Blast transformation and fibrotic progression in polycythemia vera and essential thrombocythemia: a literature review of incidence and risk factors

PubMed Central

Cerquozzi, S; Tefferi, A

2015-01-01

Polycythemia vera (PV) and essential thrombocythemia (ET) constitute two of the three BCR-ABL1-negative myeloproliferative neoplasms and are characterized by relatively long median survivals (approximately 14 and 20 years, respectively). Potentially fatal disease complications in PV and ET include disease transformation into myelofibrosis (MF) or acute myeloid leukemia (AML). The range of reported frequencies for post-PV MF were 4.9–6% at 10 years and 6–14% at 15 years and for post-ET MF were 0.8–4.9% at 10 years and 4–11% at 15 years. The corresponding figures for post-PV AML were 2.3–14.4% at 10 years and 5.5–18.7% at 15 years and for post-ET AML were 0.7–3% at 10 years and 2.1–5.3% at 15 years. Risk factors cited for post-PV MF include advanced age, leukocytosis, reticulin fibrosis, splenomegaly and JAK2V617F allele burden and for post-ET MF include advanced age, leukocytosis, anemia, reticulin fibrosis, absence of JAK2V617F, use of anagrelide and presence of ASXL1 mutation. Risk factors for post-PV AML include advanced age, leukocytosis, reticulin fibrosis, splenomegaly, abnormal karyotype, TP53 or RUNX1 mutations as well as use of pipobroman, radiophosphorus (P32) and busulfan and for post-ET AML include advanced age, leukocytosis, anemia, extreme thrombocytosis, thrombosis, reticulin fibrosis, TP53 or RUNX1 mutations. It is important to note that some of the aforementioned incidence figures and risk factor determinations are probably inaccurate and at times conflicting because of the retrospective nature of studies and the inadvertent labeling, in some studies, of patients with prefibrotic primary MF or ‘masked' PV, as ET. Ultimately, transformation of MPN leads to poor outcomes and management remains challenging. Further understanding of the molecular events leading to disease transformation is being investigated. PMID:26565403

Experimental grid connected PV system power analysis

NASA Astrophysics Data System (ADS)

Semaoui, Smail; Abdeladim, Kamel; Arab, Amar Hadj; Boulahchich, Saliha; Amrouche, Said Ould; Yassaa, Noureddine

2018-05-01

Almost 80 % of Algerian territory is appropriate for the exploitation of solar energy. The Algerian energetic strategy provides a substantial injection of PV electricity to the national grid. Currently, about 344 MWp of PV arrays which corresponds approximately to 2,34 km2 of module surfaces, are connected on electricity grid over the national territory. The Algerian Northern regions are characterized by strong pollution and high humidity. These phenomena affect the energetic productivity of PV generator. The objective of our study is to analyze experimental grid connected PV system power in coastal locations. Hence, experiments have been conducted on three identical PV systems to determine the electrical performances. Transformer-less inverters are the most attractive for the ground-based photovoltaic (PV) system due to their efficiencies, reduced cost and weight. Besides, the absence of the galvanic isolation generates problems of capacitive leakage current on the AC side and the degradation of the insulation resistance on the DC side of the inverter. In this work, experimental study of the behavior of single-phase inverters without transformers is presented. The main objective of this work is to study the degradation of the insulation resistance at the input of the inverter, and the capacitive leakage current at the output of the inverter. This study was achieved at the CDER on a rainy day of 15/03/2017, on the first PV plant connected to the low voltage network in Algeria. This investigation can help forecasting the PV array energetic production by taking into account natural conditions.

Costs of solar and wind power variability for reducing CO2 emissions.

PubMed

Lueken, Colleen; Cohen, Gilbert E; Apt, Jay

2012-09-04

We compare the power output from a year of electricity generation data from one solar thermal plant, two solar photovoltaic (PV) arrays, and twenty Electric Reliability Council of Texas (ERCOT) wind farms. The analysis shows that solar PV electricity generation is approximately one hundred times more variable at frequencies on the order of 10(-3) Hz than solar thermal electricity generation, and the variability of wind generation lies between that of solar PV and solar thermal. We calculate the cost of variability of the different solar power sources and wind by using the costs of ancillary services and the energy required to compensate for its variability and intermittency, and the cost of variability per unit of displaced CO(2) emissions. We show the costs of variability are highly dependent on both technology type and capacity factor. California emissions data were used to calculate the cost of variability per unit of displaced CO(2) emissions. Variability cost is greatest for solar PV generation at $8-11 per MWh. The cost of variability for solar thermal generation is $5 per MWh, while that of wind generation in ERCOT was found to be on average $4 per MWh. Variability adds ~$15/tonne CO(2) to the cost of abatement for solar thermal power, $25 for wind, and $33-$40 for PV.

NREL Smart Grid Projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hambrick, J.

2012-01-01

Although implementing Smart Grid projects at the distribution level provides many advantages and opportunities for advanced operation and control, a number of significant challenges must be overcome to maintain the high level of safety and reliability that the modern grid must provide. For example, while distributed generation (DG) promises to provide opportunities to increase reliability and efficiency and may provide grid support services such as volt/var control, the presence of DG can impact distribution operation and protection schemes. Additionally, the intermittent nature of many DG energy sources such as photovoltaics (PV) can present a number of challenges to voltage regulation,more » etc. This presentation provides an overview a number of Smart Grid projects being performed by the National Renewable Energy Laboratory (NREL) along with utility, industry, and academic partners. These projects include modeling and analysis of high penetration PV scenarios (with and without energy storage), development and testing of interconnection and microgrid equipment, as well as the development and implementation of advanced instrumentation and data acquisition used to analyze the impacts of intermittent renewable resources. Additionally, standards development associated with DG interconnection and analysis as well as Smart Grid interoperability will be discussed.« less

Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro

PubMed Central

Leuchs, Barbara; Frank-Stöhr, Monika; Schlehofer, Jörg R.; Rommelaere, Jean; Lacroix, Jeannine

2017-01-01

Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo. PMID:29039746

Preclinical Testing of an Oncolytic Parvovirus: Standard Protoparvovirus H-1PV Efficiently Induces Osteosarcoma Cell Lysis In Vitro.

PubMed

Geiss, Carsten; Kis, Zoltán; Leuchs, Barbara; Frank-Stöhr, Monika; Schlehofer, Jörg R; Rommelaere, Jean; Dinsart, Christiane; Lacroix, Jeannine

2017-10-17

Osteosarcoma is the most frequent malignant disease of the bone. On the basis of early clinical experience in the 1960s with H-1 protoparvovirus (H-1PV) in osteosarcoma patients, this effective oncolytic virus was selected for systematic preclinical testing on various osteosarcoma cell cultures. A panel of five human osteosarcoma cell lines (CAL 72, H-OS, MG-63, SaOS-2, U-2OS) was tested. Virus oncoselectivity was confirmed by infecting non-malignant human neonatal fibroblasts and osteoblasts used as culture models of non-transformed mesenchymal cells. H-1PV was found to enter osteosarcoma cells and to induce viral DNA replication, transcription of viral genes, and translation to viral proteins. After H-1PV infection, release of infectious viral particles from osteosarcoma cells into the supernatant indicated successful viral assembly and egress. Crystal violet staining revealed progressive cytomorphological changes in all osteosarcoma cell lines. Infection of osteosarcoma cell lines with the standard H-1PV caused an arrest of the cell cycle in the G2 phase, and these lines had a limited capacity for standard H-1PV virus replication. The cytotoxicity of wild-type H-1PV virus towards osteosarcoma cells was compared in vitro with that of two variants, Del H-1PV and DM H-1PV, previously described as fitness variants displaying higher infectivity and spreading in human transformed cell lines of different origins. Surprisingly, wild-type H-1PV displayed the strongest cytostatic and cytotoxic effects in this analysis and thus seems the most promising for the next preclinical validation steps in vivo.

Protoplast isolation, transient transformation of leaf mesophyll protoplasts and improved Agrobacterium-mediated leaf disc infiltration of Phaseolus vulgaris: tools for rapid gene expression analysis.

PubMed

Nanjareddy, Kalpana; Arthikala, Manoj-Kumar; Blanco, Lourdes; Arellano, Elizabeth S; Lara, Miguel

2016-06-24

Phaseolus vulgaris is one of the most extensively studied model legumes in the world. The P. vulgaris genome sequence is available; therefore, the need for an efficient and rapid transformation system is more imperative than ever. The functional characterization of P. vulgaris genes is impeded chiefly due to the non-amenable nature of Phaseolus sp. to stable genetic transformation. Transient transformation systems are convenient and versatile alternatives for rapid gene functional characterization studies. Hence, the present work focuses on standardizing methodologies for protoplast isolation from multiple tissues and transient transformation protocols for rapid gene expression analysis in the recalcitrant grain legume P. vulgaris. Herein, we provide methodologies for the high-throughput isolation of leaf mesophyll-, flower petal-, hypocotyl-, root- and nodule-derived protoplasts from P. vulgaris. The highly efficient polyethylene glycol-mannitol magnesium (PEG-MMG)-mediated transformation of leaf mesophyll protoplasts was optimized using a GUS reporter gene. We used the P. vulgaris SNF1-related protein kinase 1 (PvSnRK1) gene as proof of concept to demonstrate rapid gene functional analysis. An RT-qPCR analysis of protoplasts that had been transformed with PvSnRK1-RNAi and PvSnRK1-OE vectors showed the significant downregulation and ectopic constitutive expression (overexpression), respectively, of the PvSnRK1 transcript. We also demonstrated an improved transient transformation approach, sonication-assisted Agrobacterium-mediated transformation (SAAT), for the leaf disc infiltration of P. vulgaris. Interestingly, this method resulted in a 90 % transformation efficiency and transformed 60-85 % of the cells in a given area of the leaf surface. The constitutive expression of YFP further confirmed the amenability of the system to gene functional characterization studies. We present simple and efficient methodologies for protoplast isolation from multiple P. vulgaris tissues. We also provide a high-efficiency and amenable method for leaf mesophyll transformation for rapid gene functional characterization studies. Furthermore, a modified SAAT leaf disc infiltration approach aids in validating genes and their functions. Together, these methods help to rapidly unravel novel gene functions and are promising tools for P. vulgaris research.

A Modular Multilevel Converter with Power Mismatch Control for Grid-Connected Photovoltaic Systems

DOE PAGES

Duman, Turgay; Marti, Shilpa; Moonem, M. A.; ...

2017-05-17

A modular multilevel power converter configuration for grid connected photovoltaic (PV) systems is proposed. The converter configuration replaces the conventional bulky line frequency transformer with several high frequency transformers, potentially reducing the balance of systems cost of PV systems. The front-end converter for each port is a neutral-point diode clamped (NPC) multi-level dc-dc dual-active bridge (ML-DAB) which allows maximum power point tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is a NPC inverter.more » N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e., 13.8 kV). The cascaded NPC (CNPC) inverters have the inherent advantage of using lower rated devices, smaller filters and low total harmonic distortion required for PV grid interconnection. The proposed converter system is modular, scalable, and serviceable with zero downtime with lower foot print and lower overall cost. A novel voltage balance control at each module based on power mismatch among N-ports, have been presented and verified in simulation. Analysis and simulation results are presented for the N-port converter. The converter performance has also been verified on a hardware prototype.« less

A Modular Multilevel Converter with Power Mismatch Control for Grid-Connected Photovoltaic Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duman, Turgay; Marti, Shilpa; Moonem, M. A.

A modular multilevel power converter configuration for grid connected photovoltaic (PV) systems is proposed. The converter configuration replaces the conventional bulky line frequency transformer with several high frequency transformers, potentially reducing the balance of systems cost of PV systems. The front-end converter for each port is a neutral-point diode clamped (NPC) multi-level dc-dc dual-active bridge (ML-DAB) which allows maximum power point tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is a NPC inverter.more » N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e., 13.8 kV). The cascaded NPC (CNPC) inverters have the inherent advantage of using lower rated devices, smaller filters and low total harmonic distortion required for PV grid interconnection. The proposed converter system is modular, scalable, and serviceable with zero downtime with lower foot print and lower overall cost. A novel voltage balance control at each module based on power mismatch among N-ports, have been presented and verified in simulation. Analysis and simulation results are presented for the N-port converter. The converter performance has also been verified on a hardware prototype.« less

Hairy root transgene expression analysis of a secretory peroxidase (PvPOX1) from common bean infected by Fusarium wilt.

PubMed

Xue, Renfeng; Wu, Xingbo; Wang, Yingjie; Zhuang, Yan; Chen, Jian; Wu, Jing; Ge, Weide; Wang, Lanfen; Wang, Shumin; Blair, Matthew W

2017-07-01

Plant peroxidases (POXs) are one of the most important redox enzymes in the defense responses. However, the large number of different plant POX genes makes it necessary to carefully confirm the function of each paralogous POX gene in specific tissues and disease interactions. Fusarium wilt is a devastating disease of common bean caused by Fusarium oxysporum f. sp. phaseoli. In this study, we evaluated a peroxidase gene, PvPOX1, from a resistant common bean genotype, CAAS260205 and provided direct evidence for PvPOX1's role in resistance by transforming the resistant allele into a susceptible common bean genotype, BRB130, via hairy root transformation using Agrobacterium rhizogenes. Analysis of PvPOX1 gene over-expressing hairy roots showed it increased resistance to Fusarium wilt both in the roots and the rest of transgenic plants. Meanwhile, the PvPOX1 expressive level, the peroxidase activity and hydrogen peroxide (H 2 O 2 ) accumulation were also enhanced in the interaction. The result showed that the PvPOX1 gene played an essential role in Fusarium wilt resistance through the occurrence of reactive oxygen species (ROS) induced hypersensitive response. Therefore, PvPOX1 expression was proven to be a valuable gene for further analysis which can strengthen host defense response against Fusarium wilt through a ROS activated resistance mechanism. Copyright © 2017 Elsevier B.V. All rights reserved.

Radiative Effects of Atmospheric Aerosols and Impacts on Solar Photovoltaic Electricity Generation

NASA Astrophysics Data System (ADS)

Lund, Cory Christopher

Atmospheric aerosols, by scattering and absorbing radiation, perturbs the Earth's energy balance and reduces the amount of insolation reaching the surface. This dissertation first studies the radiative effects of aerosols by analyzing the internal mixing of various aerosol species. It then examines the aerosol impact on solar PV efficiency and the resulting influence on power systems, including both atmospheric aerosols and deposition of particulate matter (PM) on PV surfaces,. Chapter 2 studies the radiative effects of black carbon (BC), sulfate and organic carbon (OC) internal mixing using a simple radiative transfer model. I find that internal mixing may not result in a positive radiative forcing compared to external mixing, but blocks additional shortwave radiation from the surface, enhancing the surface dimming effect. Chapter 3 estimates the impact of atmospheric aerosol attenuation on solar PV resources in China using a PV performance model with satellite-derived long-term surface irradiance data. I find that, in Eastern China, annual average reductions of solar resources due to aerosols are more than 20%, with comparable impacts to clouds in winter. Improving air quality in China would increase efficiency of solar PV generation. As a positive feedback, increased PV efficiency and deployment would further reduce air pollutant emissions too. Chapter 4 further quantifies the total aerosol impact on PV efficiency globally, including both atmospheric aerosols and the deposition of PM on PV surfaces. I find that, if panels are uncleaned and soiling is only removed by precipitation, deposition of PM accounts for more than two-thirds of the total aerosol impact in most regions. Cleaning the panels, even every few months, would largely increase PV efficiency in resource-abundant regions. Chapter 5 takes a further step to evaluate the impact of PV generation reduction due to aerosols on a projected 2030 power system in China with 400GW of PV. I find that aerosols reduce PV generation by 22% and increase baseload power generation, with almost no additional capacity needed. Due to intermittency of solar generation, 160 GW of backup power is needed to maintain grid stability. However, storage provides an opportunity to reduce the backup power capacity by 66%.

Utility-interactive photovoltaic power conditioners - Effects of transformerless design and dc injection

NASA Astrophysics Data System (ADS)

Das, R.; Krauthamer, S.; Klein, J.

It is shown that the use of isolation transformers to eliminate dc injection into the utility in utility-interactive photovoltaic (PV) systems can reduce the overall efficiency of the system. In order to improve PV efficiency, a transformerless power conditioning subsystem (PCS) is proposed for a grounded PV array having two and three connections to a utility. An additional transformerless PCS configuration is proposed for an ungrounded PV array. A detailed schematic drawing of the interconnections between the elements of a transformerless PCS is provided.

Performance of a Dynamically Controlled Inverter in a Photovoltaic System Interconnected with a Secondary Network Distribution System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coddington, M. H.; Kroposki, B. D.; Basso, T.

In 2008, a 300 kW{sub peak} photovoltaic (PV) system was installed on the rooftop of the Colorado Convention Center (CCC). The installation was unique for the electric utility, Xcel Energy, as it had not previously permitted a PV system to be interconnected on a building served by the local secondary network distribution system (network). The PV system was installed with several provisions; one to prevent reverse power flow, another called a dynamically controlled inverter (DCI), that curtails the output of the PV inverters to maintain an amount of load supplied by Xcel Energy at the CCC. The DCI system utilizesmore » current transformers (CTs) to sense power flow to insure that a minimum threshold is maintained from Xcel Energy through the network transformers. The inverters are set to track the load on each of the three phases and curtail power from the PV system when the generated PV system current reaches 95% of the current on any phase. This is achieved by the DCI, which gathers inputs from current transformers measuring the current from the PV array, Xcel, and the spot network load. Preventing reverse power flow is a critical technical requirement for the spot network which serve this part of the CCC. The PV system was designed with the expectation that the DCI system would not curtail the PV system, as the expected minimum load consumption was historically higher than the designed PV system size. However, the DCI system has operated many days during the course of a year, and the performance has been excellent. The DCI system at the CCC was installed as a secondary measure to insure that a minimum level of power flows to the CCC from the Xcel Energy network. While this DCI system was intended for localized control, the system could also reduce output percent if an external smart grid control signal was employed. This paper specifically focuses on the performance of the innovative design at this installation; however, the DCI system could also be used for new s- art grid-enabled distribution systems where renewables power contributions at certain conditions or times may need to be curtailed.« less

Neuropeptide Y as a possible homeostatic element for changes in cortical excitability induced by repetitive transcranial magnetic stimulation.

PubMed

Jazmati, Danny; Neubacher, Ute; Funke, Klaus

2018-02-24

Repetitive transcranial magnetic stimulation (rTMS) is able to modify cortical excitability. Rat rTMS studies revealed a modulation of inhibitory systems, in particular that of the parvalbumin-expressing (PV+) interneurons, when using intermittent theta-burst stimulation (iTBS). The potential disinhibitory action of iTBS raises the questions of how neocortical circuits stabilize excitatory-inhibitory balance within a physiological range. Neuropeptide Y (NPY) appears to be one candidate. Analysis of cortical expression of PV, NPY and vesicular glutamate transporter type 1 (vGluT1) by immunohistochemical means at the level of cell counts, mean neuropil expression and single cell pre-/postsynaptic expression, with and without intraventricular NPY-injection. Our results show that iTBS not only reduced the number of neurons with high-PV expression in a dose-dependent fashion, but also increased the cortical expression of NPY, discussed to reduce glutamatergic transmission, and this was further associated with a reduced vGluT1 expression, an indicator of glutamateric presynaptic activity. Interneurons showing a low-PV expression exhibit less presynaptic vGluT1 expression compared to those with a high-PV expression. Intraventricular application of NPY prior to iTBS prevented the iTBS-induced reduction in the number of high-PV neurons, the reduction in tissue vGluT1 level and that presynaptic to high-PV cells. We conclude that NPY, possibly via a global but also slow homeostatic control of glutamatergic transmission, modulates the strength and direction of the iTBS effects, likely preventing pathological imbalance of excitatory and inhibitory cortical activity but still allowing enough disinhibition beneficial for plastic changes as during learning. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

The use of peripheral vision to guide perturbation-evoked reach-to-grasp balance-recovery reactions

PubMed Central

King, Emily C.; McKay, Sandra M.; Cheng, Kenneth C.

2016-01-01

For a reach-to-grasp reaction to prevent a fall, it must be executed very rapidly, but with sufficient accuracy to achieve a functional grip. Recent findings suggest that the CNS may avoid potential time delays associated with saccade-guided arm movements by instead relying on peripheral vision (PV). However, studies of volitional arm movements have shown that reaching is slower and/or less accurate when guided by PV, rather than central vision (CV). The present study investigated how the CNS resolves speed-accuracy trade-offs when forced to use PV to guide perturbation-evoked reach-to-grasp balance-recovery reactions. These reactions were evoked, in 12 healthy young adults, via sudden unpredictable anteroposterior platform translation (barriers deterred stepping reactions). In PV trials, subjects were required to look straight-ahead at a visual target while a small cylindrical handhold (length 25%> hand-width) moved intermittently and unpredictably along a transverse axis before stopping at a visual angle of 20°, 30°, or 40°. The perturbation was then delivered after a random delay. In CV trials, subjects fixated on the handhold throughout the trial. A concurrent visuo-cognitive task was performed in 50% of PV trials but had little impact on reach-to-grasp timing or accuracy. Forced reliance on PV did not significantly affect response initiation times, but did lead to longer movement times, longer time-after-peak-velocity and less direct trajectories (compared to CV trials) at the larger visual angles. Despite these effects, forced reliance on PV did not compromise ability to achieve a functional grasp and recover equilibrium, for the moderately large perturbations and healthy young adults tested in this initial study. PMID:20957351

Alternative Sources of Energy for U.S. Air Force Bases

DTIC Science & Technology

2009-08-01

produce power intermittently, with output gaps ranging from minutes—as caused by cloud cover over solar PV systems—or hours, as happens to solar...typically use biomass-to-liquid technology.  Third-generation biofuels use algae or algae products such as oils. Algae provide high- yield feedstocks to...produce several dozen times more energy yield per acre than first-generation feedstocks. The main bottleneck for the production of lignocellulosic

Multiple blocks of intermittent and continuous theta-burst stimulation applied via transcranial magnetic stimulation differently affect sensory responses in rat barrel cortex

PubMed Central

Thimm, Andreas; Funke, Klaus

2015-01-01

Cortical sensory processing varies with cortical state and the balance of inhibition to excitation. Repetitive transcranial magnetic stimulation (rTMS) has been shown to modulate human cortical excitability. In a rat model, we recently showed that intermittent theta-burst stimulation (iTBS) applied to the corpus callosum, to activate primarily supragranular cortical pyramidal cells but fewer subcortical neurons, strongly reduced the cortical expression of parvalbumin (PV), indicating reduced activity of fast-spiking interneurons. Here, we used the well-studied rodent barrel cortex system to test how iTBS and continuous TBS (cTBS) modulate sensory responses evoked by either single or double stimuli applied to the principal (PW) and/or adjacent whisker (AW) in urethane-anaesthetized rats. Compared to sham stimulation, iTBS but not cTBS particularly enhanced late (>18 ms) response components of multi-unit spiking and local field potential responses in layer 4 but not the very early response (<18 ms). Similarly, only iTBS diminished the suppression of the second response evoked by paired PW or AW–PW stimulation at 20 ms intervals. The effects increased with each of the five iTBS blocks applied. With cTBS a mild effect similar to that of iTBS was first evident after 4–5 stimulation blocks. Enhanced cortical c-Fos and zif268 expression but reduced PV and GAD67 expression was found only after iTBS, indicating increased cortical activity due to lowered inhibition. We conclude that iTBS but less cTBS may primarily weaken a late recurrent-type cortical inhibition mediated via a subset of PV+ interneurons, enabling stronger late response components believed to contribute to the perception of sensory events. PMID:25504571

Masked polycythaemia vera: presenting features, response to treatment and clinical outcomes.

PubMed

Alvarez-Larrán, Alberto; Angona, Anna; Ancochea, Agueda; García-Pallarols, Francesc; Fernández, Concepción; Longarón, Raquel; Bellosillo, Beatriz; Besses, Carlos

2016-01-01

Masked polycythaemia vera (PV) has been proposed as a new entity with poorer outcome than overt PV. In this study, the initial clinical and laboratory characteristics, response to treatment and outcome of masked and overt PV were compared using red cell mass and haemoglobin or haematocrit levels for the distinction between both entities. Sixty-eight of 151 PV patients (45%) were classified as masked PV according to World Health Organisation diagnostic criteria, whereas 16 (11%) were classified as masked PV using the British Committee for Standards in Haematology (BCSH). In comparison with overt PV, a higher platelet count and a lower JAK2V617F allele burden at diagnosis were observed in masked PV. Patients with masked PV needed lower phlebotomies and responded faster to hydroxcarbamide than those with overt PV. Complete haematological response was more frequently achieved in masked than in overt PV (79% vs. 58%, P = 0.001). There were no significant differences in the duration of haematological response, the rate of resistance or intolerance to hydroxycarbamide and the probability of molecular response according to type of PV (masked vs. overt). Overall survival, rate of thrombosis and major bleeding, and probability of transformation was superimposable among patients with masked and overt PV. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Influence of Distributed Residential Energy Storage on Voltage in Rural Distribution Network and Capacity Configuration

NASA Astrophysics Data System (ADS)

Liu, Lu; Tong, Yibin; Zhao, Zhigang; Zhang, Xuefen

2018-03-01

Large-scale access of distributed residential photovoltaic (PV) in rural areas has solved the voltage problem to a certain extent. However, due to the intermittency of PV and the particularity of rural residents’ power load, the problem of low voltage in the evening peak remains to be resolved. This paper proposes to solve the problem by accessing residential energy storage. Firstly, the influence of access location and capacity of energy storage on voltage distribution in rural distribution network is analyzed. Secondly, the relation between the storage capacity and load capacity is deduced for four typical load and energy storage cases when the voltage deviation meets the demand. Finally, the optimal storage position and capacity are obtained by using PSO and power flow simulation.

Univariate Time Series Prediction of Solar Power Using a Hybrid Wavelet-ARMA-NARX Prediction Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazaripouya, Hamidreza; Wang, Yubo; Chu, Chi-Cheng

This paper proposes a new hybrid method for super short-term solar power prediction. Solar output power usually has a complex, nonstationary, and nonlinear characteristic due to intermittent and time varying behavior of solar radiance. In addition, solar power dynamics is fast and is inertia less. An accurate super short-time prediction is required to compensate for the fluctuations and reduce the impact of solar power penetration on the power system. The objective is to predict one step-ahead solar power generation based only on historical solar power time series data. The proposed method incorporates discrete wavelet transform (DWT), Auto-Regressive Moving Average (ARMA)more » models, and Recurrent Neural Networks (RNN), while the RNN architecture is based on Nonlinear Auto-Regressive models with eXogenous inputs (NARX). The wavelet transform is utilized to decompose the solar power time series into a set of richer-behaved forming series for prediction. ARMA model is employed as a linear predictor while NARX is used as a nonlinear pattern recognition tool to estimate and compensate the error of wavelet-ARMA prediction. The proposed method is applied to the data captured from UCLA solar PV panels and the results are compared with some of the common and most recent solar power prediction methods. The results validate the effectiveness of the proposed approach and show a considerable improvement in the prediction precision.« less

Energy efficiency design strategies for buildings with grid-connected photovoltaic systems

NASA Astrophysics Data System (ADS)

Yimprayoon, Chanikarn

The building sector in the United States represents more than 40% of the nation's energy consumption. Energy efficiency design strategies and renewable energy are keys to reduce building energy demand. Grid-connected photovoltaic (PV) systems installed on buildings have been the fastest growing market in the PV industry. This growth poses challenges for buildings qualified to serve in this market sector. Electricity produced from solar energy is intermittent. Matching building electricity demand with PV output can increase PV system efficiency. Through experimental methods and case studies, computer simulations were used to investigate the priorities of energy efficiency design strategies that decreased electricity demand while producing load profiles matching with unique output profiles from PV. Three building types (residential, commercial, and industrial) of varying sizes and use patterns located in 16 climate zones were modeled according to ASHRAE 90.1 requirements. Buildings were analyzed individually and as a group. Complying with ASHRAE energy standards can reduce annual electricity consumption at least 13%. With energy efficiency design strategies, the reduction could reach up to 65%, making it possible for PV systems to meet reduced demands in residential and industrial buildings. The peak electricity demand reduction could be up to 71% with integration of strategies and PV. Reducing lighting power density was the best single strategy with high overall performances. Combined strategies such as zero energy building are also recommended. Electricity consumption reductions are the sum of the reductions from strategies and PV output. However, peak electricity reductions were less than their sum because they reduced peak at different times. The potential of grid stress reduction is significant. Investment incentives from government and utilities are necessary. The PV system sizes on net metering interconnection should not be limited by legislation existing in some states. Data from this study provides insight of impacts from applying energy efficiency design strategies in buildings with grid-connected PV systems. With the current transition from traditional electric grids to future smart grids, this information plus large database of various building conditions allow possible investigations needed by governments or utilities in large scale communities for implementing various measures and policies.

Suitability of representative electrochemical energy storage technologies for ramp-rate control of photovoltaic power

NASA Astrophysics Data System (ADS)

Jiang, Yu; Fletcher, John; Burr, Patrick; Hall, Charles; Zheng, Bowen; Wang, Da-Wei; Ouyang, Zi; Lennon, Alison

2018-04-01

Photovoltaic (PV) systems can exhibit rapid variances in their power output due to irradiance changes which can destabilise an electricity grid. This paper presents a quantitative comparison of the suitability of different electrochemical energy storage system (ESS) technologies to provide ramp-rate control of power in PV systems. Our investigations show that, for PV systems ranging from residential rooftop systems to megawatt power systems, lithium-ion batteries with high energy densities (up to 600 Wh L-1) require the smallest power-normalised volumes to achieve the ramp rate limit of 10% min-1 with 100% compliance. As the system size increases, the ESS power-normalised volume requirements are significantly reduced due to aggregated power smoothing, with high power lithium-ion batteries becoming increasingly more favourable with increased PV system size. The possibility of module-level ramp-rate control is also introduced, and results show that achievement of a ramp rate of 10% min-1 with 100% compliance with typical junction box sizes will require ESS energy and power densities of 400 Wh L-1 and 2300 W L-1, respectively. While module-level ramp-rate control can reduce the impact of solar intermittence, the requirement is challenging, especially given the need for low cost and long cycle life.

Causal Evidence for the Role of Specific GABAergic Interneuron Types in Entorhinal Recruitment of Dentate Granule Cells

PubMed Central

Lee, Cheng-Ta; Kao, Min-Hua; Hou, Wen-Hsien; Wei, Yu-Ting; Chen, Chin-Lin; Lien, Cheng-Chang

2016-01-01

The dentate gyrus (DG) is the primary gate of the hippocampus and controls information flow from the cortex to the hippocampus proper. To maintain normal function, granule cells (GCs), the principal neurons in the DG, receive fine-tuned inhibition from local-circuit GABAergic inhibitory interneurons (INs). Abnormalities of GABAergic circuits in the DG are associated with several brain disorders, including epilepsy, autism, schizophrenia, and Alzheimer disease. Therefore, understanding the network mechanisms of inhibitory control of GCs is of functional and pathophysiological importance. GABAergic inhibitory INs are heterogeneous, but it is unclear how individual subtypes contribute to GC activity. Using cell-type-specific optogenetic perturbation, we investigated whether and how two major IN populations defined by parvalbumin (PV) and somatostatin (SST) expression, regulate GC input transformations. We showed that PV-expressing (PV+) INs, and not SST-expressing (SST+) INs, primarily suppress GC responses to single cortical stimulation. In addition, these two IN classes differentially regulate GC responses to θ and γ frequency inputs from the cortex. Notably, PV+ INs specifically control the onset of the spike series, whereas SST+ INs preferentially regulate the later spikes in the series. Together, PV+ and SST+ GABAergic INs engage differentially in GC input-output transformations in response to various activity patterns. PMID:27830729

Fuzzy-driven energy storage system for mitigating voltage unbalance factor on distribution network with photovoltaic system

NASA Astrophysics Data System (ADS)

Wong, Jianhui; Lim, Yun Seng; Morris, Stella; Morris, Ezra; Chua, Kein Huat

2017-04-01

The amount of small-scaled renewable energy sources is anticipated to increase on the low-voltage distribution networks for the improvement of energy efficiency and reduction of greenhouse gas emission. The growth of the PV systems on the low-voltage distribution networks can create voltage unbalance, voltage rise, and reverse-power flow. Usually these issues happen with little fluctuation. However, it tends to fluctuate severely as Malaysia is a region with low clear sky index. A large amount of clouds often passes over the country, hence making the solar irradiance to be highly scattered. Therefore, the PV power output fluctuates substantially. These issues can lead to the malfunction of the electronic based equipment, reduction in the network efficiency and improper operation of the power protection system. At the current practice, the amount of PV system installed on the distribution network is constraint by the utility company. As a result, this can limit the reduction of carbon footprint. Therefore, energy storage system is proposed as a solution for these power quality issues. To ensure an effective operation of the distribution network with PV system, a fuzzy control system is developed and implemented to govern the operation of an energy storage system. The fuzzy driven energy storage system is able to mitigate the fluctuating voltage rise and voltage unbalance on the electrical grid by actively manipulates the flow of real power between the grid and the batteries. To verify the effectiveness of the proposed fuzzy driven energy storage system, an experimental network integrated with 7.2kWp PV system was setup. Several case studies are performed to evaluate the response of the proposed solution to mitigate voltage rises, voltage unbalance and reduce the amount of reverse power flow under highly intermittent PV power output.

Market Transformation Pathways for Grid-Connected Rooftop Solar PV in Minnesota

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abbey, Ross; Ross, Brian

2013-06-03

This report presents the market and policy findings of the Minnesota Solar Challenge program. The report draws on information collected from state agencies, local government units, solar industry participants, rooftop photovoltaic (PV) adopters (sometimes called customer-generators), state and national experts, the Commerce distributed generation stakeholder process, and the numerous reports and data sets referenced herein.

Intermittent Preventive Treatment for Malaria in Papua New Guinean Infants Exposed to Plasmodium falciparum and P. vivax: A Randomized Controlled Trial

PubMed Central

Stanisic, Danielle I.; Robinson, Leanne; Barnadas, Céline; Manong, Doris; Salib, Mary; Iga, Jonah; Tarongka, Nandao; Ley, Serej; Rosanas-Urgell, Anna; Aponte, John J.; Zimmerman, Peter A.; Beeson, James G.; Schofield, Louis; Siba, Peter; Rogerson, Stephen J.; Reeder, John C.; Mueller, Ivo

2012-01-01

Background Intermittent preventive treatment in infants (IPTi) has been shown in randomized trials to reduce malaria-related morbidity in African infants living in areas of high Plasmodium falciparum (Pf) transmission. It remains unclear whether IPTi is an appropriate prevention strategy in non-African settings or those co-endemic for P. vivax (Pv). Methods and Findings In this study, 1,121 Papua New Guinean infants were enrolled into a three-arm placebo-controlled randomized trial and assigned to sulfadoxine-pyrimethamine (SP) (25 mg/kg and 1.25 mg/kg) plus amodiaquine (AQ) (10 mg/kg, 3 d, n = 374), SP plus artesunate (AS) (4 mg/kg, 3 d, n = 374), or placebo (n = 373), given at 3, 6, 9 and 12 mo. Both participants and study teams were blinded to treatment allocation. The primary end point was protective efficacy (PE) against all episodes of clinical malaria from 3 to 15 mo of age. Analysis was by modified intention to treat. The PE (compared to placebo) against clinical malaria episodes (caused by all species) was 29% (95% CI, 10–43, p≤0.001) in children receiving SP-AQ and 12% (95% CI, −11 to 30, p = 0.12) in those receiving SP-AS. Efficacy was higher against Pf than Pv. In the SP-AQ group, Pf incidence was 35% (95% CI, 9–54, p = 0.012) and Pv incidence was 23% (95% CI, 0–41, p = 0.048) lower than in the placebo group. IPTi with SP-AS protected only against Pf episodes (PE = 31%, 95% CI, 4–51, p = 0.027), not against Pv episodes (PE = 6%, 95% CI, −24 to 26, p = 0.759). Number of observed adverse events/serious adverse events did not differ between treatment arms (p>0.55). None of the serious adverse events were thought to be treatment-related, and the vomiting rate was low in both treatment groups (1.4%–2.0%). No rebound in malaria morbidity was observed for 6 mo following the intervention. Conclusions IPTi using a long half-life drug combination is efficacious for the prevention of malaria and anemia in infants living in a region highly endemic for both Pf and Pv. Trial registration ClinicalTrials.gov NCT00285662 Please see later in the article for the Editors' Summary PMID:22479155

Electricity Market Liberalisation and Flexibility of Conventional Generation to Balance Intermittent Renewable Energy - Is It Possible to Stay Competitive?

NASA Astrophysics Data System (ADS)

Linkevics, O.; Ivanova, P.; Balodis, M.

2016-12-01

Intermittent generation (solar PV and wind energy) integration in power production portfolio as well as electricity price fluctuations have changed the running manner of conventional combined heat and power (CHP) plants: the shift from base load operation to running in cyclic modes. These cogeneration power plants are not adapted to new running conditions. The level of CHP plant flexibility should be improved to operate profitably and efficiently from both technical and fuel usage point of view. There are different ways to increase the flexibility of power plants. Before any improvements, the situation at power plants should be evaluated and the weakest points defined. In this publication, such measures are presented on Riga CHP-2 plant example: installation of heat storage tank; extension of operation rang; acceleration of start-ups.

Hypervolemia During Drinking of ISO and Hypertonic Fluids by Men at Rest and Exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Looft-Wilson, R.; Wisherd, J. L.; Fung, P. P.; Erti, A. C.; Jackson, C. G. R.; Barnes, P. R.; Wong, L. G.

1994-01-01

To test the hypothesis that drink composition is more important than osmolality (osm) for maintaining and increasing plasma vol. (PV, hypervolemia) at rest and exercise (21.8C Tdb, 50% rh), 6 men (22-39 vr) underwent six treatments while sitting for 90 min (0.39 l/min) followed by 70 min of sitting ergometer exercise (2.08 l/min, 70%vO2 peak). Resting, intermittent drinking (10 ml/kg, 768 ml) beverages were: P1 (20 mEq Na+, 365 mosmol/kg), P2 (40 mEq Na+. 791 mosm), P2G (40 mEq Na+, 80 ml glycerol, 1.392 mosm). AA (157 mEq Na+, 253 mosm), and 01 and 02 (nothing). The exercise drink (10 ml/kg, 768 ml) was P1 for all experiments, except 02 (nothing). Resting % delta PV (Hb-Hct) increased (P<0.05) by 3-6% only with P2 and AA, respectively, Exercise % delta PV was + 1 to + 3% (NS) with AA, -6% to 0% (KS) with P1, P2. P2G, and 01,and 8% to -5% (P<0.05) with 02- Thus, AA with 157 mEq Na+ and the lowest osmolality maintained PV at rest and exercise, while the other beverages with low Na+ and higher osmolality (365 to 1.382 mosm) did not.

A frequency-based window width optimized two-dimensional S-Transform profilometry

NASA Astrophysics Data System (ADS)

Zhong, Min; Chen, Feng; Xiao, Chao

2017-11-01

A new scheme is proposed to as a frequency-based window width optimized two-dimensional S-Transform profilometry, in which parameters pu and pv are introduced to control the width of a two-dimensional Gaussian window. Unlike the standard two-dimensional S-transform using the Gaussian window with window width proportional to the reciprocal local frequency of the tested signal, the size of window width for the optimized two-dimensional S-Transform varies with the pu th (pv th) power of the reciprocal local frequency fx (fy) in x (y) direction. The paper gives a detailed theoretical analysis of optimized two-dimensional S-Transform in fringe analysis as well as the characteristics of the modified Gauss window. Simulations are applied to evaluate the proposed scheme, the results show that the new scheme has better noise reduction ability and can extract phase distribution more precise in comparison with the standard two-dimensional S-transform even though the surface of the measured object varies sharply. Finally, the proposed scheme is demonstrated on three-dimensional surface reconstruction for a complex plastic cat mask to show its effectiveness.

Survey of International Space Station Charging Events

NASA Technical Reports Server (NTRS)

Craven, P. D.; Wright, Kenneth H., Jr.; Minow, Joseph I.; Coffey, Victoria N.; Schneider, Todd A.; Vaughn, Jason A.; Ferguson, Dale C.; Parker, Linda N.

2009-01-01

With the negative grounding of the 160V Photovoltaic (PV) arrays, the International Space Station (ISS) can experience varied and interesting charging events. Since August 2006, there has been a multi-probe p ackage, called the Floating Potential Measurement Unit (FPMU), availa ble to provide redundant measurements of the floating potential of th e ISS as well as the density and temperature of the local plasma environment. The FPMU has been operated during intermittent data campaigns since August 2006 and has collected over 160 days of information reg arding the charging of the ISS as it has progressed in configuration from one to three PV arrays and with various additional modules such as the European Space Agency?s Columbus laboratory and the Japan Aeros pace Exploration Agency's Kibo laboratory. This paper summarizes the charging of the ISS and the local environmental conditions that contr ibute to those charging events, both as measured by the FPMU.

Surplus from and storage of electricity generated by intermittent sources

NASA Astrophysics Data System (ADS)

Wagner, Friedrich

2016-12-01

Data from the German electricity system for the years 2010, 2012, 2013, and 2015 are used and scaled up to a 100% supply by intermittent renewable energy sources (iRES). In the average, 330GW wind and PV power are required to meet this 100% target. A back-up system is necessary with the power of 89% of peak load. Surplus electricity accrues at high power levels. Curtailing surplus power to a large extent is found to be uneconomic. Demand-side management will suffer from the strong day-to-day variation of available surplus energy. A day storage is ineffective because of the day-night correlation of surplus power during winter. A seasonal storage loses its character when transformation losses are considered because it can contribute only after periods with excessive surplus production. The option of an oversized iRES system to feed the storage is also not effective because, in this case, energy can be taken directly from the large iRES supply, making storage superfluous. The capacities to be installed stress the difficulty to base heat supply and mobility also on iRES generated electricity in the future. As the German energy transition replaces one CO2-free electricity supply system by another one, no major reduction in CO2 emission can be expected till 2022, when the last nuclear reactor will be switched off. By 2022, an extremely oversized power supply system has to be created, which can be expected to continue running down spot-market electricity prices. The continuation of the economic response -to replace expensive gas fuel by cheap lignite- causes an overall increase in CO2 emission. The German GHG emission targets for 2020 and beyond are therefore in jeopardy.

Revolution…Now The Future Arrives for Five Clean Energy Technologies – 2015 Update

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

In 2013, the U.S. Department of Energy (DOE) released the Revolution Now report, highlighting four transformational technologies: land-based wind power, silicon photovoltaic (PV) solar modules, light-emitting diodes (LEDs), and electric vehicles (EVs). That study and its 2014 update showed how dramatic reductions in cost are driving a surge in consumer, industrial, and commercial adoption for these clean energy technologies—as well as yearly progress. In addition to presenting the continued progress made over the last year in these areas, this year’s update goes further. Two separate sections now cover large, central, utility-scale PV plants and smaller, rooftop, distributed PV systems tomore » highlight how both have achieved significant deployment nationwide, and have done so through different innovations, such as easier access to capital for utility-scale PV and reductions of non-hardware costs and third-party ownership for distributed PV. Along with these core technologies« less

A proposed adaptive step size perturbation and observation maximum power point tracking algorithm based on photovoltaic system modeling

NASA Astrophysics Data System (ADS)

Huang, Yu

Solar energy becomes one of the major alternative renewable energy options for its huge abundance and accessibility. Due to the intermittent nature, the high demand of Maximum Power Point Tracking (MPPT) techniques exists when a Photovoltaic (PV) system is used to extract energy from the sunlight. This thesis proposed an advanced Perturbation and Observation (P&O) algorithm aiming for relatively practical circumstances. Firstly, a practical PV system model is studied with determining the series and shunt resistances which are neglected in some research. Moreover, in this proposed algorithm, the duty ratio of a boost DC-DC converter is the object of the perturbation deploying input impedance conversion to achieve working voltage adjustment. Based on the control strategy, the adaptive duty ratio step size P&O algorithm is proposed with major modifications made for sharp insolation change as well as low insolation scenarios. Matlab/Simulink simulation for PV model, boost converter control strategy and various MPPT process is conducted step by step. The proposed adaptive P&O algorithm is validated by the simulation results and detail analysis of sharp insolation changes, low insolation condition and continuous insolation variation.

Dioxygen in Polyoxometalate Mediated Reactions.

PubMed

Weinstock, Ira A; Schreiber, Roy E; Neumann, Ronny

2018-03-14

In this review article, we consider the use of molecular oxygen in reactions mediated by polyoxometalates. Polyoxometalates are anionic metal oxide clusters of a variety of structures that are soluble in liquid phases and therefore amenable to homogeneous catalytic transformations. Often, they are active for electron transfer oxidations of a myriad of substrates and upon reduction can be reoxidized by molecular oxygen. For example, the phosphovanadomolybdate, H 5 PV 2 Mo 10 O 40 , can oxidize Pd(0) thereby enabling aerobic reactions catalyzed by Pd and H 5 PV 2 Mo 10 O 40 . In a similar vein, polyoxometalates can stabilize metal nanoparticles, leading to additional transformations. Furthermore, electron transfer oxidation of other substrates such as halides and sulfur-containing compounds is possible. More uniquely, H 5 PV 2 Mo 10 O 40 and its analogues can mediate electron transfer-oxygen transfer reactions where oxygen atoms are transferred from the polyoxometalate to the substrate. This unique property has enabled correspondingly unique transformations involving carbon-carbon, carbon-hydrogen, and carbon-metal bond activation. The pathway for the reoxidation of vanadomolybdates with O 2 appears to be an inner-sphere reaction, but the oxidation of one-electron reduced polyoxotungstates has been shown through intensive research to be an outer-sphere reaction. Beyond electron transfer and electron transfer-oxygen transfer aerobic transformations, there a few examples of apparent dioxygenase activity where both oxygen atoms are donated to a substrate.

Intermittent/transient faults in digital systems

NASA Technical Reports Server (NTRS)

Masson, G. M.; Glazer, R. E.

1982-01-01

Containment set techniques are applied to 8085 microprocessor controllers so as to transform a typical control system into a slightly modified version, shown to be crashproof: after the departure of the intermittent/transient fault, return to one proper control algorithm is assured, assuming no permanent faults occur.

Structural and physical properties of the dust particles in Qatar and their influence on the PV panel performance.

PubMed

Aïssa, Brahim; Isaifan, Rima J; Madhavan, Vinod E; Abdallah, Amir A

2016-08-16

Recently, extensive R&D has been conducted, both by industry and academia, to significantly raise the conversion efficiency of commercial photovoltaic (PV) modules. The installation of PV systems aimed at optimizing solar energy yield is primarily dictated by its geographic location and installation design to maximize solar exposure. However, even when these characteristics have been addressed appropriately, there are other factors that adversely affect the performance of PV systems, namely the temperature-induced voltage decrease leading to a PV power loss, and the dust accumulation (soiling). The latter is the lesser acknowledged factor that significantly influences the performance of PV installations especially in the Middle East region. In this paper we report on the investigation of the structural and physical properties of the desert-dust particles in the State of Qatar. The dust particles were collected directly from the PV panels installed in desert environment and characterized by different techniques, including scanning electron, optical and atomic force microscopies, X-ray diffraction, energy-dispersive, UV-Vis, micro-Raman and Fourier transform infrared spectroscopy. The vibrating sample magnetometry analyses were also conducted to study the magnetic properties of the dust particles. The influence of the dust accumulation on the PV panel performance was also presented and discussed.

Structural and physical properties of the dust particles in Qatar and their influence on the PV panel performance

NASA Astrophysics Data System (ADS)

Aïssa, Brahim; Isaifan, Rima J.; Madhavan, Vinod E.; Abdallah, Amir A.

2016-08-01

Recently, extensive R&D has been conducted, both by industry and academia, to significantly raise the conversion efficiency of commercial photovoltaic (PV) modules. The installation of PV systems aimed at optimizing solar energy yield is primarily dictated by its geographic location and installation design to maximize solar exposure. However, even when these characteristics have been addressed appropriately, there are other factors that adversely affect the performance of PV systems, namely the temperature-induced voltage decrease leading to a PV power loss, and the dust accumulation (soiling). The latter is the lesser acknowledged factor that significantly influences the performance of PV installations especially in the Middle East region. In this paper we report on the investigation of the structural and physical properties of the desert-dust particles in the State of Qatar. The dust particles were collected directly from the PV panels installed in desert environment and characterized by different techniques, including scanning electron, optical and atomic force microscopies, X-ray diffraction, energy-dispersive, UV-Vis, micro-Raman and Fourier transform infrared spectroscopy. The vibrating sample magnetometry analyses were also conducted to study the magnetic properties of the dust particles. The influence of the dust accumulation on the PV panel performance was also presented and discussed.

On-off intermittency in time series of spontaneous paroxysmal activity in rats with genetic absence epilepsy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hramov, Alexander; Koronovskii, Alexey A.; Midzyanovskaya, I.S.

2006-12-15

In the present paper we consider the on-off intermittency phenomena observed in time series of spontaneous paroxysmal activity in rats with genetic absence epilepsy. The method to register and analyze the electroencephalogram with the help of continuous wavelet transform is also suggested.

Testing the PV-Theta Mapping Technique in a 3-D CTM Model Simulation

NASA Technical Reports Server (NTRS)

Frith, Stacey M.

2004-01-01

Mapping lower stratospheric ozone into potential vorticity (PV)- potential temperature (Theta) coordinates is a common technique employed to analyze sparse data sets. Ozone transformed into a flow-following dynamical coordinate system is insensitive to meteorological variations. Therefore data from a wide range of times/locations can be compared, so long as the measurements were made in the same airmass (as defined by PV). Moreover, once a relationship between ozone and PV/Theta is established, a full 3D ozone field can be estimated from this relationship and the 3D analyzed PV field. However, ozone data mapped in this fashion can be hampered by noisy PV fields, or "mis-matches" in the resolution and/or exact location of the ozone and PV measurements. In this study, we investigate the PV-ozone relationship using output from a recent 50-year run of the Goddard 3D chemical transport model (CTM). Model constituents are transported using off-line dynamics from the finite volume general circulation model (FVGCM). By using the internally consistent model PV and ozone fields, we minimize noise due to mis-matching and resolution issues. We calculate correlations between model ozone and PV throughout the stratosphere, and test the sensitivity of the technique to initial data resolution. To do this we degrade the model data to that of various satellite instruments, then compare the mapped fields derived from the sub-sampled data to the full resolution model data. With these studies we can determine appropriate limits for the PV-theta mapping technique in latitude, altitude, and as a function of original data resolution.

Sub-synchronous resonance damping using high penetration PV plant

NASA Astrophysics Data System (ADS)

Khayyatzadeh, M.; Kazemzadeh, R.

2017-02-01

The growing need to the clean and renewable energy has led to the fast development of transmission voltage-level photovoltaic (PV) plants all over the world. These large scale PV plants are going to be connected to power systems and one of the important subjects that should be investigated is the impact of these plants on the power system stability. Can large scale PV plants help to damp sub-synchronous resonance (SSR) and how? In this paper, this capability of a large scale PV plant is investigated. The IEEE Second Benchmark Model aggregated with a PV plant is utilized as the case study. A Wide Area Measurement System (WAMS) based conventional damping controller is designed and added to the main control loop of PV plant in order to damp the SSR and also investigation of the destructive effect of time delay in remote feedback signal. A new optimization algorithm called teaching-learning-based-optimization (TLBO) algorithm has been used for managing the optimization problems. Fast Furrier Transformer (FFT) analysis and also transient simulations of detailed nonlinear system are considered to investigate the performance of the controller. Robustness of the proposed system has been analyzed by facing the system with disturbances leading to significant changes in generator and power system operating point, fault duration time and PV plant generated power. All the simulations are carried out in MATLAB/SIMULINK environment.

Transforming properties of Felis catus papillomavirus type 2 E6 and E7 putative oncogenes in vitro and their transcriptional activity in feline squamous cell carcinoma in vivo

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altamura, Gennaro, E-mail: gennaro.altamura@unina.it; Corteggio, Annunziata, E-mail: ancorteg@unina.it; Pacini, Laura, E-mail: PaciniL@students.iarc.fr

Felis catus papillomavirus type 2 (FcaPV2) DNA is found in feline cutaneous squamous cell carcinomas (SCCs); however, its biological properties are still uncharacterized. In this study, we successfully expressed FcaPV2 E6 and E7 putative oncogenes in feline epithelial cells and demonstrated that FcaPV2 E6 binds to p53, impairing its protein level. In addition, E6 and E7 inhibited ultraviolet B (UVB)-triggered accumulation of p53, p21 and pro-apoptotic markers such as Cleaved Caspase3, Bax and Bak, suggesting a synergistic action of the virus with UV exposure in tumour pathogenesis. Furthermore, FcaPV2 E7 bound to feline pRb and impaired pRb levels, resulting inmore » upregulation of the downstream pro-proliferative genes Cyclin A and Cdc2. Importantly, we demonstrated mRNA expression of FcaPV2 E2, E6 and E7 in feline SCC samples, strengthening the hypothesis of a causative role in the development of feline SCC. - Highlights: • FcaPV2 E6 binds to and deregulates feline p53 protein. • FcaPV2 E7 binds to and deregulates feline pRb protein. • FcaPV2 oncogenes inhibit UVB-induced apoptosis. • FcaPV2 E6E7 and E7 increase the lifespan of primary cells. • FcaPV2 E2, E6 and E7 are expressed at the mRNA level in feline SCC in vivo.« less

Real-Time Local Volt/VAR Control Under External Disturbances with High PV Penetration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singhal, A.; Ajjarapu, V.; Fuller, Jason C.

Volt/var control (VVC) of smart PV inverter is becoming one of the most popular solutions to address the voltage challenges associated with high PV penetration. This work focuses on the local droop VVC recommended by the grid integration standards IEEE1547, rule21 and addresses their major challenges i.e. appropriate parameters selection under changing conditions, and the control being vulnerable to instability (or voltage oscillations) and significant steady state error (SSE). This is achieved by proposing a two-layer local real-time adaptive VVC that has two major features i.e. a) it is able to ensure both low SSE and control stability simultaneously withoutmore » compromising either; and b) it dynamically adapts its parameters to ensure good performance in a wide range of external disturbances such as sudden cloud cover, cloud intermittency, and substation voltage changes. A theoretical analysis and convergence proof of the proposed control is also discussed. The proposed control is implementation friendly as it fits well within the integration standard framework and depends only on the local bus information. Furthermore, the performance is compared with the existing droop VVC methods in several scenarios on a large unbalanced 3-phase feeder with detailed secondary side modeling.« less

Real-Time Local Volt/VAR Control Under External Disturbances with High PV Penetration

DOE PAGES

Singhal, A.; Ajjarapu, V.; Fuller, Jason C.; ...

2018-05-28

Volt/var control (VVC) of smart PV inverter is becoming one of the most popular solutions to address the voltage challenges associated with high PV penetration. This work focuses on the local droop VVC recommended by the grid integration standards IEEE1547, rule21 and addresses their major challenges i.e. appropriate parameters selection under changing conditions, and the control being vulnerable to instability (or voltage oscillations) and significant steady state error (SSE). This is achieved by proposing a two-layer local real-time adaptive VVC that has two major features i.e. a) it is able to ensure both low SSE and control stability simultaneously withoutmore » compromising either; and b) it dynamically adapts its parameters to ensure good performance in a wide range of external disturbances such as sudden cloud cover, cloud intermittency, and substation voltage changes. A theoretical analysis and convergence proof of the proposed control is also discussed. The proposed control is implementation friendly as it fits well within the integration standard framework and depends only on the local bus information. Furthermore, the performance is compared with the existing droop VVC methods in several scenarios on a large unbalanced 3-phase feeder with detailed secondary side modeling.« less

Performance assessment of the PNM Prosperity electricity storage project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberson, Dakota; Ellison, James F.; Bhatnagar, Dhruv

2014-05-01

The purpose of this study is to characterize the technical performance of the PNM Prosperity electricity storage project, and to identify lessons learned that can be used to improve similar projects in the future. The PNM Prosperity electricity storage project consists of a 500 kW/350 kWh advanced lead-acid battery with integrated supercapacitor (for energy smoothing) and a 250 kW/1 MWh advanced lead-acid battery (for energy shifting), and is co-located with a 500 kW solar photovoltaic (PV) resource. The project received American Reinvestment and Recovery Act (ARRA) funding. The smoothing system is e ective in smoothing intermittent PV output. The shiftingmore » system exhibits good round-trip efficiencies, though the AC-to-AC annual average efficiency is lower than one might hope. Given the current utilization of the smoothing system, there is an opportunity to incorporate additional control algorithms in order to increase the value of the energy storage system.« less

Solar on the Rise: How Cost Declines and Grid Integration Shape Solar's Growth Potential in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cole, Wesley J; Denholm, Paul L; Feldman, David J

During the past decade, solar power has experienced transformative price declines, enabling it to become a viable electricity source that is supplying 1% of U.S. and world electricity. Further cost reductions are expected to enable substantially greater solar deployment, and new Department of Energy cost targets for utility-scale photovoltaics (PV) and concentrating solar thermal power are $0.03/kW h and $0.05/kW h by 2030, respectively. However, cost reductions are no longer the only significant challenge for PV - addressing grid integration challenges and increasing grid flexibility are critical as the penetration of PV electricity on the grid increases. The development ofmore » low cost energy storage is particularly synergistic with low cost PV, as cost declines in each technology are expected to support greater market opportunities for the other.« less

Identification and characterization of new designer drug 4-fluoro-PV9 and α-PHP in the seized materials.

PubMed

Majchrzak, Milena; Rojkiewicz, Marcin; Celiński, Rafał; Kuś, Piotr; Sajewicz, Mieczysław

In this study, we present identification and physicochemical characterization of new cathinone derivatives, 4-fluoro-PV9 and already known α-PHP in seized materials. Although the disclosure of α-PHP from an illegal product had been reported and characterized to some extent, the data on α-PHP are also presented together with those of 4-fluoro-PV9. The data of characterization for the two compounds were obtained by high-performance liquid chromatography (HPLC)-mass spectrometry and HPLC-diode array detection, electrospray ionization/ion trap mass spectrometry in MS 2 and MS 3 modes, gas chromatography-mass spectrometry, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, and nuclear magnetic resonance spectroscopy. To our knowledge, this is the first report for identification and detailed characterization of 4-fluoro-PV9 circulated on the illegal drug market.

Reducing Demand Charges and Onsite Generation Variability Using Behind-the-Meter Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattarai, Bishnu P.; Myers, Kurt S.; Bush, Jason W.

Electric utilities in the United States are increasingly employing demand charges and/or real-time pricing. This directive is bringing potential opportunities in deploying behindthe-meter energy storage (BMES) systems for various grid functionalities. This study quantifies techno-economic benefits of BMES in reducing demand charge and smoothing load/generation intermittencies, and determines how those benefits vary with onsite distributed photovoltaic. We proposed a two-stage control algorithm, whereby the first stage proactively determines costoptimal BMES configuration for reducing peak-demands and demand charges, and the second stage adaptively compensates intermittent generations and short load spikes that may otherwise increase the demand charges. The performance of themore » proposed algorithm is evaluated through a 24 hours time sweep simulation performed using data from smart microgrid testbed at Idaho National Laboratory (INL). The simulation results demonstrated that this research provides a simple but effective solution for peak shaving, demand charge reductions, and smoothing onsite PV variability.« less

The evolution of AAOE observed constituents with the polar vortex

NASA Technical Reports Server (NTRS)

Schoeberl, Mark R.; Lait, Leslie R.; Newman, P. A.; Martin, R.; Loewenstein, M.; Podolske, J. R.; Anderson, J.; Proffitt, M. H.

1988-01-01

One of the difficulties in determining constituent trends from the ER-2 flight data is the large amount of day to day variability generated by the motion of the polar vortex. To reduce this variability, the observations have been transformed into the conservative (Lagrangian) reference frames consisting of the coordinate pairs, potential temperature (PT) and potential vorticity (PV), or PT and N2O. The requirement of only two independent coordinates rests on the assumption that constituent distributions and their chemical processes are nearly zonal in that coordinate system. Flight data is used everywhere for these transformation except for potential vorticity. Potential vorticity is determined from level flight segments, and NMC PV values during flight dives and takeoffs are combined with flight data in a smooth fashion.

Bidding strategy for microgrid in day-ahead market based on hybrid stochastic/robust optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Guodong; Xu, Yan; Tomsovic, Kevin

In this paper, we propose an optimal bidding strategy in the day-ahead market of a microgrid consisting of intermittent distributed generation (DG), storage, dispatchable DG and price responsive loads. The microgrid coordinates the energy consumption or production of its components and trades electricity in both the day-ahead and real-time markets to minimize its operating cost as a single entity. The bidding problem is challenging due to a variety of uncertainties, including power output of intermittent DG, load variation, day-ahead and real-time market prices. A hybrid stochastic/robust optimization model is proposed to minimize the expected net cost, i.e., expected total costmore » of operation minus total benefit of demand. This formulation can be solved by mixed integer linear programming. The uncertain output of intermittent DG and day-ahead market price are modeled via scenarios based on forecast results, while a robust optimization is proposed to limit the unbalanced power in real-time market taking account of the uncertainty of real-time market price. Numerical simulations on a microgrid consisting of a wind turbine, a PV panel, a fuel cell, a micro-turbine, a diesel generator, a battery and a responsive load show the advantage of stochastic optimization in addition to robust optimization.« less

Bidding strategy for microgrid in day-ahead market based on hybrid stochastic/robust optimization

DOE PAGES

Liu, Guodong; Xu, Yan; Tomsovic, Kevin

2016-01-01

In this paper, we propose an optimal bidding strategy in the day-ahead market of a microgrid consisting of intermittent distributed generation (DG), storage, dispatchable DG and price responsive loads. The microgrid coordinates the energy consumption or production of its components and trades electricity in both the day-ahead and real-time markets to minimize its operating cost as a single entity. The bidding problem is challenging due to a variety of uncertainties, including power output of intermittent DG, load variation, day-ahead and real-time market prices. A hybrid stochastic/robust optimization model is proposed to minimize the expected net cost, i.e., expected total costmore » of operation minus total benefit of demand. This formulation can be solved by mixed integer linear programming. The uncertain output of intermittent DG and day-ahead market price are modeled via scenarios based on forecast results, while a robust optimization is proposed to limit the unbalanced power in real-time market taking account of the uncertainty of real-time market price. Numerical simulations on a microgrid consisting of a wind turbine, a PV panel, a fuel cell, a micro-turbine, a diesel generator, a battery and a responsive load show the advantage of stochastic optimization in addition to robust optimization.« less

Multiple blocks of intermittent and continuous theta-burst stimulation applied via transcranial magnetic stimulation differently affect sensory responses in rat barrel cortex.

PubMed

Thimm, Andreas; Funke, Klaus

2015-02-15

Theta-burst stimulation (TBS) applied via transcranial magnetic stimulation is able to modulate human cortical excitability. Here we investigated in a rat model how two different forms of TBS, intermittent (iTBS) and continuous (cTBS), affect sensory responses in rat barrel cortex. We found that iTBS but less cTBS promoted late (>18 ms) sensory response components while not affecting the earliest response (8-18 ms). The effect increased with each of the five iTBS blocks applied. cTBS somewhat reduced the early response component after the first block but had a similar effect as iTBS after four to five blocks. We conclude that iTBS primarly modulates the activity of (inhibitory) cortical interneurons while cTBS may first reduce general neuronal excitability with a single block but reverse to iTBS-like effects with application of several blocks. Cortical sensory processing varies with cortical state and the balance of inhibition to excitation. Repetitive transcranial magnetic stimulation (rTMS) has been shown to modulate human cortical excitability. In a rat model, we recently showed that intermittent theta-burst stimulation (iTBS) applied to the corpus callosum, to activate primarily supragranular cortical pyramidal cells but fewer subcortical neurons, strongly reduced the cortical expression of parvalbumin (PV), indicating reduced activity of fast-spiking interneurons. Here, we used the well-studied rodent barrel cortex system to test how iTBS and continuous TBS (cTBS) modulate sensory responses evoked by either single or double stimuli applied to the principal (PW) and/or adjacent whisker (AW) in urethane-anaesthetized rats. Compared to sham stimulation, iTBS but not cTBS particularly enhanced late (>18 ms) response components of multi-unit spiking and local field potential responses in layer 4 but not the very early response (<18 ms). Similarly, only iTBS diminished the suppression of the second response evoked by paired PW or AW-PW stimulation at 20 ms intervals. The effects increased with each of the five iTBS blocks applied. With cTBS a mild effect similar to that of iTBS was first evident after 4-5 stimulation blocks. Enhanced cortical c-Fos and zif268 expression but reduced PV and GAD67 expression was found only after iTBS, indicating increased cortical activity due to lowered inhibition. We conclude that iTBS but less cTBS may primarily weaken a late recurrent-type cortical inhibition mediated via a subset of PV+ interneurons, enabling stronger late response components believed to contribute to the perception of sensory events. © 2014 The Authors. The Journal of Physiology © 2014 The Physiological Society.

Parallel-Connected Photovoltaic Inverters: Zero Frequency Sequence Harmonic Analysis and Solution

NASA Astrophysics Data System (ADS)

Carmeli, Maria Stefania; Mauri, Marco; Frosio, Luisa; Bezzolato, Alberto; Marchegiani, Gabriele

2013-05-01

High-power photovoltaic (PV) plants are usually constituted of the connection of different PV subfields, each of them with its interface transformer. Different solutions have been studied to improve the efficiency of the whole generation system. In particular, transformerless configurations are the more attractive one from efficiency and costs point of view. This paper focuses on transformerless PV configurations characterised by the parallel connection of interface inverters. The problem of zero sequence current due to both the parallel connection and the presence of undesirable parasitic earth capacitances is considered and a solution, which consists of the synchronisation of pulse-width modulation triangular carrier, is proposed and theoretically analysed. The theoretical analysis has been validated through simulation and experimental results.

Inner-ear sound pressures near the base of the cochlea in chinchilla: Further investigation

PubMed Central

Ravicz, Michael E.; Rosowski, John J.

2013-01-01

The middle-ear pressure gain GMEP, the ratio of sound pressure in the cochlear vestibule PV to sound pressure at the tympanic membrane PTM, is a descriptor of middle-ear sound transfer and the cochlear input for a given stimulus in the ear canal. GMEP and the cochlear partition differential pressure near the cochlear base ΔPCP, which determines the stimulus for cochlear partition motion and has been linked to hearing ability, were computed from simultaneous measurements of PV, PTM, and the sound pressure in scala tympani near the round window PST in chinchilla. GMEP magnitude was approximately 30 dB between 0.1 and 10 kHz and decreased sharply above 20 kHz, which is not consistent with an ideal transformer or a lossless transmission line. The GMEP phase was consistent with a roughly 50-μs delay between PV and PTM. GMEP was little affected by the inner-ear modifications necessary to measure PST. GMEP is a good predictor of ΔPCP at low and moderate frequencies where PV ⪢ PST but overestimates ΔPCP above a few kilohertz where PV ≈ PST. The ratio of PST to PV provides insight into the distribution of sound pressure within the cochlear scalae. PMID:23556590

Arsenic transformation and plant growth promotion characteristics of As-resistant endophytic bacteria from As-hyperaccumulator Pteris vittata.

PubMed

Xu, Jia-Yi; Han, Yong-He; Chen, Yanshan; Zhu, Ling-Jia; Ma, Lena Q

2016-02-01

The ability of As-resistant endophytic bacteria in As transformation and plant growth promotion was determined. The endophytes were isolated from As-hyperaccumulator Pteris vittata (PV) after growing for 60 d in a soil containing 200 mg kg(-1) arsenate (AsV). They were isolated in presence of 10 mM AsV from PV roots, stems, and leaflets, representing 4 phyla and 17 genera. All endophytes showed at least one plant growth promoting characteristics including IAA synthesis, siderophore production and P solubilization. The root endophytes had higher P solubilization ability than the leaflet (60.0 vs. 18.3 mg L(-1)). In presence of 10 mM AsV, 6 endophytes had greater growth than the control, suggesting As-stimulated growth. Furthermore, root endophytes were more resistant to AsV while the leaflet endophytes were more tolerant to arsenite (AsIII), which corresponded to the dominant As species in PV tissues. Bacterial As resistance was positively correlated to their ability in AsV reduction but not AsIII oxidation. The roles of those endophytes in promoting plant growth and As resistance in P. vittata warrant further investigation. Published by Elsevier Ltd.

High Performance Poly(viologen)-Graphene Nanocomposite Battery Materials with Puff Paste Architecture.

PubMed

Beladi-Mousavi, Seyyed Mohsen; Sadaf, Shamaila; Mahmood, Arsalan Mado; Walder, Lorenz

2017-09-26

Four linear poly(viologens) (PV1, PV2: phenylic, PV3: benzylic, and PV4: aliphatic) in tight molecular contact with reduced graphene oxide (rGO), that is, PV@rGO, were prepared and used as anodic battery materials. These composites show exceptionally high, areal, volumetric, and current densities, for example, PV1@rGO composites (with 15 wt % rGO, corresponding to 137 mAh g -1 ) show 13.3 mAh cm -2 at 460 μm and 288 mAh cm -3 with 98% Coulombic efficiency at current densities up to 1000 A g -1 , better than any reported organic materials. These remarkable performances are based on (i) molecular self-assembling of PVs on individual GO sheets yielding colloidal PV@GO and (ii) efficient GO/rGO transformation electrocatalyzed by PVs. Ion breathing during charging/discharging was studied by electrochemical quartz crystal microbalance and electrochemical atomic force microscopy revealing an absolute reversible and strongly anisotropic thickness oscillation of PV1@rGO at a right angle to the macroscopic current collector. It is proposed that such stress-free breathing is the key property for good cyclability of the battery material. The anisotropy is related to a puff paste architecture of rGO sheets parallel to the macroscopic current collector. A thin graphite sheet electrode with an areal capacity of 1.23 mAh cm -2 is stable over 200 bending cycles, making the material applicable for wearable electronics. The polymer acts as a lubricant between the rGO layers if shearing forces are active.

Modulation of inhibitory activity markers by intermittent theta-burst stimulation in rat cortex is NMDA-receptor dependent.

PubMed

Labedi, Adnan; Benali, Alia; Mix, Annika; Neubacher, Ute; Funke, Klaus

2014-01-01

Intermittent theta-burst stimulation (iTBS) applied via transcranial magnetic stimulation has been shown to increase cortical excitability in humans. In the rat brain it strongly reduced the number of neurons expressing the 67-kD isoform of the GABA-synthesizing enzyme glutamic acid decarboxylase (GAD67) and those expressing the calcium-binding proteins parvalbumin (PV) and calbindin (CB), specific markers of fast-spiking (FS) and non-FS inhibitory interneurons, respectively, an indication of modified cortical inhibition. Since iTBS effects in humans have been shown to be NMDA receptor sensitive, we wondered whether the iTBS-induced changes in the molecular phenotype of interneurons may be also sensitive to glutamatergic synaptic transmission mediated by NMDA receptors. In a sham-controlled fashion, five iTBS-blocks of 600 stimuli were applied to rats either lightly anesthetized by only urethane or by an additional low (subnarcotic) or high dose of the NMDA receptor antagonist ketamine before immunohistochemical analysis. iTBS reduced the number of neurons expressing GAD67, PV and CB. Except for CB, a low dose of ketamine partially prevented these effects while a higher dose almost completely abolished the iTBS effects. Our findings indicate that iTBS modulates the molecular, and likely also the electric, activity of cortical inhibitory interneurons and that the modulation of FS-type but less that of non-FS-type neurons is mediated by NMDA receptors. A combination of iTBS with pharmacological interventions affecting distinct receptor subtypes may thus offer options to enhance its selectivity in modulating the activity of distinct cell types and preventing others from being modulated. Copyright © 2014 Elsevier Inc. All rights reserved.

[Treatment with non-steroidal anti-inflammatory drugs in patients with amicrobial chronic prostato-vesiculitis: transrectal ultrasound and seminal findings].

PubMed

Vicari, E; La Vignera, S; Battiato, C; Arancio, A

2005-03-01

The aim of this paper was to evaluate the efficacy (0= none; 3= fully) of the treatment with nonsteroidal anti-inflammatory (NSAI) drugs on (a) gland post-inflammatory echopattern, by transrectal ultrasound (TRUS); (b) seminal cytologic (WBC concentration and spermiophagies) and (c) >2 physicochemical inflammatory parameters in patients with chronic amicrobial prostato-vesiculitis (PV). Thirty-five patients with PV received NSAI drugs in the following intermittently steps (over a 3-month period): 1) Pygeum 100 mg twice a day for 14 consecutive days per month; 2) flavoxate-propyphenazone 400 mg twice a day plus Serratiopeptidase 10 000 U twice a day for the subsequent 14 days per month. All patients underwent semen analysis and TRUS scans in the pre-treatment and after 3 months of therapy. The fully (a+b+c) efficacy rate, through an improvement of TRUS prostatic or vesicular echopattern in 37.1% and 22.8% respectively, was higher than that registered with an improvement of only 1 or 2 endpoints. Altogether, the following TRUS findings showed reductions (range 25-40%): prostate volume and hypochogenicity (51.4%); vesicular antero-posterior diameter (APD) in the 43.5% and 28.6% of the uni- and bilateral PV respectively; vesicular wall tickness (25%); unilateral vesicular honeycomb aspect (36%). No efficacy, mainly related to immodified TRUS prostatic or vesicular echopattern in 51.4% and 65.7% respectively, was observed on: areas of prostatic hyperechogenicity; peri-prostatic venous congestion; vesicular APD <7 mm or >21 mm (with honeycomb aspect). In PV patients, the treatment with NSAI compounds was effective when it was enable to produce multiple positive effects, mainly through TRUS changes.

VELOCITY FIELD OF COMPRESSIBLE MAGNETOHYDRODYNAMIC TURBULENCE: WAVELET DECOMPOSITION AND MODE SCALINGS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kowal, Grzegorz; Lazarian, A., E-mail: kowal@astro.wisc.ed, E-mail: lazarian@astro.wisc.ed

We study compressible magnetohydrodynamic turbulence, which holds the key to many astrophysical processes, including star formation and cosmic-ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid, we use wavelet decomposition of the turbulent velocity field into Alfven, slow, and fast modes, which presents an extension of the Cho and Lazarian decomposition approach based on Fourier transforms. The wavelets allow us to follow the variations of the local direction of the magnetic field and therefore improve the quality of the decomposition compared to the Fourier transforms, which are done in the mean field referencemore » frame. For each resulting component, we calculate the spectra and two-point statistics such as longitudinal and transverse structure functions as well as higher order intermittency statistics. In addition, we perform a Helmholtz- Hodge decomposition of the velocity field into incompressible and compressible parts and analyze these components. We find that the turbulence intermittency is different for different components, and we show that the intermittency statistics depend on whether the phenomenon was studied in the global reference frame related to the mean magnetic field or in the frame defined by the local magnetic field. The dependencies of the measures we obtained are different for different components of the velocity; for instance, we show that while the Alfven mode intermittency changes marginally with the Mach number, the intermittency of the fast mode is substantially affected by the change.« less

CHARACTERIZING INTERMITTENCY OF 4-Hz QUASI-PERIODIC OSCILLATION IN XTE J1550–564 USING HILBERT–HUANG TRANSFORM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Su, Yi-Hao; Chou, Yi; Hu, Chin-Ping

We present time-frequency analysis results based on the Hilbert–Huang transform (HHT) for the evolution of a 4-Hz low-frequency quasi-periodic oscillation (LFQPO) around the black hole X-ray binary XTE J1550–564. The origin of LFQPOs is still debated. To understand the cause of the peak broadening, we utilized a recently developed time-frequency analysis, HHT, for tracking the evolution of the 4-Hz LFQPO from XTE J1550–564. By adaptively decomposing the ∼4-Hz oscillatory component from the light curve and acquiring its instantaneous frequency, the Hilbert spectrum illustrates that the LFQPO is composed of a series of intermittent oscillations appearing occasionally between 3 and 5more » Hz. We further characterized this intermittency by computing the confidence limits of the instantaneous amplitudes of the intermittent oscillations, and constructed both the distributions of the QPO’s high- and low-amplitude durations, which are the time intervals with and without significant ∼4-Hz oscillations, respectively. The mean high-amplitude duration is 1.45 s and 90% of the oscillation segments have lifetimes below 3.1 s. The mean low-amplitude duration is 0.42 s and 90% of these segments are shorter than 0.73 s. In addition, these intermittent oscillations exhibit a correlation between the oscillation’s rms amplitude and mean count rate. This correlation could be analogous to the linear rms-flux relation found in the 4-Hz LFQPO through Fourier analysis. We conclude that the LFQPO peak in the power spectrum is broadened owing to intermittent oscillations with varying frequencies, which could be explained by using the Lense–Thirring precession model.« less

Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant.

PubMed

Moreno-Garcia, Isabel M; Palacios-Garcia, Emilio J; Pallares-Lopez, Victor; Santiago, Isabel; Gonzalez-Redondo, Miguel J; Varo-Martinez, Marta; Real-Calvo, Rafael J

2016-05-26

There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant's components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid.

Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

NASA Astrophysics Data System (ADS)

Seyf, Hamid Reza; Henry, Asegun

2017-01-01

We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

Analysis of a Concentrated Solar Thermophotovoltaic System with Thermal Energy Storage

NASA Astrophysics Data System (ADS)

Seyf, Hamid Reza; Henry, Asegun

We analyzed a high temperature concentrated solar thermophotovoltaic (TPV) system with thermal energy storage (TES), which is enabled by the potential usage of liquid metal as a high temperature heat transfer fluid. The system concept combines the great advantages of TES with the potential for low cost and high performance derived from photovoltaic cells fabricated on reusable substrates, with a high reflectivity back reflector for photon recycling. The TES makes the electricity produced dispatchable, and thus the system studied should be compared to technologies such as concentrated solar power (CSP) with TES (e.g., using a turbine) or PV with electrochemical batteries, instead of direct and intermittent electricity generation from flat plate PV alone. Thus, the addition of TES places the system in a different class than has previously been considered and based on the model results, appears worthy of increased attention. The system level analysis presented identifies important cell level parameters that have the greatest impact on the overall system performance, and as a result can help to set the priorities for future TPV cell development.

Evaluating the Cost-Benefits of Utilizing Host Nation Power for US Military Bases

DTIC Science & Technology

2016-01-29

treated.  In  fact, even the most unreliable host nation grids almost always have a higher availability then  solar   PV ,  which has at best a 30% capacity...fuel supply. In  this way, HN power is like other intermittent sources such as  solar  or wind power. HN power should not  be thought of as a

Experience with ruxolitinib in the treatment of polycythaemia vera

PubMed Central

Alimam, Samah; Harrison, Claire

2017-01-01

Polycythaemia vera (PV) is a myeloproliferative neoplasm classically characterized by an erythrocytosis and is associated with a high risk of thromboembolic events, constitutional symptoms burden and risk of transformation to myelofibrosis and acute myeloid leukaemia. Therapy is directed at the haematocrit (HCT) to reduce the risk of thrombotic events and usually comprises low-dose aspirin and phlebotomy to maintain HCT at >45%. Frequently in addition, cytoreductive therapy is indicated in high-risk patients for normalizing haematological parameters to mitigate the occurrence of thromboembolic events. Unfortunately, there is no clear evidence that current therapies reduce the risk of transformation to myelofibrosis and for some a risk of a therapy related complication is unknown for example leukaemia due to hydroxycarbamide (HC). First-line therapy for treating PV remains HC or interferon, the latter most often in younger patients, especially those of childbearing age. However, therapy related intolerance or resistance is a common feature and results in limited treatment options for such patients. The discovery of the JAK2 V617F mutation and consequently targeted therapy with Janus kinase inhibitors, in particular ruxolitinib, has extended the spectrum of agents that can be used as second or third line in PV. The findings of the phase II trial RESPONSE and the preliminary data from RESPONSE 2 trial have identified a role for ruxolitinib in PV patients who are resistant or intolerant to HC. In this article, using clinical cases we demonstrate our experience with ruxolitinib highlighting the clinical benefits and limitations we encountered in clinical practice. PMID:28491265

Kinetics of Ca2+ binding to parvalbumin in bovine chromaffin cells: implications for [Ca2+] transients of neuronal dendrites

PubMed Central

Lee, Suk-Ho; Schwaller, Beat; Neher, Erwin

2000-01-01

The effect of parvalbumin (PV) on [Ca2+] transients was investigated by perfusing adrenal chromaffin cells with fura-2 and fluorescein isothiocyanate (FITC)-labelled PV. As PV diffused into cells, the decay of [Ca2+] transients was transformed from monophasic into biphasic. The proportion of the initial fast decay phase increased in parallel with the fluorescence intensity of FITC, indicating that PV is responsible for the initial fast decay phase.The relationship between the fast decay phase and the [Ca2+] level was investigated using depolarizing trains of stimuli. Within a train the relative amplitude of the fast decay phase was inversely dependent on the [Ca2+] level preceding a given stimulus.Based on these observations, we estimated the Ca2+ binding ratio of PV (κP), the apparent dissociation constant of PV for Ca2+ (Kdc,app), and the unbinding rate constant of Ca2+ from PV (kc-) in the cytosol of chromaffin cells. Assuming free [Mg2+] to be 0.14 mm, we obtained values of 51.4 ± 2.0 nm (n = 3) and 0.95 ± 0.026 s−1 (n = 3), for Kdc,app and kc-, respectively.With the parameters obtained in the perfusion study, we simulated [Ca2+] transients, using two different Ca2+ extrusion rates (γ) – 20 and 300 s−1– which represent typical values for chromaffin cells and neuronal dendrites, respectively. The simulation indicated that Ca2+ is pumped out before it is equilibrated with PV, when γ is comparable to the equilibration rates between PV and Ca2+, resulting in the fast decay phase of a biexponential [Ca2+] transient.From these results we conclude that Ca2+ buffers with slow kinetics, such as PV, may cause biexponential decays in [Ca2+] transients, thereby complicating the analysis of endogenous Ca2+ binding ratios (κS) based on time constants. Nevertheless, estimates of κS based on Ca2+ increments provide reasonable estimates for Ca2+ binding ratios before equilibration with PV. PMID:10835044

DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krishnaswami, Hariharan

The DISTINCT project research objective is to develop an innovative N-port power converter for a utility-scale PV system that is modular, compact and cost-effective and that will enable the integration of a high-frequency, high-voltage solid-state transformer. The novelty of the proposed research is the electrical power conversion architecture using an N-port converter system that replaces the output 60Hz transformer with an integrated high-frequency low-weight solid-state transformer reducing power electronics and BOS costs to meet SunShot goals through modularity and direct high-voltage interconnection. A challenge in direct integration with a 13.8kV line is the high voltage handling capacity of the convertersmore » combined with high efficiency operation. The front-end converter for each port is a Neutral-Point Clamped (NPC) Multi-Level dc-dc Dual-Active Bridge (ML-DAB) which allows Maximum Power Point Tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is an inverter with H-bridge configuration or NPC configuration. N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e. 13.8 kV). The cascaded inverters have the inherent advantage of using lower rated devices, smaller filters and low Total Harmonic Distortion (THD) required for PV grid interconnection. Our analysis and simulation results show improved performance on cost, efficiency, service life with zero downtime and THD. A comprehensive control scheme is presented to ensure the maximum power from each port and each phase are sent to the grid. A functional prototype of a 2-port converter with ML-DAB and cascaded H-bridges has been designed, built, and tested in a laboratory setup to verify the target technical metrics. The N-port converter system due to its modular structure with individual control per port can be easily adapted to integrate functionalities that go well beyond the conventional grid support functions and mitigates impacts of forecasted fast ramp downs or ramp ups and single-fault conditions by automatic reconfiguration of the output.« less

Retargeting of Rat Parvovirus H-1PV to Cancer Cells through Genetic Engineering of the Viral Capsid

PubMed Central

Allaume, Xavier; El-Andaloussi, Nazim; Leuchs, Barbara; Bonifati, Serena; Kulkarni, Amit; Marttila, Tiina; Kaufmann, Johanna K.; Nettelbeck, Dirk M.; Kleinschmidt, Jürgen; Rommelaere, Jean

2012-01-01

The rat parvovirus H-1PV is a promising anticancer agent given its oncosuppressive properties and the absence of known side effects in humans. H-1PV replicates preferentially in transformed cells, but the virus can enter both normal and cancer cells. Uptake by normal cells sequesters a significant portion of the administered viral dose away from the tumor target. Hence, targeting H-1PV entry specifically to tumor cells is important to increase the efficacy of parvovirus-based treatments. In this study, we first found that sialic acid plays a key role in H-1PV entry. We then genetically engineered the H-1PV capsid to improve its affinity for human tumor cells. By analogy with the resolved crystal structure of the closely related parvovirus minute virus of mice, we developed an in silico three-dimensional (3D) model of the H-1PV wild-type capsid. Based on this model, we identified putative amino acids involved in cell membrane recognition and virus entry at the level of the 2-fold axis of symmetry of the capsid, within the so-called dimple region. In situ mutagenesis of these residues significantly reduced the binding and entry of H-1PV into permissive cells. We then engineered an entry-deficient viral capsid and inserted a cyclic RGD-4C peptide at the level of its 3-fold axis spike. This peptide binds αvβ3 and αvβ5 integrins, which are overexpressed in cancer cells and growing blood vessels. The insertion of the peptide rescued viral infectivity toward cells overexpressing αvβ5 integrins, resulting in the efficient killing of these cells by the reengineered virus. This work demonstrates that H-1PV can be genetically retargeted through the modification of its capsid, showing great promise for a more efficient use of this virus in cancer therapy. PMID:22258256

Retargeting of rat parvovirus H-1PV to cancer cells through genetic engineering of the viral capsid.

PubMed

Allaume, Xavier; El-Andaloussi, Nazim; Leuchs, Barbara; Bonifati, Serena; Kulkarni, Amit; Marttila, Tiina; Kaufmann, Johanna K; Nettelbeck, Dirk M; Kleinschmidt, Jürgen; Rommelaere, Jean; Marchini, Antonio

2012-04-01

The rat parvovirus H-1PV is a promising anticancer agent given its oncosuppressive properties and the absence of known side effects in humans. H-1PV replicates preferentially in transformed cells, but the virus can enter both normal and cancer cells. Uptake by normal cells sequesters a significant portion of the administered viral dose away from the tumor target. Hence, targeting H-1PV entry specifically to tumor cells is important to increase the efficacy of parvovirus-based treatments. In this study, we first found that sialic acid plays a key role in H-1PV entry. We then genetically engineered the H-1PV capsid to improve its affinity for human tumor cells. By analogy with the resolved crystal structure of the closely related parvovirus minute virus of mice, we developed an in silico three-dimensional (3D) model of the H-1PV wild-type capsid. Based on this model, we identified putative amino acids involved in cell membrane recognition and virus entry at the level of the 2-fold axis of symmetry of the capsid, within the so-called dimple region. In situ mutagenesis of these residues significantly reduced the binding and entry of H-1PV into permissive cells. We then engineered an entry-deficient viral capsid and inserted a cyclic RGD-4C peptide at the level of its 3-fold axis spike. This peptide binds α(v)β(3) and α(v)β(5) integrins, which are overexpressed in cancer cells and growing blood vessels. The insertion of the peptide rescued viral infectivity toward cells overexpressing α(v)β(5) integrins, resulting in the efficient killing of these cells by the reengineered virus. This work demonstrates that H-1PV can be genetically retargeted through the modification of its capsid, showing great promise for a more efficient use of this virus in cancer therapy.

Management of polycythaemia vera: a critical review of current data.

PubMed

McMullin, Mary F; Wilkins, Bridget S; Harrison, Claire N

2016-02-01

Polycythaemia vera (PV) is a chronic blood cancer; its clinical features are dominated by myeloproliferation (erythrocytosis, often leucocytosis and/or thrombocytosis) and a tendency for thrombosis and transformation to myelofibrosis or acute myeloid leukaemia. In the past 10 years the pathophysiology of this condition has been defined as JAK/STAT pathway activation, almost always due to mutations in JAK2 exons 12 or 14 (JAK2 V617F). In the same time period our understanding of the optimal management of PV has expanded, most recently culminating in the approval of JAK inhibitors for the treatment of PV patients who are resistant or intolerant to therapy with hydroxycarbamide. It has also been demonstrated that life expectancy for many patients with PV is not normal, nor is their quality of life. We critically explore these findings and discuss their impact. In addition, we highlight persisting gaps in our current management strategy; for example, what is the optimal first line cytoreductive therapy and, indeed, which patients need cytoreductive drugs. © 2015 John Wiley & Sons Ltd.

Real-Time Monitoring System for a Utility-Scale Photovoltaic Power Plant

PubMed Central

Moreno-Garcia, Isabel M.; Palacios-Garcia, Emilio J.; Pallares-Lopez, Victor; Santiago, Isabel; Gonzalez-Redondo, Miguel J.; Varo-Martinez, Marta; Real-Calvo, Rafael J.

2016-01-01

There is, at present, considerable interest in the storage and dispatchability of photovoltaic (PV) energy, together with the need to manage power flows in real-time. This paper presents a new system, PV-on time, which has been developed to supervise the operating mode of a Grid-Connected Utility-Scale PV Power Plant in order to ensure the reliability and continuity of its supply. This system presents an architecture of acquisition devices, including wireless sensors distributed around the plant, which measure the required information. It is also equipped with a high-precision protocol for synchronizing all data acquisition equipment, something that is necessary for correctly establishing relationships among events in the plant. Moreover, a system for monitoring and supervising all of the distributed devices, as well as for the real-time treatment of all the registered information, is presented. Performances were analyzed in a 400 kW transformation center belonging to a 6.1 MW Utility-Scale PV Power Plant. In addition to monitoring the performance of all of the PV plant’s components and detecting any failures or deviations in production, this system enables users to control the power quality of the signal injected and the influence of the installation on the distribution grid. PMID:27240365

Hybrid solar converters for maximum exergy and inexpensive dispatchable electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branz, Howard M.; Regan, William; Gerst, Kacy J.

Photovoltaic (PV) solar energy systems are being deployed at an accelerating rate to supply low-carbon electricity worldwide. However, PV is unlikely to economically supply much more than 10% of the world's electricity unless there is a dramatic reduction in the cost of electricity storage. There is an important scientific and technological opportunity to address the storage challenge by developing inexpensive hybrid solar converters that collect solar heat at temperatures between about 200 and 600 °C and also incorporate PV. Since heat can be stored and converted to electricity at relatively low cost, collection of high exergy content (high temperature) solarmore » heat can provide energy that is dispatchable on demand to meet loads that are not well matched to solar insolation. However, PV cells can collect and convert much of the solar spectrum to electricity more efficiently and inexpensively than solar thermal systems. Advances in spectrum-splitting optics, high-temperature PV cells, thermal management and system design are needed for transformational hybrid converters. We propose that maximizing the exergy output from the solar converters while minimizing the cost of exergy can help propel solar energy toward a higher contribution to carbon-free electricity in the long term than the prevailing paradigm of maximizing the energy output while minimizing the cost of energy« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rosenthal, A

Southwest Technology Development Institute (SWTDI), an independent, university-based research institute, has been the operator of the Southwest Region Photovoltaic Experiment Station (SWRES) for almost 30 years. The overarching mission of SWTDI is to position PV systems and solar technologies to become cost-effective, major sources of energy for the United States. Embedded in SWTDI's general mission has been the more-focused mission of the SWRES: to provide value added technical support to the DOE Solar Energy Technologies Program (SETP) to effectively and efficiently meet the R&D needs and targets specified in the SETP Multi-Year Technical Plan. : The DOE/SETP goals of growingmore » U.S. PV manufacturing into giga-watt capacities and seeing tera-watt-hours of solar energy production in the U.S. require an infrastructure that is under development. The staff of the SWRES has supported DOE/SETP through a coherent, integrated program to address infrastructural needs inhibiting wide-scale PV deployment in three major technical categories: specialized engineering services, workforce development, and deployment facilitation. The SWRES contract underwent three major revisions during its five year period-of- performance, but all tasks and deliverables fell within the following task areas: Task 1: PV Systems Assistance Center 1. Develop a Comprehensive multi-year plan 2. Provide technical workforce development materials and workshops for PV stakeholder groups including university, professional installers, inspectors, state energy offices, Federal agencies 3. Serve on the NABCEP exam committee 4. Provide on-demand technical PV system design reviews for U.S. PV stakeholders 5. Provide PV system field testing and instrumentation, technical outreach (including extensive support for the DOE Market Transformation program) Task 2: Design-for-Manufacture PV Systems 1. Develop and install 18 kW parking carport (cost share) and PV-thermal carport (Albuquerque) deriving and publishing lessons learned Task 3: PV Codes and Standards 1. Serve as the national lead for development and preparation of all proposals (related to PV) to the National Electrical Code 2. Participate in the Standards Technical Panels for modules (UL1703) and inverters (UL1741) Task 4: Assess Inverter Long Term Reliability 1. Install and monitor identical inverters at SWRES and SERES 2. Operate and monitor all inverters for 5 years, characterizing all failures and performance trends Task 5: Test and Evaluation Support for Solar America Initiative 1. Provide test and evaluation services to the National Laboratories for stage gate and progress measurements of SAI TPP winners« less

Geographic smoothing of solar PV: Results from Gujarat

DOE PAGES

Klima, Kelly; Apt, Jay

2015-09-24

We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log–log domain at high frequencies f,more » ranging from f -1.23 to f -1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f -1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f -1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.« less

Impact of heat treatments on the fatigue resistance of different rotary nickel-titanium instruments.

PubMed

Braga, Lígia Carolina Moreira; Faria Silva, Ana Cristina; Buono, Vicente Tadeu Lopes; de Azevedo Bahia, Maria Guiomar

2014-09-01

The aim of this study was to assess the influence of M-Wire (Dentsply Tulsa Dental Specialties, Tulsa, OK) and controlled memory technologies on the fatigue resistance of rotary nickel-titanium (NiTi) files by comparing files made using these 2 technologies with conventional NiTi files. Files with a similar cross-sectional design and diameter were chosen for the study: new 30/.06 files of the EndoWave (EW; J. Morita Corp, Osaka, Japan), HyFlex (HF; Coltene/Whaledent, Inc, Cuyahoga Falls, OH), ProFile Vortex (PV; Dentsply Tulsa Dental Specialties, Tulsa, OK), and Typhoon (TYP; Clinician's Choice Dental Products, New Milford, CT) systems together with ProTaper Universal F2 instruments (PTU F2; Dentsply Maillefer, Ballaigues, Switzerland). The compositions and transformation temperatures of the instruments were analyzed using x-ray energy-dispersive spectroscopy and differential scanning calorimetry, whereas the mean file diameter values at 3 mm from the tip (D3) were measured using image analysis software. The average number of cycles to failure was determined using a fatigue test device. X-ray energy-dispersive spectroscopy analysis showed that, on average, all the instruments exhibited the same chemical composition, namely, 51% Ni-49% Ti. The PV, TYP, and HF files exhibited increased transformation temperatures. The PTU F2, PV, and TYP files had similar D3 values, which were less than those of the EW and HF files. The average number of cycles to failure values were 150% higher for the TYP files compared with the PV files and 390% higher for the HF files compared with the EW files. M-Wire and controlled memory technologies increase the fatigue resistance of rotary NiTi files. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Dynamics of Mantle Plume Controlled by both Post-spinel and Post-garnet Phase Transitions

NASA Astrophysics Data System (ADS)

Liu, H.; Leng, W.

2017-12-01

Mineralogical studies indicate that two major phase transitions occur near 660 km depth in the Earth's pyrolitic mantle: the ringwoodite (Rw) to perovskite (Pv) + magnesiowüstite (Mw) and majorite (Mj) to perovskite (Pv) phase transitions. Seismological results also show a complicated phase boundary structure for plume regions at this depth, including broad pulse, double reflections and depressed 660 km discontinuity beneath hot regions etc… These observations have been attributed to the co-existence of these two phase transformations. However, previous geodynamical modeling mainly focused on the effects of Rw-Pv+Mw phase transition on the plume dynamics and largely neglected the effects of Mj-Pv phase transition. Here we develop a 3-D regional spherical geodynamic model to study the influence of the combination of Rw - Pv+Mw and Mj - Pv phase transitions on plume dynamics, including the topography fluctuation of 660 km discontinuity, plume shape and penetration capability of plume. Our results show that (1) a double phase boundary occurs at the hot center area of plume while for other regions with relatively lower temperature the phase boundary is single and flat, which respectively corresponds to the double reflections in the seismic observations and a high velocity prism-like structure at the top of 660 km discontinuity; (2) a large amount of low temperature plume materials could be trapped to form a complex trapezoid overlying the 660 km depth; (3) Mj - Pv phase change strongly enhances the plume penetration capability at 660 km depth, which significantly increases the plume mass flux due to the increased plume radius, but significantly reduces plume heat flux due to the decreased plume temperature in the upper mantle. Our model results provide new enlightenments for better constraining seismic structure and mineral reactions at 660 km phase boundaries.

Intermittency in electric brain activity in the perception of ambiguous images

NASA Astrophysics Data System (ADS)

Kurovskaya, Maria K.; Runnova, Anastasiya E.; Zhuravlev, Maxim O.; Grubov, Vadim V.; Koronovskii, Alexey A.; Pavlov, Alexey N.; Pisarchik, Alexander N.

2017-04-01

Present paper is devoted to the study of intermittency during the perception of bistable Necker cube image being a good example of an ambiguous object, with simultaneous measurement of EEG. Distributions of time interval lengths corresponding to the left-oriented and right-oriented cube perception have been obtain. EEG data have been analyzed using continuous wavelet transform and it was shown that the destruction of alpha rhythm with accompanying generation of high frequency oscillations can serve as a marker of Necker cube recognition process.

Validating the Operational Draft Regional Guidebook for the Functional Assessment of High-Gradient Ephemeral and Intermittent Headwater Streams in Western West Virginia and Eastern Kentucky

DTIC Science & Technology

2014-04-01

perennial streams than in intermittent streams (Feminella 1996 ; Fritz and Dodds 2005; Meyer and Meyer 2000; Pond et al. 2003; del Rosario and Resh 2000...Williams 1996 ; Wood et al. 2005; Wright et al. 1984). Lower invertebrate diversity and abundance estimates have been documented in headwater streams...transformations occurring through biogeochemical cycling (Benfield 1996 ; Aerts 1997). Organic carbon provides for maintenance of plant communities

Myeloid Blastic Transformation of Myeloproliferative Neoplasms – A Review of 112 Cases

PubMed Central

Noor, Syed J; Tan, Wei; Wilding, Gregory E; Ford, Laurie A; Barcos, Maurice; Sait, Sheila N J; Block, AnneMarie W; Thompson, James E; Wang, Eunice S; Wetzler, Meir

2010-01-01

Blastic transformation of myeloproliferative neoplasms (MPN) is still poorly understood. We describe a cohort of 23 Roswell Park Cancer Institute (RPCI) patients and 89 additional cases from the English literature for whom biologic features were described. We initially compared our 23 patients to the 89 cases from the literature. Our population had significantly less patients with prior history of polycythemia vera (PV), shorter time from MPN diagnosis to blastic transformation, <3 prior therapies, more frequent use of hydroxyurea and erythropoietin and less frequent use of alkylating agents. Interestingly, the overall survival of the two cohorts from the time of blastic transformation was similar. We therefore looked at the outcome of the entire cohort (n=112). Patients with prior history of essential thrombocythemia survived longer than patients with prior history of myelofibrosis or PV. Further, patients with <3 prior therapies, those who lacked complex karyotype and those <60 year old at MPN diagnosis had significantly longer survival. Among the PRCI population, 20/23 patients underwent induction treatment with cytarabine and an anthracycline containing regimens; 12 achieved remission and their overall survival was significantly longer than those who did not. Three patients underwent an allogeneic transplantation and their survival was significantly longer than those who did not. Patients with <3 prior therapies, those who lack complex karyotype and those <60 at MPN diagnosis have longer survival following blastic transformation. Finally, allogeneic transplantation represents the only chance for long-term survival in these patients. PMID:20727590

Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

PubMed

Mumtaz, Sidra; Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

2017-01-01

This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

Optimization and development of solar power system under diffused sunlight condition in rural areas with supercapacitor integration

NASA Astrophysics Data System (ADS)

Castelino, Roystan V.; Jana, Suman; Kumhar, Rajesh; Singh, Niraj K.

2018-04-01

The simulation and hardware based experiment in this presented paper shows a possibility of increasing the reliability of solar power under diffused condition by using super capacitor module. This experimental setup can be used in those areas where the sun light is intermittent and under the diffused radiation condition. Due to diffused radiation, solar PV cells operate very poorly, but by using this setup the power efficiency can be increased greatly. Sometimes dependent numerical models are used to measure the voltage and current response of the hardware setup in MATLAB Simulink based environment. To convert the scattered solar radiation to electricity using the conventional solar PV module, batteries have to be linked with the rapid charging or discharging device like super capacitor module. The conventional method consists of a charging circuit, which dumps the power if the voltage is below certain voltage level, but this circuit utilizes the entire power even if the voltage is low under diffused sun light conditions. There is no power dumped in this circuit. The efficiency and viability of this labscale experimental setup can be examined with further experiment and industrial model.

Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system

PubMed Central

Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

2017-01-01

This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms. PMID:28877191

Coordinated control of active and reactive power of distribution network with distributed PV cluster via model predictive control

NASA Astrophysics Data System (ADS)

Ji, Yu; Sheng, Wanxing; Jin, Wei; Wu, Ming; Liu, Haitao; Chen, Feng

2018-02-01

A coordinated optimal control method of active and reactive power of distribution network with distributed PV cluster based on model predictive control is proposed in this paper. The method divides the control process into long-time scale optimal control and short-time scale optimal control with multi-step optimization. The models are transformed into a second-order cone programming problem due to the non-convex and nonlinear of the optimal models which are hard to be solved. An improved IEEE 33-bus distribution network system is used to analyse the feasibility and the effectiveness of the proposed control method

Design and performance analysis of generalised integrator-based controller for grid connected PV system

NASA Astrophysics Data System (ADS)

Saxena, Hemant; Singh, Alka; Rai, J. N.

2018-07-01

This article discusses the design and control of a single-phase grid-connected photovoltaic (PV) system. A 5-kW PV system is designed and integrated at the DC link of an H-bridge voltage source converter (VSC). The control of the VSC and switching logic is modelled using a generalised integrator (GI). The use of GI or its variants such as second-order GI have recently evolved for synchronisation and are being used as phase locked loop (PLL) circuits for grid integration. Design of PLL circuits and the use of transformations such as Park's and Clarke's are much easier in three-phase systems. But obtaining in-phase and quadrature components becomes an important and challenging issue in single-phase systems. This article addresses this issue and discusses an altogether different application of GI for the design of compensator based on the extraction of in-phase and quadrature components. GI is frequently used as a PLL; however, in this article, it is not used for synchronisation purposes. A new controller has been designed for a single-phase grid-connected PV system working as a single-phase active compensator. Extensive simulation results are shown for the working of integrated PV system under different atmospheric and operating conditions during daytime as well as night conditions. Experimental results showing the proposed control approach are presented and discussed for the hardware set-up developed in the laboratory.

Evidence for exocellular Arsenic in Fronds of Pteris vittata

DOE PAGES

Datta, Rupali; Das, Padmini; Tappero, Ryan; ...

2017-06-06

The arsenic (As) hyperaccumulating fern species Pteris vittata (PV) is capable of accumulating large quantities of As in its aboveground tissues. Transformation to AsIII and vacuolar sequestration is believed to be the As detoxification mechanism in PV. Here we present evidence for a preponderance of exocellular As in fronds of Pteris vittata despite numerous reports of a tolerance mechanism involving intracellular compartmentalization. Results of an extraction experiment show that 43–71% of the As extruded out of the fronds of PV grown in 0.67, 3.3 and 6.7 mM AsV. SEM-EDX analysis showed that As was localized largely on the lower pinnamore » surface, with smaller amounts on the upper surface, as crystalline deposits. X-ray fluorescence imaging of pinna cross-sections revealed preferential localization of As on the pinna surface in the proximity of veins, with the majority localized near the midrib. Majority of the As in the pinnae is contained in the apoplast rather than vacuoles. Our results provide evidence that exocellular sequestration is potentially a mechanism of As detoxification in PV, particularly at higher As concentrations, raising concern about its use for phytoremediation.« less

Evidence for exocellular Arsenic in Fronds of Pteris vittata

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datta, Rupali; Das, Padmini; Tappero, Ryan

The arsenic (As) hyperaccumulating fern species Pteris vittata (PV) is capable of accumulating large quantities of As in its aboveground tissues. Transformation to AsIII and vacuolar sequestration is believed to be the As detoxification mechanism in PV. Here we present evidence for a preponderance of exocellular As in fronds of Pteris vittata despite numerous reports of a tolerance mechanism involving intracellular compartmentalization. Results of an extraction experiment show that 43–71% of the As extruded out of the fronds of PV grown in 0.67, 3.3 and 6.7 mM AsV. SEM-EDX analysis showed that As was localized largely on the lower pinnamore » surface, with smaller amounts on the upper surface, as crystalline deposits. X-ray fluorescence imaging of pinna cross-sections revealed preferential localization of As on the pinna surface in the proximity of veins, with the majority localized near the midrib. Majority of the As in the pinnae is contained in the apoplast rather than vacuoles. Our results provide evidence that exocellular sequestration is potentially a mechanism of As detoxification in PV, particularly at higher As concentrations, raising concern about its use for phytoremediation.« less

Continuous and intermittent transcranial magnetic theta burst stimulation modify tactile learning performance and cortical protein expression in the rat differently.

PubMed

Mix, Annika; Benali, Alia; Eysel, Ulf T; Funke, Klaus

2010-11-01

Repetitive transcranial magnetic stimulation (rTMS) can modulate cortical excitability in a stimulus-frequency-dependent manner. Two kinds of theta burst stimulation (TBS) [intermittent TBS (iTBS) and continuous TBS (cTBS)] modulate human cortical excitability differently, with iTBS increasing it and cTBS decreasing it. In rats, we recently showed that this is accompanied by changes in the cortical expression of proteins related to the activity of inhibitory neurons. Expression levels of the calcium-binding protein parvalbumin (PV) and of the 67-kDa isoform of glutamic acid decarboxylase (GAD67) were strongly reduced following iTBS, but not cTBS, whereas both increased expression of the 65-kDa isoform of glutamic acid decarboxylase. In the present study, to investigate possible functional consequences, we applied iTBS and cTBS to rats learning a tactile discrimination task. Conscious rats received either verum or sham rTMS prior to the task. Finally, to investigate how rTMS and learning effects interact, protein expression was determined for cortical areas directly involved in the task and for those either not, or indirectly, involved. We found that iTBS, but not cTBS, improved learning and strongly reduced cortical PV and GAD67 expression. However, the combination of learning and iTBS prevented this effect in those cortical areas involved in the task, but not in unrelated areas. We conclude that the improved learning found following iTBS is a result of the interaction of two effects, possibly in a homeostatic manner: a general weakening of inhibition mediated by the fast-spiking interneurons, and re-established activity in those neurons specifically involved in the learning task, leading to enhanced contrast between learning-induced and background activity. © 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Transformation of taxol-producing endophytic fungi by restriction enzyme-mediated integration (REMI).

PubMed

Wang, Yechun; Guo, Binhui; Miao, Zhiqi; Tang, Kexuan

2007-08-01

The REMI method was used to introduce the plasmid pV2 harboring the hygromycin B phosphotransferase (hph) gene controlled by the Aspergillus nidulans trpC promoter and the trpC terminator into a taxol-producing endophytic fungus BT2. REMI transformation yielded stable transformants capable of continuing to grow on PDA medium containing 125 mug mL(-1) hygromycin B. The transformation efficiency was about 5-6 transformants mug(-1) plasmid DNA. The presence of hph gene in transformants was confirmed by PCR and Southern blot analyses. To the authors' knowledge, this is the first report on the transformation of taxol-producing endophytic fungi by the REMI technique. This study provides an effective approach for improving taxol production of endophytic fungi by the genetic engineering of taxol biosynthetic pathway genes in the future.

Grid tied PV/battery system architecture and power management for fast electric vehicle charging

NASA Astrophysics Data System (ADS)

Badawy, Mohamed O.

The prospective spread of Electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) arises the need for fast charging rates. Higher charging rates requirements lead to high power demands, which cant be always supported by the grid. Thus, the use of on-site sources alongside the electrical grid for EVs charging is a rising area of interest. In this dissertation, a photovoltaic (PV) source is used to support the high power EVs charging. However, the PV output power has an intermittent nature that is dependable on the weather conditions. Thus, battery storage are combined with the PV in a grid tied system, providing a steady source for on-site EVs use in a renewable energy based fast charging station. Verily, renewable energy based fast charging stations should be cost effective, efficient, and reliable to increase the penetration of EVs in the automotive market. Thus, this Dissertation proposes a novel power flow management topology that aims on decreasing the running cost along with innovative hardware solutions and control structures for the developed architecture. The developed power flow management topology operates the hybrid system at the minimum operating cost while extending the battery lifetime. An optimization problem is formulated and two stages of optimization, i.e online and offline stages, are adopted to optimize the batteries state of charge (SOC) scheduling and continuously compensate for the forecasting errors. The proposed power flow management topology is validated and tested with two metering systems, i.e unified and dual metering systems. The results suggested that minimal power flow is anticipated from the battery storage to the grid in the dual metering system. Thus, the power electronic interfacing system is designed accordingly. Interconnecting bi-directional DC/DC converters are analyzed, and a cascaded buck boost (CBB) converter is chosen and tested under 80 kW power flow rates. The need to perform power factor correction (PFC) on the grid power while supplying the battery storage and the DC loads inspired a novel dual switch control structure for the CBB AC/DC converter used in this dissertation. Thus, The CBB operates at a discontinuous capacitor voltage mode (DCVM) and the control structure enables for a non-distorted input current at overlapping output voltage levels. The PFC concept is validated and tested for a single phase rectifier and a 3 phase extension of the proposed concept is presented. Lastly, the PV source used in this study is required to supply power to both, the grid system, and to the DC loads, i.e the battery storage and the EVs. Thus, the PV panels used are connected in series to reach a desirable high voltage on the DC bus output of the PV system. Consequently, a novel differential power processing architecture is proposed in this dissertation. The proposed architecture enables each PV element to operate at its local maximum power point (MPP) while processing only a small portion of its total generated power through the distributed integrated converters. This leads to higher energy capture at an increased conversion efficiency while overcoming the difficulties associated with unmatched MPPs of the PV elements.

Intermittent fasting modulates IgA levels in the small intestine under intense stress: a mouse model.

PubMed

Lara-Padilla, Eleazar; Godínez-Victoria, Marycarmen; Drago-Serrano, Maria Elisa; Reyna-Garfias, Humberto; Arciniega-Martínez, Ivonne Maciel; Abarca-Rojano, Edgar; Cruz-Hernández, Teresita Rocío; Campos-Rodríguez, Rafael

2015-08-15

Intermittent fasting prolongs the lifespan and unlike intense stress provides health benefits. Given the role of the immunoglobulin A (IgA) in the intestinal homeostasis, the aim of this study was to assess the impact of intermittent fasting plus intense stress on secretory IgA (SIgA) production and other mucosal parameters in the duodenum and ileum. Two groups of six mice, with intermittent fasting or fed ad libitum for 12weeks, were submitted to a session of intense stress by a bout of forced swimming. Unstressed ad libitum fed or intermittently fasted groups were included as controls. After sacrifice, we evaluated intestinal SIgA and plasma adrenal hormones, lamina propria IgA+ plasma-cells, mRNA expression of polymeric immunoglobulin receptor, α- and J-chains in the liver and intestinal mucosa, as well as pro- (tumor necrosis factor-α, interleukin-6 and Interferon-γ) and anti- (interleukin-2, -4, -10 and transforming growth factor-β) inflammatory cytokines in mucosal samples. Under intense stress, intermittent fasting down- or up-modulated the levels of most parameters in the duodenum and ileum, respectively while up-regulated corticosterone levels without affecting epinephrine. Our data suggest intermittent fasting plus intense stress elicited neuroendocrine pathways that differentially controlled IgA and pIgR expression in duodenum and ileum. These findings provide experimental foundations for a presumable impact of intermittent fasting under intense stress on the intestinal homeostasis or inflammation by triggering or reducing the IgA production in ileum or duodenum respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

How to Integrate Variable Power Source into a Power Grid

NASA Astrophysics Data System (ADS)

Asano, Hiroshi

This paper discusses how to integrate variable power source such as wind power and photovoltaic generation into a power grid. The intermittent renewable generation is expected to penetrate for less carbon intensive power supply system, but it causes voltage control problem in the distribution system, and supply-demand imbalance problem in a whole power system. Cooperative control of customers' energy storage equipment such as water heater with storage tank for reducing inverse power flow from the roof-top PV system, the operation technique using a battery system and the solar radiation forecast for stabilizing output of variable generation, smart charging of plug-in hybrid electric vehicles for load frequency control (LFC), and other methods to integrate variable power source with improving social benefits are surveyed.

Functional specialization of one copy of glutamine phosphoribosyl pyrophosphate amidotransferase in ureide production from symbiotically fixed nitrogen in Phaseolus vulgaris.

PubMed

Coleto, Inmaculada; Trenas, Almudena T; Erban, Alexander; Kopka, Joachim; Pineda, Manuel; Alamillo, Josefa M

2016-08-01

Purines are essential molecules formed in a highly regulated pathway in all organisms. In tropical legumes, the nitrogen fixed in the nodules is used to generate ureides through the oxidation of de novo synthesized purines. Glutamine phosphoribosyl pyrophosphate amidotransferase (PRAT) catalyses the first committed step of de novo purine synthesis. In Phaseolus vulgaris there are three genes coding for PRAT. The three full-length sequences, which are intron-less genes, were cloned, and their expression levels were determined under conditions that affect the synthesis of purines. One of the three genes, PvPRAT3, is highly expressed in nodules and protein amount and enzymatic activity in these tissues correlate with nitrogen fixation activity. Inhibition of PvPRAT3 gene expression by RNAi-silencing and subsequent metabolomic analysis of the transformed roots shows that PvPRAT3 is essential for the synthesis of ureides in P. vulgaris nodules. © 2016 John Wiley & Sons Ltd.

Defining the Thrombotic Risk in Patients with Myeloproliferative Neoplasms

PubMed Central

Vianello, Fabrizio; Battisti, Anna; Cella, Giuseppe; Marchetti, Marina; Falanga, Anna

2011-01-01

Polycythemia vera (PV) and essential thrombocythemia (ET) are two Philadelphia-negative myeloproliferative neoplasms (MPN) associated with an acquired mutation in the JAK2 tyrosine kinase gene. There is a rare incidence of progression to myelofibrosis and myeloid metaplasia in both disorders, which may or may not precede transformation to acute myeloid leukemia, but thrombosis is the main cause of morbidity and mortality. The pathophysiology of thrombosis in patients with MPN is complex. Traditionally, abnormalities of platelet number and function have been claimed as the main players, but increased dynamic interactions between platelets, leukocytes, and the endothelium do probably represent a fundamental interplay in generating a thrombophilic state. In addition, endothelial dysfunction, a well-known risk factor for vascular disease, may play a role in the thrombotic risk of patients with PV and ET. The identification of plasma markers translating the hemostatic imbalance in patients with PV and ET would be extremely helpful in order to define the subgroup of patients with a significant clinical risk of thrombosis. PMID:21623459

Vascular uptake of rehydration fluids in hypohydrated men at rest and exercise

NASA Technical Reports Server (NTRS)

Greenleaf, J. E.; Geelen, G.; Jackson, C. G. R.; Saumet, J.-L.; Juhos, L. T.; Keil, L. C.; Fegan-Meyer, D.; Dearborn, A.; Hinghofer-Szalkay, H.; Whittam, J. H.

1992-01-01

The purpose of this study was to formulate and to evaluate rehydration drinks, which would restore total body water and plasma volume (PV), for astronauts to consume before and during extravehicular activity, a few hours before reentry, and immediately after landing. In the first experiment (rest, sitting), five healthy men (23-41 yr), previously dehydrated for 24 hr., drank six (1a, 2, 4, 5, 6, 7) fluid formulations (one each at weekly intervals) and then sat for 70 min. Pre-test PV were measured with Evans blue dye and changes in PV were calculated with the hematocrit-hemoglobin transformation equation. This rest experiment simulated hypohydrated astronauts preparing for reentry. The second experiment (exercise, supine) followed the same protocol except four healthy men (30-46 yr) worked for 70 min. in the supine position on a cycle ergometer at a mean load of 71+/-1 percent of their peak aerobic work capacity. This exercise experiment simulated conditions for astronauts with reduced total body water engaging in extravehicular activity.

Betapapillomaviruses: innocent bystanders or causes of skin cancer.

PubMed

Feltkamp, Mariet C W; de Koning, Maurits N C; Bavinck, Jan Nico Bouwes; Ter Schegget, Jan

2008-12-01

Human papillomaviruses (HPV) are found in almost all squamous epithelia where they can cause hyperproliferative disease of mucosa and skin. Mucosal HPV types, such as HPV6 and HPV16, are known to cause anogenital warts and dysplasia or neoplasia, respectively. These HPV types have been studied extensively, and for some of them recently preventive vaccines have become available. Although HPV that populate the skin were the first identified HPV types, knowledge of the pathogenicity of HPV in the cornified epithelia stayed behind. What the majority of cutaneous HPV types do, for instance those belonging to the beta genus (betaPV), is largely unknown. As the number of reports that describe epidemiological associations between markers of betaPV infection and skin cancer gradually increases, the need for basic knowledge about these viruses grows as well. This review aims to picture what is currently known about betaPV with respect to infection, transmission and transformation, in order to envisage their potential role in cutaneous carcinogenesis.

Electronic Equipment Proposal to Improve the Photovoltaic Systems Efficiency

NASA Astrophysics Data System (ADS)

Flores-Mena, J. E.; Juárez Morán, L. A.; Díaz Reyes, J.

2011-05-01

This paper reports a new technique proposal to improve the photovoltaic systems. It was made to design and implement an electronic system that will detect, capture, and transfer the maximum power of the photovoltaic (PV) panel to optimize the supplied power of a solar panel. The electronic system works on base technical proposal of electrical sweeping of electric characteristics using capacitive impedance. The maximum power is transformed and the solar panel energy is sent to an automotive battery. This electronic system reduces the energy lost originated when the solar radiation level decreases or the PV panel temperature is increased. This electronic system tracks, captures, and stores the PV module's maximum power into a capacitor. After, a higher voltage level step-up circuit was designed to increase the voltage of the PV module's maximum power and then its current can be sent to a battery. The experimental results show that the developed electronic system has 95% efficiency. The measurement was made to 50 W, the electronic system works rightly with solar radiation rate from 100 to 1,000 W m - 2 and the PV panel temperature rate changed from 1 to 75°C. The main advantage of this electronic system compared with conventional methods is the elimination of microprocessors, computers, and sophisticated numerical approximations, and it does not need any small electrical signals to track the maximum power. The proposed method is simple, fast, and it is also cheaper.

A study on thermal characteristics analysis model of high frequency switching transformer

NASA Astrophysics Data System (ADS)

Yoo, Jin-Hyung; Jung, Tae-Uk

2015-05-01

Recently, interest has been shown in research on the module-integrated converter (MIC) in small-scale photovoltaic (PV) generation. In an MIC, the voltage boosting high frequency transformer should be designed to be compact in size and have high efficiency. In response to the need to satisfy these requirements, this paper presents a coupled electromagnetic analysis model of a transformer connected with a high frequency switching DC-DC converter circuit while considering thermal characteristics due to the copper and core losses. A design optimization procedure for high efficiency is also presented using this design analysis method, and it is verified by the experimental result.

Mixing rates and limit theorems for random intermittent maps

NASA Astrophysics Data System (ADS)

Bahsoun, Wael; Bose, Christopher

2016-04-01

We study random transformations built from intermittent maps on the unit interval that share a common neutral fixed point. We focus mainly on random selections of Pomeu-Manneville-type maps {{T}α} using the full parameter range 0<α <∞ , in general. We derive a number of results around a common theme that illustrates in detail how the constituent map that is fastest mixing (i.e. smallest α) combined with details of the randomizing process, determines the asymptotic properties of the random transformation. Our key result (theorem 1.1) establishes sharp estimates on the position of return time intervals for the quenched dynamics. The main applications of this estimate are to limit laws (in particular, CLT and stable laws, depending on the parameters chosen in the range 0<α <1 ) for the associated skew product; these are detailed in theorem 3.2. Since our estimates in theorem 1.1 also hold for 1≤slant α <∞ we study a second class of random transformations derived from piecewise affine Gaspard-Wang maps, prove existence of an infinite (σ-finite) invariant measure and study the corresponding correlation asymptotics. To the best of our knowledge, this latter kind of result is completely new in the setting of random transformations.

Solar Photovoltaic (PV) Distributed Generation Systems - Control and Protection

NASA Astrophysics Data System (ADS)

Yi, Zhehan

This dissertation proposes a comprehensive control, power management, and fault detection strategy for solar photovoltaic (PV) distribution generations. Battery storages are typically employed in PV systems to mitigate the power fluctuation caused by unstable solar irradiance. With AC and DC loads, a PV-battery system can be treated as a hybrid microgrid which contains both DC and AC power resources and buses. In this thesis, a control power and management system (CAPMS) for PV-battery hybrid microgrid is proposed, which provides 1) the DC and AC bus voltage and AC frequency regulating scheme and controllers designed to track set points; 2) a power flow management strategy in the hybrid microgrid to achieve system generation and demand balance in both grid-connected and islanded modes; 3) smooth transition control during grid reconnection by frequency and phase synchronization control between the main grid and microgrid. Due to the increasing demands for PV power, scales of PV systems are getting larger and fault detection in PV arrays becomes challenging. High-impedance faults, low-mismatch faults, and faults occurred in low irradiance conditions tend to be hidden due to low fault currents, particularly, when a PV maximum power point tracking (MPPT) algorithm is in-service. If remain undetected, these faults can considerably lower the output energy of solar systems, damage the panels, and potentially cause fire hazards. In this dissertation, fault detection challenges in PV arrays are analyzed in depth, considering the crossing relations among the characteristics of PV, interactions with MPPT algorithms, and the nature of solar irradiance. Two fault detection schemes are then designed as attempts to address these technical issues, which detect faults inside PV arrays accurately even under challenging circumstances, e.g., faults in low irradiance conditions or high-impedance faults. Taking advantage of multi-resolution signal decomposition (MSD), a powerful signal processing technique based on discrete wavelet transformation (DWT), the first attempt is devised, which extracts the features of both line-to-line (L-L) and line-to-ground (L-G) faults and employs a fuzzy inference system (FIS) for the decision-making stage of fault detection. This scheme is then improved as the second attempt by further studying the system's behaviors during L-L faults, extracting more efficient fault features, and devising a more advanced decision-making stage: the two-stage support vector machine (SVM). For the first time, the two-stage SVM method is proposed in this dissertation to detect L-L faults in PV system with satisfactory accuracies. Numerous simulation and experimental case studies are carried out to verify the proposed control and protection strategies. Simulation environment is set up using the PSCAD/EMTDC and Matlab/Simulink software packages. Experimental case studies are conducted in a PV-battery hybrid microgrid using the dSPACE real-time controller to demonstrate the ease of hardware implementation and the controller performance. Another small-scale grid-connected PV system is set up to verify both fault detection algorithms which demonstrate promising performances and fault detecting accuracies.

Why do team-sport athletes drink fluid in excess when exercising in cool conditions?

PubMed

Bargh, Melissa J; King, Roderick F G J; Gray, Michael P; Jones, Ben

2017-03-01

This study assessed the potential physiological and perceptual drivers of fluid intake and thirst sensation during intermittent exercise. Ten male rugby players (17 ± 1 years, stature: 179.1 ± 4.2 cm, body mass (BM): 81.9 ± 8.1 kg) participated in six 6-min small-sided games, interspersed with 2 min rest, where fluid intake was ad libitum during rest periods. Pre- and postmeasurements of BM, subjective ratings (thirst, thermal comfort, thermal sensation, mouth dryness), plasma osmolality (POsm), serum sodium concentration (S[Na + ]), haematocrit and haemoglobin (to calculate plasma volume change; PV) were taken. Fluid intake was measured during rest periods. BM change was -0.17 ± 0.59% and fluid intake was 0.88 ± 0.38 L. Pre- to post-POsm decreased (-3.1 ± 2.3 mOsm·kg -1 ; p = 0.002) and S[Na + ] remained similar (-0.3 ± 0.7 mmol·L -1 , p = 0.193). ΔPV was 5.84 ± 3.65%. Fluid intake displayed a relationship with pre-POsm (r = -0.640, p = 0.046), prethermal comfort (r = 0.651; p = -0.041), ΔS[Na + ] (r = 0.816, p = 0.004), and ΔPV (r = 0.740; p = 0.014). ΔThirst sensation displayed a relationship with premouth dryness (r = 0.861, p = 0.006) and Δmouth dryness (r = 0.878, p = 0.004). Yet a weak positive relationship between Δthirst sensation and fluid intake was observed (r = 0.085, p = 0.841). These data observed in an ambient temperature of 13.6 ± 0.9 °C, suggest team-sport athletes drink in excess of fluid homeostasis requirements and thirst sensation in cool conditions; however, this was not influenced by thermal discomfort.

Effects of pomegranate extract on blood flow and running time to exhaustion.

PubMed

Trexler, Eric T; Smith-Ryan, Abbie E; Melvin, Malia N; Roelofs, Erica J; Wingfield, Hailee L

2014-09-01

Recent research has shown that dietary nitrate has favorable effects on blood flow and exercise performance. The purpose of this randomized, double-blind, placebo-controlled crossover study was to investigate the acute effects of pomegranate extract on blood flow, vessel diameter, and exercise performance in active individuals. Nineteen men and women (mean ± SD: age, 22.2 ± 2.2 years; height, 174.8 ± 10.7 cm; body mass, 71.9 ± 13.5 kg) were randomly assigned to a placebo (PL) or pomegranate extract (PE) group. Participants performed a maximal oxygen consumption treadmill test to determine peak velocity (PV). Participants returned after 24-48 h and ingested either PL or PE. Brachial artery blood flow was assessed using ultrasound at baseline and 30 min post-ingestion (30minPI). Three treadmill runs to exhaustion were performed at 90%, 100%, and 110% PV. Blood flow was assessed immediately after each exercise bout and 30 min postexercise (30minPEx). After a 7-10 day washout, participants repeated the same procedures, ingesting the opposite supplement. Separate repeated measures ANOVAs were performed for blood flow, vessel diameter, and time to exhaustion (TTE). Blood flow was significantly augmented (p = 0.033) 30minPI with PE in comparison with PL. Vessel diameter was significantly larger (p = 0.036) 30minPEx with PE. Ingestion of PE was found to significantly augment TTE at 90% (p = 0.009) and 100% PV (p = 0.027). Acute ingestion of PE 30 min before exercise may enhance vessel diameter and blood flow and delay fatigue during exercise. Results of the current study indicate that PE is ergogenic for intermittent running, eliciting beneficial effects on blood flow.

Adaptive control paradigm for photovoltaic and solid oxide fuel cell in a grid-integrated hybrid renewable energy system.

PubMed

Mumtaz, Sidra; Khan, Laiq

2017-01-01

The hybrid power system (HPS) is an emerging power generation scheme due to the plentiful availability of renewable energy sources. Renewable energy sources are characterized as highly intermittent in nature due to meteorological conditions, while the domestic load also behaves in a quite uncertain manner. In this scenario, to maintain the balance between generation and load, the development of an intelligent and adaptive control algorithm has preoccupied power engineers and researchers. This paper proposes a Hermite wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control of photovoltaic (PV) systems to extract maximum power and a Hermite wavelet incorporated NeuroFuzzy indirect adaptive control of Solid Oxide Fuel Cells (SOFC) to obtain a swift response in a grid-connected hybrid power system. A comprehensive simulation testbed for a grid-connected hybrid power system (wind turbine, PV cells, SOFC, electrolyzer, battery storage system, supercapacitor (SC), micro-turbine (MT) and domestic load) is developed in Matlab/Simulink. The robustness and superiority of the proposed indirect adaptive control paradigm are evaluated through simulation results in a grid-connected hybrid power system testbed by comparison with a conventional PI (proportional and integral) control system. The simulation results verify the effectiveness of the proposed control paradigm.

Adaptive control paradigm for photovoltaic and solid oxide fuel cell in a grid-integrated hybrid renewable energy system

PubMed Central

Khan, Laiq

2017-01-01

The hybrid power system (HPS) is an emerging power generation scheme due to the plentiful availability of renewable energy sources. Renewable energy sources are characterized as highly intermittent in nature due to meteorological conditions, while the domestic load also behaves in a quite uncertain manner. In this scenario, to maintain the balance between generation and load, the development of an intelligent and adaptive control algorithm has preoccupied power engineers and researchers. This paper proposes a Hermite wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control of photovoltaic (PV) systems to extract maximum power and a Hermite wavelet incorporated NeuroFuzzy indirect adaptive control of Solid Oxide Fuel Cells (SOFC) to obtain a swift response in a grid-connected hybrid power system. A comprehensive simulation testbed for a grid-connected hybrid power system (wind turbine, PV cells, SOFC, electrolyzer, battery storage system, supercapacitor (SC), micro-turbine (MT) and domestic load) is developed in Matlab/Simulink. The robustness and superiority of the proposed indirect adaptive control paradigm are evaluated through simulation results in a grid-connected hybrid power system testbed by comparison with a conventional PI (proportional and integral) control system. The simulation results verify the effectiveness of the proposed control paradigm. PMID:28329015

After 10years of JAK2V617F: Disease biology and current management strategies in polycythaemia vera.

PubMed

Grinfeld, Jacob; Godfrey, Anna L

2017-05-01

The JAK2V617F mutation accounts for the vast majority of patients with polycythaemia vera (PV) and around half of those with other Philadelphia-negative myeloproliferative neoplasms. Since its discovery in 2005, numerous insights have been gained into the pathways by which JAK2V617F causes myeloproliferation, including activation of JAK-STAT signalling but also through other canonical and non-canonical pathways. A variety of mechanisms explain how this one mutation can be associated with distinct clinical disorders, demonstrating how constitutional and acquired factors may interact in the presence of a single mutation to determine disease phenotype. Important biological questions remain unanswered in PV, in particular how JAK2V617F affects stem cell function and what mechanisms drive myelofibrotic and leukaemic transformation. Whilst current management is largely centred on prevention of cardiovascular events, future therapies must aim to target the JAK2-mutant clone, to reverse the underlying marrow pathology and to address the risk of transformation events. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intermittent behavior in the brain neuronal network in the perception of ambiguous images

NASA Astrophysics Data System (ADS)

Hramov, Alexander E.; Kurovskaya, Maria K.; Runnova, Anastasiya E.; Zhuravlev, Maxim O.; Grubov, Vadim V.; Koronovskii, Alexey A.; Pavlov, Alexey N.; Pisarchik, Alexander N.

2017-03-01

Characteristics of intermittency during the perception of ambiguous images have been studied in the case the Necker cube image has been used as a bistable object for demonstration in the experiments, with EEG being simultaneously measured. Distributions of time interval lengths corresponding to the left-oriented and right-oriented Necker cube perception have been obtain. EEG data have been analyzed using continuous wavelet transform which was shown that the destruction of alpha rhythm with accompanying generation of high frequency oscillations can serve as a electroencephalographical marker of Necker cube recognition process in human brain.

Evolutionary and structural analyses of alpha-papillomavirus capsid proteins yields novel insights into L2 structure and interaction with L1

PubMed Central

Lowe, John; Panda, Debasis; Rose, Suzanne; Jensen, Ty; Hughes, Willie A; Tso, For Yue; Angeletti, Peter C

2008-01-01

Background PVs (PV) are small, non-enveloped, double-stranded DNA viruses that have been identified as the primary etiological agent for cervical cancer and their potential for malignant transformation in mucosal tissue has a large impact on public health. The PV family Papillomaviridae is organized into multiple genus based on sequential parsimony, host range, tissue tropism, and histology. We focused this analysis on the late gene products, major (L1) and minor (L2) capsid proteins from the family Papillomaviridae genus Alpha-papillomavirus. Alpha-PVs preferentially infect oral and anogenital mucosa of humans and primates with varied risk of oncogenic transformation. Development of evolutionary associations between PVs will likely provide novel information to assist in clarifying the currently elusive relationship between PV and its microenvironment (i.e., the single infected cell) and macro environment (i.e., the skin tissue). We attempt to identify the regions of the major capsid proteins as well as minor capsid proteins of alpha-papillomavirus that have been evolutionarily conserved, and define regions that are under constant selective pressure with respect to the entire family of viruses. Results This analysis shows the loops of L1 are in fact the most variable regions among the alpha-PVs. We also identify regions of L2, involved in interaction with L1, as evolutionarily conserved among the members of alpha- PVs. Finally, a predicted three-dimensional model was generated to further elucidate probable aspects of the L1 and L2 interaction. PMID:19087355

Risk of second primary malignancies and survival of adult patients with polycythemia vera: A United States population-based retrospective study.

PubMed

Khanal, Nabin; Giri, Smith; Upadhyay, Smrity; Shostrom, Valerie K; Pathak, Ranjan; Bhatt, Vijaya Raj

2016-01-01

Although the median survival in polycythemia vera (PV) is 14 years, mortality is higher than in an age- and sex-matched population. This study included 3941 PV patients diagnosed between 2000-2012 from Surveillance, Epidemiology and End Results (SEER) 13 registry to determine 5-year survival and the incidence of second primary malignancies (SPM). The actuarial 5 year survival in the overall cohort was 79.5%. The cumulative incidence of SPM was 13.1% at 10 years. SPMs occurred at a standardized incidence ratio (SIR) of 1.29 (95% CI = 1.16-1.43; p < 0.001) with an absolute excess risk (AER) of 42.49 per 10 000 population. A significantly higher risk was noted for acute myeloid leukemia (SIR = 12.24; 95% CI = 8.17-17.8; p-value < 0.001) and chronic myeloid leukemia (SIR = 10.66; 95% CI = 3.75-19.6; p-value < 0.001). Patients with PV are at a high risk of SPM and leukemic transformation, which may compromise long-term survival.

Quality Evaluation of Shelled and Unshelled Macadamia Nuts by Means of Near-Infrared Spectroscopy (NIR).

PubMed

Canneddu, Giovanna; Júnior, Luis Carlos Cunha; de Almeida Teixeira, Gustavo Henrique

2016-07-01

The quality of shelled and unshelled macadamia nuts was assessed by means of Fourier transformed near-infrared (FT-NIR) spectroscopy. Shelled macadamia nuts were sorted as sound nuts; nuts infected by Ecdytolopha aurantiana and Leucopteara coffeella; and cracked nuts caused by germination. Unshelled nuts were sorted as intact nuts (<10% half nuts, 2014); half nuts (March, 2013; November, 2013); and crushed nuts (2014). Peroxide value (PV) and acidity index (AI) were determined according to AOAC. PCA-LDA shelled macadamia nuts classification resulted in 93.2% accurate classification. PLS PV prediction model resulted in a square error of prediction (SEP) of 3.45 meq/kg, and a prediction coefficient determination value (Rp (2) ) of 0.72. The AI PLS prediction model was better (SEP = 0.14%, Rp (2) = 0.80). Although adequate classification was possible (93.2%), shelled nuts must not contain live insects, therefore the classification accuracy was not satisfactory. FT-NIR spectroscopy can be successfully used to predict PV and AI in unshelled macadamia nuts, though. © 2016 Institute of Food Technologists®

Reimagining the School Leadership Paradigm in a Postsocialist Context

ERIC Educational Resources Information Center

Magno, Cathryn

2009-01-01

Although Azerbaijan's education sector has experienced intermittent democratization efforts since independence from the Soviet Union in 1991, school leadership has remained untouched. This article argues that while Anglo-American models such as transformational and distributed leadership could benefit the schools, based on interview and…

Recycling WEEE: Polymer characterization and pyrolysis study for waste of crystalline silicon photovoltaic modules.

PubMed

Dias, Pablo; Javimczik, Selene; Benevit, Mariana; Veit, Hugo

2017-02-01

Photovoltaic (PV) modules contain both valuable and hazardous materials, which makes its recycling meaningful economically and environmentally. In general, the recycling of PV modules starts with the removal of the polymeric ethylene-vinyl acetate (EVA) resin using pyrolysis, which assists in the recovery of materials such as silicon, copper and silver. The pyrolysis implementation, however, needs improvement given its importance. In this study, the polymers in the PV modules were characterized by Fourier transform infrared spectroscopy (FTIR) and the removal of the EVA resin using pyrolysis has been studied and optimized. The results revealed that 30min pyrolysis at 500°C removes >99% of the polymers present in photovoltaic modules. Moreover, the behavior of different particle size milled modules during the pyrolysis process was evaluated. It is shown that polymeric materials tend to remain at a larger particle size and thus, this fraction has the greatest mass loss during pyrolysis. A thermo gravimetric analysis (TGA) performed in all polymeric matter revealed the optimum pyrolysis temperature is around 500°C. Temperatures above 500°C continue to degrade matter, but mass loss rate is 6.25 times smaller. This study demonstrates the use of pyrolysis can remove >99% of the polymeric matter from PV modules, which assists the recycling of this hazardous waste and avoids its disposal. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intermittent gravity: How much, how often, how long?

NASA Technical Reports Server (NTRS)

Vernikos, Joan; Ludwig, David A.

1994-01-01

Continuous exposure to gravity may not be necessary to prevent the deconditioning effects of microgravity. It is not known, however, what the minimum gravity (G) exposure reguirements are, whether they vary for different physiological systems, or whether passive Gz (gravity in the head-to-toe vector) or activity in a G field is more effective in preventing deconditioning. It is also not known what the optimal characteristics of the G stimulus should be in terms of amplitude, duration, and frequency. To begin to address these questions, a 4-day -6 deg head-down bed rest (HDBR) study was conducted. Nine males (aged 30-50 yr) were subjected, over a period of seven months, to four different +1 Gz exposure protocols (periodic standing or controlled walking each for a total of 2 or 4 hr/day in individual 15-min doses), plus a control (0 Gz) of continuous HDBR. The study consisted of one ambulatory control day, 4 full days of -6 deg HDBR, and a recovery day when subjects were released at the end of HDBR after completion of tests. A battery of tests was selected and standardized in order to evaluate the known early responses to HDBR. Dependent variables of interest included orthostatic tolerance (30 min at 60 deg head-up tilt) and hemodynamics during head-up tilt, peak oxygen consumption (VO2(sub peak)) plasma volume (PV), and urinary calcium (Ca). The results were as follows: 4 hr standing completely prevented and 2 hr walking partially prevented post-HDBR orthostatic intolerance. Walking at 3 mi/hr for 4 hr/day provided no additional benefit. Intermittent walking attenuated, but did not prevent, the decrease in VO2(sub peak). Both 4 hr conditions showed less PV loss by the end of HDBR; both 2 hr conditions were without effect. Both 2 and 4 hr walking essentially prevented urinary Ca excretion and were more effective than standing. It is concluded that different physiological systems benefit differentially from passive +1 Gz or activity in +1 Gz, and the intensity of the stimulus may be an important contributing factor.

Cortisol and interleukin-6 responses during intermittent exercise in two different hot environments with equivalent WBGT.

PubMed

Wright, Heather E; McLellan, Tom M; Stapleton, Jill M; Hardcastle, Stephen G; Kenny, Glen P

2012-01-01

Blood marker concentrations such as cortisol (COR) and interleukin (IL)-6 are commonly used to evaluate the physiological strain associated with work in the heat. It is unclear, however, if hot environments of an equivalent thermal stress, as defined by a similar wet bulb globe temperature (WBGT), result in similar response patterns. This study examined markers of neuroendocrine (COR) and immune (IL-6) responses, as well as the cardiovascular and thermal responses, relative to changes in body heat content measured by whole-body direct calorimetry during work in two different hot environments with equivalent WBGT. Eight males performed a 2-hr heavy intermittent exercise protocol (six 15-min bouts of cycling at a constant rate of metabolic heat production (360W) interspersed by 5-min rest periods) in Hot/Dry (46°C, 10% relative humidity [RH]) and Warm/Humid (33°C, 60% RH) conditions (WBGT ∼ 29°C). Whole-body evaporative and dry heat exchange, change in body heat content (ΔH(b)), rectal temperature (T(re)), and heart rate were measured continuously. Venous blood was obtained at rest (PRE) and the end of each exercise bout for the measurement of changes in plasma volume (PV), plasma protein (an estimate of plasma water changes), COR, and IL-6. Ratings of perceived exertion and thermal sensation were measured during the last minute of each exercise bout. No differences existed for ΔH(b), heart rate, T(re),%ΔPV, plasma protein concentration, perceptual strain (thermal sensation, perceived exertion), and COR between the Hot/Dry and Warm/Humid conditions. IL-6 exhibited an interaction effect (p = 0.041), such that greater increases were observed in the Hot/Dry (Δ = 1.61 pg·mL(-1)) compared with the Warm/Humid (Δ = 0.64 pg·mL(-1)) environment. These findings indicate that work performed in two different hot environments with equivalent WBGT resulted in similar levels of thermal, cardiovascular, and perceptual strain, which support the use of the WBGT stress index. However, the greater IL-6 response in the Hot/Dry requires further research to elucidate the effects of different hot environments and work intensities.

Unsteady propulsion by an intermittent swimming gait

NASA Astrophysics Data System (ADS)

Akoz, Emre; Moored, Keith W.

2018-01-01

Inviscid computational results are presented on a self-propelled swimmer modeled as a virtual body combined with a two-dimensional hydrofoil pitching intermittently about its leading edge. Lighthill (1971) originally proposed that this burst-and-coast behavior can save fish energy during swimming by taking advantage of the viscous Bone-Lighthill boundary layer thinning mechanism. Here, an additional inviscid Garrick mechanism is discovered that allows swimmers to control the ratio of their added mass thrust-producing forces to their circulatory drag-inducing forces by decreasing their duty cycle, DC, of locomotion. This mechanism can save intermittent swimmers as much as 60% of the energy it takes to swim continuously at the same speed. The inviscid energy savings are shown to increase with increasing amplitude of motion, increase with decreasing Lighthill number, Li, and switch to an energetic cost above continuous swimming for sufficiently low DC. Intermittent swimmers are observed to shed four vortices per cycle that form into groups that are self-similar with the DC. In addition, previous thrust and power scaling laws of continuous self-propelled swimming are further generalized to include intermittent swimming. The key is that by averaging the thrust and power coefficients over only the bursting period then the intermittent problem can be transformed into a continuous one. Furthermore, the intermittent thrust and power scaling relations are extended to predict the mean speed and cost of transport of swimmers. By tuning a few coefficients with a handful of simulations these self-propelled relations can become predictive. In the current study, the mean speed and cost of transport are predicted to within 3% and 18% of their full-scale values by using these relations.

Synthesis and Equation of State of Perovskites and Post-Perovskites in the (Mg,Fe)GeO3 System

NASA Astrophysics Data System (ADS)

Stan, C. V.; Dutta, R.; Krizan, J. W.; Cava, R. J.; Prakapenka, V.; Duffy, T. S.

2016-12-01

Knowledge of the effect of Fe on the physical and chemical properties of bridgmanite (perovskite, pv) and post-perovskite (ppv) is essential for interpreting seismic and geodynamic studies of the deep Earth. Silicate ppv is especially challenging to study due to the high pressure and temperature required for its synthesis ( 125 GPa and 2500 K in MgSiO3). This restricts the range of experiments possible and makes it very difficult to achieve well-characterized pressure-temperature conditions. Germanates have often been used as analogues because they undergo a similar sequence of phase transitions, but at lower pressures than their silicate counterparts. For example, MgGeO3 ppv can be synthesized at 63 GPa and 1800 K. In this study, polycrystalline pyroxenes (px) with compositions of (MgxFe1-x)2Ge2O6 (x = 1, 0.92, 0.78, 0.61, 0.52, 0) were synthesized and characterized using x-ray diffraction, Raman, Mössbauer, and microprobe analysis at ambient conditions. The px samples were found to exhibit a linear increase in lattice parameters and Raman mode shift with iron content. High-pressure x-ray diffraction experiments in the laser-heated diamond anvil cell were performed at beamline 13-ID-D of the Advanced Photon Source. All compositions were shown to transform to the pv ( 30 GPa and 1500 K) and ppv (> 55 GPa, 1600-1800 K) structures. Compositions with Mg# > 78 formed single-phase pv and ppv. Incorporation of Fe into the pv structure causes a decrease in octahedral distortion relative to the ideal cubic pv. Additionally, it leads to a modest decrease in bulk modulus (K0) and a modest increase in zero pressure volume (V0), and lowers the pv to ppv phase transition pressure by 10 GPa in the case of Mg#78 versus Mg#100. These novel high-pressure and -temperature analog phases can be of use for further investigation of the effect of Fe on the behavior of pv and ppv, including studies of site occupancies, spin state, and partitioning behavior.

Switchgrass (Panicum virgatum L.) promoters for green tissue-specific expression of the MYB4 transcription factor for reduced-recalcitrance transgenic switchgrass

DOE PAGES

Liu, Wusheng; Mazarei, Mitra; Ye, Rongjian; ...

2018-04-24

Genetic engineering of switchgrass (Panicum virgatum L.) for reduced cell wall recalcitrance and improved biofuel production has been a long pursued goal. Up to now, constitutive promoters have been used to direct the expression of cell wall biosynthesis genes toward attaining that goal. While generally sufficient to gauge a transgene's effects in the heterologous host, constitutive overexpression often leads to undesirable plant phenotypic effects. Green tissue-specific promoters from switchgrass are potentially valuable to directly alter cell wall traits exclusively in harvestable aboveground biomass while not changing root phenotypes. We identified and functionally characterized three switchgrass green tissue-specific promoters and assessedmore » marker gene expression patterns and intensity in stably transformed rice (Oryza sativa L.), and then used them to direct the expression of the switchgrass MYB4 (PvMYB4) transcription factor gene in transgenic switchgrass to endow reduced recalcitrance in aboveground biomass. These promoters correspond to photosynthesis-related light-harvesting complex II chlorophyll-a/b binding gene (PvLhcb), phosphoenolpyruvate carboxylase (PvPEPC), and the photosystem II 10 kDa R subunit (PvPsbR). Real-time RT-PCR analysis detected their strong expression in the aboveground tissues including leaf blades, leaf sheaths, internodes, inflorescences, and nodes of switchgrass, which was tightly up-regulated by light. Stable transgenic rice expressing the GUS reporter under the control of each promoter (756-2005 bp in length) further confirmed their strong expression patterns in leaves and stems. With the exception of the serial promoter deletions of PvLhcb, all GUS marker patterns under the control of each 5'-end serial promoter deletion were not different from that conveyed by their respective promoters. All of the shortest promoter fragments (199-275 bp in length) conveyed strong green tissue-specific GUS expression in transgenic rice. PvMYB4 is a master repressor of lignin biosynthesis. The green tissue-specific expression of PvMYB4 via each promoter in transgenic switchgrass led to significant gains in saccharification efficiency, decreased lignin, and decreased S/G lignin ratios. In contrast to constitutive overexpression of PvMYB4, which negatively impacts switchgrass root growth, plant growth was not compromised in green tissue-expressed PvMYB4 switchgrass plants in the current study. Each of the newly described green tissue-specific promoters from switchgrass has utility to change cell wall biosynthesis exclusively in aboveground harvestable biomass without altering root systems. The truncated green tissue promoters are very short and should be useful for targeted expression in a number of monocots to improve shoot traits while restricting gene expression from roots. Green tissue-specific expression of PvMYB4 is an effective strategy for improvement of transgenic feedstocks.« less

Switchgrass (Panicum virgatum L.) promoters for green tissue-specific expression of the MYB4 transcription factor for reduced-recalcitrance transgenic switchgrass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Wusheng; Mazarei, Mitra; Ye, Rongjian

Genetic engineering of switchgrass (Panicum virgatum L.) for reduced cell wall recalcitrance and improved biofuel production has been a long pursued goal. Up to now, constitutive promoters have been used to direct the expression of cell wall biosynthesis genes toward attaining that goal. While generally sufficient to gauge a transgene's effects in the heterologous host, constitutive overexpression often leads to undesirable plant phenotypic effects. Green tissue-specific promoters from switchgrass are potentially valuable to directly alter cell wall traits exclusively in harvestable aboveground biomass while not changing root phenotypes. We identified and functionally characterized three switchgrass green tissue-specific promoters and assessedmore » marker gene expression patterns and intensity in stably transformed rice (Oryza sativa L.), and then used them to direct the expression of the switchgrass MYB4 (PvMYB4) transcription factor gene in transgenic switchgrass to endow reduced recalcitrance in aboveground biomass. These promoters correspond to photosynthesis-related light-harvesting complex II chlorophyll-a/b binding gene (PvLhcb), phosphoenolpyruvate carboxylase (PvPEPC), and the photosystem II 10 kDa R subunit (PvPsbR). Real-time RT-PCR analysis detected their strong expression in the aboveground tissues including leaf blades, leaf sheaths, internodes, inflorescences, and nodes of switchgrass, which was tightly up-regulated by light. Stable transgenic rice expressing the GUS reporter under the control of each promoter (756-2005 bp in length) further confirmed their strong expression patterns in leaves and stems. With the exception of the serial promoter deletions of PvLhcb, all GUS marker patterns under the control of each 5'-end serial promoter deletion were not different from that conveyed by their respective promoters. All of the shortest promoter fragments (199-275 bp in length) conveyed strong green tissue-specific GUS expression in transgenic rice. PvMYB4 is a master repressor of lignin biosynthesis. The green tissue-specific expression of PvMYB4 via each promoter in transgenic switchgrass led to significant gains in saccharification efficiency, decreased lignin, and decreased S/G lignin ratios. In contrast to constitutive overexpression of PvMYB4, which negatively impacts switchgrass root growth, plant growth was not compromised in green tissue-expressed PvMYB4 switchgrass plants in the current study. Each of the newly described green tissue-specific promoters from switchgrass has utility to change cell wall biosynthesis exclusively in aboveground harvestable biomass without altering root systems. The truncated green tissue promoters are very short and should be useful for targeted expression in a number of monocots to improve shoot traits while restricting gene expression from roots. Green tissue-specific expression of PvMYB4 is an effective strategy for improvement of transgenic feedstocks.« less

Application of multivariate chemometric techniques for simultaneous determination of five parameters of cottonseed oil by single bounce attenuated total reflectance Fourier transform infrared spectroscopy.

PubMed

Talpur, M Younis; Kara, Huseyin; Sherazi, S T H; Ayyildiz, H Filiz; Topkafa, Mustafa; Arslan, Fatma Nur; Naz, Saba; Durmaz, Fatih; Sirajuddin

2014-11-01

Single bounce attenuated total reflectance (SB-ATR) Fourier transform infrared (FTIR) spectroscopy in conjunction with chemometrics was used for accurate determination of free fatty acid (FFA), peroxide value (PV), iodine value (IV), conjugated diene (CD) and conjugated triene (CT) of cottonseed oil (CSO) during potato chips frying. Partial least square (PLS), stepwise multiple linear regression (SMLR), principal component regression (PCR) and simple Beer׳s law (SBL) were applied to develop the calibrations for simultaneous evaluation of five stated parameters of cottonseed oil (CSO) during frying of French frozen potato chips at 170°C. Good regression coefficients (R(2)) were achieved for FFA, PV, IV, CD and CT with value of >0.992 by PLS, SMLR, PCR, and SBL. Root mean square error of prediction (RMSEP) was found to be less than 1.95% for all determinations. Result of the study indicated that SB-ATR FTIR in combination with multivariate chemometrics could be used for accurate and simultaneous determination of different parameters during the frying process without using any toxic organic solvent. Copyright © 2014 Elsevier B.V. All rights reserved.

Stem Inc. SunShot Incubator Program Final Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butterfield, Karen

In this Energy Storage Control Algorithms project, Stem sought to develop tools and control algorithms to increase the value and reduce balance-of-system and grid integration costs associated with adding distributed solar generation to the grid. These advances fell under the headings SolarScope and SolarController. Stem sought to create initial market traction with a fully commercialized product for the solar industry to size storage systems (SolarScope) as well as a solar intermittency-mitigation framework for utilities (SolarController) in the course of the project. The company sought to align strategic growth plans and enable the rollout of the products to broader audiences inmore » multiple geographic regions by leveraging the major solar companies in the national market as partners. Both final products were both intended to be commercialized. They are: SolarScope: Analysis tool to identify viable PV + storage projects and thereby expedite the sales and interconnection processes. SolarScope combines customer load data, PV production estimates, utility rate tariff, and simulated storage into a simple user interface for PV developers. Developers can easily identify viable solar + storage sites without the need for complex and time consuming, site-by-site spreadsheet modeling. SolarContoller: Tool to autonomously dispatch distributed storage in order to mitigate voltage fluctuation and reduce curtailment. SolarController co-optimizes, in real time, storage dispatch for circuit stability and curtailment reduction, enabling higher penetrations of PV. SolarController is automated, not requiring utility dispatch or management, as Stem hardware senses grid voltage, frequency, customer load, PV production, and power factor. In the end the two products met with different outcomes. SolarScope was tested by potential users, and continues to be used as a foundational platform for partnership with key solar industry partners. SolarController, on the other hand, was successful in lab testing but was not commercialized due to a lack of marketability and lack of interested customer base. Together the development of these two products marked a material step forward for Stem; and a new milestone along the pathway of integration for the solar and storage industries. SolarScope is leading to real, out-of-the-lab project development in storage + solar for the commercial customer sector. Meanwhile SolarController has opened the eyes of regulators and utility executives alike to the potential of distributed solar and by doing so, has moved the conversation forward for the integration of distributed energy resources more broadly on the grid.« less

A reliable in vitro fruiting system for armillaria mellea for evaluation of agrobacterium tumefaciens transformation vectors

USDA-ARS?s Scientific Manuscript database

Armillaria mellea is a serious pathogen of horticultural and agricultural systems in Europe and North America. The lack of a reliable in vitro fruiting system has hindered research, and necessitated dependence on intermittently available wild-collected basidiospores. Here we describe a reliable, rep...

Manipulation for plasmid elimination by transforming synthetic competitors diversifies lactococcus lactis starters applicable to food products.

PubMed

Kobayashi, Miho; Nomura, Masaru; Kimoto, Hiromi

2007-11-01

This study was designed selectively to eliminate a theta-plasmid from Lactococcus lactis strains by transforming synthetic competitors. A shuttle vector for Escherichia coli and L. lactis, pDB1, was constructed by ligating a partial replicon of pDR1-1B, which is a 7.3 kb theta-plasmid in L. lactis DRC1, with an erythromycin resistance gene into pBluescript II KS(+). This versatile vector was used to construct competitors to common lactococcal theta-plasmids. pDB1 contains the 5' half of the replication origin and the 3' region of repB of pDR1-1B, but lacks the 1.1-kb region normally found between these two segments. A set of primers, Pv3 and Pv4, was designed to amplify the 1.1-kb middle parts of the general theta-replicons of lactococcal plasmids. When the PCR products were cloned into the Nru I and Xho I sites of pDB1, synthetic replicons were constructed and replication activity was restored. A number of theta-plasmids in L. lactis ssp. lactis and cremoris were eliminated selectively by transforming the synthetic competitors. These competitors were easily eliminated by subculture for a short time in the absence of selection. The resulting variants contained no exogenous DNA and are suitable for food products, since part of the phenotype was altered without altering other plasmids indispensable for fermentation.

Trimode Power Converter optimizes PV, diesel and battery energy sources

NASA Astrophysics Data System (ADS)

Osullivan, George; Bonn, Russell; Bower, Ward

1994-12-01

Conservatively, there are 100,000 localities in the world waiting for the benefits that electricity can provide, and many of these are in climates where sunshine is plentiful. With these locations in mind a prototype 30 kW hybrid system has been assembled at Sandia to prove the reliability and economics of photovoltaic, diesel and battery energy sources managed by an autonomous power converter. In the Trimode Power Converter the same power parts, four IGBT's with an isolation transformer and filter components, serve as rectifier and charger to charge the battery from the diesel; as a stand-alone inverter to convert PV and battery energy to AC; and, as a parallel inverter with the diesel-generator to accommodate loads larger than the rating of the diesel. Whenever the diesel is supplying the load, an algorithm assures that the diesel is running at maximum efficiency by regulating the battery charger operating point. Given the profile of anticipated solar energy, the cost of transporting diesel fuel to a remote location and a five year projection of load demand, a method to size the PV array, battery and diesel for least cost is developed.

Decentralized Dimensionality Reduction for Distributed Tensor Data Across Sensor Networks.

PubMed

Liang, Junli; Yu, Guoyang; Chen, Badong; Zhao, Minghua

2016-11-01

This paper develops a novel decentralized dimensionality reduction algorithm for the distributed tensor data across sensor networks. The main contributions of this paper are as follows. First, conventional centralized methods, which utilize entire data to simultaneously determine all the vectors of the projection matrix along each tensor mode, are not suitable for the network environment. Here, we relax the simultaneous processing manner into the one-vector-by-one-vector (OVBOV) manner, i.e., determining the projection vectors (PVs) related to each tensor mode one by one. Second, we prove that in the OVBOV manner each PV can be determined without modifying any tensor data, which simplifies corresponding computations. Third, we cast the decentralized PV determination problem as a set of subproblems with consensus constraints, so that it can be solved in the network environment only by local computations and information communications among neighboring nodes. Fourth, we introduce the null space and transform the PV determination problem with complex orthogonality constraints into an equivalent hidden convex one without any orthogonality constraint, which can be solved by the Lagrange multiplier method. Finally, experimental results are given to show that the proposed algorithm is an effective dimensionality reduction scheme for the distributed tensor data across the sensor networks.

Hybrid solar collector using nonimaging optics and photovoltaic components

NASA Astrophysics Data System (ADS)

Winston, Roland; Yablonovitch, Eli; Jiang, Lun; Widyolar, Bennett K.; Abdelhamid, Mahmoud; Scranton, Gregg; Cygan, David; Kozlov, Alexandr

2015-08-01

The project team of University of California at Merced (UC-M), Gas Technology Institute, and Dr. Eli Yablonovitch of University of California at Berkeley developed a novel hybrid concentrated solar photovoltaic thermal (PV/T) collector using nonimaging optics and world record single-junction Gallium arsenide (GaAs) PV components integrated with particle laden gas as thermal transfer and storage media, to simultaneously generate electricity and high temperature dispatchable heat. The collector transforms a parabolic trough, commonly used in CSP plants, into an integrated spectrum-splitting device. This places a spectrum-sensitive topping element on a secondary reflector that is registered to the thermal collection loop. The secondary reflector transmits higher energy photons for PV topping while diverting the remaining lower energy photons to the thermal media, achieving temperatures of around 400°C even under partial utilization of the solar spectrum. The collector uses the spectral selectivity property of Gallium arsenide (GaAs) cells to maximize the exergy output of the system, resulting in an estimated exergy efficiency of 48%. The thermal media is composed of fine particles of high melting point material in an inert gas that increases heat transfer and effectively stores excess heat in hot particles for later on-demand use.

The value prescription: relative value theorem as a call to action.

PubMed

Alston, Greg L; Blizzard, Joseph C

2012-01-01

The Joint Commission of Pharmacy Practitioners Future Vision of Pharmacy Practice 2015 (2005) and Project Destiny (2008) clearly defined a vision for transforming community practice pharmacy from a culture of dispensing drugs to the provision of services. Several viable service offerings were identified. Pharmacy has not yet fully capitalized on these opportunities. Pharmacy must demonstrate value in providing these services to remain viable in the marketplace. Many pharmacists do not understand how value is created and lack sufficient marketing skills to position their practice for long-term success. The relative value theorem (RVT) describes in simple terms the key elements that drive purchase decisions and thus marketing decisions: (P+S)×PV=RV (P, price; S, service; PV, perceived value; RV, relative value). A consumer compares the P, extra S, and PV of the purchase against all potential uses of their scarce resources before deciding what to buy. Evidence suggests that understanding and applying the principles of RVT is a critical skill for pharmacy professionals in all practice settings to master if they plan to remain viable players in the health care marketplace of the future. Copyright © 2012 Elsevier Inc. All rights reserved.

Can Integrated Micro-Optical Concentrator Technology Revolutionize Flat-Plate Photovoltaic Solar Energy Harvesting?

NASA Astrophysics Data System (ADS)

Haney, Michael W.

2015-12-01

The economies-of-scale and enhanced performance of integrated micro-technologies have repeatedly delivered disruptive market impact. Examples range from microelectronics to displays to lighting. However, integrated micro-scale technologies have yet to be applied in a transformational way to solar photovoltaic panels. The recently announced Micro-scale Optimized Solar-cell Arrays with Integrated Concentration (MOSAIC) program aims to create a new paradigm in solar photovoltaic panel technology based on the incorporation of micro-concentrating photo-voltaic (μ-CPV) cells. As depicted in Figure 1, MOSAIC will integrate arrays of micro-optical concentrating elements and micro-scale PV elements to achieve the same aggregated collection area and high conversion efficiency of a conventional (i.e., macro-scale) CPV approach, but with the low profile and mass, and hopefully cost, of a conventional non-concentrated PV panel. The reduced size and weight, and enhanced wiring complexity, of the MOSAIC approach provide the opportunity to access the high-performance/low-cost region between the conventional CPV and flat-plate (1-sun) PV domains shown in Figure 2. Accessing this portion of the graph in Figure 2 will expand the geographic and market reach of flat-plate PV. This talk reviews the motivation and goals for the MOSAIC program. The diversity of the technical approaches to micro-concentration, embedded solar tracking, and hybrid direct/diffuse solar resource collection found in the MOSAIC portfolio of projects will also be highlighted.

Rapid cell death in Xanthomonas campestris pv. glycines.

PubMed

Gautam, Satyendra; Sharma, Arun

2002-04-01

Xanthomonas campestris pv. glycines strain AM2 (XcgAM2), the etiological agent of bacterial pustule disease of soybean, exhibited post-exponential rapid cell death (RCD) in LB medium. X. campestris pv. malvacearum NCIM 2310 and X. campestris NCIM 2961 also displayed RCD, though less pronouncedly than XcgAM2. RCD was not observed in Pseudomonas syringae pv. glycines, or Escherichia coli DH5alpha. Incubation of the post-exponential LB-grown XcgAM2 cultures at 4 degrees C arrested the RCD. RCD was also inhibited by the addition of starch during the exponential phase of LB-growing XcgAM2. Protease negative mutants of XcgAM2 were found to be devoid of RCD behavior observed in the wild type XcgAM2. While undergoing RCD, the organism was found to transform to spherical membrane bodies. The presence of membrane bodies was confirmed by using a membrane specific fluorescent label, 1,6-diphenyl 1,3,5-hexatriene (DPH), and also by visualizing these structures under microscope. The membrane bodies of XcgAM2 were found to contain DNA, which was devoid of the indigenous plasmids of the organism. The membrane bodies were found to bind annexin V indicative of the externalization of membrane phosphatidyl serine. Nicking of DNA in XcgAM2 cultures undergoing RCD in LB medium was also detected using a TUNEL assay. The RCD in XcgAM2 appeared to have features similar to the programmed cell death in eukaryotes.

Two-stage single-phase grid-connected photovoltaic system with reduced complexity

NASA Astrophysics Data System (ADS)

da Silva, Cintia S.; Motta, Filipe R.; Tofoli, Fernando L.

2011-06-01

This article presents a grid-connected photovoltaic (PV) system using the classical DC-DC buck converter, which is responsible for stepping down the resulting voltage from several series-connected panels. Besides, the structure provides high power factor operation by injecting a quasi-sinusoidal current into the grid, with near no displacement in relation to the line voltage at the point of common coupling among the PV system and the loads. A CSI employing thyristors is cascaded with the DC-DC stage so that AC voltage results. The inverter output voltage level is adjusted by using a low-frequency transformer, which also provides galvanic isolation. The proposed system is described as mathematical approach and design guidelines are presented, providing an overview of the topology. An experimental prototype is also implemented, and relevant results to validate the proposal are discussed.

Adding heat to the live-high train-low altitude model: a practical insight from professional football

PubMed Central

Buchheit, M; Racinais, S; Bilsborough, J; Hocking, J; Mendez-Villanueva, A; Bourdon, P C; Voss, S; Livingston, S; Christian, R; Périard, J; Cordy, J; Coutts, A J

2013-01-01

Objectives To examine with a parallel group study design the performance and physiological responses to a 14-day off-season ‘live high-train low in the heat’ training camp in elite football players. Methods Seventeen professional Australian Rules Football players participated in outdoor football-specific skills (32±1°C, 11.5 h) and indoor strength (23±1°C, 9.3 h) sessions and slept (12 nights) and cycled indoors (4.3 h) in either normal air (NORM, n=8) or normobaric hypoxia (14±1 h/day, FiO2 15.2–14.3%, corresponding to a simulated altitude of 2500–3000 m, hypoxic (HYP), n=9). They completed the Yo-Yo Intermittent Recovery level 2 (Yo-YoIR2) in temperate conditions (23±1°C, normal air) precamp (Pre) and postcamp (Post). Plasma volume (PV) and haemoglobin mass (Hbmass) were measured at similar times and 4 weeks postcamp (4WPost). Sweat sodium concentration ((Na+)sweat) was measured Pre and Post during a heat-response test (44°C). Results Both groups showed very large improvements in Yo-YoIR2 at Post (+44%; 90% CL 38, 50), with no between-group differences in the changes (−1%; −9, 9). Postcamp, large changes in PV (+5.6%; −1.8, 5.6) and (Na+)sweat (−29%; −37, −19) were observed in both groups, while Hbmass only moderately increased in HYP (+2.6%; 0.5, 4.5). At 4WPost, there was a likely slightly greater increase in Hbmass (+4.6%; 0.0, 9.3) and PV (+6%; −5, 18, unclear) in HYP than in NORM. Conclusions The combination of heat and hypoxic exposure during sleep/training might offer a promising ‘conditioning cocktail’ in team sports. PMID:24282209

Assessing the environmental sustainability of electricity generation in Chile.

PubMed

Gaete-Morales, Carlos; Gallego-Schmid, Alejandro; Stamford, Laurence; Azapagic, Adisa

2018-09-15

Around 40% of electricity in Chile is supplied by renewables and the rest by fossil fuels. Despite the growing electricity demand in the country, its environmental impacts are as yet unknown. To address this gap, the current study presents the first comprehensive assessment of the life cycle environmental sustainability of electricity generation in Chile. Both the individual sources and the electricity mix over the past 10 years are considered. The following sources present in the electricity mix are evaluated: coal, oil, natural gas, biogas, biomass, wind, solar photovoltaics (PV) and hydropower. In total, 10 electricity technologies and 174 power plants installed across the country have been considered. Eleven environmental impacts have been estimated, including global warming, human toxicity, ecotoxicities, as well as resource and ozone layer depletion. The results reveal that hydropower is environmentally the most sustainable option across the impacts, followed by onshore wind and biogas. Electricity from natural gas has 10%-84% lower impacts than biomass for seven categories. It is also 13%-98% better than solar PV for six impacts and 17%-66% than wind for four categories. Solar PV has the highest abiotic depletion potential due to the use of scarce elements in the manufacture of panels. While electricity generation has grown by 44% in the past 10 years, all the impacts except ozone layer depletion have increased by 1.6-2.7 times. In the short term, environmental regulations should be tightened to improve the emissions control from coal and biomass plants. In the medium term, the contribution of renewables should be ramped up, primarily increasing the hydro, wind and biogas capacity. Coal and oil should be phased out, using natural gas as a transitional fuel to help the stability of the grid with the increasing contribution of intermittent renewables. Copyright © 2018 Elsevier B.V. All rights reserved.

Locomotion characteristics and match-induced impairments in physical performance in male elite team handball players.

PubMed

Michalsik, L B; Aagaard, P; Madsen, K

2013-07-01

The purpose of this study was to determine the physical demands and match-induced impairments in physical performance in male elite Team Handball (TH) players in relation to playing position. Male elite TH field players were closely observed during 6 competitive seasons. Each player (wing players: WP, pivots: PV, backcourt players: BP) was evaluated during match-play using video recording and subsequently performing locomotion match analysis. A total distance of 3 627±568 m (group means±SD) was covered per match with a total effective playing time (TPT) of 53:51±5:52 min:s, while full-time players covered 3 945±538 m. The mean speed was 6.40±1.01 km · h - 1. High-intensity running constituted only 1.7±0.9% of TPT per match corresponding to 7.9±4.9% of the total distance covered. An average of 1 482.4±312.6 activity changes per player (n=82) with 53.2±14.1 high-intensity runs were observed per match. Total distance covered was greater in BP (3 765±532 m) and WP (3 641±501 m) than PV (3 295±495 m) (p<0.05), and WP performed more high-intensity running (10.9±5.7% of total distance covered) than PV (8.5±4.3%, p<0.05) and BP (6.2±3.2%, p<0.01). The amount of high-intensity running was lower (p<0.05) in the second (130.4±38.4 m) than in the first half (155.3±47.6 m) corresponding to a decrease of 16.2%.In conclusion, modern male elite TH is a complex team sport that comprises several types of movement categories, which during match-play place moderate-to-high demands on intermittent endurance running capacity and where the amount of high-intensity running may be high during brief periods of the match. Signs of fatigue-related changes were observed in terms of temporary impaired physical performance, since the amount of high-intensity running was reduced in the second half. Notably, physical demands differed between playing positions, with WP demonstrating a more intensive activity pattern than BP and PV, respectively. © Georg Thieme Verlag KG Stuttgart · New York.

Bacterial recovery and recycling of tellurium from tellurium-containing compounds by Pseudoalteromonas sp. EPR3.

PubMed

Bonificio, W D; Clarke, D R

2014-11-01

Tellurium-based devices, such as photovoltaic (PV) modules and thermoelectric generators, are expected to play an increasing role in renewable energy technologies. Tellurium, however, is one of the scarcest elements in the earth's crust, and current production and recycling methods are inefficient and use toxic chemicals. This study demonstrates an alternative, bacterially mediated tellurium recovery process. We show that the hydrothermal vent microbe Pseudoalteromonas sp. strain EPR3 can convert tellurium from a wide variety of compounds, industrial sources and devices into metallic tellurium and a gaseous tellurium species. These compounds include metallic tellurium (Te(0)), tellurite (TeO3(2-)), copper autoclave slime, tellurium dioxide (TeO2), tellurium-based PV material (cadmium telluride, CdTe) and tellurium-based thermoelectric material (bismuth telluride, Bi2Te3). Experimentally, this was achieved by incubating these tellurium sources with the EPR3 in both solid and liquid media. Despite the fact that many of these tellurium compounds are considered insoluble in aqueous solution, they can nonetheless be transformed by EPR3, suggesting the existence of a steady state soluble tellurium concentration during tellurium transformation. These experiments provide insights into the processes of tellurium precipitation and volatilization by bacteria, and their implications on tellurium production and recycling. © 2014 The Society for Applied Microbiology.

Overexpression of bacterial ethylene-forming enzyme gene in Trichoderma reesei enhanced the production of ethylene

PubMed Central

Chen, Xi; Liang, Yong; Hua, Jing; Tao, Li; Qin, Wensheng; Chen, Sanfeng

2010-01-01

In order to efficiently utilize natural cellulose materials to produce ethylene, three expression vectors containing the ethylene-forming enzyme (efe) gene from Pseudomonas syringae pv. glycinea were constructed. The target gene was respectively controlled by different promoters: cbh I promoter from Trichoderma reesei cellobiohydrolases I gene, gpd promoter from Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase gene and pgk I promoter from T. reesei 3-phosphoglycerate kinase I gene. After transforming into T. reesei QM9414, 43 stable transformants were obtained by PCR amplification and ethylene determination. Southern blot analysis of 14 transformants demonstrated that the efe gene was integrated into chromosomal DNA with copy numbers from 1 to 4. Reverse transcription polymerase chain reaction (RT-PCR) analysis of 6 transformants showed that the heterologous gene was transcribed. By using wheat straw as a carbon source, the ethylene production rates of aforementioned 14 transformants were measured. Transformant C30-3 with pgk I promoter had the highest ethylene production (4,012 nl h-1 l-1). This indicates that agricultural wastes could be used to produce ethylene in recombinant filamentous fungus T. reesei. PMID:20150979

Isolated orbital mass as the primary presentation of a triple-hit lymphoma transformed from a systemic follicular lymphoma.

PubMed

Zhou, Xiao Yi; Lu, Xinyan; Raparia, Kirtee; Chen, Yi-Hua

2018-06-01

Triple-hit lymphoma is a highly aggressive B-cell lymphoma. We report a case of triple-hit lymphoma transformed from systemic follicular lymphoma (FL) after 9-year remission and presented primarily as an isolated orbital mass without systemic symptoms or lymphadenopathy. A 58-year-old female presented with intermittent vertical binocular diplopia, left upper eyelid swelling and pain and was found to have a 2.9 cm orbital mass. Histological section revealed a CD10-positive large B-cell lymphoma, consistent with transformation of FL. Fluorescent in situ hybridization (FISH) analysis demonstrated rearrangements involving C-MYC, BCL-2 and BCL-6 genes, indicating a high grade, triple-hit lymphoma. Triple-hit lymphoma transformed from a low-grade lymphoma may initially present as an isolated orbital mass without systemic evidence of transformation. Early recognition of double or triple-hit lymphomas is important since these patients require aggressive chemotherapy.

Phase relations in a harzburgite composition: implications for splitting of 660-km seismic discontinuity and seismic velocities in mantle transition zone

NASA Astrophysics Data System (ADS)

Nishiyama, N.; Kato, T.; Kinoshita, Y.; Irifune, T.

2011-12-01

Subducting slab is composed of chemically differentiated rocks: The top layer is MORB, which is underlain by harzburgite, and the bottom part is undifferentiated mantle rock, pyrolite. Harzburgite is the residual of melting at mid oceanic ridge and is depleted in Al, Ca, and Fe. One of the roles of slab subduction is transportation of chemically differentiated rocks, MORB and harzburgite into the earth's interior. Seismic tomographic images show that slab stagnation at mantle transition zone (MTZ) occurs in many subduction zones, which implies that harzbrugite component exits in MTZ. We studied phase relations in a harzbugite composition at pressures between 16 and 25 GPa and at temperatures between 1673 and 1873 K. At 16.5 GPa, a mineral assemblage of wadsleyite (Wd) + clinopyroxene (CPx) + garnet (Gt) was observed, whereas, at 17.5 GPa, Wd + Gt + stishovite (St) was stabilized, which indicates that MgSiO3-rich component transforms into Wd + St at about 17 GPa (500 km depth). At about 18 GPa, we observed a phase transition from Wd to ringwoodite (Rw). The mineral assemblage, Rw + St + Gt, is stable between 18 and 21 GPa (520-600 km depth). At 22 GPa, the non-olivine component transforms into akimotoite (Ak) with minor Gt. The stability field of Ak is narrow and Ak to MgSiO3-rich perovskite (Pv) transition occurs at 22. 5 GPa, which indicates that Rw coexists with Pv at the bottom of MTZ in harzburgite. At 24 GPa, postspinel transition occurs in olivine component. In the Al-poor system, harzburgite, the Pv-forming transition in non-olivine component occurs at a pressure below the post-spinel transition. In general, harzburgite is less dense than the surrounding pyrolite because of the low Fe content, but, between 630 and 660 km depth, harzburgite with a mineral assemblage of Rw + Pv + Gt is denser than the surrounding pyrolite, which consists of Rw + Gt + Ca-perovskite. The high density of harzburgite at the bottom of MTZ is originated by the presence of a high density phase, Pv, and can cause the accumulation of harzburgite component at the base of MTZ. We calculated seismic velocities, Vp and Vs, of harzburgite using thermoelastic parameters determined in previous studies. Harzburgite is faster than pyrolite and 1D earth models, like PREM, at the lower half of MTZ (between 500 and 660 km depth) because of presence of St, Ak, and Pv in addition to the lower density caused by the low-Fe content. It has been demonstrated that pyrolite is slower than the 1D earth models in this region because of low velocity of majorite garnet. Mechanical mixture of pyrolite and harzgurgite can explain 1D earth models, which strongly indicates that harzburgite is accumulated and stagnant at the base of the MTZ. In addition, harzburgite can produce many seismic discontinuities in the non-olivine component, like Ak-Pv transition at 630 km depth, which are superimposed on phase transitions in olivine. Thus, presence of harzburgite in MTZ may explain regionally observed splitting of seismic discontinuities. The splitting of the seismic discontinuities may be caused by chemical heterogeneity, presence of harzburgite.

Unified theory for stochastic modelling of hydroclimatic processes: Preserving marginal distributions, correlation structures, and intermittency

NASA Astrophysics Data System (ADS)

Papalexiou, Simon Michael

2018-05-01

Hydroclimatic processes come in all "shapes and sizes". They are characterized by different spatiotemporal correlation structures and probability distributions that can be continuous, mixed-type, discrete or even binary. Simulating such processes by reproducing precisely their marginal distribution and linear correlation structure, including features like intermittency, can greatly improve hydrological analysis and design. Traditionally, modelling schemes are case specific and typically attempt to preserve few statistical moments providing inadequate and potentially risky distribution approximations. Here, a single framework is proposed that unifies, extends, and improves a general-purpose modelling strategy, based on the assumption that any process can emerge by transforming a specific "parent" Gaussian process. A novel mathematical representation of this scheme, introducing parametric correlation transformation functions, enables straightforward estimation of the parent-Gaussian process yielding the target process after the marginal back transformation, while it provides a general description that supersedes previous specific parameterizations, offering a simple, fast and efficient simulation procedure for every stationary process at any spatiotemporal scale. This framework, also applicable for cyclostationary and multivariate modelling, is augmented with flexible parametric correlation structures that parsimoniously describe observed correlations. Real-world simulations of various hydroclimatic processes with different correlation structures and marginals, such as precipitation, river discharge, wind speed, humidity, extreme events per year, etc., as well as a multivariate example, highlight the flexibility, advantages, and complete generality of the method.

PV source based high voltage gain current fed converter

NASA Astrophysics Data System (ADS)

Saha, Soumya; Poddar, Sahityika; Chimonyo, Kudzai B.; Arunkumar, G.; Elangovan, D.

2017-11-01

This work involves designing and simulation of a PV source based high voltage gain, current fed converter. It deals with an isolated DC-DC converter which utilizes boost converter topology. The proposed converter is capable of high voltage gain and above all have very high efficiency levels as proved by the simulation results. The project intends to produce an output of 800 V dc from a 48 V dc input. The simulation results obtained from PSIM application interface were used to analyze the performance of the proposed converter. Transformer used in the circuit steps up the voltage as well as to provide electrical isolation between the low voltage and high voltage side. Since the converter involves high switching frequency of 100 kHz, ultrafast recovery diodes are employed in the circuitry. The major application of the project is for future modeling of solar powered electric hybrid cars.

Financing Solar PV at Government Sites with PPAs and Public Debt (Brochure)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2011-11-01

Historically, state and local governmental agencies have employed one of two models to deploy solar photovoltaic (PV) projects: (1) self-ownership (financed through a variety of means) or (2) third-party ownership through a power purchase agreement (PPA). Morris County, New Jersey, administrators recently pioneered a way to combine many of the benefits of self-ownership and third-party PPAs through a bond-PPA hybrid, frequently referred to as the Morris Model. At the request of the Department of Energy's Solar Market Transformation group, NREL examined the hybrid model. This fact sheet describes how the hybrid model works, assesses the model's relative advantages and challengesmore » as compared to self-ownership and the third-party PPA model, provides a quick guide to project implementation, and assesses the replicability of the model in other jurisdictions across the United States.« less

Financing Solar PV at Government Sites with PPAs and Public Debt (Brochure)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2011-12-01

Historically, state and local governmental agencies have employed one of two models to deploy solar photovoltaic (PV) projects: (1) self-ownership (financed through a variety of means) or (2) third-party ownership through a power purchase agreement (PPA). Morris County, New Jersey, administrators recently pioneered a way to combine many of the benefits of self-ownership and third-party PPAs through a bond-PPA hybrid, frequently referred to as the Morris Model. At the request of the Department of Energy?s Solar Market Transformation group, NREL examined the hybrid model. This fact sheet describes how the hybrid model works, assesses the model?s relative advantages and challengesmore » as compared to self-ownership and the third-party PPA model, provides a quick guide to project implementation, and assesses the replicability of the model in other jurisdictions across the United States.« less

Power Flow Simulations of a More Renewable California Grid Utilizing Wind and Solar Insolation Forecasting

NASA Astrophysics Data System (ADS)

Hart, E. K.; Jacobson, M. Z.; Dvorak, M. J.

2008-12-01

Time series power flow analyses of the California electricity grid are performed with extensive addition of intermittent renewable power. The study focuses on the effects of replacing non-renewable and imported (out-of-state) electricity with wind and solar power on the reliability of the transmission grid. Simulations are performed for specific days chosen throughout the year to capture seasonal fluctuations in load, wind, and insolation. Wind farm expansions and new wind farms are proposed based on regional wind resources and time-dependent wind power output is calculated using a meteorological model and the power curves of specific wind turbines. Solar power is incorporated both as centralized and distributed generation. Concentrating solar thermal plants are modeled using local insolation data and the efficiencies of pre-existing plants. Distributed generation from rooftop PV systems is included using regional insolation data, efficiencies of common PV systems, and census data. The additional power output of these technologies offsets power from large natural gas plants and is balanced for the purposes of load matching largely with hydroelectric power and by curtailment when necessary. A quantitative analysis of the effects of this significant shift in the electricity portfolio of the state of California on power availability and transmission line congestion, using a transmission load-flow model, is presented. A sensitivity analysis is also performed to determine the effects of forecasting errors in wind and insolation on load-matching and transmission line congestion.

Time-course of changes in neuronal activity markers following iTBS-TMS of the rat neocortex.

PubMed

Hoppenrath, Kathrin; Funke, Klaus

2013-03-01

In a rat model of transcranial magnetic stimulation we could recently show that intermittent theta-burst stimulation (iTBS) affects the neocortical expression of the immediate early gene products c-Fos and zif268 as well as that of the two glutamic acid decarboxylase isoforms GAD65 and GAD67 and that of the calcium-binding proteins calbindin (CB) and parvalbumin (PV), known as markers of excitatory and inhibitory activity. We now analyzed in more detail the time course of changes in the expression of these proteins at 10, 20, 40, 80 and 160min following a single block of iTBS consisting of 600 stimuli. Initial increase in c-Fos, zif268 and GAD65 (20min) signals transient activation of excitatory and inhibitory neurons, thereafter first followed by a decrease in markers of activity of inhibitory neurons (GAD67, PV, CB: 20-80min) and then by a late decrease in c-Fos and GAD65 expression (160min). The results demonstrate that one iTBS block may have an after-effect of at least two different phases, an early phase with increased neuronal activity (c-Fos, zif268) but also the likelihood of increased GABA-release (GAD65), followed by a late phase (>40min) of reduced neuronal activity in excitatory and inhibitory systems which may indicate a state of reduced excitability. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

[Nonnative guidelines for allocating human resources in child and adolescent psychiatry using average values under convergence conditions instead of price determination - analysis of the data of university hospitals in Germany concerning the costs of calculating day and minute values according to Psych-PV and PEPP-System].

PubMed

Barufka, Steffi; Heller, Michael; Prayon, Valeria; Fegert, Jörg M

2015-11-01

Despite substantial opposition in the practical field, based on an amendment to the Hospital Financing Act (KHG). the so-called PEPP-System was introduced in child and adolescent psychiatry as a new calculation model. The 2-year moratorium, combined with the rescheduling of the repeal of the psychiatry personnel regulation (Psych-PV) and a convergence phase, provided the German Federal Ministry of Health with additional time to enter a structured dialogue with professional associations. Especially the perspective concerning the regulatory framework is presently unclear. In light of this debate, this article provides calculations to illustrate the transformation of the previous personnel regulation into the PEPP-System by means of the data of §21 KHEntgG stemming from the 22 university hospitals of child and adolescent psychiatry and psychotherapy in Germany. In 2013 there was a total of 7,712 cases and 263,694 calculation days. In order to identify a necessary basic reimbursement value th1\\t would guarantee a constant quality of patient care, the authors utilize outcomes, cost structures, calculation days, and minute values for individual professional groups according to both systems (Psych-PV and PEPP) based on data from 2013 and the InEK' s analysis of the calculation datasets. The authors propose a normative agreement on the basic reimbursement value between 270 and 285 EUR. This takes into account the concentration phenomenon and the expansion of services that has occurred since the introduction of the Psych-PV system. Such a normative agreement on structural quality could provide a verifiable framework for the allocation of human resources corresponding to the previous regulations of Psych-PV.

Reliability and Geographic Trends of 50,000 Photovoltaic Systems in the USA: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, D. C.; Kurtz, S. R.

2014-09-01

This paper presents performance and reliability data from nearly 50,000 photovoltaic (PV) systems totaling 1.7 gigawatts installed capacity in the USA from 2009 to 2012 and their geographic trends. About 90% of the normal systems and about 85% of all systems, including systems with known issues, performed to within 10% or better of expected performance. Although considerable uncertainty may exist due to the nature of the data, hotter climates appear to exhibit some degradation not seen in the more moderate climates. Special causes of underperformance and their impacts are delineated by reliability category. Hardware-related issues are dominated by inverter problemsmore » (totaling less than 0.5%) and underperforming modules (totaling less than 0.1%). Furthermore, many reliability categories show a significant decrease in occurrence from year 1 to subsequent years, emphasizing the need for higher-quality installations but also the need for improved standards development. The probability of PV system damage because of hail is below 0.05%. Singular weather events can have a significant impact such as a single lightning strike to a transformer or the impact of a hurricane. However, grid outages are more likely to have a significant impact than PV system damage when extreme weather events occur.« less

Intermittent fasting promotes bacterial clearance and intestinal IgA production in Salmonella typhimurium-infected mice.

PubMed

Godínez-Victoria, M; Campos-Rodriguez, R; Rivera-Aguilar, V; Lara-Padilla, E; Pacheco-Yepez, J; Jarillo-Luna, R A; Drago-Serrano, M E

2014-05-01

The impact of intermittent fasting versus ad libitum feeding during Salmonella typhimurium infection was evaluated in terms of duodenum IgA levels, bacterial clearance and intestinal and extra-intestinal infection susceptibility. Mice that were intermittently fasted for 12 weeks or fed ad libitum were infected with S. typhimurium and assessed at 7 and 14 days post-infection. Next, we evaluated bacterial load in the faeces, Peyer's patches, spleen and liver by plate counting, as well as total and specific intestinal IgA and plasmatic corticosterone levels (by immunoenzymatic assay) and lamina propria IgA levels in plasma cells (by cytofluorometry). Polymeric immunoglobulin receptor, α- and J-chains, Pax-5 factor, pro-inflammatory cytokine (tumour necrosis factor-α and interferon-γ) and anti-inflammatory cytokine (transforming growth factor-β) mRNA levels were assessed in mucosal and liver samples (by real-time PCR). Compared with the infected ad libitum mice, the intermittently fasted infected animals had (1) lower intestinal and systemic bacterial loads; (2) higher SIgA and IgA plasma cell levels; (3) higher mRNA expression of most intestinal parameters; and (4) increased or decreased corticosterone levels on day 7 and 14 post-infection, respectively. No contribution of liver IgA was observed at the intestinal level. Apparently, the changes following metabolic stress induced by intermittent fasting during food deprivation days increased the resistance to S. typhimurium infection by triggering intestinal IgA production and presumably, pathogen elimination by phagocytic inflammatory cells. © 2014 John Wiley & Sons Ltd.

Intelligent Structured Intermittent Auscultation (ISIA): evaluation of a decision-making framework for fetal heart monitoring of low-risk women

PubMed Central

2014-01-01

Background Research-informed fetal monitoring guidelines recommend intermittent auscultation (IA) for fetal heart monitoring for low-risk women. However, the use of cardiotocography (CTG) continues to dominate many institutional maternity settings. Methods A mixed methods intervention study with before and after measurement was undertaken in one secondary level health service to facilitate the implementation of an initiative to encourage the use of IA. The intervention initiative was a decision-making framework called Intelligent Structured Intermittent Auscultation (ISIA) introduced through an education session. Results Following the intervention, medical records review revealed an increase in the use of IA during labour represented by a relative change of 12%, with improved documentation of clinical findings from assessments, and a significant reduction in the risk of receiving an admission CTG (RR 0.75, 95% CI, 0.60 – 0.95, p = 0.016). Conclusion The ISIA informed decision-making framework transformed the practice of IA and provided a mechanism for knowledge translation that enabled midwives to implement evidence-based fetal heart monitoring for low risk women. PMID:24884597

Characterization and consequences of intermittent sediment oxygenation by macrofauna: interpretation of high-resolution data sets

NASA Astrophysics Data System (ADS)

Meile, C. D.; Dwyer, I.; Zhu, Q.; Polerecky, L.; Volkenborn, N.

2017-12-01

Mineralization of organic matter in marine sediments leads to the depletion of oxygen, while activities of infauna introduce oxygenated seawater to the subsurface. In permeable sediments solutes can be transported from animals and their burrows into the surrounding sediment through advection over several centimeters. The intermittency of pumping leads to a spatially heterogeneous distribution of oxidants, with the temporal dynamics depending on sediment reactivity and activity patterns of the macrofauna. Here, we present results from a series of experiments in which these dynamics are studied at high spatial and temporal resolution using planar optodes. From O2, pH and pCO2 optode data, we quantify rates of O2 consumption and dissolved inorganic carbon production, as well alkalinity dynamics, with millimeter-scale resolution. Simulating intermittent irrigation by imposed pumping patterns in thin aquaria, we derive porewater flow patterns, which together with the production and consumption rates cause the chemical distributions and the establishment of reaction fronts. Our analysis thus establishes a quantitative connection between the locally dynamic redox conditions relevant for biogeochemical transformations and macroscopic observations commonly made with sediment cores.

Ship Vibration Design Guide

DTIC Science & Technology

1989-07-01

for further development are indicated. This guide addresses the major components over which we have the ability to excercise control in the design...this same period, very fast electronic analyzers also became available at a reasonable cost. Known as Fast Fourier Transform (FFT), these analyzers...An oscilloscope is desirable anyway to judge whether the signals look reasonable or not. Usually intermittent connections, 60 Hz noise, or other

Where to Turn for Second-Line Cytoreduction After Hydroxyurea in Polycythemia Vera?

PubMed

Nazha, Aziz; Gerds, Aaron T

2016-04-01

The goals of therapy in patients with polycythemia vera (PV) are to improve disease-related symptoms, prevent the incidence or recurrence of thrombosis, and possibly delay or prevent the transformation into myelofibrosis or acute myeloid leukemia (AML). Cytoreductive therapies have been used in older patients and those with a history of thrombosis to achieve these goals. Hydroxyurea (HU) remains the first-line cytoreductive choice; however, up to one in four patients treated with HU over time will develop resistance or intolerance to HU. More importantly, patients who fail HU have a 5.6-fold increase in mortality and a 6.8-fold increase risk of transformation to myelofibrosis or AML; therefore, alternative therapies are needed for these patients. Interferon-α has been used in PV and has shown significant activity in achieving hematologic responses and decreasing JAK2 V617F mutation allele burden. JAK inhibition has also been investigated and recently garnered regulatory approval for this indication. In this review, we will discuss the current treatment options that are available for patients after HU and the novel therapies that are currently under investigation. The outcomes of PV patients who fail or who are intolerant of hydroxyurea are poor. Although pegylated interferon can be considered in younger patients, currently, ruxolitinib is the only U.S. Food and Drug Administration-approved agent in this setting, representing a viable option, leading to hematocrit control and a reduction in spleen size and constitutional symptoms. Although a small number of patients will achieve a molecular response with continuous treatment, the implications of such response on the clinical outcomes are still unknown. Patients whose disease is not adequately controlled with ruxolitinib, or who lose their response, can be treated with low-dose busulfan or pipobroman; however, they should be encouraged to participate in trials with novel therapies. ©AlphaMed Press.

Clinical Features of 294 Turkish Patients with Chronic Myeloproliferative Neoplasms

PubMed Central

Andıç, Neslihan; Ünübol, Mustafa; Yağcı, Eren; Akay, Olga Meltem; Yavaşoğlu, İrfan; Kadıköylü, Vefki Gürhan; Bolaman, Ali Zahit

2016-01-01

Objective: Myeloproliferative neoplasms (MPNs) share common clonal stem cells but show significant differences in their clinical courses. The aim of this retrospective study was to evaluate thrombotic and hemorrhagic complications, JAK2 status, gastrointestinal and cardiac changes, treatment modalities, and survival in MPNs in Turkish patients. Materials and Methods: Medical files of 294 patients [112 essential thrombocythemia (ET), 117 polycythemia vera (PV), 46 primary myelofibrosis, and 19 unclassified MPN cases] from 2 different universities in Turkey were examined. Results: Older age, higher leukocyte count at diagnosis, and JAK2 mutation positivity were risk factors for thrombosis. Platelet count over 1000x109/L was a risk factor for hemorrhagic episodes. Hydroxyurea treatment was not related to leukemic transformation. Median follow-up time was 50 months (quartiles: 22.2-81.75) in these patients. Patients with primary myelofibrosis had the shortest survival of 137 months when compared with 179 months for ET and 231 months for PV. Leukemic transformation, thromboembolic events, age over 60 years, and anemia were found to be the factors affecting survival. Conclusion: Thromboembolic complications are the most important preventable risk factors for morbidity and mortality in MPNs. Drug management in MPNs is done according to hemoglobin and platelet counts. Based on the current study population our results support the idea that leukocytosis and JAK2 positivity are more important risk factors for thrombosis than hemoglobin and platelet values. PMID:27094255

Patient characteristics and outcomes in adolescents and young adults with classical Philadelphia chromosome-negative myeloproliferative neoplasms.

PubMed

Boddu, Prajwal; Masarova, Lucia; Verstovsek, Srdan; Strati, Paolo; Kantarjian, Hagop; Cortes, Jorge; Estrov, Zeev; Pierce, Sherry; Pemmaraju, Naveen

2018-01-01

Little is known about the outcomes of Philadelphia-negative myeloproliferative neoplasms (MPNs) in adolescents and young adults (AYA). We reviewed all patients with essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF) treated at our institution from 1988 to 2016 who were aged 16 to 39 years (AYA) and described their outcomes in comparison to older MPN population. Of 2206 patients, 185 (8.3%) were identified as AYA: 105 (57%) ET, 43 (23%) PV, and 37 (20%) MF. The median age was 33 years [range, 16-39], and median follow-up time 3 years [range, 0.04-25]. JAK2 allele burdens were significantly lower among AYA JAK2V617F-mutated patients in both PV (p = 0.001) and MF (p = 0.005). Seven percent of MPN AYA patients were diagnosed with a thrombotic event at, or prior to, diagnosis. Over the short median follow-up, 4 thrombotic (PV = 1, MF = 3) and 3 leukemia (ET = 2, MF = 1) events occurred. In multivariate analysis, AYA did not predict for thrombotic or transformational events across three cohorts. In the MF cohort, there was a reduced frequency of negative prognostic variables of anemia (p = 0.011) and leukocytosis (p = 0.048) in AYA when compared with non-AYA. Overall survival was significantly superior in the AYA cohorts in all three MPN groups, namely MF (p < 0.001), PV (p < 0.001), and ET (p = 0.002). Our findings suggest that MPN AYA patients exhibit an indolent clinical phenotype characterized by favorable survival outcomes.

Verapamil eliminates the hierarchical nature of activation frequencies from the pulmonary veins to the atria during paroxysmal atrial fibrillation.

PubMed

Kushiyama, Yasunori; Osaka, Toshiyuki; Yokoyama, Eriko; Hasebe, Hideyuki; Kuroda, Yusuke; Kamiya, Kaichiro; Kodama, Itsuo

2010-05-01

There is evidence that verapamil promotes the persistence of paroxysmal atrial fibrillation (AF). Little is known about the underlying mechanisms. The purpose of this study was to determine the effect of verapamil on dominant frequencies (DFs) in the pulmonary veins (PVs) and atria during paroxysmal AF with reference to its potential arrhythmogenicity. Forty-three patients with paroxysmal AF were studied. Bipolar electrograms were recorded simultaneously during AF from the right atrial free wall (RAFW), coronary sinus (CS) and three PVs, or two PVs and the left atrial appendage (LAA). The DFs were obtained by fast Fourier transform analysis before and after infusion of verapamil (0.1 mg/kg, intravenously). At baseline, the maximum DF among the PVs (6.9 +/- 0.9 Hz) was significantly higher than the DF in the RAFW (6.2 +/- 0.7 Hz), CS (5.7 +/- 0.5 Hz), or LAA (5.9 +/- 0.7 Hz) (P<.01); there was a substantial PV-to-atrial DF gradient (RAFW 0.7 +/- 0.9, CS 1.1 +/- 0.7, LAA 0.7 +/- 0.9 Hz). Verapamil increased the atrial DF to 6.9 +/- 0.8, 6.6 +/- 0.7, and 7.2 +/- 1.0 Hz in the RAFW, CS, and LAA, respectively (P<.0001) but did not affect the maximum PV DF (7.1 +/- 0.7 Hz). The PV-to-atrial DF gradient was eliminated after verapamil (RAFW 0.2 +/- 0.8, CS 0.5 +/- 0.6, LAA -0.4 +/- 0.8 Hz; P<.01 vs. baseline). Verapamil increases the activation frequency in the atria but not in the PVs, eliminating the PV-to-atrial DF gradient during paroxysmal AF. Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Fire resistant PV shingle assembly

DOEpatents

Lenox, Carl J.

2012-10-02

A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

Mechanisms of ammonium transformation and loss in intermittently aerated leachfield soil.

PubMed

Richard, John T; Potts, David A; Amador, José A

2014-11-01

Optimization of N removal in soil-based wastewater treatment systems requires an understanding of the microbial processes involved in N transformations. We examined the fate of NH in intermittently aerated leachfield mesocosms over a 24-h period. Septic tank effluent (STE) was amended with NHCl to help determine N speciation and distribution in drainage water, soil, and headspace gases. Our results show that 5.7% of the N was found in soil, 10.0% in drainage water, and 84.3% in the gas pool. Ammonium accounted for 41.7% of the soil N pool, followed by NO (29.2%), organic N (21.7%), and microbial biomass N (7.5%). In drainage water, NO constituted ∼80% of the N pool, whereas NH was absent from this pool. Nitrous oxide was the dominant form of N in the gas phase 6 h after addition of NH-amended STE to the mesocosms, after which its mass declined exponentially; by contrast, the mass of N was initially low but increased linearly with time to become the dominant form of N after 24 h. Analysis based on the isotopic enrichment of NO and N indicates that nitrification contributed 98.8 and 23.1% of the NO flux after 6 and 24 h, respectively. Our results show that gaseous losses are the main mechanism for NH removal from wastewater in intermittently aerated soil. In addition, nitrification, which is generally not considered a significant pathway for N loss in soil-based wastewater treatment, is an important source process for NO. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Intermittent PTH treatment can delay the transformation of mature osteoblasts into lining cells on the periosteal surfaces.

PubMed

Jang, Mi-Gyeong; Lee, Ji Yeon; Yang, Jae-Yeon; Park, Hyojung; Kim, Jung Hee; Kim, Jung-Eun; Shin, Chan Soo; Kim, Seong Yeon; Kim, Sang Wan

2016-09-01

Mature osteoblasts have three fates: as osteocytes, quiescent lining cells, or osteoblasts that undergo apoptosis. However, whether intermittent parathyroid hormone (PTH) can modulate the fate of mature osteoblasts in vivo is uncertain. We performed a lineage-tracing study using an inducible gene system. Dmp1-CreERt2 mice were crossed with Rosa26R reporter mice to obtain targeted mature osteoblasts and their descendants, lining cells or osteocytes, which were detected using X-gal staining. Rosa26R:Dmp1-CreERt2(+) mice were injected with 0.25 mg 4-OH-tamoxifen (4-OHTam) on postnatal days 5, 7, 9, 16, and 23. In a previous study, at 22 days after the last 4-OHTam, most LacZ+ cells on the periosteal surface were inactive lining cells. On day 25 (D25), the mice were challenged with an injection of human PTH (1-34, 80 μg/kg) or vehicle daily for 10 (D36) or 20 days (D46). We evaluated the number and thickness of LacZ+ osteoblast descendants in the calvaria and tibia. In the vehicle group, the number and thickness of LacZ+ osteoblast descendants at both D36 and D46 significantly decreased compared to D25, which was attenuated in the PTH group. In line with these results, PTH inhibited the decrease in the number of LacZ+/osteocalcin-positive cells compared to vehicle at both D36 and D46. As well, the serum levels of sclerostin decreased, as did the protein expression of sclerostin in the cortical bone. These results suggest that intermittent PTH treatment can increase the number of periosteal osteoblasts by preventing mature osteoblasts from transforming into lining cells in vivo.

CREE: Making the Switch

ScienceCinema

Grider, David; Palmer, John

2018-05-11

CREE, with the help of ARPA-E funding, has developed a Silicon Carbide (SIC) transistor which can be used to create solid state transformers capable of meeting the unique needs of the emerging smart grid. SIC transistors are different from common silicon computer chips in that they handle grid scale voltages with ease and their high frequency switching is well suited to the intermittent nature of renewable energy generation.

Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Ainsworth, Nathan

A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed studymore » could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.« less

Magnetic character of a large continental transform: an aeromagnetic survey of the Dead Sea Fault

USGS Publications Warehouse

ten Brink, Uri S.; Rybakov, Michael; Al-Zoubi, Abdallah S.; Rotstein, Yair

2007-01-01

New high-resolution airborne magnetic (HRAM) data along a 120-km-long section of the Dead Sea Transform in southern Jordan and Israel shed light on the shallow structure of the fault zone and on the kinematics of the plate boundary. Despite infrequent seismic activity and only intermittent surface exposure, the fault is delineated clearly on a map of the first vertical derivative of the magnetic intensity, indicating that the source of the magnetic anomaly is shallow. The fault is manifested by a 10–20 nT negative anomaly in areas where the fault cuts through magnetic basement and by a

Efficiency of use endobronchial laser doppler-flowmetry in patients with chronic leukemia

NASA Astrophysics Data System (ADS)

Vanina, E. A.; Voitsekhovskiy, V. V.; Landyshev, Y. S.; Tkacheva, S. I.

2016-11-01

In this work indicatorsendobronchial microcirculation were investigated in patients with chronic myeloid leukemia (CML), chronic lymphocytic leukemia (CLL), multiple myeloma (MM), polycythemia vera (PV), idiopathic myelofibrosis (IMF). A diagnostic bronchoscopy was performed using fibreoptic «Olympus» (Japan).Endobronchial laser Doppler flowmetry was carried out on the laser analyzer capillary blood LAK-02 (Russia). Laser Doppler flowmetry indicators such as parameter of microcirculation, the oscillation amplitude in the endothelial, neurogenic, myogenic, cardiac and respiratory ranges were calculated by continuous the Wavelet transforms. Reduced cardiac and respiratory amplitudes in CML and CLL are primarily due to the development leukostasis. If PV is the case, this is due to sludge syndrome. And when MM occurs, it is caused by protein stasis in the vessels of the bronchial tubes. Increased endothelial oscillation amplitudes in the range in CML, PV, IMF and their reduction in MM indicate the presence of endothelial dysfunction in these patients. Increasing the amplitude of oscillations in the range of neurogenic indicates the development of arteriolar vasodilation as a compensatory response to the violation of blood flow. Increasing the amplitude of oscillations of myogenic tone indicating decrease precapillaries as a compensatory reaction to improve blood flow. It is concluded that endobronchial laser Doppler flowmetry is an important method allowing diagnosing the pathology of the microvasculature of the bronchi in chronic leukemia.

Classification of pregnancy and labor contractions using a graph theory based analysis.

PubMed

Nader, N; Hassan, M; Falou, W; Diab, A; Al-Omar, S; Khalil, M; Marque, C

2015-08-01

In this paper, we propose a new framework to characterize the electrohysterographic (EHG) signals recorded during pregnancy and labor. The approach is based on the analysis of the propagation of the uterine electrical activity. The processing pipeline includes i) the estimation of the statistical dependencies between the different recorded EHG signals, ii) the characterization of the obtained connectivity matrices using network measures and iii) the use of these measures in clinical application: the classification between pregnancy and labor. Due to its robustness to volume conductor, we used the imaginary part of coherence in order to produce the connectivity matrix which is then transformed into a graph. We evaluate the performance of several graph measures. We also compare the results with the parameter mostly used in the literature: the peak frequency combined with the propagation velocity (PV +PF). Our results show that the use of the network measures is a promising tool to classify labor and pregnancy contractions with a small superiority of the graph strength over PV+PF.

Characterization, antioxidant and immunomodulatory activities of polysaccharides from Prunella vulgaris Linn.

PubMed

Li, Chao; Huang, Qiang; Fu, Xiong; Yue, Xiu-Jie; Liu, Rui Hai; You, Li-Jun

2015-04-01

Water-soluble polysaccharides from Prunella vulgaris Linn (P. vulgaris) were fractionated using DEAE-Sepharose fast-flow column to obtain several eluents of water (PV-P1), 0.1M NaCl (PV-P2) and 0.2M NaCl (PV-P3). Structural analyses showed that PV-P1 had a higher molecular weight and degree of branching as compared to PV-P2 and PV-P3. Tertiary structure analyses indicated that PV-P1, PV-P2 and PV-P3 did not have triple-helical conformation. PV-P2 and PV-P3 showed stronger antioxidant activities than PV-P1, as measured radical scavenging capacities. PV-P1 showed stronger immunomodulatory activities than PV-P2 and PV-P3 in term of stimulation of the production of pro-inflammatory cytokines, including nitric oxide (NO), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in murine macrophage RAW 264.7 cells. PV-P1, PV-P2 and PV-P3 did not exhibit cytotoxicities against RAW 264.7 at the concentrations tested. These results suggest that P. vulgaris polysaccharides could be explored as potential antioxidant and immunomodulatory agents for the complementary medicine or functional foods. Copyright © 2015 Elsevier B.V. All rights reserved.

Removing Barriers for Effective Deployment of Intermittent Renewable Generation

NASA Astrophysics Data System (ADS)

Arabali, Amirsaman

The stochastic nature of intermittent renewable resources is the main barrier to effective integration of renewable generation. This problem can be studied from feeder-scale and grid-scale perspectives. Two new stochastic methods are proposed to meet the feeder-scale controllable load with a hybrid renewable generation (including wind and PV) and energy storage system. For the first method, an optimization problem is developed whose objective function is the cost of the hybrid system including the cost of renewable generation and storage subject to constraints on energy storage and shifted load. A smart-grid strategy is developed to shift the load and match the renewable energy generation and controllable load. Minimizing the cost function guarantees minimum PV and wind generation installation, as well as storage capacity selection for supplying the controllable load. A confidence coefficient is allocated to each stochastic constraint which shows to what degree the constraint is satisfied. In the second method, a stochastic framework is developed for optimal sizing and reliability analysis of a hybrid power system including renewable resources (PV and wind) and energy storage system. The hybrid power system is optimally sized to satisfy the controllable load with a specified reliability level. A load-shifting strategy is added to provide more flexibility for the system and decrease the installation cost. Load shifting strategies and their potential impacts on the hybrid system reliability/cost analysis are evaluated trough different scenarios. Using a compromise-solution method, the best compromise between the reliability and cost will be realized for the hybrid system. For the second problem, a grid-scale stochastic framework is developed to examine the storage application and its optimal placement for the social cost and transmission congestion relief of wind integration. Storage systems are optimally placed and adequately sized to minimize the sum of operation and congestion costs over a scheduling period. A technical assessment framework is developed to enhance the efficiency of wind integration and evaluate the economics of storage technologies and conventional gas-fired alternatives. The proposed method is used to carry out a cost-benefit analysis for the IEEE 24-bus system and determine the most economical technology. In order to mitigate the financial and technical concerns of renewable energy integration into the power system, a stochastic framework is proposed for transmission grid reinforcement studies in a power system with wind generation. A multi-stage multi-objective transmission network expansion planning (TNEP) methodology is developed which considers the investment cost, absorption of private investment and reliability of the system as the objective functions. A Non-dominated Sorting Genetic Algorithm (NSGA II) optimization approach is used in combination with a probabilistic optimal power flow (POPF) to determine the Pareto optimal solutions considering the power system uncertainties. Using a compromise-solution method, the best final plan is then realized based on the decision maker preferences. The proposed methodology is applied to the IEEE 24-bus Reliability Tests System (RTS) to evaluate the feasibility and practicality of the developed planning strategy.

Solarize Guidebook: A Community Guide to Collective Purchasing of Residential PV Systems (Book)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2012-05-01

This guidebook is intended as a road map for project planners and solar advocates who want to convert 'interest' into 'action,' to break through market barriers and permanently transform the market for residential solar installations in their communities. It describes the key elements of the Solarize campaigns in Portland, and offers several program refinements from projects beyond Portland. The guidebook provides lessons, considerations, and step-by-step plans for project organizers to replicate the success of Solarize Portland.

Mechanical Force-induced TGFB1 Increases Expression of SOST/POSTN by hPDL Cells.

PubMed

Manokawinchoke, J; Limjeerajarus, N; Limjeerajarus, C; Sastravaha, P; Everts, V; Pavasant, P

2015-07-01

The aim of this study was to investigate the response of human periodontal ligament (hPDL) fibroblasts to an intermittent compressive force and its effect on the expression of SOST, POSTN, and TGFB1. A computerized cell compressive force loading apparatus was introduced, and hPDL cells were subjected to intermittent compressive force. The changes in messenger RNA (mRNA) and protein expression were monitored by real-time polymerase chain reaction and Western blot analysis, respectively. An increased expression of SOST, POSTN, and TGFB1 was observed in a time-dependent fashion. Addition of cycloheximide, a transforming growth factor (TGF)-β inhibitor (SB431542), or a neutralizing antibody against TGF-β1 attenuated the force-induced expression of SOST and POSTN as well as sclerostin and periostin, indicating a role of TGF-β1 in the pressure-induced expression of these proteins. Enzyme-linked immunosorbent assay analysis revealed an increased level of TGF-β1 in the cell extracts but not in the medium, suggesting that intermittent compressive force promoted the accumulation of TGF-β1 in the cells or their surrounding matrix. In conclusion, an intermittent compressive force regulates SOST/POSTN expression by hPDL cells via the TGF-β1 signaling pathway. Since these proteins play important roles in the homeostasis of the periodontal tissue, our results indicate the importance of masticatory forces in this process. © International & American Associations for Dental Research 2015.

Higher order statistical moment application for solar PV potential analysis

NASA Astrophysics Data System (ADS)

Basri, Mohd Juhari Mat; Abdullah, Samizee; Azrulhisham, Engku Ahmad; Harun, Khairulezuan

2016-10-01

Solar photovoltaic energy could be as alternative energy to fossil fuel, which is depleting and posing a global warming problem. However, this renewable energy is so variable and intermittent to be relied on. Therefore the knowledge of energy potential is very important for any site to build this solar photovoltaic power generation system. Here, the application of higher order statistical moment model is being analyzed using data collected from 5MW grid-connected photovoltaic system. Due to the dynamic changes of skewness and kurtosis of AC power and solar irradiance distributions of the solar farm, Pearson system where the probability distribution is calculated by matching their theoretical moments with that of the empirical moments of a distribution could be suitable for this purpose. On the advantage of the Pearson system in MATLAB, a software programming has been developed to help in data processing for distribution fitting and potential analysis for future projection of amount of AC power and solar irradiance availability.

Supported PV module assembly

DOEpatents

Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

2013-10-15

A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

Pressure-equalizing PV assembly and method

DOEpatents

Dinwoodie, Thomas L.

2004-10-26

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

Performance comparison investigation on solar photovoltaic-thermoelectric generation and solar photovoltaic-thermoelectric cooling hybrid systems under different conditions

NASA Astrophysics Data System (ADS)

Wu, Shuang-Ying; Zhang, Yi-Chen; Xiao, Lan; Shen, Zu-Guo

2018-07-01

The performance of solar photovoltaic-thermoelectric generation hybrid system (PV-TGS) and solar photovoltaic-thermoelectric cooling hybrid system (PV-TCS) under different conditions were theoretically analysed and compared. To test the practicality of these two hybrid systems, the performance of stand-alone PV system was also studied. The results show that PV-TGS and PV-TCS in most cases will result in the system with a better performance than stand-alone PV system. The advantage of PV-TGS is emphasised in total output power and conversion efficiency which is even poorer in PV-TCS than that in stand-alone PV system at the ambient wind speed uw being below 3 m/s. However, PV-TCS has obvious advantage on lowering the temperature of PV cell. There is an obvious increase in tendency on the performance of PV-TGS and PV-TCS when the cooling capacity of two hybrid systems varies from around 0.06 to 0.3 W/K. And it is also proved that not just a-Si in PV-TGS can produce a better performance than the stand-alone PV system alone at most cases.

Molecular characterization of novel mucosotropic papillomaviruses from a Florida manatee (Trichechus manatus latirostris).

PubMed

2015-12-01

We isolated two new manatee papillomavirus (PV) types, TmPV3 and TmPV4, from a Florida manatee (Trichechus manatus latirostris). Two PV types were previously isolated from this species. TmPV1 is widely dispersed amongst manatees and a close-to-root PV; not much is known about TmPV2. The genomes of TmPV3 and TmPV4 were 7622 and 7771 bp in size, respectively. Both PVs had a genomic organization characteristic of all PVs, with one non-coding region and seven ORFs, including the E7 ORF that is absent in other cetacean PVs. Although these PVs were isolated from separate genital lesions of the same manatee, an enlarged E2/E4 ORF was found only in the TmPV4 genome. The full genome and L1 sequence similarities between TmPV3 and TmPV4 were 63.2 and 70.3 %, respectively. These genomes shared only 49.1 and 50.2 % similarity with TmPV1. The pairwise alignment of L1 nucleotide sequences indicated that the two new PVs nested in a monophyletic group of the genus Rhopapillomavirus, together with the cutaneotropic TmPV1 and TmPV2.

Silicon Materials and Devices R&D | Photovoltaic Research | NREL

Science.gov Websites

" and "Si-based Tandem Solar Cells"), Next Generation Photovoltaics (NextGen PV III), and devices, especially for photovoltaic (PV) cell applications. PV Research Other Materials & Devices pages: High-Efficiency Crystalline PV Polycrystalline Thin-Film PV Perovskite and Organic PV Advanced PV

Rational classification of portal vein thrombosis and its clinical significance.

PubMed

Ma, Jingqin; Yan, Zhiping; Luo, Jianjun; Liu, Qingxin; Wang, Jianhua; Qiu, Shijing

2014-01-01

Portal vein thrombosis (PVT) is commonly classified into acute (symptom duration <60 days and absence of portal carvernoma and portal hypertension) and chronic types. However, the rationality of this classification has received little attention. In this study, 60 patients (40 men and 20 women) with PVT were examined using contrast-enhanced computed tomography (CT). The percentage of vein occlusion, including portal vein (PV) and superior mesenteric vein (SMV), was measured on CT image. Of 60 patients, 17 (28.3%) met the criterion of acute PVT. Symptoms occurred more frequently in patients with superior mesenteric vein thrombosis (SMVT) compared to those without SMVT (p<0.001). However, there was no significant difference in PV occlusion between patients with and without symptoms. The frequency of cavernous transformation was significantly higher in patients with complete PVT than those with partial PVT (p<0.001). Complications of portal hypertension were significantly associated with cirrhosis (p<0.001) rather than with the severity of PVT and presence of cavernoma. These results suggest that the severity of PVT is only associated with the formation of portal cavernoma but unrelated to the onset of symptoms and the development of portal hypertension. We classified PVT into complete and partial types, and each was subclassified into with and without portal cavernoma. In conclusion, neither symptom duration nor cavernous transformation can clearly distinguish between acute and chronic PVT. The new classification system can determine the pathological alterations of PVT, patency of portal vein and outcome of treatment in a longitudinal study.

Rational Classification of Portal Vein Thrombosis and Its Clinical Significance

PubMed Central

Ma, Jingqin; Yan, Zhiping; Luo, Jianjun; Liu, Qingxin; Wang, Jianhua; Qiu, Shijing

2014-01-01

Portal vein thrombosis (PVT) is commonly classified into acute (symptom duration <60 days and absence of portal carvernoma and portal hypertension) and chronic types. However, the rationality of this classification has received little attention. In this study, 60 patients (40 men and 20 women) with PVT were examined using contrast-enhanced computed tomography (CT). The percentage of vein occlusion, including portal vein (PV) and superior mesenteric vein (SMV), was measured on CT image. Of 60 patients, 17 (28.3%) met the criterion of acute PVT. Symptoms occurred more frequently in patients with superior mesenteric vein thrombosis (SMVT) compared to those without SMVT (p<0.001). However, there was no significant difference in PV occlusion between patients with and without symptoms. The frequency of cavernous transformation was significantly higher in patients with complete PVT than those with partial PVT (p<0.001). Complications of portal hypertension were significantly associated with cirrhosis (p<0.001) rather than with the severity of PVT and presence of cavernoma. These results suggest that the severity of PVT is only associated with the formation of portal cavernoma but unrelated to the onset of symptoms and the development of portal hypertension. We classified PVT into complete and partial types, and each was subclassified into with and without portal cavernoma. In conclusion, neither symptom duration nor cavernous transformation can clearly distinguish between acute and chronic PVT. The new classification system can determine the pathological alterations of PVT, patency of portal vein and outcome of treatment in a longitudinal study. PMID:25393320

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

The possibility of developing hybrid PV/T solar system

NASA Astrophysics Data System (ADS)

Dobrnjac, M.; Zivkovic, P.; Babic, V.

2017-05-01

An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

Developing High PV Penetration Cases for Frequency Response Study of U.S. Western Interconnection: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Jin; Zhang, Yingchen; Veda, Santosh

2017-04-11

Recent large penetrations of solar photovoltaic (PV) generation and the inertial characteristics of inverter-based generation technologies have caught the attention of those in the electric power industry in the United States. This paper presents a systematic approach to developing test cases of high penetrations of PV for the Western Interconnection. First, to examine the accuracy of the base case model, the Western Electricity Coordinating Council (WECC) model is validated by using measurement data from synchronized phasor measurement units. Based on the 2022 Light Spring case, we developed four high PV penetration cases for the WECC system that are of interestmore » to the industry: 5% PV+15 % wind, 25% PV+15% wind, 45% PV+15% wind, 65% PV+15% wind). Additionally, a method to project PV is proposed that is based on collected, realistic PV distribution information, including the current and future PV power plant locations and penetrations in the WECC system. Both the utility-scale PV plant and residential rooftop PV are included in this study.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grocholski, Brent; Catalli, Krystle; Shim, Sang-Heon

The discovery of a phase transition in Mg-silicate perovskite (Pv) to postperovskite (pPv) at lowermost mantle pressure-temperature (P - T) conditions may provide an explanation for the discontinuous increase in shear wave velocity found in some regions at a depth range of 200 to 400 km above the core-mantle boundary, hereafter the D{double_prime} discontinuity. However, recent studies on binary and ternary systems showed that reasonable contents of Fe{sup 2+} and Al for pyrolite increase the thickness (width of the mixed phase region) of the Pv - pPv boundary (400-600 km) to much larger than the D{double_prime} discontinuity ({le} 70 km).more » These results challenge the assignment of the D{double_prime} discontinuity to the Pv - pPv boundary in pyrolite (homogenized mantle composition). Furthermore, the mineralogy and composition of rocks that can host a detectable Pv {yields} pPv boundary are still unknown. Here we report in situ measurements of the depths and thicknesses of the Pv {yields} pPv transition in multiphase systems (San Carlos olivine, pyrolitic, and midocean ridge basaltic compositions) at the P - T conditions of the lowermost mantle, searching for candidate rocks with a sharp Pv - pPv discontinuity. Whereas the pyrolitic mantle may not have a seismologically detectable Pv {yields} pPv transition due to the effect of Al, harzburgitic compositions have detectable transitions due to low Al content. In contrast, Al-rich basaltic compositions may have a detectable Pv - pPv boundary due to their distinct mineralogy. Therefore, the observation of the D{prime} discontinuity may be related to the Pv {yields} pPv transition in the differentiated oceanic lithosphere materials transported to the lowermost mantle by subducting slabs.« less

Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulvestad, A.; Welland, M. J.; Collins, S. S. E.

2015-12-11

Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/ discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surfacemore » layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. In conclusion, our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments.« less

Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles

NASA Astrophysics Data System (ADS)

Ulvestad, A.; Welland, M. J.; Collins, S. S. E.; Harder, R.; Maxey, E.; Wingert, J.; Singer, A.; Hy, S.; Mulvaney, P.; Zapol, P.; Shpyrko, O. G.

2015-12-01

Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surface layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. Our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments.

Avalanching strain dynamics during the hydriding phase transformation in individual palladium nanoparticles

PubMed Central

Ulvestad, A.; Welland, M. J.; Collins, S. S. E.; Harder, R.; Maxey, E.; Wingert, J.; Singer, A.; Hy, S.; Mulvaney, P.; Zapol, P.; Shpyrko, O. G.

2015-01-01

Phase transitions in reactive environments are crucially important in energy and information storage, catalysis and sensors. Nanostructuring active particles can yield faster charging/discharging kinetics, increased lifespan and record catalytic activities. However, establishing the causal link between structure and function is challenging for nanoparticles, as ensemble measurements convolve intrinsic single-particle properties with sample diversity. Here we study the hydriding phase transformation in individual palladium nanocubes in situ using coherent X-ray diffractive imaging. The phase transformation dynamics, which involve the nucleation and propagation of a hydrogen-rich region, are dependent on absolute time (aging) and involve intermittent dynamics (avalanching). A hydrogen-rich surface layer dominates the crystal strain in the hydrogen-poor phase, while strain inversion occurs at the cube corners in the hydrogen-rich phase. A three-dimensional phase-field model is used to interpret the experimental results. Our experimental and theoretical approach provides a general framework for designing and optimizing phase transformations for single nanocrystals in reactive environments. PMID:26655832

PV module mounting method and mounting assembly

DOEpatents

Lenox, Carl J.S.; Johnson, Kurt M.

2013-04-23

A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

Utility-Scale Solar Power Converter: Agile Direct Grid Connect Medium Voltage 4.7-13.8 kV Power Converter for PV Applications Utilizing Wide Band Gap Devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Solar ADEPT Project: Satcon is developing a compact, lightweight power conversion device that is capable of taking utility-scale solar power and outputting it directly into the electric utility grid at distribution voltage levels—eliminating the need for large transformers. Transformers “step up” the voltage of the power that is generated by a solar power system so it can be efficiently transported through transmission lines and eventually “stepped down” to usable voltages before it enters homes and businesses. Power companies step up the voltage because less electricity is lost along transmission lines when the voltage is high and current is low. Satcon’smore » new power conversion devices will eliminate these heavy transformers and connect a utility-scale solar power system directly to the grid. Satcon’s modular devices are designed to ensure reliability—if one device fails it can be bypassed and the system can continue to run.« less

Proposed MIL Standard and Handbook - Flying Qualities of Air Vehicles. Volume 2. Proposed MIL Handbook

DTIC Science & Technology

1982-11-01

model but uses the Hilbert transform to model intermittency as well as Gaussian structure patchiness. Includes University of Washington model features...Requirements for Satisfactory Elevator Control Characteristics, NACA TN 1060, June 1946. 852 - - - - 137. Jones, R. T., and H. Greenberg , Effect of Hinge...Moment Parameters on Elevator Stick Forces in Rapid Maneuvers NACA Report 798, Nov. 1944. 138. Greenberg , H., and L. Sternfield, A Theoretical

Photovoltaic (PV) Systems Comparison at Fort Hood

DTIC Science & Technology

2010-06-01

Monocrystalline PV panels • Energy Photovoltaics, EPV-42 Solar Modules: Thin film PV panels • OutBack Flexware PV Advanced Photovoltaic Combiner...energy for an administrative building – Compare the performance between two different PV technologies: thin film and crystalline PV panels • Demo Team...Center for Energy and Environment PV Technology • Monocrystalline silicon1 • Thin film2 1 “About Solar,” DBK Corporation, http://www.dbksolar.com

Pressure equalizing photovoltaic assembly and method

DOEpatents

Dinwoodie, Thomas L [Piedmont, CA

2003-05-27

Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the peripheral edge of the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

Noncontact on-machine measurement system based on capacitive displacement sensors for single-point diamond turning

NASA Astrophysics Data System (ADS)

Li, Xingchang; Zhang, Zhiyu; Hu, Haifei; Li, Yingjie; Xiong, Ling; Zhang, Xuejun; Yan, Jiwang

2018-04-01

On-machine measurements can improve the form accuracy of optical surfaces in single-point diamond turning applications; however, commercially available linear variable differential transformer sensors are inaccurate and can potentially scratch the surface. We present an on-machine measurement system based on capacitive displacement sensors for high-precision optical surfaces. In the proposed system, a position-trigger method of measurement was developed to ensure strict correspondence between the measurement points and the measurement data with no intervening time-delay. In addition, a double-sensor measurement was proposed to reduce the electric signal noise during spindle rotation. Using the proposed system, the repeatability of 80-nm peak-to-valley (PV) and 8-nm root-mean-square (RMS) was achieved through analyzing four successive measurement results. The accuracy of 109-nm PV and 14-nm RMS was obtained by comparing with the interferometer measurement result. An aluminum spherical mirror with a diameter of 300 mm was fabricated, and the resulting measured form error after one compensation cut was decreased to 254 nm in PV and 52 nm in RMS. These results confirm that the measurements of the surface form errors were successfully used to modify the cutting tool path during the compensation cut, thereby ensuring that the diamond turning process was more deterministic. In addition, the results show that the noise level was significantly reduced with the reference sensor even under a high rotational speed.

Novel papillomavirus isolated from the oral mucosa of a polar bear does not cluster with other papillomaviruses of carnivores.

PubMed

Stevens, Hans; Rector, Annabel; Bertelsen, Mads F; Leifsson, Pall S; Van Ranst, Marc

2008-05-25

Papillomatosis has been documented in several carnivores, and papillomavirus (PV) types have been characterized from lesions in a number of carnivore species: the canine oral PV (COPV), the Felis domesticus PV type 1 (FdPV-1) isolated from a Persian cat, the Procyon lotor PV type 1 (PlPV-1) isolated from a raccoon, the canine PV type 2 (CPV-2) from a dog's foot pad lesion and the canine PV type 3 (CPV-3) associated with a canine epidermodysplasia verruciformis - like disease. A tissue sample was taken from a papillomatous lesion on the oral mucosa of a polar bear (Ursus maritimus). Extracted DNA was used as a template for multiply primed rolling-circle amplification (RCA), and restriction enzyme analysis of the RCA product indicated the presence of papillomaviral DNA. The genome of this PV was cloned and the complete genomic sequence was determined. The Ursus maritimus PV type 1 (UmPV-1) genome counts 7582 basepairs and is smaller than that of other papillomaviruses from carnivore species. UmPV-1 contains the typical noncoding region NCR1, but unlike the carnivore PVs of the Lambda genus, UmPV-1 does not possess a second noncoding region NCR2. Phylogenetic analysis based on a nucleotide sequence alignment of the L1 ORF of UmPV-1 and 51 other PV types indicates that UmPV-1 does not cluster with any of the other carnivore PVs, but branches off near the root of the common branch of the genus Alphapapillomavirus.

Implementation of optimum solar electricity generating system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Balbir Singh Mahinder, E-mail: balbir@petronas.com.my; Karim, Samsul Ariffin A., E-mail: samsul-ariffin@petronas.com.my; Sivapalan, Subarna, E-mail: subarna-sivapalan@petronas.com.my

2014-10-24

Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness onmore » the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.« less

Physiological and performance responses to a training camp in the heat in professional Australian football players.

PubMed

Racinais, Sebastien; Buchheit, Martin; Bilsborough, Johann; Bourdon, Pitre C; Cordy, Justin; Coutts, Aaron J

2014-07-01

To examine the physiological and performance responses to a heat-acclimatization camp in highly trained professional team-sport athletes. Eighteen male Australian Rules Football players trained for 2 wk in hot ambient conditions (31-33°C, humidity 34-50%). Players performed a laboratory-based heat-response test (24-min walk + 24 min seated; 44°C), a YoYo Intermittent Recovery Level 2 Test (YoYoIR2; indoor, temperate environment, 23°C) and standardized training drills (STD; outdoor, hot environment, 32°C) at the beginning and end of the camp. The heat-response test showed partial heat acclimatization (eg, a decrease in skin temperature, heart rate, and sweat sodium concentration, P < .05). In addition, plasma volume (PV, CO rebreathing, +2.68 [0.83; 4.53] mL/kg) and distance covered during both the YoYoIR2 (+311 [260; 361] m) and the STD (+45.6 [13.9; 77.4] m) increased postcamp (P < .01). None of the performance changes showed clear correlations with PV changes (r < .24), but the improvements in running STD distance in hot environment were correlated with changes in hematocrit during the heat-response test (r = -.52, 90%CI [-.77; -.12]). There was no clear correlation between the performance improvements in temperate and hot ambient conditions (r < .26). Running performance in both hot and temperate environments was improved after a football training camp in hot ambient conditions that stimulated heat acclimatization. However, physiological and performance responses were highly individual, and the absence of correlations between physical-performance improvements in hot and temperate environments suggests that their physiological basis might differ.

Active mechanical stabilization of the viscoplastic intracellular space of Dictyostelia cells by microtubule-actin crosstalk.

PubMed

Heinrich, Doris; Sackmann, Erich

2006-11-01

The micro-viscoelasticity of the intracellular space of Dictyostelium discoideum cells is studied by evaluating the intracellular transport of magnetic force probes and their viscoelastic responses to force pulses of 20-700 pN. The role of the actin cortex, the microtubule (MT) aster and their crosstalk is explored by comparing the behaviour of wild-type cells, myosin II null mutants, latrunculin A and benomyl treated cells. The MT coupled beads perform irregular local and long range directed motions which are characterized by measuring their velocity distributions (P(v)). The correlated motion of the MT and the centrosome are evaluated by microfluorescence of GFP-labelled MTs. P(v) can be represented by log-normal distributions with long tails and it is determined by random sweeping motions (v approximately 0.5 microm/s) of the MTs (caused by tangential forces on the filament ends coupled to the actin cortex) and by intermittent bead transports parallel to the MTs (v(max) approximately 1.5 microm/s). The tails are due to spontaneous filament deflections (with speeds up to 10 microm/s) attributed to pre-stressing of the MT by local cortical tensions, generated by dynactin motors generating plus-end directed forces in the MTs. The viscoelastic responses are strongly non-linear and are mostly directed opposite or perpendicular to the force, showing that the cytoplasm behaves as an active viscoplastic body with time and force dependent drag coefficients. Nano-Newton loads exerted on the soft MT are balanced by traction forces arising at the MT ends coupled to the actin cortex and the centrosome, respectively. The mechanical coupling between the soft microtubules and the viscoelastic actin cortex provides cells with high mechanical stability despite the softness of the cytoplasm.

Implementation of optimum solar electricity generating system

NASA Astrophysics Data System (ADS)

Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

2014-10-01

Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

PV Calibration Insights | NREL

Science.gov Websites

PV Calibration Insights PV Calibration Insights The Photovoltaic (PV) Calibration Insights blog will provide updates on the testing done by the NREL PV Device Performance group. This NREL research group measures the performance of any and all technologies and sizes of PV devices from around the world

City and County Solar PV Training Program, Module 2: Screening and Identifying PV Projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elgqvist, Emma M

When screening and identifying PV projects, cities and counties should understand the different factors that impact the technical and economic potential of a PV project, the steps of the PV screening process, and how to use REopt Lite to screen a site for PV and storage project potential.

Ballasted photovoltaic module and module arrays

DOEpatents

Botkin, Jonathan [El Cerrito, CA; Graves, Simon [Berkeley, CA; Danning, Matt [Oakland, CA

2011-11-29

A photovoltaic (PV) module assembly including a PV module and a ballast tray. The PV module includes a PV device and a frame. A PV laminate is assembled to the frame, and the frame includes an arm. The ballast tray is adapted for containing ballast and is removably associated with the PV module in a ballasting state where the tray is vertically under the PV laminate and vertically over the arm to impede overt displacement of the PV module. The PV module assembly can be installed to a flat commercial rooftop, with the PV module and the ballast tray both resting upon the rooftop. In some embodiments, the ballasting state includes corresponding surfaces of the arm and the tray being spaced from one another under normal (low or no wind) conditions, such that the frame is not continuously subjected to a weight of the tray.

NREL’s Controllable Grid Interface Saves Time and Resources, Improves Reliability of Renewable Energy Technologies; NREL (National Renewable Energy Laboratory)

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

The National Renewable Energy Laboratory's (NREL) controllable grid interface (CGI) test system at the National Wind Technology Center (NWTC) is one of two user facilities at NREL capable of testing and analyzing the integration of megawatt-scale renewable energy systems. The CGI specializes in testing of multimegawatt-scale wind and photovoltaic (PV) technologies as well as energy storage devices, transformers, control and protection equipment at medium-voltage levels, allowing the determination of the grid impacts of the tested technology.

Design and Performance of the Hyper-Cam, an Infrared Hyperspectral Imaging Sensor

DTIC Science & Technology

2009-10-01

helps to reduce the noise level, since the FIRST is shot noise limited . 800 850 900 950 1000 1050 1100 1150 1200 1250 1300 1350 200 250 300 350 ab s( O...performed using a Fourier-Transform Spectrometer (FTS). It uses a 320x256 LWIR PV- MCT focal plane array detector that can be windowed and formatted...cooled down to 68 K. The offset is very low (~215 K), which indicates that the shot noise coming from the instrument radiance is minimized. This

Photovoltaic energy program overview, fiscal year 1991

NASA Astrophysics Data System (ADS)

1992-02-01

The Photovoltaics Program Plan, FY 1991 to FY 1995 builds on the accomplishments of the past 5 years and broadens the scope of program activities for the future. The previous plan emphasized materials and PV cell research. Under the balanced new plan, the PV Program continues its commitment to strategic research and development (R&D) into PV materials and processes, while also beginning work on PV systems and helping the PV industry encourage new markets for photovoltaics. A major challenge for the program is to assist the US PV industry in laying the foundation for at least 1000 MW of installed PV capacity in the United States and 500 MW internationally by 2000. As part of the new plan, the program expanded the scope of its activities in 1991. The PV Program is now addressing many new aspects of developing and commercializing photovoltaics. It is expanding activities with the US PV industry through the PV Manufacturing Technology (PVMaT) project, designed to address US manufacturers' immediate problems; providing technical assistance to potential end users such as electric utilities; and the program is turning its attention to encouraging new markets for PV. In 1991, for example, the PV Program initiated a new project with the PV industry to encourage a domestic market for PV applications in buildings and began cooperative ventures to support other countries such as Mexico to use PV in their rural electrification programs. This report reviews some of the development, fabrication and manufacturing advances in photovoltaics this year.

Identification and characterization of functional centromeres of the common bean.

PubMed

Iwata, Aiko; Tek, Ahmet L; Richard, Manon M S; Abernathy, Brian; Fonsêca, Artur; Schmutz, Jeremy; Chen, Nicolas W G; Thareau, Vincent; Magdelenat, Ghislaine; Li, Yupeng; Murata, Minoru; Pedrosa-Harand, Andrea; Geffroy, Valérie; Nagaki, Kiyotaka; Jackson, Scott A

2013-10-01

In higher eukaryotes, centromeres are typically composed of megabase-sized arrays of satellite repeats that evolve rapidly and homogenize within a species' genome. Despite the importance of centromeres, our knowledge is limited to a few model species. We conducted a comprehensive analysis of common bean (Phaseolus vulgaris) centromeric satellite DNA using genomic data, fluorescence in situ hybridization (FISH), immunofluorescence and chromatin immunoprecipitation (ChIP). Two unrelated centromere-specific satellite repeats, CentPv1 and CentPv2, and the common bean centromere-specific histone H3 (PvCENH3) were identified. FISH showed that CentPv1 and CentPv2 are predominantly located at subsets of eight and three centromeres, respectively. Immunofluorescence- and ChIP-based assays demonstrated the functional significance of CentPv1 and CentPv2 at centromeres. Genomic analysis revealed several interesting features of CentPv1 and CentPv2: (i) CentPv1 is organized into an higher-order repeat structure, named Nazca, of 528 bp, whereas CentPv2 is composed of tandemly organized monomers; (ii) CentPv1 and CentPv2 have undergone chromosome-specific homogenization; and (iii) CentPv1 and CentPv2 are not likely to be commingled in the genome. These findings suggest that two distinct sets of centromere sequences have evolved independently within the common bean genome, and provide insight into centromere satellite evolution. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Plasmodium vivax Tryptophan Rich Antigen PvTRAg36.6 Interacts with PvETRAMP and PvTRAg56.6 Interacts with PvMSP7 during Erythrocytic Stages of the Parasite

PubMed Central

Tyagi, Kriti; Hossain, Mohammad Enayet; Thakur, Vandana; Aggarwal, Praveen; Malhotra, Pawan; Mohmmed, Asif; Sharma, Yagya Dutta

2016-01-01

Plasmodium vivax is most wide spread and a neglected malaria parasite. There is a lack of information on parasite biology of this species. Genome of this parasite encodes for the largest number of tryptophan-rich proteins belonging to ‘Pv-fam-a’ family and some of them are potential drug/vaccine targets but their functional role(s) largely remains unexplored. Using bacterial and yeast two hybrid systems, we have identified the interacting partners for two of the P. vivax tryptophan-rich antigens called PvTRAg36.6 and PvTRAg56.2. The PvTRAg36.6 interacts with early transcribed membrane protein (ETRAMP) of P.vivax. It is apically localized in merozoites but in early stages it is seen in parasite periphery suggesting its likely involvement in parasitophorous vacuole membrane (PVM) development or maintenance. On the other hand, PvTRAg56.2 interacts with P.vivax merozoite surface protein7 (PvMSP7) and is localized on merozoite surface. Co-localization of PvTRAg56.2 with PvMSP1 and its molecular interaction with PvMSP7 probably suggest that, PvTRAg56.2 is part of MSP-complex, and might assist or stabilize the protein complex at the merozoite surface. In conclusion, the PvTRAg proteins have different sub cellular localizations and specific associated functions during intra-erythrocytic developmental cycle. PMID:26954579

Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificity ▿ #

PubMed Central

Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B.; Graham, James H.; Setubal, João C.; Wang, Nian

2011-01-01

Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity. PMID:21908674

Pulmonary vein activity does not predict the outcome of catheter ablation for persistent atrial fibrillation: A long-term multicenter prospective study.

PubMed

Prabhu, Sandeep; Kalla, Manish; Peck, Kah Y; Voskoboinik, Aleksandr; McLellan, Alex J A; Pathik, Bupesh; Nalliah, Chrishan J; Wong, Geoff R; Sugumar, Hariharan; Azzopardi, Sonia M; Lee, Geoffrey; Ling, Liang-Han; Kalman, Jonathan M; Kistler, Peter M

2018-03-02

Pulmonary vein (PV) isolation (PVI) remains the cornerstone of catheter ablation (CA) in persistent atrial fibrillation (AF) (PeAF), although less successful than for paroxysmal AF. Whether rapid or fibrillatory (PV AF) PV firing may identify patients with PeAF more likely to benefit from a PV-based ablation approach is unclear. The purpose of this study was to determine the relationship between the PV cycle length (PVCL) and the PV AF outcome after CA. Before ablation, the multipolar catheter was placed in each PV and the left atrial appendage (LAA) for 100 consecutive cycles. The presence of PV AF, the average PVCL of all 4 veins (PV 4VAverage ), the fastest vein average (PV FVAverage ), the fastest cycle length (PV Fast ) both individually and relative to the average LAA cycle length were calculated. The ablation strategy included PVI and posterior wall isolation with a minimum of 12 months follow-up. A total of 123 patients underwent CA (age 62 ± 9.1 years; CHA 2 DS 2 -VASC score 1.6 ± 1.1; left ventricular ejection fraction 48% ± 13%; left atrial area 31 ± 8.7 cm 2 ; AF duration 16 ± 17 months). PVI was achieved in 100% of patients. Multiprocedure success (MPS; freedom from AF/atrial tachycardia episodes lasting >30 seconds) was achieved in 76% of patients at 24 ± 8.1 months of follow-up after 1.2 ± 0.4 procedures. PV activity was not associated with MPS either absolutely (PV 4VAverage [MPS no vs yes: 178 ± 27 ms vs 177 ± 24 ms; P = .92], PV FVAverage [P = .69], or PV Fast [P = .82]) or as a ratio relative to the LAA cycle length (PV 4VAverage /LAA 1.05 ± 0.11 vs 1.06 ± 0.21; P = .87). The presence of PV AF (31% vs 47%; P = .13) did not predict MPS. The rapidity of PV firing or presence of fibrillation within the PV was not predictive of outcome of CA for PeAF. PV activity does not identify patients most likely to benefit from a PV-based ablation strategy. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure

NASA Astrophysics Data System (ADS)

May, Matthias M.; Lewerenz, Hans-Joachim; Lackner, David; Dimroth, Frank; Hannappel, Thomas

2015-09-01

Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators.

Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure

PubMed Central

May, Matthias M.; Lewerenz, Hans-Joachim; Lackner, David; Dimroth, Frank; Hannappel, Thomas

2015-01-01

Photosynthesis is nature's route to convert intermittent solar irradiation into storable energy, while its use for an industrial energy supply is impaired by low efficiency. Artificial photosynthesis provides a promising alternative for efficient robust carbon-neutral renewable energy generation. The approach of direct hydrogen generation by photoelectrochemical water splitting utilizes customized tandem absorber structures to mimic the Z-scheme of natural photosynthesis. Here a combined chemical surface transformation of a tandem structure and catalyst deposition at ambient temperature yields photocurrents approaching the theoretical limit of the absorber and results in a solar-to-hydrogen efficiency of 14%. The potentiostatically assisted photoelectrode efficiency is 17%. Present benchmarks for integrated systems are clearly exceeded. Details of the in situ interface transformation, the electronic improvement and chemical passivation are presented. The surface functionalization procedure is widely applicable and can be precisely controlled, allowing further developments of high-efficiency robust hydrogen generators. PMID:26369620

Development of an Efficient Entire-Capsid-Coding-Region Amplification Method for Direct Detection of Poliovirus from Stool Extracts

PubMed Central

Kilpatrick, David R.; Nakamura, Tomofumi; Burns, Cara C.; Bukbuk, David; Oderinde, Soji B.; Oberste, M. Steven; Kew, Olen M.; Pallansch, Mark A.; Shimizu, Hiroyuki

2014-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. PMID:25339406

The Terawatt Challenge

NASA Astrophysics Data System (ADS)

Haegel, Nancy

In response to concerns about accelerating climate change, the world is uniting to both envision and enable a global energy system that supports a sustainable environment and broad economic prosperity. Growth in the technology and the deployment of renewable energy has been dramatic. Evidence can be seen in the growth of photovoltaics (PV) and wind as contributors to worldwide electricity production over the last decade. PV and wind provided 1.2% and 3.7% of global electricity production in 2015, compared to 0.1% and 1.3% respectively in 2005. These numbers indicate both the rapid increase in the rate of deployment, as well as the remaining work to be done to extend this trend to transform a massive energy system and provide a significant fraction of the world's future energy demand with renewable energy. Based on recent trends, it is highly likely that global cumulative PV installation will reach terawatt scale in the next few decades. The challenges, as well as the resulting impact, vary greatly depending on whether we envision 1 TW ( 15% of 2015 global electricity capacity), 3 TW ( 50% of 2015 global electricity capacity) or 10 TW, a level that could drive electrification of transportation and industrial sectors and production of solar fuels. This presentation will draw upon the work of the 2016 GA-SERI (Global Alliance of Solar Energy Research Institutes) Terawatt Workshop to assess the feasibility and summarize the challenges for PV as a primary energy source. These challenges include the continuing demand for improved efficiency and reliability, the required magnitude of capital expenditure, the need for a sustainable industry (both financially and environmentally), as well as needs for grid modernization and consistent policies that support global climate goals. Physicists can play important roles in addressing this full range of challenges, from materials science to public policy, as well as in education of the public and its future leaders.

Positive correlation between postoperative tumor recurrence and changes in circulating tumor cell counts in pulmonary venous blood (pvCTC) during surgical manipulation in non-small cell lung cancer.

PubMed

Hashimoto, Masaki; Tanaka, Fumihiro; Yoneda, Kazue; Takuwa, Teruhisa; Matsumoto, Seiji; Okumura, Yoshitomo; Kondo, Nobuyuki; Tsujimura, Tohru; Nakano, Takashi; Hasegawa, Seiki

2018-01-01

In non-small cell lung cancer (NSCLC), circulating tumor cells (CTC) are shed and circulate to the peripheral blood through the pulmonary vein. Previously, CTC count in pulmonary venous blood (pvCTC) was shown to significantly increase after surgical manipulation. Therefore, we assessed the correlation between the changes in the pvCTC count (ΔpvCTC) and clinical outcomes. Consecutive patients with peripheral-type, NSCLC, who underwent lobectomy or bi-lobectomy through open thoracotomy, were enrolled prospectively. Before and after lobectomy, 2.5 mL of blood was drawn from the associated lobar pulmonary vein (PV), and was served for the quantitative evaluation of CTC using the CellSearch ® system. The cut-off point of ΔpvCTC was determined according to clinical outcomes and ΔpvCTC using receiver operation characteristic (ROC) curve. Then the correlation between ΔpvCTC and clinical outcomes was evaluated by Kaplan-Meier analyses and log-rank test. In addition, the correlation between ΔpvCTC and perioperative variables was assessed. A total of 30 patients were enrolled, tumor recurrence occurred in 11 patients over a median follow-up of 64.4 months. Of these, 7 patients had distant metastasis and 4 had local recurrence. The median ΔpvCTC was 49 cells/2.5 mL, and pvCTC-count was increased during surgical manipulation in 24 patients (80%). We divided patients into two groups based on ΔpvCTC with the cut-off value as 119 cells/2.5 mL according to ROC curve. Significant shorter time to distant metastasis (TDM) (P=0.0123) was observed in high ΔpvCTC group (ΔpvCTC ≥119 cells/2.5 mL) than low ΔpvCTC group (ΔpvCTC <119 cells/ 2.5mL). Neither disease-free survival (DFS) nor overall survival (OS) was significantly correlated with ΔpvCTC. Increasing pvCTC count during surgical manipulation was significantly correlated with postoperative distant metastasis in completely resected NSCLC patients. Significant shorter TDM was observed in patient with high ΔpvCTC group.

Purification and characterization of parvalbumins, the major allergens in red stingray (Dasyatis akajei).

PubMed

Cai, Qiu-Feng; Liu, Guang-Ming; Li, Teng; Hara, Kenji; Wang, Xi-Chang; Su, Wen-Jin; Cao, Min-Jie

2010-12-22

Fish has received increasing attention because it induces IgE-mediated food allergy. Parvalbumin (PV) represents the major allergen of fish, and IgE cross-reactivity to PV in various teleost fish species has been shown, while little information is available about allergens in elasmobranch fish. In this study, two PV isoforms (named as PV-I and PV-II) from red stingray (Dasyatis akajei) were purified to homogeneity by a series of procedures including ammonium sulfate precipitation and column chromatographies of DEAE-Sepharose and Sephacryl S-200. Purified PVs revealed a single band on tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular masses of PV-I and PV-II were 12.29 and 11.95 kDa, respectively, as determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Western blot using antifrog PV monoclonal antibody (PARV-19) showed positive reactions to the two proteins, confirming that they were PVs, although their immunological reactivities were weaker than those of PV from silver carp. The N-terminal amino acid sequence of PV-I was determined, and comparison with PVs from other fish species showed low homology between teleost and elasmobranch fish. The isoelectric points of PV-I and PV-II were 5.4 and 5.0, respectively, as determined by two-dimensional electrophoresis (2-DE), suggesting that both isoforms belong to the α-group. IgE immunoblotting analysis showed that sera from fish-allergic patients reacted to both PV-I and PV-II from red stingray. Thermal stability revealed that PV-I easily formed oligomers than PV-II, which might contribute to the maintenance of its allerginicity during heat processing.

Energy balance of the global photovoltaic (PV) industry--is the PV industry a net electricity producer?

PubMed

Dale, Michael; Benson, Sally M

2013-04-02

A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

Effect of Thermoelectric Cooling (TEC) module and the water flow heatsink on Photovoltaic (PV) panel performance

NASA Astrophysics Data System (ADS)

Amelia, A. R.; Jusoh, MA; Shamira Idris, Ida

2017-11-01

Photovoltaic (PV) panel suffers in low conversion efficiency of the output performance affected by the elevated operating temperature of the PV panel. It is important to keep the PV panel to operate at low temperature. To address this issue, this paper proposes the cooling system using thermoelectric cooling (TEC) and water block heatsink for enhancing the PV panel output performance. These both types cooling system were designed located on the back side of the PV panel to cool down the operating temperature of the PV panel. To evaluate the function for the existing cooling systems, the experiment was subsequently performed for PV panel without and with different design of the cooling system in outdoor weather conditions. By comparing the experimental results, it is concluded that by the hybrid cooling system which combining TEC module and the water block heatsink could improve the output performance of the PV panel. By the reduction temperature of the PV panel by 16.04 %, the average output power of the PV panel has been boosted up from 8.59 W to 9.03 W. In short, the output power of the PV panel was enhanced by the reduction of the operating temperature of the PV panel.

A lower intensity of treatment may underlie the increased risk of thrombosis in young patients with masked polycythaemia vera.

PubMed

Lussana, Federico; Carobbio, Alessandra; Randi, Maria L; Elena, Chiara; Rumi, Elisa; Finazzi, Guido; Bertozzi, Irene; Pieri, Lisa; Ruggeri, Marco; Palandri, Francesca; Polverelli, Nicola; Elli, Elena; Tieghi, Alessia; Iurlo, Alessandra; Ruella, Marco; Cazzola, Mario; Rambaldi, Alessandro; Vannucchi, Alessandro M; Barbui, Tiziano

2014-11-01

In patients who do not meet the World Health Organization (WHO) criteria for overt polycythaemia vera (PV), a diagnosis of masked PV (mPV) can be determined. A fraction of mPV patients may display thrombocytosis, thus mimicking essential thrombocythaemia (ET). No previous studies have examined clinical outcomes of mPV among young JAK2-mutated patients. We analysed a retrospective cohort of 538 JAK2-mutated patients younger than 40 years, after a re-assessment of the diagnosis according to the haemoglobin threshold for mPV. In this cohort of patients, 97 (18%) met the WHO criteria for PV, 66 patients (12%) were classified as mPV and 375 (70%) as JAK2-mutated ET. Surprisingly, a significant difference in the incidence of thrombosis was found when comparing mPV versus overt PV patients (P = 0·04). In multivariate analysis, the only factor accounting for the difference in the risk of thrombosis was the less frequent use of phlebotomies and cytoreduction in mPV patients compared to those with overt PV. Thus, we emphasize the need for the identification of mPV in young JAK2-mutated patients in order to optimize their treatments. © 2014 John Wiley & Sons Ltd.

Photovoltaics as a terrestrial energy source. Volume 2: System value

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Assumptions and techniques employed by the electric utility industry and other electricity planners to make estimates of the future value of photovoltaic (PV) systems interconnected with U.S. electric utilities were examined. Existing estimates of PV value and their interpretation and limitations are discussed. PV value is defined as the marginal private savings accruing to potential PV owners. For utility-owned PV systems, these values are shown to be the after-tax savings in conventional fuel and capacity displaced by the PV output. For non-utility-owned (distributed) systems, the utility's savings in fuel and capacity must first be translated through the electric rate structure (prices) to the potential PV system owner. Base-case estimates of the average value of PV systems to U.S. utilities are presented. The relationship of these results to the PV Program price goals and current energy policy is discussed; the usefulness of PV output quantity goals is also reviewed.

Synthesis, characterization, and antibacterial activity of chitosan/TiO2 nanocomposite against Xanthomonas oryzae pv. oryzae.

PubMed

Li, Bin; Zhang, Yang; Yang, Yingzi; Qiu, Wen; Wang, Xiaoxuan; Liu, Baoping; Wang, Yanli; Sun, Guochang

2016-11-05

This present study deals with synthesis, characterization and antibacterial activity of chitosan/TiO2 nanocomposites. Results indicated that chitosan/TiO2 nanocomposite at the ratio of 1:5 showed the strongest inhibition in growth of rice bacterial pathogen Xanthomonas oryzae pv. oryzae (Xoo). Furthermore, the antibacterial activity of chitosan/TiO2 nanocomposite against Xoo is significantly higher than that of the two individual components under both light and dark conditions. Regardless of the presence or absence of extracellular polymeric substances, chitosan/TiO2 nanocomposite showed strong antibacterial activity, however, the absence increased the sensitivity of Xoo to chitosan/TiO2 nanocomposite. In addition, the surface morphology and physicochemical properties of chitosan/TiO2 nanocomposite is different from the two individual components based on scanning electron microscopic observation, fourier transform infrared spectra, and X-ray diffraction pattern, as well as elemental and thermo gravimetric analysis. Overall, this study indicated that this synthesized chitosan/TiO2 nanocomposite is promising to be developed as a new antibacterial material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tin Selenide (SnSe): Growth, Properties, and Applications

PubMed Central

Shi, Weiran; Gao, Minxuan; Wei, Jinping; Gao, Jianfeng; Fan, Chenwei; Ashalley, Eric; Wang, Zhiming

2018-01-01

Abstract The indirect bandgap semiconductor tin selenide (SnSe) has been a research hotspot in the thermoelectric fields since a ZT (figure of merit) value of 2.6 at 923 K in SnSe single crystals along the b‐axis is reported. SnSe has also been extensively studied in the photovoltaic (PV) application for its extraordinary advantages including excellent optoelectronic properties, absence of toxicity, cheap raw materials, and relative abundance. Moreover, the thermoelectric and optoelectronic properties of SnSe can be regulated by the structural transformation and appropriate doping. Here, the studies in SnSe research, from its evolution to till now, are reviewed. The growth, characterization, and recent developments in SnSe research are discussed. The most popular growth techniques that have been used to prepare SnSe materials are discussed in detail with their recent progress. Important phenomena in the growth of SnSe as well as the problems remaining for future study are discussed. The applications of SnSe in the PV fields, Li‐ion batteries, and other emerging fields are also discussed. PMID:29721411

Tin Selenide (SnSe): Growth, Properties, and Applications.

PubMed

Shi, Weiran; Gao, Minxuan; Wei, Jinping; Gao, Jianfeng; Fan, Chenwei; Ashalley, Eric; Li, Handong; Wang, Zhiming

2018-04-01

The indirect bandgap semiconductor tin selenide (SnSe) has been a research hotspot in the thermoelectric fields since a ZT (figure of merit) value of 2.6 at 923 K in SnSe single crystals along the b -axis is reported. SnSe has also been extensively studied in the photovoltaic (PV) application for its extraordinary advantages including excellent optoelectronic properties, absence of toxicity, cheap raw materials, and relative abundance. Moreover, the thermoelectric and optoelectronic properties of SnSe can be regulated by the structural transformation and appropriate doping. Here, the studies in SnSe research, from its evolution to till now, are reviewed. The growth, characterization, and recent developments in SnSe research are discussed. The most popular growth techniques that have been used to prepare SnSe materials are discussed in detail with their recent progress. Important phenomena in the growth of SnSe as well as the problems remaining for future study are discussed. The applications of SnSe in the PV fields, Li-ion batteries, and other emerging fields are also discussed.

Predicting mixture phase equilibria and critical behavior using the SAFT-VRX approach.

PubMed

Sun, Lixin; Zhao, Honggang; Kiselev, Sergei B; McCabe, Clare

2005-05-12

The SAFT-VRX equation of state combines the SAFT-VR equation with a crossover function that smoothly transforms the classical equation into a nonanalytical form close to the critical point. By a combinination of the accuracy of the SAFT-VR approach away from the critical region with the asymptotic scaling behavior seen at the critical point of real fluids, the SAFT-VRX equation can accurately describe the global fluid phase diagram. In previous work, we demonstrated that the SAFT-VRX equation very accurately describes the pvT and phase behavior of both nonassociating and associating pure fluids, with a minimum of fitting to experimental data. Here, we present a generalized SAFT-VRX equation of state for binary mixtures that is found to accurately predict the vapor-liquid equilibrium and pvT behavior of the systems studied. In particular, we examine binary mixtures of n-alkanes and carbon dioxide + n-alkanes. The SAFT-VRX equation accurately describes not only the gas-liquid critical locus for these systems but also the vapor-liquid equilibrium phase diagrams and thermal properties in single-phase regions.

An investigation of the maximum penetration level of a photovoltaic (PV) system into a traditional distribution grid

NASA Astrophysics Data System (ADS)

Chalise, Santosh

Although solar photovoltaic (PV) systems have remained the fastest growing renewable power generating technology, variability as well as uncertainty in the output of PV plants is a significant issue. This rapid increase in PV grid-connected generation presents not only progress in clean energy but also challenges in integration with traditional electric power grids which were designed for transmission and distribution of power from central stations. Unlike conventional electric generators, PV panels do not have rotating parts and thus have no inertia. This potentially causes a problem when the solar irradiance incident upon a PV plant changes suddenly, for example, when scattered clouds pass quickly overhead. The output power of the PV plant may fluctuate nearly as rapidly as the incident irradiance. These rapid power output fluctuations may then cause voltage fluctuations, frequency fluctuations, and power quality issues. These power quality issues are more severe with increasing PV plant power output. This limits the maximum power output allowed from interconnected PV plants. Voltage regulation of a distribution system, a focus of this research, is a prime limiting factor in PV penetration levels. The IEEE 13-node test feeder, modeled and tested in the MATLAB/Simulink environment, was used as an example distribution feeder to analyze the maximum acceptable penetration of a PV plant. The effect of the PV plant's location was investigated, along with the addition of a VAR compensating device (a D-STATCOM in this case). The results were used to develop simple guidelines for determining an initial estimate of the maximum PV penetration level on a distribution feeder. For example, when no compensating devices are added to the system, a higher level of PV penetration is generally achieved by installing the PV plant close to the substation. The opposite is true when a VAR compensator is installed with the PV plant. In these cases, PV penetration levels over 50% may be safely achieved.

PV FAQs: Does the world have enough materials for PV to help address climate change?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2005-06-01

In the ongoing discussion of what needs to be done to stabilize atmospheric CO2 by mid-century (Hoffert 1998), one possible option would be to add about 10-20 terawatts (trillion watts, or TW) of photovoltaics (PV) in place of conventional sources. PV would help because, unlike burning fossil fuels, it produces no CO2. However, 10-20 TW is an enormous amount of energy. In peak Watts, the way PV installations are generally rated, it is about 50-100 TWpeak (TWp) of PV. Would we have enough materials to make this much PV? As we explain in this PV FAQ, we think our planetmore » has enough feedstock materials for PV to meet the ''TW challenge.''« less

Wavelet-based variability of Yellow River discharge at 500-, 100-, and 50-year timescales

NASA Astrophysics Data System (ADS)

Su, Lu; Miao, Chiyuan; Duan, Qingyun

2017-04-01

Water scarcity in the Yellow River, China, has become increasingly severe over the past half century. In this paper, wavelet transform analysis was used to detect the variability of observed and reconstructed streamflow in the Yellow River at 500-, 100-, and 50-year timescales. The periodicity of the streamflow series and the co-varying relationships between streamflow and atmospheric circulation indices / sunspot number were assessed via the continuous wavelet transform (CWT) and the wavelet coherence transform (WTC). The CWT results showed intermittent oscillations in streamflow with increasing periodicities of 1-6 years at all timescales. Significant multidecadal and century-scale periodicities were identified in the 500-year streamflow series. The WTC results showed intermittent interannual covariance of streamflow with atmospheric circulation indices and sunspots. At the 50-year timescale, there were significant decadal oscillations between streamflow and the Arctic Oscillation (AO) and the Pacific Decadal Oscillation (PDO), and bidecadal oscillations with the PDO. At the 100-year timescale, there were significant decadal oscillations between streamflow and Niño 3.4, the AO, and sunspots. At the 500-year timescale, streamflow in the middle reaches of the Yellow River showed prominent covariance with the AO with an approximately 32-year periodicity, and with sunspots with an approximately 80-year periodicity. Atmospheric circulation indices modulate streamflow by affecting temperature and precipitation. Sunspots impact streamflow variability by influencing atmospheric circulation, resulting in abundant precipitation. In general, for both the CWT and the WTC results, the periodicities were spatially continuous, with a few gradual changes from upstream to downstream resulting from the varied topography and runoff. At the temporal scale, the periodicities were generally continuous over short timescales and discontinuous over longer timescales.

Wavelet-based Variability of Yellow River Discharge at 500-, 100-, and 50-Year Timescales

NASA Astrophysics Data System (ADS)

Su, L.

2017-12-01

Water scarcity in the Yellow River, China, has become increasingly severe over the past half century. In this paper, wavelet transform analysis was used to detect the variability of natural, observed, and reconstructed streamflow in the Yellow River at 500-, 100-, and 50-year timescales. The periodicity of the streamflow series and the co-varying relationships between streamflow and atmospheric circulation indices/sunspot number were assessed by means of continuous wavelet transform (CWT) and wavelet transform coherence (WTC) analyses. The CWT results showed intermittent oscillations in streamflow with increasing periodicities of 1-6 years at all timescales. Significant multidecadal and century-scale periodicities were identified in the 500-year streamflow series. The WTC results showed intermittent interannual covariance of streamflow with atmospheric circulation indices and sunspots. At the 50-year timescale, there were significant decadal oscillations between streamflow and the Arctic Oscillation (AO) and the Pacific Decadal Oscillation (PDO), and bidecadal oscillations with the PDO. At the 100-year timescale, there were significant decadal oscillations between streamflow and Niño 3.4, the AO, and sunspots. At the 500-year timescale, streamflow in the middle reaches of the Yellow River showed prominent covariance with the AO with an approximately 32-year periodicity, and with sunspots with an approximately 80-year periodicity. Atmospheric circulation indices modulate streamflow by affecting temperature and precipitation. Sunspots impact streamflow variability by influencing atmospheric circulation, resulting in abundant precipitation. In general, for both the CWT and the WTC results, the periodicities were spatially continuous, with a few gradual changes from upstream to downstream resulting from the varied topography and runoff. At the temporal scale, the periodicities were generally continuous over short timescales and discontinuous over longer timescales.

Assessment of the biophysical impacts of utility-scale photovoltaics through observations and modelling

NASA Astrophysics Data System (ADS)

Broadbent, A. M.; Georgescu, M.; Krayenhoff, E. S.; Sailor, D.

2017-12-01

Utility-scale solar power plants are a rapidly growing component of the solar energy sector. Utility-scale photovoltaic (PV) solar power generation in the United States has increased by 867% since 2012 (EIA, 2016). This expansion is likely to continue as the cost PV technologies decrease. While most agree that solar power can decrease greenhouse gas emissions, the biophysical effects of PV systems on surface energy balance (SEB), and implications for surface climate, are not well understood. To our knowledge, there has never been a detailed observational study of SEB at a utility-scale solar array. This study presents data from an eddy covariance observational tower, temporarily placed above a utility-scale PV array in Southern Arizona. Comparison of PV SEB with a reference (unmodified) site, shows that solar panels can alter the SEB and near surface climate. SEB observations are used to develop and validate a new and more complete SEB PV model. In addition, the PV model is compared to simpler PV modelling methods. The simpler PV models produce differing results to our newly developed model and cannot capture the more complex processes that influence PV SEB. Finally, hypothetical scenarios of PV expansion across the continental United States (CONUS) were developed using various spatial mapping criteria. CONUS simulations of PV expansion reveal regional variability in biophysical effects of PV expansion. The study presents the first rigorous and validated simulations of the biophysical effects of utility-scale PV arrays.

Modeling of a VMJ PV array under Gaussian high intensity laser power beam condition

NASA Astrophysics Data System (ADS)

Eom, Jeongsook; Kim, Gunzung; Park, Yongwan

2018-02-01

The high intensity laser power beaming (HILPB) system is one of the most promising systems in the long-rang wireless power transfer field. The vertical multi-junction photovoltaic (VMJ PV) array converts the HILPB into electricity to power the load or charges a battery. The output power of a VMJ PV array depends mainly on irradiance values of each VMJ PV cells. For simulating an entire VMJ PV array, the irradiance profile of the Gaussian HILPB and the irradiance level of the VMJ PV cell are mathematically modeled first. The VMJ PV array is modeled as a network with dimension m*n, where m represents the number of VMJ PV cells in a column, and n represents the number of VMJ PV cells in a row. In order to validate the results obtained in modeling and simulation, a laboratory setup was developed using 55 VMJ PV array. By using the output power model of VMJ PV array, we can establish an optimal power transmission path by the receiver based on the received signal strength. When the laser beam from multiple transmitters aimed at a VMJ PV array at the same time, the received power is the sum of all energy at a VMJ PV array. The transmitter sends its power characteristics as optically coded laser pulses and powers as HILPB. Using the attenuated power model and output power model of VMJ PV array, the receiver can estimate the maximum receivable powers from the transmitters and select optimal transmitters.

Development of an efficient entire-capsid-coding-region amplification method for direct detection of poliovirus from stool extracts.

PubMed

Arita, Minetaro; Kilpatrick, David R; Nakamura, Tomofumi; Burns, Cara C; Bukbuk, David; Oderinde, Soji B; Oberste, M Steven; Kew, Olen M; Pallansch, Mark A; Shimizu, Hiroyuki

2015-01-01

Laboratory diagnosis has played a critical role in the Global Polio Eradication Initiative since 1988, by isolating and identifying poliovirus (PV) from stool specimens by using cell culture as a highly sensitive system to detect PV. In the present study, we aimed to develop a molecular method to detect PV directly from stool extracts, with a high efficiency comparable to that of cell culture. We developed a method to efficiently amplify the entire capsid coding region of human enteroviruses (EVs) including PV. cDNAs of the entire capsid coding region (3.9 kb) were obtained from as few as 50 copies of PV genomes. PV was detected from the cDNAs with an improved PV-specific real-time reverse transcription-PCR system and nucleotide sequence analysis of the VP1 coding region. For assay validation, we analyzed 84 stool extracts that were positive for PV in cell culture and detected PV genomes from 100% of the extracts (84/84 samples) with this method in combination with a PV-specific extraction method. PV could be detected in 2/4 stool extract samples that were negative for PV in cell culture. In PV-positive samples, EV species C viruses were also detected with high frequency (27% [23/86 samples]). This method would be useful for direct detection of PV from stool extracts without using cell culture. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Speer, B.; Mendelsohn, M.; Cory, K.

Insuring solar photovoltaic (PV) systems poses certain challenges. Insurance premiums, which can represent a significant part of overall costs for PV developers, can affect market competition. The market for certain types of insurance products is limited. Historical loss data is lacking, and test data for the long-term viability of PV products under real-life conditions is limited. Insurers' knowledge about PV systems and the PV industry is uneven even as the industry introduces innovative contractual structures and business models. Interviews conducted for this report with PV project developers, insurance brokers, and underwriters suggest government actions aimed at better testing, data collection,more » and communication could facilitate the development of a market for PV insurance products. This report identifies actions by governments, national laboratories, and other stakeholders that could accelerate the development of insurance products in support PV systems. Such actions include: increasing understanding of the solar PV industry among insurance professionals; expanding the availability of PV historical loss data; evaluating the expansion of renewable energy business classification; developing module and component testing capabilities and services offered by federal labs; and, advancing industry standards for PV system installers.« less

Evidence of recombination and positive selection in cetacean papillomaviruses.

PubMed

Robles-Sikisaka, Refugio; Rivera, Rebecca; Nollens, Hendrik H; St Leger, Judy; Durden, Wendy N; Stolen, Megan; Burchell, Jennifer; Wellehan, James F X

2012-06-05

Papillomaviruses (PVs) are small DNA viruses that have been associated with increased epithelial proliferation. Over one hundred PV types have been identified in humans; however, only three have been identified in bottlenose dolphins (Tursiops truncatus) to date. Using rolling circle amplification and degenerate PCR, we identified four novel PV genomes of bottlenose dolphins. TtPV4, TtPV5 and TtPV6 were identified in genital lesions while TtPV7 was identified in normal genital mucosa. Bayesian analysis of the full-length L1 genes found that TtPV4 and TtPV7 group within the Upsilonpapillomavirus genus while TtPV5 and TtPV6 group with Omikronpapillomavirus. However, analysis of the E1 gene did not distinguish these genera, implying that these genes may not share a common history, consistent with recombination. Recombination analyses identified several probable events. Signals of positive selection were found mostly in the E1 and E2 genes. Recombination and diversifying selection pressures constitute important driving forces of cetacean PV evolution. Copyright © 2012 Elsevier Inc. All rights reserved.

A Non-Modeling Exploration of Residential Solar Photovoltaic (PV) Adoption and Non-Adoption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moezzi, Mithra; Ingle, Aaron; Lutzenhiser, Loren

Although U.S. deployment of residential rooftop solar photovoltaic (PV) systems has accelerated in recent years, PV is still installed on less than 1 percent of single-family homes. Most research on household PV adoption focuses on scaling initial markets and modeling predicted growth rather than considering more broadly why adoption occurs. Among the studies that have investigated the characteristics of PV adoption, most collected data from adopters, sometimes with additional non-adopter data, and rarely from people who considered but did not adopt PV. Yet the vast majority of Americans are non-adopters, and they are a diverse group - understanding their waysmore » of evaluating PV adoption is important. Similarly, PV is a unique consumer product, which makes it difficult to apply findings from studies of other technologies to PV. In addition, little research addresses the experience of households after they install PV. This report helps fill some of these gaps in the existing literature. The results inform a more detailed understanding of residential PV adoption, while helping ensure that adoption is sufficiently beneficial to adopters and even non-adopters.« less

Evidence of recombination and positive selection in cetacean papillomaviruses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robles-Sikisaka, Refugio, E-mail: refugio.robles1@gmail.com; Rivera, Rebecca, E-mail: RRivera@hswri.org; Nollens, Hendrik H., E-mail: Hendrik.Nollens@SeaWorld.com

2012-06-05

Papillomaviruses (PVs) are small DNA viruses that have been associated with increased epithelial proliferation. Over one hundred PV types have been identified in humans; however, only three have been identified in bottlenose dolphins (Tursiops truncatus) to date. Using rolling circle amplification and degenerate PCR, we identified four novel PV genomes of bottlenose dolphins. TtPV4, TtPV5 and TtPV6 were identified in genital lesions while TtPV7 was identified in normal genital mucosa. Bayesian analysis of the full-length L1 genes found that TtPV4 and TtPV7 group within the Upsilonpapillomavirus genus while TtPV5 and TtPV6 group with Omikronpapillomavirus. However, analysis of the E1 genemore » did not distinguish these genera, implying that these genes may not share a common history, consistent with recombination. Recombination analyses identified several probable events. Signals of positive selection were found mostly in the E1 and E2 genes. Recombination and diversifying selection pressures constitute important driving forces of cetacean PV evolution.« less

Visible-Light Actinometry and Intermittent Illumination as Convenient Tools to Study Ru(bpy)3Cl2 Mediated Photoredox Transformations

PubMed Central

Pitre, Spencer P.; McTiernan, Christopher D.; Vine, Wyatt; DiPucchio, Rebecca; Grenier, Michel; Scaiano, Juan C.

2015-01-01

Photoredox catalysis provides many green opportunities for radical-mediated synthetic transformations. However, the determination of the underlying mechanisms has been challenging due to lack of quantitative methods that can be easily implemented in synthetic labs, where this research tends to be centered. We report here on the development, characterization and calibration of a novel actinometer based on the photocatalyst tris(2,2′-bipyridyl)ruthenium(II) chloride (Ru(bpy)3Cl2). By using the same molecule as the photocatalyst and the actinometer, we eliminate problems associated with matching sample spectral distribution, lamp-sample spectral overlap and other problems intrinsic to doing quantitative photochemistry in a laboratory that has little expertise in this area. In order to validate our actinometer system in determining the quantum yield of a Ru(bpy)3Cl2 photosensitized reaction, we test the Ru(bpy)3Cl2 catalyzed oxidation of benzhydrol to benzophenone as a model chain reaction. We also revive the rotating sector method by updating the technique for modern LED technologies and demonstrate how intermittent illumination on the timescale of milliseconds to seconds can help probe a chain reaction, using the benzhydrol to benzophenone oxidation to validate the technique. We envision these methods to have great implications in the field of photoredox catalysis, providing researchers with valuable research tools. PMID:26578341

NREL Photovoltaic Program. FY 1994 annual report, October 1, 1993--September 30, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-06-01

This report summarizes the in-house and subcontracted research and development activities under the National renewable Energy Laboratory (NREL) Photovoltaics (PV) program for fiscal year 1994. Research is organized under the following areas; PV program management; crystalline silicon and advanced devices; thin-film PV technologies; PV manufacturing; PV module and system performance and engineering; and PV applications and markets.

PV FAQs: Will We Have Enough Materials for Energy-Significant PV Production?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2004-01-01

This PV FAQ fact sheet discusses whether we will have enough of the feedstock materials used for energy-significant PV production. The answer is that, for a set amount of PV production, we will indeed have enough materials.

Poliovirus immunity among pregnant females aged 15-44 years, Namibia, 2010.

PubMed

Cardemil, Cristina V; Jonas, Anna; Gerber, Sue; Weldon, William C; Oberste, M Steven; Beukes, Anita; Sawadogo, Souleymane; Patel, Sadhna V; Zeko, Sikota; Muroua, Clementine; Gaeb, Esegiel; Wannemuehler, Kathleen; Goodson, James L

2014-11-01

Poliovirus (PV) antibody seroprevalence studies assess population immunity, verify an immunization program's performance and vaccine efficacy, and guide polio eradication strategy. Namibia experienced a polio outbreak among adults in 2006, yet population seroimmunity was unknown. We tested 2061 specimens from Namibian pregnant females aged 15-44 years for neutralizing antibody to PV types 1-3 (PV1-3); all females were sampled during the 2010 National HIV Sentinel Survey. We determined the proportion of females seropositive for PV antibody by 5-year age strata, and analyzed factors associated with seropositivity, including age, gravidity, human immunodeficiency virus (HIV) infection status, residence, and antiretroviral treatment, by log-binomial regression. The seroprevalence was 94.6% for PV1, 97.0% for PV2, and 85.1% for PV3. HIV-positive females had significantly lower seroprevalence than HIV-negative females for PV1 (91.8% vs 95.3%; P<.01) and PV3 (80.0% vs 86.1%; P<.01) but not for PV2 (96.4% vs 97.1%; P=.3). The prevalence ratio of seropositivity for HIV-positive females versus HIV-negative females was 0.95 (95% confidence interval [CI], .92-.98) for PV1, 0.99 (95% CI, .97-1.01) for PV2, and 0.92 (95% CI, .87-.96) for PV3. Despite relatively high PV seroprevalence, Namibia might remain at risk for a PV outbreak, particularly in lower-seroprevalence populations, such as HIV-positive females. Namibia should continue to maintain high routine polio vaccination coverage. Published by Oxford University Press on behalf of the Infectious Diseases Society of America 2014. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Origin of the Outbreak in France of Pseudomonas syringae pv. actinidiae Biovar 3, the Causal Agent of Bacterial Canker of Kiwifruit, Revealed by a Multilocus Variable-Number Tandem-Repeat Analysis

PubMed Central

Cunty, A.; Cesbron, S.; Poliakoff, F.; Jacques, M.-A.

2015-01-01

The first outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 were detected in France in 2010. P. syringae pv. actinidiae causes leaf spots, dieback, and canker that sometimes lead to the death of the vine. P. syringae pv. actinidifoliorum, which is pathogenic on kiwi as well, causes only leaf spots. In order to conduct an epidemiological study to track the spread of the epidemics of these two pathogens in France, we developed a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). MLVA was conducted on 340 strains of P. syringae pv. actinidiae biovar 3 isolated in Chile, China, France, Italy, and New Zealand and on 39 strains of P. syringae pv. actinidifoliorum isolated in Australia, France, and New Zealand. Eleven polymorphic VNTR loci were identified in the genomes of P. syringae pv. actinidiae biovar 3 ICMP 18744 and of P. syringae pv. actinidifoliorum ICMP 18807. MLVA enabled the structuring of P. syringae pv. actinidiae biovar 3 and P. syringae pv. actinidifoliorum strains in 55 and 16 haplotypes, respectively. MLVA and discriminant analysis of principal components revealed that strains isolated in Chile, China, and New Zealand are genetically distinct from P. syringae pv. actinidiae strains isolated in France and in Italy, which appear to be closely related at the genetic level. In contrast, no structuring was observed for P. syringae pv. actinidifoliorum. We developed an MLVA scheme to explore the diversity within P. syringae pv. actinidiae biovar 3 and to trace the dispersal routes of epidemic P. syringae pv. actinidiae biovar 3 in Europe. We suggest using this MLVA scheme to trace the dispersal routes of P. syringae pv. actinidiae at a global level. PMID:26209667

Comparative Analysis and Considerations for PV Interconnection Standards in the United States and China

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gao, David Wenzhong; Muljadi, Eduard; Tian, Tian

The main objectives of this report are to evaluate China's photovoltaic (PV) interconnection standards and the U.S. counterparts and to propose recommendations for future revisions to these standards. This report references the 2013 report Comparative Study of Standards for Grid-Connected PV System in China, the U.S. and European Countries, which compares U.S., European, and China's PV grid interconnection standards; reviews various metrics for the characterization of distribution network with PV; and suggests modifications to China's PV interconnection standards and requirements. The recommendations are accompanied by assessments of four high-penetration PV grid interconnection cases in the United States to illustrate solutionsmore » implemented to resolve issues encountered at different sites. PV penetration in China and in the United States has significantly increased during the past several years, presenting comparable challenges depending on the conditions of the grid at the point of interconnection; solutions are generally unique to each interconnected PV installation or PV plant.« less

[Clinical Analysis of Driver Mutations in Patients with Ph Negative Myeloproliferative Neoplasms].

PubMed

He, Zhi-Peng; Tian, Hui-Yun; Tan, Ming; Wu, Yong

2018-06-01

To explore the relationship between driver mutations and clinical characteristics in patients with Philadelphia chromosome (Ph) negative myeloproliferative neoplasms (MPN), so as to provide evidence for diagno-sis and treatment of the disease. The clinical data of 410 patients with classic Ph negative MPN including 150 cases of polycythemia vera (PV), 188 cases of essential thrombocythemia (ET) and 72 cases of primary myelofibrosis (PMF) from January 2013 to December 2016 in Fujian Medical University Union Hospital were retrospectively analyzed. The PCR or DNA sequencing were used for JAK2 V617F, JAK2 exon12, CALR and MPL W515L/K mutation analyses, and follow-up information on patients was updated by direct phone call or follow-up in outpatient. Among the 410 patients with Ph negative MPN, 136 (33.2%) cases were asymptomatic at diagnosis. 389 cases were sequenced and JAK2 V617F was detected in 87.1% (122/140) of PV, 64.1% (118/184) of ET, 64.6% (42/65) of PMF; JAK2 exon 12 mutation in 1 case of PV; MPL W515L/K mutation in 1 case of ET and PMF, respectively; CALR mutation in 18(9.8%) cases of ET and 5 (7.7%) cases of PMF. JAK2 V617F mutated PV patients ocourred in older age: the white blood cell count, platelet count and incidence of splenomegaly were higher than JAK2-negative PV cases(P<0.05). Compared with JAK2 V617F mutated ET patients, CALR mutated ET cases displayed younger age, lower leukocyte count, higher platelet count and lower incidence of thrombosis; JAK2-negative ET cases had younger age, lower leukocyte count, lower hemoglobin level, higher platelet count and lower incidence of thrombosis(P<0.05). The incidence of splenomegaly in JAK2 V617F or CALR mutated PMF patients was both higher than that in JAK2-negative PMF cases, but the incidence of leukemia transformation in JAK2-negative PMF patients was higher than that in JAK2 V617F mutated cases (P<0.05). The types of driver mutations are closely related with the clinical features and prognosis in Ph - negative MPN patients.

Ensemble Data Assimilation of Photovoltaic Power Information in the Convection-permitting High-Resolution Model COSMO-DE

NASA Astrophysics Data System (ADS)

Declair, Stefan; Saint-Drenan, Yves-Marie; Potthast, Roland

2017-04-01

Determining the amount of weather dependent renewable energy is a demanding task for transmission system operators (TSOs) and wind and photovoltaic (PV) prediction errors require the use of reserve power, which generate costs and can - in extreme cases - endanger the security of supply. In the project EWeLiNE funded by the German government, the German Weather Service and the Fraunhofer Institute on Wind Energy and Energy System Technology develop innovative weather- and power forecasting models and tools for grid integration of weather dependent renewable energy. The key part in energy prediction process chains is the numerical weather prediction (NWP) system. Irradiation forecasts from NWP systems are however subject to several sources of error. For PV power prediction, weaknesses of the NWP model to correctly forecast i.e. low stratus, absorption of condensed water or aerosol optical depths are the main sources of errors. Inaccurate radiation schemes (i.e. the two-stream parametrization) are also known as a deficit of NWP systems with regard to irradiation forecast. To mitigate errors like these, latest observations can be used in a pre-processing technique called data assimilation (DA). In DA, not only the initial fields are provided, but the model is also synchronized with reality - the observations - and hence forecast errors are reduced. Besides conventional observation networks like radiosondes, synoptic observations or air reports of wind, pressure and humidity, the number of observations measuring meteorological information indirectly by means of remote sensing such as satellite radiances, radar reflectivities or GPS slant delays strongly increases. Numerous PV plants installed in Germany potentially represent a dense meteorological network assessing irradiation through their power measurements. Forecast accuracy may thus be enhanced by extending the observations in the assimilation by this new source of information. PV power plants can provide information on clouds, aerosol optical depth or low stratus in terms of remote sensing: the power output is strongly dependent on perturbations along the slant between sun position and PV panel. Since these data are not limited to the vertical column above or below the detector, it may thus complement satellite data and compensate weaknesses in the radiation scheme. In this contribution, the used DA technique (Local Ensemble Transform Kalman Filter, LETKF) is shortly sketched. Furthermore, the computation of the model power equivalents is described and first results are presented and discussed.

Methodological Guidelines on Net Energy Analysis of Photovoltaic Electricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raugei, Marco; Frischknecht, Rolf; Olson, Carol

Net Energy Analysis (NEA) is a structured, comprehensive method of quantifying the extent to which a given energy source is able to provide a net energy gain (i.e., an energy surplus) to the end user, after accounting for all the energy losses occurring along the chain of processes that are required to exploit it (i.e., for its extraction, processing and transformation into a usable energy carrier, and delivery to the end user), as well as for all the additional energy 'investments' that are required in order to carry out the same chain of processes. However, this general framework leaves themore » individual practitioner with a range of choices that can affect the results and thus, the conclusions of a NEA study. The current IEA PVPS guidelines were developed to provide guidance on assuring consistency, balance, and quality to enhance the credibility and reliability of the results from photovoltaic (PV) NEAs. The guidelines represent a consensus among the authors -- PV NEA experts in North America, Europe, and Asia -- for assumptions made on PV performance, process inputs and outputs, methods of analysis, and reporting of the results. Guidance is given on photovoltaic-specific parameters used as inputs in NEA and on choices and assumptions in inventory data analysis and on implementation of modelling approaches. A consistent approach towards system modelling, the functional unit, the system boundaries and allocation aspects enhances the credibility of PV electricity NEA studies and enables balanced NEA-based comparisons of different electricity producing technologies. This document provides an in-depth discussion of a common metric of NEA, namely the energy return on investment (EROI), and how this is to be interpreted vis-a-vis the deceptively similar-sounding metrics in the field of Life Cycle Assessment (LCA): cumulative energy demand (CED) and non-renewable cumulative energy demand (nr-CED) per unit output. Specifically, a number of key differences are highlighted between these metrics as applied to electricity production systems. Transparency in reporting is of the utmost importance as parameters vary with geographical zones, and a system's boundary conditions and modelling approach can affect the findings significantly. This guideline lists 16 items that should be reported in every NEA study of PV electricity.« less

The Evolving Market Structure of the U.S. Residential Solar PV Installation

Science.gov Websites

Solar PV Installation Industry, 2000-2016 The Evolving Market Structure of the U.S. Residential Solar PV residential solar photovoltaic (PV) system and that the residential PV installation industry has become more concentrated over time. From 2000 to 2016, the U.S. residential solar photovoltaic (PV) installation industry

Buffering PV output during cloud transients with energy storage

NASA Astrophysics Data System (ADS)

Moumouni, Yacouba

Consideration of the use of the major types of energy storage is attempted in this thesis in order to mitigate the effects of power output transients associated with grid-tied CPV systems due to fast-moving cloud coverage. The approach presented here is to buffer intermittency of CPV output power with an energy storage device (used batteries) purchased cheaply from EV owners or battery leasers. When the CPV is connected to the grid with the proper energy storage, the main goal is to smooth out the intermittent solar power and fluctuant load of the grid with a convenient control strategy. This thesis provides a detailed analysis with appropriate Matlab codes to put onto the grid during the day time a constant amount of power on one hand and on the other, shift the less valuable off-peak electricity to the on-peak time, i.e. between 1pm to 7pm, where the electricity price is much better. In this study, a range of base constant power levels were assumed including 15kW, 20kW, 21kW, 22kW, 23kW, 24kW and 25kW. The hypothesis based on an iterative solution was that the capacity of the battery was increased by steps of 5 while the base supply was decreased by the same step size until satisfactorily results were achieved. Hence, it turned out with the chosen battery capacity of 54kWh coupled to the data from the Amonix CPV 7700 unit for Las Vegas for a 3-month period, it was found that 20kW was the largest constant load the system can supply uninterruptedly to the utility company. Simulated results are presented to show the feasibility of the proposed scheme.

High-voltage zones within the pulmonary vein antra: Major determinants of acute pulmonary vein reconnections after atrial fibrillation ablation.

PubMed

Nagashima, Koichi; Watanabe, Ichiro; Okumura, Yasuo; Iso, Kazuki; Takahashi, Keiko; Watanabe, Ryuta; Arai, Masaru; Kurokawa, Sayaka; Nakai, Toshiko; Ohkubo, Kimie; Yoda, Shunichi; Hirayama, Atsushi

2017-08-01

Recurrence of atrial fibrillation (AF) after pulmonary vein isolation (PVI) is mainly due to PV reconnections. Patient-specific tissue characteristics that may contribute remain unidentified. This study aimed to assess the relationship between the bipolar electrogram voltage amplitudes recorded from the PV-left atrial (LA) junction and acute PV reconnection sites. Three-dimensional LA voltage maps created before an extensive encircling PVI in 47 AF patients (31 men; mean age 62 ± 11 years) were examined for an association between the EGM voltage amplitude recorded from the PV-LA junction and acute post-PVI PV reconnections (spontaneous PV reconnections and/or ATP-provoked dormant PV conduction). Acute PV reconnections were observed in 17 patients (36%) and in 24 (3%) of the 748 PV segments (16 segments per patient) and were associated with relatively high bipolar voltage amplitudes (3.26 ± 0.85 vs. 1.79 ± 1.15 mV, p < 0.0001) and a relatively low mean force-time integral (FTI) (428 ± 56 vs. 473 ± 76 gs, p = 0.0039) as well as FTI/PV-LA bipolar voltage (137 [106, 166] vs. 295 [193, 498] gs/mV, p < 0.0001). An analysis of the receiver operating characteristic curves revealed a high prognostic performance of the LA bipolar voltage and FTI/PV-LA bipolar voltage for acute PV reconnections (areas under the curve: 0.86 and 0.89, respectively); the best cutoff values were >2.12 mV and ≤183 gs/mV, respectively. The PV-LA voltage on the PV-encircling ablation line and FTI/PV-LA voltage were related to the acute post-PVI PV reconnections. A more durable ablation strategy is warranted for high-voltage zones.

Timothy Silverman | NREL

Science.gov Websites

physical phenomena, PV package reliability, and outdoor PV performance. At NREL, he performs research in advanced concept PV modules. Dr. Silverman studies the performance and reliability of PV modules, including previously studied the degradation of solder joints in high-concentration PV and the outdoor performance of

A Practical Irradiance Model for Bifacial PV Modules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-21

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be added tomore » the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using ray tracing software.« less

A Practical Irradiance Model for Bifacial PV Modules: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; MacAlpine, Sara; Deline, Chris

2017-06-15

A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors (CFs) to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be addedmore » to the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using the RADIANCE ray tracing program.« less

Breakeven Prices for Photovoltaics on Supermarkets in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ong, S.; Clark, N.; Denholm, P.

The photovoltaic (PV) breakeven price is the PV system price at which the cost of PV-generated electricity equals the cost of electricity purchased from the grid. This point is also called 'grid parity' and can be expressed as dollars per watt ($/W) of installed PV system capacity. Achieving the PV breakeven price depends on many factors, including the solar resource, local electricity prices, customer load profile, PV incentives, and financing. In the United States, where these factors vary substantially across regions, breakeven prices vary substantially across regions as well. In this study, we estimate current and future breakeven prices formore » PV systems installed on supermarkets in the United States. We also evaluate key drivers of current and future commercial PV breakeven prices by region. The results suggest that breakeven prices for PV systems installed on supermarkets vary significantly across the United States. Non-technical factors -- including electricity rates, rate structures, incentives, and the availability of system financing -- drive break-even prices more than technical factors like solar resource or system orientation. In 2020 (where we assume higher electricity prices and lower PV incentives), under base-case assumptions, we estimate that about 17% of supermarkets will be in utility territories where breakeven conditions exist at a PV system price of $3/W; this increases to 79% at $1.25/W (the DOE SunShot Initiative's commercial PV price target for 2020). These percentages increase to 26% and 91%, respectively, when rate structures favorable to PV are used.« less

MUNI Ways and Structures Building Integrated Solar Membrane Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Randall

The initial goal of the MUNI Ways and Structures Building Integrated Solar Membrane Installation Project was for the City and County of San Francisco (CCSF) to gain experience using the integrated higher efficiency solar photovoltaic (PV) single-ply membrane product, as it differs from the conventional, low efficiency, thin-film PV products, to determine the feasibility of success of larger deployment. As several of CCSF’s municipal rooftops are constrained with respect to weight restrictions, staff of the Energy Generation Group of the San Francisco Public Utilities Commission (SFPUC) proposed to install a solar PV system using single-ply membrane The installation of themore » 100 kW (DC-STC) lightweight photo voltaic (PV) system at the MUNI Ways and Structures Center (700 Pennsylvania Ave., San Francisco) is a continuation of the commitment of the City and County of San Francisco (CCSF) to increase the pace of municipal solar development, and serve its municipal facilities with clean renewable energy. The fourteen (14) solar photovoltaic systems that have already been installed at CCSF municipal facilities are assisting in the reduction of fossil-fuel use, and reduction of greenhouse gases from fossil combustion. The MUNI Ways & Structures Center roof has a relatively low weight-bearing capacity (3.25 pounds per square foot) and use of traditional crystalline panels was therefore rejected. Consequently it was decided to use the best available highest efficiency Building-Integrated PV (BIPV) technology, with consideration for reliability and experience of the manufacturer which can meet the low weight-bearing capacity criteria. The original goal of the project was to provide an opportunity to monitor the results of the BIPV technology and compare these results to other City and County of San Francisco installed PV systems. The MUNI Ways and Structures Center was acquired from the Cookson Doors Company, which had run the Center for many decades. The building was renovated in 1998, but the existing roof had not been designed to carry a large load. Due to this fact, a complete roofing and structural analysis had to be performed to match the available roof loading to the existing and/or new solar PV technology, and BIPV was considered an excellent solution for this structure with the roof weight limitations. The solar BIPV system on the large roof area was estimated to provide about 25% of the total facility load with an average of 52,560 kWh per month. In order to accomplish the goals of the project, the following steps were performed: 1. SFPUC and consultants evaluated the structural capability of the facility roof, with recommendations for improvements necessary to accommodate the solar PV system and determine the suitable size of the system in kilowatts. The electrical room and switchgear were evaluated for any improvements necessary and to identify any constraints that might impede the installation of necessary inverters, transformers or meters. 2. Development of a design-build Request for Proposal (RFP) to identify the specifications for the solar PV system, and to include SFPUC technical specifications, equipment warranties and performance warranties. Due to potential labor issues in the local solar industry, SFPUC adjusted the terms of the RFP to more clearly define scope of work between electricians, roofers and laborers. 3. Design phase of project included electrical design drawings, calculations and other construction documents to support three submittals: 50% (preliminary design), 90% (detailed design) and 100% (Department of Building Inspection permit approved). 4. Installation of solar photovoltaic panels, completion of conduit and wiring work, connection of inverters, isolation switches, meters and Data Acquisition System by Contractor (Department of Public Works). 5. Commissioning of system, including all necessary tests to make the PV system fully functional and operational at its rated capacity of 100 kW (DC-STC). Following completion of these steps, the solar PV system was installed and fully integrated by late October 2013. The interconnection with PG&E utility grid was completed and the system began generating power on November 21, 2013. The projected annual energy generation for the system is estimated at 127,120 kWh/year.« less

An Analysis of the Effects of Residential Photovoltaic Energy Systems on Home Sales Prices in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Cappers, Peter; Wiser, Ryan

2011-04-19

An increasing number of homes in the U.S. have sold with photovoltaic (PV) energy systems installed at the time of sale, yet relatively little research exists that estimates the marginal impacts of those PV systems on home sale prices. A clearer understanding of these possible impacts might influence the decisions of homeowners considering the installation of a PV system, homebuyers considering the purchase of a home with PV already installed, and new home builders considering including PV as an optional or standard product on their homes. This research analyzes a large dataset of California homes that sold from 2000 throughmore » mid-2009 with PV installed. It finds strong evidence that homes with PV systems sold for a premium over comparable homes without PV systems during this time frame. Estimates for this premium expressed in dollars per watt of installed PV range, on average, from roughly $4 to $5.5/watt across a large number of hedonic and repeat sales model specifications and robustness tests. When expressed as a ratio of the sales price premium of PV to estimated annual energy cost savings associated with PV, an average ratio of 14:1 to 19:1 can be calculated; these results are consistent with those of the more-extensive existing literature on the impact of energy efficiency on sales prices. When the data are split among new and existing homes, however, PV system premiums are markedly affected. New homes with PV show premiums of $2.3-2.6/watt, while existing homes with PV show premiums of more than $6/watt. Reasons for this discrepancy are suggested, yet further research is warranted. A number of other areas where future research would be useful are also highlighted.« less

Comparison of three different methods of perturbing the potential vorticity field in mesoscale forecasts of Mediterranean heavy precipitation events: PV-gradient, PV-adjoint and PV-satellite

NASA Astrophysics Data System (ADS)

Vich, M.; Romero, R.; Richard, E.; Arbogast, P.; Maynard, K.

2010-09-01

Heavy precipitation events occur regularly in the western Mediterranean region. These events often have a high impact on the society due to economic and personal losses. The improvement of the mesoscale numerical forecasts of these events can be used to prevent or minimize their impact on the society. In previous studies, two ensemble prediction systems (EPSs) based on perturbing the model initial and boundary conditions were developed and tested for a collection of high-impact MEDEX cyclonic episodes. These EPSs perturb the initial and boundary potential vorticity (PV) field through a PV inversion algorithm. This technique ensures modifications of all the meteorological fields without compromising the mass-wind balance. One EPS introduces the perturbations along the zones of the three-dimensional PV structure presenting the local most intense values and gradients of the field (a semi-objective choice, PV-gradient), while the other perturbs the PV field over the MM5 adjoint model calculated sensitivity zones (an objective method, PV-adjoint). The PV perturbations are set from a PV error climatology (PVEC) that characterizes typical PV errors in the ECMWF forecasts, both in intensity and displacement. This intensity and displacement perturbation of the PV field is chosen randomly, while its location is given by the perturbation zones defined in each ensemble generation method. Encouraged by the good results obtained by these two EPSs that perturb the PV field, a new approach based on a manual perturbation of the PV field has been tested and compared with the previous results. This technique uses the satellite water vapor (WV) observations to guide the correction of initial PV structures. The correction of the PV field intents to improve the match between the PV distribution and the WV image, taking advantage of the relation between dark and bright features of WV images and PV anomalies, under some assumptions. Afterwards, the PV inversion algorithm is applied to run a forecast with the corresponding perturbed initial state (PV-satellite). The non hydrostatic MM5 mesoscale model has been used to run all forecasts. The simulations are performed for a two-day period with a 22.5 km resolution domain (Domain 1 in http://mm5forecasts.uib.es) nested in the ECMWF large-scale forecast fields. The MEDEX cyclone of 10 June 2000, also known as the Montserrat Case, is a suitable testbed to compare the performance of each ensemble and the PV-satellite method. This case is characterized by an Atlantic upper-level trough and low-level cold front which generated a stationary mesoscale cyclone over the Spanish Mediterranean coast, advecting warm and moist air toward Catalonia from the Mediterranean Sea. The consequences of the resulting mesoscale convective system were 6-h accumulated rainfall amounts of 180 mm with estimated material losses to exceed 65 million euros by media. The performace of both ensemble forecasting systems and PV-satellite technique for our case study is evaluated through the verification of the rainfall field. Since the EPSs are probabilistic forecasts and the PV-satellite is deterministic, their comparison is done using the individual ensemble members. Therefore the verification procedure uses deterministic scores, like the ROC curve, the Taylor diagram or the Q-Q plot. These scores cover the different quality attributes of the forecast such as reliability, resolution, uncertainty and sharpness. The results show that the PV-satellite technique performance lies within the performance range obtained by both ensembles; it is even better than the non-perturbed ensemble member. Thus, perturbing randomly using the PV error climatology and introducing the perturbations in the zones given by each EPS captures the mismatch between PV and WV fields better than manual perturbations made by an expert forecaster, at least for this case study.

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. [74 FR 26536, June 3, 2009] ...

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. [74 FR 26536, June 3, 2009] ...

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. [74 FR 26536, June 3, 2009] ...

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. [74 FR 26536, June 3, 2009] ...

2015 IECRE: PV System Certification Workshop | Photovoltaic Research | NREL

Science.gov Websites

IECRE: PV System Certification Workshop 2015 IECRE: PV System Certification Workshop Thursday the guidelines for certifying PV systems. This workshop included an introduction of IECRE followed by discussions targeting the most critical or controversial items. This workshop gathered wide input from the PV

PV Module Reliability Workshop | Photovoltaic Research | NREL

Science.gov Websites

-year old PV system in Quebec, Canada-Alex Bradley, Tanya Dhir, Yves Poissant Solar panel design factors PV Module Reliability Workshop PV Module Reliability Workshop Tuesday, February 24, 2015 Chair : Michael Kempe The 2015 PV Module Reliability Workshop (PVMRW) continued in the tradition of this annual

40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. [74 FR 26536, June 3, 2009] ...

Effect of wind speed on performance of a solar-pv array

USDA-ARS?s Scientific Manuscript database

Thousands of solar photovoltaic (PV) arrays have been installed over the past few years, but the effect of wind speed on the predicted performance of PV arrays is not usually considered by installers. An increase in wind speed will cool the PV array, and the electrical power of the PV modules will ...

Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

NASA Astrophysics Data System (ADS)

Erkaya, Yunus

The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition. The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV modules using a current-voltage (I-V) curve tracer allows the installer to know whether the PV modules are 100% operational. The installed modules can be properly matched to maximize performance. Once installed, the whole system needs to be characterized similarly to detect mismatches, partial shading, or installation damage before energizing the system. This will prevent any reliability issues from the onset and ensure the system efficiency will remain high. A capacitive load is implemented in making I-V curve measurements with the goal of minimizing the curve tracer volume and cost. Additionally, the increase of measurement resolution and accuracy is possible via the use of accurate voltage and current measurement methods and accurate PV models to translate the curves to standard testing conditions. A move from mechanical relays to solid-state MOSFETs improved system reliability while significantly reducing device volume and costs. Finally, emulating PV modules is necessary for testing electrical components of a PV system. PV emulation simplifies and standardizes the tests allowing for different irradiance, temperature and partial shading levels to be easily tested. Proper emulation of PV modules requires an accurate and mathematically simple PV model that incorporates all known system variables so that any PV module can be emulated as the design requires. A non-synchronous buck converter is proposed for the emulation of a single, high-power PV module using traditional silicon devices. With the proof-of-concept working and improvements in efficiency, power density and steady-state errors made, dynamic tests were performed using an inverter connected to the PV emulator. In order to improve the dynamic characteristics, a synchronous buck converter topology is proposed along with the use of advanced GaNFET devices which resulted in very high power efficiency and improved dynamic response characteristics when emulating PV modules.

Lattice preferred orientation development in lower mantle minerals: Implications for seismic anisotropy

NASA Astrophysics Data System (ADS)

Miyagi, L. M.

2011-12-01

Seismic anisotropy in the deep earth likely results from deformation induced texturing (lattice preferred orientation) of polycrystalline rocks in the Earth's interior. Interpreting these anisotropies in terms of the dynamics and deformation structure of the deep earth requires an understanding of the mechanisms that lead to texturing. In high pressure experiments texture can develop during phase transformations, recrystallization, and deformation. Active deformation mechanisms can be constrained by modeling experimental deformation textures with polycrystal plasticity codes. Once the dominant deformation mechanisms are established for the relevant mineral phases, this information can be combined with geodynamic modeling to predict texture and anisotropy development in the Earth's interior. In (Mg,Fe)SiO3 perovskite (Pv), the major mineral phase of the lower mantle, diamond anvil cell deformation textures are consistent with dominant slip on (001) planes in [100], [010] and/or <110> direction (e.g. Wenk et al. 2006; Miyagi et al. 2010a). (Mg,Fe)O magnesiowüstite (Mw) the second most abundant phase in the lower mantle, produces textures consistent with slip on {110}<-110> (e.g. Merkel et al 2002; Long et al. 2009). Although these two phases develop significant texture during deformation experiments, interestingly, the bulk of the lower mantle exhibits very little anisotropy. This lack of anisotropy may be due to deformation by diffusion processes which do not produce texture (e.g. Karato et al. 1995), or to the fact that deformation textures in Pv and Mw produce opposite anisotropies which cancel each other, yielding a nearly isotropic aggregate (Wenk et al. 2006). In the D" region, (Mg,Fe)SiO3 post-perovskite (pPv) is thought to be the major mineral phase. High pressure deformation experiments on MgGeO3 pPv (Okada et al. 2010; Miyagi et al. 2011) and MgSiO3 pPv (Miyagi et al. 2010b) at ambient temperature, as well as MnGeO3 pPv at 2000 K (Hirose et al. 2010), all produce deformation textures consistent with (001) slip. If (001) slip in pPv is used to model deformation and anisotropy development in the D" region, shear wave splitting characterized by fast horizontally polarized shear waves (VSH) and an anti-correlation of P and S waves in the flow direction is produced, consistent with seismic observations (Miyagi et al. 2010b). Modeling texture development for Mw in the D" also produces a similar pattern of anisotropy and when combined with pPv further enforces this seismic signature (Wenk et al. 2011). Wenk, H.-R., et al. (2006), J. Phy. Cond. Matt. 18(25), S933-S947. Miyagi, L. (2010a) Ph.D. Thesis, UC Berkeley. Merkel, S., et al. (2002) JGR, 107(B11), 2271. Long, M., et al. (2006) PEPI, 156, 75-88. Karato, S., et al. (1995) Science, 270(5235), 458-461. Wenk, H.-R., et al. (2006) EPSL 245(1-2) 302-314. Okada, T., et al. (2010) PEPI 180: 195-202. Miyagi, L., et al (2011) Phys. Chem. Min. in press. Miyagi, L., et al. (2010b) Science, 329, 1639-1641. Hirose, K., et al. (2010) GRL, 37, L20302. Wenk, H-R., et al. (2011) EPSL 306: 33-45.

Power Hardware-in-the-Loop Testing of a Smart Distribution System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendoza Carrillo, Ismael; Breaden, Craig; Medley, Paige

This paper presents the results of the third and final phase of the National Renewable Energy Lab (NREL) INTEGRATE demonstration: Smart Distribution. For this demonstration, high penetrations of solar PV and wind energy systems were simulated in a power hardware-in-the-loop set-up using a smart distribution test feeder. Simulated and real DERs were controlled by a real-time control platform, which manages grid constraints under high clean energy deployment levels. The power HIL testing, conducted at NREL's ESIF smart power lab, demonstrated how dynamically managing DER increases the grid's hosting capacity by leveraging active network management's (ANM) safe and reliable control framework.more » Results are presented for how ANM's real-time monitoring, automation, and control can be used to manage multiple DERs and multiple constraints associated with high penetrations of DER on a distribution grid. The project also successfully demonstrated the importance of escalating control actions given how ANM enables operation of grid equipment closer to their actual physical limit in the presence of very high levels of intermittent DER.« less

Cadmium telluride leaching behavior: Discussion of Zeng et al. (2015).

PubMed

Sinha, Parikhit

2015-11-01

Zeng et al. (2015) evaluate the leaching behavior and surface chemistry of II-VI semiconductor materials, CdTe and CdSe, in response to pH and O2. Under agitation in acidic and aerobic conditions, the authors found approximately 3.6%-6.4% (w/w) solubility of Cd content in CdTe in the Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET), and dissolution test, with lower solubility (0.56-0.58%) under agitation in acidic and anoxic conditions. This range is comparable with prior long-term transformation and dissolution testing and bio-elution testing of CdTe (2.3%-4.1% w/w solubility of Cd content in CdTe). The implications for potential leaching behavior of CdTe-containing devices require further data. Since CdTe PV modules contain approximately 0.05% Cd content by mass, the starting Cd content in the evaluation of CdTe-containing devices would be lower by three orders of magnitude than the starting Cd content in the authors' study, and leaching potential would be further limited by the monolithic glass-adhesive laminate-glass structure of the device that encapsulates the semiconductor material. Experimental evaluation of leaching potential of CdTe PV modules crushed by landfill compactor has been conducted, with results of TCLP and WET tests on the crushed material below regulatory limits for Cd. CdTe PV recycling technology has been in commercial operation since 2005 with high yields for semiconductor (95%) and glass (90%) recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of High PV Penetration on the Inter-Area Oscillations in the U.S. Eastern Interconnection

DOE PAGES

You, Shutang; Kou, Gefei; Liu, Yong; ...

2017-03-31

Our study explores the impact of high-photovoltaic (PV) penetration on the inter-area oscillation modes of large-scale power grids. A series of dynamic models with various PV penetration levels are developed based on a detailed model representing the U.S. Eastern Interconnection (EI). Transient simulations are performed to investigate the change of inter-area oscillation modes with PV penetration. The impact of PV control strategies and parameter settings on inter-area oscillations is studied. This paper finds that as PV increases, the damping of the dominant oscillation mode decreases monotonically. We also observed that the mode shape varies with the PV control strategy andmore » new oscillation modes may emerge under inappropriate parameter settings in PV plant controls.« less

Conversion of Fibroblasts to Parvalbumin Neurons by One Transcription Factor, Ascl1, and the Chemical Compound Forskolin*

PubMed Central

Shi, Zixiao; Zhang, Juan; Chen, Shuangquan; Li, Yanxin; Lei, Xuepei; Qiao, Huimin; Zhu, Qianwen; Hu, Baoyang; Zhou, Qi; Jiao, Jianwei

2016-01-01

Abnormalities in parvalbumin (PV)-expressing interneurons cause neurodevelopmental disorders such as epilepsy, autism, and schizophrenia. Unlike other types of neurons that can be efficiently differentiated from pluripotent stem cells, PV neurons were minimally generated using a conventional differentiation strategy. In this study we developed an adenovirus-based transdifferentiation strategy that incorporates an additional chemical compound for the efficient generation of induced PV (iPV) neurons. The chemical compound forskolin combined with Ascl1 induced ∼80% of mouse fibroblasts to iPV neurons. The iPV neurons generated by this procedure matured 5–7 days post infection and were characterized by electrophysiological properties and known neuronal markers, such as PV and GABA. Our studies, therefore, identified an efficient approach for generating PV neurons. PMID:27137935

Whooping cough surveillance in France in pediatric private practice in 2006-2015.

PubMed

Guiso, Nicole; Levy, Corinne; Romain, Olivier; Guillot, Sophie; Werner, Andreas; Rondeau, Marie Charlotte; Béchet, Stéphane; Cohen, Robert

2017-10-27

Increasing incidence of whooping cough (pertussis) has been reported in many countries, attributed to a switch from whole-cell pertussis-containing vaccine (wPV) to acellular PV (aPV) and circulation of the pertactin non-producing Bordetella pertussis. The present study aimed to estimate the duration of immunity conferred by PVs in children in France with data from an ongoing pediatric ambulatory surveillance of pertussis. A total of 64 pediatricians throughout France enrolled children with suspected pertussis. A standardized data form was used to collect data on age sex, vaccination status, brand of wPV or aPV and source of infection. Confirmed cases were positive on culture and/or real-time Polymerase Chain Reaction (for B.-non-classified or B. pertussis or B. parapertussis) and/or pertussis serology. Between October 2006 and December 2015, 149 cases of confirmed Bordetella infections were reported, 86 infected with B. pertussis and 55 B. non-classified. Fifteen children (10.1%) were not vaccinated, and 26 (17.4%) were partially vaccinated. The mean age was greater for children who received 4 doses of wPV (11.3±2.2, p<0.001) or a combination of wPV and aPV (10.5±3.3, p<0.001) than only aPV (7.2±2.4years). The mean duration of cough before a visit to a pediatrician was longer for children with wPV or a combination of wPV and aPV than only aPV (23.8±10.1 and 25.0±25.6vs 13.6±10.0days). Despite the use of a more sensitive diagnostic method and emergence of pertactin non producing B. pertussis, in France context, aPV-induced immunity still protects against pertussis; however, the mean duration of immunity is about 6 to 7years, compared to 9years for wPV vaccine, after the primary vaccination and one booster (3+1 doses). Copyright © 2017 Elsevier Ltd. All rights reserved.

Origin of the Outbreak in France of Pseudomonas syringae pv. actinidiae Biovar 3, the Causal Agent of Bacterial Canker of Kiwifruit, Revealed by a Multilocus Variable-Number Tandem-Repeat Analysis.

PubMed

Cunty, A; Cesbron, S; Poliakoff, F; Jacques, M-A; Manceau, C

2015-10-01

The first outbreaks of bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae biovar 3 were detected in France in 2010. P. syringae pv. actinidiae causes leaf spots, dieback, and canker that sometimes lead to the death of the vine. P. syringae pv. actinidifoliorum, which is pathogenic on kiwi as well, causes only leaf spots. In order to conduct an epidemiological study to track the spread of the epidemics of these two pathogens in France, we developed a multilocus variable-number tandem-repeat (VNTR) analysis (MLVA). MLVA was conducted on 340 strains of P. syringae pv. actinidiae biovar 3 isolated in Chile, China, France, Italy, and New Zealand and on 39 strains of P. syringae pv. actinidifoliorum isolated in Australia, France, and New Zealand. Eleven polymorphic VNTR loci were identified in the genomes of P. syringae pv. actinidiae biovar 3 ICMP 18744 and of P. syringae pv. actinidifoliorum ICMP 18807. MLVA enabled the structuring of P. syringae pv. actinidiae biovar 3 and P. syringae pv. actinidifoliorum strains in 55 and 16 haplotypes, respectively. MLVA and discriminant analysis of principal components revealed that strains isolated in Chile, China, and New Zealand are genetically distinct from P. syringae pv. actinidiae strains isolated in France and in Italy, which appear to be closely related at the genetic level. In contrast, no structuring was observed for P. syringae pv. actinidifoliorum. We developed an MLVA scheme to explore the diversity within P. syringae pv. actinidiae biovar 3 and to trace the dispersal routes of epidemic P. syringae pv. actinidiae biovar 3 in Europe. We suggest using this MLVA scheme to trace the dispersal routes of P. syringae pv. actinidiae at a global level. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

The influence of emotional stress on Doppler-derived aortic peak velocity in boxer dogs.

PubMed

Pradelli, D; Quintavalla, C; Crosta, M C; Mazzoni, L; Oliveira, P; Scotti, L; Brambilla, P; Bussadori, C

2014-01-01

Subaortic stenosis (SAS) is a common congenital heart disease in Boxers. Doppler-derived aortic peak velocity (AoPV) is a diagnostic criterion for the disease. To investigate the influence of emotional stress during echocardiographic examination on AoPV in normal and SAS-affected Boxers. To evaluate the effects of aortic root diameters on AoPV in normal Boxers. DOGS: Two hundred and fifteen normal and 19 SAS-affected Boxers. The AoPV was recorded at the beginning of echocardiographic examination (T0), and when the emotional stress of the dog was assumed to decrease based on behavioral parameters and heart rate (T1). AoPV0-AoPV1 was calculated. In normal dogs, stroke volume index was calculated at T0 and T1. Aortic root diameters were measured and their relationship with AoPV and AoPV0-AoPV1 was evaluated. In normal dogs, AoPV was higher at T0 (median, 1.95 m/s; range, 1.60-2.50 m/s) than at T1 (median, 1.76 m/s; range, 1.40-2.20 m/s; P < .0001; reduction 9.2%). The stroke volume index at T0 also was greater than at T1 (P < .0001). Weak negative correlations were detected between aortic root size and aortic velocities. In SAS-affected dogs, AoPV0 was higher than AoPV1 (P < .0001; reduction 7.3%). Aortic peak velocity was affected by emotional stress during echocardiographic examination both in SAS-affected and normal Boxers. In normal Boxers, aortic root size weakly affected AoPVs, but did not affect AoPV0-AoPV1. Stroke volume seems to play a major role in stress-related AoPV increases in normal Boxers. Emotional stress should be taken into account when screening for SAS in the Boxer breed. Copyright © 2014 by the American College of Veterinary Internal Medicine.

DOE and AID stand-alone photovoltaic activities

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Ratajczak, A. F.

1983-01-01

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system activities sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, PV-powered medical refrigerators in six countries, PV system microprocessor control development activities and PV-hybrid system assessments. The AID project includes a large village system in Tunisia, a water pumping/grain grinding project in Upper Volta, five medical clinics in four countries, PV-powered remote earth station application. These PV activities and summarizes significant findings to data are reviewed.

Photovoltaic electricity generation: Value for residential and commercial sectors

NASA Astrophysics Data System (ADS)

Bhattacharjee, Ujjwal

The photovoltaic (PV) industry in the US has seen an upsurge in recent years, and PV holds great promise as a renewable technology with no greenhouse gas emissions with its use. We aim to assess the value of PV based electricity for users in the residential and commercial sectors focusing on the financial impacts it has, which may not be greatly recognized. Specifically, we pursue two goals. First, the emerging 'renewable portfolio standard (RPS)' adopted in several states in the country has been a driving force for large scale PV deployment, but financial incentives offered to PV in different RPS states differ considerably. We use life cycle cost model to estimate the cost of PV based electricity for thirty-two RPS states in the country. Results indicate that the levelized cost of PV electricity is high (40 to 60 Cents/kWh). When the contribution of the financial incentives (along with the cost of energy saved) is taken into account, the cost of PV based electricity is negative in some RPS states such as California, New Jersey, New York, while for most of the RPS states the cost of PV electricity continues to remain high. In addition, the states with negative or low cost of PV electricity have been driving the PV diffusion in the residential sector. Therefore, a need to adjust the financial incentive structure in different RPS states is recommended for homogenous development of the residential PV market in the country. Second, we assess the value of the PV in reducing the highest peak load demand in commercial buildings and hence the high value demand charge. The Time-of-Use (TOU) based electricity tariff is widely used by electric utilities in the commercial sector. Energy and peak load are two important facets of the TOU tariff regime. Tools are well established to estimate the energy contribution from a PV system (installed in a commercial building), but not power output on a short time interval. A joint conditional probability model has been developed that enables estimation of the PV contribution towards the peak load reduction for a given high building load. Results indicate a significant cost saving (15% to 40%) with application of the model. This will encourage commercial entities (building owners) to adopt PV as a distributed energy source. The tool would be useful for energy modelers and green building architects as it will enable them to estimate cost savings due to PV deployment in commercial buildings. Moreover, the model tested for three different commercial buildings indicates that school buildings show the best promise for PV deployment followed, respectively, by office buildings and manufacturing facilities. This will help PV incentive programs in the country to use resources effectively to enhance the diffusion of PV in the commercial sector.

Loss of local capture of the pulmonary vein myocardium after antral isolation: prevalence and clinical significance.

PubMed

Squara, Fabien; Liuba, Ioan; Chik, William; Santangeli, Pasquale; Zado, Erica S; Callans, David J; Marchlinski, Francis E

2015-03-01

Capture of the myocardial sleeves of the pulmonary veins (PV) during PV pacing is mandatory for assessing exit block after PV isolation (PVI). However, previous studies reported that a significant proportion of PVs failed to demonstrate local capture after PVI. We designed this study to evaluate the prevalence and the clinical significance of loss of PV capture after PVI. Thirty patients (14 redo) undergoing antral PVI were included. Before and after PVI, local PV capture was assessed during circumferential pacing (10 mA/2 milliseconds) with a circular multipolar catheter (CMC), using EGM analysis from each dipole of the CMC and from the ablation catheter placed in ipsilateral PV. Pacing output was varied to optimize identification of sleeve capture. All PVs demonstrated sleeve capture before PVI, but only 81% and 40% after first time and redo PVI, respectively (P < 0.001 vs. before PVI). In multivariate analysis, absence of spontaneous PV depolarizations after PVI and previous PVI procedures were associated with less PV sleeve capture after PVI (40% sleeve capture, P < 0.001 for both). Loss of PV local capture by design was coincident with the development of PV entrance block and importantly predicted absence of acute reconnection during adenosine challenge with 96% positive predictive value (23% negative predictive value). Loss of PV local capture is common after antral PVI resulting in entrance block, and may be used as a specific alternate endpoint for PV electrical isolation. Additionally, loss of PV local capture may identify PVs at very low risk of acute reconnection during adenosine challenge. © 2014 Wiley Periodicals, Inc.

PV water pumping: NEOS Corporation recent PV water pumping activities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lane, C.

1995-11-01

NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature publishedmore » by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.« less

The Value of Transparency in Distributed Solar PV Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J; Zamzam, Ahmed S

Market transparency refers to the degree of customer awareness of product options and fair market prices for a given good. In The Value of Transparency in Distributed Solar PV Markets, we use residential solar photovoltaic (PV) quote data to study the value of transparency in distributed solar PV markets. We find that improved market transparency results in lower installation offer prices. Further, the results of this study suggest that PV customers benefit from gaining access to more PV quotes.

PV Working with Industry, 2nd Quarter, 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poole, L.; Moon, S.

2000-06-29

NREL PV Working With Industry is a quarterly newsletter devoted to the research, development, and deployment performed by NREL staff in concert with their industry and university partners. The Second Quarter, 2000, issue is titled ``Our Shared PV Future''. It contains a review of several important PV-related meetings held in the prior three months: the NCPV Program Review, the 16 European PV Conference, and year-2000 Earth Day activities in Denver, CO. The editorialist is Paul Maycock, Publisher of PV News.

Sensitivity of Rooftop PV Projections in the SunShot Vision Study to Market Assumptions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drury, E.; Denholm, P.; Margolis, R.

2013-01-01

The SunShot Vision Study explored the potential growth of solar markets if solar prices decreased by about 75% from 2010 to 2020. The SolarDS model was used to simulate rooftop PV demand for this study, based on several PV market assumptions--future electricity rates, customer access to financing, and others--in addition to the SunShot PV price projections. This paper finds that modeled PV demand is highly sensitive to several non-price market assumptions, particularly PV financing parameters.

Leasing Into the Sun: A Mixed Method Analysis of Transactions of Homes with Third Party Owned Solar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoen, Ben; Rand, Joseph; Adomatis, Sandra

This analysis is the first to examine if homes with third-party owned (TPO) PV systems are unique in the marketplace as compared to non-PV or non-TPO PV homes. This is of growing importance as the number of homes with TPO systems is nearly a half of a million in the US currently and is growing. A hedonic pricing model analysis of 20,106 homes that sold in California between 2011 and 2013 is conducted, as well as a paired sales analysis of 18 pairs of TPO PV and non-PV homes in San Diego spanning 2012 and 2013. The hedonic model examinedmore » 2,914 non-TPO PV home sales and 113 TPO PV sales and fails to uncover statistically significant premiums for TPO PV homes nor for those with pre-paid leases as compared to non-PV homes. Similarly, the paired sales analysis does not find evidence of an impact to value for the TPO homes when comparing to non-PV homes. Analyses of non-TPO PV sales both here and previously have found larger and statistically significant premiums. Collection of a larger dataset that covers the present period is recommended for future analyses so that smaller, more nuanced and recent effects can be discovered.« less

Correlation between portal vein anatomy and bile duct variation in 407 living liver donors.

PubMed

Takeishi, K; Shirabe, K; Yoshida, Y; Tsutsui, Y; Kurihara, T; Kimura, K; Itoh, S; Harimoto, N; Yamashita, Y-I; Ikegami, T; Yoshizumi, T; Nishie, A; Maehara, Y

2015-01-01

Our aim was to determine whether variant bile duct (BD) anatomy is associated with portal vein (PV) and/or hepatic artery (HA) anatomy. We examined the associations between BD anatomy and PV and/or HA anatomy in 407 living donor transplantation donors. We also examined whether the right posterior BD (RPBD) course was associated with the PV and/or HA anatomy. Variant PV, HA and BD anatomies were found in 11%, 25% and 25%, respectively, of 407 donors enrolled in this study. The presence of a variant BD was more frequently associated with a variant PV than with a normal PV (61% vs. 20%, p < 0.0001). By contrast, the presence of a variant HA was not associated with a variant BD. A supraportal RPBD was found in 357 donors (88%) and an infraportal RPBD was found in 50 donors (12%). An infraportal RPBD was significantly more common in donors with a variant PV than in donors with a normal PV (30% vs. 10%, p = 0.0004). Variant PV, but not variant HA, anatomies were frequently associated with variant BD anatomy. Additionally, an infraportal RPBD was more common in donors with a variant PV than in donors with a normal PV. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

The development and performance of smud grid-connected photovoltaic projects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osborn, D.E.; Collier, D.E.

1995-11-01

The utility grid-connected market has been identified as a key market to be developed to accelerate the commercialization of photovoltaics. The Sacramento Municipal Utility District (SMUD) has completed the first two years of a continuing commercialization effort based on two years of a continuing commercialization effort based on the sustained, orderly development of the grid-connected, utility PV market. This program is aimed at developing the experience needed to successfully integrate PV as distributed generation into the utility system and to stimulate the collaborative processes needed to accelerate the cost reductions necessary for PV to be cost-effective in these applications bymore » the year 2000. In the first two years, SMUD has installed over 240 residential and commercial building, grid-connected, rooftop, {open_quotes}PV Pioneer{close_quotes} systems totaling over 1MW of capacity and four substation sited, grid-support PV systems totaling 600 kW bringing the SMUD distributed PV power systems to over 3.7 MW. The 1995 SMUD PV Program will add another approximately 800 kW of PV systems to the District`s distributed PV power system. SMUD also established a partnership with its customers through the PV Pioneer {open_quotes}green pricing{close_quotes} program to advance PV commercialization.« less

Photovoltaic-Model-Based Solar Irradiance Estimators: Performance Comparison and Application to Maximum Power Forecasting

NASA Astrophysics Data System (ADS)

Scolari, Enrica; Sossan, Fabrizio; Paolone, Mario

2018-01-01

Due to the increasing proportion of distributed photovoltaic (PV) production in the generation mix, the knowledge of the PV generation capacity has become a key factor. In this work, we propose to compute the PV plant maximum power starting from the indirectly-estimated irradiance. Three estimators are compared in terms of i) ability to compute the PV plant maximum power, ii) bandwidth and iii) robustness against measurements noise. The approaches rely on measurements of the DC voltage, current, and cell temperature and on a model of the PV array. We show that the considered methods can accurately reconstruct the PV maximum generation even during curtailment periods, i.e. when the measured PV power is not representative of the maximum potential of the PV array. Performance evaluation is carried out by using a dedicated experimental setup on a 14.3 kWp rooftop PV installation. Results also proved that the analyzed methods can outperform pyranometer-based estimations, with a less complex sensing system. We show how the obtained PV maximum power values can be applied to train time series-based solar maximum power forecasting techniques. This is beneficial when the measured power values, commonly used as training, are not representative of the maximum PV potential.

Electricity Bill Savings from Residential Photovoltaic Systems: Sensitivities to Changes in Future Electricity Market Conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darghouth, Naim; Barbose, Galen; Wiser, Ryan

2013-01-09

Customer-sited photovoltaic (PV) systems in the United States are often compensated at the customer’s underlying retail electricity rate through net metering. Calculations of the customer economics of PV, meanwhile, often assume that retail rate structures and PV compensation mechanisms will not change and that retail electricity prices will increase (or remain constant) over time, thereby also increasing (or keeping constant) the value of bill savings from PV. Given the multitude of potential changes to retail rates and PV compensation mechanisms in the future, however, understanding how such changes might impact the value of bill savings from PV is critical formore » policymakers, regulators, utilities, the solar industry, and potential PV owners, i.e., any stakeholder interested in understanding uncertainties in and potential changes to the long-term customer economics of PV. This scoping study investigates the impact of, and interactions among, three key sources of uncertainty in the future value of bill savings from customer-sited PV, focusing in particular on residential customers. These three sources of uncertainty are: changes to electricity market conditions that would affect retail electricity prices, changes to the types of retail rate structures available to residential customers with PV, and shifts away from standard net-metering toward other compensation mechanisms for residential PV.« less

Easy and fast method for expression and native extraction of Plasmodium vivax Duffy binding protein fragments.

PubMed

Moreno-Pérez, Darwin Andrés; Baquero, Luis Alfredo; Bermúdez, Maritza; Gómez-Muñoz, Laura Alejandra; Varela, Yahson; Patarroyo, Manuel Alfonso

2018-02-08

The Plasmodium vivax Duffy binding protein (PvDBP) has been the most studied ligand binding human reticulocytes to date. This molecule has a cysteine-rich domain in region II (RII) which has been used as control for evaluating the target cell binding activity of several parasite molecules. However, obtaining rPvDBP-RII in a soluble form using the Escherichia coli expression system usually requires laborious and time-consuming steps for recovering the molecule's structure and function, considering it is extracted from inclusion bodies. The present study describes an easy and fast method for expressing and obtaining several PvDBP fragments which should prove ideal for use in protein-cell interaction assays. Two PvDBP encoding regions (rii and riii/v) were cloned in pEXP5-CT vector and expressed in E. coli and extracted from the soluble fraction (rPvDBP-RII S and rPvDBP-RIII/V S ) using a simple freezing/thawing protocol. After the purification, dichroism analysis enabled verifying high rPvDBP-RII S and rPvDBP-RIII/V S secondary structure α-helix content, which was lowered when molecules were extracted from inclusion bodies (rPvDBP-RII IB and rPvDBP-RIII/V IB ) using a denaturing step. Interestingly, rPvDBP-RII S , but not rPvDBP-RII IB , bound to human reticulocytes, while rPvDBP-RIII/V S and rPvDBP-RIII/V IB bound to such cells in a similar way to negative control (cells incubated without recombinant proteins). This research has shown for the first time how rPvDBP-RII can be expressed and obtained in soluble form using the E. coli system and avoiding the denaturation and refolding steps commonly used. The results highlight the usefulness of the rPvDBP-RIII/V S fragment as a non-binding control for protein-cell target interaction assays. The soluble extraction protocol described is a good alternative to obtain fully functional P. vivax proteins in a fast and easy way, which will surely prove useful to laboratories working in studying this parasite's biology.

Muscarinic excitation of parvalbumin-positive interneurons contributes to the severity of pilocarpine-induced seizures

PubMed Central

Yi, Feng; DeCan, Evan; Stoll, Kurt; Marceau, Eric; Deisseroth, Karl; Lawrence, J. Josh

2014-01-01

SUMMARY Objective A common rodent model in epilepsy research employs the muscarinic acetylcholine receptor (mAChR) agonist pilocarpine, yet the mechanisms underlying the induction of pilocarpine-induced seizures (PISs) remain unclear. Global M1 mAChR (M1R) knockout mice are resistant to PISs, implying that M1R activation disrupts excitation/inhibition balance. Parvalbumin-positive (PV) inhibitory neurons express M1 mAChRs, participate in cholinergically-induced oscillations, and can enter a state of depolarization block (DB) during epileptiform activity. Here, we test the hypothesis that pilocarpine activation of M1Rs expressed on PV cells contributes to PISs. Methods CA1 PV cells in PV-CRE mice were visualized with a floxed YFP or hM3Dq-mCherry adeno-associated virus, or by crossing PV-CRE mice with the RosaYFP reporter line. To eliminate M1Rs from PV cells, we generated PV-M1KO mice by crossing PV-CRE and floxed M1 mice. Action potential (AP) frequency was monitored during application of pilocarpine (200 µM). In behavioral experiments, locomotion and seizure symptoms were recorded in WT or PV-M1KO mice during PISs. Results Pilocarpine significantly increased AP frequency in CA1 PV cells into the gamma range. In the continued presence of pilocarpine, a subset (5/7) of PV cells progressed to DB, which was mimicked by hM3Dq activation of Gq-receptor signaling. Pilocarpine-induced depolarization, AP firing at gamma frequency, and progression to DB were prevented in CA1 PV cells of PV-M1KO mice. Finally, compared to WT mice, PV-M1KO mice were associated with reduced severity of PISs. Significance Pilocarpine can directly depolarize PV+ cells via M1R activation but a subset of these cells progress to DB. Our electrophysiological and behavioral results suggest that this mechanism is active during PISs, contributing to a collapse of PV-mediated GABAergic inhibition, dysregulation of excitation/inhibition balance, and increased susceptibility to PISs. PMID:25495999

NREL to Host Ninth Annual PV Reliability Workshop | News | NREL

Science.gov Websites

share research leading to more durable and reliable PV modules, thus reducing the cost of solar to Host Ninth Annual PV Reliability Workshop NREL to Host Ninth Annual PV Reliability Workshop their results during a poster session at the 2017 PV Reliability Workshop. 4 people consult two

Photovoltaics as a terrestrial energy source. Volume 3: An overview

NASA Technical Reports Server (NTRS)

Smith, J. L.

1980-01-01

Photovoltaic (PV) systems were evaluated in terms of their potential for terrestrial application A comprehensive overview of important issues which bear on photovoltaic (PV) systems development is presented. Studies of PV system costs, the societal implications of PV system development, and strategies in PV research and development in relationship to current energy policies are summarized.

Solar Photovoltaic DC Systems: Basics and Safety: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNutt, Peter F; Sekulic, William R; Dreifuerst, Gary

Solar Photovoltaic (PV) systems are common and growing with 42.4 GW installed capacity in U.S. (almost 15 GW added in 2016). This paper will help electrical workers, and emergency responders understand the basic operating principles and hazards of PV DC arrays. We briefly discuss the following aspects of solar photovoltaic (PV) DC systems: the effects of solar radiation and temperature on output power; PV module testing standards; common system configurations; a simple PV array sizing example; NEC guidelines and other safety features; DC array commissioning, periodic maintenance and testing; arc-flash hazard potential; how electrical workers and emergency responders can andmore » do work safely around PV arrays; do moonlight and artificial lighting pose a real danger; typical safe operating procedures; and other potential DC-system hazards to be aware of. We also present some statistics on PV DC array electrical incidents and injuries. Safe PV array operation is possible with a good understanding of PV DC arrays basics and having good safe operating procedures in place.« less

Research on Fault Characteristics and Line Protections Within a Large-scale Photovoltaic Power Plant

NASA Astrophysics Data System (ADS)

Zhang, Chi; Zeng, Jie; Zhao, Wei; Zhong, Guobin; Xu, Qi; Luo, Pandian; Gu, Chenjie; Liu, Bohan

2017-05-01

Centralized photovoltaic (PV) systems have different fault characteristics from distributed PV systems due to the different system structures and controls. This makes the fault analysis and protection methods used in distribution networks with distributed PV not suitable for a centralized PV power plant. Therefore, a consolidated expression for the fault current within a PV power plant under different controls was calculated considering the fault response of the PV array. Then, supported by the fault current analysis and the on-site testing data, the overcurrent relay (OCR) performance was evaluated in the collection system of an 850 MW PV power plant. It reveals that the OCRs at downstream side on overhead lines may malfunction. In this case, a new relay scheme was proposed using directional distance elements. In the PSCAD/EMTDC, a detailed PV system model was built and verified using the on-site testing data. Simulation results indicate that the proposed relay scheme could effectively solve the problems under variant fault scenarios and PV plant output levels.

Analysis of high voltage step-up nonisolated DC-DC boost converters

NASA Astrophysics Data System (ADS)

Alisson Alencar Freitas, Antônio; Lessa Tofoli, Fernando; Junior, Edilson Mineiro Sá; Daher, Sergio; Antunes, Fernando Luiz Marcelo

2016-05-01

A high voltage step-up nonisolated DC-DC converter based on coupled inductors suitable to photovoltaic (PV) systems applications is proposed in this paper. Considering that numerous approaches exist to extend the voltage conversion ratio of DC-DC converters that do not use transformers, a detailed comparison is also presented among the proposed converter and other popular topologies such as the conventional boost converter and the quadratic boost converter. The qualitative analysis of the coupled-inductor-based topology is developed so that a design procedure can be obtained, from which an experimental prototype is implemented to validate the theoretical assumptions.

Deletion of metallothionein exacerbates intermittent hypoxia-induced oxidative and inflammatory injury in aorta.

PubMed

Zhou, Shanshan; Wang, Yonggang; Tan, Yi; Cai, Xiaohong; Cai, Lu; Cai, Jun; Zheng, Yang

2014-01-01

The present study was to explore the effect of metallothionein (MT) on intermittent hypoxia (IH) induced aortic pathogenic changes. Markers of oxidative damages, inflammation, and vascular remodeling were observed by immunohistochemical staining after 3 days and 1, 3, and 8 weeks after IH exposures. Endogenous MT was induced after 3 days of IH but was significantly decreased after 8 weeks of IH. Compared with the wild-type mice, MT knock-out mice exhibited earlier and more severe pathogenic changes of oxidative damages, inflammatory responses, and cellular apoptosis, as indicated by the significant accumulation of collagen, increased levels of connective tissue growth factor, transforming growth factor β1, tumor necrosis factor-alpha, vascular cell adhesion molecule 1,3-nitrotyrosine, and 4-hydroxy-2-nonenal in the aorta. These findings suggested that chronic IH may lead to aortic damages characterized by oxidative stress and inflammation, and MT may play a pivotal role in the above pathogenesis process.

Macroscopic inhomogeneous deformation behavior arising in single crystal Ni-Mn-Ga foils under tensile loading

NASA Astrophysics Data System (ADS)

Murasawa, Go; Yeduru, Srinivasa R.; Kohl, Manfred

2016-12-01

This study investigated macroscopic inhomogeneous deformation occurring in single-crystal Ni-Mn-Ga foils under uniaxial tensile loading. Two types of single-crystal Ni-Mn-Ga foil samples were examined as-received and after thermo-mechanical training. Local strain and the strain field were measured under tensile loading using laser speckle and digital image correlation. The as-received sample showed a strongly inhomogeneous strain field with intermittence under progressive deformation, but the trained sample result showed strain field homogeneity throughout the specimen surface. The as-received sample is a mainly polycrystalline-like state composed of the domain structure. The sample contains many domain boundaries and large domain structures in the body. Its structure would cause large local strain band nucleation with intermittence. However, the trained one is an ideal single-crystalline state with a transformation preferential orientation of variants after almost all domain boundary and large domain structures vanish during thermo-mechanical training. As a result, macroscopic homogeneous deformation occurs on the trained sample surface during deformation.

Coordinated distribution network control of tap changer transformers, capacitors and PV inverters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceylan, Oğuzhan; Liu, Guodong; Tomsovic, Kevin

A power distribution system operates most efficiently with voltage deviations along a feeder kept to a minimum and must ensure all voltages remain within specified limits. Recently with the increased integration of photovoltaics, the variable power output has led to increased voltage fluctuations and violation of operating limits. This study proposes an optimization model based on a recently developed heuristic search method, grey wolf optimization, to coordinate the various distribution controllers. Several different case studies on IEEE 33 and 69 bus test systems modified by including tap changing transformers, capacitors and photovoltaic solar panels are performed. Simulation results are comparedmore » to two other heuristic-based optimization methods: harmony search and differential evolution. Finally, the simulation results show the effectiveness of the method and indicate the usage of reactive power outputs of PVs facilitates better voltage magnitude profile.« less

Coordinated distribution network control of tap changer transformers, capacitors and PV inverters

DOE PAGES

Ceylan, Oğuzhan; Liu, Guodong; Tomsovic, Kevin

2017-06-08

A power distribution system operates most efficiently with voltage deviations along a feeder kept to a minimum and must ensure all voltages remain within specified limits. Recently with the increased integration of photovoltaics, the variable power output has led to increased voltage fluctuations and violation of operating limits. This study proposes an optimization model based on a recently developed heuristic search method, grey wolf optimization, to coordinate the various distribution controllers. Several different case studies on IEEE 33 and 69 bus test systems modified by including tap changing transformers, capacitors and photovoltaic solar panels are performed. Simulation results are comparedmore » to two other heuristic-based optimization methods: harmony search and differential evolution. Finally, the simulation results show the effectiveness of the method and indicate the usage of reactive power outputs of PVs facilitates better voltage magnitude profile.« less

Impacts of the transformation of the German energy system on the transmission grid

NASA Astrophysics Data System (ADS)

Pesch, T.; Allelein, H.-J.; Hake, J.-F.

2014-10-01

The German Energiewende, the transformation of the energy system, has deep impacts on all parts of the system. This paper presents an approach that has been developed to simultaneously analyse impacts on the energy system as a whole and on the electricity system in particular. In the analysis, special emphasis is placed on the transmission grid and the efficiency of recommended grid extensions according to the German Network Development Plan. The analysis reveals that the measures in the concept are basically suitable for integrating the assumed high share of renewables in the future electricity system. Whereas a high feed-in from PV will not cause problems in the transmission grid in 2022, congestion may occur in situations with a high proportion of wind feed-in. Moreover, future bottlenecks in the grid are located in the same regions as today.

How PV system ownership can impact the market value of residential homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Johnson, Jamie L.

2014-01-01

There are multiple ways for a homeowner to obtain the electricity generating and savings benefits offered by a photovoltaic (PV) system. These include purchasing a PV system through various financing mechanisms, or by leasing the PV system from a third party with multiple options that may include purchase, lease renewal or PV system removal. The different ownership options available to homeowners presents a challenge to appraisal and real estate professionals during a home sale or refinance in terms of how to develop a value that is reflective of the PV systems operational characteristics, local market conditions, and lender and underwritermore » requirements. This paper presents these many PV system ownership options with a discussion of what considerations an appraiser must make when developing the contributory value of a PV system to a residential property.« less

Feline papillomas and papillomaviruses.

PubMed

Sundberg, J P; Van Ranst, M; Montali, R; Homer, B L; Miller, W H; Rowland, P H; Scott, D W; England, J J; Dunstan, R W; Mikaelian, I; Jenson, A B

2000-01-01

Papillomaviruses (PVs) are highly species- and site-specific pathogens of stratified squamous epithelium. Although PV infections in the various Felidae are rarely reported, we identified productive infections in six cat species. PV-induced proliferative skin or mucous membrane lesions were confirmed by immunohistochemical screening for papillomavirus-specific capsid antigens. Seven monoclonal antibodies, each of which reacts with an immunodominant antigenic determinant of the bovine papillomavirus L1 gene product, revealed that feline PV capsid epitopes were conserved to various degrees. This battery of monoclonal antibodies established differential expression patterns among cutaneous and oral PVs of snow leopards and domestic cats, suggesting that they represent distinct viruses. Clinically, the lesions in all species and anatomic sites were locally extensive and frequently multiple. Histologically, the areas of epidermal hyperplasia were flat with a similarity to benign tumors induced by cutaneotropic, carcinogenic PVs in immunosuppressed human patients. Limited restriction endonuclease analyses of viral genomic DNA confirmed the variability among three viral genomes recovered from available frozen tissue. Because most previous PV isolates have been species specific, these studies suggest that at least eight different cat papillomaviruses infect the oral cavity (tentative designations: Asian lion, Panthera leo, P1PV; snow leopard, Panthera uncia, PuPV-1; bobcat, Felis rufus, FrPV; Florida panther, Felis concolor, FcPV; clouded leopard, Neofelis nebulosa, NnPV; and domestic cat, Felis domesticus, FdPV-2) or skin (domestic cat, F. domesticus, FdPV-1; and snow leopard, P. uncia, PuPV-2).

Coagulation activation in autoimmune bullous diseases

PubMed Central

Marzano, A V; Tedeschi, A; Spinelli, D; Fanoni, D; Crosti, C; Cugno, M

2009-01-01

The main autoimmune blistering skin disorders are pemphigus vulgaris (PV) and bullous pemphigoid (BP). They differ in the inflammatory infiltrate, which is more intense in BP. Inflammation is known to activate coagulation in several disorders. Local and systemic activation of coagulation was evaluated in BP and PV. We studied 20 BP patients (10 active and 10 remittent), 23 PV patients (13 active and 10 remittent) and 10 healthy subjects. The coagulation markers prothrombin fragment F1+2 and D-dimer were measured by enzyme-immunoassays in plasma. The presence of tissue factor (TF), the main initiator of blood coagulation, was evaluated immunohistochemically in skin specimens from 10 patients with active PV, 10 patients with active BP and 10 controls. Plasma F1+2 and D-dimer levels were significantly high in active BP (P = 0·001), whereas in active PV the levels were normal. During remission, F1+2 and D-dimer plasma levels were normal in both BP and PV. TF immunoreactivity was found in active BP but neither in active PV nor in normal skin. TF reactivity scores were higher in active BP than in controls or active PV (P = 0·0001). No difference in TF scores was found between active PV and controls. BP is associated with coagulation activation, which is lacking in PV. This suggests that BP but not PV patients have an increased thrombotic risk. The observation that thrombotic complications occur more frequently in BP than in PV further supports this view. PMID:19737228

To Own or Lease Solar: Understanding Commercial Retailers' Decisions to Use Alternative Financing Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feldman, David; Margolis, Robert

This report examines the tradeoffs among financing methods for businesses installing onsite photovoltaics (PV). We present case studies of PV financing strategies used by two large commercial retailers that have deployed substantial U.S. PV capacity: IKEA, which owns its PV, and Staples, which purchases power generated from onsite PV systems through power purchase agreements (PPAs). We also analyze the financial considerations that influence any company's choice of PV financing strategy. Our goal in this report is to clarify the financial and institutional costs and benefits of financing strategies and to inform other companies that are considering launching or expanding similarmore » PV programs.« less

2015 PV Solar Resource Workshop | Photovoltaic Research | NREL

Science.gov Websites

PV Solar Resource Workshop 2015 PV Solar Resource Workshop Friday, February 27, 2015 Chairs understand the solar resource available to PV plants and opportunities for the community to improve over the as Adobe Acrobat PDFs. Solar Resource Needs for Prediction and Monitoring of PV Performance

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions

PubMed Central

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C.

2015-01-01

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper. PMID:26230694

A Decentralized Wireless Solution to Monitor and Diagnose PV Solar Module Performance Based on Symmetrized-Shifted Gompertz Functions.

PubMed

Molina-García, Angel; Campelo, José Carlos; Blanc, Sara; Serrano, Juan José; García-Sánchez, Tania; Bueso, María C

2015-07-29

This paper proposes and assesses an integrated solution to monitor and diagnose photovoltaic (PV) solar modules based on a decentralized wireless sensor acquisition system. Both DC electrical variables and environmental data are collected at PV module level using low-cost and high-energy efficiency node sensors. Data is real-time processed locally and compared with expected PV module performances obtained by a PV module model based on symmetrized-shifted Gompertz functions (as previously developed and assessed by the authors). Sensor nodes send data to a centralized sink-computing module using a multi-hop wireless sensor network architecture. Such integration thus provides extensive analysis of PV installations, and avoids off-line tests or post-processing processes. In comparison with previous approaches, this solution is enhanced with a low-cost system and non-critical performance constraints, and it is suitable for extensive deployment in PV power plants. Moreover, it is easily implemented in existing PV installations, since no additional wiring is required. The system has been implemented and assessed in a Spanish PV power plant connected to the grid. Results and estimations of PV module performances are also included in the paper.

Climate, air quality and human health benefits of various solar photovoltaic deployment scenarios in China in 2030

NASA Astrophysics Data System (ADS)

Yang, Junnan; Li, Xiaoyuan; Peng, Wei; Wagner, Fabian; Mauzerall, Denise L.

2018-06-01

Solar photovoltaic (PV) electricity generation can greatly reduce both air pollutant and greenhouse gas emissions compared to fossil fuel electricity generation. The Chinese government plans to greatly scale up solar PV installation between now and 2030. However, different PV development pathways will influence the range of air quality and climate benefits. Benefits depend on how much electricity generated from PV is integrated into power grids and the type of power plant displaced. Using a coal-intensive power sector projection as the base case, we estimate the climate, air quality, and related human health benefits of various 2030 PV deployment scenarios. We use the 2030 government goal of 400 GW installed capacity but vary the location of PV installation and the extent of inter-provincial PV electricity transmission. We find that deploying distributed PV in the east with inter-provincial transmission maximizes potential CO2 reductions and air quality-related health benefits (4.2% and 1.2% decrease in national total CO2 emissions and air pollution-related premature deaths compared to the base case, respectively). Deployment in the east with inter-provincial transmission results in the largest benefits because it maximizes displacement of the dirtiest coal-fired power plants and minimizes PV curtailment, which is more likely to occur without inter-provincial transmission. We further find that the maximum co-benefits achieved with deploying PV in the east and enabling inter-provincial transmission are robust under various maximum PV penetration levels in both provincial and regional grids. We find large potential benefits of policies that encourage distributed PV deployment and facilitate inter-provincial PV electricity transmission in China.

Lacunar Infarcts, but Not Perivascular Spaces, Are Predictors of Cognitive Decline in Cerebral Small-Vessel Disease

PubMed Central

Trippier, Sarah; Lawrence, Andrew J.; Lambert, Christian; Zeestraten, Eva; Williams, Owen A.; Patel, Bhavini; Morris, Robin G.; Barrick, Thomas R.; MacKinnon, Andrew D.; Markus, Hugh S.

2018-01-01

Background and Purpose— Cerebral small-vessel disease is a major cause of cognitive impairment. Perivascular spaces (PvS) occur in small-vessel disease, but their relationship to cognitive impairment remains uncertain. One reason may be difficulty in distinguishing between lacunes and PvS. We determined the relationship between baseline PvS score and PvS volume with change in cognition over a 5-year follow-up. We compared this to the relationship between baseline lacune count and total lacune volume with cognition. In addition, we examined change in PvS volume over time. Methods— Data from the prospective SCANS study (St Georges Cognition and Neuroimaging in Stroke) of patients with symptomatic lacunar stroke and confluent leukoaraiosis were used (n=121). Multimodal magnetic resonance imaging was performed annually for 3 years and neuropsychological testing annually for 5 years. Lacunes were manually identified and distinguished from PvS. PvS were rated using a validated visual rating scale, and PvS volumes calculated using T1-weighted images. Linear mixed-effect models were used to determine the impact of PvS and lacunes on cognition. Results— Baseline PvS scores or volumes showed no association with cognitive indices. No change was detectable in PvS volumes over the 3 years. In contrast, baseline lacunes associated with all cognitive indices and predicted cognitive decline over the 5-year follow-up. Conclusions— Although a feature of small-vessel disease, PvS are not a predictor of cognitive decline, in contrast to lacunes. This study highlights the importance of carefully differentiating between lacunes and PvS in studies investigating vascular cognitive impairment. PMID:29438074

Contribution of Innate Cortical Mechanisms to the Maturation of Orientation Selectivity in Parvalbumin Interneurons

PubMed Central

Figueroa Velez, Dario X.; Ellefsen, Kyle L.; Hathaway, Ethan R.; Carathedathu, Mathew C.

2017-01-01

The maturation of cortical parvalbumin-positive (PV) interneurons depends on the interaction of innate and experience-dependent factors. Dark-rearing experiments suggest that visual experience determines when broad orientation selectivity emerges in visual cortical PV interneurons. Here, using neural transplantation and in vivo calcium imaging of mouse visual cortex, we investigated whether innate mechanisms contribute to the maturation of orientation selectivity in PV interneurons. First, we confirmed earlier findings showing that broad orientation selectivity emerges in PV interneurons by 2 weeks after vision onset, ∼35 d after these cells are born. Next, we assessed the functional development of transplanted PV (tPV) interneurons. Surprisingly, 25 d after transplantation (DAT) and >2 weeks after vision onset, we found that tPV interneurons have not developed broad orientation selectivity. By 35 DAT, however, broad orientation selectivity emerges in tPV interneurons. Transplantation does not alter orientation selectivity in host interneurons, suggesting that the maturation of tPV interneurons occurs independently from their endogenous counterparts. Together, these results challenge the notion that the onset of vision solely determines when PV interneurons become broadly tuned. Our results reveal that an innate cortical mechanism contributes to the emergence of broad orientation selectivity in PV interneurons. SIGNIFICANCE STATEMENT Early visual experience and innate developmental programs interact to shape cortical circuits. Visual-deprivation experiments have suggested that the onset of visual experience determines when interneurons mature in the visual cortex. Here we used neuronal transplantation and cellular imaging of visual responses to investigate the maturation of parvalbumin-positive (PV) interneurons. Our results suggest that the emergence of broad orientation selectivity in PV interneurons is innately timed. PMID:28123018

Feline morbillivirus, a previously undescribed paramyxovirus associated with tubulointerstitial nephritis in domestic cats

PubMed Central

Woo, Patrick C. Y.; Lau, Susanna K. P.; Wong, Beatrice H. L.; Fan, Rachel Y. Y.; Wong, Annette Y. P.; Zhang, Anna J. X.; Wu, Ying; Choi, Garnet K. Y.; Li, Kenneth S. M.; Hui, Janet; Wang, Ming; Zheng, Bo-Jian; Chan, K. H.; Yuen, Kwok-Yung

2012-01-01

We describe the discovery and isolation of a paramyxovirus, feline morbillivirus (FmoPV), from domestic cat (Felis catus). FmoPV RNA was detected in 56 (12.3%) of 457 stray cats (53 urine, four rectal swabs, and one blood sample) by RT-PCR. Complete genome sequencing of three FmoPV strains showed genome sizes of 16,050 bases, the largest among morbilliviruses, because of unusually long 5′ trailer sequences of 400 nt. FmoPV possesses identical gene contents (3′-N-P/V/C-M-F-H-L-5′) and is phylogenetically clustered with other morbilliviruses. IgG against FmoPV N protein was positive in 49 sera (76.7%) of 56 RT-PCR–positive cats, but 78 (19.4%) of 401 RT-PCR–negative cats (P < 0.0001) by Western blot. FmoPV was isolated from CRFK feline kidney cells, causing cytopathic effects with cell rounding, detachment, lysis, and syncytia formation. FmoPV could also replicate in subsequent passages in primate Vero E6 cells. Infected cell lines exhibited finely granular and diffuse cytoplasmic fluorescence on immunostaining for FmoPV N protein. Electron microscopy showed enveloped virus with typical “herringbone” appearance of helical N in paramyxoviruses. Histological examination of necropsy tissues in two FmoPV-positive cats revealed interstitial inflammatory infiltrate and tubular degeneration/necrosis in kidneys, with decreased cauxin expression in degenerated tubular epithelial cells, compatible with tubulointerstitial nephritis (TIN). Immunohistochemical staining revealed FmoPV N protein-positive renal tubular cells and mononuclear cells in lymph nodes. A case-control study showed the presence of TIN in seven of 12 cats with FmoPV infection, but only two of 15 cats without FmoPV infection (P < 0.05), suggesting an association between FmoPV and TIN. PMID:22431644

Appraising into the Sun: Six-State Solar Home Paired-Sale Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lawrence Berkeley National Laboratory

Although residential solar photovoltaic (PV) installations have proliferated, PV systems on some U.S. homes still receive no value during an appraisal because comparable home sales are lacking. To value residential PV, some previous studies have employed paired-sales appraisal methods to analyze small PV home samples in depth, while others have used statistical methods to analyze large samples. Our first-of-its-kind study connects the two approaches. It uses appraisal methods to evaluate sales price premiums for owned PV systems on single-unit detached houses that were also evaluated in a large statistical study. Independent appraisers evaluated 43 recent home sales pairs in sixmore » states: California, Oregon, Florida, Maryland, North Carolina, and Pennsylvania. We compare these results with contributory-value estimates—based on income (using the PV Value® tool), gross cost, and net cost—as well as hedonic modeling results from the recent statistical study. The results provide strong, appraisal-based evidence of PV premiums in all states. More importantly, the results support the use of cost- and incomebased PV premium estimates when paired-sales analysis is impossible. PV premiums from the paired-sales analysis are most similar to net PV cost estimates. PV Value® income results generally track the appraised premiums, although conservatively. The appraised premiums are in agreement with the hedonic modeling results as well, which bolsters the suitability of both approaches for estimating PV home premiums. Therefore, these results will benefit valuation professionals and mortgage lenders who increasingly are encountering homes equipped with PV and need to understand the factors that can both contribute to and detract from market value.« less

Quantitative analysis of poliomyelitis-like paralysis in mice induced by a poliovirus replicon.

PubMed

Arita, Minetaro; Nagata, Noriyo; Sata, Tetsutaro; Miyamura, Tatsuo; Shimizu, Hiroyuki

2006-11-01

Poliovirus (PV) infection causes severe paralysis, typically of the legs, by destruction of the motor neurons in the spinal cord. In this study, the relationship between PV replication in the spinal cord, damage in the motor neurons and poliomyelitis-like paralysis was analysed in transgenic mice expressing the human PV receptor (TgPVR21). First, a PV replicon encoding firefly luciferase in place of the capsid genes (PV-Fluc mc) was trans-encapsidated in 293T cells and the trans-encapsidated PV-Fluc mc (TE-PV-Fluc mc) was then inoculated into the spinal cords of TgPVR21 mice. TE-PV-Fluc mc was recovered with a titre of 6.3 x 10(7) infectious units ml(-1), which was comparable to those of PV1 strains. TgPVR21 mice inoculated with TE-PV-Fluc mc showed non-lethal paralysis of the hindlimbs, with severity ranging from a decline in grip strength to complete flaccid paralysis. The replication of TE-PV-Fluc mc in the spinal cord reached peak levels at 10 h post-inoculation (p.i.), followed by the appearance of paralysis at as early as 12 h p.i., reaching a plateau at 16 h p.i. Histological analysis showed a correlation between the lesion and the severity of the clinical symptoms in most mice. However, severe paralysis could also be observed with an apparently low lesion score, where as few as 5.3 x 10(2) motor neurons (1.4 % of the susceptible cells in the lumbar cord) were infected by TE-PV-Fluc mc. These results indicate that PV replication in a small population of the motor neurons was critical for severe residual poliomyelitis-like paralysis in TgPVR21 mice.

PV_LIB Toolbox v. 1.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

2015-12-09

PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system's plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

Fault detection and diagnosis of photovoltaic systems

NASA Astrophysics Data System (ADS)

Wu, Xing

The rapid growth of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. One of the primary aims of research in building-integrated PV systems is to improve the performance of the system's efficiency, availability, and reliability. Although much work has been done on technological design to increase a photovoltaic module's efficiency, there is little research so far on fault diagnosis for PV systems. Faults in a PV system, if not detected, may not only reduce power generation, but also threaten the availability and reliability, effectively the "security" of the whole system. In this paper, first a circuit-based simulation baseline model of a PV system with maximum power point tracking (MPPT) is developed using MATLAB software. MATLAB is one of the most popular tools for integrating computation, visualization and programming in an easy-to-use modeling environment. Second, data collection of a PV system at variable surface temperatures and insolation levels under normal operation is acquired. The developed simulation model of PV system is then calibrated and improved by comparing modeled I-V and P-V characteristics with measured I--V and P--V characteristics to make sure the simulated curves are close to those measured values from the experiments. Finally, based on the circuit-based simulation model, a PV model of various types of faults will be developed by changing conditions or inputs in the MATLAB model, and the I--V and P--V characteristic curves, and the time-dependent voltage and current characteristics of the fault modalities will be characterized for each type of fault. These will be developed as benchmark I-V or P-V, or prototype transient curves. If a fault occurs in a PV system, polling and comparing actual measured I--V and P--V characteristic curves with both normal operational curves and these baseline fault curves will aid in fault diagnosis.

[Varicocele and coincidental abacterial prostato-vesiculitis: negative role about the sperm output].

PubMed

Vicari, Enzo; La Vignera, Sandro; Tracia, Angelo; Cardì, Francesco; Donati, Angelo

2003-03-01

To evaluate the frequency and the role of a coincidentally expressed abacterial prostato-vesiculitis (PV) on sperm output in patients with left varicocele (Vr). We evaluated 143 selected infertile patients (mean age 27 years, range 21-43), with oligo- and/or astheno- and/or teratozoospermia (OAT) subdivided in two groups. Group A included 76 patients with previous varicocelectomy and persistent OAT. Group B included 67 infertile patients (mean age 26 years, range 21-37) with OAT and not varicocelectomized. Patients with Vr and coincidental didymo-epididymal ultrasound (US) abnormalities were excluded from the study. Following rectal prostato-vesicular ultrasonography, each group was subdivided in two subsets on the basis of the absence (group A: subset Vr-/PV-; and group B: subset Vr+/PV-) or the presence of an abacterial PV (group A: subset Vr-/PV+; group B: subset Vr+/PV+). Particularly, PV was present in 47.4% and 41.8% patients of groups A and B, respectively. This coincidental pathology was ipsilateral with Vr in the 61% of the cases. Semen analysis was performed in all patients. Patients of group A showed a total sperm number significantly higher than those found in group B. In presence of PV, sperm parameters were not significantly different between matched--subsets (Vr-/PV+ vs. Vr+/PV+). In absence of PV, the sperm density, the total sperm number and the percentage of forward motility from subset with previous varicocelectomy (Vr-/PV) exhibited values significantly higher than those found in the matched--subset (Vr+/PV-). Sperm analysis alone performed in patients with left Vr is not a useful prognostic post-varicocelectomy marker. Since following varicocelectomy a lack of sperm response could mask another coincidental pathology, the identification through US scans of a possible PV may be mandatory. On the other hand, an integrated uro-andrological approach, including US scans, allows to enucleate subsets of patients with Vr alone, who will have an expected better sperm response following Vr repair.

Photovoltaics: Energy for the New Millenium

NASA Astrophysics Data System (ADS)

Surek, Thomas

2000-04-01

Photovoltaics (PV) is a semiconductor-based technology that directly converts sunlight to electricity. The stimulus for terrestrial PV started more than 25 years ago in response to the oil crises of the 1970s, which resulted in major government programs in the United States, Europe, Japan, and elsewhere. Ongoing concerns with the global environment, as well as the worldwide efforts to seek alternate, indigenous sources of energy, continue to drive the investment in PV research and deployment. Today, the manufacture, sale, and use of PV has become a billion-dollar industry worldwide, with nearly 200 megawatts (MW) of PV modules shipped in 1999. The twenty five years of research and development led to the discovery of new PV materials, devices, and fabrication approaches; continuing improvements in the efficiency and reliability of solar cells and modules; and lower PV module and system costs. This talk reviews the rapid progress that has occurred in PV technology from the laboratory to the marketplace, including reviews of the leading technology options, status and issues, and key industry players. New processes for fabricating PV materials and devices, and innovative PV approaches with low-cost potential are elements of an ongoing research program aimed at future advancements in PV cost and performance While major market opportunities continue to exist in the developing countries, where sizable populations are without any electricity, today's manufacturing expansions are fueled by market initiatives for grid-connected PV in residential and commercial buildings. The combinations of increased production capacities, with the attendant cost reductions as a result of economies of scale, are expected to lead to sustainable markets. A key to achieving the ultimate potential of PV is to continue to increase the sunlight-to-electricity conversion efficiencies and translate the laboratory successes to cost-competitive products. Building a robust technology base is essential to overcoming this high-risk transition. Then PV will make a globally significant contribution to our energy supply and environment.

Internal resilience, peer victimization, and suicidal ideation among adolescents.

PubMed

Hirschtritt, Matthew E; Ordóñez, Anna E; Rico, Yvette C; LeWinn, Kaja Z

2015-11-01

Our goal was to examine the association between peer victimization (PV) and suicidal ideation (SI), and the degree to which internal resilience moderates this association. We examined the independent associations between PV frequency and type (verbal, cyber, physical, and relational), internal resilience, and the risk of SI within the last 12 months among 9th and 11th grade students participating in the California Healthy Kids Survey (CHKS) (n=42,594; 55.2% female; 72.2% non-white). Odds ratios (OR) of SI associated with very low- (at least 1 PV type 1 time, but none more than 1 time), low- (at least 1 PV type 2-3 times, but none more than 2-3 times), and moderate/high- (at least 1 PV type 4 times or more) frequency PV compared with no PV were 1.30 (95% CI=1.15-1.45), 1.70 (95% CI=1.51-1.90) and 2.47 (95% CI=1.23-2.73), respectively. Any exposure to physical (OR=1.31; 95% CI=1.19-1.44), relational (OR=1.26; 95% CI=1.15-1.38), verbal (OR=1.38; 95% CI=1.27-1.50), or cyber (OR=1.26; 95% CI=1.15-1.39) PV was associated with increased odds of SI compared with no PV. Internal resilience was associated with lower odds of SI (OR=0.98, 95% CI=0.98-0.99), regardless of PV exposure. The slope between internal resilience and SI was significantly steeper for those subjects who experienced verbal PV (OR interaction=0.99; 95% CI=0.98-1.00). Even infrequent PV was found to be associated with increased risk for SI. Internal resilience was associated with reduced SI, particularly for verbal forms of PV. Our results suggested that efforts to decrease SI among adolescents should be directed toward both preventing PV and strengthening internal resilience.

On-line monitoring system of PV array based on internet of things technology

NASA Astrophysics Data System (ADS)

Li, Y. F.; Lin, P. J.; Zhou, H. F.; Chen, Z. C.; Wu, L. J.; Cheng, S. Y.; Su, F. P.

2017-11-01

The Internet of Things (IoT) Technology is used to inspect photovoltaic (PV) array which can greatly improve the monitoring, performance and maintenance of the PV array. In order to efficiently realize the remote monitoring of PV operating environment, an on-line monitoring system of PV array based on IoT is designed in this paper. The system includes data acquisition, data gateway and PV monitoring centre (PVMC) website. Firstly, the DSP-TMS320F28335 is applied to collect indicators of PV array using sensors, then the data are transmitted to data gateway through ZigBee network. Secondly, the data gateway receives the data from data acquisition part, obtains geographic information via GPS module, and captures the scenes around PV array via USB camera, then uploads them to PVMC website. Finally, the PVMC website based on Laravel framework receives all data from data gateway and displays them with abundant charts. Moreover, a fault diagnosis approach for PV array based on Extreme Learning Machine (ELM) is applied in PVMC. Once fault occurs, a user alert can be sent via E-mail. The designed system enables users to browse the operating conditions of PV array on PVMC website, including electrical, environmental parameters and video. Experimental results show that the presented monitoring system can efficiently real-time monitor the PV array, and the fault diagnosis approach reaches a high accuracy of 97.5%.

A study on assimilating potential vorticity data

NASA Astrophysics Data System (ADS)

Li, Yong; Ménard, Richard; Riishøjgaard, Lars Peter; Cohn, Stephen E.; Rood, Richard B.

1998-08-01

The correlation that exists between the potential vorticity (PV) field and the distribution of chemical tracers such as ozone suggests the possibility of using tracer observations as proxy PV data in atmospheric data assimilation systems. Especially in the stratosphere, there are plentiful tracer observations but a general lack of reliable wind observations, and the correlation is most pronounced. The issue investigated in this study is how model dynamics would respond to the assimilation of PV data. First, numerical experiments of identical-twin type were conducted with a simple univariate nuding algorithm and a global shallow water model based on PV and divergence (PV-D model). All model fields are successfully reconstructed through the insertion of complete PV data alone if an appropriate value for the nudging coefficient is used. A simple linear analysis suggests that slow modes are recovered rapidly, at a rate nearly independent of spatial scale. In a more realistic experiment, appropriately scaled total ozone data from the NIMBUS-7 TOMS instrument were assimilated as proxy PV data into the PV-D model over a 10-day period. The resulting model PV field matches the observed total ozone field relatively well on large spatial scales, and the PV, geopotential and divergence fields are dynamically consistent. These results indicate the potential usefulness that tracer observations, as proxy PV data, may offer in a data assimilation system.

Detection of poliovirus infection in children with acute gastroenteritis in Chiang Mai, Thailand.

PubMed

Kumthip, Kattareeya; Khamrin, Pattara; Maneekarn, Niwat

2017-05-01

Poliovirus (PV) is typically transmitted by the fecal-oral route, which means that the risk of infection and virus distribution could be achieved by exposure to the virus contaminated in food and water. The aim of this study was to determine the occurrence of PV strains by detecting the virus in pediatric patients who admitted to the hospitals with diarrhea in Chiang Mai, Thailand during 2010-2015. By applying a reverse transcription-polymerase chain reaction and nucleotide sequencing analysis of 1,300 stool specimens collected from pediatric patients, PVs were detected at 0.61% (8 out of 1,300 specimens). Among eight PV positive samples, mixed infection with norovirus or human bocavirus was detected in one each out of eight cases. All PV strains detected in this study were characterized further by phylogenetic analysis of 343 bp of the 5' UTR and 315 bp of the partial VP1 sequences. The results revealed that eight PV strains detected in the present study two of each were PV1 and PV2, and four were PV3 serotypes of the Sabin vaccine strains. The data demonstrated the presence of PV1, PV2, and PV3 Sabin vaccine strains in children with acute gastroenteritis in Chiang Mai, Thailand. J. Med. Virol. 89:775-781, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Optimal design and operation of a photovoltaic-electrolyser system using particle swarm optimisation

NASA Astrophysics Data System (ADS)

Sayedin, Farid; Maroufmashat, Azadeh; Roshandel, Ramin; Khavas, Sourena Sattari

2016-07-01

In this study, hydrogen generation is maximised by optimising the size and the operating conditions of an electrolyser (EL) directly connected to a photovoltaic (PV) module at different irradiance. Due to the variations of maximum power points of the PV module during a year and the complexity of the system, a nonlinear approach is considered. A mathematical model has been developed to determine the performance of the PV/EL system. The optimisation methodology presented here is based on the particle swarm optimisation algorithm. By this method, for the given number of PV modules, the optimal sizeand operating condition of a PV/EL system areachieved. The approach can be applied for different sizes of PV systems, various ambient temperatures and different locations with various climaticconditions. The results show that for the given location and the PV system, the energy transfer efficiency of PV/EL system can reach up to 97.83%.

Conversion of Fibroblasts to Parvalbumin Neurons by One Transcription Factor, Ascl1, and the Chemical Compound Forskolin.

PubMed

Shi, Zixiao; Zhang, Juan; Chen, Shuangquan; Li, Yanxin; Lei, Xuepei; Qiao, Huimin; Zhu, Qianwen; Hu, Baoyang; Zhou, Qi; Jiao, Jianwei

2016-06-24

Abnormalities in parvalbumin (PV)-expressing interneurons cause neurodevelopmental disorders such as epilepsy, autism, and schizophrenia. Unlike other types of neurons that can be efficiently differentiated from pluripotent stem cells, PV neurons were minimally generated using a conventional differentiation strategy. In this study we developed an adenovirus-based transdifferentiation strategy that incorporates an additional chemical compound for the efficient generation of induced PV (iPV) neurons. The chemical compound forskolin combined with Ascl1 induced ∼80% of mouse fibroblasts to iPV neurons. The iPV neurons generated by this procedure matured 5-7 days post infection and were characterized by electrophysiological properties and known neuronal markers, such as PV and GABA. Our studies, therefore, identified an efficient approach for generating PV neurons. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Simulation of Distributed PV Power Output in Oahu Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lave, Matthew Samuel

2016-08-01

Distributed solar photovoltaic (PV) power generation in Oahu has grown rapidly since 2008. For applications such as determining the value of energy storage, it is important to have PV power output timeseries. Since these timeseries of not typically measured, here we produce simulated distributed PV power output for Oahu. Simulated power output is based on (a) satellite-derived solar irradiance, (b) PV permit data by neighborhood, and (c) population data by census block. Permit and population data was used to model locations of distributed PV, and irradiance data was then used to simulate power output. PV power output simulations are presentedmore » by sub-neighborhood polygons, neighborhoods, and for the whole island of Oahu. Summary plots of annual PV energy and a sample week timeseries of power output are shown, and a the files containing the entire timeseries are described.« less

Adolescent Peer Victimization and Physical Health Problems

PubMed Central

La Greca, Annette M.; Chan, Sherilynn F.

2016-01-01

Objective Peer victimization (PV) is a key interpersonal stressor that can be traumatizing for youth. This study evaluated the relationships between overt, relational, reputational, and cyber PV and adolescents’ somatic complaints and sleep problems. Symptoms of depression and social anxiety were examined as potential mediators. Method Adolescents (N = 1,162; M age = 15.80 years; 57% female; 80% Hispanic) were assessed at three time points, 6 weeks apart, using standardized measures of PV, depression, social anxiety, sleep problems, and somatic complaints. Structural equation modeling evaluated key study aims. Results Relational, reputational, and cyber PV, but not overt PV, were directly or indirectly associated with subsequent somatic complaints and/or sleep problems. Depression and social anxiety mediated relationships between relational PV and health outcomes, whereas reputational PV was indirectly associated with somatic complaints via depression only. Discussion The stress of PV may contribute to adolescents’ sleep problems and somatic complaints and has implications for pediatric psychologists. PMID:26050245

I-V Curves from Photovoltaic Modules Deployed in Tucson

NASA Astrophysics Data System (ADS)

Kopp, Emily; Brooks, Adria; Lonij, Vincent; Cronin, Alex

2011-10-01

More than 30 Mega Watts of photo-voltaic (PV) modules are connected to the electric power grid in Tucson, AZ. However, predictions of PV system electrical yields are uncertain, in part because PV modules degrade at various rates (observed typically in the range 0% to 3 %/yr). We present I-V curves (PV output current as a function of PV output voltage) as a means to study PV module efficiency, de-ratings, and degradation. A student-made I-V curve tracer for 100-Watt modules will be described. We present I-V curves for several different PV technologies operated at an outdoor test yard, and we compare new modules to modules that have been operated in the field for 10 years.

Apparatuses to support photovoltaic modules

DOEpatents

Ciasulli, John; Jones, Jason

2017-08-22

Methods and apparatuses to support photovoltaic ("PV") modules are described. A saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. A grounding washer has a first portion to couple to a support; and a second portion coupled to the first portion to provide a ground path to a PV module. A PV system has a saddle bracket; a PV module over the saddle bracket; and a grounding washer coupled to the saddle bracket and the PV module. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets.

Photovoltaic System Pricing Trends: Historical, Recent, and Near-Term Projections 2015 Edition

DOE Data Explorer

Feldman, David; Barbose, Galen; Margolis, Robert; Bolinger, Mark; Chung, Donald; Fu, Ran; Seel, Joachim; Davidson, Carolyn; Wiser, Ryan

2016-05-13

This is the fourth edition in an annual briefing prepared jointly by LBNL and NREL intended to provide a high-level overview of historical, recent, and projected near-term PV system pricing trends in the United States. The briefing draws on several ongoing research activities at the two labs, including LBNL's annual Tracking the Sun report series, NREL's bottom-up PV cost modeling, and NREL's synthesis of PV market data and projections. The briefing examines progress in PV price reductions to help DOE and other PV stakeholders manage the transition to a market-driven PV industry, and integrates different perspectives and methodologies for characterizing PV system pricing, in order to provide a broader perspective on underlying trends within the industry.

The Value of Transparency in Distributed Solar PV Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J.; Margolis, Robert M.

Distributed solar photovoltaic (PV) markets are relatively non-transparent: PV price and product information is not readily available, searching for this information is costly (in terms of time and effort), and customers are mostly unfamiliar with the new technology. Quote aggregation, where third-party companies collect PV quotes on behalf of customers, may be one way to increase PV market transparency. In this paper, quote aggregation data are analyzed to study the value of transparency for distributed solar PV markets. The results suggest that easier access to more quotes results in lower prices. We find that installers tend to offer lower pricesmore » in more competitive market environments. We supplement the empirical analysis with key findings from interviews of residential PV installers.« less

Market assessment of photovoltaic power systems for agricultural applications in Mexico

NASA Technical Reports Server (NTRS)

Steigelmann, W.; Asmon, I.

1981-01-01

The first year of cost-competitiveness, the market potential, and the environment in which PV systems would be marketed and employed were examined. Market elements specific to Mexico addressed include: (1) useful applications and estimates of the potential market for PV systems; (2) power requirements and load profiles for applications compatible with PV usage; (3) operating and cost characteristics of power systems that compete against PV; (4) national development goals in rural electrification and rural services, technology programs and government policies that influence the demand for PV in Mexico; (5) financing mechanisms and capital available for PV acquisition; (6) channels for distribution, installation and maintenance of PV systems; and (7) appropriate methods for conducting business in Mexico.

Using the Spatial Distribution of Installers to Define Solar Photovoltaic Markets

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naim

2016-09-01

Solar PV market research to date has largely relied on arbitrary jurisdictional boundaries, such as counties, to study solar PV market dynamics. This paper seeks to improve solar PV market research by developing a methodology to define solar PV markets. The methodology is based on the spatial distribution of solar PV installers. An algorithm is developed and applied to a rich dataset of solar PV installations to study the outcomes of the installer-based market definitions. The installer-based approach exhibits several desirable properties. Specifically, the higher market granularity of the installer-based approach will allow future PV market research to study themore » relationship between market dynamics and pricing with more precision.« less

Market assessment of photovoltaic power systems for agricultural applications in Mexico

NASA Astrophysics Data System (ADS)

Steigelmann, W.; Asmon, I.

1981-07-01

The first year of cost-competitiveness, the market potential, and the environment in which PV systems would be marketed and employed were examined. Market elements specific to Mexico addressed include: (1) useful applications and estimates of the potential market for PV systems; (2) power requirements and load profiles for applications compatible with PV usage; (3) operating and cost characteristics of power systems that compete against PV; (4) national development goals in rural electrification and rural services, technology programs and government policies that influence the demand for PV in Mexico; (5) financing mechanisms and capital available for PV acquisition; (6) channels for distribution, installation and maintenance of PV systems; and (7) appropriate methods for conducting business in Mexico.

Energy Storage Requirements for Achieving 50% Penetration of Solar Photovoltaic Energy in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; Margolis, Robert

2016-09-01

We estimate the storage required to enable PV penetration up to 50% in California (with renewable penetration over 66%), and we quantify the complex relationships among storage, PV penetration, grid flexibility, and PV costs due to increased curtailment. We find that the storage needed depends strongly on the amount of other flexibility resources deployed. With very low-cost PV (three cents per kilowatt-hour) and a highly flexible electric power system, about 19 gigawatts of energy storage could enable 50% PV penetration with a marginal net PV levelized cost of energy (LCOE) comparable to the variable costs of future combined-cycle gas generatorsmore » under carbon constraints. This system requires extensive use of flexible generation, transmission, demand response, and electrifying one quarter of the vehicle fleet in California with largely optimized charging. A less flexible system, or more expensive PV would require significantly greater amounts of storage. The amount of storage needed to support very large amounts of PV might fit within a least-cost framework driven by declining storage costs and reduced storage-duration needs due to high PV penetration.« less

Energy Storage Requirements for Achieving 50% Solar Photovoltaic Energy Penetration in California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul; Margolis, Robert

2016-08-01

We estimate the storage required to enable PV penetration up to 50% in California (with renewable penetration over 66%), and we quantify the complex relationships among storage, PV penetration, grid flexibility, and PV costs due to increased curtailment. We find that the storage needed depends strongly on the amount of other flexibility resources deployed. With very low-cost PV (three cents per kilowatt-hour) and a highly flexible electric power system, about 19 gigawatts of energy storage could enable 50% PV penetration with a marginal net PV levelized cost of energy (LCOE) comparable to the variable costs of future combined-cycle gas generatorsmore » under carbon constraints. This system requires extensive use of flexible generation, transmission, demand response, and electrifying one quarter of the vehicle fleet in California with largely optimized charging. A less flexible system, or more expensive PV would require significantly greater amounts of storage. The amount of storage needed to support very large amounts of PV might fit within a least-cost framework driven by declining storage costs and reduced storage-duration needs due to high PV penetration.« less

Performance Analysis and Discussion on the Thermoelectric Element Footprint for PV-TE Maximum Power Generation

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Zhao, Xudong; Jin, Yi; Chen, Xiao; Ji, Jie; Shittu, Samson

2018-06-01

Geometrical optimisation is a valuable way to improve the efficiency of a thermoelectric element (TE). In a hybrid photovoltaic-thermoelectric (PV-TE) system, the photovoltaic (PV) and thermoelectric (TE) components have a relatively complex relationship; their individual effects mean that geometrical optimisation of the TE element alone may not be sufficient to optimize the entire PV-TE hybrid system. In this paper, we introduce a parametric optimisation of the geometry of the thermoelectric element footprint for a PV-TE system. A uni-couple TE model was built for the PV-TE using the finite element method and temperature-dependent thermoelectric material properties. Two types of PV cells were investigated in this paper and the performance of PV-TE with different lengths of TE elements and different footprint areas was analysed. The outcome showed that no matter the TE element's length and the footprint areas, the maximum power output occurs when A n /A p = 1. This finding is useful, as it provides a reference whenever PV-TE optimisation is investigated.

Felis catus papillomavirus types 1 and 4 are rarely present in neoplastic and inflammatory oral lesions of cats.

PubMed

Munday, John S; French, Adrienne F

2015-06-01

Oral squamous cell carcinomas (OSCCs) are common feline cancers. Why OSCCs are so common in cats is unknown; however, 25% of human OSCCs are caused by papillomaviruses (PVs). Two feline oral PVs (FcaPV-1 and 4) are recognized. As PVs are highly host and location specific, if PVs do cause feline OSCCs, FcaPV-1 and 4 are the most likely etiological agents. PCR primers specific for FcaPV-1 amplified DNA from 1 of 36 feline OSCCs and 1 of 16 inflammatory oral lesions. No DNA was amplified by primers specific for FcaPV-4. PV DNA was not amplified from any additional sample using consensus primers. No PV cytopathology was visible in the OSCC that contained FcaPV-1 DNA, but viral cytopathology was present in a focus of epithelial hyperplasia in the non-neoplastic sample. This study does not support a PV etiology of feline OSCCs, but shows that FcaPV-1 can asymptomatically infect the mouth of cats. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effective information channels for reducing costs of environmentally- friendly technologies: evidence from residential PV markets

NASA Astrophysics Data System (ADS)

Rai, Varun; Robinson, Scott A.

2013-03-01

Realizing the environmental benefits of solar photovoltaics (PV) will require reducing costs associated with perception, informational gaps and technological uncertainties. To identify opportunities to decrease costs associated with residential PV adoption, in this letter we use multivariate regression models to analyze a unique, household-level dataset of PV adopters in Texas (USA) to systematically quantify the effect of different information channels on aspiring PV adopters’ decision-making. We find that the length of the decision period depends on the business model, such as whether the system was bought or leased, and on special opportunities to learn, such as the influence of other PV owners in the neighborhood. This influence accrues passively through merely witnessing PV systems in the neighborhood, increasing confidence and motivation, as well as actively through peer-to-peer communications. Using these insights we propose a new framework to provide public information on PV that could drastically reduce barriers to PV adoption, thereby accelerating its market penetration and environmental benefits. This framework could also serve as a model for other distributed generation technologies.

Energy Security: From Deal Killers to Game Changers

NASA Astrophysics Data System (ADS)

Cooke, Charlie

2010-03-01

Five energy security ``deal killers" are identified: 1) Global warming and CO2 emissions from fossil fuel combustion; 2) Intermittent energy sources (wind, solar) and the presence and stability of the grid; 3) Penetration of plant defenses to produce transportation fuels from biomass; 4) Mimicking nature: artificial photosynthesis for solar energy to fuels; and 5) Spent fuel from nuclear power reactors. Transformational basic research is required to successfully change the ground rules, to transform these ``deal killers" into ``game changers." T hey are: 1) Offsetting carbon capture and storage costs through enhanced oil recovery and methane generation from high temperature geothermal saline aquifers; 2) Electrical energy storage, through batteries and super-capacitors; 3) Genetic modification of plant cell walls, and catalytic methods for transforming plant sugars into fuels; 4) Separation of solar-induced electrons from holes, and catalysis to produce fuels; and 5) Closing the nuclear fuel cycle. Basic research can revolutionize our approach to carbon-free energy by enhancing nature to achieve energy security.

STAT FAQs Part 2: Lifetime of PV Panels | State, Local, and Tribal

Science.gov Websites

is the productive lifetime and degradation rate of solar PV panels. Question: What is the productive life of solar PV panels, and do they produce the same amount of electricity year-over-year? Answer: The Governments | NREL STAT FAQs Part 2: Lifetime of PV Panels STAT FAQs Part 2: Lifetime of PV

Golden Rays - July 2017 | Solar Research | Solar Research | NREL

Science.gov Websites

Operator, First Solar, and NREL tested a 300-MW PV plant to demonstrate that, with proper controls, PV can technique to measure charge-carrier transport in PV materials. Solar Plus: A Holistic Approach to Distribution Solar PV By optimizing how PV interacts with other electricity loads at the household- and grid

A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

NASA Astrophysics Data System (ADS)

Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

2012-10-01

Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

Lightweight IMM PV Flexible Blanket Assembly

NASA Technical Reports Server (NTRS)

Spence, Brian

2015-01-01

Deployable Space Systems (DSS) has developed an inverted metamorphic multijunction (IMM) photovoltaic (PV) integrated modular blanket assembly (IMBA) that can be rolled or z-folded. This IMM PV IMBA technology enables a revolutionary flexible PV blanket assembly that provides high specific power, exceptional stowed packaging efficiency, and high-voltage operation capability. DSS's technology also accommodates standard third-generation triple junction (ZTJ) PV device technologies to provide significantly improved performance over the current state of the art. This SBIR project demonstrated prototype, flight-like IMM PV IMBA panel assemblies specifically developed, designed, and optimized for NASA's high-voltage solar array missions.

NREL Photovoltaic Program FY 1995 annual report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1996-06-01

This report summarizes the in-house and subcontracted R&D activities from Oct. 1994 through Sept. 1995; their objectives are to conduct basic, applied, and engineering research, manage subcontracted R&D projects, perform research complementary to subcontracted work, develop and maintain state-of-the-art measurement and device capabilities, develop PV manufacturing technology and modules, transfer results to industry, and evolve viable partnerships for PV systems and market development. The research activities are grouped into 5 sections: crystalline Si and advanced devices, thin-film PV, PV manufacturing, PV module and system performance and engineering, and PV applications and market development.

Emissions from photovoltaic life cycles.

PubMed

Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

2008-03-15

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

The geography of solar energy in the United States: Market definition, industry structure, and choice in solar PV adoption

DOE PAGES

O’Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naïm

2018-01-30

The solar photovoltaic (PV) installation industry comprises thousands of firms around the world who collectively installed nearly 200 million panels in 2015. Spatial analysis of the emerging industry has received considerable attention from the literature, especially on the demand side concerning peer effects and adopter clustering. However this research area does not include similarly sophisticated spatial analysis on the supply side of the installation industry. The lack of understanding of the spatial structure of the PV installation industry leaves PV market research to rely on jurisdictional lines, such as counties, to define geographic PV markets. We develop an approach thatmore » uses the spatial distribution of installers' activity to define geographic boundaries for PV markets. Our method is useful for PV market research and applicable in the contexts of other industries. We use our approach to demonstrate that the PV industry in the United States is spatially heterogeneous. Despite the emergence of some national-scale PV installers, installers are largely local and installer communities are unique from one region to the next. The social implications of the spatial heterogeneity of the emerging PV industry involve improving understanding of issues such as market power, industry consolidation, and how much choice potential adopters have.« less

On enhancing energy harvesting performance of the photovoltaic modules using an automatic cooling system and assessing its economic benefits of mitigating greenhouse effects on the environment

NASA Astrophysics Data System (ADS)

Wang, Jen-Cheng; Liao, Min-Sheng; Lee, Yeun-Chung; Liu, Cheng-Yue; Kuo, Kun-Chang; Chou, Cheng-Ying; Huang, Chen-Kang; Jiang, Joe-Air

2018-02-01

The performance of photovoltaic (PV) modules under outdoor operation is greatly affected by their location and environmental conditions. The temperature of a PV module gradually increases as it is exposed to solar irradiation, resulting in degradation of its electrical characteristics and power generation efficiency. This study adopts wireless sensor network (WSN) technology to develop an automatic water-cooling system for PV modules in order to improve their PV power generation efficiency. A temperature estimation method is developed to quickly and accurately estimate the PV module temperatures based on weather data provided from the WSN monitoring system. Further, an estimation method is also proposed for evaluation of the electrical characteristics and output power of the PV modules, which is performed remotely via a control platform. The automatic WSN-based water-cooling mechanism is designed to avoid the PV module temperature from reaching saturation. Equipping each PV module with the WSN-based cooling system, the ambient conditions are monitored automatically so that the temperature of the PV module is controlled by sprinkling water on the panel surface. The field-test experiment results show an increase in the energy harvested by the PV modules of approximately 17.75% when using the proposed WSN-based cooling system.

The geography of solar energy in the United States: Market definition, industry structure, and choice in solar PV adoption

DOE Office of Scientific and Technical Information (OSTI.GOV)

O’Shaughnessy, Eric; Nemet, Gregory F.; Darghouth, Naïm

The solar photovoltaic (PV) installation industry comprises thousands of firms around the world who collectively installed nearly 200 million panels in 2015. Spatial analysis of the emerging industry has received considerable attention from the literature, especially on the demand side concerning peer effects and adopter clustering. However this research area does not include similarly sophisticated spatial analysis on the supply side of the installation industry. The lack of understanding of the spatial structure of the PV installation industry leaves PV market research to rely on jurisdictional lines, such as counties, to define geographic PV markets. We develop an approach thatmore » uses the spatial distribution of installers' activity to define geographic boundaries for PV markets. Our method is useful for PV market research and applicable in the contexts of other industries. We use our approach to demonstrate that the PV industry in the United States is spatially heterogeneous. Despite the emergence of some national-scale PV installers, installers are largely local and installer communities are unique from one region to the next. The social implications of the spatial heterogeneity of the emerging PV industry involve improving understanding of issues such as market power, industry consolidation, and how much choice potential adopters have.« less

[Role of the National Poliovirus Laboratory for the Program of eradication and poliomyelitis surveillance].

PubMed

Trallero, Gloria; Cabrerizo, María; Avellón, Ana

2013-01-01

The Spanish acute flaccid paralysis surveillance network is coordinated by the National Poliovirus Laboratory (NPL), which, since 1998, carries out polioviruses (PV) and other enteroviruses detected characterization by cell culture and molecular techniques. A total of 110,725 (70046+40679) samples were studied between 1998-2012 and enteroviruses were detected in 8% of these. Among these enteroviruses 241 PV were characterized as PV Sabin-like, except samples belong to an imported poliomyelitis case, all of which were characterised as vaccine derived PV type 2. The NPL has carried out the serotyping and the intratypic differentiation of all the isolated PV in Spain of any syndrome. It is shown that wild PV has not circulated in our country during the 15 years studied and that has led to the signing of the Act of the "eradication of poliomyelitis in Spain" by WHO in 2001, and the /"certification of the eradication of wild PV free for European countries" on 21 June 2002. Currently only 3 countries have endemic transmission of wild PV (Pakistan, Afghanistan and Nigeria). Until a complete worldwide eradication, was achieved, Spain will actively continue to participate in the maintenance of the poliomyelitis eradication infrastructure by monitoring and vaccination as well as the wild PV containment plan to avoid the spread of wild PV.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass

NASA Astrophysics Data System (ADS)

Yilbas, Bekir Sami.; Ali, Haider; Khaled, Mazen M.; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K.

2015-10-01

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Construction of EGFP-labeling system for visualizing the infection process of Xanthomonas axonopodis pv. citri in planta.

PubMed

Liu, Li-Ping; Deng, Zi-Niu; Qu, Jin-Wang; Yan, Jia-Wen; Catara, Vittoria; Li, Da-Zhi; Long, Gui-You; Li, Na

2012-09-01

Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. To monitor the infection process of Xac in different citrus plants, the enhanced green florescent protein (EGFP) visualizing system was constructed to visualize the propagation and localization in planta. First, the wild-type Xac was isolated from the diseased leaves of susceptible 'Bingtang' sweet orange, and then the isolated Xac was labeled with EGFP by triparental mating. After PCR identification, the growth kinetics and pathogenicity of the transformants were analyzed in comparison with the wild-type Xac. The EGFP-labeled bacteria were inoculated by spraying on the surface and infiltration in the mesophyll of 'Bingtang' sweet orange leaves. The bacterial cell multiplication and diffusion processes were observed directly under confocal laser scanning microscope at different intervals after inoculation. The results indicated that the EGFP-labeled Xac releasing clear green fluorescence light under fluorescent microscope showed the infection process and had the same pathogenicity as the wild type to citrus. Consequently, the labeled Xac demonstrated the ability as an efficient tool to monitor the pathogen infection.

Discrete Painlevé equations for a class of PVI τ-functions given as U(N) averages

NASA Astrophysics Data System (ADS)

Forrester, P. J.; Witte, N. S.

2005-09-01

In a recent work, difference equations (Laguerre-Freud equations) for the bi-orthogonal polynomials and related quantities corresponding to the weight on the unit circle w(z)=\\prod^m_{j=1}(z-z_j(t))^{\\rho_j} were derived. It is shown here that in the case m = 3, these difference equations, when applied to the calculation of the underlying U(N) average, reduce to a coupled system identifiable with that obtained by Adler and van Moerbeke, using the methods of the Toeplitz lattice and Virasoro constraints. Moreover, it is shown that this coupled system can be reduced to yield the discrete fifth Painlevé equation dPV as it occurs in the theory of the sixth Painlevé system. Methods based on affine Weyl group symmetries of Bäcklund transformations have previously yielded the dPV equation, but with different parameters for the same problem. We find an explicit mapping between the two forms. Applications of our results are made to give recurrences for the gap probabilities and moments in the circular unitary ensemble of random matrices, and to the diagonal spin-spin correlation function of the square lattice Ising model.

Influence of dust and mud on the optical, chemical, and mechanical properties of a pv protective glass.

PubMed

Yilbas, Bekir Sami; Ali, Haider; Khaled, Mazen M; Al-Aqeeli, Nasser; Abu-Dheir, Numan; Varanasi, Kripa K

2015-10-30

Recent developments in climate change have increased the frequency of dust storms in the Middle East. Dust storms significantly influence the performances of solar energy harvesting systems, particularly (photovoltaic) PV systems. The characteristics of the dust and the mud formed from this dust are examined using various analytical tools, including optical, scanning electron, and atomic force microscopies, X-ray diffraction, energy spectroscopy, and Fourier transform infrared spectroscopy. The adhesion, cohesion and frictional forces present during the removal of dry mud from the glass surface are determined using a microtribometer. Alkali and alkaline earth metal compounds in the dust dissolve in water to form a chemically active solution at the glass surface. This solution modifies the texture of the glass surface, thereby increasing the microhardness and decreasing the transmittance of the incident optical radiation. The force required to remove the dry mud from the glass surface is high due to the cohesive forces that result from the dried mud solution at the interface between the mud and the glass. The ability altering the characteristics of the glass surface could address the dust/mud-related limitations of protective surfaces and has implications for efficiency enhancements in solar energy systems.

Prognostication in Philadelphia Chromosome Negative Myeloproliferative Neoplasms: a Review of the Recent Literature.

PubMed

Zhou, Amy; Afzal, Amber; Oh, Stephen T

2017-10-01

The prognosis for patients with Philadelphia chromosome (Ph)-negative myeloproliferative neoplasms (MPNs) is highly variable. All Ph-negative MPNs carry an increased risk for thrombotic complications, bleeding, and leukemic transformation. Several clinical, biological, and molecular prognostic factors have been identified in recent years, which provide important information in guiding management of patients with Ph-negative MPNs. In this review, we critically evaluate the recent published literature and discuss important new developments in clinical and molecular factors that impact survival, disease transformation, and thrombosis in patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis. Recent studies have identified several clinical factors and non-driver mutations to have prognostic impact on Ph-negative MPNs independent of conventional risk stratification and prognostic models. In polycythemia vera (PV), leukocytosis, abnormal karyotype, phlebotomy requirement on hydroxyurea, increased bone marrow fibrosis, and mutations in ASXL1, SRSF2, and IDH2 were identified as additional adverse prognostic factors. In essential thrombocythemia (ET), JAK2 V617F mutation, splenomegaly, and mutations in SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2 were found to be additional negative prognostic factors. Bone marrow fibrosis and mutations in ASXL1, SRSF2, EZH2, and IDH1/2 have been found to be additional prognostic factors in primary myelofibrosis (PMF). CALR mutations appear to be a favorable prognostic factor in PMF, which has not been clearly demonstrated in ET. The prognosis for patients with PV, ET, and PMF is dependent upon the presence or absence of several clinical, biological, and molecular risk factors. The significance of additional risk factors identified in these recent studies will need further validation in prospective studies to determine how they may be best utilized in the management of these disorders.

Concentrated solar power plants impact on PV penetration level and grid flexibility under Egyptian climate

NASA Astrophysics Data System (ADS)

Moukhtar, Ibrahim; Elbaset, Adel A.; El Dein, Adel Z.; Qudaih, Yaser; Mitani, Yasunori

2018-05-01

Photovoltaic (PV) system integration in the electric grid has been increasing over the past decades. However, the impact of PV penetration on the electric grid, especially during the periods of higher and lower generation for the solar system at the middle of the day and during cloudy weather or at night respectively, limit the high penetration of solar PV system. In this research, a Concentrated Solar Power (CSP) with Thermal Energy Storage (TES) has been aggregated with PV system in order to accommodate the required electrical power during the higher and lower solar energy at all timescales. This paper analyzes the impacts of CSP on the grid-connected PV considering high penetration of PV system, particularly when no energy storages in the form of batteries are used. Two cases have been studied, the first when only PV system is integrated into the electric grid and the second when two types of solar energy (PV and CSP) are integrated. The System Advisor Model (SAM) software is used to simulate the output power of renewable energy. Simulation results show that the performance of CSP has a great impact on the penetration level of PV system and on the flexibility of the electric grid. The overall grid flexibility increases due to the ability of CSP to store and dispatch the generated power. In addition, CSP/TES itself has inherent flexibility. Therefore, CSP reduces the minimum generation constraint of the conventional generators that allows more penetration of the PV system.

High prevalence of turkey parvovirus in turkey flocks from Hungary experiencing enteric disease syndromes.

PubMed

Palade, Elena Alina; Demeter, Zoltán; Hornyák, Akos; Nemes, Csaba; Kisary, János; Rusvai, Miklós

2011-09-01

Samples collected in 2008 and 2009, from 49 turkey flocks of 6 to 43 days in age and presenting clinical signs of enteric disease and high mortality, were tested by polymerase chain reaction and reverse transcription-polymerase chain reaction for the presence of viruses currently associated with enteric disease (ED) syndromes: astrovirus, reovirus, rotavirus, coronavirus, adenovirus, and parvovirus. Turkey astroviruses were found in 83.67% of the cases and turkey astrovirus 2 (TAst-2) in 26.53%. The investigations directly demonstrated the high prevalence of turkey parvovirus (TuPV) in 23 flocks (46.9%) experiencing signs of ED, making this pathogen the second most identified after astroviruses. Phylogenetic analysis on a 527 base pair-long region from the NS1 gene revealed two main clusters, a chicken parvovirus (ChPV) and a TuPV group, but also the presence of a divergent branch of tentatively named "TuPV-like ChPV" strains. The 23 Hungarian TuPV strains were separately positioned in two groups from the American origin sequences in the TuPV cluster. An Avail-based restriction fragment length polymorphism assay has also been developed for the quick differentiation of TuPV, ChPV, and divergent TuPV-like ChPV strains. As most detected enteric viruses have been directly demonstrated in healthy turkey flocks as well, the epidemiology of this disease complex remains unclear, suggesting that a certain combination of pathogens, environmental factors, or both are necessary for the development of clinical signs.

Interband cascade (IC) photovoltaic (PV) architecture for PV devices

DOEpatents

Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

2015-10-20

A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

Fault Analysis in Solar Photovoltaic Arrays

NASA Astrophysics Data System (ADS)

Zhao, Ye

Fault analysis in solar photovoltaic (PV) arrays is a fundamental task to increase reliability, efficiency and safety in PV systems. Conventional fault protection methods usually add fuses or circuit breakers in series with PV components. But these protection devices are only able to clear faults and isolate faulty circuits if they carry a large fault current. However, this research shows that faults in PV arrays may not be cleared by fuses under some fault scenarios, due to the current-limiting nature and non-linear output characteristics of PV arrays. First, this thesis introduces new simulation and analytic models that are suitable for fault analysis in PV arrays. Based on the simulation environment, this thesis studies a variety of typical faults in PV arrays, such as ground faults, line-line faults, and mismatch faults. The effect of a maximum power point tracker on fault current is discussed and shown to, at times, prevent the fault current protection devices to trip. A small-scale experimental PV benchmark system has been developed in Northeastern University to further validate the simulation conclusions. Additionally, this thesis examines two types of unique faults found in a PV array that have not been studied in the literature. One is a fault that occurs under low irradiance condition. The other is a fault evolution in a PV array during night-to-day transition. Our simulation and experimental results show that overcurrent protection devices are unable to clear the fault under "low irradiance" and "night-to-day transition". However, the overcurrent protection devices may work properly when the same PV fault occurs in daylight. As a result, a fault under "low irradiance" and "night-to-day transition" might be hidden in the PV array and become a potential hazard for system efficiency and reliability.

Genetic polymorphism and natural selection of Duffy binding protein of Plasmodium vivax Myanmar isolates

PubMed Central

2012-01-01

Background Plasmodium vivax Duffy binding protein (PvDBP) plays an essential role in erythrocyte invasion and a potential asexual blood stage vaccine candidate antigen against P. vivax. The polymorphic nature of PvDBP, particularly amino terminal cysteine-rich region (PvDBPII), represents a major impediment to the successful design of a protective vaccine against vivax malaria. In this study, the genetic polymorphism and natural selection at PvDBPII among Myanmar P. vivax isolates were analysed. Methods Fifty-four P. vivax infected blood samples collected from patients in Myanmar were used. The region flanking PvDBPII was amplified by PCR, cloned into Escherichia coli, and sequenced. The polymorphic characters and natural selection of the region were analysed using the DnaSP and MEGA4 programs. Results Thirty-two point mutations (28 non-synonymous and four synonymous mutations) were identified in PvDBPII among the Myanmar P. vivax isolates. Sequence analyses revealed that 12 different PvDBPII haplotypes were identified in Myanmar P. vivax isolates and that the region has evolved under positive natural selection. High selective pressure preferentially acted on regions identified as B- and T-cell epitopes of PvDBPII. Recombination may also be played a role in the resulting genetic diversity of PvDBPII. Conclusions PvDBPII of Myanmar P. vivax isolates displays a high level of genetic polymorphism and is under selective pressure. Myanmar P. vivax isolates share distinct types of PvDBPII alleles that are different from those of other geographical areas. These results will be useful for understanding the nature of the P. vivax population in Myanmar and for development of PvDBPII-based vaccine. PMID:22380592

Breaking the Intergenerational Cycle: Partner Violence, Child-Parent Attachment, and Children's Aggressive Behaviors.

PubMed

Juan, Shao-Chiu; Washington, Heather M; Kurlychek, Megan C

2017-02-01

The link between exposure to violence in the home and children's later exhibition of violent behaviors is well documented in the criminological literature. To date, most research on partner violence (PV) and children's welfare has focused on adolescent outcomes. As such, we know little about how PV affects the behavior of the youngest, and perhaps most vulnerable population of children who have been exposed to PV. Our understanding of the PV-child behavior association is also limited because extant research has focused less attention on identifying risk factors that explain and modify the link between exposure to PV and children's behavior. We use data from the Fragile Families and Child Wellbeing Study, a five-wave longitudinal study of U.S.-born children ( N = 2,896) and structural equation modeling (SEM), to explore the impact of PV exposure on later aggressive behaviors. We extend the literature on PV exposure and childhood aggression in three ways: (a) We focus on young children's behavioral outcomes; (b) we identify child-parent attachment as a potential moderator of the PV-childhood aggression relationship; and (c) we investigate variation in the effect of PV exposure on children's aggressive behavior by children's attachment to parents. Findings support our hypotheses that exposure to PV during first 3 years of life is associated with increased aggression at age 5 and age 9. We find that the effect of PV on aggression at age 9 is fully mediated through the parent-child attachment. Contrary to our expectations, we do not find evidence of a strong parent-child attachment moderating the impact of PV exposure on children's aggressive behavior.

A step towards removing plasma volume variance from the Athlete's Biological Passport: The use of biomarkers to describe vascular volumes from a simple blood test.

PubMed

Lobigs, Louisa M; Sottas, Pierre-Edouard; Bourdon, Pitre C; Nikolovski, Zoran; El-Gingo, Mohamed; Varamenti, Evdokia; Peeling, Peter; Dawson, Brian; Schumacher, Yorck O

2018-02-01

The haematological module of the Athlete's Biological Passport (ABP) has significantly impacted the prevalence of blood manipulations in elite sports. However, the ABP relies on a number of concentration-based markers of erythropoiesis, such as haemoglobin concentration ([Hb]), which are influenced by shifts in plasma volume (PV). Fluctuations in PV contribute to the majority of biological variance associated with volumetric ABP markers. Our laboratory recently identified a panel of common chemistry markers (from a simple blood test) capable of describing ca 67% of PV variance, presenting an applicable method to account for volume shifts within anti-doping practices. Here, this novel PV marker was included into the ABP adaptive model. Over a six-month period (one test per month), 33 healthy, active males provided blood samples and performed the CO-rebreathing method to record PV (control). In the final month participants performed a single maximal exercise effort to promote a PV shift (mean PV decrease -17%, 95% CI -9.75 to -18.13%). Applying the ABP adaptive model, individualized reference limits for [Hb] and the OFF-score were created, with and without the PV correction. With the PV correction, an average of 66% of [Hb] within-subject variance is explained, narrowing the predicted reference limits, and reducing the number of atypical ABP findings post-exercise. Despite an increase in sensitivity there was no observed loss of specificity with the addition of the PV correction. The novel PV marker presented here has the potential to improve the ABP's rate of correct doping detection by removing the confounding effects of PV variance. Copyright © 2017 John Wiley & Sons, Ltd.

On the relationship factor between the PV module temperature and the solar radiation on it for various BIPV configurations

NASA Astrophysics Data System (ADS)

Kaplanis, S.; Kaplani, E.

2014-10-01

Temperatures of c-Si, pc-Si and a-Si PV modules making part of a roof in a building or hanging outside windows with various inclinations were measured with respect to the Intensity of the solar radiation on them under various environmental conditions. A relationship coefficient f was provided whose values are compared to those from a PV array operating in a free standing mode on a terrace. A theoretical model to predict f was elaborated. According to the analysis, the coefficient f takes higher values for PV modules embedded on a roof compared to the free standing PV array. The wind effect is much stronger for the free standing PV than for any BIPV configuration, either the PV is part of the roof, or placed upon the roof, or is placed outside a window like a shadow hanger. The f coefficient depends on various parameters such as angle of inclination, wind speed and direction, as well as solar radiation. For very low wind speeds the effect of the angle of inclination, β, of the PV module with respect to the horizontal on PV temperature is clear. As the wind speed increases, the heat transfer from the PV module shifts from natural flow to forced flow and this effect vanishes. The coefficient f values range from almost 0.01 m2°C/W for free standing PV arrays at strong wind speeds, vW>7m/s, up to around 0.05 m2°C/W for the case of flexible PV modules which make part of the roof in a BIPV system.

Flow Cytometric Determination of Panton-Valentine Leucocidin S Component Binding

PubMed Central

Gauduchon, Valérie; Werner, Sandra; Prévost, Gilles; Monteil, Henri; Colin, Didier A.

2001-01-01

The binding of the S component (LukS-PV) from the bicomponent staphylococcal Panton-Valentine leucocidin to human polymorphonuclear neutrophils (PMNs) and monocytes was determined using flow cytometry and a single-cysteine substitution mutant of LukS-PV. The mutant was engineered by replacing a glycine at position 10 with a cysteine and was labeled with a fluorescein moiety. The biological activity of the mutant was identical to that of the native protein. It has been shown that LukS-PV has a high affinity for PMNs (Kd = 0.07 ± 0.02 nM, n = 5) and monocytes (Kd = 0.020 ± 0.003 nM, n = 3) with maximal binding capacities of 197,000 and 80,000 LukS-PV molecules per cell, respectively. The nonspecifically bound molecules of LukS-PV do not form pores in the presence of the F component (LukF-PV) of leucocidin. LukS-PV and HlgC share the same receptor on PMNs, but the S components of other staphylococcal leukotoxins, HlgA, LukE, and LukM, do not compete with LukS-PV for its receptor. Extracellular Ca2+ at physiological concentrations (1 to 2 nM) has only a slight influence on the LukS-PV binding, in contrast to its complete inhibition by Zn2+. The down-regulation by phorbol 12-myristate 13-acetate (PMA) of the binding of LukS-PV was blocked by staurosporine, suggesting that the regulatory effect of PMA depends on protein kinase C activation. The labeled mutant form of LukS-PV has proved very useful for detailed binding studies of circulating white cells by flow cytometry. LukS-PV possesses a high specific affinity for a unique receptor on PMNs and monocytes. PMID:11254598

Formation of intrathermocline eddies at ocean fronts by wind-driven destruction of potential vorticity

NASA Astrophysics Data System (ADS)

Thomas, Leif N.

2008-08-01

A mechanism for the generation of intrathermocline eddies (ITEs) at wind-forced fronts is examined using a high resolution numerical simulation. Favorable conditions for ITE formation result at fronts forced by "down-front" winds, i.e. winds blowing in the direction of the frontal jet. Down-front winds exert frictional forces that reduce the potential vorticity (PV) within the surface boundary in the frontal outcrop, providing a source for the low-PV water that is the materia prima of ITEs. Meandering of the front drives vertical motions that subduct the low-PV water into the pycnocline, pooling it into the coherent anticyclonic vortex of a submesoscale ITE. As the fluid is subducted along the outcropping frontal isopycnal, the low-PV water, which at the surface is associated with strongly baroclinic flow, re-expresses itself as water with nearly zero absolute vorticity. This generation of strong anticyclonic vorticity results from the tilting of the horizontal vorticity of the frontal jet, not from vortex squashing. During the formation of the ITE, high-PV water from the pycnocline is upwelled alongside the subducting low-PV surface water. The positive correlation between the ITE's velocity and PV fields results in an upward, along-isopycnal eddy PV flux that scales with the surface frictional PV flux driven by the wind. The relationship between the eddy and wind-induced frictional PV flux is nonlocal in time, as the eddy PV flux persists long after the wind forcing is shut off. The ITE's PV flux affects the large-scale flow by driving an eddy-induced transport or bolus velocity down the outcropping isopycnal layer with a magnitude that scales with the Ekman velocity.

On the Path to SunShot. Emerging Opportunities and Challenges in U.S. Solar Manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Donald; Horowitz, Kelsey; Kurup, Parthiv

This report provides insights into photovoltaic (PV) and concentrating solar power (CSP) manufacturing in the context of the U.S. Department of Energy's SunShot Initiative. Although global PV price reductions and deployment have been strong recently, PV manufacturing faces challenges. Slowing rates of manufacturing cost reductions, combined with the relatively low price of incumbent electricity generating sources in most large global PV markets, may constrain profit opportunities for firms and poses a potential challenge to the sustainable operation and growth of the global PV manufacturing base. In the United States, manufacturers also face a factors-of-production cost disadvantage compared with competing nations.more » However, the United States is one of the world's most competitive and innovative countries as well as one of the best locations for PV manufacturing. In conjunction with strong projected PV demand in the United States and across the Americas, these advantages could increase the share of PV technologies produced by U.S. manufacturers as the importance of innovation-driven PV cost reductions increases. Compared with PV, CSP systems are much more complex and require a much larger minimum effective scale, resulting in much higher total CAPEX requirements for system construction, lengthier development cycles, and ultimately higher costs of energy produced. The global lack of consistent CSP project development creates challenges for companies that manufacture specialty CSP components, and the potential lack of a near-term U.S. market could hinder domestic CSP manufacturers. However, global and U.S. CSP deployment is expected to expand beyond 2020, and U.S. CSP manufacturers could benefit from U.S. innovation advantages similar to those associated with PV. Expansion of PV and CSP manufacturing also presents U.S. job-growth opportunities.« less

Rooftop Solar Photovoltaic Technical Potential in the United States. A Detailed Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagnon, Pieter; Margolis, Robert; Melius, Jennifer

2016-01-01

How much energy could be generated if PV modules were installed on all of the suitable roof area in the nation? To answer this question, we first use GIS methods to process a lidar dataset and determine the amount of roof area that is suitable for PV deployment in 128 cities nationwide, containing 23% of U.S. buildings, and provide PV-generation results for a subset of those cities. We then extend the insights from that analysis to the entire continental United States. We develop two statistical models--one for small buildings and one for medium and large buildings--and populate them with geographicmore » variables that correlate with rooftop's suitability for PV. We simulate the productivity of PV installed on the suitable roof area, and present the technical potential of PV on both small buildings and medium/large buildings for every state in the continental US. Within the 128 cities covered by lidar data, 83% of small buildings have a location suitable for a PV installation, but only 26% of the total rooftop area of small buildings is suitable for development. The sheer number of buildings in this class, however, gives small buildings the greatest technical potential. Small building rooftops could accommodate 731 GW of PV capacity and generate 926 TWh/year of PV energy, approximately 65% of rooftop PV's total technical potential. We conclude by summing the PV-generation results for all building sizes and therefore answering our original question, estimating that the total national technical potential of rooftop PV is 1,118 GW of installed capacity and 1,432 TWh of annual energy generation. This equates to 39% of total national electric-sector sales.« less

Rooftop Solar Photovoltaic Technical Potential in the United States

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagnon, Pieter; Margolis, Robert; Melius, Jennifer

2016-01-01

How much energy could we generate if PV modules were installed on all of the suitable roof area in the nation? To answer this question, we first use GIS methods to process a lidar dataset and determine the amount of roof area that is suitable for PV deployment in 128 cities nationwide, containing 23% of U.S. buildings, and provide PV-generation results for a subset of those cities. We then extend the insights from that analysis to the entire continental United States. We develop two statistical models -- one for small buildings and one for medium and large buildings -- andmore » populate them with geographic variables that correlate with rooftop's suitability for PV. We simulate the productivity of PV installed on the suitable roof area, and present the technical potential of PV on both small buildings and medium/large buildings for every state in the continental US. Within the 128 cities covered by lidar data, 83% of small buildings have a location suitable for a PV installation, but only 26% of the total rooftop area of small buildings is suitable for development. The sheer number of buildings in this class, however, gives small buildings the greatest technical potential. Small building rooftops could accommodate 731 GW of PV capacity and generate 926 TWh/year of PV energy, approximately 65% of rooftop PV's total technical potential. We conclude by summing the PV-generation results for all building sizes and therefore answering our original question, estimating that the total national technical potential of rooftop PV is 1,118 GW of installed capacity and 1,432 TWh of annual energy generation. This equates to 39% of total national electric-sector sales.« less

Structural basis of potassium activation in plant asparaginases.

PubMed

Ajewole, Ebenezer; Santamaria-Kisiel, Liliana; Pajak, Agnieszka; Jaskolski, Mariusz; Marsolais, Frédéric

2018-04-01

l-asparaginases (EC 3.5.1.1) play an important role in nitrogen mobilization in plants. Here, we investigated the biochemical and biophysical properties of potassium-dependent (PvAspG1) and potassium-independent (PvAspG-T2) l-asparaginases from Phaseolus vulgaris. Our previous studies revealed that PvAspG1 requires potassium for catalytic activation and its crystal structure suggested that Ser-118 in the activation loop plays a critical role in coordinating the metal cation. This amino acid residue is replaced by isoleucine in PvAspG-T2. Reciprocal mutants of the enzymes were produced and the effect of the amino acid substitution on the kinetic parameters, allosteric effector binding, secondary structure conformation, and pH profile were studied. Introduction of the serine residue conferred potassium activation in PvAspG-T2. Conversely, the PvAspG1-S118I mutant could no longer be activated by potassium. PvAspG1 and the PvAspG-T2-I117S mutant had a similar half-maximal effective concentration (EC 50 ) value for potassium activation, between 0.1 and 0.3 mm. Potassium binding elicited a similar conformational change in PvAspG1 and PvAspG-T2-I117S, as studied by circular dichroism. However, no change in conformation was observed for PvAspG-T2 and PvAspG1-S118I. Analysis of kinetic parameters in function of pH indicated that potassium activation mediated by Ser-118 influences the ionization of specific functional groups in the enzyme-substrate complex. Together, the results indicate that Ser-118 of PvAspG1 is essential and sufficient for potassium activation in plant l-asparaginases. ENZYME: l-Asparaginase (EC 3.5.1.1). © 2018 Federation of European Biochemical Societies.

Development and Testing of a Prototype Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) has developed and tested a prototype 2 kW DC grid-tied photovoltaic (PV) power system at the Center. The PV system has generated in excess of 6700 kWh since operation commenced in July 2006. The PV system is providing power to the GRC grid for use by all. Operation of the prototype PV system has been completely trouble free. A grid-tied PV power system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. Based upon the success of the prototype PV system, additional PV power system expansion at GRC is under consideration. The prototype grid-tied PV power system was successfully designed and developed which served to validate the basic principles described, and the theoretical work that was performed. The report concludes that grid-tied photovoltaic power systems are reliable, maintenance free, long life power systems, and are of significant value to NASA and the community.

Ceiling-mounted personalized ventilation system integrated with a secondary air distribution system--a human response study in hot and humid climate.

PubMed

Yang, B; Sekhar, S C; Melikov, A K

2010-08-01

The benefits of thermal comfort and indoor air quality with personalized ventilation (PV) systems have been demonstrated in recent studies. One of the barriers for wide spread acceptance by architects and HVAC designers has been attributed to challenges and constraints faced in the integration of PV systems with the work station. A newly developed ceiling-mounted PV system addresses these challenges and provides a practical solution while retaining much of the apparent benefits of PV systems. Assessments of thermal environment, air movement, and air quality for ceiling-mounted PV system were performed with tropically acclimatized subjects in a Field Environmental Chamber. Thirty-two subjects performed normal office work and could choose to be exposed to four different PV airflow rates (4, 8, 12, and 16 L/s), thus offering themselves a reasonable degree of individual control. Ambient temperatures of 26 and 23.5 degrees C and PV air temperatures of 26, 23.5, and 21 degrees C were employed. The local and whole body thermal sensations were reduced when PV airflow rates were increased. Inhaled air temperature was perceived cooler and perceived air quality and air freshness improved when PV airflow rate was increased or temperature was reduced. The newly developed ceiling-mounted PV system offers a practical solution to the integration of PV air terminal devices (ATDs) in the vicinity of the workstation. By remotely locating the PV ATDs on the ceiling directly above the occupants and under their control, the conditioned outdoor air is now provided to the occupants through the downward momentum of the air. A secondary air-conditioning and air distribution system offers additional cooling in the room and maintains a higher ambient temperature, thus offering significant benefits in conserving energy. The results of this study provide designers and consultants with needed knowledge for design of PV systems.

Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

DTIC Science & Technology

2015-07-01

24 6.6 DEMONSTRATION 6: PV + STORAGE SUPPORT MANAGING VARIABLE SOLAR ...Table 2. Energy generated by solar PV for 1 month. .......................................................... 23 Table 3. NG generators energy...saving with solar PV . ........................................................ 24 Table 4. NG generators fuel saving with solar PV

The potential role of hematocrit control on symptom burden among polycythemia vera patients: Insights from the CYTO-PV and MPN-SAF patient cohorts.

PubMed

Scherber, Robyn Marie; Geyer, Holly Lynn; Dueck, Amylou C; Kosiorek, Heidi E; Finazzi, Guido; Cavazzina, Riccardo; Masciulli, Arianna; Scarano, Marco; Vannucchi, Alessandro M; Mesa, Ruben A; Barbui, Tiziano

2017-06-01

Current guidelines suggest that polycythemia vera (PV) patients maintain a strict hematocrit less than 45%. However, to date, little is known about the relationship between HCT control and PV- related symptom burden. In this study, PV patient data was analyzed from the CYTO PV trial (n = 224) and the MPN-SAF study cohort (n = 645). No significant differences in symptom burden were seen at the 6 and 12 month follow-up when evaluating prospective hematocrit control in the CYTO PV cohort. Patients in the MPN-SAF cohort with a worst item score of greater than 5/10 on the Myeloproliferative Neoplasm Symptom Total Symptom Score had a significantly lower mean hematocrit (p = .0376). These findings suggest a relationship between traditional aggressive therapy for PV and increased symptom burden with prolonged therapy. Thus, symptom burden should be considered when contemplating the choice of therapy in the second-line setting for PV.

Integrated application of combined cooling, heating and power poly-generation PV radiant panel system of zero energy buildings

NASA Astrophysics Data System (ADS)

Yin, Baoquan

2018-02-01

A new type of combined cooling, heating and power of photovoltaic radiant panel (PV/R) module was proposed, and applied in the zero energy buildings in this paper. The energy system of this building is composed of PV/R module, low temperature difference terminal, energy storage, multi-source heat pump, energy balance control system. Radiant panel is attached on the backside of the PV module for cooling the PV, which is called PV/R module. During the daytime, the PV module was cooled down with the radiant panel, as the temperature coefficient influence, the power efficiency was increased by 8% to 14%, the radiant panel solar heat collecting efficiency was about 45%. Through the nocturnal radiant cooling, the PV/R cooling capacity could be 50 W/m2. For the multifunction energy device, the system shows the versatility during the heating, cooling and power used of building utilization all year round.

Optimal Solar PV Arrays Integration for Distributed Generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omitaomu, Olufemi A; Li, Xueping

2012-01-01

Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introducemore » quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.« less

Affordable remote-area power supply in the Philippines

NASA Astrophysics Data System (ADS)

Heruela, C. S.

The feasibility of photovoltaic (PV) systems for electrifying remote areas of the Philippines is discussed. In particular, a technical description is given of those PV systems that are appropriate to the needs of remote, but populated, rural areas and have been developed as part of the Philippine-German Solar Energy Project. Details are provided of a financing scheme, piloted by the Project on an unelectrified island, to make PV systems affordable to rural users. An analysis is presented of the potential of large-scale applications of PV systems in developing countries such as the Philippines, and a description is provided of current efforts to promote the use of such technology. A storage battery is identified as an essential component of a PV system. As a consequence, the wide use of PV systems will have a very significant impact on the market for storage batteries in countries embarking on PV-utilization programmes. It is clear, therefore, that battery manufacturers should take an interest in future development in PV applications.

Determination of plasma volume by indocyanine green--validation of the method and use in patients after cardiopulmonary bypass.

PubMed

Menth-Meier, S E; Imoberdorf, R; Regli, B; Kipfer, B; Turgay, M; Ballmer, P E

2001-05-01

Validation of plasma volume (PV) determination by indocyanine green (ICG) in comparison to the gold-standard method with radioiodinated albumin, and investigation of the effect of commonly used plasma expanders (albumin, hydroxyethyl starch, and polygelatine) on PV in the early postoperative phase in patients undergoing cardiac surgery. Prospective clinical study. Department of medicine and intensive care unit at a university hospital. Ten healthy volunteers and 21 patients after elective open-heart surgery. PV of subjects was measured by i.v. injecting 5 microCi [125I]albumin (I-ALB). One hour later, PV was determined by a peripheral i. v. injection of 0.25 mg/kg body weight ICG (ICG1). In five subjects PV was measured repeatedly by ICG (ICG2) 1 h after ICG1. Mean PV of I-ALB and ICG1 or ICG2 showed consistent results. Further, we investigated central vs peripheral intravenous injection of ICG in six patients after open-heart surgery compared to [125I]albumin. There was no difference between mean PV measured by [125I]albumin and peripheral ICG (P = 0.40). PV determined by central injection of ICG was significantly higher than by the other methods. In 15 patients PV was determined by [125I]albumin. Thereafter, patients were randomly divided into three groups. Group ALB was infused with 1.75 ml/kg body weight human albumin 20%, group HAES with 5.25 ml/kg body weight hydroxyethyl starch 6%, and group HAEM with 7.0 ml/kg body weight polygelatine 3.5%. PV was measured 1 h and 4 h after infusion by ICG. There were no significant changes in PV between the groups. PV determination by peripheral i. v. injection of ICG produced reliable and consistent results when a reactive hyperaemia was produced by a tourniquet prior to injection. Therefore, central venous injection of ICG may not be prerequisite for precise measurements of PV. The expected acute increase in PV after infusion of commonly used plasma expanders after cardiac surgery was not found.

Prognostics and health management of photovoltaic systems

DOEpatents

Johnson, Jay; Riley, Daniel

2018-04-10

The various technologies presented herein relate to providing prognosis and health management (PHM) of a photovoltaic (PV) system. A PV PHM system can eliminate long-standing issues associated with detecting performance reduction in PV systems. The PV PHM system can utilize an ANN model with meteorological and power input data to facilitate alert generation in the event of a performance reduction without the need for information about the PV PHM system components and design. Comparisons between system data and the PHM model can provide scheduling of maintenance on an as-needed basis. The PHM can also provide an approach for monitoring system/component degradation over the lifetime of the PV system.

Stabilized PV system

DOEpatents

Dinwoodie, Thomas L.

2002-12-17

A stabilized PV system comprises an array of photovoltaic (PV) assemblies mounted to a support surface. Each PV assembly comprises a PV module and a support assembly securing the PV module to a position overlying the support surface. The array of modules is circumscribed by a continuous, belt-like perimeter assembly. Cross strapping, extending above, below or through the array, or some combination of above, below and through the array, secures a first position along the perimeter assembly to at least a second position along the perimeter assembly thereby stabilizing the array against wind uplift forces. The first and second positions may be on opposite sides on the array.

Determining the Impact of Steady-State PV Fault Current Injections on Distribution Protection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seuss, John; Reno, Matthew J.; Broderick, Robert Joseph

This report investigates the fault current contribution from a single large PV system and the impact it has on existing distribution overcurrent protection devices. Assumptions are made about the modeling of the PV system under fault to perform exhaustive steady - state fault analyses throughout distribution feeder models. Each PV interconnection location is tested to determine how the size of the PV system affects the fault current measured by each protection device. This data is then searched for logical conditions that indicate whether a protection device has operated in a manner that will cause more customer outages due to themore » addition of the PV system. This is referred to as a protection issue , and there are four unique types of issues that have been identified in the study. The PV system size at which any issues occur are recorded to determine the feeder's PV hosting capacity limitations due to interference with protection settings. The analysis is carried out on six feeder models. The report concludes with a discussion of the prevalence and cause of each protection issue caused by PV system fault current.« less

Arsenic enhanced plant growth and altered rhizosphere characteristics of hyperaccumulator Pteris vittata.

PubMed

Xu, Jia Yi; Li, Hong Bo; Liang, Shuang; Luo, Jun; Ma, Lena Q

2014-11-01

We investigated the effects of arsenic species on As accumulation, plant growth and rhizospheric changes in As-hyperaccumulator Pteris vittata (PV). PV was grown for 60-d in a soil spiked with 200 mg kg(-1) arsenate (AsV-soil) or arsenite (AsIII-soil). Diffusive gradients in thin-films technique (DGT) were used to monitor As uptake by PV. Interestingly AsIII-soil produced the highest PV biomass at 8.6 g plant(-1), 27% and 46% greater than AsV-soil and the control. Biomass increase was associated with As-induced P uptake by PV. Although AsIII was oxidized to AsV during the experiment, As species impacted As accumulation by PV, with 17.5% more As in AsIII-soil than AsV-soil (36 vs. 31 mg plant(-1)). As concentration in PV roots was 30% higher in AsV-soil whereas As concentration in PV fronds was 7.9% greater in AsIII-soil, suggesting more rapid translocation of AsIII than AsV. These findings were important to understand the mechanisms of As uptake, accumulation and translocation by PV. Published by Elsevier Ltd.

Novel Methods to Determine Feeder Locational PV Hosting Capacity and PV Impact Signatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reno, Matthew J.; Coogan, Kyle; Seuss, John

Often PV hosting capacity analysis is performed for a limited number of distribution feeders. For medium - voltage distribution feeders, previous results generally analyze less than 20 feeders, and then the results are extrapolated out to similar types of feeders. Previous hosting capacity research has often focused on determining a single value for the hosting capacity for the entire feeder, whereas this research expands previous hosting capacity work to investigate all the regions of the feeder that may allow many different hosting capacity values wit h an idea called locational hosting capacity (LHC)to determine the largest PV size that canmore » be interconnected at different locations (buses) on the study feeders. This report discusses novel methods for analyzing PV interconnections with advanced simulati on methods. The focus is feeder and location - specific impacts of PV that determine the locational PV hosting capacity. Feeder PV impact signature are used to more precisely determine the local maximum hosting capacity of individual areas of the feeder. T he feeder signature provides improved interconnection screening with certain zones that show the risk of impact to the distribution feeder from PV interconnections.« less

The Predictive Ability of PV-ACO2 Gap and PV-ACO2/CA-VO2 Ratio in Shock: A Prospective, Cohort Study.

PubMed

Shaban, Mohammad; Salahuddin, Nawal; Kolko, Mohammad Raed; Sharshir, Moh'd; AbuRageila, Mohannad; AlHussain, Ahmed

2017-04-01

Compromised tissue oxygenation leads to anaerobiosis, leading to organ failure and death. This study attempts to demonstrate the predictive abilities of the Pv-aCO2 gap and Pv-aCO2/Ca-vO2 ratio in shock patients undergoing resuscitation. In a prospective study, consecutive patients with shock were included. Timed measurements of Pv-aCO2 gap, ScvO2, lactate, and Pv-aCO2/ Ca-vO2 ratio were obtained. The association between the mortality and each variable at all intervals was analyzed. Receiver operating characteristics curves were built. Fifty patients were enrolled. Intensive care unit survivors had a higher Pv-aCO2/ Ca-vO2 ratio at time 0 (0.21, interquartile range [IQR] 0.14 vs. 0.27, IQR 0.38, P = 0.032) and at 3 h (0.27, IQR 0.08 vs. 0.21, IQR 0.12, P = 0.035).Twenty-eight day survival was higher in patients with a low Pv-aCO2 gap at time 0 (7.5, IQR 7 vs. 4.8, IQR 5, P = 0.007).Baseline Pv-aCO2 gap and Pv-aCO2/Ca-vO2 ratio showed good ability to predict 28-day mortality as seen by AUC 0.728 (95% CI 0.578-0.877, P = 0.007) and 0.711 (95% CI 0.563-0.860, P = 0.013). A cut-off point of Pv-aCO2 gap ≥6 mm Hg identified 28-day mortality (75% vs. 45.5%, P = 0.034). The best cutoff values, at baseline, to predict 28-day mortality were 0.25 for the Pv-aCO2/Ca-vO2 ratio (sensitivity 58%, specificity 85%, LR+ 3.86, LR- 0.49) and 6.3 for the Pv-aCO2 gap (sensitivity 58%, specificity 79%, LR+ 2.76, LR- 0.53). This study suggests that Pv-aCO2 gap and Pv-aCO2/Ca-vO2 ratio are discriminating predictors of 28-day mortality and can be used to provide supplementary information during resuscitation in shock.

NATIONAL ASSESSMENT OF EMISSIONS REDUCTION IMPACT FROM ROOFTOP PV

EPA Science Inventory

This effort will determine the emissions impacts to the U.S. PV generated electricity when PV systems are installed on building rooftops and employed as demand-side power supplies. The national assessment will be based on data provided by existing rooftop PV systems that have be...

2015 International PV Quality Assurance Task Force (PVQAT) Workshop |

Science.gov Websites

Photovoltaic Research | NREL International PV Quality Assurance Task Force (PVQAT) Workshop 2015 International PV Quality Assurance Task Force (PVQAT) Workshop Wednesday, February 25, 2015 Chairs : Tony Sample and Masaaki Yamamichi The 2015 International PV Quality Assurance Task Force (PVQAT

Testing for PV Reliability (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, S.; Bansal, S.

The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

2017 NREL Photovoltaic Reliability Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, Sarah

NREL's Photovoltaic (PV) Reliability Workshop (PVRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology -- both critical goals for moving PV technologies deeper into the electricity marketplace.

Low Illumination Light (LIL) Solar Cells: Indoor and Monochromatic Light Harvesting

DTIC Science & Technology

2015-11-01

photovoltaic ( PV ) solar cells under low intensity and narrow light spectrum conditions has not been clearly examined. PV operating values under 1 sun...3. PV Fundamental Losses under Low-Light Conditions 5 4. Experiment Setup 9 4.1 Materials 9 4.1.1 Light Sources and Spectra 9 4.1.2 PV Solar ...http://www.mjinc.com/newsArticle2012_Mar15.html ..........................4 Fig. 4 Three energy and power densities ranges for PV solar cells

PV System Component Fault and Failure Compilation and Analysis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Lavrova, Olga; Gooding, Renee Lynne

This report describes data collection and analysis of solar photovoltaic (PV) equipment events, which consist of faults and fa ilures that occur during the normal operation of a distributed PV system or PV power plant. We present summary statistics from locations w here maintenance data is being collected at various intervals, as well as reliability statistics gathered from that da ta, consisting of fault/failure distributions and repair distributions for a wide range of PV equipment types.

Space Station Freedom solar array panels plasma interaction test facility

NASA Technical Reports Server (NTRS)

Martin, Donald F.; Mellott, Kenneth D.

1989-01-01

The Space Station Freedom Power System will make extensive use of photovoltaic (PV) power generation. The phase 1 power system consists of two PV power modules each capable of delivering 37.5 KW of conditioned power to the user. Each PV module consists of two solar arrays. Each solar array is made up of two solar blankets. Each solar blanket contains 82 PV panels. The PV power modules provide a 160 V nominal operating voltage. Previous research has shown that there are electrical interactions between a plasma environment and a photovoltaic power source. The interactions take two forms: parasitic current loss (occurs when the currect produced by the PV panel leaves at a high potential point and travels through the plasma to a lower potential point, effectively shorting that portion of the PV panel); and arcing (occurs when the PV panel electrically discharges into the plasma). The PV solar array panel plasma interaction test was conceived to evaluate the effects of these interactions on the Space Station Freedom type PV panels as well as to conduct further research. The test article consists of two active solar array panels in series. Each panel consists of two hundred 8 cm x 8 cm silicon solar cells. The test requirements dictated specifications in the following areas: plasma environment/plasma sheath; outgassing; thermal requirements; solar simulation; and data collection requirements.

Contrasting skeletal phenotypes in mice with an identical mutation targeted to thyroid hormone receptor alpha1 or beta.

PubMed

O'Shea, Patrick J; Bassett, J H Duncan; Sriskantharajah, Srividya; Ying, Hao; Cheng, Sheue-yann; Williams, Graham R

2005-12-01

Thyroid hormone (T(3)) regulates bone turnover and mineralization in adults and is essential for skeletal development. Surprisingly, we identified a phenotype of skeletal thyrotoxicosis in T(3) receptor beta(PV) (TRbeta(PV)) mice in which a targeted frameshift mutation in TRbeta results in resistance to thyroid hormone. To characterize mechanisms underlying thyroid hormone action in bone, we analyzed skeletal development in TRalpha1(PV) mice in which the same PV mutation was targeted to TRalpha1. In contrast to TRbeta(PV) mice, TRalpha1(PV) mutants exhibited skeletal hypothyroidism with delayed endochondral and intramembranous ossification, severe postnatal growth retardation, diminished trabecular bone mineralization, reduced cortical bone deposition, and delayed closure of the skull sutures. Skeletal hypothyroidism in TRalpha1(PV) mutants was accompanied by impaired GH receptor and IGF-I receptor expression and signaling in the growth plate, whereas GH receptor and IGF-I receptor expression and signaling were increased in TRbeta(PV) mice. These data indicate that GH receptor and IGF-I receptor are physiological targets for T(3) action in bone in vivo. The divergent phenotypes observed in TRalpha1(PV) and TRbeta(PV) mice arise because the pituitary gland is a TRbeta-responsive tissue, whereas bone is TRalpha responsive. These studies provide a new understanding of the complex relationship between central and peripheral thyroid status.

Efferent connections of the parvalbumin-positive (PV1) nucleus in the lateral hypothalamus of rodents

PubMed Central

Celio, Marco R.; Babalian, Alexander; Ha, Quan Hue; Eichenberger, Simone; Clément, Laurence; Marti, Christiane; Saper, Clifford B.

2013-01-01

A solitary cluster of parvalbumin-positive neurons - the PV1-nucleus - has been observed in the lateral hypothalamus of rodents. In the present study, we mapped the efferent connections of the rodent PV1-nucleus using non-specific antero- and retrograde tracers in rats, and chemoselective, Cre-dependent viral constructs in parvalbumin-Cre mice. In both species, the PV1-nucleus was found to project mainly to the periaqueductal grey matter (PAG), preponderantly ipsilateral. Indirectly in rats and directly in mice, a discrete, longitudinally- orientated cylindrical column of terminal fields (PV1-CTF) was identified ventrolateral to the aqueduct on the edge of the PAG. The PV1-CTF, which is particularly dense in the rostral portion, located in the supraoculomotor nucleus (Su3), is spatially interrupted over a short stretch at the level of the trochlear nucleus and abuts caudally on a second parvalbum in-positive (PV2) nucleus. The rostral and the caudal portions of the PV1-CTF consist of axonal endings that stem from scattered neurons throughout the PV1-nucleus. Minor terminal fields were identified in a crescentic column of the lateral PAG, as well as in the Edinger-Westphal-, the lateral habenular- and the laterodorsal tegmental nuclei. So far no obvious functions can be attributed to this small, circumscribed column ventrolateral to the aqueduct, the prime target of the PV1-nucleus. PMID:23787784

Degradation Analysis of Field-Exposed Photovoltaic Modules with Non-Fluoropolymer-Based Backsheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kempe, Michael D; Fairbrother, Andrew; Julien, Scott

The selection of polymeric materials utilized in photovoltaic (PV) modules has changed relatively little since the inception of the PV industry, with ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), and fluoropolymer-based laminates being the most widely adopted primary components of the encapsulant and backsheet materials. The backsheet must serve to electrically insulate the solar cells and protect them from the effects of weathering. Due to continued downward pressure on cost, other polymeric materials are being formulated to withstand outdoor exposure for use in backsheets to replace either the PET film, the fluoropoymer film, or both. Because of their relatively recent deployment,more » less is known about their reliability and if they are durable enough to fulfill the greater than or equal to 25 year warranties of current PV modules. This work presents a degradation analysis of field-exposed modules with polyamide- and polyester-based backsheets. Modules were exposed for up to five years in different geographic locations: USA (Maryland, Ohio), China, and Italy. Surface and cross-sectional analysis included visual inspection, colorimetry, glossimetry, and Fourier-transform infrared spectroscopy. Each module experienced different types of degradation depending on the exposure site, even for the same material and module brand. For instance, the polyamide-based backsheet experienced hairline cracking and greater yellowing and chemical changes in China (Changsu, humid subtropical climate), while in Italy (Rome, hot-summer Mediterranean climate) it underwent macroscopic cracking and greater losses in gloss. Spectroscopic studies have permitted identification of degradation products and changes in polymer structure over time. Comparisons are made to fielded modules with fluoropolymer-based backsheets, as well as backsheet materials in accelerated laboratory exposures. Implications for qualification testing and service life prediction of the non-fluoropolymer-based backsheets are discussed.« less

Degradation analysis of field-exposed photovoltaic modules with non-fluoropolymer-based backsheets

NASA Astrophysics Data System (ADS)

Fairbrother, Andrew; Julien, Scott; Wan, Kai-Tak; Ji, Liang; Boyce, Kenneth; Merzlic, Sebastien; Lefebvre, Amy; O'Brien, Greg; Wang, Yu; Bruckman, Laura; French, Roger; Kempe, Michael; Gu, Xiaohong

2017-08-01

The selection of polymeric materials utilized in photovoltaic (PV) modules has changed relatively little since the inception of the PV industry, with ethylene-vinyl acetate (EVA), polyethylene terephthalate (PET), and fluoropolymer-based laminates being the most widely adopted primary components of the encapsulant and backsheet materials. The backsheet must serve to electrically insulate the solar cells and protect them from the effects of weathering. Due to continued downward pressure on cost, other polymeric materials are being formulated to withstand outdoor exposure for use in backsheets to replace either the PET film, the fluoropoymer film, or both. Because of their relatively recent deployment, less is known about their reliability and if they are durable enough to fulfill the >=25 year warranties of current PV modules. This work presents a degradation analysis of field-exposed modules with polyamide- and polyester-based backsheets. Modules were exposed for up to five years in different geographic locations: USA (Maryland, Ohio), China, and Italy. Surface and cross-sectional analysis included visual inspection, colorimetry, glossimetry, and Fourier-transform infrared spectroscopy. Each module experienced different types of degradation depending on the exposure site, even for the same material and module brand. For instance, the polyamide-based backsheet experienced hairline cracking and greater yellowing and chemical changes in China (Changsu, humid subtropical climate), while in Italy (Rome, hot-summer Mediterranean climate) it underwent macroscopic cracking and greater losses in gloss. Spectroscopic studies have permitted identification of degradation products and changes in polymer structure over time. Comparisons are made to fielded modules with fluoropolymer-based backsheets, as well as backsheet materials in accelerated laboratory exposures. Implications for qualification testing and service life prediction of the non-fluoropolymer-based backsheets are discussed.

A reappraisal of the benefit-risk profile of hydroxyurea in polycythemia vera: A propensity-matched study.

PubMed

Barbui, Tiziano; Vannucchi, Alessandro Maria; Finazzi, Guido; Finazzi, Maria Chiara; Masciulli, Arianna; Carobbio, Alessandra; Ghirardi, Arianna; Tognoni, Gianni

2017-11-01

The use of hydroxyurea (HU) as first line therapy in polycythemia vera (PV) has been criticized because no solid demonstration that this drug prevents thrombosis or prolongs survival has been so far produced. Here we present the outcomes of a large cohort of patients with PV included in the European Collaborative Low-dose Aspirin (ECLAP) study. We selected 1,042 patients who, during the follow-up, had received only phlebotomy (PHL) or HU to maintain the hematocrit level < 45%. To assure comparability, we conducted a propensity score matching analysis. The two groups (PHL n = 342 and HU n = 681) were well balanced for the parameters included in the propensity score (overall balance: χ 2  = 2.44, P = 0.964). Over a comparable period of follow-up (PHL = 29.9 vs. HU = 34.7 months), we documented an advantage of HU over PHL consistently significant with respect to the incidence of fatal/non-fatal cardiovascular (CV) events (5.8 vs. 3.0 per 100 person-years in PHL vs. HU group, P = 0.002) and myelofibrosis transformation that was only experienced by patients of PHL group. Evolution to acute leukemia was registered in three patients (two in PHL and one in HU group). The excess of mortality and total CV events in the PHL patients was restricted to the high-risk group, and, compared with HU cases, was significant higher in the PHL patients who failed to reach the hematocrit target < 0.45% (P = 0.000). In conclusion, this analysis provides reliable and qualified estimates of the therapeutic profile of HU and PHL treatments for future experimental studies and for the management of PV in clinical practice. © 2017 Wiley Periodicals, Inc.

Limitations of dormant conduction as a predictor of atrial fibrillation recurrence and pulmonary vein reconnection after catheter ablation.

PubMed

Lin, Frank S; Ip, James E; Markowitz, Steven M; Liu, Christopher F; Thomas, George; Lerman, Bruce B; Cheung, Jim W

2015-05-01

Adenosine (ADO) can uncover dormant conduction following pulmonary vein (PV) isolation. We sought to identify the value of dormant conduction for predicting atrial fibrillation (AF) recurrence and chronic PV reconnection. One hundred fifty-two patients (80 male; age 60 ± 11 years) undergoing PV isolation for AF were studied. After PV isolation, sites of ADO-induced PV reconnection were recorded and targeted with additional ablation. In patients undergoing repeat ablation for recurrent AF, chronic PV reconnection was assessed. Forty-five (30%) patients had ADO-induced PV reconnection following PV isolation. Dormant conduction was successfully eliminated with additional ablation in 41 (91%) of these patients. After follow-up of 598 ± 270 days, 60 (39%) patients had recurrent AF. Dormant PV conduction was not a significant predictor of AF recurrence (hazard ratio 1.51; 95% confidence interval: 0.89-2.56; P = 0.12) although three of four (75%) patients with residual dormant conduction following initial ablation developed recurrent AF. Twenty-six patients with recurrent AF underwent repeat ablation with 52 of 99 (53%) PVs found to have chronic reconnection. Nine of 11 (82%) PVs with dormant conduction and 43 of 88 (49%) PVs without dormant conduction at initial procedure had chronic reconnection at repeat ablation. When additional ablation is performed to eliminate ADO-induced PV reconnection after PV isolation, dormant conduction is not a significant predictor of recurrent AF. Although PVs with dormant conduction at initial procedure may develop chronic reconnection, the majority of PVs that show conduction recovery at repeat ablation occur in nondormant PVs. © 2015 Wiley Periodicals, Inc.

The identification of conduction gaps after pulmonary vein isolation using a new electroanatomic mapping system.

PubMed

Masuda, Masaharu; Fujita, Masashi; Iida, Osamu; Okamoto, Shin; Ishihara, Takayuki; Nanto, Kiyonori; Kanda, Takashi; Tsujimura, Takuya; Matsuda, Yasuhiro; Okuno, Shota; Ohashi, Takuya; Tsuji, Aki; Mano, Toshiaki

2017-11-01

The reconnection of left atrial-pulmonary vein (LA-PV) conduction after the initial procedure of pulmonary vein (PV) isolation is not rare, and is one of the main cause of atrial fibrillation (AF) recurrence after PV isolation. We investigated feasibility of a new ultrahigh-resolution mapping system using a 64-pole small basket catheter for the identification of LA-PV conduction gaps. This prospective study included 31 consecutive patients (20 with persistent AF) undergoing a second ablation after a PV isolation procedure with LA-PV reconnected conduction at any of the 4 PVs. An LA-PV map was created using the mapping system, and ablation was performed at the estimated gap location. The propagation map identified 54 gaps from 39 ipsilateral PV pairs, requiring manual electrogram reannotation for 23 gaps (43%). Gaps at the anterior and carinal regions of left and right ipsilateral PVs required manual electrogram reannotation more frequently than the other regions. The voltage map could identify the gap only in 19 instances (35%). Electrophysiological properties of the gaps (multiple gaps in the same ipsilateral PVs, conduction time, velocity, width, and length) did not differ between those needing and not needing manual electrogram reannotation. During the gap ablation, either the activation sequence alteration or elimination of PV potentials was observed using a circular catheter placed in the PV, suggesting that all the identified gaps were correct. This new electroanatomic mapping system visualized all the LA-PV gaps in patients undergoing a second AF ablation. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Efferent connections of the parvalbumin-positive (PV1) nucleus in the lateral hypothalamus of rodents.

PubMed

Celio, Marco R; Babalian, Alexandre; Ha, Quan Hue; Eichenberger, Simone; Clément, Laurence; Marti, Christiane; Saper, Clifford B

2013-10-01

A solitary cluster of parvalbumin-positive neurons--the PV1 nucleus--has been observed in the lateral hypothalamus of rodents. In the present study, we mapped the efferent connections of the PV1 nucleus using nonspecific antero- and retrograde tracers in rats, and chemoselective, Cre-dependent viral constructs in parvalbumin-Cre mice. In both species, the PV1 nucleus was found to project mainly to the periaqueductal grey matter (PAG), predominantly ipsilaterally. Indirectly in rats and directly in mice, a discrete, longitudinally oriented cylindrical column of terminal fields (PV1-CTF) was identified ventrolateral to the aqueduct on the edge of the PAG. The PV1-CTF is particularly dense in the rostral portion, which is located in the supraoculomotor nucleus (Su3). It is spatially interrupted over a short stretch at the level of the trochlear nucleus and abuts caudally on a second parvalbumin-positive (PV2) nucleus. The rostral and the caudal portions of the PV1-CTF consist of axonal endings, which stem from neurons scattered throughout the PV1 nucleus. Topographically, the longitudinal orientation of the PV1-CTF accords with that of the likewise longitudinally oriented functional modules of the PAG, but overlaps none of them. Minor terminal fields were identified in a crescentic column of the lateral PAG, as well as in the Edinger-Westphal, the lateral habenular, and the laterodorsal tegmental nuclei. So far, no obvious functions have been attributed to this small, circumscribed column ventrolateral to the aqueduct, the prime target of the PV1 nucleus. © 2013 Wiley Periodicals, Inc.

Martian Polar Vortices: Comparison of Reanalyses

NASA Technical Reports Server (NTRS)

Waugh, D. W.; Toigo, A. D.; Guzewich, S. D.; Greybush, S. J.; Wilson, R. J.; Montabone, L.

2016-01-01

The structure and evolution of the Martian polar vortices is examined using two recently available reanalysis systems: version 1.0 of the Mars Analysis Correction Data Assimilation (MACDA) and a preliminary version of the Ensemble Mars Atmosphere Reanalysis System (EMARS). There is quantitative agreement between the reanalyses in the lower atmosphere, where Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) data are assimilated, but there are differences at higher altitudes reflecting differences in the free-running general circulation model simulations used in the two reanalyses. The reanalyses show similar potential vorticity (PV) structure of the vortices: There is near-uniform small PV equatorward of the core of the westerly jet, steep meridional PV gradients on the polar side of the jet core, and a maximum of PV located off of the pole. In maps of 30 sol mean PV, there is a near-continuous elliptical ring of high PV with roughly constant shape and longitudinal orientation from fall to spring. However, the shape and orientation of the vortex varies on daily time scales, and there is not a continuous ring of PV but rather a series of smaller scale coherent regions of high PV. The PV structure of the Martian polar vortices is, as has been reported before, very different from that of Earth's stratospheric polar vortices, but there are similarities with Earth's tropospheric vortices which also occur at the edge of the Hadley Cell, and have near-uniform small PV equatorward of the jet, and a large increase of PV poleward of the jet due to increased stratification.

Martian polar vortices: Comparison of reanalyses

NASA Astrophysics Data System (ADS)

Waugh, D. W.; Toigo, A. D.; Guzewich, S. D.; Greybush, S. J.; Wilson, R. J.; Montabone, L.

2016-09-01

The structure and evolution of the Martian polar vortices is examined using two recently available reanalysis systems: version 1.0 of the Mars Analysis Correction Data Assimilation (MACDA) and a preliminary version of the Ensemble Mars Atmosphere Reanalysis System (EMARS). There is quantitative agreement between the reanalyses in the lower atmosphere, where Mars Global Surveyor (MGS) Thermal Emission Spectrometer (TES) data are assimilated, but there are differences at higher altitudes reflecting differences in the free-running general circulation model simulations used in the two reanalyses. The reanalyses show similar potential vorticity (PV) structure of the vortices: There is near-uniform small PV equatorward of the core of the westerly jet, steep meridional PV gradients on the polar side of the jet core, and a maximum of PV located off of the pole. In maps of 30 sol mean PV, there is a near-continuous elliptical ring of high PV with roughly constant shape and longitudinal orientation from fall to spring. However, the shape and orientation of the vortex varies on daily time scales, and there is not a continuous ring of PV but rather a series of smaller scale coherent regions of high PV. The PV structure of the Martian polar vortices is, as has been reported before, very different from that of Earth's stratospheric polar vortices, but there are similarities with Earth's tropospheric vortices which also occur at the edge of the Hadley Cell, and have near-uniform small PV equatorward of the jet, and a large increase of PV poleward of the jet due to increased stratification.

Organic Photovoltaic Solar Cells | Photovoltaic Research | NREL

Science.gov Websites

Organic Photovoltaic Solar Cells Organic Photovoltaic Solar Cells The National Center for Photovoltaics (NCPV) at NREL has strong complementary research capabilities in organic photovoltaic (OPV) cells pages: High-Efficiency Crystalline PV Polycrystalline Thin-Film PV Perovskite and Organic PV Advanced PV

Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV),

Science.gov Websites

2017-2030 | Solar Research | NREL Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV), 2017-2030 Cost-Reduction Roadmap for Residential Solar Photovoltaics (PV), 2017-2030 This report Office (SETO) residential 2030 photovoltaics (PV) cost target of $0.05 per kilowatt-hour by identifying

Integrating PV in Distributed Grids: Solutions and Technologies Workshop |

Science.gov Websites

Energy Systems Integration Facility | NREL Integrating PV in Distributed Grids: Solutions and Technologies Workshop Integrating PV in Distributed Grids: Solutions and Technologies Workshop In October 2015 (PV) onto the grid. The workshop was held at the Energy Systems Integration Facility. Presenters from

Distributed Optimization and Control | Grid Modernization | NREL

Science.gov Websites

developing an innovative, distributed photovoltaic (PV) inverter control architecture that maximizes PV communications systems to support distribution grid operations. The growth of PV capacity has introduced prescribed limits, while fast variations in PV output tend to cause transients that lead to wear-out of

Photovoltaic Lifetime Project | Photovoltaic Research | NREL

Science.gov Websites

PV & Solar Resource Testing Accelerated Testing & Analysis Systems Engineering Project Sandia National Laboratories' PV Performance Modeling Collaborative website. Jinko Solar. PV systems mounted on the ground. Jinko Solar PV Lifetime installation at NREL. need-alt Light-induced degradation

Photovoltaic Module Reliability Workshop 2011: February 16-17, 2011

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, S.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2014: February 25-26, 2014

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, S.

2014-02-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2013: February 26-27, 2013

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, S.

2013-10-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Photovoltaic Module Reliability Workshop 2010: February 18-19, 2010

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, J.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

2016 NREL Photovoltaic Module Reliability Workshop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, Sarah

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology - both critical goals for moving PV technologies deeper into the electricity marketplace.

2015 NREL Photovoltaic Module Reliability Workshops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, Sarah

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Intermittent Renewable Management Pilot Phase 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kiliccote, Sila; Homan, Gregory; Anderson, Robert

The Intermittent Renewable Management Pilot - Phase 2 (IRM2) was designed to study the feasibility of demand-side resources to participate into the California Independent System Operator (CAISO) wholesale market as proxy demand resources (PDR). The pilot study focused on understanding the issues related with direct participation of third-parties and customers including customer acceptance; market transformation challenges (wholesale market, technology); technical and operational feasibility; and value to the rate payers, DR resource owners and the utility on providing an enabling mechanism for DR resources into the wholesale markets. The customer had the option of committing to either three contiguous hour blocksmore » for 24 days or six contiguous hours for 12 days a month with day-ahead notification that aligned with the CAISO integrated forward market. As a result of their being available, the customer was paid $10/ kilowatt (kW)-month for capacity in addition to CAISO energy settlements. The participants were limited to no more than a 2 megawatt (MW) capacity with a six-month commitment. Four participants successfully engaged in the pilot. In this report, we provide the description of the pilot, participant performance results, costs and value to participants as well as outline some of the issues encountered through the pilot. Results show that participants chose to participate with storage and the value of CAISO settlements were significantly lower than the capacity payments provided by the utility as incentive payments. In addition, this pilot revealed issues both on the participant side and system operations side. These issues are summarized in the report.The Intermittent Renewable Management Pilot - Phase 2 (IRM2) was designed to study the feasibility of demand-side resources to participate into the California Independent System Operator (CAISO) wholesale market as proxy demand resources (PDR). The pilot study focused on understanding the issues related with direct participation of third-parties and customers including customer acceptance; market transformation challenges (wholesale market, technology); technical and operational feasibility; and value to the rate payers, DR resource owners and the utility on providing an enabling mechanism for DR resources into the wholesale markets.« less

Zinc Bromide Flow Battery Installation for Islanding and Backup Power

DTIC Science & Technology

2016-09-18

ability to control the generation has become more difficult with the increase of renewable energy systems such as solar photovoltaics ( PV ) and wind... PV and Inverter Room Building 6311 Rooftop Solar PV 30kW 232kW STC PV Array B5-PS2T33 Pad Switchboard ZnBr Energy Storage System (ESS) PowerBoxEnergy...Agreement • 1.5 MW of Photovoltaic • PV Parking lot lights • 24 Solar Thermal systems including the Combat Training Tank (Pool) Energy/Water Efficiency

Recent advances in the PV-CSP hybrid solar power technology

NASA Astrophysics Data System (ADS)

Ju, Xing; Xu, Chao; Han, Xue; Zhang, Hui; Wei, Gaosheng; Chen, Lin

2017-06-01

Photovoltaic - Concentrated Solar Power (PV-CSP) hybrid technology is considered to be an important future research trend in solar energy engineering. The development of the PV-CSP hybrid technology accelerates in recent years with the rapid maturation of photovoltaics (PV) and concentrated solar power (CSP). This paper presents the recent advances on PV-CSP technology, including different technologies based on new dispatch strategies, Organic Rankine Cycles, spectral beam filters and so on. The research status and the hybrid system performance of the recent researches are summarized, aimed to provide an extended recognition on the PV-CSP hybrid technology. The advantages and limitations of the hybrid system are concluded according to the researches reviewed.

Numerical investigation of the thermal and electrical performances for combined solar photovoltaic/thermal (PV/T) modules based on internally extruded fin flow channel

NASA Astrophysics Data System (ADS)

Deng, Y. C.; Li, Q. P.; Wang, G. J.

2017-11-01

A solar photovoltaic/thermal (PV/T) module based on internally extruded fin flow channel was investigated numerically in this paper. First of all, the structures of the thin plate heat exchanger and the PV/T module were presented. Then, a numerical model of the PV/T module considering solar irradiation, fluid flow and heat transfer was developed to analyze the performance of the module. Finally, the steady electrical and thermal efficiencies of the PV/T module at different inlet water temperatures and mass flow rates were achieved. These numerical results supply theory basis for practical application of the PV/T module.

Technologies to Increase PV Hosting Capacity in Distribution Feeders: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Gotseff, Peter

This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for amore » low cost. Additionally, the tool developed for these studies is described.« less

Technologies to Increase PV Hosting Capacity in Distribution Feeders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry; Gotseff, Peter

This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for amore » low cost. Additionally, the tool developed for these studies is described.« less

On Distributed PV Hosting Capacity Estimation, Sensitivity Study, and Improvement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Fei; Mather, Barry

This paper first studies the estimated distributed PV hosting capacities of seventeen utility distribution feeders using the Monte Carlo simulation based stochastic analysis, and then analyzes the sensitivity of PV hosting capacity to both feeder and photovoltaic system characteristics. Furthermore, an active distribution network management approach is proposed to maximize PV hosting capacity by optimally switching capacitors, adjusting voltage regulator taps, managing controllable branch switches and controlling smart PV inverters. The approach is formulated as a mixed-integer nonlinear optimization problem and a genetic algorithm is developed to obtain the solution. Multiple simulation cases are studied and the effectiveness of themore » proposed approach on increasing PV hosting capacity is demonstrated.« less

The hrpZ Gene of Pseudomonas syringae pv. phaseolicola Enhances Resistance to Rhizomania Disease in Transgenic Nicotiana benthamiana and Sugar Beet

PubMed Central

Pavli, Ourania I.; Kelaidi, Georgia I.; Tampakaki, Anastasia P.; Skaracis, George N.

2011-01-01

To explore possible sources of transgenic resistance to the rhizomania-causing Beet necrotic yellow vein virus (BNYVV), Nicotiana benthamiana plants were constructed to express the harpin of Pseudomonas syringae pv. phaseolicola (HrpZPsph). The HrpZ protein was expressed as an N-terminal fusion to the PR1 signal peptide (SP/HrpZ) to direct harpin accumulation to the plant apoplast. Transgene integration was verified by mPCR in all primary transformants (T0), while immunoblot analysis confirmed that the protein HrpZPsph was produced and the signal peptide was properly processed. Neither T0 plants nor selfed progeny (T1) showed macroscopically visible necrosis or any other macroscopic phenotypes. However, plants expressing the SP/HrpZPsph showed increased vigor and grew faster in comparison with non-transgenic control plants. Transgenic resistance was assessed after challenge inoculation with BNYVV on T1 progeny by scoring of disease symptoms and by DAS-ELISA at 20 and 30 dpi. Transgenic and control lines showed significant differences in terms of the number of plants that became infected, the timing of infection and the disease symptoms displayed. Plants expressing the SP/HrpZPsph developed localized leaf necrosis in the infection area and had enhanced resistance upon challenge with BNYVV. In order to evaluate the SP/HrpZ-based resistance in the sugar beet host, A. rhizogenes-mediated root transformation was exploited as a transgene expression platform. Upon BNYVV inoculation, transgenic sugar beet hairy roots showed high level of BNYVV resistance. In contrast, the aerial non-transgenic parts of the same seedlings had virus titers that were comparable to those of the seedlings that were untransformed or transformed with wild type R1000 cells. These findings indicate that the transgenically expressed SP/HrpZ protein results in enhanced rhizomania resistance both in a model plant and sugar beet, the natural host of BNYVV. Possible molecular mechanisms underlying the enhanced resistance and plant growth phenotypes observed in SP/HrpZ transgenic plants are discussed. PMID:21394206

The hrpZ gene of Pseudomonas syringae pv. phaseolicola enhances resistance to rhizomania disease in transgenic Nicotiana benthamiana and sugar beet.

PubMed

Pavli, Ourania I; Kelaidi, Georgia I; Tampakaki, Anastasia P; Skaracis, George N

2011-03-04

To explore possible sources of transgenic resistance to the rhizomania-causing Beet necrotic yellow vein virus (BNYVV), Nicotiana benthamiana plants were constructed to express the harpin of Pseudomonas syringae pv. phaseolicola (HrpZ(Psph)). The HrpZ protein was expressed as an N-terminal fusion to the PR1 signal peptide (SP/HrpZ) to direct harpin accumulation to the plant apoplast. Transgene integration was verified by mPCR in all primary transformants (T0), while immunoblot analysis confirmed that the protein HrpZ(Psph) was produced and the signal peptide was properly processed. Neither T0 plants nor selfed progeny (T1) showed macroscopically visible necrosis or any other macroscopic phenotypes. However, plants expressing the SP/HrpZ(Psph) showed increased vigor and grew faster in comparison with non-transgenic control plants. Transgenic resistance was assessed after challenge inoculation with BNYVV on T1 progeny by scoring of disease symptoms and by DAS-ELISA at 20 and 30 dpi. Transgenic and control lines showed significant differences in terms of the number of plants that became infected, the timing of infection and the disease symptoms displayed. Plants expressing the SP/HrpZ(Psph) developed localized leaf necrosis in the infection area and had enhanced resistance upon challenge with BNYVV. In order to evaluate the SP/HrpZ-based resistance in the sugar beet host, A. rhizogenes-mediated root transformation was exploited as a transgene expression platform. Upon BNYVV inoculation, transgenic sugar beet hairy roots showed high level of BNYVV resistance. In contrast, the aerial non-transgenic parts of the same seedlings had virus titers that were comparable to those of the seedlings that were untransformed or transformed with wild type R1000 cells. These findings indicate that the transgenically expressed SP/HrpZ protein results in enhanced rhizomania resistance both in a model plant and sugar beet, the natural host of BNYVV. Possible molecular mechanisms underlying the enhanced resistance and plant growth phenotypes observed in SP/HrpZ transgenic plants are discussed.

Design and optimization of photovoltaics recycling infrastructure.

PubMed

Choi, Jun-Ki; Fthenakis, Vasilis

2010-11-15

With the growing production and installation of photovoltaics (PV) around the world constrained by the limited availability of resources, end-of-life management of PV is becoming very important. A few major PV manufacturers currently are operating several PV recycling technologies at the process level. The management of the total recycling infrastructure, including reverse-logistics planning, is being started in Europe. In this paper, we overview the current status of photovoltaics recycling planning and discuss our mathematic modeling of the economic feasibility and the environmental viability of several PV recycling infrastructure scenarios in Germany; our findings suggest the optimum locations of the anticipated PV take-back centers. Short-term 5-10 year planning for PV manufacturing scraps is the focus of this article. Although we discuss the German situation, we expect the generic model will be applicable to any region, such as the whole of Europe and the United States.

Lossless hybridization between photovoltaic and thermoelectric devices.

PubMed

Park, Kwang-Tae; Shin, Sun-Mi; Tazebay, Abdullah S; Um, Han-Don; Jung, Jin-Young; Jee, Sang-Won; Oh, Min-Wook; Park, Su-Dong; Yoo, Bongyoung; Yu, Choongho; Lee, Jung-Ho

2013-01-01

The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. Achieving lossless coupling makes the power output from the hybrid device equal to the sum of the maximum power outputs produced separately from individual PV and TE devices. TE devices need to have low internal resistances enough to convey photo-generated currents without sacrificing the PV fill factor. Concomitantly, a large number of p-n legs are preferred to drive a high Seebeck voltage in TE. Our simple method of attaching a TE device to a PV device has greatly improved the conversion efficiency and power output of the PV device (~30% at a 15°C temperature gradient across a TE device).

Lossless hybridization between photovoltaic and thermoelectric devices

PubMed Central

Park, Kwang-Tae; Shin, Sun-Mi; Tazebay, Abdullah S.; Um, Han-Don; Jung, Jin-Young; Jee, Sang-Won; Oh, Min-Wook; Park, Su-Dong; Yoo, Bongyoung; Yu, Choongho; Lee, Jung-Ho

2013-01-01

The optimal hybridization of photovoltaic (PV) and thermoelectric (TE) devices has long been considered ideal for the efficient harnessing solar energy. Our hybrid approach uses full spectrum solar energy via lossless coupling between PV and TE devices while collecting waste energy from thermalization and transmission losses from PV devices. Achieving lossless coupling makes the power output from the hybrid device equal to the sum of the maximum power outputs produced separately from individual PV and TE devices. TE devices need to have low internal resistances enough to convey photo-generated currents without sacrificing the PV fill factor. Concomitantly, a large number of p-n legs are preferred to drive a high Seebeck voltage in TE. Our simple method of attaching a TE device to a PV device has greatly improved the conversion efficiency and power output of the PV device (~30% at a 15°C temperature gradient across a TE device). PMID:23820973

PV technology and success of solar electricity in Vietnam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dung, T.Q.

1997-12-31

Since 1990 the PV Technology and the Solar electricity have been strongly developed in Vietnam. The PV experts of Solarlab have studied and set up an appropriate PV Technology responding to local Market needs. It has not only stood well but has been also transferred to Mali Republic and Lao P.D.R. The PV off grid systems of Solarlab demonstrate good efficiency and low prices. Over 60 solar stations and villages have been built to provide solar lighting for about 3000 families along the country in remote, mountainous areas and islands. 400 families are using stand-alone Solar Home Systems. The Solarmore » electricity has been chosen for Rural Electrification and National Telecommunication Network in remote and mountainous regions. Many International projects in cooperation with FONDEM-France, SELF USA and Governmental PV projects have been realized by Solarlab. The experiences of maintenance, management and finance about PV development in Vietnam are also mentioned.« less

Mechanisms of Thrombogenesis in Polycythemia Vera

PubMed Central

Kroll, Michael H.; Michaelis, Laura C.; Verstovsek, Srdan

2015-01-01

Thrombotic and cardiovascular events are among the leading causes of death for patients with polycythemia vera (PV), and thrombosis history is a key criterion for patient risk stratification and treatment strategy. Little is known, however, about mechanisms of thrombogenesis in patients with PV. This report provides an overview of thrombogenesis pathophysiology in patients with PV and elucidates the roles of conventional and nonconventional thrombosis risk factors. In addition to several conventional risk factors for thrombosis, clinical data have implicated increased hematocrit and red blood cell adhesiveness, activated platelets, leukocytosis, and elevated JAK2V617F allele burden in patients with PV. Furthermore, PV-related inflammation may exacerbate thrombogenesis through varied mechanisms, including endothelial damage, inhibition of natural anticoagulant pathways, and secretion of procoagulant factors. These findings suggest a direct link between myeloproliferation and thrombogenesis in PV, which is likely to provide new opportunities for targeted antithrombotic interventions aimed at decreasing PV-related morbidity and mortality. PMID:25577686

The Amelioration of Myelofibrosis with Thrombocytopenia by a JAK1/2 Inhibitor, Ruxolitinib, in a Post-polycythemia Vera Myelofibrosis Patient with a JAK2 Exon 12 Mutation.

PubMed

Ikeda, Kazuhiko; Ueda, Koki; Sano, Takahiro; Ogawa, Kazuei; Ikezoe, Takayuki; Hashimoto, Yuko; Morishita, Soji; Komatsu, Norio; Ohto, Hitoshi; Takeishi, Yasuchika

2017-01-01

Less than 5% of patients with polycythemia vera (PV) show JAK2 exon 12 mutations. Although PV patients with JAK2 exon 12 mutations are known to develop post-PV myelofibrosis (MF) as well as PV with JAK2V617F, the role of JAK inhibitors in post-PV MF patients with JAK2 exon 12 mutations remains unknown. We describe how treatment with a JAK1/2 inhibitor, ruxolitinib, led to the rapid amelioration of marrow fibrosis, erythrocytosis and thrombocytopenia in a 77-year-old man with post-PV MF who carried a JAK2 exon 12 mutation (JAK2H538QK539L). This case suggests that ruxolitinib is a treatment option for post-PV MF in patients with thrombocytopenia or JAK2 exon 12 mutations.

Novel laboratory mouse papillomavirus (MusPV) infection.

PubMed

Ingle, A; Ghim, S; Joh, J; Chepkoech, I; Bennett Jenson, A; Sundberg, J P

2011-03-01

Most papillomaviruses (PVs) are oncogenic. There are at least 100 different human PVs and 65 nonhuman vertebrate hosts, including wild rodents, which have species-specific PV infections. Florid papillomatosis arose in a colony of NMRI-Foxn1(nu)/Foxn1(nu) (nude) mice at the Advanced Centre for Treatment Research and Education in Cancer in India. Lesions appeared at the mucocutaneous junctions of the nose and mouth. Histologically, lesions were classical papillomas with epidermal hyperplasia on thin fibrovascular stalks in a verrucous pattern. Koilocytotic cells were observed in the stratum granulosum of the papillomatous lesions. Immunohistochemically, these abnormal cells were positive for PV group-specific antigens. With transmission electron microscopy, virus particles were observed in crystalline intranuclear inclusions within keratinocytes. The presence of a mouse PV, designated MusPV, was confirmed by amplification of PV DNA with degenerative primers specific for PVs. This report is the first of a PV and its related disease in laboratory mice.

New Analysis Finds Synergistic Relationship Between High PV Penetration and

Science.gov Websites

High PV Penetration and Energy Storage Deployment April 10, 2018 Adding higher penetrations of solar High PV Penetration and Energy Storage Deployment New Analysis Finds Synergistic Relationship Between photovoltaics (PV) to the electric power grid could increase the potential for energy storage to meet peak

Dirk Jordan | NREL

Science.gov Websites

quantify module degradation rates. Statistical analysis of reported degradation rates of PV modules degradation rates," Prog. in PV 24(7), 2016, DOI: 10.1002/pip.2744 Jordan D.C., Silverman T.J PV, 2017, DOI: 10.1002/pip.2866 Jordan D.C., Silverman T.J., Sekulic B., Kurtz S.R., "PV

Breakthrough: micro-electronic photovoltaics

ScienceCinema

Okandan, Murat; Gupta, Vipin

2018-01-16

Sandia developed tiny glitter-sized photovoltaic (PV) cells that could revolutionize solar energy collection. The crystalline silicon micro-PV cells will be cheaper and have greater efficiencies than current PV collectors. Micro-PV cells require relatively little material to form well-controlled, highly efficient devices. Cell fabrication uses common microelectric and micro-electromechanical systems (MEMS) techniques.

Beacons In Brief. P/PV In Brief. Issue 2

ERIC Educational Resources Information Center

Blank, Susan; Farley, Chelsea

2004-01-01

This second issue in P/PV's "In Brief" series focuses on the San Francisco Beacon Initiative and P/PV's recently released evaluation results. The Beacon Initiative established after-school programs in eight public schools in low-income San Francisco neighborhoods. P/PV's 36-month evaluation examined key developmental and academic outcomes.…

Photovoltaic Module Reliability Workshop 2012: February 28 - March 1, 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurtz, S.

2013-11-01

NREL's Photovoltaic (PV) Module Reliability Workshop (PVMRW) brings together PV reliability experts to share information, leading to the improvement of PV module reliability. Such improvement reduces the cost of solar electricity and promotes investor confidence in the technology--both critical goals for moving PV technologies deeper into the electricity marketplace.

Design and simulation of maximum power point tracking (MPPT) system on solar module system using constant voltage (CV) method

NASA Astrophysics Data System (ADS)

Bhatara, Sevty Satria; Iskandar, Reza Fauzi; Kirom, M. Ramdlan

2016-02-01

Solar energy is one of renewable energy resource where needs a photovoltaic module to convert it into electrical energy. One of the problems on solar energy conversion is the process of battery charging. To improve efficiency of energy conversion, PV system needs another control method on battery charging called maximum power point tracking (MPPT). This paper report the study on charging optimation using constant voltage (CV) method. This method has a function of determining output voltage of the PV system on maximal condition, so PV system will always produce a maximal energy. A model represented a PV system with and without MPPT was developed using Simulink. PV system simulation showed a different outcome energy when different solar radiation and numbers of solar module were applied in the model. On the simulation of solar radiation 1000 W/m2, PV system with MPPT produces 252.66 Watt energy and PV system without MPPT produces 252.66 Watt energy. The larger the solar radiation, the greater the energy of PV modules was produced.

U.S. Residential Photovoltaic (PV) System Prices, Q4 2013 Benchmarks: Cash Purchase, Fair Market Value, and Prepaid Lease Transaction Prices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davidson, C.; James, T. L.; Margolis, R.

The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% declinemore » from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.« less

Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

DOE PAGES

Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

2015-06-23

Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

MATLAB Simulation of Photovoltaic and Photovoltaic/Thermal Systems Performance

NASA Astrophysics Data System (ADS)

Nasir, Farah H. M.; Husaini, Yusnira

2018-03-01

The efficiency of the photovoltaic reduces when the photovoltaic cell temperature increased due to solar irradiance. One solution is come up with the cooling system photovoltaic system. This combination is forming the photovoltaic-thermal (PV/T) system. Not only will it generate electricity also heat at the same time. The aim of this research is to focus on the modeling and simulation of photovoltaic (PV) and photovoltaic-thermal (PV/T) electrical performance by using single-diode equivalent circuit model. Both PV and PV/T models are developed in Matlab/Simulink. By providing the cooling system in PV/T, the efficiency of the system can be increased by decreasing the PV cell temperature. The maximum thermal, electrical and total efficiency values of PV/T in the present research are 35.18%, 15.56% and 50.74% at solar irradiance of 400 W/m2, mass flow rate of 0.05kgs-1 and inlet temperature of 25 °C respectively has been obtained. The photovoltaic-thermal shows that the higher efficiency performance compared to the photovoltaic system.

Overview of the Photovoltaic Manufacturing Technology (PVMaT) project

NASA Astrophysics Data System (ADS)

Witt, C. E.; Mitchell, R. L.; Mooney, G. D.

1993-08-01

The Photovoltaic Manufacturing Technology (PVMaT) project is a historic government/industry photovoltaic (PV) manufacturing R&D partnership composed of joint efforts between the federal government (through the US Department of Energy) and members of the US PV industry. The project's ultimate goal is to ensure that the US industry retains and extends its world leadership role in the manufacture and commercial development of PV components and systems. PVMaT is designed to do this by helping the US PV industry improve manufacturing processes, accelerate manufacturing cost reductions for PV modules, improve commercial product performance, and lay the groundwork for a substantial scale-up of US-based PV manufacturing capacities. Phase 1 of the project, the problem identification phase, was completed in early 1991. Phase 2, the problem solution phase, which addresses process-specific problems of specific manufacturers, is now underway with an expected duration of 5 years. Phase 3 addresses R&D problems that are relatively common to a number of PV companies or the PV industry as a whole. These 'generic' problem areas are being addressed through a teamed research approach.

Photovoltaic battery & charge controller market & applications survey. An evaluation of the photovoltaic system market for 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammond, R.L.; Turpin, J.F.; Corey, G.P.

1996-12-01

Under the sponsorship of the Department of Energy, Office of Utility Technologies, the Battery Analysis and Evaluation Department and the Photovoltaic System Assistance Center of Sandia National Laboratories (SNL) initiated a U.S. industry-wide PV Energy Storage System Survey. Arizona State University (ASU) was contracted by SNL in June 1995 to conduct the survey. The survey included three separate segments tailored to: (a) PV system integrators, (b) battery manufacturers, and (c) PV charge controller manufacturers. The overall purpose of the survey was to: (a) quantify the market for batteries shipped with (or for) PV systems in 1995, (b) quantify the PVmore » market segments by battery type and application for PV batteries, (c) characterize and quantify the charge controllers used in PV systems, (d) characterize the operating environment for energy storage components in PV systems, and (e) estimate the PV battery market for the year 2000. All three segments of the survey were mailed in January 1996. This report discusses the purpose, methodology, results, and conclusions of the survey.« less

Analysis of typical world countries' wind power and PV industry policies and their enlightenment to China

NASA Astrophysics Data System (ADS)

Zeng, Ming; Yang, Lijun; Qiu, Hongji; Li, Yuanfei; Peng, Lilin

2017-01-01

The wind power and PV are the key fields of clean energy development in China in recent years. However, there are still many aspects of problems in wind power and PV industries at present, such as the insufficient consumptive ability and the limitation of market competition capability. The effective leading and support of government in the aspect of policies is especially needed in order to solve these problems. Based on the analysis of main policies system of wind power and PV in our country, Spain, the United Kingdom and Germany are chosen as typical countries because of their wind power and PV industries are relatively developed. Their policies of wind power and PV industries are studied respectively from five aspects, namely macroscopic laws, development planning, administrative policies, fiscal and tax policies and price policies. Then the comparison among typical countries and China is made and the exiting problems in China's policies of wind power and PV industries are summed up. Finally, the suggestions to promote China's wind power and PV industries development are presented.

Simulation and Experimental Study on Effect of Phase Change Material Thickness to Reduce Temperature of Photovoltaic Panel

NASA Astrophysics Data System (ADS)

Indartono, Y. S.; Prakoso, S. D.; Suwono, A.; Zaini, I. N.; Fernaldi, B.

2015-09-01

Solar energy is promising renewable energy which can be applied in Indonesia. Average solar radiation in the country is 4.8 kWh/day/m2. Weakness of silicon-based photovoltaic (PV) is efficiency reduction caused by temperature increase. Many attempts have been done to reduce PV temperature. In previous study, palm oil, which is widely available in Indonesia, is suitable to be used as phase change material (PCM) to reduce PV temperature. In this study, thickness of aluminium rectangular-tube containing phase change material oil is varied. The tube is placed at back part of PV. Numerical and experimental study was done to evaluate the effect of tube thickness to the temperature reduction of the PV. Variation of tube thickness used in the experiment is 50.8mm, 76.2 mm, 101.6 mm. Both studies show that increase of PCM thickness reduces PV temperature. Higher PCM thickness cause large reduction on PV temperature. Simulation result shows there is an optimum thickness of the PCM which is applied to the PV.

Performance test of a grid-tied PV system to power a split air conditioner system in Surabaya

NASA Astrophysics Data System (ADS)

Tarigan, E.

2017-11-01

Air conditioner for cooling air is one of the major needs for those who live in hot climate area such as Indonesia. This work presents the performance test of a grid-tied PV system to power air conditioner under a hot tropical climate in Surabaya, Indonesia. A 800 WP grid-tied photovoltaic (PV) system was used, and its performance was tested to power a 0.5 pk of split air conditioner system. It was found that about 3.5 kWh daily energy was consumed by the tested air conditioner system, and about 80% it could be supplied from the PV system. While the other 20% was supplied by the grid during periods of low solar irradiation, 440 Wh of energy was fed into the grid during operation out of office hours. By using the grid-tied PV system, the energy production by PV system did not need to match the consumption of the air conditioner. However, a larger capacity of PV system would mean that a higher percentage of the load would be covered by PV system.

Desulfurization of 4-methyl dibenzothiophene using titanium supported Keggin type polyoxometalate

NASA Astrophysics Data System (ADS)

Lesbani, Aldes; Anggraini, Ana; Mohadi, Risfidian; Rohendi, Dedi; Said, Muhammad

2017-03-01

Titanium supported Keggin type polyoxometalate H5PV2Mo10O40.nH2O has been prepared using tetra isopropyl orthotitanate by sol-gel method and microemulsion to form H5PV2Mo10O40/TiO2. Compound H5PV2Mo10O40.nH2O/TiO2 was characterized using FTTR spectroscopy, X-Ray analysis, and acidity measurement. FTTR spectrum showed that all vibration of titanium and polyoxometalate were appeared in H5PV2Mo10O40.nH2O/TiO2 with decreasing crystallinity. The acidity of H5PV2Mo10O40.nH2O/TiO2 was higher than H5PV2Mo10O40.nH2O. Desulfurization of 4-methyl dibenzothiophene (4-MDBT) using H5PV2Mo10O40.nH2O/TiO2 as catalyst resulted conversion of 4-MDBT was 99% and higher than desulfurization using H5PV2Mo10O40.nH2O under mild conditions.

Performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX

NASA Astrophysics Data System (ADS)

Syafiqah, Z.; Amin, N. A. M.; Irwan, Y. M.; Irwanto, M.; Leow, W. Z.; Amelia, A. R.

2017-09-01

A research has been conducted to find the optimum combination for DC fan air cooling system of photovoltaic (PV) panel. During normal operation of PV panel, it is estimated that only 15 % of solar radiation is converted into electrical energy. Meanwhile, the rest of the solar radiation is converted into heat energy which affects the performance of the PV panel. Therefore, the aim of this research is to investigate the performance power evaluation of DC fan cooling system for PV panel by using ANSYS CFX. The effect of airflow configuration of DC fan has been investigated. This is to analyze whether the airflow circulation of DC fan cause a change towards the maximum temperature of PV panel. Besides, the impact of varying number of DC fans attached at the back of PV panel is evaluated. The result of airflow circulation of DC fan has been discussed. Meanwhile, with the increment number of DC fans, the PV panel temperature drops significantly. As a conclusion, the optimum number of DC fans is two with the combination of inlet airflow.

Solar PV O&M Standards and Best Practices – Existing Gaps and Improvement Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

2014-11-01

As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PVmore » systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.« less

Performance degradation of photovoltaic modules at different sites

NASA Astrophysics Data System (ADS)

Arab, A. Hadj; Mahammed, I. Hadj; Ould Amrouche, S.; Taghezouit, B.; Yassaa, N.

2018-05-01

In this work are presented results of electrical performance measurements of 120 crystalline silicon PV modules following long-term outdoor measurements. A set of 90 PV modules represent the first grid-connected photovoltaic (PV) system in Algeria, installed at the level of the “Centre de Développement des Energies Renouvelables” (CDER) site (Mediterranean coast), Bouzareah. The other 30 PV modules were undertaken in an arid area of the desert region of Ghardaïa site, about 600 km south of Algiers, with measurements collected from different applications. Following different characterization tests, we noticed that the all tested PV modules kept their power-generating rate except a slight reduction. Therefore, a mathematical model has been used to carry out PV module testing at different irradiance and temperature levels. Hence, different PV module parameters have been calculated from the recorded values of the open-circuit voltage, the short-circuit current, the voltage and current at maximum power point. The electrical measurements have indicated different degradations of current-voltage parameters. All the PV modules stated a decrease in the nominal power, which is variable from one module to another.

Solar PV O&M Standards and Best Practices - Existing Gaps and Improvement Efforts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

2014-11-01

As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PVmore » systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.« less

Photovoltaic Hosting Capacity of Feeders with Reactive Power Control and Tap Changers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ceylan, Oğuzhan; Paudyal, Sumit; Bhattarai, Bishnu P.

This paper proposes an algorithm to determine photovoltaic (PV) hosting capacity of power distribution networks as a function of number of PV injection nodes, reactive power support from the PVs, and the sub-station load tap changers (LTCs). In the proposed method, several minute by minute simulations are run based on randomly chosen PV injection nodes, daily PV output profiles, and daily load profiles from a pool of high-resolution realistic data set. The simulation setup is built using OpenDSS and MATLAB. The performance of the proposed method is investigated in the IEEE 123-node distribution feeder for multiple scenarios. The case studiesmore » are performed particularly for one, two, five and ten PV injection nodes, and looking at the maximum voltage deviations. Case studies show that the PV hosting capacity of the 123-node feeder greatly differs with the number of PV injection nodes. We have also observed that the PV hosting capacity increases with reactive power support and higher tap position of sub-station LTC.« less

Capacity of wild-type and chemokine-armed parvovirus H-1PV for inhibiting neo-angiogenesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lavie, Muriel; Struyf, Sofie; Stroh-Dege, Alexandra

2013-12-15

Anti-angiogenic therapy has been recognized as a powerful potential strategy for impeding the growth of various tumors. However no major therapeutic effects have been observed to date, mainly because of the emergence of several resistance mechanisms. Among novel strategies to target tumor vasculature, some oncolytic viruses open up new prospects. In this context, we addressed the question whether the rodent parvovirus H-1PV can target endothelial cells. We show that cultures of human normal (HUVEC) and immortalized (KS-IMM) endothelial cells sustain an abortive viral cycle upon infection with H-1PV and are sensitive to H-1PV cytotoxicity. H-1PV significantly inhibits infected KS-IMM tumormore » growth. This effect may be traced back by the virus ability to both kill proliferating endothelial cells and inhibit VEGF production Recombinant H-1PV vectors can also transduce tumor cells with chemokines endowed with anti-angiogenesis properties, and warrant further validation for the treatment of highly vascularized tumors. - Highlights: • The oncolytic parvovirus H-1PV can target endothelial cells. • Abortive viral cycle upon infection of endothelial cells with H-1PV. • Inhibition of VEGF expression and KS-IMM tumor growth by H-1PV.« less

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

DOE PAGES

Marion, Bill; Smith, Benjamin

2017-03-27

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

Integrating Solar into Florida's Power System: Potential Roles for Flexibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hale, Elaine T; Stoll, Brady; Novacheck, Joshua E

Although Florida has very little photovoltaic (PV) generation to date, it is reasonable to expect significant deployment in the 2020s under a variety of future policy and cost scenarios. To understand these potential futures, we model Florida Reliability Coordinating Council operations in 2026 over a wide range of PV penetrations with various combinations of battery storage capacity, demand response, and increased operational flexibility. By calculating the value of PV under a wide range of conditions, we find that at least 5%, and more likely 10-24%, PV penetration is cost competitive in Florida within the next decade with baseline flexibility andmore » all but the most pessimistic of assumptions. For high PV penetrations, we demonstrate Florida's electrical net-load variability (duck curve) challenges, the associated reduction of PV's value to the system, and the ability of flexibility options-in particular energy-shifting resources-to preserve value and increase the economic carrying capacity of PV. A high level of demand response boosts the economic carrying capacity of PV by up to 0.5-2 percentage points, which is comparable to the impact of deploying 1 GW of battery storage. Adding 4 GW of battery storage expands the economic carrying capacity of PV by up to 6 percentage points.« less

PV integration into a CSP plant

NASA Astrophysics Data System (ADS)

Carvajal, Javier López; Barea, Jose M.; Barragan, Jose; Ortega, Carlos

2017-06-01

This paper describes a preliminary techno-economic analysis of the integration of a PV plant into an optimized Parabolic Trough Plant in order to reduce the online consumptions and thus, increase the net electricity injected into the grid. The idea is to assess the feasibility of such project and see what configuration would be the optimal. An extra effort has been made in terms of modelling as the analysis has to be done to the integrated CSP + PV plant instead of analyzing them independently. Two different technologies have been considered for the PV plant, fix and one-axis tracking. Additionally three different scenarios have been considered for the CSP plant auxiliary consumptions as they are essential for determining the optimal PV plant (the higher the auxiliary consumption the higher the optimal PV plant). As could be expected, the results for all cases with PV show an improvement in terms of electricity generation and also in terms of LCOE with respect to the CSP plant. Such improvement is slightly higher with tracking technology for this specific study. Although this exercise has been done to an already designed CSP plant (so only the PV plant had to be optimized), the methodology could be applied for the optimization of an integrated CSP + PV plant during the design phase.

Photovoltaic system derived data for determining the solar resource and for modeling the performance of other photovoltaic systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marion, Bill; Smith, Benjamin

Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. Here, a method was developed to back-solve for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the measured ac power of south-facing PV module/micro-inverter systems. The method was validated using one year of irradiance and PV performance measurements for five PV systems, each with a different tilt/azimuth orientation, and located in Golden, Colorado. Compared to using a measured global horizontal irradiance for PV performance model input,more » using the back-solved values of DNI and DHI only increased the range of mean bias deviations from measured values by 0.6% for the modeled annual averages of the global tilt irradiance and ac power for the five PV systems. Correcting for angle-of-incidence effects is an important feature of the method to prevent underestimating the solar resource and for modeling the performance of PV systems with more dissimilar PV module orientations. The results for the method were also shown more favorable than the results when using an existing power projection method for estimating the ac power.« less

A fault diagnosis system for PV power station based on global partitioned gradually approximation method

NASA Astrophysics Data System (ADS)

Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

2016-08-01

As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

Solar San Diego: The Impact of Binomial Rate Structures on Real PV Systems; Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanGeet, O.; Brown, E.; Blair, T.

2008-05-01

There is confusion in the marketplace regarding the impact of solar photovoltaics (PV) on the user's actual electricity bill under California Net Energy Metering, particularly with binomial tariffs (those that include both demand and energy charges) and time-of-use (TOU) rate structures. The City of San Diego has extensive real-time electrical metering on most of its buildings and PV systems, with interval data for overall consumption and PV electrical production available for multiple years. This paper uses 2007 PV-system data from two city facilities to illustrate the impacts of binomial rate designs. The analysis will determine the energy and demand savingsmore » that the PV systems are achieving relative to the absence of systems. A financial analysis of PV-system performance under various rate structures is presented. The data revealed that actual demand and energy use benefits of binomial tariffs increase in summer months, when solar resources allow for maximized electricity production. In a binomial tariff system, varying on- and semi-peak times can result in approximately $1,100 change in demand charges per month over not having a PV system in place, an approximate 30% cost savings. The PV systems are also shown to have a 30%-50% reduction in facility energy charges in 2007.« less

Felis catus papillomavirus type-2 but not type-1 is detectable and transcriptionally active in the blood of healthy cats.

PubMed

Altamura, G; Jebara, G; Cardeti, G; Borzacchiello, G

2018-04-01

Papillomaviruses (PVs) are small DNA viruses that induce benign and/or malignant epithelial tumours in different species, including the domestic cat (Felis catus). To date, five F. catus papillomavirus genotypes have been identified (FcaPV-1 to FcaPV-5). FcaPV-1 is associated with skin and oral benign lesions, while FcaPV-2 infection is widely associated with feline squamous cell carcinomas. Several human and animal PVs have been found in body fluids such as peripheral blood; however, the presence of FcaPVs in non-epithelial tissues has not previously been investigated. The aim of this study was to assess the presence and gene expression of FcaPV-1 and FcaPV-2 in the blood of healthy cats. We detected FcaPV-2 DNA in 26 of 103 (25%) blood samples. Importantly, FcaPV-2 L1, E2, E6 and E7 genes were found to be expressed in 3 (25%), 11 (92%), 6 (50%) and 5 (42%) of the samples available for mRNA analysis, respectively. FcaPV-1 was not detected in any of the blood samples analysed here. The data obtained in this work suggest active and eventually productive infection of FcaPV-2 in the blood of healthy cats, implying a possible role in intra-individual spreading as well as in vertical and horizontal transmission. © 2017 Blackwell Verlag GmbH.

Pathology, Organ Distribution, and Immune Response after Single and Repeated Intravenous Injection of Rats with Clinical-Grade Parvovirus H1

PubMed Central

Geletneky, Karsten; Leoni, Anne-Laure; Pohlmeyer-Esch, Gabriele; Loebhard, Stephanie; Baetz, Andrea; Leuchs, Barbara; Roscher, Mandy; Hoefer, Constance; Jochims, Karin; Dahm, Michael; Huber, Bernard; Rommelaere, Jean; Krebs, Ottheinz; Hajda, Jacek

2015-01-01

Parvovirus H1 (H1PV) is an autonomous parvovirus that is transmitted in rodent populations. Its natural host is rats. H1PV infection is nonpathogenic except in rat and hamster fetuses and newborns. H1PV infection of human cancer cells caused strong oncolytic effects in preclinical models. For a clinical trial of H1PV in patients with brain tumors, clinical-grade H1PV was produced according to Good Manufacturing Practices. This report focuses on results obtained after a single high-dose intravenous injection of highly purified H1PV in 30 rats and multiple (n = 17) intravenous injections at 3 dose levels in 223 rats. In both studies, no virus-related mortality or macroscopic organ changes related to H1PV occurred. Histopathology after multiple virus injections revealed minimal diffuse bile duct hyperplasia in livers of animals of the highest dose group and germinal center development in spleens of animals from the high-dose group. Liver changes were reversible within a 2-wk recovery period after the last injection. Hematology, blood chemistry, and coagulation analyses did not reveal significant toxicologic changes due to H1PV. Virus injection stimulated the production of IgG antibodies but did not alter mononuclear cell function or induce cytokine release. PCR analysis showed dose-dependent levels of viral genomes in all organs tested. The virus was excreted primarily through feces. These data provide important information regarding H1PV infection in its natural host. Due to the confirmation of the favorable safety profile of H1PV in a permissive animal model, a phase I/IIa clinical trial of H1PV in brain tumor patients could be initiated. PMID:25730754

Space Environment Testing of Photovoltaic Array Systems at NASA's Marshall Space Flight Center

NASA Technical Reports Server (NTRS)

Phillips, Brandon S.; Schneider, Todd A.; Vaughn, Jason A.; Wright, Kenneth H., Jr.

2015-01-01

To successfully operate a photovoltaic (PV) array system in space requires planning and testing to account for the effects of the space environment. It is critical to understand space environment interactions not only on the PV components, but also the array substrate materials, wiring harnesses, connectors, and protection circuitry (e.g. blocking diodes). Key elements of the space environment which must be accounted for in a PV system design include: Solar Photon Radiation, Charged Particle Radiation, Plasma, and Thermal Cycling. While solar photon radiation is central to generating power in PV systems, the complete spectrum includes short wavelength ultraviolet components, which photo-ionize materials, as well as long wavelength infrared which heat materials. High energy electron radiation has been demonstrated to significantly reduce the output power of III-V type PV cells; and proton radiation damages material surfaces - often impacting coverglasses and antireflective coatings. Plasma environments influence electrostatic charging of PV array materials, and must be understood to ensure that long duration arcs do not form and potentially destroy PV cells. Thermal cycling impacts all components on a PV array by inducing stresses due to thermal expansion and contraction. Given such demanding environments, and the complexity of structures and materials that form a PV array system, mission success can only be ensured through realistic testing in the laboratory. NASA's Marshall Space Flight Center has developed a broad space environment test capability to allow PV array designers and manufacturers to verify their system's integrity and avoid costly on-orbit failures. The Marshall Space Flight Center test capabilities are available to government, commercial, and university customers. Test solutions are tailored to meet the customer's needs, and can include performance assessments, such as flash testing in the case of PV cells.

Mechanism of action and in vitro activity of short hybrid antimicrobial peptide PV3 against Pseudomonas aeruginosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Memariani, Hamed; Shahbazzadeh, Delavar; Sabatier, Jean-Marc

Antimicrobial peptides are attractive candidates for developing novel therapeutic agents, since they are lethal to a broad spectrum of pathogens and have a unique low tendency for resistance development. In this study, mechanism of action and in vitro anti-pseudomonal activity of previously designed short hybrid antimicrobial peptide PV3 were investigated. Compared to ceftazidime, PV3 had not only higher antibacterial activity but also faster bactericidal activity. PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. Although the antimicrobial activity of PV3 was reduced in Mueller-Hinton broth (MHB) containing human serum, it was still active enough to eradicationmore » of bacteria at low concentrations. Compared with standard condition (MHB only), there was no significant decrease in antibacterial activity of PV3 against P. aeruginosa strains under 150 mM NaCl (p = 0.615) and 1 mM MgCl{sub 2} (p = 0.3466). Fluorescence microscopy and field emission scanning electron microscopy further indicated that PV3 killed bacteria by disrupting the cell membrane. Since PV3 has potent anti-pseudomonal activity and has little cytotoxicity in vitro, it seems plausible that the peptide should be further investigated with animal studies to support future pharmacological formulations and potential topical applications. - Highlights: • PV3 killed Pseudomonas aeruginosa by membrane-disrupting mechanism. • PV3 reduced biofilm biomass and viability of biofilm embedded bacteria in a concentration-dependent manner. • Short hybrid antimicrobial peptide PV3 exhibited higher and faster bactericidal activity comparing to ceftazidime.« less

ENVI-PV: An Interactive Web Client for Multi-Criteria Life Cycle Assessment of Photovoltaic Systems Worldwide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perez-Lopez, Paula; Gschwind, Benoit; Blanc, Philippe

Solar photovoltaics (PV) is the second largest source of new capacity among renewable energies. The worldwide capacity encompassed 135 GW in 2013 and is estimated to increase to 1721 GW in 2030 and 4674 GW in 2050, according to a prospective high-renewable scenario. To achieve this production level while minimizing environmental impacts, decision makers must have access to environmental performance data that reflect their high spatial variability accurately. We propose ENVI-PV (http://viewer.webservice-energy.org/project_iea), a new interactive tool that provides maps and screening level data, based on weighted average supply chains, for the environmental performance of common PV technologies. Environmental impacts ofmore » PV systems are evaluated according to a life cycle assessment approach. ENVI-PV was developed using a state-of-the-art interoperable and open standard Web Service framework from the Open Geospatial Consortium (OGC). It combines the latest life cycle inventories, published in 2015 by the International Energy Agency (IEA) under the Photovoltaic Power Systems Program (PVPS) Task 12, and some inventories previously published from Ecoinvent v2.2 database with solar irradiation estimates computed from the worldwide NASA SSE database. ENVI-PV is the first tool to propose a worldwide coverage of environmental performance of PV systems using a multi-criteria assessment. The user can compare the PV environmental performance to the environmental footprint of country electricity mixes. ENVI-PV is designed as an environmental interactive tool to generate PV technological options and evaluate their performance in different spatial and techno-economic contexts. Its potential applications are illustrated in this paper with several examples.« less

Prostate health index (PHI) and prostate-specific antigen (PSA) predictive models for prostate cancer in the Chinese population and the role of digital rectal examination-estimated prostate volume.

PubMed

Chiu, Peter K F; Roobol, Monique J; Teoh, Jeremy Y; Lee, Wai-Man; Yip, Siu-Ying; Hou, See-Ming; Bangma, Chris H; Ng, Chi-Fai

2016-10-01

To investigate PSA- and PHI (prostate health index)-based models for prediction of prostate cancer (PCa) and the feasibility of using DRE-estimated prostate volume (DRE-PV) in the models. This study included 569 Chinese men with PSA 4-10 ng/mL and non-suspicious DRE with transrectal ultrasound (TRUS) 10-core prostate biopsies performed between April 2008 and July 2015. DRE-PV was estimated using 3 pre-defined classes: 25, 40, or 60 ml. The performance of PSA-based and PHI-based predictive models including age, DRE-PV, and TRUS prostate volume (TRUS-PV) was analyzed using logistic regression and area under the receiver operating curves (AUC), in both the whole cohort and the screening age group of 55-75. PCa and high-grade PCa (HGPCa) was diagnosed in 10.9 % (62/569) and 2.8 % (16/569) men, respectively. The performance of DRE-PV-based models was similar to TRUS-PV-based models. In the age group 55-75, the AUCs for PCa of PSA alone, PSA with DRE-PV and age, PHI alone, PHI with DRE-PV and age, and PHI with TRUS-PV and age were 0.54, 0.71, 0.76, 0.78, and 0.78, respectively. The corresponding AUCs for HGPCa were higher (0.60, 0.70, 0.85, 0.83, and 0.83). At 10 and 20 % risk threshold for PCa, 38.4 and 55.4 % biopsies could be avoided in the PHI-based model, respectively. PHI had better performance over PSA-based models and could reduce unnecessary biopsies. A DRE-assessed PV can replace TRUS-assessed PV in multivariate prediction models to facilitate clinical use.

Numerical modeling of uncertainty and variability in the technology, manufacturing, and economics of crystalline silicon photovoltaics

NASA Astrophysics Data System (ADS)

Ristow, Alan H.

2008-10-01

Electricity generated from photovoltaics (PV) promises to satisfy the world's ever-growing thirst for energy without significant pollution and greenhouse gas emissions. At present, however, PV is several times too expensive to compete economically with conventional sources of electricity delivered via the power grid. To ensure long-term success, must achieve cost parity with electricity generated by conventional sources of electricity. This requires detailed understanding of the relationship between technology and economics as it pertains to PV devices and systems. The research tasks of this thesis focus on developing and using four types of models in concert to develop a complete picture of how solar cell technology and design choices affect the quantity and cost of energy produced by PV systems. It is shown in this thesis that high-efficiency solar cells can leverage balance-of-systems (BOS) costs to gain an economic advantage over solar cells with low efficiencies. This advantage is quantified and dubbed the "efficiency premium." Solar cell device models are linked to models of manufacturing cost and PV system performance to estimate both PV system cost and performance. These, in turn, are linked to a model of levelized electricity cost to estimate the per-kilowatt-hour cost of electricity produced by the PV system. A numerical PV module manufacturing cost model is developed to facilitate this analysis. The models and methods developed in this thesis are used to propose a roadmap to high-efficiency multicrystalline-silicon PV modules that achieve cost parity with electricity from the grid. The impact of PV system failures on the cost of electricity is also investigated; from this, a methodology is proposed for improving the reliability of PV inverters.

Characterization of human monoclonal antibodies that neutralize multiple poliovirus serotypes.

PubMed

Puligedda, Rama Devudu; Kouiavskaia, Diana; Al-Saleem, Fetweh H; Kattala, Chandana Devi; Nabi, Usman; Yaqoob, Hamid; Bhagavathula, V Sandeep; Sharma, Rashmi; Chumakov, Konstantin; Dessain, Scott K

2017-10-04

Following the eradication of wild poliovirus (PV), achieving and maintaining a polio-free status will require eliminating potentially pathogenic PV strains derived from the oral attenuated vaccine. For this purpose, a combination of non-cross-resistant drugs, such as small molecules and neutralizing monoclonal antibodies (mAbs), may be ideal. We previously isolated chimpanzee and human mAbs capable of neutralizing multiple PV types (cross-neutralization). Here, we describe three additional human mAbs that neutralize types 1 and 2 PV and one mAb that neutralizes all three types. Most bind conformational epitopes and have unusually long heavy chain complementarity determining 3 domains (HC CDR3). We assessed the ability of the mAbs to neutralize A12 escape mutant PV strains, and found that the neutralizing activities of the mAbs were disrupted by different amino acid substitutions. Competitive binding studies further suggested that the specific mAb:PV interactions that enable cross-neutralization differ among mAbs and serotypes. All of the cloned mAbs bind PV in the vicinity of the "canyon", a circular depression around the 5-fold axis of symmetry through which PV recognizes its cellular receptor. We were unable to generate escape mutants to two of the mAbs, suggesting that their epitopes are important for the PV life cycle. These data indicate that PV cross-neutralization involves binding to highly conserved structures within the canyon that binds to the cellular receptor. These may be facilitated by the long HC CDR3 domains, which may adopt alternative binding configurations. We propose that the human and chimpanzee mAbs described here could have potential as anti-PV therapeutics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interband Cascade Photovoltaic Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Rui Q.; Santos, Michael B.; Johnson, Matthew B.

2014-09-24

In this project, we are performing basic and applied research to systematically investigate our newly proposed interband cascade (IC) photovoltaic (PV) cells [1]. These cells follow from the great success of infrared IC lasers [2-3] that pioneered the use of quantum-engineered IC structures. This quantum-engineered approach will enable PV cells to efficiently convert infrared radiation from the sun or other heat source, to electricity. Such cells will have important applications for more efficient use of solar energy, waste-heat recovery, and power beaming in combination with mid-infrared lasers. The objectives of our investigations are to: achieve extensive understanding of the fundamentalmore » aspects of the proposed PV structures, develop the necessary knowledge for making such IC PV cells, and demonstrate prototype working PV cells. This research will focus on IC PV structures and their segments for utilizing infrared radiation with wavelengths from 2 to 5 μm, a range well suited for emission by heat sources (1,000-2,000 K) that are widely available from combustion systems. The long-term goal of this project is to push PV technology to longer wavelengths, allowing for relatively low-temperature thermal sources. Our investigations address material quality, electrical and optical properties, and their interplay for the different regions of an IC PV structure. The tasks involve: design, modeling and optimization of IC PV structures, molecular beam epitaxial growth of PV structures and relevant segments, material characterization, prototype device fabrication and testing. At the end of this program, we expect to generate new cutting-edge knowledge in the design and understanding of quantum-engineered semiconductor structures, and demonstrate the concepts for IC PV devices with high conversion efficiencies.« less

Bean Metal-Responsive Element-Binding Transcription Factor Confers Cadmium Resistance in Tobacco1

PubMed Central

Sun, Na; Liu, Meng; Zhang, Wentao; Yang, Wanning; Bei, Xiujuan; Ma, Hui; Qiao, Fan; Qi, Xiaoting

2015-01-01

Cadmium (Cd) is highly toxic to plants. Modulation of Cd-responsive transcription is an important way for Cd detoxification in plants. Metal-responsive element (MRE) is originally described in animal metallothionein genes. Although functional MREs also exist in Cd-regulated plant genes, specific transcription factors that bind MRE to regulate Cd tolerance have not been identified. Previously, we showed that Cd-inducible bean (Phaseolus vulgaris) stress-related gene2 (PvSR2) produces a short (S) PvSR2 transcript (S-PvSR2) driven by an intronic promoter. Here, we demonstrate that S-PvSR2 encodes a bean MRE-binding transcription factor1 (PvMTF-1) that confers Cd tolerance in tobacco (Nicotiana tabacum). PvMTF-1 expression was up-regulated by Cd at the levels of RNA and protein. Importantly, expression of PvMTF-1 in tobacco enhanced Cd tolerance, indicating its role in regulating Cd resistance in planta. This was achieved through direct regulation of a feedback-insensitive Anthranilate Synthase α-2 chain gene (ASA2), which catalyzes the first step for tryptophan biosynthesis. In vitro and in vivo DNA-protein interaction studies further revealed that PvMTF-1 directly binds to the MRE in the ASA2 promoter, and this binding depends on the zinc finger-like motif of PvMTF-1. Through modulating ASA2 up-regulation by Cd, PvMTF-1 increased free tryptophan level and subsequently reduced Cd accumulation, thereby enhancing Cd tolerance of transgenic tobacco plants. Consistent with this observation, tobacco transiently overexpressing ASA2 also exhibited increased tolerance to Cd. We conclude that PvMTF-1 is a zinc finger-like transcription factor that links MRE to Cd resistance in transgenic tobacco through activation of tryptophan biosynthesis. PMID:25624396

An Economic Analysis of Residential Photovoltaic Systems with and without Energy Storage

NASA Astrophysics Data System (ADS)

Kizito, Rodney

Residential photovoltaic (PV) systems serve as a source of electricity generation that is separate from the traditional utilities. Investor investment into residential PV systems provides several financial benefits such as federal tax credit incentives for installation, net metering credit from excess generated electricity added back to the grid, and savings in price per kilowatt-hour (kWh) from the PV system generation versus the increasing conventional utility price per kWh. As much benefit as stand-alone PV systems present, the incorporation of energy storage yields even greater benefits. Energy storage (ES) is capable of storing unused PV provided energy from daytime periods of high solar supply but low consumption. This allows the investor to use the stored energy when the cost of conventional utility power is high, while also allowing for excess stored energy to be sold back to the grid. This paper aims to investigate the overall returns for investor's investing in solely PV and ES-based PV systems by using a return of investment (ROI) economic analysis. The analysis is carried out over three scenarios: (1) residence without a PV system or ES, (2) residence with just a PV system, and (3) residence with both a PV system and ES. Due to the variation in solar exposure across the regions of the United States, this paper performs an analysis for eight of the top solar market states separately, accounting for the specific solar generation capabilities of each state. A Microsoft Excel tool is provided for computation of the ROI in scenario 2 and 3. A benefit-cost ration (BCR) is used to depict the annual economic performance of the PV system (scenario 2) and PV + ES system (scenario 3). The tool allows the user to adjust the variables and parameters to satisfy the users' specific investment situation.

Significance of measured intraoperative portal vein flows after thrombendvenectomy in deceased donor liver transplantations with portal vein thrombosis.

PubMed

Draoua, Mark; Titze, Nicole; Gupta, Amar; Fernandez, Hoylan T; Ramsay, Michael; Saracino, Giovanna; McKenna, Gregory; Testa, Giuliano; Klintmalm, Goran B; Kim, Peter T W

2017-08-01

Adequate portal vein (PV) flow in liver transplantation is essential for a good outcome, and it may be compromised in patients with portal vein thrombosis (PVT). This study evaluated the impact of intraoperatively measured PV flow after PV thrombendvenectomy on outcomes after deceased donor liver transplantation (DDLT). The study included 77 patients over a 16-year period who underwent PV thrombendvenectomy with complete flow data. Patients were classified into 2 groups: high PV flow (>1300 mL/minute; n = 55) and low PV flow (≤1300 mL/minute; n = 22). Postoperative complications and graft survival were analyzed according to the PV flow. The 2 groups were similar in demographic characteristics. Low PV flow was associated with higher cumulative rates of biliary strictures (P = 0.02) and lower 1-, 2-, and 5-year graft survival (89%, 85%, and 68% versus 64%, 55%, and 38%, respectively; P = 0.002). There was no difference in the incidence of postoperative PVT between the groups (1.8% versus 9.1%; P = 0.19). No biliary leaks or hepatic artery thromboses were reported in either group. By multivariate analyses, age >60 years (hazard ratio [HR], 3.04, 95% confidence interval [CI], 1.36-6.82; P = 0.007) and low portal flow (HR, 2.31; 95% CI, 1.15-4.65; P = 0.02) were associated with worse survival. In conclusion, PV flow <1300 mL/minute after PV thrombendvenectomy for PVT during DDLT was associated with higher rates of biliary strictures and worse graft survival. Consideration should be given to identifying reasons for low flow and performing maneuvers to increase PV flow when intraoperative PV flows are <1300 mL/minute. Liver Transplantation 23 1032-1039 2017 AASLD. © 2017 by the American Association for the Study of Liver Diseases.

Enhancement of photovoltaic cell performance using periodic triangular gratings

NASA Astrophysics Data System (ADS)

Bordatchev, Evgueni; Tauhiduzzaman, Mohammed; Dey, Rajat

2014-01-01

The solar energy industry strives to produce more efficient and yet cost effective solar panels each consisting of an array of photovoltaic (PV) cells. The goal of this study was to enhance the performance of PV cells through increasing the cells' optical efficiency defined as a percentage of surface incident light that reaches the PV material. This was achieved through the reduction of waveguide decoupling loss and Fresnel reflection losses by integrating specific nonimaging micro-optical structures on the top surface of existing PV cells. Due to this integration, optical efficiency and performance were increased through the enhancement of light trapping, light guiding, and in-coupling functionalities. Periodic triangular gratings (PTGs) were designed, nonsequentially modeled, optimized, and fabricated in polydimethylsiloxane as proposed micro-optical structures. Then the performance of PV cells with and without integrated PTGs was evaluated and compared. Initial optical simulation results show that an original PV cell (without PTG) exhibits an average optical efficiency of 32.7% over a range of incident light angles between 15 and 90 deg. Integration of the PTG allows the capture of incoming sunlight by total internal reflection (TIR), whence it is reflected back onto the PV cell for multiple consecutive chances for absorption and PV conversion. Geometry of the PTG was optimized with respect to an angle of light incidence of {15, 30, 45, 60, 75, 90} deg. Optical efficiency of the geometrically optimized PTGs was then analyzed under the same set of incident light angles and a maximum optical efficiency of 54.1% was observed for a PV cell with integrated PTG optimized at 90 deg. This is a 53.3% relative improvement in optical performance when compared to an original PV cell. Functional PTG prototypes were then fabricated with optical surface quality (below 10 nm Ra) and integrated with PV cells demonstrating an increase in maximum power by 1.08 mW/cm (7.6% improvement in PV performance) and in short circuit current by 2.39 mA/cm (6.4% improvement).

Mixed addenda polyoxometalate "solutions" for stationary energy storage.

PubMed

Pratt, Harry D; Anderson, Travis M

2013-11-28

A series of redox flow batteries utilizing mixed addenda (vanadium and tungsten), phosphorus-based polyoxometalates (A-α-PV3W9O40(6-), B-α-PV3W9O40(6-), and P2V3W15O62(9-)) were prepared and tested. Cyclic voltammetry and bulk electrolysis experiments on the Keggin compounds (A-α-PV3W9O40(6-) and B-α-PV3W9O40(6-)) established that the vanadium centers of these compounds could be used as the positive electrode (PV(IV)3W(VI)9O40(9-)/PV(V)3W(VI)9O40(6-)), and the tungsten centers could be used as the negative electrode (PV(IV)3W(VI)9O40(9-)/PV(IV)3W(V)3W(VI)6O40(12-)) since these electrochemical processes are separated by about 1 V. The results showed that A-α-PV3W9O40(6-) (where A indicates adjacent, corner-sharing vanadium atoms) had coulombic efficiencies (charge in divided by charge out) above 80%, while the coulombic efficiency of B-α-PV3W9O40(6-) (where B indicates adjacent edge-sharing vanadium atoms) fluctuated between 50% and 70% during cycling. The electrochemical yield, a measurement of the actual charge or discharge observed in comparison with the theoretical charge, was between 40% and 50% for A-α-PV3W9O40(6-), and (31)P NMR showed small amounts of PV2W10O40(5-) and PVW11O40(4-) formed with cycling. The electrochemical yield for B-α-PV3W9O40(6-) decreased from 90% to around 60% due to precipitation of the compound on the electrode, but there were no decomposition products detected in the solution by (31)P NMR, and infrared data on the electrode suggested that the cluster remained intact. Testing of P2V3W15O62(9-) (Wells-Dawson structure) suggested higher charge density clusters were not as suitable as the Keggin structures for a redox flow battery due to the poor stability and inaccessibility of the highly reduced materials.

Design of a Glenn Research Center Solar Field Grid-Tied Photovoltaic Power System

NASA Technical Reports Server (NTRS)

Eichenberg, Dennis J.

2009-01-01

The NASA Glenn Research Center (GRC) designed, developed, and installed, a 37.5 kW DC photovoltaic (PV) Solar Field in the GRC West Area in the 1970s for the purpose of testing PV panels for various space and terrestrial applications. The PV panels are arranged to provide a nominal 120 VDC. The GRC Solar Field has been extremely successful in meeting its mission. The PV panels and the supporting electrical systems are all near their end of life. GRC has designed a 72 kW DC grid-tied PV power system to replace the existing GRC West Area Solar Field. The 72 kW DC grid-tied PV power system will provide DC solar power for GRC PV testing applications, and provide AC facility power for all times that research power is not required. A grid-tied system is connected directly to the utility distribution grid. Facility power can be obtained from the utility system as normal. The PV system is synchronized with the utility system to provide power for the facility, and excess power is provided to the utility for use by all. The project transfers space technology to terrestrial use via nontraditional partners. GRC personnel glean valuable experience with PV power systems that are directly applicable to various space power systems, and provide valuable space program test data. PV power systems help to reduce harmful emissions and reduce the Nation s dependence on fossil fuels. Power generated by the PV system reduces the GRC utility demand, and the surplus power aids the community. Present global energy concerns reinforce the need for the development of alternative energy systems. Modern PV panels are readily available, reliable, efficient, and economical with a life expectancy of at least 25 years. Modern electronics has been the enabling technology behind grid-tied power systems, making them safe, reliable, efficient, and economical with a life expectancy of at least 25 years. The report concludes that the GRC West Area grid-tied PV power system design is viable for a reliable, maintenance free, long life power system that is of significant value to NASA and the community.

Trophic transfer and effects of DDT in male hornyhead turbot (Pleuronichthys verticalis) from Palos Verdes Superfund site, CA (USA) and comparisons to field monitoring.

PubMed

Crago, Jordan; Xu, Elvis Genbo; Kupsco, Allison; Jia, Fang; Mehinto, Alvine C; Lao, Wenjian; Maruya, Keith A; Gan, Jay; Schlenk, Daniel

2016-06-01

High concentrations of DDT and metabolites (ΣDDT) have been detected in sediment and the demersal flatfish hornyhead turbot (Pleuronichtys verticalis) collected from Palos Verdes (PV), California, USA, a site contaminated with over 100 metric tons of DDT throughout 1960s-70s. This study was conducted to assess the transfer of ΣDDT from PV-sediment into polychaetes (Neanthes arenaceodentata) and hornyhead turbot, and to investigate if the responses in turbots from two different laboratory exposures mimic those in turbots caught in PV (PV-turbot). Turbot fed PV-sediment-contaminated polychaete for 7 days had liver concentrations of ΣDDT similar to PV-turbot. After 28 days, ΣDDT also accumulated in livers of turbot gavaged with a ΣDDT mixture. In vitro cell bioassays indicated significant increases of 17β-estradiol equivalents (EEQ) in turbot bile extracts as compared to the control in the 7-day study. These responses corresponded to those measured in PV-fish. Glucocorticoid receptor (GR), anti-androgen receptor (anti-AR), estrogen receptor (ER) or aryl hydrocarbon receptor (AhR) activities were also observed in extracts of PV-sediment, and PV-sediment-exposed worm. Anti-AR, AhR and GR activities were significantly higher in PV-sediment than reference sediment (San Diego, SD). Higher transcripts of hepatic VTG, ERα and ERβ were found in PV-turbot than SD-turbot, but were unaltered in fish exposed to sediment-contaminated worms for the 7-day study. In contrast, liver extracts from the 28-day treatment of ΣDDT showed lower EEQ but similar hepatic VTG and ERβ transcripts relative to those of PV-turbot. These data indicated that trophic transfer of sediment-associated DDT in 7-day exposures corresponded to field measurements of DDT residues and in vitro ER bioactivities, but failed to mimic in vivo biological effects observed in field fish. In contrast, treatment with ΣDDT alone for 28 days mimicked in vivo biological effects of DDTs in PV fish, but did not correspond to liver concentrations or in vitro bioactivities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Role of glutamic acid decarboxylase 67 in regulating cortical parvalbumin and GABA membrane transporter 1 expression: implications for schizophrenia.

PubMed

Curley, Allison A; Eggan, Stephen M; Lazarus, Matt S; Huang, Z Josh; Volk, David W; Lewis, David A

2013-02-01

Markers of GABA neurotransmission are altered in multiple regions of the neocortex in individuals with schizophrenia. Lower levels of glutamic acid decarboxylase 67 (GAD67) mRNA and protein, which is responsible for most cortical GABA synthesis, are accompanied by lower levels of GABA membrane transporter 1 (GAT1) mRNA. These alterations are thought to be most prominent in the parvalbumin (PV)-containing subclass of interneurons, which also contain lower levels of PV mRNA. Since GAT1 and PV each reduce the availability of GABA at postsynaptic receptors, lower levels of GAT1 and PV mRNAs have been hypothesized to represent compensatory responses to an upstream reduction in cortical GABA synthesis in schizophrenia. However, such cause-and-effect hypotheses cannot be directly tested in a human illness. Consequently, we used two mouse models with reduced GAD67 expression specifically in PV neurons (PV(GAD67+/-)) or in all interneurons (GABA(GAD67+/-)) and quantified GAD67, GAT1 and PV mRNA levels using methods identical to those employed in studies of schizophrenia. Cortical levels of PV or GAT1 mRNAs were not altered in PV(GAD67+/-) mice during postnatal development or in adulthood. Furthermore, cellular analyses confirmed the predicted reduction in GAD67 mRNA, but failed to show a deficit in PV mRNA in these animals. Levels of PV and GAT1 mRNAs were also unaltered in GABA(GAD67+/-) mice. Thus, mouse lines with cortical reductions in GAD67 mRNA that match or exceed those present in schizophrenia, and that differ in the developmental timing and cell type-specificity of the GAD67 deficit, failed to provide proof-of-concept evidence that lower PV and GAT1 expression in schizophrenia are a consequence of lower GAD67 expression. Together, these findings suggest that the correlated decrements in cortical GAD67, PV and GAT1 mRNAs in schizophrenia may be a common consequence of some other upstream factor. Copyright © 2012 Elsevier Inc. All rights reserved.

Progressing Deployment of Solar Photovoltaic Installations in the United States

NASA Astrophysics Data System (ADS)

Kwan, Calvin Lee

2011-07-01

This dissertation evaluates the likelihood of solar PV playing a larger role in national and state level renewable energy portfolios. I examine the feasibility of large-scale solar PV arrays on college campuses, the financials associated with large-scale solar PV arrays and finally, the influence of environmental, economic, social and political variables on the distribution of residential solar PV arrays in the United States. Chapter two investigates the challenges and feasibility of college campuses adopting a net-zero energy policy. Using energy consumption data, local solar insolation data and projected campus growth, I present a method to identify the minimum sized solar PV array that is required for the City College campus of the Los Angeles Community College District to achieve net-zero energy status. I document how current energy demand can be reduced using strategic demand side management, with remaining energy demand being met using a solar PV array. Chapter three focuses on the financial feasibility of large-scale solar PV arrays, using the proposed City College campus array as an example. I document that even after demand side energy management initiatives and financial incentives, large-scale solar PV arrays continue to have ROIs greater than 25 years. I find that traditional financial evaluation methods are not suitable for environmental projects such as solar PV installations as externalities are not taken into account and therefore calls for development of alternative financial valuation methods. Chapter four investigates the influence of environmental, social, economic and political variables on the distribution of residential solar PV arrays across the United States using ZIP code level data from the 2000 US Census. Using data from the National Renewable Energy Laboratory's Open PV project, I document where residential solar PVs are currently located. A zero-inflated negative binomial model was run to evaluate the influence of selected variables. Using the same model, predicted residential solar PV shares were generated and illustrated using GIS software. The results of this model indicate that solar insolation, state energy deregulation and cost of electricity are statistically significant factors positively correlated with the adoption of residential solar PV arrays. With this information, policymakers at the towns and cities level can establish effective solar PV promoting policies and regulations for their respective locations.

Fluid mechanics of Windkessel effect.

PubMed

Mei, C C; Zhang, J; Jing, H X

2018-01-08

We describe a mechanistic model of Windkessel phenomenon based on the linear dynamics of fluid-structure interactions. The phenomenon has its origin in an old-fashioned fire-fighting equipment where an air chamber serves to transform the intermittent influx from a pump to a more steady stream out of the hose. A similar mechanism exists in the cardiovascular system where blood injected intermittantly from the heart becomes rather smooth after passing through an elastic aorta. In existing haeodynamics literature, this mechanism is explained on the basis of electric circuit analogy with empirical impedances. We present a mechanistic theory based on the principles of fluid/structure interactions. Using a simple one-dimensional model, wave motion in the elastic aorta is coupled to the viscous flow in the rigid peripheral artery. Explicit formulas are derived that exhibit the role of material properties such as the blood density, viscosity, wall elasticity, and radii and lengths of the vessels. The current two-element model in haemodynamics is shown to be the limit of short aorta and low injection frequency and the impedance coefficients are derived theoretically. Numerical results for different aorta lengths and radii are discussed to demonstrate their effects on the time variations of blood pressure, wall shear stress, and discharge. Graphical Abstract A mechanistic analysis of Windkessel Effect is described which confirms theoretically the well-known feature that intermittent influx becomes continuous outflow. The theory depends only on the density and viscosity of the blood, the elasticity and dimensions of the vessel. Empirical impedence parameters are avoided.

Wind effect on PV module temperature: Analysis of different techniques for an accurate estimation.

NASA Astrophysics Data System (ADS)

Schwingshackl, Clemens; Petitta, Marcello; Ernst Wagner, Jochen; Belluardo, Giorgio; Moser, David; Castelli, Mariapina; Zebisch, Marc; Tetzlaff, Anke

2013-04-01

In this abstract a study on the influence of wind to model the PV module temperature is presented. This study is carried out in the framework of the PV-Alps INTERREG project in which the potential of different photovoltaic technologies is analysed for alpine regions. The PV module temperature depends on different parameters, such as ambient temperature, irradiance, wind speed and PV technology [1]. In most models, a very simple approach is used, where the PV module temperature is calculated from NOCT (nominal operating cell temperature), ambient temperature and irradiance alone [2]. In this study the influence of wind speed on the PV module temperature was investigated. First, different approaches suggested by various authors were tested [1], [2], [3], [4], [5]. For our analysis, temperature, irradiance and wind data from a PV test facility at the airport Bolzano (South Tyrol, Italy) from the EURAC Institute of Renewable Energies were used. The PV module temperature was calculated with different models and compared to the measured PV module temperature at the single panels. The best results were achieved with the approach suggested by Skoplaki et al. [1]. Preliminary results indicate that for all PV technologies which were tested (monocrystalline, amorphous, microcrystalline and polycrystalline silicon and cadmium telluride), modelled and measured PV module temperatures show a higher agreement (RMSE about 3-4 K) compared to standard approaches in which wind is not considered. For further investigation the in-situ measured wind velocities were replaced with wind data from numerical weather forecast models (ECMWF, reanalysis fields). Our results show that the PV module temperature calculated with wind data from ECMWF is still in very good agreement with the measured one (R² > 0.9 for all technologies). Compared to the previous analysis, we find comparable mean values and an increasing standard deviation. These results open a promising approach for PV module temperature estimation using meteorological parameters. References: [1] Skoplaki, E. et al., 2008: A simple correlation for the operating temperature of photovoltaic modules of arbitrary mounting, Solar Energy Materials & Solar Cells 92, 1393-1402 [2] Skoplaki, E. et al., 2008: Operating temperature of photovoltaic modules: A survey of pertinent correlations, Renewable Energy 34, 23-29 [3] Koehl, M. et al., 2011: Modeling of the nominal operating cell temperature based on outdoor weathering, Solar Energy Materials & Solar Cells 95, 1638-1646 [4] Mattei, M. et al., 2005: Calculation of the polycrystalline PV module temperature using a simple method of energy balance, Renewable Energy 31, 553-567 [5] Kurtz, S. et al.: Evaluation of high-temperature exposure of rack-mounted photovoltaic modules

Quasi-static time-series simulation using OpenDSS in IEEE distribution feeder model with high PV penetration and its impact on solar forecasting

NASA Astrophysics Data System (ADS)

Mohammed, Touseef Ahmed Faisal

Since 2000, renewable electricity installations in the United States (excluding hydropower) have more than tripled. Renewable electricity has grown at a compounded annual average of nearly 14% per year from 2000-2010. Wind, Concentrated Solar Power (CSP) and solar Photo Voltaic (PV) are the fastest growing renewable energy sectors. In 2010 in the U.S., solar PV grew over 71% and CSP grew by 18% from the previous year. Globally renewable electricity installations have more than quadrupled from 2000-2010. Solar PV generation grew by a factor of more than 28 between 2000 and 2010. The amount of CSP and solar PV installations are increasing on the distribution grid. These PV installations transmit electrical current from the load centers to the generating stations. But the transmission and distribution grid have been designed for uni-directional flow of electrical energy from generating stations to load centers. This causes imbalances in voltage and switchgear of the electrical circuitry. With the continuous rise in PV installations, analysis of voltage profile and penetration levels remain an active area of research. Standard distributed photovoltaic (PV) generators represented in simulation studies do not reflect the exact location and variability properties such as distance between interconnection points to substations, voltage regulators, solar irradiance and other environmental factors. Quasi-Static simulations assist in peak load planning hour and day ahead as it gives a time sequence analysis to help in generation allocation. Simulation models can be daily, hourly or yearly depending on duty cycle and dynamics of the system. High penetration of PV into the power grid changes the voltage profile and power flow dynamically in the distribution circuits due to the inherent variability of PV. There are a number of modeling and simulations tools available for the study of such high penetration PV scenarios. This thesis will specifically utilize OpenDSS, a open source Distribution System Simulator developed by Electric Power Research Institute, to simulate grid voltage profile with a large scale PV system under quasi-static time series considering variations of PV output in seconds, minutes, and the average daily load variations. A 13 bus IEEE distribution feeder model is utilized with distributed residential and commercial scale PV at different buses for simulation studies. Time series simulations are discussed for various modes of operation considering dynamic PV penetration at different time periods in a day. In addition, this thesis demonstrates simulations taking into account the presence of moving cloud for solar forecasting studies.

Understanding the Evolution of Customer Motivations and Adoption Barriers in Residential Solar Markets: Survey Data

DOE Data Explorer

Sigrin, Ben; Dietz, Tom; Henry, Adam; Ingle, Aaron; Lutzenhiser, Loren; Moezzi, Mithra; Spielman, Seth; Stern, Paul; Todd, Annika; Tong, James; Wolske, Kim

2017-06-12

This research focused on accelerating solar photovoltaic (PV) diffusion by collecting new market data and developing predictive modeling frameworks to test and refine understandings of household level motivations for adopting solar. Three different household-level surveys were fielded: one for households who had installed PV on their current home or had signed a contract to do so (the Adopter survey), one for households that had seriously considered PV but had not installed it (the Considerer survey), and one for the general population who did not have PV on their current home (the general population survey or GPS). Survey respondents were from four U.S. states: New Jersey, New York, Arizona, and California. Details of recruiting and sampling are documented below. Research projects on residential PV adoption often collect data only from PV adopters or from the general population. One of the innovations of this project was the three-pronged household survey data collection. By collecting similar data from three fairly different "statuses" with respect to adoption, the surveys provide a basis for understanding how those who do not have rooftop PV differ from those who have, for how and why people do (or don't) transition from not having to having rooftop PV on their home, and for understanding the characteristics and viewpoints of households who have scarcely, or not at all, entered the "PV consideration" track. All three surveys covered single-family owner-occupied households in each of the four target states used in the project -- Arizona, California, New Jersey, and New York - allowing a comparative approach to understanding how the factors that affect PV adoption vary by geography and policy conditions. The General Population and Considerer surveys provide a basis for understanding opinions about and interest in solar, and how these relate to household demographics and other conditions. Paired with the Adopter survey, they also provide data for understanding how those who do not have rooftop PV differ from those who have, and for how and why people do (or don't) transition from not having to having rooftop PV on their home. The Adopter survey questions were designed to capture a broad range of information on what motivates and impedes households to install rooftop PV, as well as the details and timing of the decision and installation. Survey instrument development drew from existing PV adoption survey instruments, PV adoption literature, and research team experience, as well as from past work on household interest in energy efficiency, environmental attitudes, purchasing tendencies, and related knowledge. Early interviews and discussions with installers and others in the PV industry were also taken into consideration.

LCP- LIFETIME COST AND PERFORMANCE MODEL FOR DISTRIBUTED PHOTOVOLTAIC SYSTEMS

NASA Technical Reports Server (NTRS)

Borden, C. S.

1994-01-01

The Lifetime Cost and Performance (LCP) Model was developed to assist in the assessment of Photovoltaic (PV) system design options. LCP is a simulation of the performance, cost, and revenue streams associated with distributed PV power systems. LCP provides the user with substantial flexibility in specifying the technical and economic environment of the PV application. User-specified input parameters are available to describe PV system characteristics, site climatic conditions, utility purchase and sellback rate structures, discount and escalation rates, construction timing, and lifetime of the system. Such details as PV array orientation and tilt angle, PV module and balance-of-system performance attributes, and the mode of utility interconnection are user-specified. LCP assumes that the distributed PV system is utility grid interactive without dedicated electrical storage. In combination with a suitable economic model, LCP can provide an estimate of the expected net present worth of a PV system to the owner, as compared to electricity purchased from a utility grid. Similarly, LCP might be used to perform sensitivity analyses to identify those PV system parameters having significant impact on net worth. The user describes the PV system configuration to LCP via the basic electrical components. The module is the smallest entity in the PV system which is modeled. A PV module is defined in the simulation by its short circuit current, which varies over the system lifetime due to degradation and failure. Modules are wired in series to form a branch circuit. Bypass diodes are allowed between modules in the branch circuits. Branch circuits are then connected in parallel to form a bus. A collection of buses is connected in parallel to form an increment to capacity of the system. By choosing the appropriate series-parallel wiring design, the user can specify the current, voltage, and reliability characteristics of the system. LCP simulation of system performance is site-specific and follows a three-step procedure. First the hourly power produced by the PV system is computed using a selected year's insolation and temperature profile. For this step it is assumed that there are no module failures or degradation. Next, the monthly simulation is performed involving a month to month progression through the lifetime of the system. In this step, the effects of degradation, failure, dirt accumulation and operations/maintenance efforts on PV system performance over time are used to compute the monthly power capability fraction. The resulting monthly power capability fractions are applied to the hourly power matrix from the first step, giving the anticipated hourly energy output over the lifetime of the system. PV system energy output is compared with the PV system owner's electricity demand for each hour. The amount of energy to be purchased from or sold to the utility grid is then determined. Monthly expenditures on the PV system and the purchase of electricity from the utility grid are also calculated. LCP generates output reports pertaining to the performance of the PV system, and system costs and revenues. The LCP model, written in SIMSCRIPT 2.5 for batch execution on an IBM 370 series computer, was developed in 1981.

Nonstationarity Versus Intermittency: A Wavelet/Multifractal Perspective with Operational Criteria

NASA Astrophysics Data System (ADS)

Davis, A. B.; Marshak, A.

2001-12-01

The signal from a seismograph is mostly low-level white background- and/or instrumental noise with the occasional burst of high-level transient activity that results from a (generally) remote earthquake. The former component can justifiably be deemed stationary on intuitive grounds; by contrast, the latter component has been called ``nonstationary'' by statisticians since it seriously perturbs their running means and variances over relatively short time-scales. Recall here that the eminently theoretical definition of stationarity as time-invariance of ensemble-averages is of little use when a single realization is available, the generic case in geophysics. A high-pass filtered trace of turbulent velocity looks much the same as the seismic signal but the bursts are seen by physicists as a manifestation of ``intermittency'' rather than nonstationarity. We side with the second characterization by allegiance, but fully appreciate the statistician's concern for robustness. In this context, the weaknesses of the nonstationarity model are: the over-reliance on low-order moments (Gaussian ideology), the restriction on scales, and the need for a threshold to define ``serious perturbation.'' At the same time, an added advantage of the intermittency model for bursts is that it frees up the notion of nonstationarity to describe the low-pass components of turbulent geophysical signals which are as important as their high-pass counterparts, if not more, in many applications. The stationarity versus nonstationarity question is best recast in terms of spatial correlations and scaling enables us to do this, even when dealing with a single realization: are they short-range (as in ``noises'') or long-range (as in ``motions'')? However, care must be taken about what spatial statistic to use here, and finite sample-size effects can add to the confusion. Every quantification of intermittency based on higher-order multifractal statistics should also be scrutinized for finite-sample effects. Using the unifying framework of wavelet transforms for multifractal analysis, we offer unambiguous criteria to decide whether a given dataset that is scaling (within limits) is stationary or not, and then intermittent or not. In the latter case, there is an arbitrary threshold that is easily set in any specific application. Having established the presence of significant intermittency, we can anticipate that the selection of one particular brand of multifractality versus another will be quite difficult based on data alone. This relates in particular to the proliferation of competing multifractal theories of turbulence in spite of on-going efforts to collect high-quality data.

NREL Finds Nanotube Semiconductors Well-suited for PV Systems | News | NREL

Science.gov Websites

photoinduced electron transfer for emerging organic semiconductors such as single-walled carbon nanotubes (SWCNT) that can be used in organic PV devices. In organic PV devices, after a photon is absorbed Larson, and Steven Strauss from Colorado State University. Organic PV devices involve an interface

An overview of photovoltaic applications in space

NASA Technical Reports Server (NTRS)

Wasel, Robert A.

1987-01-01

An overview is given of the uses of photovoltaic (PV) power in space. The contribution of PV systems on unmanned, low Earth orbit and inner planetary missions is noted. The development of PV technology along the two paths of high efficiency and high power is discussed. The importance of increasing the service life of PV systems is covered.

Solar Market Research and Analysis Projects | Solar Research | NREL

Science.gov Websites

increase the effectiveness and reduce the variability and cost of PV operations and maintenance (O&M significantly drive up the cost of electricity for PV systems. To help reduce PV O&M costs and improve PV -Storage: Reducing Barriers Through Cost-Optimization and Market Characterization While falling costs have

Materials and Devices | Photovoltaic Research | NREL

Science.gov Websites

Polycrystalline Thin-Film PV Cadmium telluride (CdTe) solar cells Copper indium gallium diselenide (CIGS) solar cells Perovskite and Organic PV Perovskite solar cells Perovskite Patent Portfolio Organic PV (OPV ) solar cells Advanced Materials, Devices, and Concepts We explore new PV materials using high-throughput

77 FR 73018 - Crystalline Silicon Photovoltaic Cells, Whether or Not Assembled Into Modules, From the People's...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-07

...., Ltd. (Chengdu) PV Module Co., Ltd. Canadian Solar International Canadian Solar 24.48 Limited..... Chint Solar (Zhejiang) 24.48 Co., Ltd. Suzhou Shenglong PV-Tech Co., Ltd Suzhou Shenglong PV-TECH 24.48.... Jetion Solar (China) Co., Ltd.... Jetion Solar (China) 24.48 Co., Ltd. Jiangsu Green Power PV Co., Ltd...

Graduate Students Gain Hands-On PV Experience from NREL Researchers | News

Science.gov Websites

PV Experience (HOPE) Workshop, learning from top solar scientists at the U.S. Department of Energy's | NREL Graduate Students Gain Hands-On PV Experience from NREL Researchers Graduate Students Gain Hands-On PV Experience from NREL Researchers August 10, 2017 Two students, one standing, one

Grid Simulation and Power Hardware-in-the-Loop | Grid Modernization | NREL

Science.gov Websites

used PHIL to investigate the effects of advanced solar PV inverters on Hawaii's grid. A variety of PV Evaluating the Performance of Methods for Coordinated Control of Distributed Residential PV/Energy Storage photovoltaics (PV)-battery energy storage inverter control applied across an electric distribution system

New Solar PV Tool Accurately Calculates Degradation Rates, Saving Money and

Science.gov Websites

Guiding Business Decisions | News | NREL New Solar PV Tool Accurately Calculates Degradation Rates, Saving Money and Guiding Business Decisions News Release: New Solar PV Tool Accurately Calculates ; said Dirk Jordan, engineer and solar PV researcher at NREL. "We spent years building consensus in

Researchers at NREL Find Fewer Failures of PV Panels and Different

Science.gov Websites

10, 2017 Overall failure rates for photovoltaic (PV) solar panels have fallen dramatically when Failures of PV Panels and Different Degradation Modes in Systems Installed after 2000 Researchers at NREL Find Fewer Failures of PV Panels and Different Degradation Modes in Systems Installed after 2000 April

Reliability and Engineering | Photovoltaic Research | NREL

Science.gov Websites

-Time PV and Solar Resource Testing We study long-term performance, reliability, and failures of PV (NCPV) at NREL, we focus on photovoltaic (PV) reliability research and development (R&D) to improve PV technologies. We test modules and systems for long-term performance and stress them in the field

Research | Photovoltaic Research | NREL

Science.gov Websites

-V cells Hybrid tandems Polycrystalline Thin-Film PV CdTe solar cells CIGS solar cells Perovskites and Organic PV Perovskite solar cells Organic PV solar cells Advanced Materials, Devices, and Science Interfacial and Surface Science Reliability and Engineering Real-Time PV and Solar Resource

Molecular detection of Xanthomonas oryzae pv. oryzae, Xanthomonas oryzae pv. oryzicola, and Burkholderia glumae in infected rice seeds and leaves

USDA-ARS?s Scientific Manuscript database

Polymerase chain reaction (PCR) is particularly useful for plant pathogen detection. In the present study, multiplex PCR and SYBR green real-time PCR were developed to facilitate simultaneous detection of three important rice pathogens, Xanthomonas oryzae pv. oryzae, X. oryzae pv. oryzicola, and Bur...

Evaluating the Technical and Economic Performance of PV Plus Storage Power Plants: Report Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul L.; Margolis, Robert M.; Eichman, Joshua D.

The decreasing costs of both PV and energy storage technologies have raised interest in the creation of combined PV plus storage systems to provide dispatchable energy and reliable capacity. In this study, we examine the tradeoffs among various PV plus storage configurations and quantify the impact of configuration on system net value.

Evaluating the Technical and Economic Performance of PV Plus Storage Power Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denholm, Paul L.; Margolis, Robert M.; Eichman, Joshua D.

The decreasing costs of both PV and energy storage technologies have raised interest in the creation of combined PV plus storage systems to provide dispatchable energy and reliable capacity. In this study, we examine the tradeoffs among various PV plus storage configurations and quantify the impact of configuration on system net value.

The Evolving Market Structure of the U.S. Residential Solar PV Installation Industry, 2000-2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

OShaughnessy, Eric J.

This study uses data on over 900,000 solar PV installations to summarize the evolving market structure of the U.S. residential solar PV installation industry. Over 8,000 companies have installed residential PV systems in the United States. The vast majority of these installers are small local companies. At the same time, a subset of national-scale high-volume PV installation companies hold high market shares. This study examines the factors behind these trends in market concentration, including the role of customer financing options.

Photovoltaics Innovation Roadmap Request for Information Summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

None, None

On June 28, 2017, the U.S. Department of Energy’s Solar Energy Technologies Office (SETO) released the Photovoltaics (PV) Innovation Roadmap Request for Information (RFI) for public response and comment. The RFI sought feedback from PV stakeholders, including research and commercial communities, about the most important research and development (R&D) pathways to improve PV cell and module technology to reach the SETO’s SunShot 2030 cost targets of $0.03/W for utility PV installations, $0.04/W for commercial scale installations, and $0.05/W for residential PV installations.

Intelligent control of PV system on the basis of the fuzzy recurrent neuronet*

NASA Astrophysics Data System (ADS)

Engel, E. A.; Kovalev, I. V.; Engel, N. E.

2016-04-01

This paper presents the fuzzy recurrent neuronet for PV system’s control. Based on the PV system’s state, the fuzzy recurrent neural net tracks the maximum power point under random perturbations. The validity and advantages of the proposed intelligent control of PV system are demonstrated by numerical simulations. The simulation results show that the proposed intelligent control of PV system achieves real-time control speed and competitive performance, as compared to a classical control scheme on the basis of the perturbation & observation algorithm.

Photovoltaic power generation; Proceedings of the EC Contractors' Meeting, Hamburg, West Germany, July 12, 13, 1983

NASA Astrophysics Data System (ADS)

Palz, W.

Several operational examples of photovoltaic (PV) power generation systems in Europe are described. The systems include: a 300 kW power plant in Pellworm, West Germany; the Tremiti desalination plant in Tremiti, Italy; and the Kythnos PV power plant in Kythnos, Greece. Consideration is also given to a PV-powered swimming pool heating system in Chevretogne, Belgium; a rural electrification program using PV power plants in French Guyana; a solar-wind project on Terschelling Island, the Netherlands; and a PV power plant for hydrogen production and water pumping in Hoboken, Belgium. A 30-kW power station in Marchwood, England and the Nice airport survey and control system are also cited as examples of successful PV power generation systems.

New Best-Practices Guide for Photovoltaic System Operations and Maintenance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fact sheet summarizing technical report TP-7A40-67553. As solar photovoltaic (PV) systems have continued their transition from niche applications into large, mature markets in the United States, their potential as financial investments has risen accordingly. Mainstream investors, however, need to feel confident about the risk and return of solar photovoltaic (PV) systems before committing funds. A major influence on risk and return for PV is operations and maintenance (O&M) - but O&M practices and costs vary widely across the United States, making these variables difficult for investors to predict. To address this barrier to continued PV investment, the PV O&M Workingmore » Group has developed a new best-practices guide for PV O&M.« less

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Astrophysics Data System (ADS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

Status of DOE and AID stand-alone photovoltaic system field tests

NASA Technical Reports Server (NTRS)

Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

1984-01-01

The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.