = 0.004, and p = 0.003, respectively, in the multivariate analysis. Correspondingly, the prognostic impact of patient LDH levels was found to be statistically significant for rates of OS, DFS, and DMFS (p = 0.028, 0.024, and 0.020, respectively). For patients who experienced subsequent liver failure after treatment, markedly higher pretreatment serum LDH levels were detected compared with patients experiencing distant metastasis events at other sites (p = 0.032). Conclusions: Elevated baseline LDH levels are associated with clinically advanced disease and are a poor prognosticator for OS, DFS, and DMFS for NPC patients. These results suggest that elevated serum levels of LDH should be considered when evaluating treatment options.

  17. Polarization-encoded all-optical quaternary universal inverter and design of multivalued flip-flop

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay; Roy, Jitendra Nath

    2010-03-01

    Quaternary inverters are the fundamental building blocks of multivalued flip-flops (MVFFs). A novel all-optical quaternary universal inverter circuit with the help of a semiconductor optical amplifier-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization states of light. A terahertz optical asymmetric multiplexer-based gate plays an important role here. Numerical simulation results confirming the described method are given. An all-optical circuit for a MVFF (quaternary) with the help of our proposed quaternary universal inverter is also designed, and simulation results are presented.

  18. A new inverter topology using GTO commutation. [Gate Turn Off thyristor

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.

    1983-01-01

    A new N-phase, forced commutated bridge inverter topology has been developed wherein a single Gate Turn Off Thyristor (GTO) is used to commutate each of 2N main Thyristors (SCRs). Since, for most applications, the primary loss mechanism is the SCR forward drop, very high efficiencies are possible. Compared with conventional pure SCR and pure GTO inverters, cost per kW is lower - in the former case due to the large cost differential between GTOs and SCRs. Other advantages of the new inverter include high power density, low switching losses and stresses, modulation flexibility and amenability to high voltage and high frequency operation.

  19. Silicon-controlled-rectifier square-wave inverter with protection against commutation failure

    NASA Technical Reports Server (NTRS)

    Birchenough, A. G.

    1971-01-01

    The square-wave SCR inverter that was designed, built, and tested includes a circuit to turn off the inverter in case of commutation failure. The basic power stage is a complementary impulse-commutated parallel inverter consisting of only six components. The 400-watt breadboard was tested while operating at + or - 28 volts, and it had a peak efficiency of 95.5 percent at 60 hertz and 91.7 percent at 400 hertz. The voltage regulation for a fixed input was 3 percent at 60 hertz. An analysis of the operation and design information is included.

  20. Static and flyover noise measurements of an inverted profile exhaust jet

    NASA Technical Reports Server (NTRS)

    Burcham, F. W., Jr.; Lasagna, P. L.; Kurtenbach, F. J.

    1977-01-01

    Tests using a TF30 mixed flow afterburning turbofan engine in an F-111 airplane were conducted to study the noise characteristics of an inverted velocity profile jet. Full-authority digital engine control allowed the inverted profile jet to be compared to a uniform jet of equal thrust statically and in flight. An exhaust velocity survey showed that the ratio of the outer to inner stream velocities was 1.37; therefore, only small noise reductions were expected. At static conditions, the inverted profile jet was approximately 3 decibels quieter than the uniform jet at peak noise angles. During a flyover it was approximately 1 decibel quieter.

  1. High fill factor and thermal stability of bilayer organic photovoltaic cells with an inverted structure

    NASA Astrophysics Data System (ADS)

    Wang, Zhongqiang; Hong, Ziruo; Zhuang, Taojun; Chen, Guo; Sasabe, Hisahiro; Yokoyama, Daisuke; Kido, Junji

    2015-02-01

    In this study, we fabricated planar heterojunction photovoltaic cells with inverted device structures based on tetraphenyldibenzoperiflanthene and fullerene-70 (C70). With proper designs of device architecture and selection of electrode buffers, a high fill factor and power conversion efficiency were obtained due to large shunt resistance (Rsh) and efficient carrier collection. Optical simulation reveals that field-dependent recombination is depressed in the inverted structure cells because of less light absorption in short wavelength range, resulting in high fill factor. More importantly, high thermal stability of inverted structure cells was demonstrated via utilizing stable electrode buffers.

  2. Four new cases of inverted terminal duplication: A modified hypothesis of mechanism of origin

    SciTech Connect

    Hoo, J.J.; Chao, M.; Szego, K.

    1995-09-25

    We present 4 recently diagnosed cases of inverted tandem duplication with involvement of the respective terminal band. Based on these 4 cases and review of the literature, the term {open_quotes}inverted terminal duplication{close_quotes} is proposed to designate specifically the type of inverted tandem duplication which involves the terminal band. A modification of the previous hypothesis of mechanism of origin is advanced. It is speculated further that a telomeric deletion of a meiotic chromosome followed by a U-type reunion of the chromatids, considered to be the first steps of the proposed mechanism of origin, may not be a rare gonadal event. 12 refs., 5 figs.

  3. Intra-abdominal inverted umblical cord in gastroschisis: a unique ultrasound finding.

    PubMed

    Koc, Gonca; Courtier, Jesse L; Kim, Jane S; Miniati, Douglas N; MacKenzie, John D

    2014-01-01

    A relatively new surgical technique allows for sutureless closure of a gastroschisis defect. Immediately after birth, a long umbilical cord stump is temporarily inverted into the abdominal cavity and later retracted and used to close the abdominal wall defect. Knowledge of this entity is important since the inverted umbilical cord simulates an intra-abdominal mass on cross-sectional imaging. While this procedure is well described in the surgical literature, the imaging features of inverted umbilical cord have yet to be reported. The case presented here highlights the sonographic imaging findings of the umbilical cord during the intestinal decompression phase of sutureless repair of gastroschisis. PMID:23907187

  4. Prognostic significance of pretreated serum lactate dehydrogenase level in nasopharyngeal carcinoma among Chinese population

    PubMed Central

    Zhang, Mingwei; Wei, Shushan; Su, Li; Lv, Wenlong; Hong, Jinsheng

    2016-01-01

    Abstract Background: A large number of studies have investigated the prognostic value of pretreated lactate dehydrogenase (LDH) level in nasopharyngeal carcinoma (NPC) patients while the role of it was inconsistent and inconclusive. Hence, the aim of the current study was to conduct a meta-analysis of all published studies to quantify the prognostic impact of pretreated serum LDH in NPC for Chinese population. Objectives: The aim of the current study was to conduct a meta-analysis of all published studies to quantify the prognostic impact of pretreated serum lactate dehydrogenase (LDH) in nasopharyngeal carcinoma (NPC) for Chinese population. Methods: The PubMed, Medline, Embase, and Web of Science databases were searched for studies that assessed survival outcome and LDH in NPC. Overall survival (OS) was the primary survival outcome. Distant metastasis-free survival (DMFS) and disease-free survival (DFS) were secondary outcomes. The pooled hazard ratios (HRs), associated with 95% confidence intervals (95% CIs), were combined to calculate overall effects. The Cochran Q and I2 statistics were used to assess heterogeneity. When apparent heterogeneity was observed, sensitivity and meta-regression analyses were performed to explore its origin. Results: Sixteen studies, which included 14,803 patients, were enrolled in the current meta-analysis to yield statistics. Overall, the pooled HR for OS in 11 eligible studies with high LDH level was 1.79 (95% CI = 1.47–2.12), and the pooled HR for DMFS in 9 eligible studies with high LDH level was 1.85 (95% CI = 1.48–2.22). Meanwhile, the pooled HR for DFS in 5 eligible studies with high LDH level was 1.63 (95% CI = 1.34–1.91). Egger test and funnel plots revealed that the publication bias in the current meta-analysis was insignificant. Conclusions: The present meta-analysis demonstrated that high pretreated LDH level is significantly associated with poorer OS, DMFS, and DFS, suggesting that pretreated LDH could

  5. Hexaazatrinaphthylene Derivatives: Efficient Electron-Transporting Materials with Tunable Energy Levels for Inverted Perovskite Solar Cells.

    PubMed

    Zhao, Dongbing; Zhu, Zonglong; Kuo, Ming-Yu; Chueh, Chu-Chen; Jen, Alex K-Y

    2016-07-25

    Hexaazatrinaphthylene (HATNA) derivatives have been successfully shown to function as efficient electron-transporting materials (ETMs) for perovskite solar cells (PVSCs). The cells demonstrate a superior power conversion efficiency (PCE) of 17.6 % with negligible hysteresis. This study provides one of the first nonfullerene small-molecule-based ETMs for high-performance p-i-n PVSCs. PMID:27273656

  6. Radiation dependence of inverter propagation delay from timing sampler measurements

    NASA Technical Reports Server (NTRS)

    Buehler, M. G.; Blaes, B. R.; Lin, Y.-S.

    1989-01-01

    A timing sampler consisting of 14 four-stage inverter-pair chains with different load capacitances was fabricated in 1.6-micron n-well CMOS and irradiated with cobalt-60 at 10 rad(Si)/s. For this CMOS process the measured results indicate that the rising delay increases by about 2.2 ns/Mrad(Si) and the falling delay increase is very small, i.e., less than 300 ps/Mrad(Si). The amount of radiation-induced delay depends on the size of the load capacitance. The maximum value observed for this effect was 5.65 ns/pF-Mrad(Si). Using a sensitivity analysis, the sensitivity of the rising delay to radiation can be explained by a simple timing model and the radiation sensitivity of dc MOSFET parameters. This same approach could not explain the insensitivity of the falling delay to radiation. This may be due to a failure of the timing model and/or trapping effects.

  7. Efficiency optimal control for AC drives with PWM inverters

    SciTech Connect

    Zach, F.C.; Ertl, H.

    1985-07-01

    For electrical drives using pulsewidth modulation (PWM) inverters and ac motors, methods for efficiency optimal control (EOC) have been developed. They are based on the most complete motor models, including such features as rotor skin effect. Furthermore, new solutions for selected harmonic elimination (SHE) are given. These new solutions come close to EOC. Also, it has been found that EOC solutions (although basically load-dependent as opposed to SHE) do not vary much with the motor used or the motor model applied. Even using a simple R-L series circuit as motor model does not change the solutions much. It is found that using the solutions gained from such a simple model is not more than two points off the real optimum based on a very complete motor model. (For this definition, the absolute harmonic loss minimum is given as zero points, the overall maximum as 100 points with a linear scale in between.) Therefore, one can use one EOC solution for all motors with sufficient accuracy, or, as second best solution, the new form of SHE. Therefore, the EOC solution can be judged load-independent. The implementation by microprocessor-based systems is as easy for other PWM methods. EOC for three and five switching angles per quarter period is discussed, as well as the new solutions for SHE for up to nine angles.

  8. Magnetic materials selection for static inverter and converter transformers

    NASA Technical Reports Server (NTRS)

    Mclyman, W. T.

    1973-01-01

    A program to study magnetic materials is described for use in spacecraft transformers used in static inverters, converters, and transformer-rectifier supplies. Different magnetic alloys best suited for high-frequency and high-efficiency applications were comparatively investigated together with an investigation of each alloy's inherent characteristics. The materials evaluated were the magnetic alloys: (1) 50% Ni, 50% Fe; (2) 79% Ni, 17% Fe, 4% Mo; (3) 48% Ni, 52% Fe; (4) 78% Ni, 17% Fe, 5% Mo; and (5) 3% Si, 97% Fe. Investigations led to the design of a transformer with a very low residual flux. Tests were performed to determine the dc and ac magnetic properties at 2400 Hz using square-wave excitation. These tests were performed on uncut cores, which were then cut for comparison of the gapped and ungapped magnetic properties. When the data of many transformers in many configurations were compiled the optimum transformer was found to be that with the lowest residual flux and a small amount of air gap in the magnetic material. The data obtained from these tests are described, and the potential uses for the materials are discussed.

  9. Math expression retrieval using an inverted index over symbol pairs

    NASA Astrophysics Data System (ADS)

    Stalnaker, David; Zanibbi, Richard

    2015-01-01

    We introduce a new method for indexing and retrieving mathematical expressions, and a new protocol for evaluating math formula retrieval systems. The Tangent search engine uses an inverted index over pairs of symbols in math expressions. Each key in the index is a pair of symbols along with their relative distance and vertical displacement within an expression. Matched expressions are ranked by the harmonic mean of the percentage of symbol pairs matched in the query, and the percentage of symbol pairs matched in the candidate expression. We have found that our method is fast enough for use in real time and finds partial matches well, such as when subexpressions are re-arranged (e.g. expressions moved from the left to the right of an equals sign) or when individual symbols (e.g. variables) differ from a query expression. In an experiment using expressions from English Wikipedia, student and faculty participants (N=20) found expressions returned by Tangent significantly more similar than those from a text-based retrieval system (Lucene) adapted for mathematical expressions. Participants provided similarity ratings using a 5-point Likert scale, evaluating expressions from both algorithms one-at-a-time in a randomized order to avoid bias from the position of hits in search result lists. For the Lucene-based system, precision for the top 1 and 10 hits averaged 60% and 39% across queries respectively, while for Tangent mean precision at 1 and 10 were 99% and 60%. A demonstration and source code are publicly available.

  10. Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Hartwig, Jason W.; Rame, Enrique; McQuillen, John B.

    2014-01-01

    NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMD's), such as screen channel capillary liquid acquisition devices (LAD's), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity of these results to flow rate and tank internal pressure.

  11. Inverted Outflow Ground Testing of Cryogenic Propellant Liquid Acquisition Devices

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Hartwig, Jason W.; Rame, Enrique; McQuillen, John B.

    2014-01-01

    NASA is currently developing propulsion system concepts for human exploration. These propulsion concepts will require the vapor free acquisition and delivery of the cryogenic propellants stored in the propulsion tanks during periods of microgravity to the exploration vehicles engines. Propellant management devices (PMDs), such as screen channel capillary liquid acquisition devices (LADs), vanes and sponges have been used for earth storable propellants in the Space Shuttle Orbiter and other spacecraft propulsion systems, but only very limited propellant management capability currently exists for cryogenic propellants. NASA is developing PMD technology as a part of their cryogenic fluid management (CFM) project. System concept studies have looked at the key factors that dictate the size and shape of PMD devices and established screen channel LADs as an important component of PMD design. Modeling validated by normal gravity experiments is examining the behavior of the flow in the LAD channel assemblies (as opposed to only prior testing of screen samples) at the flow rates representative of actual engine service (similar in size to current launch vehicle upper stage engines). Recently testing of rectangular LAD channels has included inverted outflow in liquid oxygen and liquid hydrogen. This paper will report the results of liquid oxygen testing compare and contrast them with the recently published hydrogen results; and identify the sensitivity these results to flow rate and tank internal pressure.

  12. ``Spin inverter'' as building block of All Spin Logic devices

    NASA Astrophysics Data System (ADS)

    Sarkar, Angik; Srinivasan, Srikant; Datta, Supriyo

    2012-02-01

    All-spin logic (ASL) represents a new approach to information processing where the roles of charges and capacitors in charge based transistors are played by spins and magnets, without the need for repeated spin-charge conversion. In our past work, we have presented numerical simulations based on a coupled spin transport and Landau Lifshitz Gilbert model showing that ring oscillators and logic circuits with intrinsic directionality [IEEE Trans. Magn. 47,10, 4026, 2011; Proc. IEDM, 2011)] can be implemented by manipulation of spins in magnetic nanostructures. The aim of this talk is (1) to identify a basic ASL unit that can be interconnected to build up spin circuits analogous to the way transistors are interconnected to build conventional circuits and (2) to present a compact model for this basic unit that can be used to design and analyze large scale spin circuits. We will show that this basic ASL unit is a one-magnet ``spin inverter'' with gain that can be cascaded to accomplish a spin circuit implementation of almost any logic functionality

  13. Inverted papillomas and benign nonneoplastic lesions of the nasal cavity

    PubMed Central

    Casiano, Roy R.

    2012-01-01

    Background: Benign lesions of the nasal cavity represent a diverse group of pathologies. Furthermore, each of these disorders may present differently in any given patient as pain and discomfort, epistaxis, headaches, vision changes, or nasal obstruction. Although these nasal masses are benign, many of them have a significant capacity for local tissue destruction and symptomatology secondary to this destruction. Advances in office-based endoscopic nasendoscopy have equipped the otolaryngologist with a safe, inexpensive, and rapid means of directly visualizing lesions within the nasal cavity and the initiation of appropriate treatment. Methods: The purpose of this study is to review the diagnosis, management, and controversies of many of the most common benign lesions of the nasal cavity encountered by the primary care physician or otolaryngologist. Results: This includes discussion of inverted papilloma (IP), juvenile angiofibroma, squamous papilloma, pyogenic granuloma, hereditary hemorrhagic telangiectasia, schwannoma, benign fibro-osseous lesions, and other benign lesions of the nasal cavity, with particular emphasis on IP and juvenile angiofibroma. Conclusion: A diverse array of benign lesions occur within the nasal cavity and paranasal cavities. Despite their inability to metastasize, many of these lesions have significant capability for local tissue destruction and recurrence. PMID:22487294

  14. Substrate and electrode potential affect electrotrophic activity of inverted bioanodes.

    PubMed

    Hartline, Rosanna M; Call, Douglas F

    2016-08-01

    Electricity-consuming microbial communities can serve as biocathodic catalysts in microbial electrochemical technologies. Initiating their functionality, however, remains a challenge. One promising approach is the polarity inversion of bioanodes. The objective of this study was to examine the impact of bioanode substrate and electrode potentials on inverted electrotrophic activity. Bioanodes derived from domestic wastewater were operated at -0.15V or +0.15V (vs. standard hydrogen electrode) with either acetate or formate as the sole carbon source. After this enrichment phase, cathodic linear sweep voltammetry and polarization revealed that formate-enriched cultures consumed almost 20 times the current (-3.0±0.78mA; -100±26A/m(3)) than those established with acetate (-0.16±0.09mA; -5.2±2.9A/m(3)). The enrichment electrode potential had an appreciable impact for formate, but not acetate, adapted cultures, with the +0.15V enrichment generating twice the cathodic current of the -0.15V enrichment. The total charge consumed during cathodic polarization was comparable to the charge released during subsequent anodic polarization for the formate-adapted cultures, suggesting that these communities accumulated charge or generated reduced products that could be rapidly oxidized. These findings imply that it may be possible to optimize electrotrophic activity through specific bioanodic enrichment procedures. PMID:26946157

  15. InVERT molding for scalable control of tissue microarchitecture

    PubMed Central

    Stevens, KR; Ungrin, MD; Schwartz, RE; Ng, S; Carvalho, B; Christine, KS; Chaturvedi, RR; Li, CY; Zandstra, PW; Chen, CS; Bhatia, SN

    2013-01-01

    Complex tissues contain multiple cell types that are hierarchically organized within morphologically and functionally distinct compartments. Construction of engineered tissues with optimized tissue architecture has been limited by tissue fabrication techniques, which do not enable versatile microscale organization of multiple cell types in tissues of size adequate for physiologic studies and tissue therapies. Here we present an ‘Intaglio-Void/Embed-Relief Topographic (InVERT) molding’ method for microscale organization of many cell types, including induced pluripotent stem cell (iPS)-derived progeny, within a variety of synthetic and natural extracellular matrices and across tissues of sizes appropriate for in vitro, pre-clinical, and clinical studies. We demonstrate that compartmental placement of non-parenchymal cells relative to primary or iPS-derived hepatocytes, compartment microstructure, and cellular composition modulate hepatic functions. Configurations found to sustain physiologic function in vitro also result in survival and function in mice for at least four weeks, demonstrating the importance of architectural optimization prior to implantation. PMID:23673632

  16. Interfacial thermal degradation in inverted organic solar cells

    SciTech Connect

    Greenbank, William; Hirsch, Lionel; Wantz, Guillaume; Chambon, Sylvain

    2015-12-28

    The efficiency of organic photovoltaic (OPV) solar cells is constantly improving; however, the lifetime of the devices still requires significant improvement if the potential of OPV is to be realised. In this study, several series of inverted OPV were fabricated and thermally aged in the dark in an inert atmosphere. It was demonstrated that all of the devices undergo short circuit current-driven degradation, which is assigned to morphology changes in the active layer. In addition, a previously unreported, open circuit voltage-driven degradation mechanism was observed that is highly material specific and interfacial in origin. This mechanism was specifically observed in devices containing MoO{sub 3} and silver as hole transporting layers and electrode materials, respectively. Devices with this combination were among the worst performing devices with respect to thermal ageing. The physical origins of this mechanism were explored by Rutherford backscattering spectrometry and atomic force microscopy and an increase in roughness with thermal ageing was observed that may be partially responsible for the ageing mechanism.

  17. Development and Characterization of Inverted Helicon Plasma Sources

    NASA Astrophysics Data System (ADS)

    Masters, Benjamin; Ruzic, David

    2007-11-01

    Helicon plasmas are useful as hot, dense sources requiring low magnetic fields. Since Boswell's^1 use of helicon waves in low pressure gas, research has strived to determine the wave-plasma coupling mechanism. Trivelpiece-Gould (TG) modes^2 remain a strong candidate. An inverted helicon plasma source uses a Nagoya Type III dielectric-covered helicon antenna, placed within a vacuum chamber. The antenna is 8.2 cm long, 2.2 cm in radius, using an frequency of 13.56 MHz. Basic dispersion relation theory is developed as an extension of existing helicon theory which includes TG modes and annular helicons^3. With this arrangement, diagnostic measurements are made inside and outside the antenna volume. To characterize the plasma, an RF-compensated Langmuir probe measures ne and Te, and 3 B-dot probes measure the field shape of the R, Theta and Z components about the antenna region in the R and Z directions. Typical ne and Te in an Ar plasma were found to be 3x10^18/m^3 and 3 eV. The goal of this work is to find another configuration to determine the method of efficient plasma heating. [1] R.W. Boswell, Phys. Lett. 33A, 457 (1970) [2] A.W. Trivelpiece and R.W. Gould, Jour. App. Phys. 30 (11) (1959) [3] M. Yano and M.L.R. Walker, Phys. of Plasmas. 13 (063501) (2006)

  18. Characterization of an Inverted Geometry Helicon Plasma Source

    NASA Astrophysics Data System (ADS)

    Masters, Benjamin; Ruzic, David

    2006-10-01

    Helicon plasmas are useful as hot, dense sources requiring low magnetic fields. Since Boswell's^1 use of helicon waves in low pressure gas, no single theory fully explains the wave-plasma coupling mechanism. However, Trivelpiece-Gould modes^2 remain a strong candidate. An inverted geometry helicon plasma source is further explored, using a dielectric-covered helicon antenna, placed within a vacuum chamber, in contrast to conventional antennas that surround a dielectric cylinder. A Nagoya Type III antenna is used, other antennas are equally feasible. Many industrial advantages of such a system exist; namely, more efficient electromagnets, as well as producing a plasma with a larger radius than the antenna. With this arrangement, diagnostic measurements can be made arbitrarily close to the antenna. To characterize the plasma, an RF-compensated Langmuir probe measures electron temperature and density, while a B-dot probe measures the field shape inside and outside of the antenna region. In addition, optical emission spectroscopy observes changes in plasma intensity for mode jumps, and measures line ratios. 1. R.W. Boswell, Phys. Lett. 33A, 457 (1970) 2. A.W. Trivelpiece and R.W. Gould, Jour. App. Phys. 30 (11) (1959)

  19. An inverted continental Moho and serpentinization of the forearc mantle.

    PubMed

    Bostock, M G; Hyndman, R D; Rondenay, S; Peacock, S M

    2002-05-30

    Volatiles that are transported by subducting lithospheric plates to depths greater than 100 km are thought to induce partial melting in the overlying mantle wedge, resulting in arc magmatism and the addition of significant quantities of material to the overlying lithosphere. Asthenospheric flow and upwelling within the wedge produce increased lithospheric temperatures in this back-arc region, but the forearc mantle (in the corner of the wedge) is thought to be significantly cooler. Here we explore the structure of the mantle wedge in the southern Cascadia subduction zone using scattered teleseismic waves recorded on a dense portable array of broadband seismometers. We find very low shear-wave velocities in the cold forearc mantle indicated by the exceptional occurrence of an 'inverted' continental Moho, which reverts to normal polarity seaward of the Cascade arc. This observation provides compelling evidence for a highly hydrated and serpentinized forearc region, consistent with thermal and petrological models of the forearc mantle wedge. This serpentinized material is thought to have low strength and may therefore control the down-dip rupture limit of great thrust earthquakes, as well as the nature of large-scale flow in the mantle wedge. PMID:12037564

  20. Inverted Break-up Behaviour in Continuous Inkjet (CIJ) Printing

    NASA Astrophysics Data System (ADS)

    McIlroy, Claire; Harlen, Oliver; Morrison, Neil

    2014-11-01

    Although droplet creation during continuous jetting of Newtonian fluids has been widely studied, unsolved problems surrounding the break-up dynamics remain. Jetting through a nozzle creates a stream of liquid that is rendered unstable by surface tension. This instability creates a succession of main drops connected by thin filaments, with drop separation determined by the fastest growing wavelength. In order to control break-up and increase printing speeds, continuous inkjet (CIJ) printing exploits the effects of finite amplitude modulations in the jet velocity profile giving conditions where jet stability deviates from the usual Rayleigh behaviour. To explore these non-linear effects, we have developed a one-dimensional jetting model. In particular, we identify a modulation range for which pinching occurs upstream of the connecting filament, rather than downstream - a phenomenon we call ``inverted'' break-up. Furthermore, this behaviour can be controlled by the addition of harmonics to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry. EPSRC Innovation in Industrial Technology.